Your attention please, Code Blue, Jackson 625! Doctor Heart, 3 South! Code 99, Radiology! Such announcements have been echoing through hospital public address systems for 40 years, galvanizing emergency resuscitative efforts by nurses and physicians to save "hearts that are too good to die." The modern era of cardiopulmonary resuscitation (CPR) began in the late 1950s, when Kouwenhoven and colleagues, researchers at Johns Hopkins Medical Center, discovered that closed-chest cardiac massage restores cardiac contractions. "The use of this technique on 20 patients has given an overall permanent survival rate of 70%. Anyone, anywhere, can now initiate cardiac resuscitative procedures. All that is needed are two hands," they proclaimed.1 This high success rate was possible because most of the patients arrested while in the operating or recovery room.
The original purpose of CPR was to resuscitate patients who had sudden cardiac arrest but were otherwise in good physiologic condition.2 As techniques improved and were adopted worldwide, CPR became an integral part of health care. Today it's one of the most frequently performed interventions in the world.3 Approximately 30% to 40% of hospitalized patients who are dying undergo CPR.4 This high frequency of use has been criticized by those who view CPR as a "violent, damaging, painful, alarming, and undignified intervention that can be justified only by sufficient benefit to the patient."5
Numerous studies of survival rates after in-hospital CPR have been conducted in the past three decades. However, differences in definitions, eligibility criteria, patient populations, and quality of resuscitative efforts make it difficult to assess the true effectiveness of in-hospital resuscitation. Prospective, randomized, controlled studies are difficult, if not impossible, to conduct in resuscitation research. Hence, the Utstein Task Force and the National Registry of Cardio-Pulmonary Resuscitation have established guidelines for collecting CPR data.3, 6
FACTORS THAT AFFECT IN-HOSPITAL CPR
Despite flaws, some studies do provide insight into survival rates and the factors that influence them. Three major reviews of 253 publications documenting 59,000 in-house resuscitation efforts between 1959 and 1992 show that the 15% worldwide average survival rate did not change significantly during this time period.4, 7, 8 In one of the most comprehensive and clearly written of these meta-analyses, Schneider and colleagues examined results pooled from 98 studies of 19,995 patients and identified factors that affect CPR survival, some of which are addressed below.8
Findings from 33 of the studies showed a relationship between age and CPR success. About 16% of patients under age 70 survived CPR compared with 12% of patients aged 70 and older. However, it's difficult to distinguish the effects of age from the effects of comorbidities.
In four studies, an average of 29% of patients survived CPR attempts that lasted less than 30 minutes, whereas only 1% survived attempts lasting longer. Findings from 35 reports showed that among patients who were resuscitated but died before discharge, 46% died within 24 hours, 73% within 72 hours, 86% within one week, and 98% within one month. Among those surviving to discharge, statistics from 20 reports showed that an average of 83% were still alive at six months, 73% at 12 months, and 55% at 24 months. Statistics pooled from 66 studies showed that only 2% of patients had neurologic impairment. Findings from 35 studies showed that 20% of patients with ventricular fibrillation or ventricular tachycardia survived CPR, whereas only 8% of patients with other arrhythmias survived.
Immediate availability of trained personnel and equipment increases the likelihood of success. Data from 98 studies showed a 31% rate of success among perioperative patients and a 15% rate among nonoperative patients. Results from 35 studies showed that among patients who had arrests in the cardiac catheterization laboratory, there was a 73% success rate; among those in the operating room, ED, and ICU, the success rate was 15% to 32%. Patients on the unit had lower success rates-about 11%.8
IMPROVING RESUSCITATION OUTCOMES
The overall CPR survival rate has remained the same over the past 30 years, despite improvements in training, equipment, and drugs. So the question remains: What can be done to improve outcomes?
Most cardiac arrests are attributed to ventricular fibrillation, which requires immediate defibrillation. The sooner the defibrillation, the greater the chance of recovery.9-11 Each minute that defibrillation is delayed, the chance of restoring a perfusing rhythm is reduced by about 7% to 10%.11 As Beck and colleagues noted in 1956, "the heart wants to beat and often it needs only a second chance."12 Automated external defibrillators (AEDs) have made it possible to shorten the time before the first defibrillation in non-critical care units, giving the heart that "second chance."
Researchers have recently shown that non-critical care staff can easily learn to operate AEDs.13 In fact, it's easier to train them to use AEDs than it is to teach them to perform basic CPR.9 By having AEDs available in non-critical care areas, survival rates should increase. Preliminary results of a study conducted at the Miriam Hospital in Providence, Rhode Island, showed that first-responder use of an AED in non-critical care areas, when compared with conventional defibrillation by the code team, improved the survival-to-discharge rate in both non-telemetry patients (60% versus 13%) and telemetry patients (60% versus 54%).14
Because of the success of AEDs, the American Heart Association's Guidelines 2000 for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care call for increased availability of AEDs, stressing that "the capability to provide early defibrillation within patient-care areas is an obligation of the modern hospital." They recommend defibrillation within three minutes in a hospitalized patient in cardiac arrest.15
"Do not attempt resuscitation" (DNAR) guidelines can also increase survival rates by helping to avoid futile and costly CPR. (The Utstein Task Force endorses the abbreviation "DNAR" rather than "DNR" because the latter implies that the patient would have been successfully resuscitated if CPR had been initiated.) When 405 outpatients were asked in a recent study to imagine themselves to have a poor prognosis and to be incompetent to make decisions, they decided against life-sustaining treatments about 70% of the time.16 At the end of life, it's natural to want to be surrounded by family members rather than the code team. This can occur only if early and candid discussions about CPR and DNAR take place and if decisions are communicated.
The goal of CPR is simple: The right patients need to be resuscitated and they need to be resuscitated right.2