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EVALUATION OF THE EFFICACY AND WEANING PERIOD OF NITRIC OXIDE IN ADULT CARDIAC SURGERY PATIENTS

Ramsay, KJ BA; Ramsay, MAE MD; Lynch, K RRT; Hein, HAT MD; Lehman, VR RRT

doi: 10.1097/00000539-199802001-00093
Abstracts of Posters Presented at the International Anesthesia Research Society; 72nd Clinical and Scientific Congress; Orlando, FL; March 7-11, 1998: Cardiovascular Anesthesia
Free

Departments of Anesthesiology & Pain Management and Pulmonary Medicine, Baylor University Medical Center, Dallas, TX 75246; Department of Anesthesiology & Pain Management, UTSWMC, Dallas.

Abstract S93

Introduction: Nitric oxide (NO) is used as a selective pulmonary vasodilator in adult cardiac surgery patients with acute pulmonary hypertension and right heart dysfunction. In this study we report on a two-year experience with inhaled NO in patients undergoing cardiac bypass surgery and heart transplantation. This group of patients may encounter acute increases in pulmonary artery pressures (PAP), pulmonary vascular resistance (PVR), right heart dysfunction, and alveolar-arterial gradients, especially on separating from cardiopulmonary bypass. A review of the time taken to wean off the NO was also made.

Method: After FDA and IRB approval and informed consent, 24 patients met criteria to receive NO (systolic PAP >or=to 45 mm Hg, PVR > 180 dynes/s/cm5, transpulmonary gradient > 10 mm Hg, and/or right heart dysfunction). Nitric oxide was blended into the ventilatory circuit and monitored at the inspiratory limb of the Y-junction close to the endotracheal tube. Arterial blood gases were analyzed, NO and NO2 concentrations were closely monitored, and hemodynamic parameters were monitored continuously. The time taken to wean off NO was also analyzed and correlated with the duration of NO therapy. Data were analyzed using Student's t-tests and Pearson's correlations.

Results: (Table 1 and Table 2)

Table 1

Table 1

Table 2

Table 2

Conclusion: Nitric oxide is effective at reversing acute increases in PAP and PVR as well as improving right ventricular performance in select cardiac surgery patients. The amount of time spent on NO therapy correlated significantly with the time required to successfully wean off NO. It is of interest that over 25% of the weaning period is spent on reducing NO from 5ppm to 0ppm.

© 1998 International Anesthesia Research Society