New clinically relevant sheep model of severe respiratory failure secondary to combined smoke inhalation/cutaneous flame burn injury.
OBJECTIVE
To develop a predictable, dose-dependent, clinically relevant model of severe respiratory failure associated with a 40% total body surface area, full-thickness (third-degree) cutaneous flame burn and smoke inhalation injury in adult sheep.


METHODS
Model development.


METHODS
Research laboratory.


METHODS
Adult female sheep (n = 22).


METHODS
Animals were divided into three groups, determined by the number of smoke breaths administered (24, 36, 48) for a graded inhalation injury. The smoke was insufflated into a tracheostomy with a modified bee smoker at airway temperatures <40 degrees C. All animals concurrently received a 40% total body surface area (third-degree) cutaneous flame burn to the body (flanks). After injury, the animals were placed on volume-controlled ventilation to achieve PaO2 >60 mm Hg and PaCO2 <40 mm Hg. Arterial blood gases and ventilator settings were monitored every 6 hrs postinjury for up to 7 days.


RESULTS
All animals survived the induction of injury. In the 24 smoke breath/40% total body surface area burn (24/40) group, PaO2/F(IO2) never decreased below 300, and peak inspiratory pressure was consistently <14 cm H2O with normal arterial blood gases throughout the observation period. With 36 smoke breaths/40% total body surface area burn (36/40) (n = 7), all animals had PaO2/F(IO2) of <200 and peak inspiratory pressure of 26 cm H2O within 40-48 hrs, as 30% died during the study period. With 48 smoke breaths/40% total body surface area burn (48/40) (n = 12), all animals developed respiratory distress syndrome (RDS) in 24-30 hrs, but none survived the experimental period.


CONCLUSIONS
Development of RDS by smoke and cutaneous flame bum injury depends on smoke inhalation dose. A combination of 36 breaths of smoke and a 40% total body surface area (third-degree) cutaneous flame burn injury can induce severe RDS (PaO2/F(IO2) <200) within 40-48 hrs to allow evaluation of various treatment modalities of RDS.
Alpard
S K
SK
Department of Surgery, University of Texas Medical Branch and Shriners Burns Institute, Galveston, USA.
Zwischenberger
J B
JB
Tao
W
W
Deyo
D J
DJ
Traber
D L
DL
Bidani
A
A
D000465:Algorithms; D000818:Animals; D001830:Body Surface Area; D002056:Burns / Q000503:physiopathology*; D004195:Disease Models, Animal; D005260:Female; D008168:Lung / Q000503:physiopathology; D010100:Oxygen / Q000097:blood; D011379:Prognosis; D011659:Pulmonary Gas Exchange / Q000502:physiology; D012121:Respiration, Artificial; D012128:Respiratory Distress Syndrome / Q000503:physiopathology; D012131:Respiratory Insufficiency / Q000503:physiopathology*; D012756:Sheep; D015208:Smoke Inhalation Injury / Q000503:physiopathology*
D010100:Oxygen