Association between air temperature and unintentional drowning risk in the United Kingdom 2012-2019: A nationwide case-crossover study.

OBJECTIVE: Drowning is a leading cause of death. The World Health Organization (WHO) and United Nations (UN) emphasise the need for population-level data-driven approaches to examine risk factors to improve water safety policies. Weather conditions, have the potential to influence drowning risk behaviours as people are more likely to spend time around water and/or undertake risky activities in aquatic spaces as a behavioural thermoregulatory response (e.g., seeking coolth). METHODS: A case-crossover approach assessed associations between changes in daily maximum air temperature (data from the nearest weather station to each drowning event) and unintentional drowning risk using anonymous data from the validated UK Water Incident Database 2012-2019 (1945 unintentional deaths, 82% male). Control days were selected using a unidirectional time-stratified approach, whereby seven and 14 days before the hazard day were used as the controls. RESULTS: Mean maximum air temperature on case and control days was 15.36 °C and 14.80 °C, respectively. A 1 °C increase in air temperature was associated with a 7.2% increase in unintentional drowning risk. This relationship existed for males only. Drowning risk was elevated on days where air temperature reached 15-19.9 °C (Odds Ratio; OR: 1.75), 20-24.9 °C (OR: 1.87), and ≥ 25 °C (OR: 4.67), compared with days <10 °C. The greatest elevations in risk appeared to be amongst males and when alcohol intoxication was suspected. Precipitation showed no significant association with unintentional drowning risk. CONCLUSIONS: Identifying such relationships highlights the value of considering weather conditions when evaluating environmental risk factors for drowning, and may inform water safety policy and allocating resources to prevention and rescue.

Prevention and Treatment of Nonfreezing Cold Injuries and Warm Water Immersion Tissue Injuries: Supplement to Wilderness Medical Society Clinical Practice Guidelines for the Prevention and Treatment of Frostbite.

We convened an expert panel to develop evidence-based guidelines for the evaluation, treatment, and prevention of nonfreezing cold injuries (NFCIs; trench foot and immersion foot) and warm water immersion injuries (warm water immersion foot and tropical immersion foot) in prehospital and hospital settings. The panel graded the recommendations based on the quality of supporting evidence and the balance between benefits and risks/burdens according to the criteria published by the American College of Chest Physicians. Treatment is more difficult with NFCIs than with warm water immersion injuries. In contrast to warm water immersion injuries that usually resolve without sequelae, NFCIs may cause prolonged debilitating symptoms, including neuropathic pain and cold sensitivity.

Quantifying Risk in Air Sports: Flying Activity and Incident Rates in Paragliding.

INTRODUCTION: The volume, nature, and risks of paragliding are poorly quantified. More comprehensive understanding, including incident rates allowing comparison to similar disciplines, will help direct and appraise safety interventions. METHODS: Paraglider pilots were surveyed regarding experience, incidents, recordkeeping, and risk perception. The survey could not capture those who had left the sport or died, so a subset of responses from UK pilots was compared to records from an incident database. RESULTS: There were 1788 (25%) responses from 7262 surveyed. Respondents flew a total of 87,909 h in 96,042 flights during 2019. Local flying was most frequent (n=37,680 flights, 39%) but a higher proportion of hours were spent flying cross-country (n=33,933 h, 39%). The remainder were spent in competition, hike and fly, tandem, aerobatic, or instructional flight. Flying incidents led to 103 (6%) respondents seeking medical attention, attending hospital, or missing a day of work in 2019. Near misses were reported by 423 (26%) pilots. Asymmetry and rotational forces typically led to incidents, and limb and back injuries resulted. Pilots frequently failed to throw their reserve parachutes. Only 3 (0.6%) incidents involved equipment failure, with the remainder attributed to control or decision errors. Incident rates of paragliding were estimated as 1.4 (1.1-1.9) deaths and 20 (18-27) serious injuries per 100,000 flights, approximately twice as risky as general aviation and skydiving. CONCLUSIONS: Incidents usually resulted from pilot error (control and decision), rather than equipment failure. Future safety interventions should focus on improving glider control skills and encouraging reserve parachute deployment.

