K S Khaw1, W D Ngan Kee, L A Critchley. 1. Department of Anaesthesia and Intensive Care, Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, Peoples Republic of China. kimkhaw@cuhk.edu.hk
Abstract
PURPOSE: Meperidine has local anesthetic properties and, therefore, when given epidurally it has the potential to cause hemodynamic changes. Our objective was to study the hemodynamic effects of an analgesic dose of epidural meperidine (50 mg) in 34 ASA 1-2 term parturients scheduled for elective Cesarean section under epidural anesthesia. METHODS: A lumbar epidural catheter was inserted and patients lay in the supine left wedge position. Intravenous fluid preload was withheld, and hemodynamic measurements comprising of mean arterial pressure, cardiac output and heart rate were made using automatic oscillotonometry (Dinamap 1486SX) and transthoracic electrical bioimpedance (Bomed NCCOM3). Following baseline measurements, the hemodynamic effects of sequential epidural injection of first, 10 ml saline, and 20 min thereafter, 50 mg meperidine diluted to 10 ml with saline, were recorded. Sensory blockade was assessed following each injection using loss of temperature discrimination to ice. Paired Student t tests were used to compare changes in hemodynamic variables. RESULTS: Epidural meperidine produced a small increase from the saline values in the mean (SD) cardiac output of 5.81 +/-1.44 to 6.04+/-1.54 L x min(-1) (P<0.05), and mean arterial pressure of 77.1+/-8.8 to 79.3+/-9.9 mm Hg (P<0.05). Sensory changes, the upper level of which ranged from L1 to T1, were detected in 94% of patients given epidural meperidine. Epidural saline injection had no such hemodynamic effects, but produced a detectable sensory level in two patients. CONCLUSION: Epidural meperidine, 50 mg, caused minimal hemodynamic changes in term parturients.
PURPOSE:Meperidine has local anesthetic properties and, therefore, when given epidurally it has the potential to cause hemodynamic changes. Our objective was to study the hemodynamic effects of an analgesic dose of epidural meperidine (50 mg) in 34 ASA 1-2 term parturients scheduled for elective Cesarean section under epidural anesthesia. METHODS: A lumbar epidural catheter was inserted and patients lay in the supine left wedge position. Intravenous fluid preload was withheld, and hemodynamic measurements comprising of mean arterial pressure, cardiac output and heart rate were made using automatic oscillotonometry (Dinamap 1486SX) and transthoracic electrical bioimpedance (Bomed NCCOM3). Following baseline measurements, the hemodynamic effects of sequential epidural injection of first, 10 ml saline, and 20 min thereafter, 50 mg meperidine diluted to 10 ml with saline, were recorded. Sensory blockade was assessed following each injection using loss of temperature discrimination to ice. Paired Student t tests were used to compare changes in hemodynamic variables. RESULTS:Epidural meperidine produced a small increase from the saline values in the mean (SD) cardiac output of 5.81 +/-1.44 to 6.04+/-1.54 L x min(-1) (P<0.05), and mean arterial pressure of 77.1+/-8.8 to 79.3+/-9.9 mm Hg (P<0.05). Sensory changes, the upper level of which ranged from L1 to T1, were detected in 94% of patients given epidural meperidine. Epidural saline injection had no such hemodynamic effects, but produced a detectable sensory level in two patients. CONCLUSION:Epidural meperidine, 50 mg, caused minimal hemodynamic changes in term parturients.