Comparison of pao2/fio2 and spo2/fio2 ratios in patients diagnosed with acute respiratory distress syndrome in third-step intensive care unit in terms of morbidity and mortality

Introduction and Purpose: Acute Respiratory Distress Syndrome (ARDS) is an inflammatory condition that can result in life-threatening respiratory failure. Despite the low incidence of detection, ARDS is one of the most important syndromes in intensive care unit (ICU)s, as the length of hospital stay in intensive care units is still very high and mortality is still very high. Since the first definition, there have been disagreements about diagnosis and treatment. Recently updated Berlin criteria were published in 2012 and the first seriousness classification was made in ARDS with PaO2/FiO2 ratio. PaO2/FiO2 ratio, which is used both to determine the severity of ARDS and to determine its severity, requires the removal of arterial blood gas (ABG), an invasive procedure. The SpO2/FiO2 ratio calculated using noninvasively measured oxygen saturation (SpO2) with a pulse oximeter allows the evaluation of ARDS for patients without AKG, including the determination of disease severity instead of PaO2/FiO2 ratio. In this study; It is aimed to compare the PaO2/FiO2 ratio and the SpO2/FiO2 ratio in the classification and prognostic evaluation of patients admitted to the 3rd stage Intensive Care Unit of the Department of Chest Diseases of the Faculty of Medicine of Ege University. Material - Method: Ege University Faculty of Medicine, Chest Disease 3rd Stage ICU's were retrospectively screened for patients who had ARDS according to Berlin criteria between 1 January 2015 and 28 February 2018. The first four days of PaO2/FiO2 and SpO2/ FiO2 ratios, applied treatments (mechanical ventilation, antibiotic, sedation, vasopressor, inotrope, diuretic), hospital infection development, ICU hospital stay and mortality were recorded in demographic data, vital findings from admission, classification with ARDS etiologies . Results: A total of 48 patients (29 males, mean age 59.5±15.9) received ARDS. There were moderate ARDS in 24 (50%), severe ARDS in 18 (37.5%) and mild grade ARDS in 6 (12.5%) patients. In the ARDS classification, correlation between PaO2/FiO2 and SpO2/FiO2 ratios (correlation coefficient R: 0.878) was determined. In the literatüre, it has been observed that the use of cigarette smoking which may affect SpO2 has no effect on the relationship between both classifications. Vasopressor status was found to be related to PaO2/FiO2 and SpO2/FiO2 (p=0.002). SpO2/FiO2 values that can be used in our study in place of PaO2/FiO2 in patients grouped according to Berlin criteria; 125 in the vasopressor areas and 145 for those who did not receive vasopressor instead of 100 in order to separate the heavy ARDS from the middle ones, 225 in the vasopressor areas and 245 for those who did not receive vasopressor instead of 200 in order to separate the middle ARDS from the mild grades. When assessed in terms of mortality; the highest mortality in the class using both PaO2/FiO2 and SpO2/FiO2 was found in the severe ARDS group, but the differences between the two groups were not statistically significant. In the class using only PaO2/FiO2 values, mortality in the severe group was found to be statistically higher than those with vasopressor. Conclusion: In the ARDS classification and prediction of mortality, the non-invasively calculated SpO2/FiO2 can be used instead of the PaO2/FiO2 requiring ABG.