A Practical Approach to Anesthesia for Emergency Surgery Manju N Gandhi, Anila D Malde, Amala G Kudalkar, Hemangi S Karnik
INDEX
A
Abdominal
closure 522
compartment syndrome 173, 174, 523
emergencies 345
trauma 512
wall defects 346
Abortion and intrauterine fetal demise 253
Abruptio placentae 256
Acid suppression 212
Acidosis 522
Activation of hospital disaster management plan 609
Acute
aortic
incompetence 128
regurgitation 45
fatty liver of pregnancy 289
hydrocephalus 427
infective endocarditis 269
ischemic
mitral regurgitation 125
stroke 444
lower extremity ischemia 154
mitral regurgitation 124, 125
primary nonischemic mitral regurgitation 124
renal failure 29, 294
secondary mitral regurgitation in cardiomyopathy 125
variceal hemorrhage 213
Airway
assessment and management 490
evaluation and management 571
in MFT 571
management in MFT 571
Alfentanil 73
Alkaline diuresis 540
Analgesia 426, 561
Anatomy of
base skull 567
pharynx 567
Anemia 277, 594
Anesthesia for
abdominal
sepsis 190
trauma 508
acute spine injury 473
cardioversion 160, 163
cerebrovascular emergencies 432
emergency
Blalock-Taussig shunt 136
cesarean section 235
craniotomy 420
endovascular aortic repair 153
lower extremity revascularization 154
microvascular surgeries 579
myocardial revascularization 103
pulmonary embolectomy 156
renal transplant 588
surgery 34
thoracoabdominal aorta repair 151
valvular heart procedure 120
vascular surgery 147
head injuries 451
hemorrhagic obstetric patient 250
injection of bleeding esophageal varices 217
intestinal obstruction 171
maxillofacial and upper airway trauma 565
neonatal and pediatric 345
neurosurgical decompression 411
ophthalmic emergencies 402
patients with crush injury 538
pelvic and long bone fractures 527
post-tonsillectomy bleeding patient 371
pregnant patient with medical disorders 265
thoracic trauma 488
Anorectal
injury 530
malformation 363
Antepartum hemorrhage 251, 254
Anteriorly fixed larynx 562
Anteroposterior radiograph of pelvis fracture 531
Antibiotic therapy 200, 214
Antifibrinolytic drugs 92
Antiplatelet therapy 39
Anxiolysis 230
Aortic
cross-clamping 148
insufficiency in pregnancy 132
occlusion and reperfusion 148
regurgitation 44, 270
stenosis 44, 126, 269
in pregnancy 132
unclamping 148
Aortocaval compression 230
Apneic oxygenation 395
Arterial air embolism 549
Arteriovenous malformation 439
Ascites 50
Aspiration prophylaxis 230, 236
Aspirin 212
Asthma 274
in pregnancy 275
Atracurium 68
Atresia 359
Auditory system 551
Awake intubation 483
B
Balloon tamponade 214
Benzodiazepines 76
Bicarbonate ions 352
Bilateral cerebral contusions 455
Blast
injury 615
lung injury 549
Bleed classification uses five criteria 209
Bleeding diathesis 594
Blood
and blood component therapy in emergency anesthesia 80
and fluid requirement 563
component therapy 88
pressure
and fluid management 463
management 424
viscosity 415
warmers 85
Blunt
cardiac
injury 495
trauma 155
injury 568
Brain
death 590
monitoring 419
protection 438
relaxation 438
tissue oxygenation 420
Brainstem reflexes 591
Breathing 559
Bronchial foreign body 394
obstruction 389, 391
Bronchodilator therapy 615
Bronchoscopy 390
Buprenorphine 75
Burns 555, 556
Butorphanol 75
C
Cadaveric kidney transplantation 589
Calcium and phosphate metabolism 596
Carbon dioxide 414
Cardiac
surgery during pregnancy 234
trauma and great vessel injury 155
Cardiogenic shock 116
Cardiothoracic trauma 499, 502, 503
Cardiovascular
diseases 266
system 176, 194, 225, 304, 598
Cardioversion and defibrillation in pregnancy 165
Central
nervous system 176, 242, 551, 596
regional blocks 15
Cerebral
abscesses 428
blood flow 414
edema 413
herniation 413
ischemia 416, 417
metabolism 413
microdialysis 420
protection 418
vasospasm 434
venous
infarct 445
thrombosis 445
Cerebrovascular disease 598
Cervical
cerclage 232
spine 534
control 558
immobilization 477
injury 482, 483
Cesarean
delivery 255
section 132, 276
Chest
injury 524
radiograph 140
X-ray 127, 129
Child-Pugh's grading of chronic liver disease 213
Chloride ions 352
Choanal atresia 318
Choice of
anesthesia for cesarean section 245
anesthetic
agents for emergency surgery 54
drugs 13
technique 11, 28
drugs to facilitate intubation 461
ionotropes/vasopressors/ vasodilators 115
Cholinesterase inhibitors 68, 70
Chronic
bronchitis 45
hypertension 240
obstructive pulmonary disease 45
renal failure 29
Cisatracurium 68
Classification of
explosive 547
preeclampsia 241
Clopidogrel 212
Coarctation of aorta 266
Coexisting medical diseases 11
Colloids 199
Colonoscopic hemostatic techniques 216
Combined
mechanical injury 529
spinal and epidural analgesia 244
Common
blast injuries: 615
types of eye injury 403
Compartment syndrome 535, 541
Compatible intravenous fluids 85
Complete
blood count 140
obstruction 389
Complicated myocardial infarction 105
Complications of
deep neck infections 381
immunosuppressant 604
SAH 433
shunt surgery 145
Computerized tomography scan 512
Congenital
diaphragmatic hernia 322, 325
heart disease 266, 355
hypertrophic pyloric stenosis 351
lobar emphysema 337
Continuous epidural analgesia 536
Contraindications for cadaveric organ donation 589
Control of
blood pressure 437, 582
breathing 305
carbon dioxide 582
hemorrhage 573
pain 584
Cricopharynx in child 399
Crush injury 539, 541
Crystalloids 199
CT scan abdomen 181
D
Damage control
surgery 522
thoracotomy 496
Decompressive craniectomy 445
Deep
hypothermic circulatory arrest 152
neck
infections 377
space infections 377
vein thrombosis 535
Definition of
disaster 607
emergency surgery 4
urgent surgery 4
Depressed fracture skull 453
Desflurane 63
Diabetes mellitus 25, 149, 286, 599
Diagnostic peritoneal lavage 512
Diaphragmatic
eventration 498
trauma 497
Different disaster zones 616
Direct laryngoscopic intubation 482
Disaster activation plan 608
Disposal of equipment 86
Distal convoluted tubule 352
Donor kidney 593
Double set-up examination 255
Dropped foreign body 397
Duodenal atresia 359
E
Early endoscopic intervention 211
ECG 127, 129
Ectopic pregnancy 251
Edematous bowel 349
Edrophonium 69
Eisenmenger syndrome 267
Electrocardiogram 140, 436
Electroconvulsive shock therapy 234
Electrolyte requirements 315
Emergency
abdominal aorta repair 149
anesthesia 62, 63
cesarean section 236
department trauma team 612
room care 580
supplies stock 609
surgeries in burns 561
transvenous pulmonary embolectomy 157
End stage renal disease 594
Endoscopic therapy 212
Endoscopy 207
Epidural
analgesia 244
anesthesia 237, 254
hematoma 454
Esophageal
atresia and tracheoesophageal fistula 330
rupture 498
Estimation of blood loss 260
Etiology of hypertension 33
Etomidate 59
Evoked potential monitoring 426
Exomphalos major 347
Expanded criteria donor 589
Explosion physics 547
F
Face and base skull 566
Facial
bones 566
fractures 570
Factors affecting CBF 414
Failed intubation drill 233
Fascial spaces of neck 378
Fat embolism syndrome 535
Fentanyl 73
Fetal
monitoring 231
surgery 328
Fetoplacental unit 242
Fixation of pelvic 532
Flail chest 492, 493
Fluid and
blood transfusion 501
electrolyte
disturbances 596
imbalances 435
management 315
Fluid balance and blood loss 583
Focused assessment sonography in trauma 512
Foreign body
aspiration 389
in upper digestive tract 398
Formulation of command nucleus 610
Fracture
base skull 570
facial bones 568
ribs 492
Full stomach 534
G
Gastrointestinal
bleeding 206, 211
changes 279
system 195, 308, 550, 595
Gastroschisis 347, 349
Genioglossus muscle 378
Geniohyoid muscle and fascia 378
Genital trauma 259
Genitourinary trauma 510
Gestational trophoblastic disease 252
H
Halothane 62
Head
and cervical spine injuries 570
injury 452, 524, 458
trauma 456
Heart rate 123, 125, 129
HELLP syndrome 240, 248
Hematemesis 207
Hematochezia 207
Hemorrhage
in early pregnancy 251
on anesthetic drugs 518
Hemorrhagic shock 513
Hepatic disease 290
Hioglossus muscle 378
Histamine release and itching 72
Human immunodeficiency virus 295
Hydrocephalus 435
Hydrogen ions 352
Hydroxymethylglutaryl-coenzyme reductase inhibitors therapy 39
Hypercyanotic spells 141
Hypertension 33
Hyperthyroidism 283
Hypotension 501, 520
Hypothermia 438, 501, 534
Hypothyroidism 284
Hypovolemia 513
Hypoxemia 501
I
Ileus 180
In utero fetal resuscitation 235
Infective endocarditis 269
Infusion rate devices 85
Inpatient trauma team 613
Intermediate-acting drugs 67
Internal
carotid artery 378
jugular vein 378
Intestinal
malrotation with volvulus 362
strangulation 179
Intracerebral hemorrhage with midline shift 442
Intracompartmental pressures 541
Intracranial
abscess 429
aneurysms 432
hypertension 412, 435
pressure 412, 415
monitoring 412
