Invasive And Non-invasive Assessment Of Arterial Blood Oxygen Saturation In Patients With Continuous Flow LVADs: Is There A Correlation?

Abstract

<h3>Background</h3> Patients with continuous flow left ventricular assist devices (CF-LVAD) typically have a narrow pulse pressure. This may pose a challenge for transcutaneous automated pulse oximeter devices to accurately measure arterial blood saturation. This study aimed to assess their accuracy in a CF-LVAD population by comparing pulse oximetry readings to invasive arterial blood gas (ABG) measurements. <h3>Methods</h3> A total of eighteen patients with a CF-LVAD were identified using chart review at the University of Minnesota and Minneapolis Heart Institute. All, except one patient were implanted with a HeartMate III device (Abbott Laboratories, Minneapolis, MN). Non-invasively assessed oxygen saturation was compared to simultaneously obtained arterial blood oxygen saturation. Two patients were receiving mechanical ventilation, one received BiPAP support, and 15 patients were either breathing room air or receiving supplemental oxygen by nasal cannula. <h3>Results</h3> A non-invasive pulse oximeter read was obtained on every patient. There was a moderate correlation between the invasively and non-invasively obtained oxygen saturation values as shown in Figure 1 (R²=0.624). Waveform quality, as assessed by the treating physician, qualified as good or acceptable in 16 cases and as poor for 2 patients. Data points for these 2 patients are marked in red in Figure 1. <h3>Conclusion</h3> Despite a narrow pulse pressure in patients with CF-LVAD, non-invasive pulse oximetry provided a reliable assessment of arterial blood saturation when compared to the gold standard ABG measurement. This finding presents an opportunity to conduct future studies in this patient population in which continuous monitoring of oxygen saturation may be necessary, such as evaluation for obstructive sleep apnea.