Does paramedic intubation improve patient outcome?

Since the position statement on pre-hospital airway management by the Joint Royal Colleges Ambulance Liaison Committee in 2008, the debate has shown no sign of relenting. The prevailing argument for those who are pro-paramedic endotracheal intubation has long been that the original position statement was based on low quality international research which is not entirely transferable to UK practice. With this in mind, there have been increased efforts in recent years to produce data which can provide an accurate and reliable answer to the question of whether paramedic intubation is beneficial to patient care.

This meta-analysis investigated the outcomes of adult patients who had suffered a non traumatic out-of-hospital cardiac arrest and as part of their treatment had either an endotracheal tube inserted or a supraglottic airway device placed by a paramedic.

The primary search identified 3 454 papers and ultimately 10 observational studies met the inclusion criteria for this meta-analysis representing 34 533 individuals who received endotracheal intubation (ETI) and 41 116 who received a supraglottic airway device. All presenting cardiac arrest rhythms were included.

Those excluded were paediatric patients, patients who had suffered a traumatic cardiac arrest, patients whose airway was managed by a nurse or physician, and any use of rapid sequence induction/intubation, or use of video or fibre-optic technology to assist with airway management.

The investigators were studying four outcome measures: i) incidence of return of spontaneous circulation (ROSC), ii) admission to hospital or survival for 24 hours, iii) survival to discharge or 30 days post discharge, iv) neurologically intact survival at discharge or 30 days post discharge.

Patients who received ETI had significantly higher ROSC (OR 1.28, 95% CI 1.05–1.55), survival to admission (OR 1.34, 95% CI 1.03–1.75) and neurologically intact survival to discharge (OR 1.33, 95% CI 1.09–1.61). No significant difference in overall survival to discharge was found, but arguably of equal importance was the improvement in neurological outcome in those patients who did survive to discharge.

Baseline demographics of the samples were similar between all studies; however, when baseline demographics were compared to the raw outcome data between studies there was large variation. All of the studies included originated from either Japan, Korea or the United States and Canada; given that the baseline demographics were similar between all studies, this discrepancy could be suggestive of a potential difference in pre-hospital care systems between those studies carried out in Asia and those carried out in North America.

The included studies were assessed for the quality of evidence in accordance with the GRADE (Grading of Recommendations Assessment, Development and Evaluation) system. All studies were identified as cohort studies and due to various factors all 10 studies were ranked as ‘low’ or ‘very low’ quality according to GRADE criteria. This was predominantly due to either a lack of statistical adjustment for known confounding variables (five studies) or because the sample sizes were small (two studies).

To attempt to mitigate for the poor quality of some of the data, the authors constructed sensitivity analysis models removing the studies ranked as ‘very low’ quality which reduced the number of studies available to only three or four per outcome. This re-analysis demonstrated no statistical significant difference in ROSC, survival to admission or survival to discharge. However, neurologically intact survival to discharge remained statistically significant in those patients who received endotracheal intubation (OR 1.33, CI 1.04–1.69).

While this study does indeed appear to demonstrate improved outcomes for cardiac arrest patients who receive paramedic endotracheal intubation, caution still needs to be exercised when considering these findings.

As a point of interest, it would seem to be somewhat inconsistent that, as a profession, paramedics criticise the decision to remove a procedure from their scope of practice as this decision appears to have been influenced by poor quality international evidence. However, at the same time, they suggest that paramedics should be carrying out this procedure but this recommendation also appears to be largely based upon poor quality international evidence.

In conclusion, while meta-analyses do provide substantial weight to an argument, the authors maintain that in order to answer the question once and for all, a good quality randomised controlled trial is essential.