Lights flash. A siren wails as an ambulance races to help a person whose heart has stopped beating.
In most cases, a 911 dispatcher sends an advanced life support, or ALS, ambulance to the scene, equipped with sophisticated gear and staffed with a crew of trained paramedics who can provide specialized care, including intubations and intravenous interventions.
Unfortunately, according to a study by health policy researchers at HMS and Harvard University, those advanced techniques also increase a patient’s risk of death.
People who experience out-of-hospital cardiac arrest and receive ALS en route to the hospital are more likely to die and to have poor neurological outcomes than those treated using basic life support (BLS) techniques, the study finds. The results appear in the December 2014 issue of JAMA Internal Medicine.
BLS ambulance crews provide a more limited set of treatments in the field. They provide air to a patient, for example, by using a simple hand-pumped ventilation bag rather than by intubating. BLS crews focus on rapid transport of patients to the nearest emergency department, while ALS providers are trained and directed to provide advanced life support care for cardiac arrest or its accompanying conditions.
“We know that community training, rapid and appropriate delivery of pre-hospital care, and high-quality hospital cardiac care may substantially improve survival rates,” says study co-author Alan Zaslavsky, an HMS professor of health care policy. “This study informs the choice between providing more care in the field and bringing patients as quickly as possible to hospital treatment.”
For the past several decades, ALS has been the dominant form of care for cardiac arrest and other medical emergencies in the nation, but there is little evidence that it saves lives compared with BLS services. The researchers found that cardiac-arrest patients who received out-of-hospital BLS instead of ALS were more likely to have survived to discharge and were also more likely to have survived 30 to 90 days after discharge. In fact, patients treated with basic life support were nearly 50 percent more likely to have survived than patients who received advanced life support. Hospitalized patients who received basic life support also had better neurological functioning, with fewer incidents of coma, vegetative state, or brain death than patients who had received advanced life support.
For this study, the researchers obtained data from a randomized sample of Medicare claims made by patients in nonrural counties who had used ambulance services for out-of-hospital cardiac arrest between 2009 and 2011. They then compared survival and other outcomes between patients who had received ALS and those who had received BLS. The scientists adjusted for possible sources of bias by studying comparable populations.