Study highlights CPR’s rapid decline in success rates after 40 minutes

By Isobel Williams via SWNS

The chances of using CPR to survive plummet to less than one percent after 40 minutes, according to a new study.

Researchers found that a person’s chance of surviving while receiving cardiopulmonary resuscitation (CPR) for cardiac arrest in hospital declines rapidly from 22 percent after one minute to less than one percent after 39 minutes.

Similarly, the likelihood of leaving hospital with no major brain damage declines from 15 percent after one minute of CPR to less than one percent after 32 minutes with no heartbeat.

The University of Pittsburgh researchers believe their findings provide insights that may help guide hospital teams, patients and their families in deciding how long to continue resuscitation.

To get their results, published in the BMJ, the team measured the effect of CPR duration on outcomes for 348,996 US adults who had an in-hospital cardiac arrest between 2000 and 2021.

CPR was defined as the interval between the start of chest compression and the first return of spontaneous circulation or termination of resuscitation.

The main measures of interest were survival to hospital discharge and favorable functional outcome at hospital discharge, defined as a brain performance score of one (good cerebral performance) or two (moderate cerebral disability) on a 5-point scale.

They found that 67 percent of participants achieved return of spontaneous circulation with an average CPR duration of seven minutes, whereas 33 percent did not achieve return of spontaneous circulation with an average CPR duration of 20 minutes.

At one minute’s CPR duration, the probabilities of survival and favorable functional outcome among patients were 22 percent and 15 percent, respectively.

But as duration of CPR increased, the probabilities of survival and favorable functional outcome decreased to less than one percent for survival at 39 minutes and less than one per cent for favorable functional outcome at 32 minutes.

Assistant professor Masashi Okubo from the University of Pittsburgh School of Medicine said: “This was a well-designed study using the largest in-hospital cardiac arrest dataset in the world, making the findings pertinent for hospitals intending to improve their resuscitation performance.

“The findings provide resuscitation teams, patients, and their surrogates with insights into the likelihood of favorable outcomes if patients pending the first return of spontaneous circulation continue to receive further cardiopulmonary resuscitation.”