The few ICU studies that have included vasopressor-dependent

AC220 patients have revealed mixed results. Bias was significantly increased in a subset of 13 patients receiving vasoactive drugs compared to 89 patients not receiving the drugs, with biases of 0.70 and -0.11 (p < 0.05), respectively [1]. In another study of 18 ICU patients [6], signal failure occurred in 2 of 9 patients receiving vasoactive Inhibitors,research,lifescience,medical drugs. Our study has limitations that warrant discussion. As we studied a relatively homogenous patient population, our results should not be generalized to non-septic critically ill patients or to those outside the initial ED phase of severe sepsis. The retrospective nature of the trial precluded any reliable assessment of the validity of the pulse oximeter waveform Inhibitors,research,lifescience,medical as the SpO2 was recorded. Moreover, as was the case in other studies of pulse oximeter accuracy [1,7], we did not include a control group, complicating the proportion of bias that can be attributed to severe sepsis. Additionally, we could only report if vasopressors were given in the ED and not specifically if they were given at the time that the specific ABG was drawn. We did not control for all factors that may influence bias. For example, we did

not account for other physiologic variables, such as inspiratory pressure [26] or PaCO2 that may affect bias. Nail polish may also affect SpO2 readings Inhibitors,research,lifescience,medical [27]. The standard of care Inhibitors,research,lifescience,medical at our institution is to place the pulse oximeter probe on a digit without nail polish or if all digits have nail polish to remove it with nail polish remover. As this is not routinely charted, our retrospective study could not audit this practice. Finally, despite being the largest study of pulse oximetry accuracy in sepsis, our sample size may have been insufficient, particularly so in the subset analyses. Conclusion In conclusion, in a group Inhibitors,research,lifescience,medical of ED patients with severe sepsis or septic shock, pulse oximters overestimated

measured SaO2 by a mean of 2.75%. Hypoxemia significantly contributed to pulse oximeter bias Vasopressin Receptor whereas acidosis, hyperlactatemia, decreased Hb level, bacteremia, and the need for vasopressors did not. Clinicians should be aware of the bias and the wide limits of agreement when considering SpO2 readings in the management of patients with severe sepsis and septic shock especially when values are <98%. When SaO2 needs to be determined with a high degree of accuracy in such patients arterial blood gases are recommended. Abbreviations ABG: arterial blood gas; ED: emergency department; FiO2: fraction of inspired oxygen; ICNARC: Intensvice Care National Audit & Research Centre; ICU: intensive care unit; SaO2: arterial hemoglobin saturation; SpO2: pulse oximeter oxygen saturation. Competing interests The authors declare that they have no competing interests.