Post-engagement Hearing Loss and Factors Affecting the Use of Diagnostics
Monday, August 25th, 2008One of the challenges associated with tactical medicine is the lack of diagnostic equipment at the point of injury and throughout the evacuation process. The tactical situation can limit the ability to use exam lights (of any color) and post-engagement hearing loss or environmental noise can eliminate your ability to use a stethoscope or to hear at all.
It is important to practice different techniques for assessing your casualties’ status that do not require the use of diagnostic tools or one specific sense. Hearing is the most regularly affected sense in the combat environment and it is the sense medics rely on the most heavily. Large blasts or firing a weapon can cause a significant ringing or a muffle in your ears. Therefore, when listening for slight variations in breath sounds or a fading pulse, it can be next to impossible to hear. That is why you must learn alternate methods for assessing your casualties’ status.
One skill that is often affected is measuring blood pressure. If you don’t know how to take a palp. blood pressure or know how pulse presence roughly correlates to levels of BP, you need to learn and practice the techniques. They also come in handy when working in the back of a helicopter or loud vehicle such as a track-vehicle or Stryker that are on the move. Here are some examples of pulse pressures associated with the presence of a pulse in various locations.
Pulse Location/Correlating Pulse pressure
Dorsalis-pedis pulse/90
Tibialis-posterior pulse/90
Radial pulse/80
Femoral pulse/70
Carotid pulse/60
These are very rough estimates and should only be used when no other means of measuring pressure are available. Studies have shown that this method often causes medical personnel to overestimate their patients’ pressure. We suggest this method be used to note which pulses are palpable during the initial set of vitals. Mark the location of these pulses with a Sharpie® when they are found. If a pulse that was present becomes weaker or disappears as time elapses, your casualty may be deteriorating, and you need to do something to address the cause of that deterioration. As stated earlier, this method should not be used if an accurate pressure is required.
The inability to use the sense most suited for the evaluation of a casualty is not just limited to taking blood pressure. It affects your ability to assess a needle decompression in a helicopter, looking for unilateral rise and fall of the chest, feeling for injuries and many other portions of your assessment. Regular practice of alternate methods of assessment should be included in your training regimen, because it’s too late to practice after your ears are ringing from the IED blast.