Thirst-guided participant-controlled intravenous fluid rehydration: a single blind, randomised crossover study.

BACKGROUND: Dehydration is common in hospitals and is associated with increased mortality and morbidity. Clinical assessment and diagnostic measures of dehydration are unreliable. We sought to investigate the novel concept that individuals might control their own intravenous rehydration, guided by thirst. METHODS: We performed a single-blind, counterbalanced, randomised cross-over trial. Ten healthy male volunteers of mean age 26 (standard deviation [sd] 10.5) yr were dehydrated by 3-5% of their baseline body mass via exercising in the heat (35°C, 60% humidity). This was followed by a 4 h participant-controlled intravenous rehydration: individuals triggered up to six fluid boluses (4% dextrose in 0.18% sodium chloride) per hour in response to thirst. Participants undertook two blinded rehydration protocols which differed only by bolus volume: 50 ml (low volume [LV]) or 200 ml (high volume [HV]). Each hour during the rehydration phase, plasma osmolality (pOsm) was measured and thirst score recorded. Nude body mass was measured at baseline, after dehydration, and after the rehydration phase. RESULTS: In both conditions, the mean dehydration-related body mass loss was 3.9%. Thirst score was strongly associated with pOsm (within-subject r=0.74) and demand for fluid decreased as pOsm corrected. In the HV condition, participants rapidly rehydrated themselves (mean fluid delivered 3060 vs 981 ml in the LV condition) to body mass and pOsm no different to their euhydrated state. CONCLUSION: Healthy individuals appear able to rely on thirst to manage intravenous fluid intake. Future work must now focus on whether patient-controlled intravenous fluids could represent a paradigm shift in the management of hydration in the clinical setting. CLINICAL TRIAL REGISTRATION: NCT03932890.

How cold is too cold? Establishing the minimum water temperature limits for marathon swim racing.

OBJECTIVES: To provide a rationale for minimum water temperature rules for elite and subelite marathon swim racing and highlight factors that make individuals vulnerable to excessive cooling during open water swimming. METHODS: 12 lean competitive swimmers swam for up to 2 hours, three times in different water temperatures between 14°C and 20°C, wearing standard swimming costumes and hats. Rectal temperature (Tre), oxygen consumption, perception of cold and performance were measured. RESULTS: In 16°C, half the swimmers did not complete a 2-hour swim; four became (or were predicted to become) hypothermic within 2 hours. In 18°C, three-quarters completed the swim; three became (or were predicted to become) hypothermic. In 20°C, one swimmer was predicted to become hypothermic in under 2 hours. The mean linear rate of fall of Tre was greater in 16°C (-1.57°C/hour) than 18°C (-1.07°C/hour) (p=0.03). There was no change in swimming performance during the swims or between conditions. Most of the cooling rate could be explained by metabolic heat production and morphology for both 16°C (R2=0.94, p<0.01) and 18°C (R2=0.82, p<0.01) conditions. No relationship was observed between Tre and perception of thermal sensation (r=0.25, p=0.13), and there was a weak correlation between Tre and thermal comfort (r=0.32, p=0.04). CONCLUSION: We recommend that 16°C and 18°C water are too cold for elite marathon swim racing. FédérationInternationale de Natation rules were changed in 2017 to make wetsuits compulsory below 18°C and optional below 20°C.

Scientific rationale for changing lower water temperature limits for triathlon racing to 12°C with wetsuits and 16°C without wetsuits.

