Introduction: Postoperative shivering after cardiac surgery following hypothermic cardiopulmonary bypass (CPB) occurs in 40-50% of patients. The efficacy of the opioid meperidine in cardiac surgery patients for the treatment of shivering is not more than 50% . The aim of this study was to assess by a clinical estimation , the therapeutic efficacy of the opioid tramadol in the management of postoperative shivering in cardio-surgical patients.
Method: 50 adult patients with postoperative shivering after coronary and valvular surgery with hypothermic CPB were assigned to two equal groups. Group 1 were treated with a bolus of 100mg tramadol (Tramal Grunenthal GMBH, Germany). Group 2 received a bolus of saline placebo. The study was conducted in double blind fashion. Intensity of shivering was estimated in accordance with a previous classification : grade 1 - mild fasciculation of face and neck; grade 2 - shivering involving face, neck, upper extremities or thorax; grade 3 - generalized shivering. All patients were mechanically ventilated. Data (mean and SD) were analysed with Student's t-test.
Results: The demographic and clinical data of patients in the two groups were comparable. Tramadol was administered in a dose of 1.48 ± 0.25 mg/kg. The incidence of postoperative shivering and efficacy of tramadol are presented in the table.
Analysis did not show significant changes in the mean values of ABP and HR. There was a slight increase of sedation in 10 patients.
Discussion: Tramadol has a dual mechanism of action. In addition to an affinity for opioid receptors it also inhibits reuptake of serotonin and norepinephrine that play a certain role in thermoregulation. Perhaps this mechanism explains why tramadol is more effective than pure opioids.
Conclusion: Tramadol was highly effective in decreasing shivering after cardiac surgery and it did not have significant effect on blood pressure or heart rate. Tramadol is useful in the management of postoperative shivering in cardiosurgical patients.
1 Cruise C, Mackinnon J, Tongh J, et al. Comparison of meperidine and pancuronium for treatment of shivering after cardiac surgery. Can J Anesth
2 De Witte JL, Kim JS, Sessler DI, et al. Tramadol reduces the sweating, vasoconstriction, and shivering thresholds. Anesth Analg
3 De Witte J, Rietman G, Vandenbroucke G. Postoperative effects of tramadol administered at wound closure. Eur J Anesthesiol