Murdoch University Research Repository

Welcome to the Murdoch University Research Repository

The Murdoch University Research Repository is an open access digital collection of research
created by Murdoch University staff, researchers and postgraduate students.

Learn more

Evaluation of Masimo signal extraction technology pulse oximetry in anaesthetized pregnant sheep

Quinn, C.T., Raisis, A.L. and Musk, G.C. (2013) Evaluation of Masimo signal extraction technology pulse oximetry in anaesthetized pregnant sheep. Veterinary Anaesthesia and Analgesia, 40 (2). pp. 149-156.

Link to Published Version:
*Subscription may be required


Objective Evaluation of the accuracy of Masimo signal extraction technology (SET) pulse oximetry in anaesthetized late gestational pregnant sheep. Study design Prospective experimental study. Animals Seventeen pregnant Merino ewes. Methods Animals included in study were late gestation ewes undergoing general anaesthesia for Caesarean delivery or foetal surgery in a medical research laboratory. Masimo Radical-7 pulse oximetry (SpO2) measurements were compared to co-oximetry (SaO2) measurements from arterial blood gas analyses. The failure rate of the pulse oximeter was calculated. Accuracy was assessed by Bland & Altman's (2007) limits of agreement method. The effect of mean arterial blood pressure (MAP), perfusion index (PI) and haemoglobin (Hb) concentration on accuracy were assessed by regression analysis. Results Forty arterial blood samples paired with SpO2 and blood pressure measurements were obtained. SpO2 ranged from 42 to 99% and SaO2 from 43.7 to 99.9%. MAP ranged from 24 to 82mmHg, PI from 0.1 to 1.56 and Hb concentration from 71 to 114gL-1. Masimo pulse oximetry measurements tended to underestimate oxyhaemoglobin saturation compared to co-oximetry with a bias (mean difference) of -2% and precision (standard deviation of the differences) of 6%. Accuracy appeared to decrease when SpO2 was <75%, however numbers were too small for statistical comparisons. Hb concentration and PI had no significant effect on accuracy, whereas MAP was negatively correlated with SpO2 bias. Conclusions and clinical relevance Masimo SET pulse oximetry can provide reliable and continuous monitoring of arterial oxyhaemoglobin saturation in anaesthetized pregnant sheep during clinically relevant levels of cardiopulmonary dysfunction. Further work is needed to assess pulse oximeter function during extreme hypotension and hypoxaemia.

Item Type: Journal Article
Murdoch Affiliation(s): School of Veterinary and Biomedical Sciences
Publisher: Blackwell Publishing Inc.
Copyright: © 2012 The Authors.
Item Control Page Item Control Page