Fatalities in Swedish fire-related car crashes from a toxicologic perspective.

Objective: Vehicle materials developments raise concerns about new patterns of vehicle fire toxic gas emissions. This study aimed to describe toxicologic components in a recent material of fatal car crashes on Swedish roads in which the vehicle caught fire and compare the results to a previous material.Methods: Retrospective registry study. All fatal car crashes with fire in Sweden 2009-2018 were extracted from the Swedish Transport Administration's In-Depth Studies Database and compared with an earlier study of the time period 1998-2008.Results: A total of 79 crashes and 94 fatalities were included. Carbon monoxide (COHb) blood levels >10% were found in 13 cases. Hydrogen cyanide (HCN) blood levels 0.1-1.7 µg/g were found in 10 cases. In 29 of the cases the person had a blood alcohol level (BAC) >0.2‰, which is the legal driving limit in Sweden. A total of 15 people died due to burn injuries and 2 individuals died due to toxic gas emissions without any other fatal traumatic injury. Total number of deaths in fire-related crashes halved from 181 (1998-2008) to 94 (2009-2018) but the percentage of fatalities in burning vehicles was unaltered (5% vs. 6%). The proportion of fatalities with HCN in the blood increased from 2% between 1998-2008 to 10% during 2009-2018 (p = 0.006). The age of the car involved in a crash increased by 0.26 years per calendar year (p = 0.001).Conclusions: The proportion of fatalities with measured levels of HCN in the blood has increased. Eleven of the 15 burn injury fatalities had high levels of alcohol, HCN, or COHb, possibly contributing to an inability to leave a burning vehicle. Faster rescue brought by improved specific education and training of ambulance and rescue services personnel may be of future importance, as may on-scene antidote administration and revised regulations of vehicle flammability.

Mobilisation of emergency services for chemical incidents in Sweden - a multi-agency focus group study.

BACKGROUND: In chemical incidents, infrequent but potentially disastrous, the World Health Organization calls for inter-organizational coordination of actors involved. Multi-organizational studies of chemical response capacities are scarce. We aimed to describe chemical incident experiences and perceptions of Swedish fire and rescue services, emergency medical services, police services, and emergency dispatch services personnel. METHODS: Eight emergency service organizations in two distinct and dissimilar regions in Sweden participated in one organization-specific focus group interview each. The total number of respondents was 25 (7 females and 18 males). A qualitative inductive content analysis was performed. RESULTS: Three types of information processing were derived as emerging during acute-phase chemical incident mobilization: Unspecified (a caller communicating with an emergency medical dispatcher), specified (each emergency service obtaining organization-specific expert information), and aligned (continually updated information from the scene condensed and disseminated back to all parties at the scene). Improvable shortcomings were identified, e.g. randomness (unspecified information processing), inter-organizational reticence (specified information processing), and downprioritizing central information transmission while saving lives (aligned information processing). CONCLUSIONS: The flow of information may be improved by automation, public education, revised dispatcher education, and use of technical resources in the field. Future studies should independently assess these mechanism's degree of impact on mobilisation of emergency services in chemical incidents.

Neck Muscle EMG-Force Relationship and Its Reliability During Isometric Contractions.

