Ex vivostudies have suggested that high dose proton pump inhibitors (PPI) may have negative inotropic effects in myocardial tissue. We sought to investigate this concept in a real-world clinical setting. In this case series, we enrolled critically ill patients in the coronary and cardiothoracic intensive care units who had a preexisting pulmonary artery (PA) catheter in place for hemodynamic monitoring and were on a PPI for prespecified clinical indications. Hemodynamic measurements were made at baseline and then at 15 minute intervals for 1 hour after PPI administration. A total of 18 patients were evaluated; 72% were male with a mean age of 59.9 years. A total of 9 patients were evaluated on 2 consecutive days, yielding 26 patient-exposures to the medication. The majority of patients (72%) were receiving 1 or more inotropic agents (n = 6), a vasopressor (n = 4), or both (n = 4). When compared to baseline values, there was no significant change in mean arterial pressure (baseline 80 ± 11 mm Hg), heart rate (87 ± 11 bpm), or Fick cardiac index (2.7 ± 1.8 L/min/m 2 ). Mean PA pressure did decrease transiently at 45 minutes following PPI administration (28.5 ± 7.7 mm Hg at baseline vs 26.5 ± 7.5 mm Hg, P = 0.017), but is unlikely to be of clinical significance. In conclusion, these data suggest that IV PPIs do not immediately impact important hemodynamic parameters and are likely safe in a high-risk intensive care setting.