Cellular oxygen utilization in health and sepsis

Abstract

The importance of ‘Airway Breathing Circulation’ in delivering oxygen to the tissues is well established and understood. Within the tissues, the mitochondrion is responsible for the utilization of oxygen in the cell. The molecular dynamics that drive the cellular utilization of oxygen, however, is less well described but has distinct applications to clinical practice, especially in sepsis. This article describes the fate of molecular oxygen as it passes from the airway through the circulation into the cell. Particular focus will be placed on the cellular location where oxygen is ultimately utilized, the mitochondrion. Here, oxygen serves as an electron acceptor in the electron transport chain—analogues to the requirement of air in a combustion engine. This is particularly relevant to multiorgan distress syndrome (MODS) in sepsis, where increasing evidence suggests a central role for mitochondrial dysfunction and, in particular, the mitochondrion’s ability to utilize oxygen effectively.