We assessed the performance of the ratio of peripheral arterial oxygen saturation to the inspired fraction of oxygen (SpO 2 /FiO 2) to predict the ratio of partial pressure arterial oxygen to the fraction of inspired oxygen (PaO 2 /FiO 2) among patients admitted to our emergency department (ED) during the SARS-CoV-2 outbreak. Methods: We retrospectively studied patients admitted to an academic-level ED in France who were undergoing a joint measurement of SpO 2 and arterial blood gas. We compared SpO 2 with SaO 2 and evaluated performance of the SpO 2 /FiO 2 ratio for the prediction of 300 and 400 mmHg PaO 2 /FiO 2 cutoff values in COVID-19 positive and negative subgroups using receiver-operating characteristic (ROC) curves. Results: During the study period from February to April 2020, a total of 430 arterial samples were analyzed and collected from 395 patients. The area under the ROC curves of the SpO 2 /FiO 2 ratio was 0.918 (CI 95% 0.885-0.950) and 0.901 (CI 95% 0.872-0.930) for PaO 2 /FiO 2 thresholds of 300 and 400 mmHg, respectively. The positive predictive value (PPV) of an SpO 2 /FiO 2 threshold of 350 for PaO 2 /FiO 2 inferior to 300 mmHg was 0.88 (CI95% 0.84-0.91), whereas the negative predictive value (NPV) of the SpO 2 /FiO 2 threshold of 470 for PaO 2 /FiO 2 inferior to 400 mmHg was 0.89 (CI95% 0.75-0.96). No significant differences were found between the subgroups. Conclusions: The SpO 2 /FiO 2 ratio may be a reliable tool for hypoxemia screening among patients admitted to the ED, particularly during the SARS-CoV-2 outbreak.
Patients scheduled for vascular surgery are considered at risk for perioperative cardiac complications. Choice of anesthetic in such patients is guided by a desire not to adversely affect myocardial function. On the basis of data from laboratory studies, thoracic epidural anesthesia (TEA) has been advocated to prevent myocardial ischemia. The aim of this study was to assess whether TEA combined with general anesthesia has any effect on segmental wall motion (SWM) monitored by transesophageal echocardiography in these patients. Patients received alfentanil, midazolam, vecuronium, and 50% N2O in oxygen, and ventilation was controlled after orotracheal intubation; 12.5 mL of 2% lidocaine HCl was injected through an epidural catheter placed at T6-7 or T7-8. Hemodynamic measurements and transesophageal echocardiographic recordings were obtained before and 10, 20, 30, 40, and 60 min after lidocaine injection. Segmental wall motion was graded a posteriori by two independent experts on a predetermined scale (from 1 = normal to 5 = dyskinesia). A decrease greater than or equal to 2 grades was considered an SWM abnormality indicative of ischemia. Thoracic epidural anesthesia induced a decrease in systemic arterial blood pressure, heart rate, and cardiac index. The SWM score decreased slightly from 1.34 +/- 0.68 to 1.27 +/- 0.64 (mean +/- SD) (at 10 and 20 min, respectively) (P less than 0.05). Patients were a posteriori analyzed according to whether they had documented coronary artery disease or not. The SWM score before TEA was significantly higher in patients with documented coronary artery disease (1.51 +/- 0.88 vs 1.17 +/- 0.51, respectively; P less than 0.05) and did not change significantly after TEA.(ABSTRACT TRUNCATED AT 250 WORDS)
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