Delayed low-dose supplemental oxygen improves survival following phosgene-induced acute lung injury.

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.

Early treatment with nebulised salbutamol worsens physiological measures and does not improve survival following phosgene induced acute lung injury.

OBJECTIVES: To examine the effectiveness of nebulised salbutamol in the treatment of phosgene induced acute lung injury. METHOD: Using previously validated methods, 12 anaesthetised large white pigs were exposed to phosgene (Ct 1978 +/- 8 mg min m(-3)), established on mechanical ventilation and randomised to treatment with either nebulised salbutamol (2.5 mg per dose) or saline control. Treatments were given 1, 5, 9, 13, 17 and 21 hours following phosgene exposure. The animals were followed to 24 hours following phosgene exposure. RESULTS: Salbutamol treatment had no effect on mortality and had a deleterious effect on arterial oxygenation, shunt fraction and heart rate. There was a reduction in the number of neutrophils from 24.0% +/- 4.4 to 12.17% +/- 2.1 (p < 0.05) in bronchoalveolar lavage, with some small decreases in inflammatory mediators in bronchoalveolar lavage but not in plasma. CONCLUSION: Nebulised salbutamol treatment following phosgene induced acute lung injury does not improve survival, and worsens various physiological parameters including arterial oxygen partial pressure and shunt fraction. Salbutamol treatment reduces neutrophil influx into the lung. Its sole use following phosgene exposure is not recommended.

Critical care of military burn casualties at Role 3 facilities.

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.

Anaesthetics.

Anaesthesia, like all other medical specialities continues to advance, with improvements in the agents used and techniques employed in order to minimise adverse effects to the patient. This review examines some of these advances and looks forward to what the future might hold in other areas. As well as purely technical advances, other facets of anaesthetic service provision are reviewed, paying particular attention to how to provide a high quality service within the constraints of current working time legislation and revalidation.