volume curve 412
Intrahepatic cholestasis of pregnancy 289
Intraocular pressure 403
Intraoperative
blood salvage 91
bronchospasm 47
hemodynamic monitoring 150
monitoring of spinal cord function 485
rupture of aneurysm 438
Intravenous induction agents 55
Iron deficiency anemia 277
Ischemia times 593
Ischemic
heart disease 36
injury 419
Isoflurane 62
J
Jejunoileal atresia 359
Jugular venous
oximetry 420
oxygen saturation 466
K
Ketamine 58
Kidney recipient 593
L
Large gauge intravenous access 236
Laryngeal
foreign body 393
injury 490
mask airway 483
Lateral
compression injury 529, 532
pharyngeal
abscess 379
space 379
Le Fort fractures 569
Left
heart bypass 152
to right shunts 266
Liver 308
cirrhosis 218
disease 48
function tests 49
injuries 509
Living
nonrelated kidney transplantation 589
related kidney transplantation 589
Local
anesthetic techniques 317
control of blood flow 581
Long bone fractures 530, 532
Loss of cervical lordosis 382
Lower gastrointestinal bleeding 215
Ludwig's angina 380
Lumbar epidural anesthesia 280
Lung volume 279
M
Magnesium therapy 247
Major blood loss 534
Malaria 294
Management of
acute
oliguria during perioperative period 32
stroke 444
variceal upper gastrointestinal bleeding 213
airway 385
bleeding varices 215
blood loss 520
disseminated intravascular coagulation 261
hemorrhagic shock 260
nonvariceal upper gastrointestinal bleeding 211
post MI complications 116
pulmonary
edema 246
hemorrhage 158
resistant arrhythmias 164
tight brain 425
Mandibular fractures 569
Mass casualty disasters 607
Massive
blood transfusion 86
hemothorax 494
Maternal
carbon dioxide and acid-base status 228
oxygenation 228
response to hemorrhage 259
Maxillofacial
fractures 569
structures 566
Mechanism of
injury in blast 548
spinal cord injuries 474
Meconium ileus 360
Megaloblastic anemia 278
Metabolic
acidosis 597
substances 415
Methylmethacrylate cement 534
Midazolam 77
Mitigation 610
Mitral
regurgitation 43, 273
regurgitation in pregnancy 132
stenosis 43, 121, 271
in pregnancy 131
valve
prolapse 274
stenosis 122
Mivacurium 66
Mixed valve lesions 130
Model for end-stage liver disease score 49
Modified Blalock-Taussig shunt 144
Monitored anesthesia care 41, 254, 440, 554
Monitoring injured brain 466
Morphine sulphate 76
Muscle relaxants 114, 311, 563
Mylohyoid muscle and fascia 378
Myxedema coma 25
N
Nalbuphine 74
Naloxone 76
Nasotracheal intubation 574
Necrotizing enterocolitis 354
Neonatal thoracic emergencies 321
Neostigmine 69
Nerve block analgesia 536
Neurological injury 530
Neuromuscular blocking agents 64, 227
Nitrous oxide 63, 227
Nonobstetric surgery 229
Nonsteroidal anti-inflammatory drugs 212
Obesity 278
Obstipation 179
Open
fractures 530
pneumothorax 492
pulmonary embolectomy 158
Operating room preparation 142
Operation theater precautions 297
Opioids 70, 311
Oral anticoagulant/antithrombotic therapy 443
Organ
donor card 590
systems 71
Oxygen free radicles 355
P
Palliative systemic-to-pulmonary shunt 137
Parotid gland 378
Partial obstruction 389
Pathophysiology of
chronic renal failure 594
congenital hypertrophic pyloric stenosis 352
crush injury 538
hemorrhagic shock 513
mitral stenosis 121
necrotizing enterocolitis 355
Pediatric emergency surgeries 303
Pelvic
fractures 528
injury 525
open-book fracture 529
ring injury 531
Penetrating
cardiac trauma 156
eye injury 403
injury 455, 568
Pentazocine 75
Percutaneous
coronary intervention 110
intervention 39
Perioperative
analgesia 522
statin therapy 39
Peripheral
nerve plexus block 14
vascular disease 598
Peritoneal dialysis 597
Peritonsillar space 379
Permissive hypotension 514
Personal protective equipment 616
Pharmacologic cardioversion 165
Pharynx 567
Philadelphia collar 477
Physiological sequelae of sepsis 193
Physostigmine 69
Placenta
accreta, increta and percreta 256
previa 254
Platelet activating factor 355
Plmonary function 149
Pneumomediastinum 391
Pneumothorax 391
Poiseuille-Hagan formula 580
Portal hypertension 290
Positive
end expiratory pressure 615
pressure ventilation 394, 395
Posterior fossa space occupying lesions 426
Postoperative
pain management 317
peritonitis 192
ventilation issues 145
Postpartum hemorrhage 251, 258
Post-tonsillectomy bleeding 372
Potassium ions 352
Potential fetal risks 227
Pregnancy
and blast injury 555
on asthma 275
with mitral stenosis 131
Prehospital
fluid resuscitation 612
response service 612
Preoxygenation and cricoid pressure 12
Pressure devices 85
Preterm labor 229
Primary
ACS 523
blast injury 548
head injury 453
injury 475
survey 477
Propofol 56
Prosthetic valve
infective endocarditis 134
valve
leak 133
thrombosis 133
Proximal convoluted tubule 352
Pterygoid internal muscle 378
Pulmonary
artery catheter 126
contusion 492
disease 50
hypoplasia 324
parenchymal injury 615
system 549
thromboembolism 535
vascular
hypertension 324
resistance 123, 126, 128
Q
Quaternary blast injury 551
Quinary blast injury 551
R
Rapacuronium 67
Rapid sequence induction and intubation 184
Regulation of cerebral blood flow 414
Remifentanil 74
Renal
disease 29
in pregnancy 291
dysfunction 50
function 149
ischemia and protection 153
system 176, 194
Repeat endoscopy 212
Replacement of blood and blood components 11
Respiratory system 194, 242, 305
and acid-base balance 224
Resuscitation of
mother 259
spinal cord 479
Resuscitative thoracotomy 496
Retained placenta 258
Retromolar intubation 574
Retropharyngeal
abscess 379, 382
space 379
Return of blood components 86
Reversal of neuromuscular blockade 14
Rhabdomyolysis 541
Right-to-left shunts 267
Rigid bronchoscope 393
Rocuronium 67
Role of
anesthesiologist in
ASCI 476
disaster management 606
management of abdominal sepsis 196
anesthesiology clinical coordinator 610
anesthetist during organ retrieval 592
dextran in microvascular surgery 585
EDTT and IPTT 613
perioperative β-blocker therapy 39
prehospital trauma team 612
regional anesthesia 116, 145, 602
Roundworm
bolus 365
obstruction 365
Rule of nine 556
S
Secondary
ACS 524
blast injury 551
brain injury 455
survey 479, 561
Sengstaken-Blakemore tube 214
Severe spinal cord damage 480
Sevoflurane 60
Sickle cell disease 278
Signs of
airway obstruction 47
MS 122
Simple aortic cross-clamping 151
Sodium ions 352
Spinal
anesthesia for LSCS 280
column dislocation 475
cord
decompressions 429
ischemia and protection 153
Spine injury 479
Splenic injuries 509
Spontaneous
abortion 253
intracerebral hemorrhage 441
ventilation 394
Stabilization of hemodynamic status 540
Stomach and small bowel injuries 510
Strangulated intestinal obstruction 172
Subacute endocarditis 269
Subarachnoid block 237
Subdural
empyema 429
hematoma 454
Submandibular space 380
Submental intubation 574
Succinylcholine 64
Sufentanil 73
Sugammadex 70
Superior pharyngeal constrictor muscle 378
Supine hypotension syndrome 225
Systemic inflammatory response syndrome 115
T
Tension pneumothorax 491
Teratogenicity 226
Tertiary blast injury 551
Tetralogy of Fallot 267
Thiopentone 55
Three column concept of vertebral column 475
Thyroid
disease 20
disorders 282
hormone physiology 282
storm 22
Timing of
endoscopy 211, 216
surgery 229, 327
surgical intervention 481
Tracheal extubation 522
Tracheobronchial injuries 491
Tracheotomy 573
Tramadol 74
Tranexamic acid 212
Transesophageal echocardiography 126
Transvenous cardioversion 165
Trauma score system 613
Traumatic
amputation 530
aortic injury 496
Treatment of
GI bleeding 211
hyperkalemia 540
myxedema coma 25
septic abortion 253
shock 260
various electrolyte abnormalities 7
Tumor necrosis factor 355
Types of
bronchial obstruction 389
cerebral herniation 413
disaster 607
ophthalmologic emergencies 402
pelvic fractures 528
renal transplantation 589
shunts 137
surgery 224
U
Ultrasonography 150, 333
Upper
airway trauma 572
and lower gastrointestinal bleeding 207
gastrointestinal bleeding 207
Urogenital injury 529
Use of
antiemetics 236
oxytocic drugs 236
vasopressors and inotropes 200
Uterine
atony 258, 259
inversion 258
rupture 257
Uteroplacental perfusion and fetal oxygenation 228
V
Vaginal delivery 244
Valvular heart disease 41, 120, 133, 269
Variceal rebleeding 215
Vasa previa 257
Vascular injuries 510
Vasoactive drug and endoscopic therapy 215
Vecuronium 67
Ventilating bronchoscope 395
Ventricular septal rupture 116
Venturi injector device 396
Vertical shear injury 529, 532
Video assisted thoracoscopic surgery 498
Viral hepatitis 288
Volume of resuscitation 199
W
Wake up test 485
Widened mediastinum 497
X
X-ray abdomen in
duodenal atresia 359
meconium ileus 362
necrotizing enterocolitis 356
X-ray chest and abdomen 332, 333
Z
Zones
in neck 568
of injury 417
×
Chapter Notes

