Closed-loop ventilation and oxygenation with decision support fluid resuscitation to treat major burn injury with smoke induced acute respiratory distress syndrome.

Abstract

Introduction: The understanding of the interaction of closed-loop control of ventilation and oxygenation, specifically fraction of inspired oxygen (FiO2) and positive end-expiratory pressure (PEEP), and fluid resuscitation after burn injury and acute lung injury from smoke inhalation is limited. We compared the effectiveness of FiO2, PEEP, and ventilation adjusted automatically using adaptive support ventilation (ASV) and decision support fluid resuscitation based on urine output in a clinically relevant conscious ovine model of lung injury secondary to combined smoke inhalation and major burn injury.

Methods: Sheep were subjected to burn and smoke inhalation injury under deep anesthesia and analgesia. After injury, sheep were randomly allocated to two groups. 1) Closed-loop group: automated mechanical ventilation (ASV), oxygen FiO2 and PEEP (n = 9); and 2) Control group: mechanically ventilated with standard ASV mode (n = 8). FiO2, PEEP, and the percentage of the minute volume (%MV) were automatically adjusted in group 1, whereas PEEP was held at 5 cmH2O, and FiO2 and %MV were manually adjusted in group 2. Decision support fluid resuscitation was guided based on urine output. Cardiopulmonary hemodynamics were monitored for 48 h.

Results: There were no differences in body weight and the severity of smoke injury between the two groups. The Closed-loop group resulted in significantly higher PEEP, %MV, static lung compliance, and survival rate; the driving pressure was significantly lower compared to the Control group. In the Closed-loop group, the net fluid balance at 48 h was significantly greater than in the Control group.

Conclusion: Closed-loop ventilation and oxygenation with decision support fluid resuscitation improve lung mechanics and survival in sheep with combined burn and smoke inhalation. There were no negative interactions observed between automated PEEP control and fluid management.