¿Los gases venosos periféricos pueden reemplazar a los gases arteriales en la evaluación de pacientes críticos?

Arterial blood gas analysis is a routine study for ill patients, and provides a lot of information when it comes to making decisions. For a long time arterial blood gases have been used as reference for these decisions, which are often difficult. Arterial blood gases are often painful and technically demanding, often resulting in damage to the arterial wall, especially when repeated measurements are required. Pulse oximetry is a non-invasive alternative to arterial blood gases, but does not allow assessment of partial pressure of carbon dioxide (pCO2). Taking into account routine sampling in hospitals, and that it is often easier to take a sample of venous blood in which measurements can be made of the pH, pCO2, pO2, and bicarbonate and lactate levels, a review is presented of different studies that compare arterial and venous gases in multiple scenarios and determine the importance of these, as well as if peripheral venous gases could at some point replace the arterial gases, and showing that these are only comparable in the estimates of pH. For the time being, and until larger studies show otherwise, venous gases cannot replace arterial gases in acid-base and oxygenation analysis in critically ill patients.