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1General Considerations

General Principles for Emergency Anesthesia1

Manju N Gandhi,
Kanchan R Rupwate,
Kamlesh G Gotiwale,
Manish B Kotwani
 
INTRODUCTION
Anesthesia for emergency situation can be termed as unplanned as the patients are not evaluated preoperatively and prepared for the surgery. This situations can occur anywhere inside the operation theater or outside the comfort of operation theater including ICU, high dependency units, coronary care units, fields and war situations.
 
DEFINITION OF EMERGENCY SURGERY
Immediate operation is needed usually within one hour of surgical consultation to save life. Resuscitation of patient is performed simultaneously with surgical management. Emergency cases require a great deal of logistical coordination between surgeons, anesthesiologists and various other disciplines of medicine. Emergency operations take precedence over all other cases and anesthesia is sometime administered in desperate circumstances, e.g. major thoracic, abdominal trauma, cardiac tamponade, major vessel trauma, obstetric emergencies.
The time available to accomplish this task is short and patient's condition may deteriorate rapidly. Therefore both decision-making and performance may be compromised in such circumstances.
In certain situations, the patient may need to be transferred to tertiary care centre, then one must ensure that optimal care is provided during evaluation, resuscitation and transfer process.1
 
DEFINITION OF URGENT SURGERY
The operation needs to be performed as soon as possible. The surgery can be differed for few hours to up to 24 hours, thereby one gets time for resuscitation and hemodynamic optimization of the patient, e.g. facial fractures without active nasal/oral bleeding, closed long bone fractures, etc.
 
ENVIRONMENT CONSIDERATION AND PREPAREDNESS
Emergency anesthesia is given in several environments. In prehospital emergency situations, either paramedics or emergency physicians are responsible for airway instrumentation and sedation/anesthesia, depending on the country and organization.
All anesthesiologists have to handle life-threatening crisis without any warning. However, some cognitive strategies and work practices that are appropriate for speed and efficiency under normal circumstances may become maladaptive in a crisis situation. It could be due to stress during high-risk patient management and suboptimal facilities available at that point of time.5
The use of structured ‘core’ algorithm (based on mnemonic COVER ABCD A SWIFT CHECK) would diagnose and correct the problem in 60 percent of cases and provide a functional diagnosis in remaining 40 percent of cases.2
 
PREOPERATIVE ASSESSMENT
Once the decision has been made to proceed with operative management, a number of considerations must be addressed regarding the timing and site of surgery, the type of anesthesia, and the preoperative preparation necessary to optimize the patient. Direct communication with the consultant and with the patient's primary care provider, whenever possible, may provide meaningful clinical information.
By definition, emergency induction is needed when acuity of the patient's presentation does not allow anesthesiologist the normal preoperative assessment and optimization. The emergency patient is at higher risk for anesthesia and surgery in almost all surgical circumstances.
At bare minimum, one needs to have answers to the following questions:
  • Why patient needs emergency surgery?
  • How much time is available for resuscitation?
  • Are there are signs indicating presence of hemorrhage?
  • What are the results of quick airway assessment for difficult intubation?
  • Whether patient will need ventilatory support postoperatively, ICU care, etc.?
A quick look at patient's history, records, ease of intubation, investigations like hematocrit, serum creatinine, blood glucose, coagulation status, arterial blood gas analysis and electrolytes may give rough estimation of patient's condition. Predicting anatomically difficult airway in a patient with critical condition is more difficult than in patient having an elective surgical operation. In addition the position of patient, facial and neck injuries, full stomach, saliva, blood and debris in the upper airway may worsen the intubating conditions and sometimes even makes it impossible to intubate the patient.
The anesthesiologist decides when the patient has recovered enough to be sent to a regular room, High dependency unit (HDU) or transferred to an intensive care unit (ICU). Mandating an ICU stay in advance makes no sense unless the operation itself demands ICU care.3 In case of hemodynamically unstable patient, cardiac surgery, neurosurgery or septicemic patient, etc. who may need ICU care, the concerned department should be informed preoperatively for necessary arrangement.
 
EMERGENCY INVESTIGATIONS
Certain bedside investigations that can ascertain lot of required information like hemoglobin, blood glucose with glucometer/or glucose strips, urine ketones with ketostix, arterial blood gases with serum electrolytes, electrocardiogram (ECG) and portable X-ray’ can be availed within short period of time.
Blood should be send for grouping and crossmatching as and when required. If requirement of more number of blood and blood products is anticipated, the blood bank should be alerted as soon as possible.
In addition, portable ultrasonography can be used for surgical diagnosis, portable 2-dimensional echocardiography for cardiovascular evaluation and thromboelastography (TEG) for determination of bleeding disorders.
Whenever the surgery is urgent or semiurgent, detailed investigations can be performed within few hours.
 
PREANESTHETIC PREPARATION
For many patients optimal perioperative care may require little or no additional medical management beyond that given by the anesthesiologist and surgeon. However, there is a continued existence of a group of surgical patients who are at a high-risk of morbidity and mortality which indicate an ongoing need to identify such patients and deliver optimal care throughout the perioperative period.
A group of patients may exist in whom the risk for death and serious complications after major surgery is in excess of 20 percent. The risk is related mainly to the patient's preoperative physiological condition and, in particular, the cardiovascular and respiratory reserves.4
The medical management of all co-existing disease processes should then be reviewed to ensure that current standards of best practice are adhered to. Various aspects of perioperative management should then be given consideration. It is recommended that all such patients be admitted to a critical care area ideally before surgery. There is evidence to suggest that this approach results in an overall reduction in consumption of resources.5,6
Certain special group of patients should be cared as per their co-existing diseases or physiologic alterations due to various reasons. Some of them are like neonates, pediatric patients, geriatric patients, obstetric patients, neurosurgical patients, cardiac surgery patients, motor 6vehicular trauma victims and patient coming for cadaveric organ transplantation, etc. may need specialized care.
 
