Oxygenation target in acute respiratory distress syndrome

Abstract

Determining oxygenation targets in acute respiratory distress syndrome (ARDS) remains a challenge. Although oxygenation targets have been used since ARDS was first described, they have not been investigated in detail. However, recent retrospective and prospective trials have evaluated the optimal oxygenation threshold in patients admitted to the general intensive care unit. In view of the lack of prospective data, clinicians continue to rely on data from the few available trials to identify the optimal oxygenation strategy. Assessment of the cost-benefit ratio of the fraction of inspired oxygen (FiO2) to the partial pressure of oxygen in the arterial blood (PaO2) is an additional challenge. A high FiO2 has been found to be responsible for respiratory failure and deaths in numerous animal models. Low and high PaO2 values have also been demonstrated to be potential risk factors in experimental and clinical situations. The findings from this literature review suggest that PaO2 values ranging between 80 mmHg and 90 mmHg are acceptable in patients with ARDS. The costs of rescue maneuvers needed to reach these targets have been discussed. Several recent papers have highlighted the risk of disagreement between arterial oxygen saturation (SaO2) and peripheral oxygen saturation (SpO2) values. In order to avoid discrepancies and hidden hypoxemia, SpO2 readings need to be compared with those of SaO2. Higher SpO2 values may be needed to achieve the recommended PaO2 and SaO2 values.