INTRODUCTION OF CRITICAL CARE ULTRASOUND
The word ultrasound has been in use for some time now.
In the late 1700's echolocation in bats was studied. After nearly a century thence, Curie brothers discovered the phenomenon of piezoelectricity, the princilple of which is still utilised for the ultrasound probes.
Interestingly, the Titanic tragedy too has a bearing on ultrasound, as it was after this tragedy that Langevin invented a hydrophone (possibly the first known transducer) to find articles at the bottom of the sea!! The early 1900's saw use in the field of sports (to ease pains in footballers! detecting brain tumors, detect gall stones, detect breast tumors). Since the discovery of ultrasound and its potential uses, as had been studied in bats, we have indeed come a long way.
The initial units were quite bulky and indeed very discomforting for the subject, the uses being only in a select few, which since then have changed.
Previously considered the realm of only highly-specialized radiology experts, now has made way to experts from a wide variety and backgrounds making full use of this new technology (emergency, surgeons, orthopedicians, gynecologists, neurologists and intervention specialists).
POCUS or point of care ultrasound is the new term coined for ultrasound done at the direct point of care i.e., at the bedside of the patient. This “bedside” would include critical units, emergency departments, operation theaters, outpatient units as well as situations on the field like trauma victims, roadside accident victims, war situations and also severely austere situations like mountains, snow, sports field, etc. The widespread outreach has been so extensive that we now even have POCUS been done in space stations!!!!
As you may guess the outreach is tremendous and the potential is great!
Just consider a situation of a medical emergency in a very remote area of our country, let us say a trauma situation in shock, and we require to take a decision about operating room or shifting to a higher center.
A quick-fast examination by ultrasound, either interpreted on the spot or by telemedicine by experts sometimes sitting miles away or indeed continents away, can help in making crucial decisions and hence save the life!!
The beginning of POCUS was indeed, as many would say, during the Vietnam war. It was used to good effect to save war victims.
During the early 80's pioneering work was done in this field by Prof. Daniel Lichtenstein.
He explored the lungs considered the graveyard for the sonologist and indeed also by prominent authors like Harrison (medicine), he covered the whole body and changed the scene forever. It is not without reason, he is known widely by many as the father of modern day POCUS. Later prominent bodies like WINFOCUS (World Interactive Network Focused On Critical Ultrasound) have helped to disseminate this knowledge to many countries and indeed to the resource poor areas as well (Brazil project).
The earlier uses of POCUS were in vascular access and conventional abdominal ultrasound as also with diagnosing gynecological emergencies. We have come a long way since then.
We now can approach the patient in a complete head to toes manner in an emergency situation.
A wide-range of structures can be evaluated by the use of ultrasound. Brain-brain substance, midline shifts, fractures, pupils, transcranial Doppler for monitoring patients of subarachnoid hemorrhage (SAH), and also helping to diagnose severely-injured brains and aid in brain death diagnosis. Sinuses, orbits, cervical spine area, neck, airways, esophagus, lungs, abdomen, including liver, kidneys, bowels, spleen, pancreas all are well visualized. The heart is seen in a totally different perspective by the point-of-care cardiac ultrasound, many decisions like fluid management, lines, pacing can be done. A good visualization of aorta, veins of the central circulation, and peripheral ones, too make the use more interesting.
In addition to this, a whole variety of procedures are now done bedside under direct ultrasound guidance, making all these procedures much more safe and accurate. Procedures like vascular access (both veins and arteries), nerve blocks, fluid tapping, drain insertions, transvenous pacing, drug injections and lumbar punctures can indeed be done with improved safety.
Unfortunately, in countries like India, strict acts governing ultrasound use are in place, which sometimes limit or restrict the use.
Acts like PCPNDT (Pre-Conception and Pre-Natal Diagnostic Techniques Act, 1994) which have been put in place to prevent female feticide has important benefits preventing the abuse of the ultrasound machine and indeed protecting the unborn child, but this also prevents liberal and free use of the machine and technology by wider sections of the emergency personnel, including paramedical or nonmedical staff.
We must have a good knowledge of these acts, its provisions and also its translations in clinical practice to be able to benefit our patients with most accuracy. Local authorities and hospital administrators must be taken into confidence, every time a new machine is procured or new users are added to the existing machine, and appropriate protocols prescribed by the authorities have to be followed stringently to avoid any medicolegal problems (including sealing of machines and legal action including jail). The authorities also require regular updating of the clinical activities by filling certain forms which must be done with due diligence and care as many a time even clerical errors are looked upon very strictly.
There are however many new applications which are being discovered regularly (transcranial Doppler, new procedures, lung classifications) which make this new field a very promising and fascinating one! Portability of these machines (much less bulky and smaller) now makes them easily transportable, to even remote locations and situations, and thus prove as invaluable tools to save lives.
Truly the modern day stethoscope is indeed the ultrasound probe!!!