BACKGROUND: Susceptible to injury, the neck is subject to scientific investigations, frequently aiming to elucidate possible injury mechanisms via surface electromyography (EMG) by indirectly estimating cervical loads. Accurate estimation requires that the EMG-force relationship is known and that its measurement error is quantified. Hence, this study examined the relationship between EMG and isometric force amplitude of the anterior neck (AN), the upper posterior neck (UPN), and the lower posterior neck (LPN) and then assessed the relationships' test-retest reliability across force-percentiles within and between days. METHODS: EMG and force data were sampled from 18 participants conducting randomly ordered muscle contractions at 5-90% of maximal voluntary force during three trials over 2 days. EMG-force relationships were modeled with general linear mixed-effects regression. Overall fitted lines' between-trial discrepancies were evaluated. Finally, the reliability of participants' fitted regression lines was quantified by an intraclass correlation coefficient (ICC) and the standard error of measurement (SEM). RESULTS: A rectilinear model had the best fit for AN while positively oriented quadratic models had the best fit for UPN and LPN, with mean adjusted conditional coefficients of determination and root mean square errors of 0.97-0.98 and 4-5%, respectively. Overall EMG-force relationships displayed a maximum 6% between-trial discrepancy and over 20% of maximal force, and mean ICC was above 0.79 within day and 0.27-0.61 between days across areas. Corresponding SEM was below 12% both within and between days across areas, excluding UPN between days, for which SEM was higher. CONCLUSIONS: EMG-force relationships were elucidated for three neck areas, and provided models allow inferences to be drawn from EMG to force on a group level. Reliability of EMG-force relationship models was higher within than between days, but typically acceptable for all but the lowest contraction intensities, and enables adjustment for measurement imprecision in future studies.

Decelerations of Parachute Opening Shock in Skydivers.

INTRODUCTION: High prevalence of neck pain among skydivers is related to parachute opening shock (POS) exposure, but few investigations of POS deceleration have been made. Existing data incorporate equipment movements, limiting its representability of skydiver deceleration. This study aims to describe POS decelerations and compare human- with equipment-attached data. METHODS: Wearing two triaxial accelerometers placed on the skydiver (neck-sensor) and equipment (rig-sensor), 20 participants made 2 skydives each. Due to technical issues, data from 35 skydives made by 19 participants were collected. Missing data were replaced using data substitution techniques. Acceleration axes were defined as posterior to anterior (+ax), lateral right (+ay), and caudal to cranial (+az). Deceleration magnitude [amax (G)] and jerks (G · s-1) during POS were analyzed. RESULTS: Two distinct phases related to skydiver positioning and acceleration direction were observed: 1) the x-phase (characterized by -ax, rotating the skydiver); and 2) the z-phase (characterized by +az, skydiver vertically oriented). Compared to the rig-sensor, the neck-sensor yielded lower amax (3.16 G vs. 6.96 G) and jerk (56.3 G · s-1 vs. 149.0 G · s-1) during the x-phase, and lower jerk (27.7 G · s-1 vs. 54.5 G · s-1) during the z-phase. DISCUSSION: The identified phases during POS should be considered in future neck pain preventive strategies. Accelerometer data differed, suggesting human-placed accelerometry to be more valid for measuring human acceleration.Gladh K, Lo Martire R, Äng BO, Lindholm P, Nilsson J, Westman A. Decelerations of parachute opening shock in skydivers. Aerosp Med Hum Perform. 2017; 88(2):121-127.

Free Fall Acrobatics to Reduce Neck Loads During Parachute Opening Shock: Evaluation of an Intervention (ACROPOSE).

INTRODUCTION: Neck pain is a widespread health problem in the skydiver athlete population, epidemiologically linked to repeated exposure to parachute opening shock (POS). During POS, a parachutist is subjected to considerable deceleration forces. This study aims to evaluate the use of preventive free fall acrobatics to reduce the biomechanical load on the neck of parachutists during parachute opening. METHODS AND ANALYSIS: Interventional study with a cross-over, within-subject, repeated measures design. Two consecutive skydives are made on the same day with random ordering of either an 'intervention jump' or a 'control jump'. The intervention jump contains two acrobatic elements prior to main parachute extraction: Reducing parachute deployment airspeed and positioning the human body head high. The primary outcome measure is the magnitude of initial Gx deceleration. All other directions of accelerations will be measured as well, as will magnitudes of multidirectional jerks (rates of changes of accelerations) and lower neck torque. Repeated within group measures analysis of variance will be used to quantify effects, and regression used to test for relationships between the elements of the intervention. ETHICS AND DISSEMINATION: Regional Medical Research Ethics Committee of Stockholm approval 2015/1189-31. The intervention protocol has been systematically prevalidated with an emphasis on participant safety. The study will be conducted in compliance with the Declaration of Helsinki, and its results published in peer-reviewed journals, preferably Open Access, to maximise access for the target athlete population. TRIAL REGISTRATION NUMBER: NCT02625896. Pre-results.

