Wednesday, November 24, 2004

A is for Airway.....
From the Annals of Emergency Medicine via The New York Times:Trauma: For Medics, an Airway Quandary
Accident victims with brain injuries who were given breathing tubes by ambulance crews before they got to the hospital were four times as likely to die as a result of the accident as those given the tubes later, a new study finds. They were also more likely to suffer neurological problems.

The researchers, writing in this month's Annals of Emergency Medicine, based their findings on more than 4,000 patients who had been intubated in or out of the hospital.

While those who were given the tubes by ambulance crews appeared to have been more severely injured than those who were not - and as a result, more likely to die - the association between a higher mortality rate and out-of-hospital intubation remained even when this was factored out, the study said. Still, the researchers wrote, "We do not believe that the correct clinical interpretation is to defer out-of-hospital endotracheal intubation."

Instead, they said, future research should look at what may be going wrong when the practice is done in the field. One possible explanation is that paramedics are not allowed to administer the same drugs that doctors use when putting the tubes in.

The study also said that paramedics had less training with the tubes than doctors and that it was not uncommon for the tubes to be inserted wrong.

The study was led by Dr. Henry E. Wang and Dr. Donald M. Yealy of the University of Pittsburgh. The tubes are often given to people with brain injuries to keep their airways free and, the thinking goes, to reduce the risk of further brain injury caused by lack of oxygen.
The wonderful folks at Annals graciously provide free access to the article Out-of-hospital endotracheal intubation and outcome after traumatic brain injury here:
Study objective: Previous studies disagree about the effect of out-of-hospital endotracheal intubation on traumatic brain injury. This study compares the effects of out-of-hospital endotracheal intubation versus emergency department (ED) endotracheal intubation on mortality and neurologic and functional outcome after severe traumatic brain injury.

Methods: From the 2000 to 2002 Pennsylvania Trauma Outcome Study (a registry of all patients treated at trauma centers in the Commonwealth of Pennsylvania), adult patients with head/neck Abbreviated Injury Scale score of 3 or greater and undergoing out-of-hospital endotracheal intubation or ED endotracheal intubation were included. Transferred patients were excluded. The primary outcome was death (on hospital discharge). The secondary outcomes were neurologic (good versus poor, inferred from discharge to home versus long-term care facility) and functional outcome (determined from a Functional Impairment Score). The key exposure was endotracheal intubation (out-of-hospital endotracheal intubation versus ED endotracheal intubation). Using multivariate logistic regression, odds estimates for out-of-hospital endotracheal intubation were adjusted using age, sex, head/neck Abbreviated Injury Scale score, Injury Severity Score, mechanism of injury (penetrating versus blunt), admission systolic blood pressure, mode of transport (ground only versus helicopter or helicopter+ground), and the use of out-of-hospital neuromuscular blocking agents. A propensity score adjustment accounted for the potential effects of preexisting conditions, inhospital complications, and social factors (drug and alcohol use, race, and insurance coverage).

Results: There were 4,098 patients with head/neck Abbreviated Injury Scale score of 3 or greater who received either out-of-hospital endotracheal intubation (n=1,797, 43.9%) or ED endotracheal intubation (n=2,301, 56.1%). Adjusted odds of death were higher for out-of-hospital endotracheal intubation than ED endotracheal intubation (odds ratio [OR] 3.99; 95% confidence interval [CI] 3.21 to 4.93). Out-of-hospital endotracheal intubation was associated with an increased adjusted odds of poor neurologic outcome (OR 1.61; 95% CI 1.15 to 2.26), moderate or severe functional impairment (Functional Impairment Score 6 to 15; OR 1.92; 95% CI 1.40 to 2.64), and severe functional impairment (Functional Impairment Score 11 to 15; OR 1.80; 95% CI 1.29 to 2.52).

Conclusion: Out-of-hospital endotracheal intubation was associated with adverse outcomes after severe traumatic brain injury. The implications for current clinical care remain undefined
So the authors analyzed reports from the Pennsylvania trauma registry and found that patients that were intubated in the pre-hospital setting were four times as likely to die than patients with in-hospital intubation. While the out-of hospital intubated patients were sicker, the authors use some statistical modeling to correct for that. The authors studied patients with head and neckAbbreviated Injury Scale scores of three or greater. The study is provocative but does carry some limitations, some of which the authors acknowledge. The retrospective nature of the study being the largest one. Theories are put forth to explain the difference such as the limited experience of prehospital personnel in obtaining an airway, and the use of pharmaceutical adjuncts available in the hospital. No data was available to the registry about failed pre-hospital intubations attempts, which would obviously worsen outcomes.
The paper and an accompanying editorial suggest:
The current findings, along with the results from other recent studies, should compel us to aggressively investigate out-of-hospital intubation for severe traumatic brain injury. Wang et all note that "... a logical-but risky and controversial-direction would be to conduct a controlled clinical trial randomizing patients with traumatic brain injury to either out-of-hospital endotracheal intubation or no out-of-hospital endotracheal intubation." We must ask, risk to whom? The mounting body of evidence suggests that out-of-hospital endotracheal intubation for patients with traumatic brain injury is not beneficial, and may be harmful. If our current out-of-hospital airway management protocols, or the training and supervision of our out-of-hospital providers results in worse outcomes for patients with traumatic brain injury, there is more "risk" with continuing business as usual than in performing definitive research in this area.
Such a "risky and controversial" trial concerning resuscitation methods has been done before and the subject is still one of debate ten years later. I agree with the editorialist, if things are this bad now, what have we got to lose by putting on a trial?
Weblog Commenting and Trackback by HaloScan.com

This page is powered by Blogger. Isn't yours?