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

Abstract

ObjectiveTo determine if non-invasive oxygenation indices, namely peripheral capillary oxygen saturation (SpO2)/fraction of inspired oxygen (FiO2) and partial pressure of alveolar oxygen (PAO2)/FiO2 may be used as effective surrogates for the partial pressure of arterial oxygen (PaO2)/FiO2. Also, to determine the SpO2/FiO2 and PAO2/FiO2 values that correspond to PaO2/FiO2 thresholds for identifying acute respiratory distress syndrome (ARDS) in patients following coronary artery bypass graft (CABG) surgery.MethodsA 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 SPO2, PaO2, PAO2, SaO2, and FiO2. 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.ResultsOne-hundred seventy-five patients were enrolled in the derivation cohort, and 358 in the validation cohort. The SPO2/FiO2 and PAO2/FiO2 ratios could be predicted well from PaO2/FiO2, described by the linear regression models SPO2/FiO2 = 71.149 + 0.8PF and PAO2/FiO2 = 38.098 + 2.312PF, respectively. According to the linear regression equation, a PaO2/FiO2 ratio of 300 equaled an SPO2/FiO2 ratio of 311 (R2 0.857, F 1035.742, < 0.0001) and a PAO2/FiO2 ratio of 732 (R2 0.576, F 234.887, < 0.0001). The SPO2/FiO2 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 PAO2/FiO2 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. SPO2/FiO2 had excellent discrimination ability for mild ARDS (AUC ± SE = 0.92 ± 0.017; 95% CI 0.889 to 0.947) as did PAO2/FiO2 (AUC ± SE = 0.915 ± 0.018; 95% CI 0.881 to0.942).ConclusionsPaO2 and SaO2 correlated in the diagnosis of ARDS, with a PaO2/FiO2 of 300 correlating to an SPO2/ FiO2 of 311 (Sensitivity 90%, Specificity 80%). The SPO2/ FiO2 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.

Clinical and therapeutic outcomes of COVID-19 intensive care units (ICU) patients: a retrospective study in Ghana

“…The Berlin criteria defines ARDS using the physiological P/F ratio of ≤300 which significantly correlates with an S/F ratio value of 311 from a large cohort study by Bashar et al . [ 14 ]. Using this cut off S/F ratio, 50% (10/20) of the MICU patients with COVID pneumonia had ARDS whiles the rest had uncomplicated COVID pneumonia.…”

“…For the pruposes of the study and in the absence of arterial blood gases (ABGs) for objective definition of ARDS, all patients with S/F ratio <311 were defined as having acute respiratory distress syndrome (ARDS) as described earlier by Bashar F et al . 2018 [ 14 ].…”

The POSITIONED Study: Prone Positioning in Nonventilated Coronavirus Disease 2019 Patients—A Retrospective Analysis

“…Secondary outcomes included mortality, time to intubation, and changes in oxygenation as quantified by the peripheral capillary oxygen saturation measured by pulse oximetry to the F io 2 (S/F) ratio. The noninvasive S/F ratio was used as a surrogate for the P/F ratio as the two are reliably correlated in various critical illnesses including ARDS ( 19 – 21 ). S/F ratios were abstracted every 4 hours for the first 48 hours from the time the patient was admitted to the hospital.…”

The effect of aromatherapy with rose and lavender on anxiety, surgical site pain, and extubation time after open‐heart surgery: A double‐center randomized controlled trial

“…CABG is used for the management of 26.79% in North America, 0.72% in Asia, 17.94% in Western Europe, and 18.14% in other parts of the world (Mary, 2017) CVD patients. Also, 60% of open‐heart surgeries (OHSs) in Iran are by CABG surgery (Bashar et al, 2018). Following CABG surgery, the patients are managed in cardiac care unit (CCU) and mechanical ventilation is one of the most common postoperative treatments for all of these patients (Barzanji, Zareiyan, Nezamzadeh, & Mazhari, 2019; Bashar, Vahedian‐Azimi, Farzanegan, et al, 2018).…”