Agreement of SpO2, SaO2 and ScO2 in anesthetized cynomolgus monkeys (Macaca fascicularis)

To assess the agreement between three measurements of arterial oxygen saturation (SpO2, SaO2 and ScO2) in anesthetized cynomolgus monkeys. Prospective study. Eleven mature, male cynomolgus monkeys (Macaca fasicularis). Monkeys were anesthetized with intramuscular ketamine followed by intravenous propofol. The trachea of each was intubated and the lungs ventilated. Arterial oxygen saturation was measured with a Nonin 8500 V pulse oximeter, using a lingual clip on the cheek. Arterial blood samples were taken from an indwelling catheter. Inspired oxygen concentration was varied from 12 to 20%, and 88 paired arterial blood samples and saturation measurements were taken. Arterial oxygen saturation in the blood samples was measured using a cooximeter. The saturation was also calculated from the arterial oxygen tension using the Adair equation. The results were compared using Bland and Altman's method. The pulse oximeter readings were 2.7% higher than that of the cooximeter, with a limit of agreement of −3.9 to 9.3%. The pulse oximeter readings were 1.8% higher than the calculated saturation, with a limit of agreement of −6.5% to 10.1%. The cooximeter readings were 0.9% lower than the calculated saturation, with a limit of agreement of −5.6% to 3.8%. The agreement between SpO2 and other measurements of arterial oxygen saturation in this study is typical for this technique. The bias and limits of agreement are consistent with reports in other species. The Nonin 8500 V is a useful pulse oximeter for clinical use in primates.