Pulse Oximetry Readings and Hourly Variation in Oximetry Readings With CHD

Congenital heart disease is a relatively common disease seen in 8/1,000 live births. Many of these diseases are associated with hypoxemia. Hypoxemia results from the mixing of pulmonary and systemic blood or from the mixing of parallel circulations as seen in transposition of the great vessels. Pulse oximetry can be used to measure hypoxemia. Pulse oximetry estimates oxygen saturation by measuring absorption of light in human tissue beds. The amount of light absorption varies depending on the amount of deoxygenated blood in the tissue measured. Measuring the changes in light absorption allows for an estimation of arterial oxygen saturation and therefore the amount of hypoxemia. Most manufacturers claim a confidence interval of 4% for their oximeters. There have been a few studies recently describing the presenting pulse oximetry of known congenital heart disease. However, these were small studies with a small sample size of patients. Moreover, there is no literature describing the hourly variation in pulse oximetry among know congenital heart disease patients.

We hypothesize that there is a low presenting pulse oximetry in patients with congenital heart disease and that there will be no significant variation in the hourly variation in oximetry readings in these patients.

This is a retrospective chart review examining the presenting pulse oximetry of patients with known cyanotic heart lesions. The treatment group will be untreated patients with known lesions. All charts of children presenting to Sibley Heart Center with known cyanotic heart lesions from January 1, 2004 to December 31, 2004 will be reviewed.

The aim of the study is to describe the presenting pulse oximetry reading in patients who have a known lesion which will cause them to have a low oximetry reading. The following information will be collected from the charts:

• Presenting pulse oximetry
• Heart lesion

The second aim will be to characterize the hourly variation in pulse oximetry from these patients. The following information will be collected:

• Hourly pulse oximetry readings
• Heart lesion
• Clinical course