Tag Archives: helicopter

General

Who Travels By Air?

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Getting seriously injured trauma patients to a trauma center quickly is generally believed to be a good thing. And helicopters are usually faster than ground ambulances. So sending severely injured patients by air is a good thing, right?

Not quite so fast, there. There are other concerns as well. Helicopter transport is significantly more expensive. Quarters are very cramped, and you can’t just pull off to the side of the road if major patient or equipment problems arise. And has anybody really shown a survival benefit?

Although there is a (relatively) standard national trauma triage protocol from the CDC that indicates which patients should be transported to a trauma center, there is no standard protocol for who should be transported by air. The University of Rochester School of Medicine looked at 2007 transport data from the National Trauma Databank and tried to determine if the CDC protocol could be adapted to air transport as well.

Over 250,000 patient records were included in the study. As would be expected, patients flown by helicopter tended to be more severely injured, needed intubation more often, and were admitted to an ICU and stayed in the hospital longer. Average transport time for the helicopter was longer (60 mins vs 43 mins), implying longer distance traveled. Using a regression analysis, the authors found that the following subsets of patients had better survival with helicopter transport:

  • Penetrating injury
  • GCS < 14
  • Resp rate <10 or >29
  • Age >55
  • Any one physiologic criterion and any one anatomic criterion from the CDC protocol

Bottom line: A more standardized set of air transport criteria is needed. Some studies have found that as many as 50% of patients in some communities are flown who do not meet local air transport rules. Time and distance also need to be taken into account, since these will vary widely between rural and less rural areas. This study begins to lay an objective framework of criteria that can be incorporated into a more uniform set of guidelines.

Related posts:

Reference: The National Trauma Triage Protocol: Can this tool predict which patients with trauma will benefit from helicopter transport? J Trauma 73(2):319–325, 2012.

General

Helicopter Transport of Trauma Patients Saves Lives

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Helicopter EMS (HEMS) transport of trauma patients is used primarily to decrease the amount of time between injury and arrival at the trauma center. Unfortunately, efficacy studies have provided conflicting answers as to whether this is actually true. Last year, the CDC completed a large sample study of this issue using the National Trauma Data Bank (NTDB) in an attempt to determine if HEMS flights are effective.

Using almost 150,000 entries in the NTDB for 2007, they were able to isolate over 56,000 adult records with complete data points. They looked for mortality patterns based on age, injury severity, and revised trauma score, comparing patients who were transported by air vs ground.

They found the following:

  • Odds of dying in-hospital were 39% lower overall when transported by helicopter
  • This survival advantaged disappeared for patients age 55 and older, possibly because of decreased reserve, comorbidities, more complications, or medications that interfere with successful resuscitation
  • Regardless of type of transport, males always fared worse than females

Bottom line: This is a large and intriguing study. About 85% of the US population has access to a Level I or II trauma center within an hour. However, a third of those can only get there in that period of time if transported by air. This mode of transport has a significantly lower mortality rate. However, there are cost and safety considerations as well. The key now is to figure out which patients will have the best outcomes after air transport. This will require more work, looking at more than just mortality (e.g. disability, complications). And what’s the deal with men having poorer outcomes???

Reference: Reduced mortality in injured adults transported by helicopter emergency medical services. Prehospital Emerg Care 15(3):295-302, 2011.

General

Trauma Survival and Air vs Ground Transport

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Wartime experience has shown that rapid transport from the battlefield scene of injury to definitive care dramatically improves survival. This has been translated into civilian trauma care by making helicopter transport to a trauma center more widely available. But this resource is still somewhat limited, and very expensive compared to ground EMS transport. Is this expense warranted, or in other words, does it improve survival?

Many have tried to answer this question. Several of these studies did show improved survival with air transport, but most had significant flaws that made their conclusions hard to interpret. The current issue of JAMA has published an article from MIEMSS and Johns Hopkins that tries to do it right.

