Prolonged CPR: Why It Sometimes Works

On August 5, 2013, a 37-year-old diesel mechanic from Ohio suffered cardiac arrest and was rushed to the hospital. The emergency team gave him CPR for 45 minutes, as well as medications and other medical interventions. At the end of that period, he was pronounced dead.

That wasn’t the full story, however. Five to seven minutes after he was declared dead—with no pulse or blood pressure—a trace of heart activity was detected on the EKG monitor. The emergency team went back into action—and the man made a full recovery.

Nobody really knows why prolonged CPR sometimes works. But studies are increasingly showing that it does. A recent study on longer CPR attempts, conducted in hundreds of hospitals, demonstrates that the patient’s chances of surviving rise if medical teams continue CPR just nine minutes longer than the average time. In the study, the average length of time CPR is continued varied dramatically between hospitals, between 16 minutes in hospitals with the shortest average to 25 minutes at those with the longest. This study demonstrated that patients receiving CPR at the hospitals with longer averages were 12% more likely to survive.

There is no set time guideline for how long CPR should be performed. The length of time is often determined by the patient’s problem and the condition he or she arrives at the hospital in. Usually, it is the doctor’s decision to “call it,” or decide when CPR stops. This decision is usually made based on how long CPR has been administered, the patient’s response, and what other methods have been tried.

The established orthodoxy is that prolonged CPR is generally a lost cause—and for patients who do survive, permanent brain damage is a common outcome. However, in this study, patients who recovered after prolonged CPR were no more likely to have neurological damage than those who recovered faster.

Even though the medical reasons behind this study’s results are still a mystery, there are a few possibilities. The study demonstrated that patients were more likely to recover after prolonged CPR if they didn’t respond to defibrillation. The study suggests a longer period of CPR gives doctors needed time to assess the patient’s condition and try different tactics, which, in some cases, could mean the difference between life and death.

In addition, it’s possible that during shorter durations of CPR, air gets trapped in the lungs, stopping blood flow to the heart. During more prolonged CPR, it’s possible the air would have a chance to work its way out of the lungs and allow blood to circulate more freely.

In addition, if the body has cooled a substantial amount, it is possible for the body to stay alive for longer periods without blood flow. It is also possible that, in cases such as that of the man in Ohio, where the body experienced recovery quite a few minutes after rescue efforts had stopped, it had cooled enough to survive without significant blood flow.

At this point, however, all of these possible reasons are conjecture. Further studies are needed to determine why prolonged CPR appears to add to a patient’s chances of survival, and why the patients who recover after prolonged CPR appear not to be more likely to suffer brain damage than those who undergo CPR for shorter durations.

It is clear, however, that hospitals that fall on the low end of the spectrum for length of time CPR is delivered should take a look at their practice—and possibly determine ways they can raise their averages. The results are fairly clear that prolonging CPR is not as futile as was once believed—and may even be life-saving for many patients.