Validation of a free fall acrobatics intervention protocol to reduce neck loads during parachute opening shock.

BACKGROUND: Elevated neck pain prevalence among skydivers is associated with exposure to repeated parachute opening shock (POS). A study is planned to evaluate a preventive free fall acrobatics intervention, but prior assessment of the protocol is necessary given the complex and safety-critical study environment. AIM: To validate an intervention protocol to reduce POS neck loads. METHODS: A protocol was developed based on observational data and theoretical calculations. Six experts rated each component of the protocol on a four-point Likert scale, regarding relevance, simplicity/feasibility and safety, and responded to open-ended questions. Two iterations were made, each followed by consensus panel protocol revisions. The content validity index (CVI) was used to quantify ratings. A measure of universal agreement (CVI/UA) was computed as the proportion of components that achieved a rating ≥3 by all raters. For safety, a high-sensitivity CVI/UA was computed with a rating of no <4 (highest score) as acceptable. RESULTS: CVI/UA for relevance increased from 0.80 in the first assessment to 1.00 in the second; for simplicity from 0.50 to 0.63; and for safety from 0.70 to 1.00. High-sensitivity CVI/UA for safety increased from 0.10 to 0.75. Responses to open-ended questions included safety concerns for free fall stability, altitude awareness and concerns over comprehensibility. CONCLUSIONS: The proposed protocol has been improved in assessed relevance, simplicity and safety, and is considered validated for the start of the empirical trial. To what degree complex interventions should be preceded by open prevalidation is discussed.

Experiences of Injuries and Injury Reporting among Swedish Skydivers.

The objective was to illuminate the experience of injuries and the process of injury reporting within the Swedish skydiving culture. Data contained narrative interviews that were subsequently analyzed with content analysis. Seventeen respondents (22-44 years) were recruited at three skydiving drop zones in Sweden. In the results injury events related to the full phase of a skydive were described. Risk of injury is individually viewed as an integrated element of the recreational activity counterbalanced by its recreational value. The human factor of inadequate judgment such as miscalculation and distraction dominates the descriptions as causes of injuries. Organization and leadership act as facilitators or constrainers for reporting incidents and injuries. On the basis of this study it is interpreted that safety work and incident reporting in Swedish skydiving may be influenced more by local drop zone culture than the national association regulations. Formal and informal hierarchical structures among skydivers seem to decide how skydiving is practiced, rules are enforced, and injuries are reported. We suggest that initial training and continuing education need to be changed from the current top-down to a bottom-up perspective, where the individual skydiver learns to see the positive implications of safety work and injury reporting.

Glucose changes and working memory in individuals with type 1 diabetes during air pressure changes simulating skydiving.

BACKGROUND: Several countries restrict individuals with type 1 diabetes mellitus (T1DM) from skydiving because of concerns over possible alterations in consciousness. To our knowledge, glucose levels and working memory in individuals with T1DM during skydiving have not been assessed earlier. The objective of this study was to investigate changes in glucose levels and working memory in selected subjects with T1DM compared with control subjects without diabetes mellitus (DM) during ambient air pressure changes as those anticipated during standard skydiving. SUBJECTS AND METHODS: Six subjects with T1DM and six controls were included. Using a hypobaric chamber, the ambient air pressure was changed to simulate a standard skydive from 4,000 m (13,000 feet) above mean sea level. The procedure was repeated six times to mimic a day of skydiving activity with a median of 8.7 h/day (5(th), 95(th) percentile: 8.1, 9.8 h). All subjects carried a continuous glucose monitor (CGM). Capillary glucose tests were taken in order to calibrate the CGM. Hemoglobin oxygen saturation, heart rate, and working memory, evaluated through digit span, were monitored regularly. RESULTS: No subject experienced documented symptomatic hypoglycemia with impaired working memory during the simulations. One asymptomatic hypoglycemia episode with a plasma glucose level of <3.9 mmol/L was recorded in a subject with T1DM, with a corresponding CGM trend indicating declining glucose levels. Interstitial glucose levels of <3.9 mmol/L were recorded by CGM in three of the controls during the simulations. There were no significant differences in hemoglobin oxygen saturation, heart rate, or working memory between the T1DM patients and the controls. CONCLUSIONS: This study of interstitial glucose levels and working memory could not show the activity-specific risk factor (i.e., repetitive rapid-onset hypobaric hypoxia exposures) to be a greater safety concern for selected subjects with T1DM compared with subjects without DM during a simulated day of skydiving. Further studies are needed to clarify the suitability of subjects with T1DM to participate in this air sport.

