Clinical Impact of Cabin Altitude Restriction Following Aeromedical Evacuation.

Combat medical care relies on aeromedical evacuation (AE). Vital to AE is the validating flight surgeon (VFS) who warrants a patient is "fit to fly." To do this, the VFS considers clinical characteristics and inflight physiological stressors, often prescribing specific interventions such as a cabin altitude restriction (CAR). Unfortunately, limited information is available regarding the clinical consequences of a CAR. Consequently, a dual case-control study (CAR patients versus non-CAR patients and non-CAR patients flown with a CAR versus non-CAR patients) was executed. Data on 1,114 patients were obtained from TRANSCOM Regulating and Command and Control Evacuation System and Landstuhl Regional Medical Center trauma database (January 2007 to February 2008). Demographic and clinical factors essentially showed no difference between groups; however, CAR patients appeared more severely injured than non-CAR patients. Despite being sicker, CAR patients had similar clinical outcomes when compared with non-CAR patients. In contrast, despite an equivocal severity picture, the non-CAR patients flown with a CAR had superior clinical outcomes when compared with non-CAR patients. It appeared that the CAR prescription normalized severely injured to moderately injured and brought moderately injured into a less morbid state. These results suggest that CAR should be seriously considered when evacuating seriously ill/injured patients.

A Retrospective Cohort Analysis of Battle Injury Versus Disease, Non-Battle Injury-Two Validating Flight Surgeons' Experience.

Today, military combat medical care is the best it has ever been. Regulated U.S. Air Force aeromedical evacuation (AE) is one important reason. The Theater Validating Flight Surgeon (TVFS) validates that a patient is ready for flight. Two TVFSs' experiences, successively deployed in 2007, are the focus of this study. A unique operational worksheet used to manage the AE queue was used for approximately 5 months. A descriptive analysis of the worksheet's 1,389 patients found the majority male (94%), median age 30 years, and mostly Army enlisted soldiers (63%). U.S. civilians made up 9%. Battle Injury (55%) surpassed Disease, Non-Battle Injury (45%); most frequently seen were extremity injuries (73%) and cardiac illness (31%), respectively. Common to both Battle Injury and Disease, Nonbattle Injury were several TVFS prescriptions including no "remain overnights" (79%), head of bed elevation (78%), cabin altitude restriction (57%), no stops (44%), Critical Care Air Transport Team (27%), and supplemental oxygen (22%). This study is a first look at the TVFS experience and it offers up an initial accounting of the TVFS clinical and prescriptive practices. It is also a jumping point for future TVFS investigations using the available AE databases.

Complication Rates in Altitude Restricted Patients Following Aeromedical Evacuation.

INTRODUCTION: Military aeromedical evacuation, especially that associated with the present Middle East conflict, is seeing increasing research. This ecological study initiates research into the validating flight surgeon by looking at cabin altitude restriction (CAR), arguably the validating flight surgeon's prescription with the highest patient-mission impact, and its association with postflight complications. METHODS: CAR rates from January 2006 through February 2008 were determined from the U.S. Transportation Command Regulating and Command and Control Evacuation System database. Postflight complication rates-the rate of patients with postflight complications (PFC) and the postflight complications per 100 patients (PFC-100)-from January 2007 through June 2008 were calculated from the Landstuhl Regional Medical Center trauma database. CAR and complication rates were examined before, during, and after the authors' deployment. In addition, the relationship between CAR and postflight complication rates was investigated; as the rates were nonlinear, a Spearman correlation was performed. RESULTS: CAR rates during the authors' deployments were significantly up compared to the authors' predecessors or successors; their predecessors and successors did not differ statistically. Likewise, the PFC rate during the authors' deployments was significantly lower than that of the before or after time frames. Furthermore, a statistically significant inverse relationship between CAR and PFC rates (Spearman rho = -0.587) as well as CAR and PFC-100 rates (Spearman rho = -0.568) was demonstrated. DISCUSSION: CAR rate was inversely correlated to PFC and PFC-100 rates. This finding suggests that aggressive prescribing of CARs may have a salutary effect on postflight complication rates and bears further investigation.

Investigation of Self-Reported Musculoskeletal Injuries on Post-Deployment Health Assessment Forms for Aeromedical Evacuation Personnel.

Musculoskeletal injuries (MSIs) are a concern for the military community because of medical expenses, possible disability, and separation from the military. This study investigated the prevalence of MSIs in deployed aeromedical evacuation (AE) populations reported on Post-Deployment Health Assessment (PDHA) forms. A secondary aim was to examine the relationship between the occurrence of self-reported MSIs on PDHAs and a subsequent medical diagnosis. Flight nurses (Air Force Specialty Code [AFSC] 46F) and AE technicians (AETs) (AFSC 4N0 with a flight duty badge) who completed a PDHA during 2008-2010 were investigated. Data from the test population were compared with a control group of deployed ground-based counterparts. During this time period, 1,366 and 1,959 PDHAs were completed by the AE nursing and AET groups, respectively. At least 1 MSI was reported by 18% of AE nurse and 19% of AET compared with 23% of non-AE nurse and 25% of non-AET PDHAs. Of these individuals with reported MSIs, 35% and 44% of AE nurse and AET PDHAs, respectively, had a diagnosis matching their MSIs. Identifying the prevalence of MSIs in the unique AE environment can lead to the development of preventative and ergonomic solutions, minimizing the risk of MSIs and improving mission success.

Records review of musculoskeletal injuries in aeromedical evacuation personnel.

