LETTERS
AAMS response to Habib et al, Probable cause in helicopter emergency medical services crashes To the Editor: n light of recently published research,1 the Association of Air Medical Services (AAMS) would like to address concerns raised by the study and emphasize the industry’s safety accomplishments and enhancements not fully recognized in the research. Since 2009, the air medical industry has substantially improved its safety culture through, among other things, a mix of technologic advancements, adoption of safety management systems, volunteer quality improvement programs, and other safetyminded policies and procedures. The study cites a variety of outdated research that does not take into account these advancements. Furthermore, it oversimplifies the myriad business models in our industry by categorizing accident data by ‘‘commercial,’’ ‘‘notfor-profit,’’ and ‘‘public safety’’ providers.1 The study’s methodology uses an overly broad definition of ‘‘commercial’’ Helicopter Emergency Medical Services (HEMS) by including those not-for-profit services that use a for-profit aviation vendor. However, it also uses an overly narrow definition of ‘‘public safety’’ flights by excluding all other public safety aviation profiles other than emergency medical flights. Despite the discrepancies in these definitions, the study makes no mention of the relative flight volumes of these differing business models. The data analysis is based on raw accident numbers and subjective surveys with no recognition that ‘‘public safety HEMS’’ flights are an extremely small percentage of overall HEMS flights. AAMS also notes that public safety aviation operators are not subject to the more stringent Federal Aviation Administration (FAA) Part 135 regulations that apply to air medical and other on-demand aviation providers and that they are not subject to the air medical specific A021 Operations Specifications. We have and continue to believe that public safety HEMS transports should be operated under the same, more stringent, FAA safety standards as the air medical community. Perhaps most troubling, the study seems to imply that the safety records of commercial providers is directly affected by fiduciary pressures.1 ‘‘Fiduciary care’’ is a fundamental business concept. All air medical providers
I
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TO THE
EDITOR
have financial responsibilities whether they answer to owners, shareholders, a nonprofit board of directors, or taxpayers. The same holds true for hospitals, doctors, other medical providers, and any other for-profit or not-forprofit business of any kind. Despite the implications set forth in the study, the air medical transport industry, as a whole, has voluntarily invested (and continues to invest) hundreds of millions of dollars in operational and safety improvements such as night vision goggles, helicopter terrain awareness warning systems, operational control centers, autopilot systems, as well as climate control, flight data monitoring, and quality assurance programs. In addition, the industry has implemented vigorous Safety Management Systems and vastly improved education and training in the area of human factors. The advent of Safety Management Systems and the ongoing education and training designed to combat complacency and increase personal accountability have resulted in an industry-wide safety culture that reaches across all business models. The vast majority of these safety improvements have been adopted voluntarily and unilaterally, well ahead of any FAA mandate. We worked constructively with the FAA to support the publication of its Rule entitled, ‘‘Helicopter Air Ambulance, Commercial Helicopter, and Part 91 Helicopter Operations.’’ That Rule was publically released in February of 2014, following a rulemaking process that took more than 3 years to complete. We are continuing to work with the FAA to ensure a successful and productive implementation of this important safety regulation. Rest assured, safety remains the top priority of the air medical community. AAMS is committed to working with industry, regulators, and legislators to ensure the safest possible operating environment for pilots, medical crew, and the nearly 400,000 patients-in-need who rely on the lifesaving services provided by our members each year.
Richard Sherlock, MA Association of Air Medical Services (AAMS) and MedEvac Foundation International Alexandria, Virginia
REFERENCE 1. Habib FA, Shatz D, Habib AI, Bukur M, Puente I, Catino J, Farrington R. Probable cause in helicopter emergency medical services crashes: what role does ownership play? J Trauma Acute Care Surg. 2014;77(6):989Y993.
