Dose dependent development of severe respiratory failure in an ovine model of smoke inhalation and cutaneous flame burn injury

ImrodKtm: To establish a clinically relevant model of severe respiratory failure in adult sheep with a 40% full-thickness cutaneous born and smoke inhalation injury, we developed a dose dependent model of ARDS with predictable severity. Adult respiratory distress syndrome (ARDS), a common accompaniment to severe burn injury is associated with mortality rates of 50% to 80% The combination of full-thickness (3°) cutaneous flame/burn injury ami smoke inhalation may be synergistic or compounding in the development of ARDS. Currently, no large anima] (sheep) model of smoke inhalation and flame bum injury has been developed to study the pathophysiologicaJ events and evaluate potential treatment of the accompanying severe respiratory allure. Methode Adult Suffolk ewes (n=22,31 to 45 kg) were divided into three groups determined by the mutif of breaths of smoke administered (24,36,48) for a graded inhalation injury ntiKriitg burning cotton-toweling material which was iftiiifPiHril into the tracheostomy with a modified bee smoker at airway temperatures <40°C. AU animals also received a 40 percent third-degree flame burn to the body. After injury, the animals were placed on volume controlled ventilation to achieve PaO]>80mmHg and PaCO2<40mmHg. Arterial blood gases (ABG) and ventilator settings were monitored every 6 hours post-injury for up to 7 days. Resvtts: In the 24 breaths of smoke/40% TBSA burn (24/40) group, PaOyFiOj never reached below 300 and PIP was consistently lower than 14cmHjO with normal ABGs throughout the observation period. With 36/40 (n=7X all animate had PaCVFiOz of <300, and PIP 26cmHbO within 40-48 hours and 30% died during the study period of ARDS. In 48/40 (n=12), all animals developed ARDS in 24-30 hours, but none (0/12) survived the experimental period. At 48 hours, PaOyTiOjwas 733 in 24/40,246 in 36/40, and 179 in 48/40 respectively. is smoke inhalation dose-dependent A combination of 36 breaths of smoke and a 40% cutaneous flame burn injury can induce ARDS with predictable severity within 40-48 hours to allow evaluation of varions treatment modalities of ARDS.