1995 OPEN FORUM Abstracts
DO TAPE AND REPEATED STERILIZATION AFFECT THE ACCURACY OF DISPOSABLE PULSE OXIMETER PROBES?
Christopher Kramer, Curtis Buck CRNA RRT, David Plevak MD, Darrell Schroeder MS, Jeffrey Ward MEd RRT. Department of Anesthesiology, Division of Respiratory Care and Section of Biostatistics Mayo Clinic and Mayo Foundation, Rochester, Minnesota 55905
INTRODUCTION: Pulse oximetry is an accurate and climically useful method of estimating arterial oxygen saturation. A significant fraction of the total cost of applying this technology results from the use of disposable probes. These economic concerns have encouraged the practice of probe recycling. However, oximeter measurements made after taping and recycling have not been validated by controlled study. We undertook this investigation in order to determine the affect that taping and multiple recycling have on pulse oximeter probe competence.
Methods: An Index® Spo2 simulator (Bio-Tek® Instruments Inc.) was used at settings designed to represent a diversity of clinical circumstances (Table 1). Readings were made using a Nellcor N-180® oximeter with the individual probes attached to the Spo2 simulator. Approximately 15 seconds were allowed before the measurements were taken. In total, 100 new single-patient use Nellcor D-25® probes were utilized. 50 probes had 3M® transparent tape (Cat. 193) applied to their fresh, unused adhesive side. The remaining 50 probes did not have tape applied. Readings were obtained before and after application of the tape in the taped group. Baseline readings were also accomplished in the untaped group. The probes were then put through 20 cycles of our routine sterilization/cleaning procedure. These cycles consist of ethylene-oxide sterilization followed by manual cleaning with Kleen-aseptic® disinfectant. Statistical analysis included the rank sum test, signed rank test, and Fisher's exact test.
Table 1 Simulator Criteria
SettingsSpo2 Pulse Pulse Amplitude
"Weak Pulse"90%95 10%
Results: For all 50 taped probes, baseline readings were the same before and after taping. Baseline measurements at each of the three Spo2 simulator settings showed no significant difference between the taped and untaped groups. At all three settings, and in both the taped and untaped groups, no significant difference was found between baseline readings and those after 20 cycles. At the "normal" and "weak pulse" settings, no significant difference was found between the accuracy of the readings in the taped and untaped groups after 20 cycles. However, at the "tachycardia" setting, a significantly higher percentage of taped vs. untaped probes obtained the same measurement at baseline and after 20 cycles (96% vs. 80%, p=.028).
CONCLUSION: Pulse oximeter probes may be effective in estimating arterial saturation after as many as 20 sterilization/cleaning cycles. The application of this transparent adhesive tape does not appear to affect the accuracy of readings and may actually serve to protect the probe from the potentially damaging effects of recycling. Inaccuracies, if and when they do occur, may be more frequent in a clinical setting of tachycardia when tape as a protective mechanism has not been utilized.