Abstracts of Posters Presented at the International Anesthesia Research Society; 72nd Clinical and Scientific Congress; Orlando, FL; March 7-11, 1998: Cardiovascular Anesthesia
Non-depolarizing neuromuscular blockade is employed during the anesthetic management of aortic valve replacement (AVR) surgery. Traditionally, the presence of residual neuromuscular blockade at the conclusion of surgery was of little consequence, since these patients remained tracheally intubated and mechanically ventilated overnight. However, early extubation of these patients (Fast Track) demands the restoration of neuromuscular function for adequate spontaneous respiration and airway protection. [1,2] This study examined the hemodynamic responses to the reversal drugs, glycopyrrolate and neostigmine, after AVR.
METHODS: After IRB approval, informed consents were obtained from 10 patients scheduled to undergo elective AVR. Excluded were patients undergoing combined procedures, and patients requiring inotropic or intraaortic balloon counterpulsation support. In the operating room, routine monitors were applied and catheters were inserted into the radial and pulmonary arteries. Hemodynamic variables were measured or calculated, including cardiac index (CI), mean arterial pressure (MAP), heart rate (HR), mean pulmonary artery pressure (MPAP), pulmonary capillary wedge pressure (PCWP), right atrial pressure (RAP), stroke volume (SV), and systemic and pulmonary resistance indices (SVRI & PVRI). Anesthesia was maintained with fentanyl and propofol. Neuromuscular blockade was accomplished with vecuronium. At the conclusion of surgery, the study protocol was begun. Baseline hemodynamic measurements, ECG tracing (Leads II & V) and arterial blood gases were obtained. A mixture of glycopyrrolate (10 [micro sign]g/kg) and neostigmine (50 [micro sign]g/kg) was administered, and hemodynamic measurements and ECG were obtained at 2, 4, 6, 8, 10, and 20 min post-reversal. After conclusion of the study protocol, the patients were transferred to the intensive care unit and scheduled for tracheal extubation within 2-4 hours.
RESULTS: There were no arrhythmias, ST segment or other ECG changes, or significant hemodynamic changes during the study period (Table 1). All patients were extubated within 2-4 hrs of the completion of the protocol.
CONCLUSIONS: The present study demonstrates that reversal of neuromuscular blockade with glycopyrrolate and neostigmine in patients undergoing AVR is not associated with untoward ECG or hemodynamic consequences. Reversal should not be withheld because of concerns of undesirable hemodynamic changes.
1. J Cardiothorac Vasc Anesth 1995; 9(Suppl 1):30
2. J Cardiothorac Vasc Anesth 1995; 9 (Suppl 1):10.