Validation of a Portable Blood Gas Analyzer for Use in Challenging Field Conditions at High Altitude

Abstract

BackgroundNovel, portable blood gas analyzers (BGAs) may serve as essential point-of-care tools in remote regions, during air travel or in ambulance services but they have not been extensively validated.Research QuestionWe compared accuracy of a portable BGA to a validated stationary device.MethodsIn healthy individuals and patients with chronic obstructive pulmonary disease participating in clinical field studies at different altitudes, arterial blood samples were obtained at rest and during exercise in a hospital at 760 m and in a high altitude clinic at 3100 m. Paired measurements by a portable BGA (EPOC, Siemens Healthcare) and a stationary BGA (Rapidpoint500, Siemens Healthcare) were performed to compute bias (mean difference) and limits of agreement (95% CI of bias).ResultsOf 105 individuals, 248 arterial blood samples were analyzed, 108 at 760 m, 140 at 3100 m. Ranges of values measured by portable BGA were: pH 7.241−7.473, PaCO2 21.5−52.5 mmHg, and PaO2 45.5−107.1 mmHg. Bias (95% CI) between devices were: pH 0.007 (−0.029 to 0.044), PaCO2 −0.3 mmHg (−4.8 to 4.2), and PaO2 −0.2 mmHg (−9.1 to 4.7). For pH, agreement between devices was improved by the equation to correct pH by portable BGA = −1.37 + pHmeasured × 1.19; bias after correction −0.007 (−0.023 to 0.009). The portable BGA was easily handled and worked reliably.InterpretationAccuracy of blood gas analysis by the portable BGA in comparison to the reference BGA was adequate for clinical use. Because of portability and ease of handling, portable BGA are valuable diagnostic tools for use in everyday practice as well as under challenging field conditions.

Effect of Acute Ketone Monoester Ingestion on Cardiorespiratory Responses to Exercise and the Influence of Blood Acidosis

“…A total of ~2 mL of venous blood was collected in a lithium-heparinized syringe during each draw. The sample first underwent blood-gas analysis by a validated point-of-care analyzer (EPOC; Siemens Healthineers, Ontario, Canada) (23). Next, a drop of whole venous blood was applied to point-of-care analyzer to determine [β-hydroxybutyrate] (β-ketone test strips, Freestyle Precision Neo; Abbott Laboratories, Abbott Park, IL).…”

Validation of Noninvasive Assessment of Pulmonary Gas Exchange in Patients with Chronic Obstructive Pulmonary Disease during Initial Exposure to High Altitude

“…To the best of our knowledge, this research represents the widest validation study of such non-invasive gas exchange assessment method in a homogenous cohort of hypoxemic patients with moderate-to-severe COPD, following a short high-altitude exposure. The main findings indicate the ability of the AGM100 to predict PaO 2 (with an absolute low mean bias of 2 mmHg versus measured PaO 2 with a previously validated point-of-care analyzer [20]) and the satisfying diagnosis predictive performance (Table 4) of this device to diagnose severe resting hypoxemia. Moreover, the AGM100 provides an estimation of the pulmonary gas exchange efficacy through the O 2 deficit.…”

“…Sensitivity analysis: since aBGA point-of-care devices as EPOC may not be considered as accurate as stationary devices, we conducted a sensitivity analysis for PaO 2 and A-aDO 2 agreements, using a corrected value of mPaO 2 computed from the regression equation developed in a previous validation study of the EPOC, conducted in similar field conditions [20].…”

“…PaO 2 , PaCO 2 , and arterial pH were analyzed. The EPOC has been previously validated in a high-altitude environment [20].…”

“…2 , calculated arterial oxygen partial pressure (AGM100); mPaO 2 , measured arterial oxygen partial pressure (EPOC); SpO 2 , pulse oxygen saturation; O 2 deficit, oxygen deficit (AGM100); A-aDO 2 , alveolar-to-arterial oxygen gradient (EPOC); SD, standard deviation; CI, confidence interval; LOA, limits of agreement. a mPaO 2 obtained from the EPOC was corrected using the following equation: PaO 2 corrected = 9.45 + mPaO 2 × 0.9020 .…”