Changing perspectives in the assessment of oxygenation.

Changing the perspective of clinical assessment to cellular oxygenation assessment will be a trend in the 1990s, particularly with the development of new technologies. New technologies such as MRI and PET scanning will increase clinicians' ability to assess cellular dysfunction and oxygenation disturbances. Because of improved technology, the focus in assessing oxygenation of the critically ill also will change. Critical care clinicians must accurately identify whether arterial or cellular oxygenation is being assessed. Arterial oxygenation problems are usually a reflection of a loss of hemoglobin or deteriorating lung function (through increased intrapulmonary shunting). Cellular oxygenation problems are more related to the relationship between oxygen delivery and cellular utilization of oxygen. In most critical care situations, cellular oxygenation is the aspect of oxygenation that is of most interest. The more familiar the clinician is with the role oxygen plays in cellular metabolism, the more meaningful the oxygenation assessment becomes. Common nursing techniques for the assessment of oxygenation (eg, physical assessment, blood gases and pulse oximetry) still have a place, but their limited accuracy must be kept in perspective when assessing cellular oxygenation.