Basic best in cardiac arrest

RESEARCH showing out-of-hospital cardiac arrest patients in the US treated with basic life support have better survival rates and neurological outcomes than patients treated with advanced life support has divided Australian experts.
    
An observational cohort study, published in JAMA Internal Medicine, considered survival to hospital discharge and to 90 days of 31 292 patients attended by an advanced life support (ALS) ambulance for out-of-hospital cardiac arrest, and 1643 attended by a basic life support (BLS) ambulance. (1)

The researchers found that survival to hospital discharge was greater in those receiving BLS (13.1% v 9.2% for ALS), as was survival to 90 days (8.0% v 5.4% for ALS). BLS was also associated with better neurological functioning among hospitalised patients.

They described BLS as including rapid transport and basic interventions such as effective chest compressions, bag valve mask ventilation and automated external defibrillation. ALS providers were described as paramedics trained to use sophisticated, invasive interventions to treat cardiac arrest, including endotracheal intubation, intravenous fluid and drug delivery, and semiautomatic defibrillation.

While the researchers noted several limitations — including the likelihood that ALS would be provided for higher-risk patients — they concluded that their results called into question the “widespread assumption” that ALS resulted in better patient outcomes than BLS.

Associate Professor Paul Middleton, clinical associate professor of emergency medicine at the University of Sydney, told MJA InSight the findings were “massively applicable” in Australia.

“They have shown such a marked difference in outcomes that I think it’s absolutely applicable here and it really does reinforce a lot of the prior research that has been done”, said Professor Middleton, who also heads the newly formed organisation Take Heart Australia, which aims to boost cardiac arrest survival by strategies including community engagement.

“What we are talking about here is basic life support, which [includes] very simple interventions centring on high-quality continuous chest compressions, started immediately and with minimal interruptions, as well as early defibrillation”, he said.

These interventions had been accepted for a long time as being the most important aspects of cardiac arrest treatment, and previous evidence suggested ALS interventions had no benefit, Professor Middleton said. (2)

However, Professor Vivienne Tippett, head of discipline for paramedicine at the Queensland University of Technology, said the study, while robust, should be interpreted with caution.

She told MJA InSight that in Australia the basic educational requirement for most paramedics was a bachelor’s degree, with intensive care paramedics requiring at least 2 years’ practice and postgraduate qualifications. In contrast, training requirements for US paramedics were variable and often delivered by college or vocational education programs that were much shorter than Australian programs.

“We might be comparing apples with oranges if we blindly absorb these sorts of studies from some overseas countries without paying careful attention as to whether or not the educational standards and the practice arrangements are the same”, Professor Tippett told MJA InSight.

However, Professor Middleton disagreed. “There is undoubtedly more education that goes into paramedic training on a higher level than there used to be, however, that doesn’t alter the fact that paramedics are trained to the same protocols”, he said, adding that he was not criticising paramedics.

“They do great work in 99% of the job they do. NSW ambulance receives 1.1 million triple zero calls per year and … there are probably about 5000 cardiac arrests a year. You can see this is [a small percentage] of a paramedic’s job [and] one I believe they don’t do well.”

Professor Middleton said this was not paramedics’ fault, as training in ALS interventions had been prioritised worldwide when consistent training in BLS would probably lead to better outcomes.

An accompanying commentary in JAMA Internal Medicine backed the call for further evaluation of ALS versus BLS, saying most ALS interventions “are ‘advanced’ chiefly in our expectations, not in evidence-based efficacy”. (3)

Professor Middleton agreed on the need to go “back to basics”, saying this was the aim of Take Heart Australia, which wants to increase recognition of cardiac arrest and promote cardiopulmonary resuscitation training in the community, and agitate for the widespread distribution of easily accessible defibrillators.

Professor Tippett said the major challenge with cardiac arrest was lifting the low survival rates.

“What we do know with some confidence is that early compression at the appropriate rate and depth is one of the strongest predictors of survival”, Professor Tippett said, noting that this was promoted in the Australian Resuscitation Guidelines.

1. JAMA Intern Med 2014; Online 24 November
2. N Engl J Med 2004; 351: 647-656
3. JAMA Intern Med 2014; Online 24 November

(Photo: Lisa S / Shutterstock)