Background: It has been routine practice to keep patients undergoing cardiac stress testing nil per os (NPO) until the results of the test were reported. The rationale is to enable left heart catheterization the same day if the stress test is positive, thereby reducing time to coronary intervention and length of stay (LOS). Often, NPO status can last several hours and studies have shown that prolonged NPO status is linked with poor patient satisfaction. The specific aims of this study were to 1) quantify the number of patients who undergo stress test and subsequent same day heart catheterization and 2) estimate the average time patients are left NPO after completion of stress testing.
Methods: We conducted a retrospective single center analysis of 160 patients placed in our Observation Unit who were NPO and underwent cardiac stress testing. We determined the percentage of patients (with 95% confidence interval) undergoing stress testing who also underwent same day heart catheterization. We also determined the time between stress test results to discontinuation of the NPO order.
Results: The patient population included 99 females and 61 males with an average of 57 years. Of 160 patients undergoing a stress test, none of them underwent same day heart catheterization (95% CI 0-2.34%). Two patients (1.3%) had a positive stress test (95% CI 0.3-4.4%) and both underwent heart catheterization the next day. Of the 160 stress tests performed, 5% were inconclusive (95% CI 2.6-9.6%), but none underwent heart catheterization during that admission. Patients waited a mean of 2.03 hours (SD 2.51) and a median of 1.16 hours (IQR 0.23-3.32) after the stress test was reported until the NPO order was discontinued.
Conclusions: Clinical medicine is moving towards placing greater emphasis on the importance of patient satisfaction. It is important to implement protocols directed towards improving patient satisfaction. Importantly, prolonged NPO status has been correlated with negative patient satisfaction and experience. Our study indicated that the rate of same day heart catheterization in patients placed in observation for stress testing is low. These findings suggested that it is unnecessary to keep patients NPO following completion of stress test. Following this study, NPO protocols for stress tests were modified so patients could get a diet order immediately after completion of their stress test.