Facing SpO2 and SaO2 discrepancies in ICU patients: is the perfusion index helpful?

• DOI: 10.1007/s10877-019-00371-3
• Publication Date: 2019-08-07T16:03:27Z
• Authors: Mark Thijssen; Loes Janssen; Jos le Noble; Norbert Foudraine
• Keywords: Pulse Oximetry; Arterial blood; Bland–Altman plot; Oxygenation index; Oxygen Saturation

Peripheral oxygen saturation (SpO2) measured by pulse oximetry is an unreliable surrogate marker for arterial oxygenation (SaO2) in critically ill patients. We hypothesized that a higher perfusion index (PFI) would be associated with better accuracy of SpO2 measurement. retrospectively collected SaO2, SpO2, and PFI data each blood gas (ABG) analysis cohort intensive care unit was categorised as low (PFI < 1.0), intermediate (1.0 ≤ 2.5), or high > 2.5). The correlation between SaO2 studied using Pearson's correlation. Bland–Altman plot used to analyse the agreement SaO2. Furthermore, (SpO2–SaO2) difference assessed. level (dis)agreement calculated three categories separately. Overall, 281 patients 1281 points were analysed. There significant (r = 0.69, p 0.01). revealed mean 0.2% limits ± 6% (SD 2%). low; improved only marginally values. estimating moderate little increasing Thus, additive value clinical decision making limited. Therefore, we advise performing ABG before adjusting fraction inspired (FiO2) settings.