Rethinking ‘‘time to rethink’’ distracting injuries e were pleased to see Rose et al.1 validate the sensitivity of ‘‘distracting painful injury’’ (DPI) on identifying cervical spine injury (CSI). We are disappointed, however, that they then went on to reach a conclusion that is unsupported by their own data. It is, first of all, important to note that the definition of DPI used in their study is very different from the one we used in NEXUS.2 We do not believe it is reasonable, or possible, to define a list of specific injuries that qualify, or fail to qualify, as DPI. Some patients with long bone fracture, for example, experience only minor pain and are well aware of other injuries; at the same time, there are trauma patients who are obviously in severe pain and focus only on a single injury (e.g., road burn, a bad corneal abrasion, or a dislocated joint, etc.) not easily included in any such list as the one created by these investigatorsVor even a list far more exhaustive than theirs. We therefore stress the importance of having DPI be defined by the clinician based on the clinician’s judgment, at the bedside, that the patient in question was so ‘‘distracted’’ by some other injury and might not recognize their cervical spine injury. Using such a definition, DPI proved to be an essential independent criterion, in NEXUS, to allow safe clinical clearance without imaging.3 Despite this difference in definitions, our findings in NEXUS, in a cohort of more than 34,000 patients, are not importantly at odds with those of Rose et al.1 We enrolled such a large group in NEXUS because we knew that we would need to include a substantial number of patients (at least 756) with CSI to be able to calculate the sensitivity of our decision instrument with high confidence. Among the 814 patients with CSI, our calculated sensitivity of DPI was essentially 99%, which is well within the confidence interval for the results found by Rose et al.1 We did find that the large majority of patients with CSI could be identified on the basis of the four other NEXUS criteria I but even so, given the large number of patients in NEXUS who had CSI, failure to include DPI among the criteria would have resulted in failure to identify 45 patients with injury.3 The fact that exclusion of DPI as a criterion for clinical clearance of CSI still allows for a very high negative predictive value (NPV) demonstrates why NPV is not an appropriate end point measure; in fact, the NPV of no criteria at all is higher than 97%Vsince fewer than 3% of patients being
W
J Trauma Acute Care Surg Volume 78, Number 5
Copyright © 2015 Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited.
J Trauma Acute Care Surg Volume 78, Number 5
evaluated have CSI! Thus, the wonderfulsounding NPV is more dependent on the rarity of injury than it is on the accuracy of such a strategy, and exclusion of DPI would indeed lead to major harm in a small but not insignificant number of patients. We applaud continued efforts to study how best to limit imaging of the cervical spine in trauma patients but feel it is important for readers to understand the danger of making overbroad conclusions based on an inadequate cohort of study subjects. We believe that there is no evidence in the study by Rose et al.1 that should dissuade clinicians from continuing to use ‘‘distracting painful injury’’Vas defined
Letters to the Editor
in the NEXUS studyVas one of the essential criteria on which to base clinical clearance. The authors declare no conflicts of interest.
Jerome R. Hoffman, MA, MD William R. Mower, MD, PhD UCLA School of Medicine Los Angeles, California
REFERENCES 1. Rose MK, Rosal LM, Gonzalez RP, Rostas JW, Baker JA, Simmons JD, Frotan MA, Brevard SB.
Clinical clearance of the cervical spine in patients with distracting injuries: it is time to dispel the myth. J Trauma Acute Care Surg. 2012;73: 498Y502. 2. Hoffman JR, Mower WR, Wolfson AB, Todd K, Zucker MI. Validity of a set of clinical criteria to rule out injury to the cervical spine injury in patients with blunt trauma: The National Emergency X-radiography Utilization Study (NEXUS). New England Journal of Medicine. 2000;343:94Y99. 3. Panacek EA, Mower WR, Holmes JF, Hoffman JR, NEXUS Group. Test performance of the individual NEXUS low-risk clinical screening criteria for cervical spine injury. Ann Emerg Med. 2001;38:22Y25.
* 2015 Wolters Kluwer Health, Inc. All rights reserved.
Copyright © 2015 Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited.
