The effects of pre-operative dexmedetomidine infusion on hemodynamics in patients with pulmonary hypertension undergoing mitral valve replacement surgery

Background: The aim of this study was to investigate the effects of pre-operative dexrnedetomidine infusion on hemodynamics in patients with pulmonary hypertension undergoing mitral valve replacement surgery. Methods: Patients were randomly divided into placebo (group P, n = 16) and dexmedetomidine (group D, n = 16) groups. In group D, a 1 mu g/kg bolus dose of dexmedetomidine was administered 10 min before the induction of anesthesia, followed by a 0.4 mu g/kg/h infusion until the surgical incision. Anesthesia was induced with lidocaine (1 mg/kg), midazolarn (0.2 mg/kg) and fentanyl (5 mu g/ kg) in both groups. Anesthesia was maintained with 0.5% isoflurane and fentanyl depending on the hemodynamic situation. The hemodynamic values during the investigation were obtained. Results: In group D, the mean arterial pressure (MAP), mean pulmonary arterial pressure (MPAP) and pulmonary capillary wedge pressure (PCWP) were decreased effectively in comparison with the values in the placebo group (P < 0.05), and there was an attenuation in the increase in the systemic vascular resistance index (SVRI) and pulmonary vascular resistance index (PVRI) at the post-sternotomy period. Conclusions: The pre-operative administration of the alpha(2)-agonist dexmedetomidine decreases the fentanyl requirement and attenuates the increase in SVRI and PVRI at the post-sternotomy period relative to the baseline levels, and decreases effectively MAP, MPAP and PCWP in comparison with the values in the placebo group, in patients with pulmonary hypertension undergoing mitral valve replacement surgery.