BACKGROUND: Transport of mechanically ventilated patients in a combat zone presents challenges, including conservation of resources. In the battlefield setting, provision of oxygen supplies remains an important issue. Autonomous control of oxygen concentration can allow a reduction in oxygen usage and reduced mission weight. METHODS:Trauma patients requiring ventilation and inspired oxygen concentration (FIO(2)) > 0.40 were evaluated for study. Patients were randomized to consecutive 4-hour periods of closed loop control or standard care. The system for autonomous control consisted of a ventilator, oximeter, and a portable computer. The computer housed the control algorithm and collected data every 5 seconds. The controller goal was to maintain pulse oximetry (SpO(2)) at 94 +/- 2% through discrete changes of 1% to 5% every 30 seconds. Ventilator settings and SpO(2) were recorded every 5 seconds for analysis. RESULTS:Forty-five patients were enrolled in this study. Oxygen saturation was maintained in the 92% to 96% saturation range 33 +/- 36% of the time during clinician control versus 83 +/- 21% during closed loop control. Time spent at the target SpO(2) 92% to 96% was 193.3 +/- 59.18 minutes during closed loop control and 87.08 +/- 87.95 minutes during clinician control (p < 0.001). Hyperoxemia was more frequent during clinician control (144.29 +/- 90.09 minutes) than during closed loop control (38.91 +/- 55.86 minutes; p < 0.001). There were no differences in the number of episodes of SpO(2) < 88%. Oxygen usage was reduced by 32% during closed loop control. CONCLUSION:Closed loop control of FIO(2) offers the opportunity for maximizing oxygen resources, reducing mission weight, and providing targeted normoxemia without increasing risk of hypoxemia in ventilated trauma patients.
RCT Entities:
BACKGROUND: Transport of mechanically ventilated patients in a combat zone presents challenges, including conservation of resources. In the battlefield setting, provision of oxygen supplies remains an important issue. Autonomous control of oxygen concentration can allow a reduction in oxygen usage and reduced mission weight. METHODS:Traumapatients requiring ventilation and inspired oxygen concentration (FIO(2)) > 0.40 were evaluated for study. Patients were randomized to consecutive 4-hour periods of closed loop control or standard care. The system for autonomous control consisted of a ventilator, oximeter, and a portable computer. The computer housed the control algorithm and collected data every 5 seconds. The controller goal was to maintain pulse oximetry (SpO(2)) at 94 +/- 2% through discrete changes of 1% to 5% every 30 seconds. Ventilator settings and SpO(2) were recorded every 5 seconds for analysis. RESULTS: Forty-five patients were enrolled in this study. Oxygen saturation was maintained in the 92% to 96% saturation range 33 +/- 36% of the time during clinician control versus 83 +/- 21% during closed loop control. Time spent at the target SpO(2) 92% to 96% was 193.3 +/- 59.18 minutes during closed loop control and 87.08 +/- 87.95 minutes during clinician control (p < 0.001). Hyperoxemia was more frequent during clinician control (144.29 +/- 90.09 minutes) than during closed loop control (38.91 +/- 55.86 minutes; p < 0.001). There were no differences in the number of episodes of SpO(2) < 88%. Oxygen usage was reduced by 32% during closed loop control. CONCLUSION: Closed loop control of FIO(2) offers the opportunity for maximizing oxygen resources, reducing mission weight, and providing targeted normoxemia without increasing risk of hypoxemia in ventilated traumapatients.
Authors: Philippe Jouvet; Allen Eddington; Valérie Payen; Alice Bordessoule; Guillaume Emeriaud; Ricardo Lopez Gasco; Marc Wysocki Journal: Crit Care Date: 2012-05-16 Impact factor: 9.097