Evaluation of pulse oximetry as a surrogate for PaO₂in awake dogs breathing room air and anesthetized dogs on mechanical ventilation

Abstract

Objective:To evaluate the ability of arterial hemoglobin oxygen saturation measurement via pulse oximetry (SpO 2 ) to serve as a surrogate for PaO 2 in dogs.Design: Two-part study: prospective observational and retrospective components. Setting: University teaching hospital.Animals: Ninety-two dogs breathing room air prospectively enrolled on a convenience basis. Retrospective evaluation of 1,033 paired SpO 2 and PaO 2 measurements from 62 dogs on mechanical ventilation.Interventions: Dogs with concurrent SpO 2 and PaO 2 measured on room air had a data sheet completed with blood gas analysis. SpO 2 , PaO 2 , and FiO 2 values were collected from medical records of dogs on mechanical ventilation. Measurements and Main Results:Predicted PaO 2 was calculated from SpO 2 using the dog oxyhemoglobin dissociation curve. The correlation coefficient between measured and predicted PaO 2 was 0.49 (P < 0.0001) in room air dogs and 0.74 (P < 0.0001) in ventilated dogs. In room air dogs, Bland-Altman analysis between measured minus predicted PaO 2 versus the average showed a mean bias of −6.0 mm Hg (95% limit of agreement, −35 to 23 mm Hg). The correlation coefficient between PaO 2 /FiO 2 and SpO 2 /FiO 2 ratios was 0.76 (P < 0.0001). After combining data sets, receiver operating characteristic curve analysis showed the optimal cutoff value for detecting hypoxemia (PaO 2 < 80 mm Hg) was an SpO 2 of 95%, with sensitivity and specificity of 77.8% and 89.5%, respectively. Using this cutoff, 6.9% of SpO 2 readings failed to detect hypoxemia, whereas 7.2% predicted hypoxemia that was not present. Conclusions:The SpO 2 was not clinically suitable as a surrogate for PaO 2 , though it performed better in mechanically ventilated dogs. As sensitivity for the detection of hypoxemia was poor, pulse oximetry does not appear to be an acceptable screening test. The SpO 2 /FiO 2 ratio may have value for evaluation of anesthetized dogs on supplemental oxygen. Arterial blood gas analysis remains ideal for assessment of oxygenation.

Physiological and Clinical Responses in Pigs in Relation to Plasma Concentrations during Anesthesia with Dexmedetomidine, Tiletamine, Zolazepam, and Butorphanol

“…It should be emphasized that arterial blood gas analysis remains ideal for the assessment of oxygenation and to address the presence of hypoxemia [ 43 , 44 ]. In the present study, arterial blood gas analysis was not performed.…”

Bilateral laryngeal paralysis following a ventral slot surgery in a dog

“…Oxygenation status was initially assessed with pulse oximetry during the respiratory crisis. Despite SpO 2 being associated with a low sensitivity for detection of hypoxaemia, it has reliability and an accuracy of ±2 per cent between saturations of 70 per cent and 100 per cent 30 31. In this case, the use of pulse oximetry was suitable as the patient had a rapid response to oxygen via face mask supplementation (100 per cent SpO 2 achieved).…”

Comparison of CPAP and oxygen therapy for treatment of postoperative hypoxaemia in dogs

“…In a recent study SpO 2 , used in a single determination to estimate PaO 2 in dogs, showed a clinically low sensitivity (Farrell et al . 2019). However, although values of PaO 2 were not available, SpO 2 can still be considered a valid alternative, particularly for evaluating the response to treatment.…”