Should All Patients Undergoing Cardiac Catheterization or Percutaneous Transluminal Coronary Angioplasty Receive Oxygen?

Supplemental oxygen is routinely administered to patients with acute coronary syndromes. The risk of significant morbidity during cardiac catheterization or coronary angioplasty has been well described; however, to our knowledge, the need for routine oxygen supplementation in these patients has not been investigated. In phase 1, we prospectively studied 142 patients undergoing diagnostic cardiac catheterization (n = 94) or percutaneous transluminal coronary angioplasty (PTCA) (n = 48) to determine the incidence of procedure-related hypoxemia (pulse oximetry derived oxygen saturation [SpO2] < 90 percent of > 1 min duration) while breathing room air (RA). In phase 2, 134 patients undergoing diagnostic cardiac catheterization (n = 78) or PTCA (n = 56) were randomly allocated to breathe either RA or supplemental oxygen (O2, 6 L/min by nasal cannula) to determine the effect of oxygen administration on procedure-related hypoxemia. Oximetry results were compared with pertinent clinical and procedural data that might predispose patients to develop hypoxemia. Phase 1—Moderate to severe hypoxemia occurred in 36 percent (34/94) of patients undergoing diagnostic catheterization and in 56 percent (27/48) of patients undergoing PTCA. In the diagnostic catheterization group, there were a total of 25 episodes of moderate hypoxemia (SpO2 85 to 89 percent) lasting 4.0 ± 4.3 min and 11 episodes of severe hypoxemia (SpO2 < 85 percent) of greater duration, 11.7 ± 7.5 min (p 95 percent. Phase 2—Oxygen therapy was associated with a reduction in the incidence of hypoxemia from 42 percent to 5 percent (RA vs O2, p < 0.001) in the diagnostic catheterization group and 39 percent to 11 percent (RA vs O2, p < 0.03) in the PTCA group. Significant hypoxemia is a commo