Continuous Oxygen Saturation Monitoring during Cardiac Catheterization in Adults: Conclusion
In an attempt to determine the factors that would be most predictive of arterial oxygen desaturation, we examined factors related to minimum Sa02. Three factors were found to be independent predictors: (1) low baseline Sa02; (2) the duration of the procedure; and (3) indices of left ventricular failure such as increased pulmonary arterial diastolic pressure, pulmonary capillary wedge pressure, end-diastolic volume, and decreased cardiac index. Five (63 percent) of the eight patients with symptoms or signs of heart failure before catheterization had episodes of arterial hypoxemia (Sa02 <90 percent) during the procedure. Thus, patients with congestive heart failure before catheterization or ventricular dysfunction found at catheterization are at increased risk of hypoxemia. buy antidepressants online
The duration of the procedure was associated with the occurrence of hypoxemia. Episodes of desaturation occurred in our population when sedated patients were lying quietly, without stimulation, for up to 20 minutes, during preparation for catheterization. In our population, arterial hypoxemia occurred in more than one-third of the patients during cardiac catheterization. These results were observed in patients predominantly undergoing elective cardiac catheterization (the one patient who was not elective did not have episodes of arterial hypoxemia). A more acutely ill population may have a different incidence of arterial hypoxemia.
Noninvasive monitoring of Sa02 by pulse oximetry does not require any calibration of instruments before it is used. Less than a minute is required to apply the noninvasive probe to the patients digit and determine the patients Sa02. In the light of our findings of the frequency and duration of hypoxemia during cardiac catheterization and the factors which appear significant in causing this hypoxemia, we would recommend considering use of pulse oximetry during cardiac catheterization and suggest supplemental oxygen or continuous pulse oximetric monitoring during cardiac catheterization in patients who (1) have decreased left ventricular function evidenced by a history of congestive heart failure, an increased left ventricular end-diastolic volume, increased pulmonary capillary wedge pressure, or decreased cardiac index; (2) have low baseline Sa02; or (3) are expected to have a long procedure.