Critical Care Medicine · 1989 · 311 citations · 0 references
Health ProfessionsPhysiologyCritical Care Respiratory TherapyPulmonary Function TestingVentilationGas ExchangeGas Exchange AssessmentMechanical VentilationPulmonary Function AssessmentRespiratory MonitoringRespiratory PhysiologyAir Exchange PerformanceAirflow MeasurementDirect Oxygen Consumption MeasurementPeak Airway Pressure EvaluationPeak Airway Pressure MonitoringRespirator Performance EvaluationRespiratory Gas Exchange
The new gas exchange monitor was evaluated in laboratory simulations and ICU patients. Laboratory simulations showed mean errors of 2–4 % for CO₂ and 4–27 % for O₂, with FiO₂, airway pressure, and PEEP having little effect and only a slight accuracy drop at the highest minute ventilation, and the device was found accurate for ICU gas exchange measurements. Crit Care Med 1989; 17:1041.
The performance of a new gas exchange monitor was assessed both in laboratory simulation and in ICU patients. Laboratory simulation using N2 and CO2 injections resulted in a mean error of 2 ± 2% in CO2 production (co2) and 4 ± 47c in oxygen consumption (o2) in respirator measurements (n = 55) and in a mean error of 3 ± 2% in co2 and 4 ± 27c in o2 in canopy measurements (n = 25). The mean error in RQ during ethanol burning was 2 ± 2% in respirator measurements (n = 45) and 1 ± 17c in canopy measurements. Fio2 had little effect on the accuracy of co2, whereas the accuracy on high rates of o2 (o2 = 400 ml/min) was reduced, when Fio2 increased: the error ranged from 1 ± 1% to 6 ± 17c, except at o2 400 ml/min during Fio2 0.8, where the error was 16 ± 37c. Neither peak airway pressure (+13 to +63 cm H2O) nor PEEP (0 to +20 cm H2O) had an effect on the accuracy. The highest level of minute ventilation studied (22.5 L/min) reduced the accuracy slightly (mean error of co2 4 ± 1% and o2 7 ± 27c). In patients during controlled mechanical ventilation, increasing Fio2 from 0.4 to 0.6 had no effect on the results. o2 was consistently higher by gas exchange than by the Fick principle: 16 ± 97c during controlled ventilation (n = 20), 21 ± 87c on synchronized intermittent mandatory ventilation (n = 10) and 25 ± 87c during spontaneous breathing. We conclude that the device proved to be accurate for gas exchange measurements in the ICU. (Crit Care Med 1989; 17:1041)