Oxygen Saturation Measurements in Canine Blood Containing Hemoglobin Glutamer‐200 (Bovine): In Vitro Validation of the NOVA CO‐Oximeter

Abstract

This study was designed to validate in vitro oxygen saturation (SO2) measurements with the NOVA CO-Oximeter (Nova Biomedical Corp, Waltham, Mass, USA) in canine blood containing hemoglobin (Hb) glutamer-200 bovine (Hb-200; Oxyglobin, Biopure, Cambridge, Mass, USA) as a Hb-based oxygen carrier recently introduced into clinical practice. In the first set of experiments, stored blood from 6 mixed-breed canine blood donors was used. Target PO2 levels were reached in aliquots of blood samples by tonometry. Oxygen saturation was then measured with the test device and calculated based on known PO2 values. In the second set of experiments, total oxygen content was directly measured by means of an oxygen-specific electrode in aliquots of fresh whole arterial, venous, and mixed (arterial-venous) blood withdrawn from the same canine blood donors. Hb-200 was added to those blood samples to yield plasma Hb concentrations of 1.62, 3.25, 6.50, and 9.75 g/dL. Based on Hb content and SO2 measured by the NOVA CO-Oximeter in these samples, total oxygen content was also calculated for each sample and compared with measured values. A strong correlation was found between SO2 values measured with the co-oximeter in samples after tonometry, and calculated SO2 based on known PO2. Directly measured total blood O2 content varied by </=5% from values computed based on co-oximeter measurements of Hb content and SO2. These results did not change with different levels of oxygenation of the samples or different plasma Hb-200 concentrations. In conclusion, the NOVA CO-Oximeter is an accurate analyzer for measurement of SO2 after Hb-200 administration to canine blood.

Arterial oxygenation and oxygen delivery after hemoglobin-based oxygen carrier infusion in canine hypovolemic shock: A dose-response study

“…Red blood cell Hb (Hb RBC ) was calculated as Hb total Ϫ Hb Plasma . Arterial oxygen content at baseline was also determined using the equation aO 2 ct ϭ (SaO 2 ϫ 1.36 ϫ Hb) ϩ 0.003 ϫ PaO 2 , where constant 1.36 is the oxygen capacity of 1 g of canine Hb (16) and 0.003 ϫ PaO 2 the O 2 ct in milliliters of 1 dL of plasma. Regression analysis of calculated vs. measured aO 2 ct values revealed excellent correlation (slope 1.001).…”

The HemoCue®, a point of care B-hemoglobin photometer, measures hemoglobin concentrations accurately when mixedin vitro with canine plasma and three hemoglobin-based oxygen carriers (HBOC)

“…These possibly can alter the accuracy of photometric measurements. 4,11,12 Jaeger et al compared the HemoCue to a standard hematology analyzer in the clinical setting and demonstrated "sufficient accuracy to support treatment decisions regarding blood transfusions". 2 The article generated controversy regarding the use of Bland and Altman analysis, 13 which we used to analyze our results.…”

“…However, veterinary use of HBOCs in canine models suggests this may be valid. 11,12 This will require validation in human in vivo models.…”

Evaluation of hematological, chemistry and blood gas values in dogs receiving hemoglobin glutamer‐200

“…These studies were performed by combining measured amounts of HBOC to pooled blood or serum samples and measuring the analytes in question. 8,10,11 No studies have been published to evaluate the ex vivo effects of HBOC on laboratory values following administration, or over time, in dogs. The aim of this study was to determine which laboratory assays of canine blood were altered following intravenous (IV) administration of an HBOC.…”