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AAMS response to Habib et al, Probable cause in helicopter emergency medical services crashes To the Editor: n light of recently published research,1 the Association of Air Medical Services (AAMS) would like to address concerns raised by the study and emphasize the industry’s safety accomplishments and enhancements not fully recognized in the research. Since 2009, the air medical industry has substantially improved its safety culture through, among other things, a mix of technologic advancements, adoption of safety management systems, volunteer quality improvement programs, and other safetyminded policies and procedures. The study cites a variety of outdated research that does not take into account these advancements. Furthermore, it oversimplifies the myriad business models in our industry by categorizing accident data by ‘‘commercial,’’ ‘‘notfor-profit,’’ and ‘‘public safety’’ providers.1 The study’s methodology uses an overly broad definition of ‘‘commercial’’ Helicopter Emergency Medical Services (HEMS) by including those not-for-profit services that use a for-profit aviation vendor. However, it also uses an overly narrow definition of ‘‘public safety’’ flights by excluding all other public safety aviation profiles other than emergency medical flights. Despite the discrepancies in these definitions, the study makes no mention of the relative flight volumes of these differing business models. The data analysis is based on raw accident numbers and subjective surveys with no recognition that ‘‘public safety HEMS’’ flights are an extremely small percentage of overall HEMS flights. AAMS also notes that public safety aviation operators are not subject to the more stringent Federal Aviation Administration (FAA) Part 135 regulations that apply to air medical and other on-demand aviation providers and that they are not subject to the air medical specific A021 Operations Specifications. We have and continue to believe that public safety HEMS transports should be operated under the same, more stringent, FAA safety standards as the air medical community. Perhaps most troubling, the study seems to imply that the safety records of commercial providers is directly affected by fiduciary pressures.1 ‘‘Fiduciary care’’ is a fundamental business concept. All air medical providers
I
1066
TO THE
EDITOR
have financial responsibilities whether they answer to owners, shareholders, a nonprofit board of directors, or taxpayers. The same holds true for hospitals, doctors, other medical providers, and any other for-profit or not-forprofit business of any kind. Despite the implications set forth in the study, the air medical transport industry, as a whole, has voluntarily invested (and continues to invest) hundreds of millions of dollars in operational and safety improvements such as night vision goggles, helicopter terrain awareness warning systems, operational control centers, autopilot systems, as well as climate control, flight data monitoring, and quality assurance programs. In addition, the industry has implemented vigorous Safety Management Systems and vastly improved education and training in the area of human factors. The advent of Safety Management Systems and the ongoing education and training designed to combat complacency and increase personal accountability have resulted in an industry-wide safety culture that reaches across all business models. The vast majority of these safety improvements have been adopted voluntarily and unilaterally, well ahead of any FAA mandate. We worked constructively with the FAA to support the publication of its Rule entitled, ‘‘Helicopter Air Ambulance, Commercial Helicopter, and Part 91 Helicopter Operations.’’ That Rule was publically released in February of 2014, following a rulemaking process that took more than 3 years to complete. We are continuing to work with the FAA to ensure a successful and productive implementation of this important safety regulation. Rest assured, safety remains the top priority of the air medical community. AAMS is committed to working with industry, regulators, and legislators to ensure the safest possible operating environment for pilots, medical crew, and the nearly 400,000 patients-in-need who rely on the lifesaving services provided by our members each year.
Richard Sherlock, MA Association of Air Medical Services (AAMS) and MedEvac Foundation International Alexandria, Virginia
REFERENCE 1. Habib FA, Shatz D, Habib AI, Bukur M, Puente I, Catino J, Farrington R. Probable cause in helicopter emergency medical services crashes: what role does ownership play? J Trauma Acute Care Surg. 2014;77(6):989Y993.
