LA Times: Trauma patients more likely to survive if rescued by helicopter
MSNBC: Helicopter beats ambulance for trauma patients
US News: Helicopter Beats Ground Transport for Trauma Victims: Study
Scientific American: Helicopters Save Lives for Serious Trauma Victims
What I am going to do is point out the many flaws in the paper and give you some information about the other side of the story. As is true of nearly all papers, you should read the full text, not just the abstract.
The paper looked at outcomes for 61,909 trauma patients transported by helicopter and 161,566 patients were transported by ground ambulances. Although the unadjusted results showed a higher mortality rate for those transported by helicopter, they were also more seriously injured. The adjusted mortality rates favored the helicopter by a statistically significant but small 1.5%. The number needed to treat was 65 to save 1 life and the cost for saving 1 life was estimated at $325,000, the same figure as heart surgery.
The authors used the National Trauma Data Bank [NTDB] as their source. More than 900 of the 6000 or so hospitals in the US voluntarily contribute data. Although the NTDB is said to contain more complete data than in prior years, some issues remain.
For example, the paper started with records of more than 1.8 million patients. Various appropriate exclusions, such as restricting the analysis to seriously injured patients, whittled the number down to 978,000. Over 115,000 records were then excluded because information about their method of transportation was not reported. More than 102,000 patients not treated at Level I or II trauma centers were omitted too. Of the patients included, some 38% were missing more than 40% of the data that was supposed to have been submitted. Remember, this is the so-called “improved quality” NTDB data.
This was a retrospective study and the authors point out that no accepted nationwide guidelines for first responders on the ground to call in a helicopter exist.
The cost analysis was done using information from the state of Maryland, which uses state police helicopters. At $5000 per flight, it is one of the least expensive medical helicopter services in the nation. Other cost estimates range from $5000 to well over $15,000 per flight. And some studies have shown that nearly half of all patients transported by helicopter are not even admitted to the hospital. The costs of those flights, had they to be included in the calculation, would certainly increase the cost per life saved.
There is also the issue of medical helicopter safety. Many crashes occur every year with several resulting in the deaths of patients and crew. [National Transportation Safety Board Report, page 32].
Should the safety record and the number of patients unnecessarily transported by helicopter be considered in the number needed to treat?
The authors mentioned several limitations of their study including the following:
They imputed [translation: made up] data for variables where data was missing in no more than 20% of the records. There is selection bias because hospitals submitting data to the NTDB are likely doing better than those which do not submit data. It is unknown whether the modest survival improvement is due to the helicopter or the fact that helicopters are usually staffed with MDs, nurses and advanced paramedics as opposed to paramedics and EMTs on ground ambulances.
The literature is replete with papers stating that helicopters do not increase survival rates. In fact one that was presented at the American Association for the Surgery of Trauma just appeared last month in the Journal of Trauma. Other than prehospital time which is significant longer for helicopter patients, there were no differences in any parameters including survival.
In the discussion of this paper, a well-known trauma thought leader, Dr. Ken Mattox, said, “So my question is, is it time for the ROC [Resuscitation Outcome Consortium] or this organization [AAST] or organized medicine to take the power of our convictions and our evidence and make a policy statement on this very expensive advertising mode that does not really alter outcomes?
Bottom line. The study left out almost as many patients [mode of transport unknown and those not taken to a level I or II trauma center] as it included. Many of the patient records include in the study had missing data. The cost per life saved was calculated to be as favorable as possible and did not include the substantial costs of unnecessary flights. The abysmal safety record of medical helicopters was not mentioned. The helicopter may not be the factor leading to the modest [1.5%] increase in survival rate, but rather it may be the way they are staffed.
How do the headlines look now?