Fatalities in wingsuit BASE jumping.

OBJECTIVE: To analyze fatality data associated with wingsuit use in an international case series of fixed-object sport parachuting (BASE jumping) to identify incident and injury mechanisms and to form a basis for potential prevention measures and future safety recommendations. METHODS: A descriptive epidemiological study was performed of fatal injury events occurring in wingsuit BASE jumping. Fatalities (n = 180) were sequentially analyzed assessing human, equipment, and environmental factors from 1981 to 2011. Main outcome measures included descriptions of typical fatal incident and injury mechanisms. RESULTS: Of the 180 fatal events, 39 (22%) were related to use of wingsuits; 38 (97%) launched from cliffs and 1 (3%) from a building. Of the 39 fatalities, 19 (49%) were caused from cliff strikes, 18 (46%) from ground impact, and 1 (3%) from a building strike. Thirty-eight (97%) of the fatalities were male. During 2002 to 2007 there was a total of 61 BASE jumping deaths, 10 (16%) of which were related to the use of wingsuits, whereas during 2008 to 2011 there was a total 59 fatal events, of which 29 (49%) were related to the use of wingsuits. Seventeen fatalities (39%) were attributed to wingsuit path miscalculation. In the first 8 months of 2013, 17 of 19 (90%) fatalities were wingsuit related. Most fatalities occurred between April and October, reflecting a seasonal increase in activity in the northern hemisphere summer. CONCLUSIONS: Wingsuit-related BASE jump fatalities appear to be increasing as wingsuit BASE jumping increases in popularity. Most fatalities are attributed to cliff or ground impact, and are mostly the result of flying path miscalculation.

Musculoskeletal pain and related risks in skydivers: a population-based survey.

INTRODUCTION: Sport parachuting from aircraft (skydiving) is a major aerial activity in which parachutists are subject to decelerating forces during parachute opening shock (POS), possibly as much as 3-5 G. While traumatic incidents related to POS have been reported, epidemiological data on musculoskeletal pain among skydivers is absent in the literature. The aim was therefore to examine the prevalence of self-rated musculoskeletal pain related to POS in a skydiver population and elicit related risk factors. METHODS: There were 658 Swedish sport skydivers who completed a structured web-based questionnaire (70% response rate; email invitation) validated for use in skydivers. The questionnaire concerned individual and skydiving-related risk indicators, and musculoskeletal pain experiences. Multiple regression analysis was used to estimate the relationship between risk indicators and musculoskeletal pain related to POS. RESULTS: The 12-mo prevalence of musculoskeletal pain related to POS was highest for the neck region, 25% (95% CI = 21.4-28.2). Other upper-body regions were as follows: shoulder 16% thoracic spine 10%, and lower back 18%. A high number of parachute jumps in the last 12 mo, i.e., 30-90 jumps (RR = 1.7, 95% CI = 1.1-2.7), > 90 jumps (RR = 2.1, 95% CI = 1.3-3.4), and a high main parachute wing-loading, i.e., > 1.4 lb/ft2 (RR = 1.7, 95% CI = 1.1-2.6) were independent risk factors. CONCLUSIONS: Neck pain related to POS was common among skydivers. A high number of parachute jumps the last 12 mo and high wing-loading emerged as risk factors, suggesting that highly active skydivers using small canopies may be at risk. Studies on biomechanics under POS are suggested.

