Phosgene is a chemical widely used in the plastics industry and has been used in warfare. It produces a life-threatening pulmonary edema within hours of exposure, to which no specific antidote exists. This study aims to examine the pathophysiological changes seen with low tidal volume ventilation (protective ventilation (PV)) strategies compared to conventional ventilation (CV), in a model of phosgene-induced acute lung injury. Anesthetized pigs were instrumented and exposed to phosgene (concentration x time (Ct), 2,350 mg x min x m(-3)) and then ventilated with intermittent positive pressure ventilation (tidal volume (TV) = 10 ml x kg(-1); positive end expiratory pressure, 3 cm H2O; frequency, 20 breaths x min(-1); fractional concentration of inspired oxygen, 0.24), monitored for 6 hours after exposure, and then randomized into treatment groups: CV, PV (A) or (B) (TV, 8 or 6 ml x kg(-1); positive end expiratory pressure, 8 cm H2O; frequency, 20 or 25 breaths x min(-1); fractional concentration of inspired oxygen, 0.4). Pathophysiological parameters were measured for up to 24 hours. The results show that PV resulted in improved oxygenation, decreased shunt fraction, and mortality, with all animals surviving to 24 hours compared to only three of the CV animals. Microscopy confirmed reduced hemorrhage, neutrophilic infiltration, and intra-alveolar edema.
Phosgene is a chemical widely used in the plastics industry and has been used in warfare. It produces life-threatening pulmonary edema within hours of exposure; no antidote exists. This study examines pathophysiological changes seen following treatment with elevated inspired oxygen concentrations (Fi(O2)), in a model of phosgene-induced acute lung injury. Anesthetized pigs were exposed to phosgene (Ct 2500 mg min m(-3)) and ventilated (intermittent positive pressure ventilation, tidal volume 10 ml kg(-1), positive end-expiratory pressure 3 cm H(2)O, frequency 20 breaths min(-1)). The Fi(O2) was varied: group 1, Fi(O2) 0.30 (228 mm Hg) throughout; group 2, Fi(O2) 0.80 (608 mm Hg) immediately post exposure, to end; group 3, Fi(O2) 0.30 from 30 min post exposure, increased to 0.80 at 6 h post exposure; group 4, Fi(O2) 0.30 from 30 min post exposure, increased to 0.40 (304 mm Hg) at 6 h post exposure. Group 5, Fi(O2) 0.30 from 30 min post exposure, increased to 0.40 at 12 h post exposure. The current results demonstrate that oxygen is beneficial, with improved survival, arterial oxygen saturation, shunt fraction, and reduced lung wet weight to body weight ratio in all treatment groups, and improved arterial oxygen partial pressure in groups 2 and 3, compared to phosgene controls (group 1) animals. The authors recommend that treatment of phosgene-induced acute lung injury with inspired oxygen is delayed until signs or symptoms of hypoxia are present or arterial blood oxygenation falls. The lowest concentration of oxygen that maintains normal arterial oxygen saturation and absence of clinical signs of hypoxia is recommended.
The Defence Medical Services are now in an established period of contingency operations. In 2008, the Royal College of Anaesthetists approved a Military Anaesthesia Higher Training Module which could be easily achieved by deploying to the field hospital in Camp Bastion, Afghanistan, for two months under the supervision of a consultant anaesthetist. This opportunity no longer exists but the need to assure quality training and to demonstrate military skill sets is still essential. This article discusses the revised Military Higher Module and how it will be implemented in the future either during deployment or during times of peace.
Although recent studies have shown that the timing of volume replacement deserves careful consideration (56), which fluid to use is less clear, with the perennial debate of crystalloid v colloid and now colloid v colloid still unresolved. This review has examined three sugar solutions, two colloids and one crystalloid. In general, all three agents are unhelpful in the immediate resuscitation of hypovolaemic trauma by virtue of a combination of pathophysiology and side effects. Dextran solutions and mannitol are useful in specific situations.
Burn casualties will inevitably occur in the military environment during both conflict and peacetime. The number and type of casualties will vary on the nature of warfare and the type of troops deployed. New preventative measures have decreased the number and severity of burns found on the battlefield however with new weapon systems casualties suffering from thermal injuries are still to be expected in modern warfare. Over the last 4 decades great advances have been made in the treatment of thermal injuries. These advances are reviewed here with emphasis on those that can be accomplished in the Role 3 facility by non-specialist clinicians. It is beyond the scope of this review to produce didactic treatment protocols but it is hoped that in the near future Clinical Guidelines for Operations will soon reflect these. Where advances have occurred that can not be mirrored in the field hospital early evacuation to specialist facilities back at Role 4 facilities should be a priority.
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