BACKGROUND: Aeromedical evacuation providers care for patients during air transport. By applying standard medical practices, oftentimes developed for ground care, these practitioners perform their mission duties under additional physical stress in this unique medical environment. Awkward postures and excessive forces are common occurrences among personnel operating in this domain. Additionally, anecdotal reports highlight the risk of developing musculoskeletal injuries for these providers. Currently, there is limited research focusing on musculoskeletal injuries in aeromedical evacuation providers. PURPOSE: To determine the prevalence of musculoskeletal injuries and associated symptoms in aeromedical evacuation providers to understand the risk and burden of these injuries to military personnel. METHODS: This study utilized a retrospective review of military medical records containing ICD-9 codes to investigate the incidence of musculoskeletal injuries within flight nurses and medical technicians compared to their non-flying counterparts from 2006 through 2011. Data were analyzed from 2013 through 2014. RESULTS: Although musculoskeletal injuries were identified within the test populations, results showed fewer injuries for aeromedical evacuation populations compared to non-aeromedical evacuation counterparts. CONCLUSIONS: One contributing factor may be a potential under-reporting of musculoskeletal injuries resulting from the fear of being placed on limited flying status. As flyers, aeromedical evacuation personnel must undergo yearly medical examinations and complete training courses that emphasize proper lifting techniques and physical requirements necessary for the safe and efficient transport of patients on various platforms. These additional requirements may create a healthy worker effect, likely contributing to lower musculoskeletal injuries.

Safe-to-fly test and evaluation of fatigue research study test devices.

INTRODUCTION: The U.S. Air Force (USAF) School of Aerospace Medicine is conducting a fatigue research study titled "Assessment of Fatigue in Deployed Critical Care Air Transport Team (CCATT) Crews" using two electronic devices onboard USAF aircraft during actual CCATT missions. Both devices were subjected to testing to support a safe-to-fly (STF) recommendation prior to their use in flight. The purpose of the test and evaluation process was to ensure the devices can be safely operated in flight without posing a hazard to the research participant, crewmembers, or aircraft during an actual mission. The goal of this article is to outline the key factors involved in the STF certification process. METHODS: This paper discusses the test and evaluation process for making STF recommendation and presents the rationale for selecting the applicable tests and test susceptibilities. The following STF tests were conducted: baseline assessment, vibration, electromagnetic interference, altitude, rapid decompression, and explosive atmosphere. Acceleration testing, environmental (temperature and humidity) testing, and in-flight assessments were deemed not required for the STF certification of these devices. RESULTS: Based on the results of this study, the devices were deemed safe to the flight crew and aircraft. CONCLUSIONS: The outcome of this study was subsequent approval letters issued by the respective airframe system program offices to allow use of these devices onboard USAF C-130 E/H/J, C-17, and KC-135 aircraft.

Pneumatic muscle actuator for resistive exercise in microgravity: test with a leg model.

INTRODUCTION: A proof-of-concept demonstration is described in which a DC servomotor (simulating the quadriceps of a human operator) rotated a pulley 90 degrees (simulating knee extension). A pneumatic muscle actuator (PMA) generated an opposing force (antagonist) to the rotating pulley. One application of such a device is for use in microgravity environments because the PMA is compact, simple, and of relatively small mass (283 g). In addition, the operator can set a computer-controlled force-level range in response to individual user changes in exercise conditioning over time. METHODS: A PMA was used in this study and interacted with a DC servomotor. For each trial, the PMA contracted in response to internal pressure. An input voltage profile activated the DC servomotor, resulting in the following three phases: an isokinetic counterclockwise pulley rotation of 90 degrees over 5 s (Phase I), the position was held for 5 s (Phase II), and an isokinetic clockwise rotation of 90 degrees over 5 s (Phase III). Root mean square error (RMSE) values were used to evaluate the pulley rotation. RESULTS: For Phase I, when the PMA pressures (in kPa) were 300, 450, and 575, the percent RMSE, respectively, were 5.24, 6.23, and 4.59. For Phase II, the percent RMSE were 2.81, 2.57, and 5.63, respectively. For Phase III, the percent RMSE were 5.69, 2.63, and 3.30, respectively. DISCUSSION: This study presents a demonstration of a PMA device that can enhance exercise by providing a wide range of resistive loads.

Structure and dynamics of surfactant interfaces in organically modified clays.

Organic modification of clays with surfactants is required for the preparation of polymer-clay nanocomposites for a variety of applications. We have studied the structure and dynamics of interfaces in synthetic clays modified with phosphonium surfactants. The chemical shifts, line widths, and relaxation times measured by 31P, 13C, and 1H NMR and the relaxation times measured by impedance spectroscopy allow us to monitor the dynamics over a wide range of time scales. The results show that the phosphonium headgroup is most restricted and that the mobility increases with increasing separation from the clay surface. The carbon chemical shifts show that the 16-carbon and 12-carbon surfactant tails of hexadecyltributyl phosphonium and dodecytriphenyl phosphonium are disordered at the interface and experience mobility over a range of time scales. The dynamics depend most strongly on the structure of the surfactant headgroup, and tributylphosphoniums are more mobile than the triphenylphosphoniums. Two dimensional chemical shift anisotropy spin exchange experiments show that the phosphorus atoms in the triphenylphosphonium surfactant are immobile on the clay surface on a 1 s time scale. The dynamics measured by impedance spectroscopy show a similar dependence on headgroup structure, even though the processes occur on very different time scales and length scales. The relationship between the structure and dynamics of the interface and the properties of composites are considered.