Preoperative Optimization and Management of Complications
Preoperative optimization is a vital component of safe conduct of anesthesia. The risk of operation can often be lowered by treatment of physiological derangements like hypoxia, hypoventilation, hypovolaemia, dehydration, acidosis/alkalosis, electrolyte abnormalities and control of blood glucose levels, etc.
Most of the patients who need emergency anesthesia outside the operation theatre have serious disturbances in respiratory and/or hemodynamic function. Anesthetic agents may worsen these disturbances.
Thus the following underlying conditions should be treated simultaneously with induction of anesthesia and intubation.
  • Predict the problems like hypoxia and correct it with preoxygenation
  • Manage hypotension with fluids and vasoactive drugs
  • Aspiration prophylaxis for vomiting and regurgitation should be managed with rapid sequence intubation using cricoids pressure and using suction device whenever patient vomits
  • Correct acidosis and electrolyte abnormalities
  • Maintain effective circulatory blood volume to prevent inadequate tissue perfusion
  • Cardiac arrhythmias are to be managed with drugs and defibrillator.
The appropriate administration of intravenous fluid therapy to maintain an effective circulating volume and prevent inadequate tissue perfusion is a core element of the perioperative practice of anesthesia. The choice of fluids in a variety of different clinical situations can now be rationally guided by an understanding of the physiochemical and biological properties of the crystalloid and colloid solutions available.
There is no difference in outcome between crystalloid or colloid administration when the amount infused is 3 to 4 liters but when volume of crystalloid infused reaches more than patient's blood volume there may be cellular edema. Therefore, it is wise to use balanced combination of crystalloid and colloid as per patient's requirement. However, one must be careful while giving colloids, especially when it is infused while waiting for blood to arrive. If the blood is transfuse as soon as it arrives and colloids still circulating in intravascular compartment at that point of time, it may lead to pulmonary congestion especially in geriatric patients.
Goal-directed “optimization” of intravascular volume and organ blood flow aims to ensure adequate tissue perfusion and cellular oxygenation. There is a substantial body of literature demonstrating that mortality following major surgery can be significantly reduced by goal-directed approaches to perioperative hemodynamic management.
Perioperatively patients may be ‘water and solute depleted’ owing to:
  • Decreased intake (preoperative fasting, anorexia, altered consciousness level)
  • Increased losses (vomiting, diarrhea, pyrexia, bleeding)
  • In addition intraoperatively, both anesthesia and the surgical procedure may upset the fluid balance
  • Intravenous and inhalational anesthetic agents commonly produce relative hypovolemia secondary to vasodilatation, and act as myocardial depressants, reducing cardiac output
  • Surgical losses include direct hemorrhage, evaporative losses from exposed mucosal surfaces and third-space losses.
The traditional approach of an “X” ml/kg continuous fluid infusion with additional replacement of observed losses is clearly flawed in major surgery. It takes no account of preoperative fluid status.
Fluid therapy should be titrated to rational physiological end-points:
  • Pulse, blood pressure
  • Skin turgor, absence of thirst, etc.
  • Monitoring of central venous pressure and whenever possible pulmonary capillary wedge pressure can be used to guide fluid therapy in critically ill patient.
One must not forget the ultimate goal of fluid therapy is maintenance of tissue perfusion and oxygenation.
In the study of fluid therapy for ambulatory surgery, it is suggested that preoperative or intraoperative crystalloid infusion of 20 ml/kg improves clinical outcome. In particular, postoperative nausea and vomiting is reduced following intraoperative crystalloid infusion, when compared with controls.7
Recently distinct sets of goals have been employed for fluid optimization:
  • Intravascular pressure measurements (arterial pressure, central venous pressure, and pulmonary artery occlusion pressure)7
  • Indices of global blood flow (cardiac output or index; stroke volume or index, oxygen delivery, and mixed venous oxygen saturation)8
  • Indices of tissue perfusion (gastrointestinal tonometry, tissue oxygen electrodes)7,11
  • Dynamic ultrasonographic evaluation of the heart and great vessels in prediction of the fluid responsiveness of critical patient has been evaluated9
  • Recent trial of patients recruited in the emergency room with early severe sepsis demonstrated a significant reduction in mortality when SvO2 (from a CVP line) was used to direct therapy10
  • Doppler flowmetry for splanchnic perfusion12 and microdialysis catheters13 have been use for guiding the fluid therapy
  • Near infrared spectrometry14 and tissue pH monitors.
There are now a number of well conducted studies that show that the use of perioperative goal directed therapy may improve outcome.15-18
 
Electrolyte Emergencies, Anion Gap and Osmolality
In the emergency department and acute surgical emergencies anesthesiologist have to deal with various fluid-electrolyte disturbances. Since fluid balance, electrolyte and acid-base derangements share common pathophysiological process, a full understanding of the ongoing interplay of homeostatic derangement and choosing the correct approach to a therapeutic strategy is necessary for the management of the critically ill patient.19
Hyperosmolality is present when plasma osmolality exceeds 295 mOsm/kg and that leads to water shift from ICF to ECF leading to thirst stimulation and ADH release, e.g. hyperosmolar diabetic ketoacidosis. In this case the patient will also tend to have metabolic acidosis, hyponatremia and hyperkalemias. Again because of metabolic acidosis patient will be in respiratory alkalosis. Here the main aim is to correct the hyperglycemia with insulin and dehydration with normal saline.
Hypoosmolality condition can be seen due to overloading or overhydration with crystalloids, hypotonic solution, and in patients with hypoproteinemia, heart failure and liver cirrhosis, etc. One of the major drawback of infusing 5 percent dextrose as replacement solution for major shift in fluid is that once glucose is utilized by the body then what will remain in intravascular compartment is water, which is hypotonic and may lead to tissue or pulmonary edema.
The target organ in any dysosmolal state is brain. As a general rule the faster the onset of disorder, the poorer the prognosis—owing to lack of time to compensate for the disorder at the metabolic and neuronal level. However, it may be possible to tolerate these disturbances provided enough time is elapsed to tolerate the ‘water stress’ that is hyponatremia.
 