Decelerations and muscle responses during parachute opening shock.

INTRODUCTION: Pain in the neck region among skydivers can be related to repeated parachute opening shocks (POS), but empirical data on ramair POS biomechanics is lacking in the literature. The aim of this study was to develop and evaluate a methodology for assessment of multidirectional accelerations and neck muscle activity during parachuting, and to describe preliminary data. METHODS: In an experimental design, four experienced skydivers made two consecutive skydives. Deceleration was recorded with two triaxial accelerometers, one placed on the skydiver's cervicothoracic junction (acc-neck) and the other on the harness (acc-rig). Surface electromyography (EMG) was sampled from four sites bilaterally: anterior-neck, posterior upper and lower neck, and upper shoulder muscles. EMG activity was normalized against a premeasured maximum voluntarily produced electrical signal (MVE). RESULTS: The measuring equipment did not interfere with the parachute jumps. High-quality signals were recorded. The median peak POS deceleration for the acc-neck vs. acc-rig indicated differences (4.0 G vs. 5.1 G), in addition to significant differences emerging for medians of average and maximum onset rates of deceleration (avg: 1.2 G x s(-1) vs. 19.5 G x s(-1); max: 23.0 G x s(-1) vs. 80.0 G x s(-1)). The median of overall muscleactivity was as high as 87% MVE, but no differences in peak activity were found between muscles. Temporal activations of the posterior upper neck occurred less than 50 ms after deceleration initiation, indicating feedforward control of the neck. CONCLUSION: All instruments recorded data of good quality without impeding the skydiving activity. Triaxial accelerometry on the neck vs. the harness yielded dissimilar results, underlining the importance of correct accelerometer placement. Muscle activity was high during POS and neck muscles showed anticipatory tendencies.

Effectiveness of motivational interviewing and physical activity on prescription on leisure exercise time in subjects suffering from mild to moderate hypertension.

BACKGROUND: Physical inactivity is considered to be the strongest individual risk factor for poor health in Sweden. It has been shown that increased physical activity can reduce hypertension and the risk of developing cardiovascular diseases. The objective of the present pilot study was to investigate whether a combination of Motivational Interviewing (MI) and Physical Activity on Prescription (PAP) would increase leisure exercise time and subsequently improve health-related variables. METHODS: This pilot study was of a repeated measures design, with a 15 months intervention in 31 patients with mild to moderate hypertension. Primary outcome parameter was leisure exercise time and secondary outcome parameters were changes in blood pressure, Body Mass Index (BMI), waist circumference, lipid status, glycosylated haemoglobin (HbA1c) and maximal oxygen uptake (VO2 max). Assessments of the outcome parameters were made at baseline and after 3, 9 and 15 months. RESULTS: Leisure exercise time improved significantly from < 60 min/week at baseline to a mean activity level of 300 (± 165) minutes/week at 15 months follow up. Furthermore, statistically significant improvements (p < 0.05) were observed in systolic (-14,5 ± 8.3 mmHg) and diastolic blood pressure (-5,1 ± 5.8 mmHg), heart rate (-4.9 ± 8.7 beats/min, weight (-1.2 ± 3.4 kg) BMI -0.6 ± 1.2 kg/m2), waist circumference (-3.5 ± 4.1 cm) as well as in VO2 max (2.94 ± 3.8 ml/kg and 0.23, ± 0.34 lit/min) upon intervention as compared to baseline. CONCLUSIONS: A 15 month intervention period with MI, in combination with PAP, significantly increased leisure exercise time and improved health-related variables in hypertensive patients. This outcome warrants further research to investigate the efficacy of MI and PAP in the treatment of mild to moderate hypertension.

The SKYNET data: demography and injury reporting in Swedish skydiving.