The authors used the National Trauma Data Bank (1.8M records) and whittled it down to 223K by using pertinent exclusion criteria. About 25% were transported by air and 72% were taken to Level I centers (vs Level II). A sophisticated regression model was used to adjust for missing data and clustering by trauma centers.

They found that there is roughly a 1.5% survival advantage in taking patients to trauma centers by air. About 65 patients need to be transported to a Level I center, or 69 patients to a Level II center, to save a life. There are some issues with the statistics, primarily due to the nature of the NTDB data, but overall the paper is nicely done.

Bottom line: It looks like helicopter transport of seriously injured trauma patients conveys a very small survival advantage. However, this does not mean that everybody now needs to be flown in. This is not an ideal world, and not everybody is in an area that can provide such transport. Furthermore, in many areas ground EMS is still faster than air. And finally, air transport is much more expensive than the incremental survival increase may be worth. We will have to come to grips as a society to figure out what we can really afford.

Reference: Association between helicopter vs ground emergency medical services and survival for adults with major trauma. JAMA 307(15):1602-1610, April 18, 2012.

General

Helicopter Transport of Trauma Patients Saves Lives

Leave a comment

Helicopter EMS (HEMS) transport of trauma patients is used primarily to decrease the amount of time between injury and arrival at the trauma center. Unfortunately, efficacy studies have provided conflicting answers as to whether this is actually true. Last year, the CDC completed a large sample study of this issue using the National Trauma Data Bank (NTDB) in an attempt to determine if HEMS flights are effective.

Using almost 150,000 entries in the NTDB for 2007, they were able to isolate over 56,000 adult records with complete data points. They looked for mortality patterns based on age, injury severity, and revised trauma score, comparing patients who were transported by air vs ground.

They found the following:

  • Odds of dying in-hospital were 39% lower overall when transported by helicopter
  • This survival advantaged disappeared for patients age 55 and older, possibly because of decreased reserve, comorbidities, more complications, or medications that interfere with successful resuscitation
  • Regardless of type of transport, males always fared worse than females

Bottom line: This is a large and intriguing study. About 85% of the US population has access to a Level I or II trauma center within an hour. However, a third of those can only get there in that period of time if transported by air. This mode of transport has a significantly lower mortality rate. However, there are cost and safety considerations as well. The key now is to figure out which patients will have the best outcomes after air transport. This will require more work, looking at more than just mortality (e.g. disability, complications).

Reference: Reduced mortality in injured adults transported by helicopter emergency medical services. Prehospital Emerg Care 15(3):295-302, 2011.

General

Helicopter Transport and Civilian Trauma

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Military helicopter experience led to widespread adoption in the US for civilian trauma beginning in the 1970s. This has had the significant side effect of extending the reach of trauma centers to a significant percentage of the US population. But because of safety considerations and concerns about appropriate use, the overall benefit continues to be questioned.

Most existing studies have been small, single institution projects. Researchers at the University of Rochester designed a very large study using the National Trauma Databank. They identified over 250,000 patients transported from the injury scene, 16% of whom were transported by ‘copter, the remainder by ground. 

Patients transported by air were more severely injured and were more likely to have a severe head injury or abnormal vital signs. They also had longer hospital and ICU stays, and were more likely to require a ventilator or emergency surgery.

Despite the fact that response and scene times were longer for helicopter transports, air transport was a predictor of survival when injury severity was taken into consideration. This type of study can’t tell why survival is better, but possibilities include distance traveled and a higher level of care provided by air EMS personnel. Aeromedical EMS personnel are more likely to trained to perform advanced techniques such as intubation, crich, and transfusion, and generally have more experience with trauma patients.

Use of this scarce resource for trauma patient transport remains expensive, and as recent accident statistics imply, somewhat dangerous. Trauma centers and systems need to develop evidence-based guidelines that use helicopters intelligently for benefit of the patient, not the aeromedical service owners.

Reference: Helicopters and the civilian trauma system: national utilization patterns demonstrate improved outcomes after trauma injury. J Trauma 69(5):1030-6, 2010.