Clinical death is the absence of respirations and pulse, which is the colloquial understanding of death. It can sometimes be reversed, if the cause of the cardiac arrest is something the patient can be treated for in the field (e.g., if the patient has an electrolyte deficit, we can administer drugs to correct it, at which point the patient’s heart may or may not respond to CPR and defibrillation. Sometimes it does, but more often it doesn’t).

Without intervention — bare minimum CPR, O2, defibrillation, administration of medications to treat certain types of nonperfusing rhythms — these people will experience biological death (cessation of brain activity) in minutes, because their heart isn’t pumping oxygenated blood to their brain and other organs. In the field, and even generally in the clinical setting, it is a distinction without a difference; simply put, if the patient’s heart just isn’t working, there often isn’t anything we can do to make it start working again, in which case we follow our protocol for determining death in the field, which is typically three rounds of ACLS CPR without any physiological response to our interventions. If that happens, we discontinue treatment and consider that patient dead. Literally we put a sheet over them, radio the ED and tell them that we’re determining death at such-and-such a time, tell the cops to start their death investigation (which is generally like “hey, this patient is 100 years old, do you have a funeral home you want to use?”), pack up our equipment, and head back to the station to have breakfast.

The debate this guy is having about clinical vs biological death is one that almost never comes into play, except in the ICU. If we bring a patient into the ED in cardiac arrest, and I tell the ED physician “I found this guy on his bathroom floor in vfib (a potentially reversible type of nonperfusing cardiac arrhythmia where the heart is just wiggling around in an unorganized way that doesn’t allow it to pump blood to the body) and I’ve been doing CPR for thirty minutes without any response”, the ED physician is going to say “okay let’s do three rounds of ACLS CPR” and then call it if there still isn’t any response, just like we would do in the field.

The only time that biological death comes into play when determining death is really in the ICU. Say EMS brings a patient to the ED with what we would call return of spontaneous circulation — their heart starts working after our treatments — but they are comatose because their brain had been without oxygen for too long before we got there. These patients get transferred to the ICU, where the ICU doctor makes the determination to continue treatment, based on whether or not she believes that the patient’s brain can recover from the anoxia, which is a somewhat rare outcome.