Effect of probe design on accuracy and reliability of pulse oximetry in pediatric patients

Abstract

Study Objective: To determine if the traditional band-wrap disposable pulse oximeter probe is more accurate or reliable for oxygen monitoring in children than the reusable clip-type probe. Design: Prospective, observational clinical study. Setting: Operating room of a large university hospital. Patients: 18 children 11 years of age or younger, who were scheduled for general anesthesia with placement of an intraarterial catheter. Interventions: Pulse oximetry values were obtained using both band and clip probes of three pulse oximeters (Nellcor, Hayward CA; Novametrix, Wallingford, CT; Ohmeda, Boulder, CO) and compared with simultaneous hemoximetry values. Dropout rate (percent of down time) also was recorded for each probe-machine combination. Measurements and Main Results: Data were analyzed using bias and precision and t-test. p < 0.05 is considered significant. Bias (mean SpO 2 − SaO 2) is less than 2% for all probe-machine combinations. The range of error observed between SpO 2 and SaO 2for all data points was greatest using the Nellcor band (27.8%) and least using the Ohmeda band (11.4%). In cyanotic children, the greatest bias and precision were observed with Nellcor band (N = 11, −5.12 ± 9.74) and the best agreement with Novametrix band (N = 17, 0.08 ± 4.21). The difference in bias for any test units above or below the median weight of 13.75 kg did not vary by more than 1%. Dropout rate was minimal for all units in nonbypass situations. After cardiopulmonary bypass, no data dropout was observed with Ohmeda band; observed down time with the other units varied between 34% and 55%. Conclusions: The type of probe selected has little effect on accuracy of pulse oximetry in children. After cardiopulmonary bypass, using the Ohmeda band combination may improve the likelihood of obtaining consistent readings and decreasing down time.