Reliability of Pulse Oximetry during Progressive Hypoxia, Cardiopulmonary Resuscitation, and Recovery in a Piglet Model of Neonatal Hypoxic Cardiac Arrest

Abstract

Background: Pulse oximetry is widely used in intensive care and emergency conditions to monitor arterial oxygenation and to guide oxygen therapy. Objective: To study the reliability of pulse oximetry in comparison with CO-oximetry in newborn piglets during progressive hypoxia, cardiac arrest, cardiopulmonary resuscitation (CPR), and after return of spontaneous circulation (ROSC). Methods: Thirty-three newborn piglets were exposed to hypoxia until asystole occurred and then resuscitated until ROSC. Arterial oxygen saturation was monitored continuously by pulse oximetry (SpO₂) with one sensor applied to the wrist of the right forelimb (FL) and another to the thigh of the left hind limb (HL). Arterial functional oxygen saturation (SaO₂) was measured at baseline and at predefined intervals during each phase of the experiment. SpO₂ was compared with coinciding SaO₂ values and bias considered whenever the difference (SpO₂ - SaO₂) was beyond ±5%. Results: Bias values were lower at the baseline measurements (-3.7 ± 2.3% in FL and -4.1 ± 3.4% in HL) as well as after ROSC (1.5 ± 4.2% in FL and 0.2 ± 4.6% in HL) with higher precision and accuracy than during other experiment phases. During hypoxia induction, cardiac arrest, and CPR, there was a marked decrease in precision and accuracy as well as an increase in bias up to 43 ± 26 and 56 ± 27% in FL and HL, respectively, over a range of SaO₂ from 13 to 51%. Conclusion: Pulse oximetry showed increased bias and decreased accuracy and precision during marked hypoxemia in a model of neonatal hypoxic cardiac arrest.