[Monitoring of the oxygen saturation of horses during halothane anesthesia using pulse oximetry in the nasal septum].

The use of pulse oximetry for on-line monitoring of oxygen saturation of arterial blood using a probe on the nasal septum is described in the horse. When compared to the results of blood gas analysis an excellent correlation between the two methods for measuring oxygen saturation is found. Nevertheless a discrepancy between the values for oxygen saturation provided by either method is found. This can lead to misinterpretation of oxygen saturation values generated by the pulse oximeter. The cause of this discrepancy is not clear but differences in measuring principle, presence of dyshemoglobins and differences in absorption characteristics of hemoglobin are to be ruled out as major contributors. Contrary to findings in several other animal species occasionally double counting of pulse frequency by the pulse oximeter is seen.