BACKGROUND: The Swedish Parachute Association (SFF) national registry of skydiving injuries is one of the few trauma databases available for research on sport parachuting. The usefulness of this compulsory reporting system may benefit from a description of its base population and an evaluation of its sensitivity and specificity. METHODS: Cross-sectional analysis based on data collected through a web-based questionnaire (SKYNET), from all persons renewing a Swedish skydiving license 2008 (n=1049). Sensitivity was measured as the proportion of injury events fulfilling the reporting criterion (injury event requiring care of a physician) that were actually reported, by comparing the injury events reported to the SFF during the skydiving seasons 2006 and 2007 with the injury events retrospectively reported to the web-based questionnaire for the same time period. Specificity was measured as the proportion of false positives in relation to the defined reporting criterion for the same time period. Self-stated bone fractures, shoulder dislocations and cruciate ligament injuries were labeled as non-minor injuries. Factors affecting the likelihood of reporting were evaluated using logistic regression. RESULTS: The response rate was 100%. The overall sensitivity of the reporting system 2006/2007 was 0.37 (95% confidence interval (CI) 0.24-0.51). With self-stated non-minor injuries as the target for reporting, the sensitivity was 0.67 (95% CI 0.43-0.85). No significant effect on reporting was found for gender, age, license level, years in the sport, total number of jumps or club affiliation. The specificity was 0.91 (95% CI 0.83-0.95). Descriptive statistics of the Swedish skydiving population show several gender differences. CONCLUSIONS: The low sensitivity will yield false low incidence calculations, but as there is no evidence for differential underreporting, risk comparisons related to the candidate predictor variables appear reasonably valid. The false positive reporting warrants assortment of incoming data and a clarification of the reporting criteria. Attitudes to reporting may be of value to study, to understand the drivers and constraints for achieving a more complete notification of skydiving injuries.

Injuries in Swedish skydiving.

OBJECTIVE: To create a basis for prevention of modern skydiving injuries. DESIGN: Descriptive epidemiological study. SETTING: National total material. PATIENTS: Data on all reported injury events (n = 257) in Swedish skydiving 1999-2003 (total 539,885 jumps) were retrieved from the Swedish Parachute Association. Non-fatally injured skydivers were sent a questionnaire asking for event and injury details (response rate 89%), and supplementary hospital records were retrieved for the most serious injuries (n = 85). Human, equipment and environmental factors were assessed for risk. MAIN OUTCOME MEASUREMENTS: Frequency and severity of injuries. RESULTS: Incidence of non-fatal injury events was 48 per 100,000 jumps. The lower extremities, spine and shoulders were important regions of injury. The most serious injuries were experienced by licensed skydivers, but students in training had a higher injury rate and more often left the sport because of the injury. Of two student-training systems, one had an incidence less than half that of the other. CONCLUSIONS: A basis for prevention was created, showing a potential for reduction of frequency and severity of injuries with training and technical interventions.

Fatalities in Swedish skydiving.

Exact risk patterns in skydiving fatalities are not well known, but incomplete world injury data indicate that many are preventable. A comprehensive national material for Sweden of 37 skydiving fatalities 1964-2003 were reviewed to identify risk factors. In relation to jump volume, the period 1994-2003 had a fatality rate 11 times lower than 1964-1973. Student skydivers had the highest risk of fatal outcome, often caused by instability in freefall leading to unstable parachute activation with subsequent line entanglement, or parachute activation failure. Unintentional water landings also contributed to student fatality, with life jacket malfunctions, neglect to use life jackets, and automatic reserve parachute activation devices activated by water as aggravating factors. One-third of all fatalities had an inflated and operational parachute at some point prior to injury. A drastic worldwide increase in fatal landing incidents with fast wing parachutes during the 1990s did not occur in Sweden. Every fourth fatality caused by rapid deceleration against ground or water survived impact and died during transports or in hospitals. Rescue units and health care providers can improve management of skydiving incidents from knowledge about the incident and injury mechanisms we have described, and the skydiving community can target risk factors in preventive safety work.