The performance of six pulse oximeters in the environment of neuronavigation

Although the use of pulse oximeters may be regarded a standard of care for monitoring anesthesia procedures, these monitors may be susceptible to various kinds of disturbances. Recently, it was suggested that neuronavigation equipment may interfere with pulse oximeter accuracy. In this study, we evaluated the effect of a neurosurgical image guidance system on the performance of six different pulse oximeters. Two simple shielding methods were evaluated.

Twenty healthy, adult, nonsmoking volunteers were equipped with six different pulse oximeters on both hands. Baseline values for heart rate, arterial oxygen saturation, and signal quality were assessed. After activation of the Brain Lab VectorVision Neuronavigation System, the effects on signal quality and saturation recognition were evaluated. Measurements were repeated using two different shielding techniques, a cotton blanket and aluminum sheets.

Activation of the image guidance system resulted in a significant disturbance of signal quality and saturation detection, which was partially reversible by both shielding techniques. Significant differences were noted among the six brands of pulse oximeters for signal quality (P < 0.001) and saturation recognition (P < 0.001), and for the response to shielding methods (P < 0.001). Coverage of the probes with aluminum foil resulted an in undisturbed saturation recognition in all subjects with almost all monitors.

Infrared pulse waves from neurosurgical navigation equipment may interfere with pulse oximeter measurements. Shielding the probe with aluminum foil sufficiently eliminated the infrared interference.