Treatment of Various Electrolyte Abnormalities
Treatment of hyponatremia: Hyponatremia is usually asymptomatic unless serum sodium level falls below 120 mEq/L. The hyponatremia is commonly seen in patients with severe vomiting diarrhea, geriatric patient, TURP syndrome, burns, diabetic ketoacidosis and cerebral salt wasting syndrome.
Treatment of hyponatremia involves the administration of sodium and elimination of free water. Correction of hyponatremia should be gradual, usually an increase of 0.5 mEq/L/hr and to maximum of 10 to 15 mEq/L in first 24 hr. Rapid correction of serum sodium can cause pontine myelinosis, a lethal disorder caused by rapid shift of fluid in the brain. In hyponatremic states a loop diuretic can be given with hypertonic saline infusion, to enhance free water clearance. If serum sodium is above 120 to 124 mEq/L, it can be corrected slowly with 0.9 percent solution and loop diuretic furosemide injection. Whenever serum sodium is below 118 mEq/L then patient should be treated with 3 percent sodium chloride (513 Na+ mEq/L) till serum sodium concentration is above 120 mEq/L or neurological symptoms improves. Check serum electrolyte frequently.
Ultimate correction of serum sodium requires calculation of the sodium deficit. The following formula can be used:
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Treatment of hypernatremia: Hypernatremia is defined as a serum sodium concentration above 145 mEq/L. Hypernatremia may be caused by a primary Na+ gain or excess water loss. A common cause of hypernatremia is free water loss in excess of sodium loss, such as that which occurs with diabetes insipidus or hypernatremic dehydration. In the brain, decreased nerve cell volume can cause neurological symptoms, including altered mental status, weakness, irritability, focal neurological deficits, and even coma or seizures.8
To treat hypernatremia, it is important to stop ongoing water losses (by treating the underlying cause) while correcting the water deficit. In hypovolemic patients the extracellular fluid (ECF) volume must be restored with normal saline.
The quantity of water in liters required to correct hypernatremia can be calculated by the following equation:
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Once the free water deficit is calculated, administer fluid to lower serum sodium at the rate of 0.5 to 1.0 mEq/L/hr with a decrease of no more than 12 mEq in the first 24 hours. Total correction should be achieved over 48 to 72 hours. The method of replacement of free water depends on the patient's clinical status. For stable, asymptomatic patients, replacement of fluid by mouth or through a nasogastric tube is effective and safe. If this is not possible or if the patient's clinical status demands more aggressive treatment, 5 percent dextrose in half-normal saline may be given IV. Check the patient's serum sodium and neurological function frequently to avoid overtly rapid correction.
Treatment of hypokalemia: Hypokalemia is defined as a serum potassium level <3.5 mEq/L. Hypokalemia results from one or more of the following reasons: decreased dietary intake, shift into cells, or increased net loss from the body. The most common causes of low serum potassium include gastrointestinal loss (diarrhea, laxatives), renal loss (hyperaldosteronism, potassium-losing diuretics, intracellular shift (alkalosis or a rise in pH) and malnutrition.
Symptoms of hypokalemia include weakness, fatigue, paralysis, respiratory difficulty, muscle pain, constipation, paralytic ileus, and leg cramps. Hypokalemia also exacerbates digitalis toxicity.
ECG changes suggestive of hypokalemia includes:
  • U waves
  • T-wave flattening
  • ST-segment changes
  • Arrhythmias (especially if the patient is taking digoxin)
  • Pulseless electrical activity (PEA) or asystole.
The treatment of hypokalemia includes minimizing further potassium loss and giving potassium replacement. Intravenous administration of potassium is indicated when arrhythmias are present or hypokalemia is severe (K+ <2.5 mEq/L). Rate of infusion of potassium chloride should be guided by ECG and serum electrolyte determination. Before starting the intravenous infusion of potassium one must ensure that the urine output is adequate.
The potassium deficit is calculated according to the following formula:
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Concentrated potassium solution is for IV admixtures only; do not use undiluted. Direct injection may be instantaneously fatal.
Suitable vehicle solutions, e.g. 5 or 10 percent glucose solutions, isotonic sodium chloride solution, compound sodium lactate solution.
  • The potassium concentration in the infusion solution must not exceed 40 mEq/L
  • Do not infuse rapidly. Maximum infusion rate: Up to 40 mEq potassium per hour (corresponding to 0.3 m Eq potassium/kg body weight/hour) in adults when the serum potassium is below 2 mEq/L
  • Maximum daily dose should not exceed more than 2-3 mEq/kg body weight/day
  • Children: IV infusion up to 3 mEq/kg/day. Adjust volume of administered fluids to body size
  • In critical states, potassium chloride may be administered in saline (unless saline is contraindicated), since dextrose may lower serum potassium levels by producing an intracellular shift along with glucose
  • As a matter of principle, infusion pumps should be used for the infusion of potassium.
If cardiac arrest from hypokalemia is imminent (i.e. malignant ventricular arrhythmias), rapid replacement of potassium is required. Give an initial infusion of 2 m Eq/min, followed by another 10 mEq intravenously after 10 minutes. Once the patient is stabilized, reduce the infusion to continue potassium replacement more gradually.
Treatment of hyperkalemia hyperkalemia (potassium >5.5 mEq/L) is common finding in patient with acute or chronic renal failure, oral/parenteral potassium supplementation and patients on angiotensin converting enzyme inhibitors (ACEI) or potassium sparing diuretic (Spironolactone). The hyperkalemia may also develop following succinylcholine in patients with severe burns, lower motor neuron paralysis or spinal cord trauma with paraplegia or quadriplegia. This is also observed in cases of crush injury, compartment syndrome, rhabdomyolysis or following tourniquet release, etc.9
Changes in pH inversely affect serum potassium. Acidosis (low pH) leads to an extracellular shift of potassium, thus raising serum potassium. Conversely, high pH (alkalosis) shifts potassium back into the cell, lowering serum potassium.
Physical symptoms of hyperkalemia include, weakness, ascending paralysis, and respiratory failure. ECG changes suggestive of hyperkalemia include:
  • Peaked T waves (tenting)
  • Flattened P waves
  • Prolonged PR interval (first-degree heart block)
  • Widened QRS complex
  • Deepened S waves and merging of S and T waves
  • Idioventricular rhythm
  • Sine-wave formation
  • VF and cardiac arrest.
Emergency treatment of hyperkalemia may include any of the following measures:
  • Discontinue medications that increase blood potassium levels
  • Intravenous administration of glucose and insulin, which promotes movement of potassium from the extracellular space back into the cells. Mix 50 gm glucose and 10 U regular insulin and give IV over 15 to 30 minutes
  • Intravenous calcium to temporarily protect the heart and muscles from the effects of hyperkalemia. (Calcium Chloride/Gluconate 10 cc of 10 percent over 2 to 5 min)
  • Sodium bicarbonate administration to counteract acidosis and to promote movement of potassium from the extracellular space back into the cells (50 to 100 mEq over 5 min)
  • Diuretic administration to decrease the total potassium stores through increasing potassium excretion in the urine, e.g. furosemide 1 mg/kg IV slowly
  • Medications that stimulate beta-2 adrenergic receptors, such as albuterol and epinephrine have also been used to drive potassium back into cells
  • Nebulized albuterol 10 to 20 mg nebulized over 15 minutes.
  • Medications known as cation-exchange resins, which bind potassium and lead to its excretion via the gastrointestinal tract. Resins—Kayexalate 15 to 30 g in 50 to 100 ml of 20 percent sorbitol either orally or by retention enema (50 g of Kayexalate)
  • Dialysis, particularly if other measures have failed or if renal failure is present.
Treatment of hyperkalemia naturally also includes treatment of any underlying causes (e.g. kidney disease, adrenal disease and tissue destruction) of hyperkalemia.
Treatment of hypomagnesemia: Hypomagnesemia is far more common clinically than hypermagnesemia. Defined as a serum magnesium concentration below the normal range of 1.3 to 2.2 mEq/L, hypomagnesemia usually results from decreased absorption or increased loss, either from the kidneys or intestines (diarrhea). Alterations in parathyroid hormone and certain medications (e.g. diuretics, alcohol) can also induce hypomagnesemia.
Symptoms of low serum magnesium include muscular tremors and fasciculations, ocular nystagmus, tetany, and altered mentation. Other possible symptoms include ataxia, vertigo, seizures, and dysphagia. A number of ECG abnormalities occur with low magnesium levels, including:
  • Prolonged QT and PR intervals
  • ST-segment depression
  • T-wave inversion
  • Flattening or inversion of precordial P waves. Widening of QRS
  • Torsades de pointes ventricular arrhythmias Resistant VF (and other arrhythmias)
  • Worsening of digitalis toxicity
  • Treatment of hypomagnesemia depends on its severity and the patient's clinical status
  • For severe or symptomatic hypomagnesemia, administer 1 to 2 g IV MgSO4 over 15 minutes
  • If torsades de pointes ventricular arrhythmias are present, administer 2 g of MgSO4 over 1 to 2 minutes
  • If seizures are present, administer 2 g IV MgSO4 over 10 minutes
  • Risks involved with intravenous magnesium therapy include hypermagnesemia, hypocalcemia, and sudden hypotension.
Treatment of hypermagnesemia: Magnesium balance is influenced by many of the same regulatory systems that control calcium balance. In addition, magnesium balance is influenced by diseases and factors that control serum potassium. As a result, magnesium balance is closely tied to both calcium and potassium balance.
The most common cause of hypermagnesemia is renal failure. Hypermagnesemia may also be iatrogenic (caused by overuse of magnesium) or caused by a perforated viscus with continued intake of food and use of laxatives/antacids containing magnesium.
The signs and symptoms are neurological symptoms like lethargy, muscular weakness, paralysis, ataxia, drowsiness, and confusion. Gastrointestinal symptoms include nausea and vomiting. Moderate hypermagnesemia can produce vasodilation, and severe hypermagnesaemia can produce hypotension. Extremely high serum magnesium levels may produce a 10depressed level of consciousness, bradycardia, hypoventilation, and cardiorespiratory arrest.
ECG changes of hypermagnesemia include:
  • Increased PR and QT intervals
  • Increased QRS duration
  • Variable decrease in P wave voltage
  • Variable degree of T wave peaking
  • Complete AV block, asystole.
Hypermagnesemia is treated by antagonizing magnesium with calcium gluconate/chloride, removing magnesium from serum, and eliminating sources of ongoing magnesium intake. Cardiorespiratory support may be needed until magnesium levels are reduced. Administration of calcium chloride (10 cc of 10 percent) intravenously will often correct lethal arrhythmias.
Dialysis is the treatment of choice for treatment of severe hypermagnesemia.
Treatment of hypocalcemia: Hypocalcemia is defined as a serum calcium concentration below the normal range of 8.5 to 10.5 mg/dl (or an ionized calcium below the range of 4.2 to 4.8 mg/dl). Hypocalcemia may develop with toxic shock syndrome, abnormalities in serum magnesium and tumor lysis syndrome. Symptoms of hypocalcemia usually occur when ionized levels fall below 2.5 mg/dl. Symptoms include paresthesias of the extremities and face, followed by muscle cramps, carpopedal spasm, stridor, tetany, and seizures. Hypocalcemic patients demonstrate hyperreflexia and positive Chvostek and Trousseau signs. Cardiac symptoms include decreased contractility and heart failure. Hypocalcemia can exacerbate digitalis toxicity.
ECG changes of hypocalcaemia include following:
  • QT-interval prolongation
  • Terminal T wave inversion
  • Heart blocks
  • Ventricular fibrillation.
Treatment of hypocalcemia requires administration of calcium. One ampoule of calcium chloride is equal to three ampoules of calcium gluconate. Treat acute symptomatic hypocalcemia with 10 to 20 cc of 10 percent calcium gluconate (90 to 180 mg of elemental calcium) IV over 10 minutes. Follow this with an IV drip of 540 to 720 mg of elemental calcium in 500 to 1000 ml D5W 0.5 to 2.0 mg/kg per hour (10–15 mg/kg). Measure serum calcium every 4 to 6 hours and aim to maintain the total serum calcium concentration between 7 and 9 mg/dl.
Treatment of hypercalcemia: Hypercalcemia is defined as a serum calcium concentration above the normal range of 8.5 to 10.5 mg/dl (or an elevation in ionized calcium above 4.2–4.8 mg/dl). Symptoms of hypercalcemia usually develop when the total serum calcium concentration reaches or exceeds 12 to 15 mg/dl. Neurological symptoms include depression, weakness, fatigue, and confusion at lower levels. At higher levels patients may exhibit hallucinations, disorientation, hypotonicity, and coma. Hypercalcemia interferes with renal concentration of urine, causing dehydration.
Cardiovascular symptoms of elevated calcium levels are variable. Myocardial contractility may initially increase until the calcium level reaches 15 to 20 mg/dl. Above this level myocardial depression occurs. Automaticity is decreased and ventricular systole is shortened. Arrhythmias occur because the refractory period is shortened. Digitalis toxicity is worsened. Hypertension is common. In addition, many patients with hypercalcemia develop hypokalemia; both these conditions contribute to cardiac arrhythmias. Hemodialysis is the treatment of choice to rapidly decrease serum calcium in patients with heart failure or renal insufficiency. Chelating agents may be used for extreme conditions (e.g. 50 mmol PO4 over 8–12 hours or EDTA 10–50 mg/kg over 4 hours).
Abnormalities in sodium, potassium, calcium, magnesium and pH must be corrected simultaneously.20
 
