Epidural meperidine does not cause hemodynamic changes in the term parturient

Purpose: Meperidine has local anesthetic properties and, therefore, when gi ven epidurally it has the potential to cause hemodynamic changes. Our objec tive 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 Ce sarean section under epidural anesthesia. Methods: A lumbar epidural catheter was inserted and patients lay in the su pine left wedge position. Intravenous fluid preload was withheld, and hemod ynamic measurements comprising of mean arterial pressure, cardiac output an d heart rate were made using automatic oscillotonometry (Dinamap 1486SX) an d transthoracic electrical bioimpedance (Bomed NCCOM3). Following baseline measurements, the hemodynamic effects of sequential epidural injection of f irst, 10 ml saline, and 20 min thereafter, 50 mg meperidine diluted to 10 m i 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 valu es in the mean (SD) cardiac output of 5.81 +/- 1.44 to 6.04 +/- 1.54 L.min( -1) (P < 0.05), and mean arteria[ pressure of 77.1 +/- 8.8 to 79.3 +/- 9.9 mmHg(P < 0.05). Sensory changes, the upper level of which ranged from LI to Tt, were detected in 94% of patients given epidural meperidine. Epidural s aline injection had no such hemodynamic effects, but produced a detectable sensory revel in two patients. Conclusion: Epidural meperidine, 50 mg, caused minimal hemodynamic changes in term parturients.