Evaluation of a pulse oximeter in the prehospital setting.

Paramedics field-tested a portable, battery-powered pulse oximeter to determine its applicability and usefulness as an adjunct to prehospital care. The pulse oximeter was attached to 62 consecutive patients who met local criteria for mandatory advanced life support base hospital contact. Arterial hemoglobin saturation (SaO2) levels and changes over time were documented by the pulse oximeter's integral printer and prehospital care reports prepared by paramedics. The pulse oximeter performed reliably in 60 patients (96.7%) by providing continuous SaO2 levels. Fifteen patients (24.2%) had saturations below 91%, and the pulse oximeter detected two (3.2%) otherwise undetected saturations below 80%. In each case, field intervention improved saturation. Pulse oximetry quantifies SaO2 changes correlated with many prehospital interventions: medications, suctioning, precarious gurney transport, oxygen therapy, and ventilatory assistance. The pulse oximeter performs reliably in the field and can be invaluable as an adjunct to patient care. Further prehospital studies are needed to evaluate specific field treatments and techniques, to assess the pulse oximeter's effect on morbidity and mortality, and to analyze the determination of severe hypoxemia in the field.