July 1, 2009 | Shelley Wood
Seattle, WA - Despite efforts to save more people suffering from in-hospital cardiac arrest, rates of survival after in-hospital CPR are no better today than they were more than a decade ago, new research suggests. The analysis, looking at records for over 433 000 patients who received CPR between 1992 and 2005, showed that the rate of survival to hospital discharge hovered at around 18% over the entire study period.
Survival rates were worse among male, nonwhite, and older patients, the researchers, led by Dr William J Ehlenbach (University of Washington, Seattle), note.
“During the time period we studied, the acute cardiac life support guidelines were updated at least two times, so both on a national level, in terms of guidelines, and within hospitals, there’s been an ongoing attempt at process improvement,” Ehlenbach told heartwire. “We thought that there might be some slight improvement over that time period, but one question we had going in was whether or not, at least theoretically, you can reach a point where the systems for delivery of in-hospital CPR can no longer be dramatically improved.”
According to Ehlenbach, it’s not totally clear whether that point has been reached, although he thinks the study findings likely reflect the fact that while CPR has probably improved, the types of patients receiving resuscitation attempts are probably sicker and less likely to be ideal candidates for CPR. “This highlights the need for improved communication between doctors and patients, particularly older patients with chronic diseases,” he said.
CPR survival rates hold steady
Researchers used fee-for-service Medicare data to identify patients age 65 years or older who had received CPR in US hospitals. They found that while the number of patients receiving CPR over the study period increased (433 985 in all), survival rates remained relatively static. CPR was more common among black patients and other nonwhite patients than among white patients, yet survival rates in the nonwhite groups were lower.
According to the authors, “some but not all” of the differences in survival between different racial groups may be explained by the hospitals where different groups receive treatment. “Black patients more often receive care at hospitals where patients of all races have lower odds of survival after CPR,” they write.
To heartwire, Ehlenbach also noted that certain diseases—hypertension and kidney disease, for example—are more common in African Americans, and response to CPR may depend in part on the kinds of underlying chronic diseases. “Another issue that we think would be interesting to know more about is whether preferences for care at end of life are different by race and whether that is playing a role here.”
Another important finding, according to the authors, was that the proportion of patients dying in the hospital after previously being resuscitated by CPR has also increased over the study period. “That was surprising to us, because over this time period there certainly was an increasing emphasis on patient education on end-of-life care and seemingly more widespread consideration of do-not-resuscitate orders,” Ehlenbach commented. The numbers may hint at the fact that patients who really are not appropriate candidates for resuscitation are still undergoing CPR efforts. “Ideally, every patient with serious chronic disease is having a conversation with their doctors about CPR and really getting to the [understanding] that there are situations in which CPR is likely to be effective and situations in which it’s much less likely to be effective.”
The authors also speculate that another reason for the lack of improvement in in-hospital survival post-CPR may be that many of the changes in CPR performance have been targeted at out-of-hospital CPR, not in-hospital. CPR by bystanders, improved emergency-response tactics, and the proliferation of automated external defibrillators are factors that “do not have analogs” in the in-hospital setting, they note.
An even bigger reason, however, is likely that older Americans are now living with multiple serious chronic diseases, such that acute illnesses that trigger cardiac arrest occur on the background of major comorbidities. “It’s possible that we are delivering better CPR, but we’re delivering it to sicker patients or patients who are less likely to survive,” Ehlenbach concluded.
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