Oxygen therapy in intensive care

Abstract

Pulse oximetry has high sensitivity but low specificity for detecting hypoxemia. Arterial blood gas analyses are the gold standard for monitoring O2 therapy. Venous blood gas analyses should not be used in this setting. TARGET VALUES OF O2 THERAPY: The target range of acute O2 therapy for ventilated patients and nonventilated patients not at risk of hypercapnia should be between 92% and 96% for oxygen saturation (SpO2) measured by pulse oximetry. Indications for high-dose O2 therapy without a target range in critical care include carbon monoxide poisoning and patients with severe respiratory distress when SpO2 cannot be derived. Hyperoxemia, i.e., SpO2 values above 96%, has not improved survival in randomized trials of predominantly ventilated ICU patients. Under hyperoxemia in nonventilated patients at risk of hypercapnia (e.g., patients with chronic obstructive pulmonary disease), one in three patients is at risk of increasing carbon dioxide. Therefore, a target SpO2 of 88-92% should be aimed for in these patients. O2 TARGET RANGES ON EXTRACORPOREAL PROCEDURES: There are no randomized studies recommending other SpO2 target ranges for patients on extracorporeal procedures. These patients should always be monitored with arterial blood gases-in the case of peripheral VA-ECMO on the right arm and downstream of the oxygenator. HIGH-FLOW OXYGEN THERAPY FOR ACUTE HYPERCAPNIC RESPIRATORY FAILURE: High-flow oxygen therapy (HFNC) was not associated with reduced in-hospital mortality compared with conventional O2 in a meta-analysis of predominantly patients with acute hypoxemia (type I respiratory failure), although intubation rates were reduced. Also, in acute hypercapnic respiratory failure (type II), HFNC with high flow rates is not inferior to noninvasive ventilation (NIV).