Preemptive Managment to prevent Postoperative Acute Deterioration in Renal Function
Postoperative acute deterioration in renal function producing oliguria and/or increase in serum creatinine is one of the most serious complications in surgical patients. Most cases are due to renal hypoperfusion as a consequence of systemic hypotension, hypovolemia, and cardiac dysfunction. Hence all efforts should be made to identify patients and surgery that would most benefit from perioperative optimization with fluid therapy.21
Postoperative gastrointestinal function is influenced by preoperative fluid optimization, e.g. better splanchnic perfusion and lower gut edema with tetrastarches decrease the incidence of PONV.22,23
 
Selection of IV Fluid
Numerous fluid preparations are available for the replacement of perioperative fluid losses in patients undergoing surgery. The selection of particular fluid is influenced by multiple factors like tradition, systemic effects, postoperative outcome and cost.
Impact of IV fluids on coagulation Whenever small volume is administered (1000 ml), there is no difference in outcome. The administration of large volume of any type of fluid will cause dilution of platelets and coagulation factors which may lead to coagulopathy. In 11addition, fluids can have direct impact on blood clotting through effect on circulating components of coagulation cascade or altering platelet function. Several studies demonstrate hydroxyethyl starches 130/0.4 M and gelatins have fewer adverse effects on coagulation in comparison with higher molecular weight starches.
 
Replacement of Blood and Blood Components
Whenever patient is actively bleeding or has lost more than 30 to 40 percent blood volume and there is anticipation of major blood loss due to nature of surgical procedure, the transfusion of blood should be started as soon as possible. Blood components should be used rationally whenever indicated. The details of this will be dealt in another chapter of this book. Blood and blood products should be arranged as per the need and urgency before induction of anesthesia.
Once, the patient's co-morbidities are optimally managed, whether or not to proceed with surgery is a question for the anesthesiologist, surgeon and patient to decide after weighing the risks and benefits. No specific anesthetic is inherently safer than any other.
 
Coexisting Medical Diseases
Several medical diseases like uncontrolled hypertension, diabetes mellitus, asthma, congestive cardiac failure or other cardiac problems could complicate the course of surgery and anesthesia. Standard care requires that the inter–current medical disease is optimized prior to induction of anesthesia. This is often not possible in emergent situations. It is necessary that attempts should be made at optimizing the medical condition as much as time would allow.
Complicating diseases and conditions may strongly influence the outcome of procedure undertaken. In patients with coronary artery disease, congestive cardiac failure, respiratory failure, pulmonary emphysema, asthma, liver disease, renal disease and diabetes mellitus different methods of therapy and anesthesia must be employed, so that minimal delay without compromising the safety of patient is employed.24
 
Following Equipment and Drugs should be Readily Available
  • Emergency intubation cart: Various sizes of laryngoscopic blades, endotracheal tubes, stylet, different types of laryngoscope, gum-elastic bougies, LMA/ILMA, fiberoptic bronchoscope, percutaneous cricothyroidotomy set or tracheostomy set, etc.
  • A table that can be rapidly placed in head down (Trendelenberg) position: In case of vomiting or regurgitation the patient should be quickly rolled onto one side and the head of the table tipped down, using gravity to facilitate exit of vomitus from the airway and pharynx. Caution patients who have received spinal anesthesia should never be placed head down, even if shocked. The reason is that further shock and respiratory failure may rapidly ensue if the spinal anesthetic agent is allowed to bathe the upper spinal cord during a head-down maneuver. For other patients, there is some debate whether the Trendelenberg position actually helps anyone who is hypotensive.
  • Have suction instantly ready, check equipment before starting
  • Have resuscitation drugs (inotropes, vasopressors and vasodilators) tray ready with plenty of intravenous fluids
  • Patient warming system
  • Monitoring equipment like ECG, pulse oximeter, capnometer, NIBP/IBP, temperature, bispectral index monitor, etc.
  • In special scenario cardiac output monitor, transesophageal echocardiography can be used.
  • CVP/ PCWP for guiding fluid therapy may be used.
  • Urine output should be monitored hourly.
 
Choice of Anesthetic Technique
The anesthetic choice for emergency procedures is guided by the nature of surgical technique and the preferences of the anesthesiologist. They can be:
  • General anesthesia
  • Local anesthesia
  • Central regional anesthesia
    • Peripheral nerve blocks
  • Total intravenous analgesia (Bier's block)
Factors favoring the use of general anesthesia:
  • Hemodynamic instability
  • Uncertainty of diagnosis and duration of surgery
  • Lack of time
  • Patient's distress or confusion
  • Strangulated or obstructed inguinal hernia
  • Septicemic patient
  • Fetal distress, cord prolapsed, uterine rupture, for LSCS.
In some cases either general or regional anesthesia may be administered:
  • Amputation
  • Debridement of wound
  • Drainage of abscesses
  • Fracture of long bones
  • Patients who received general anesthesia for initial surgery due to hemodynamic instability may 12become fit to receive regional anesthesia for subsequent surgery within few days, e.g. wound washing, redo surgery, etc.
Is there a best approach to induction of anesthesia in emergent situation?
Anesthetic agent/or sedative agents should be used judiciously with careful titration. Patients in shock have increased sensitivity to these agents. Sympathetic drive is at its maximum in patient with shock or hemodynamically compromised patient, therefore these patients tend to decompensate at the time of induction. Direct depressant effect of sedative and hypnotic agents may lead to vasodilatation and in addition positive pressure ventilation may reduce cardiac filling, as a result severe hypotension and sometimes cardiac arrest may occur since protection due to sympathetic drive is lost.
The risk of laryngospasm, hemodynamic instability and aspiration at the time of induction should be kept in mind.
The choice of induction agent is less important than the dose selected for particular patient in emergency. Initially full induction dose should not be given in order to prevent severe hypotension. The drug should be given in small aliquots, once the patient tolerates the first small dose well, the additional doses can be supplemented slowly by keeping watch on patient's hemodynamics parameters. Choice of neuromuscular blockade depends on clinical situation.
 
Care during Intubation
Intubation response should be attenuated in traumatic brain injury (TBI) or patients with intracerebral bleed and malignant hypertensive patient, etc. The intubation may be difficult, in patients with maxillofacial trauma and cervical spine injury especially with on line stabilization or cervical traction in place.
 
