Comparison of non-invasive to invasive oxygenation ratios for diagnosing acute respiratory distress syndrome following coronary artery bypass graft surgery: a prospective derivation-validation cohort study

• Published in: Journal of cardiothoracic surgery Vol. 13; no. 1; p. 123
• Main Authors: Bashar, Farshid R, Vahedian-Azimi, Amir, Farzanegan, Behrooz, Goharani, Reza, Shojaei, Seyedpouzhia, Hatamian, Sevak, Mosavinasab, Seyed M M, Khoshfetrat, Masoum, Khatir, Mohammad A K, Tomdio, Anna, Miller, Andrew C
• Format: Journal Article
• Language: English
• Published: England BioMed Central Ltd 27.11.2018; BioMed Central; BMC
• Subjects: Acute respiratory distress syndrome; Adult respiratory distress syndrome; Aged; Aged, 80 and over; Alveoli; Anesthesia; Blood; Blood pressure; Capillary pressure; Cardiovascular disease; Cohort analysis; Complications and side effects; Coronary artery; Coronary artery bypass; Coronary Artery Bypass - adverse effects; Coronary artery bypass graft surgery; Coronary vessels; Critical care; Demographic variables; Demographics; Demography; Derivation; Diagnosis; Epidemiology; Female; Heart rate; Heart surgery; Humans; Male; Middle Aged; Mortality; Oximetry - methods; Oxygen; Oxygen - blood; Oxygen content; Oxygenation; Oxygenation indices; Pain; Partial pressure; Patient outcomes; Patients; Phlebotomy; Prospective Studies; Radiographs; Ratio of arterial oxygen partial pressure to fractional inspired oxygen; Ratio of partial pressure of alveolar oxygen to fractional inspired oxygen; Ratio of peripheral capillary oxygen saturation to fractional inspired oxygen; Ratios; Regression analysis; Regression models; Research methodology; Respiratory distress syndrome; Respiratory Distress Syndrome, Adult - blood; Respiratory Distress Syndrome, Adult - etiology; Respiratory therapy; Risk factors; Sensitivity; Severity of Illness Index; Skin; Studies; Surgery; Teaching hospitals; Ventilators; Iran; United States; Acute respiratory distress syndrome; Ratio of arterial oxygen partial pressure to fractional inspired oxygen; Ratio of partial pressure of alveolar oxygen to fractional inspired oxygen; Oxygenation indices; Coronary artery bypass graft surgery; Ratio of peripheral capillary oxygen saturation to fractional inspired oxygen
• ISSN: 1749-8090; 1749-8090
• DOI: 10.1186/s13019-018-0804-8

To determine if non-invasive oxygenation indices, namely peripheral capillary oxygen saturation (S O )/fraction of inspired oxygen (F O ) and partial pressure of alveolar oxygen (P O )/F O may be used as effective surrogates for the partial pressure of arterial oxygen (P O )/F O . Also, to determine the S O /F O and P O /F O values that correspond to P O /F O thresholds for identifying acute respiratory distress syndrome (ARDS) in patients following coronary artery bypass graft (CABG) surgery. A prospective derivation-validation cohort study in the Open-Heart ICU of an academic teaching hospital. Recorded variables included patient demographics, ventilator settings, chest radiograph results, and S O , P O , P O S O , and F O . Linear regression modeling was used to quantify the relationship between indices. Receiver operating characteristic (ROC) curves were used to determine the sensitivity and specificity of the threshold values. One-hundred seventy-five patients were enrolled in the derivation cohort, and 358 in the validation cohort. The S O /F O and P O /F O ratios could be predicted well from P O /F O , described by the linear regression models S O /F O  = 71.149 + 0.8PF and P O /F O  = 38.098 + 2.312PF, respectively. According to the linear regression equation, a P O /F O ratio of 300 equaled an S O /F O ratio of 311 (R 0.857, F 1035.742, < 0.0001) and a P O /F O ratio of 732 (R 0.576, F 234.887, < 0.0001). The S O /F O threshold of 311 had 90% sensitivity, 80% specificity, LR+ 4.50, LR- 0.13, PPV 98, and NPV 42.1 for the diagnosis of mild ARDS. The P O /F O threshold of 732 had 86% sensitivity, 90% specificity, LR+ 8.45, LR- 0.16, PPV 98.9, and NPV 36 for the diagnosis of mild ARDS. S O /F O had excellent discrimination ability for mild ARDS (AUC ± SE = 0.92 ± 0.017; 95% CI 0.889 to 0.947) as did P O /F O (AUC ± SE = 0.915 ± 0.018; 95% CI 0.881 to0.942). P O and S O correlated in the diagnosis of ARDS, with a P O /F O of 300 correlating to an S O / F O of 311 (Sensitivity 90%, Specificity 80%). The S O / F O ratio may allow for early real-time rapid identification of ARDS, while decreasing the cost, phlebotomy, blood loss, pain, skin breaks, and vascular punctures associated with serial arterial blood gas measurements.