Rethinking ‘‘time to rethink’’ distracting injuries e were pleased to see Rose et al.1 validate the sensitivity of ‘‘distracting painful injury’’ (DPI) on identifying cervical spine injury (CSI). We are disappointed, however, that they then went on to reach a conclusion that is unsupported by their own data. It is, first of all, important to note that the definition of DPI used in their study is very different from the one we used in NEXUS.2 We do not believe it is reasonable, or possible, to define a list of specific injuries that qualify, or fail to qualify, as DPI. Some patients with long bone fracture, for example, experience only minor pain and are well aware of other injuries; at the same time, there are trauma patients who are obviously in severe pain and focus only on a single injury (e.g., road burn, a bad corneal abrasion, or a dislocated joint, etc.) not easily included in any such list as the one created by these investigatorsVor even a list far more exhaustive than theirs. We therefore stress the importance of having DPI be defined by the clinician based on the clinician’s judgment, at the bedside, that the patient in question was so ‘‘distracted’’ by some other injury and might not recognize their cervical spine injury. Using such a definition, DPI proved to be an essential independent criterion, in NEXUS, to allow safe clinical clearance without imaging.3 Despite this difference in definitions, our findings in NEXUS, in a cohort of more than 34,000 patients, are not importantly at odds with those of Rose et al.1 We enrolled such a large group in NEXUS because we knew that we would need to include a substantial number of patients (at least 756) with CSI to be able to calculate the sensitivity of our decision instrument with high confidence. Among the 814 patients with CSI, our calculated sensitivity of DPI was essentially 99%, which is well within the confidence interval for the results found by Rose et al.1 We did find that the large majority of patients with CSI could be identified on the basis of the four other NEXUS criteria I but even so, given the large number of patients in NEXUS who had CSI, failure to include DPI among the criteria would have resulted in failure to identify 45 patients with injury.3 The fact that exclusion of DPI as a criterion for clinical clearance of CSI still allows for a very high negative predictive value (NPV) demonstrates why NPV is not an appropriate end point measure; in fact, the NPV of no criteria at all is higher than 97%Vsince fewer than 3% of patients being
W
J Trauma Acute Care Surg Volume 78, Number 5
Copyright © 2015 Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited.
J Trauma Acute Care Surg Volume 78, Number 5
evaluated have CSI! Thus, the wonderfulsounding NPV is more dependent on the rarity of injury than it is on the accuracy of such a strategy, and exclusion of DPI would indeed lead to major harm in a small but not insignificant number of patients. We applaud continued efforts to study how best to limit imaging of the cervical spine in trauma patients but feel it is important for readers to understand the danger of making overbroad conclusions based on an inadequate cohort of study subjects. We believe that there is no evidence in the study by Rose et al.1 that should dissuade clinicians from continuing to use ‘‘distracting painful injury’’Vas defined
Letters to the Editor
in the NEXUS studyVas one of the essential criteria on which to base clinical clearance. The authors declare no conflicts of interest.
Jerome R. Hoffman, MA, MD William R. Mower, MD, PhD UCLA School of Medicine Los Angeles, California
REFERENCES 1. Rose MK, Rosal LM, Gonzalez RP, Rostas JW, Baker JA, Simmons JD, Frotan MA, Brevard SB.
Clinical clearance of the cervical spine in patients with distracting injuries: it is time to dispel the myth. J Trauma Acute Care Surg. 2012;73: 498Y502. 2. Hoffman JR, Mower WR, Wolfson AB, Todd K, Zucker MI. Validity of a set of clinical criteria to rule out injury to the cervical spine injury in patients with blunt trauma: The National Emergency X-radiography Utilization Study (NEXUS). New England Journal of Medicine. 2000;343:94Y99. 3. Panacek EA, Mower WR, Holmes JF, Hoffman JR, NEXUS Group. Test performance of the individual NEXUS low-risk clinical screening criteria for cervical spine injury. Ann Emerg Med. 2001;38:22Y25.
* 2015 Wolters Kluwer Health, Inc. All rights reserved.
Copyright © 2015 Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited.
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