Full Stomach and Regurgitation Risk
As a general rule, all patients must come to the operating room starved (no solids for 6 hours, water allowed up to 2 hours preoperatively). One should assume that the stomach is not empty in injured or severely ill patients, in those who have received an opiate. Paralytic ileus is common following trauma and in patients with associated major medical diseases, therefore, delaying the anesthesia to allow the stomach to empty may not work. Hence, measures to reduce the risk of aspiration while otherwise proceeding with emergency induction, should be undertaken.25
Any method of anesthesia, including awakening techniques, can have an unexpected reaction that can, in theory, lead to unconsciousness, regurgitation and aspiration of stomach contents. One need to judge each case on its merits, balancing the risk of regurgitation and aspiration against the risks of general or spinal anesthesia. The general condition of the patient determines the risk of regurgitation more than the choice of technique.
Patients with high-risk of pulmonary aspiration of gastric contents or delayed gastric emptying are of following types:
  • Patients with ileus, subileus, and bowel obstruction are considered nonfasting; irrespective of time elapsed since last meal or drink. Insertion of a naso-gastric/duodenal tube in the ward prior to anesthesia induction is mandatory
  • Presence of nasogastric tube itself can lead to regurgitation and aspiration
  • Pregnant women of more than 20 weeks of gestation, including the first 24 hours postoperatively
  • Patients with preoperative nausea/vomiting, e.g. newly started opioid pain treatment
  • Patients with hiatal hernia, gastroesophageal reflux, or nausea or vomiting
  • Morbidly obese patients (BMI > 35)
  • Long standing diabetes mellitus (considering the risk of polyneuropathy and gastroparesis)
  • Recently ingested full meal
Whenever possible, operate on a fasted patient: Aspiration is always possible. However, the risk of not operating is sometimes worse than the risk of aspiration, so the fasting rule is not an absolute one.
The risk of perioperative complications is reduced if patients can achieve the standards outlined below:
  • H2-blocker or proton pump inhibitor used to reduce gastric acidity and volume can reduce the morbidity of aspiration since acid is worse than neutral aspiration.
  • Sodium citrate can be used to reduce acidity.
  • Gastric prokinetic drugs like metoclopramide can be used. However, this should be avoided in intestinal obstruction or perforative peritonitis.
  • Whenever a patient vomits, roll him to the side, drop his head downward, and suction his oropharynx immediately.
 
Preoxygenation and Cricoid Pressure
  • Avoid a leak between the patients face and the oxygen mask
  • Tidal volume breathing for 3 minutes or 8 deep breaths over 60 seconds with an oxygen flow of at least 10 L/min should be used13
  • Using 4 deep breaths over 30 seconds is a less effective procedure
  • Noninvasive positive pressure ventilation or the application of positive end-expiratory pressure can be considered in the morbid obese or the critically ill hypoxic patients
  • Preoxygenation in the obese patients should be performed in the head up position
  • Use of cricoid pressure is not considered mandatory, but can be used on individual judgment
  • Those choosing to use cricoid pressure in the patient at risk of aspiration must take care to apply the cricoid pressure correctly and release the pressure if ventilation or laryngoscopy and intubation prove difficult
  • Cricoid pressure should be released before inserting the laryngeal mask airway (LMA) in case initial attempts at tracheal intubation prove unsuccessful
  • Alternative plan of action should be ready for cannot ventilate cannot intubate (CVCI) situation
  • Nasogastric tubes and the cricoid pressure may cause interference with airway management techniques. Sellick recommended that nasogastric tubes should be removed after final aspiration before induction of anesthesia as they might increase the risk of regurgitation and aspiration by tripping the esophageal sphincters1 since nasogastric tube, occupying the part of the esophageal lumen, is not obliterated by the pressure on cricoid cartilage
  • One may pull up the nasogastric tube in esophagus above the esophageal sphinter thereby making the esophageal sphincter competent. Once the patient is intubated the nasogastric tube can be advanced into the stomach.
 
Choice of Anesthetic Drugs
The induction agents with the most favorable pharmacological properties conferring hemodynamic stability appear to be ketamine and etomidate. Ketamine is traditionally contraindicated in the presence of brain injury. Ketamine represents a very rational choice for rapid sequence induction in hemodynamically compromised patients. If patient is stable any hypnotic drug can be used for induction and maintenance. The introduction of propofol and remifentanil has improved the recovery profile of patient. However, propofol does have dose dependent cardiovascular depression. Newer inhalational anesthetic agents like sevoflurane and desflurane with cardiovascular stability can also be used for induction and maintenance of anesthesia. Rapid recovery from newer inhalational agents may lead to emergence delirium due to delayed action of analgesics or regional techniques for postoperative pain relief.
Endotracheal intubation: The goal is to secure the airway with endotracheal tube without producing any regurgitation and vomiting.
The intubation procedure involves three objectives:
  1. To prevent hypoxia during the induction intubation sequence.
  2. To minimize the time between induction and tracheal intubation (Airway is unprotected by the patient's reflexes).
  3. To apply measures to prevent pulmonary aspiration of gastric contents.
The first of these objectives is normally met by preoxygenation of patient for at least 3 minutes.
The second objective involves minimization of the induction-intubation interva which can be achieved by hypnotic agent followed by administration of rapidly acting neuromuscular blocking agent. Duration of laryngoscopy and intubation should be minimal.
Thirdly the chance of aspiration is diminished with rapid sequence intubation (RSI by applying cricoid pressure, refraining from positive pressure ventilation after neuromuscular blocking agents and before tracheal intubation is accomplished. Laryngoscopy and intubation should be attempted only when neuromuscular blockade is adequate.
One must be ready with airway rescue plan in case intubation is not successful with three repeated attempts by experienced anesthesiologist.
Muscle relaxants are used to facilitate the intubation during rapid sequence intubatio. Suxamethonium is the only drug which has rapid onset of action within 60 seconds. However, it does not come without its side effect like bradycardia, hyperkalemia, increased intracranial pressure (ICP) and in some sensitive cases it may precipitate malignant hyperthermia.
There is no substitute for the short duration of action of succinylcholine for aggressive airway management in the case of an unexpectedly difficult intubation in order to prevent life-threatening hypoxia.
Recently the intermediate acting nondepolarizing neuromuscular blocking drug like rocuronium in dose of 1 mg/kg and has been used for rapid intubation and it can be accomplished within 60 to 90 seconds.26 with the introduction of sugamadex, new neuromuscular reversal agent the muscle relaxation can be reserved within 3 minutes. Thus can be helpful and life-savings in a situation, when patient cannot be ventilated and intubated after the administration of rocuronium
The priming principle of relaxatio can also be used by giving 1/10th of the total dose 3 minutes prior to the 14loading dose of muscle relaxant. This allows rapid onset of action of nondepolarizing muscle relaxant and one need not have to wait for 3 minutes for intubation. Earliest one can easily intubate the patient is 90 seconds.
Maintenance of anesthesia: Anesthesia can be maintained by either inhalational technique or total intravenous anesthesia with propofol. Narcotic sedation with fentanyl and sufentanil can be administered with caution. Intermediate acting neuromuscular blocking drugs are good choice for achieving muscle relaxation, e.g. vecuronium, atracurium, and rocuronium.
 
Reversal of Neuromuscular Blockade
At the end of surgery patients can be reversed with neostigmine. If patient condition demands postoperative ventilator support the patient need not be reversed and patient can be put on ventilator to provide controlled/assisted ventilation with or without PEEP.
 
Extubation
All patients who are extubated at the end of surgical procedure should be closely monitored till complete recovery. Take precautions to avoid aspiration at the end of anesthesia also. Patient who had difficulty in intubation, the extubation should be delayed till the patient is fully awake or extubation can be performed over the tube exchanger. In case of difficulty in ventilation or maintenance of airway following extubation, tube exchanger can be used for rapid and successful re-intubation.
 
Anesthesia Outside the Operation Room
For administration of anesthesia, all available induction agents can be used. Etomidate is a hemodynamically stable induction agent, however, the influence of possible etomidate-induced adrenocortical suppression must be considered. Total intravenous anesthesia can be used for maintenance of anesthesia. General anesthesia with endotracheal intubation and controlled ventilation can be given with usual monitoring. Rapid sequence intubation is considered the safest mode; however, awake intubation can also be performed in selected cases. Hypothermia should be taken care of in CT-Scan, MRI and cardiac catheterization department.27 Patient under monitored anesthesia care should receive oxygen supplementation throughout the procedure.
 
