Supplemental oxygen impairs detection of hypoventilation by pulse oximetry.

Study Objective: This two-part study was designed to determine the effect of supplemental oxygen on the detection of hypoventilation, evidenced by a decline in oxygen saturation (Spo(2)) with pulse oximetry.

Design: Phase 1 was a prospective, patient-controlled, clinical trial. Phase 2 was a prospective, randomized, clinical trial.

Chest wall disruption with and without acute lung injury: effects of continuous positive airway pressure therapy on ventilation and perfusion relationships.

Objective: We investigated the evolution of lung injury in an animal model with multiple rib fractures, both with and without acute lung injury, and the influence of spontaneous breathing with continuous positive airway pressure (CPAP) therapy on the relative distributions of alveolar ventilation ([OV0312]a) and perfusion ([OV0422]).

Design: Prospective, randomized laboratory investigation using an established porcine model with instrumentation for measurement of ventilation/perfusion distribution, pulmonary mechanics and gas exchange, and cardiovascular variables.

Setting: University experimental research laboratory.