By David Jaslow
In Parts VI through VIII of this series we covered the acquisition and interpretation of traditional vital signs in the rehab sector as part of our overall approach to implementation of a fireground medical screening exam. This month we will focus on what other diagnostic tests (which I have termed "non-traditional" vital signs) may or may not aid us in a rapid evaluation of emergency responders to determine if they are fit to return to active duty at the emergency scene.
The caveat concerning measurement of these non-traditional vital signs is that the goal is to ascertain whether an acute fireground medical emergency exists. We are not interested in discovering minor abnormalities that do not merit emergency treatment nor are we interested in providing extensive medical care in persons who should be in the treatment sector if they are patients. Therefore, it will be unlikely that these tests will need to be implemented during routine screening of firefighters or other emergency responders who appear well, have no complaints and have traditional vital signs that are normal or close to normal.
That being said, the most likely reason we would need to employ point-of-care testing to obtain these non-traditional vital signs is that a firefighter presents to the rehab sector in an exhausted state that would simulate a true medical emergency. Determining whether or not a fireground medical emergency exists depends on a rapid history, focused physical exam, acquisition of vital signs and application of technology (which is our point-of-care testing).
Relying on technology
Technology becomes very important in this particular scenario because all of the traditional vital signs will be grossly abnormal and will not aid us in determination of whether or not a true emergency exists. Pulse rate will be very fast, blood pressure will most likely be elevated, respiratory rate will be rapid and the firefighter may feel warm and moist due to diaphoresis.
Should we rush every 25-year-old off to the ambulance because he stayed inside the burning building for a few minutes longer than he should have and now slumps into the chair in rehab? Clearly not, but it can be quite challenging to differentiate those firefighters who truly need emergency medical treatment and transport from those who just need rest and rehydration. During the first five to ten minutes, both groups may appear identical in their initial presentation. Furthermore, as the firefighters age into their 40s and 50s, the chances that the presentation of a true medical emergency may be masquerading as exhaustion increase, as does the adrenaline surge among EMS personnel charged with properly interpreting this scenario.
There are several rapid diagnostic measurements that EMS personnel (primarily paramedics) could utilize to evaluate firefighters: pulse oximetry, blood glucose testing, end tidal CO2 analysis, SpCO (carbon monoxide) measurement and 12-lead ECG. Again, none of these tests are necessary during standard evaluation of firefighters who have been sitting in the rehab sector for 15-20 minutes without complaint and are ready to have their vitals taken in anticipation of a presumptive discharge.
We have previously mentioned how the fireground medical screening exam does not include any invasive testing. This includes blood glucose level testing. Firefighters who are diabetic will be known in their departments. Those rare emergency responders with diabetes who become hypoglycemic because they have not eaten should demonstrate altered mental status or other symptoms that clearly mandate removal to the treatment sector and conclude the medical screening exam. Those persons with diabetes who may have hyperglycemia will probably not develop symptoms until blood sugar levels are well above 400 mg/dl. Furthermore, neither new onset diabetes nor DKA develop over a few hours. Regardless of the etiology of high blood sugar, these persons should indicate that this may be the culprit and once they complain of acute illness, they become patients and are removed to the treatment sector.
Pulse oximetry can rapidly help EMS personnel ascertain whether or not an exhausted firefighter who may appear weak and diaphoretic is suffering from hypoxia. Otherwise, routine pulse oximetry as a screening tool is unnecessary unless it is being used to obtain a value for the pulse as a matter of convenience. It is quite likely that hypoxic firefighters would also complain of shortness of breath and/or have abnormalities in other vital signs that would immediately tip off the rehab sector officer that an acute medical emergency exists.
Measurement of end tidal CO2 can provide an estimation of acid-base abnormalities and respiratory insufficiency. However, its use is also unnecessary during routine rehab operations since firefighters with acute dyspnea to the degree that grossly abnormal EtCO2 values are produced will also have abnormal respiratory rates and complain of shortness of breath. EtCO2 will also have limited value in the setting of the acutely exhausted firefighter because the tachypnea that is present in an overworked state will result in low EtCO2 as lactic acid is blown off in the form of CO2 and water vapor. Thus, initial values will likely be in the 20s or low 30s, but will normalize quickly.
Measurement of SpCO, the percentage of carbon monoxide in the bloodstream, can only be accomplished with the Masimo RAD-57 at this point in time. Any firefighter who could have a fireground medical emergency and presents to rehab from operations should immediately have the RAD-57 applied and a reading taken. Low to moderate levels of CO poisoning could occur from a mask leak (or not wearing SCBA while performing overhaul) and these firefighters can appear to be simply physical exhausted when in fact that is not the case. Otherwise, there is no need to routinely measure CO levels in firefighters who appear well, have no complaints and are awaiting exit vital signs.
Finally, 12-lead ECG acquisition is absolutely necessary when confronted with a firefighter who may possibly be experiencing a fireground medical emergency. Acute myocardial infarction has taken the life of firefighters in their early 20s in this country and it is currently the most common cause of non-fire related death among firefighters. Any abnormality seen which could represent ischemia should prompt immediate transport to an ED. Otherwise, a quick 12-lead may help put to rest fears of a more serious situation in those firefighters who do actually have exhaustion rather than an unstable medical emergency. Once again, this procedure is unnecessary as a screening tool for the general rehab sector participant who has vitals within or close to the normal range and does not have physical complaints.
Next month, we will wrap up this discussion with an algorithm for what to do and when to do it when implementing the fireground medical screening exam.