Advantages of Local/Regional anesthesia/analgesia
  • Decreased blood loss
  • Improved perioperative graft patency in vascular reconstruction
  • Reduced incidence of venous thrombosis
  • Combined regional and general techniques may improve outcomes in selected cases
  • Can be used in significant cardiovascular disease, severe pulmonary disease and major abdominal or thoracic surgery
  • Pre-emptive analgesia with epidural anesthesia enhances perioperative comfort of the patient
  • Drug interaction with chronic medications can be minimized (antihypertensive, antiarrhythmics, and narcotics, sedatives and insulin) by avoiding general anesthesia.
Local anesthesia is always the safest technique whenever the patient's are with stomach.
 
The Limitations of Local Anesthetics
  • Limited amount of local anesthetic agent safe to inject.
  • The inability to inject through infected tissue.
  • The difficulty of its use on children and anxious patients
  • Supplement local anesthesia required with intravenous anxiolytic agents whenever necessary.
  • Allergy to local anesthetic agents.
The most commonly used local anesthetic agent is 2 percent plain lidocaine with or without addition of epinephrine. More concentrated solutions are needed for nerve blocks while solutions as dilute as 0.25 percent are effective for infiltration anesthesia. While injecting local anesthetic agent, use the finest possible needle available which will not break. Inject while pushing the needle forward (as well as when withdrawing the needle) and if needed, bend the long needle such that it remains parallel to the skin during injection thereby allowing injection in the correct plane. Ideally, a patient should feel only a single needle prick per wheal. Whenever possible, subsequent injections should be performed through skin that has already been anesthetized.
 
Field Blocks/Peripheral Nerve Plexus Block
Peripheral nerve block or field block is an alternative to simple infiltration anesthesia. This is most useful for blocking sensation of a large patch of skin, where as local infiltration would require multiple smaller injections, e.g. surgeries on extremities.
Performing the peripheral nerve block/plexus block under ultrasonic guidance (USG) improves the success and quality of block. The USG is very helpful in patient who cannot be given proper position to perform the plexus block in view of severe pain, burns contractures, rheumatoid arthritis, etc.15
 
Central Regional Blocks
Spinal, epidural or combined spinal epidural anesthesia/ analgesia can be given.
One must ensure before institution of central regional block that the patient is either hemodynamically stable or stabilized.
If patient is in severe respiratory compromise, severe abdominal distension, strangulated hernia or uncomfortable in supine position, it is advisable to give general anesthesia and control the ventilation, in order to maintain the oxygenation.
If patient coagulation status is in doubt or patient is on antiplatelet or anticoagulant therapy, it is better to proceed with general anesthesia.
 
Ketamine for Analgesia
In areas where morphine is expensive or not widely available, patients suffering with severe pain, as from cancer or multiply fracture ribs, can receive ketamine by low dose infusion. To infuse ketamine for analgesia, first give a small bolus (0.25 mg/kg) of ketamine intravenously and dose should be titrated upward carefully to eliminate pain but not produce dissociation, followed by 0.5 mg/ml ketamine in saline to be given at a rate of 0.5 to 1 mg/kg/hr.
 
Postoperative Care
Postoperative anesthetic issues are to be managed promptly in order to reduce the morbidity and mortality. Some of them are as follows:
  • Oxygenation: oxygenation and airway stability has to be monitored clinically as well as with pulse oximeter. All patients should be given oxygen supplementation until they are fully awake and stabilized.
  • Need for reintubation: some patients may need reintubation following the extubation. This may be either immediate or within few hours postoperatively. Patient's need to be monitored for adequacy of breathing very closely and emergency intubation tray must be kept ready next to patient in order to prevent hypoxia and its consequences.
  • Inadequate neuromuscular block reversal: one must monitor the neuromuscular blockade following reversal of non-depolarizing muscle relaxants. The peripheral nerve stimulator helps in guiding the reversal of neuromuscular blockade and should be used whenever available. The inadequate reversal is observed during emergency cases since these patient may have acidosis, presence of electrolyte abnormalities especially hypokalemia and inadvertent hypothermia associated with infusion of large amount of intravenous fluid, blood and blood products within short period of time.
  • Mechanical ventilation: There are innumerable causes for a patient to be mechanical ventilated. Few of the major reasons are inability to maintain oxygenation with spontaneous breathing, increased work of breathing, supramajor surgery, COPD patient and hypothermic patient. The mode of ventilation is decided on individual case basis.
  • Pain: pain is the major cause of agitation, hypertension, tachycardia, increased oxygen demand and hypoventilation due to diaphragmatic splinting in upper abdominal surgery. The postoperative pain relief should be planned preoperatively whenever possible. This can be provided either with parenteral acetaminophen, NSAIDS and narcotics like morphine, fentanyl or sufentanil. The drugs can be given intravenously either with intermittent doses, through infusion with or without patient controlled analgesia. Local infiltration at incisional site, peripheral nerve block, regional analgesia can be good option unless they are contraindicated.
  • Nausea, vomiting and aspiration: there is high incidence of postoperative nausea, vomiting in patients who have received general anesthesia as compared to the one who received local or regional anesthesia. The incidence of nausea and vomiting can be reduced by giving optimum fluids, antacids (e.g. ranitidine, penteprozole), and prokinetic (e.g. metoclopramide, domperidone) and 5HT blockers (e.g. ondensetron, granisetron). The patient whose stomach was not empty preoperatively may be at risk of aspiration postoperatively as well, hence acid aspiration prophylaxis should be repeated postoperatively in those patients.
  • Temperature regulation: patient should be actively warmed using patient warming devices in case of hypothermia. Neonates, children and geriatric patients need special care as their temperature regulation mechanism is compromised. Hypothermic patient is at risk of hypoventilation, metabolic acidosis and increased bleeding.
  • Hypertension/hypotension: patient can have hypertension because of postoperative pain or pre-existing hypertensive patient. This should be treated promptly in order to prevent cardiac arrhythmias, myocardial ischemia, etc. there is a likely chance of postoperative bleeding due to sudden rise in blood pressure and inadvertent slippage of ligature of vessel. There can be postoperative hypotension due to residual effect of anesthetic agents, regional 16block inadequate preload, myocardial infarction, concealed bleeding, etc. Therefore, a patient's blood pressure should be monitored at least every 15 minutes. In high-risk and hemodynamically unstable patient it is better to measure blood pressure invasively to monitor beat to beat variability in blood pressure.
  • Cardiac arrhythmias: patient's rhythm should be monitored with cardioscope and arrhythmias should be treated promptly.
  • Acute metabolic disturbances, electrolyte derangements and fluid imbalance (dehydration or overhydration) are likely. If there is ongoing loss of fluid and blood from drains, nasogastric tubes and urine output. These need to be detected in time and treated promptly.
  • The estimation of electrolytes should be done at least 4 to 6 hourly.
  • The fluid should be administered with the monitoring of central venous pressure and urine output.
  • Acute renal failure is observed many times in emergency cases with trauma patient, septicemic patient, preoperatively dehydrated or in patients with long standing hypotension. One should try to prevent perioperative renal failure by using renal protective strategy. This involves maintaining intraoperative blood pressure, fluid and electrolyte or renal replacement therapy. Low dose dopamine does not protect renal function but fenoldopam has been shown to protect it.
  • Postoperative cognotive dysfunction (POCD): Postoperative delirium and confusion is commonly observed in geriatric patient and its incidence is more whenever atropine has been used intraoperatively. The delirium and confusion normally last from few hours to 24 hours. One should keep in mind that it can be due to cerebrovascular causes and may need to be thoroughly evaluated.
  • Deep vein thrombosis (DVT): DVT prophylaxis should be given whenever heparin or low molecular weight heparin (LMWH) is not contraindicated because of ongoing bleeding issues. The high-risk patients for developing DVT are obese patient, geriatric patient, obstetric patient, chronic immobilation and lower limb trauma, etc. The patient can be given calf muscle exercises by sequential compression and decompression device, foot pump and physiotherapy.
  • Use of aseptic precaution and barrier nursing will prevent infection.
  • Anesthesiologist need to decide how long a patient can remain in postanesthesia care unit or will need to be cared in specialized intensive care units.
Regardless of choice and method of anesthesia management, one must adhere to certain general principles. These include maintenance of patent airway, adequate ventilation with proper oxygenation and normal carbon dioxide concentration with hemodynamic stability. The morbidity and mortality can be significantly reduced if expert personnel are available to manage unanticipated difficult intubation and for the crisis management.
Therefore, assess the risk and stress of the proposed surgery and it's relative to its benefit, in view of the physiological reserve of the patient. Thereby adjust the technique of anesthesia and choice of drugs accordingly for the optinal outcome.
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