OBJECTIVES: To provide a scientific rationale for lower water temperature and wetsuit rules for elite and subelite triathletes. METHODS: 11 lean, competitive triathletes completed a 20 min flume swim, technical transition including bike control and psychomotor testing and a cycle across five different wetsuit and water temperature conditions: with wetsuit: 10°C, 12°C and 14°C; without wetsuit (skins): 14°C and 16°C. Deep body (rectal) temperature (Tre), psychomotor performance and the ability to complete a technical bike course after the swim were measured, as well as swimming and cycling performance. RESULTS: In skins conditions, only 4 out of 11 athletes could complete the condition in 14°C water, with two becoming hypothermic (Tre<35°C) after a 20 min swim. All 11 athletes completed the condition in 16°C. Tre fell further following 14°C (mean 1.12°C) than 16°C (mean 0.59°C) skins swim (p=0.01). In wetsuit conditions, cold shock prevented most athletes (4 out of 7) from completing the swim in 10°C. In 12°C and 14°C almost all athletes completed the condition (17 out of 18). There was no difference in temperature or performance variables between conditions following wetsuit swims at 12°C and 14°C. CONCLUSION: The minimum recommended water temperature for racing is 12°C in wetsuits and 16°C without wetsuits. International Triathlon Union rules for racing were changed accordingly (January 2017).

Physiology Of Drowning: A Review.

Drowning physiology relates to two different events: immersion (upper airway above water) and submersion (upper airway under water). Immersion involves integrated cardiorespiratory responses to skin and deep body temperature, including cold shock, physical incapacitation, and hypovolemia, as precursors of collapse and submersion. The physiology of submersion includes fear of drowning, diving response, autonomic conflict, upper airway reflexes, water aspiration and swallowing, emesis, and electrolyte disorders. Submersion outcome is determined by cardiac, pulmonary, and neurological injury. Knowledge of drowning physiology is scarce. Better understanding may identify methods to improve survival, particularly related to hot-water immersion, cold shock, cold-induced physical incapacitation, and fear of drowning.

Sublingual glyceryl trinitrate and the peripheral thermal responses in normal and cold-sensitive individuals.

Non-freezing cold injury (NFCI) is a prevalent, but largely undiagnosed and poorly understood syndrome afflicting many who, as part of their work or leisure, expose their extremities to cold temperatures. The long term sequelae of NFCI are hyperhidrosis, cold-sensitivity and pain; these can last a lifetime. We tested the hypothesis that, in comparison with a placebo, sublingual glyceryl trinitrate (GTN) would increase the peripheral microcirculation during and after a mild cold challenge of individuals who had not been diagnosed with NFCI, but were cold-sensitive. Naive participants were categorised into two cohort groups: control (n=7) or cold-sensitive (n=6). All participants undertook a standardised two minute cold exposure of their right foot while toe skin temperature (Tsk; infra-red thermograms) and blood flow (toe pad laser Doppler) were measured. GTN increased the rate of rewarming and absolute Tsk of the coldest toe after the cold challenge in cold-sensitive individuals. GTN also increased the blood flow in the great toe during rewarming in some cold-sensitive individuals. We accept our hypothesis and suggest that the impairment in the vasodilatory response seen in individuals with cold-sensitivity can be overcome by the use of GTN, an endothelial-independent NO donor, and thereby improve the rewarming of cooled peripheral tissues.

Quantifying the essential tasks of offshore wind technicians.

BACKGROUND: Offshore wind technicians (WTs) have been identified as having an occupation with varying physical demands. Therefore, in order to assess WTs capability to undertake the job, there was a need to identify and quantify the physical requirements of the essential tasks. OBJECTIVE: To establish the essential tasks and quantify the associated minimum physical demands of being an offshore WT. METHODS: Wind Farm organisations (n = 10) across five countries, undertook a multi-modal observational approach comprising of semi-structured interviews (n = 45), focus groups (n = 14), survey (n = 167). In addition, observations, objective measurements, video footage and standard operating procedures were reviewed. A service campaign was broken down into component tasks, and analysed in terms of technical specifications, e.g. equipment, frequency, duration, rest breaks, clothing ensembles, and the methods of best practice for undertaking each of the tasks. Task descriptions were produced and minimum performance standards recommended. RESULTS: The job tasks associated with WTs can be broken down into two categories and five areas of work (Essential infrequent = casualty evacuation and prolonged ladder climbing; Essential frequent = short ladder climbs, manual handling and working in restricted spaces). CONCLUSIONS: The results presented constitute work carried out in Phases 1 and 2 of a three phased work programme to establish a physical employment standard required by WTs working in offshore wind. These findings will underpin the development of a minimum performance standard for the global offshore wind industry.