Aims: Prolonged tourniquet inflation produces a hyperdynamic cardiovascular response. We investigated the effect of continuous remifentanil infusion on systemic arterial pressure, heart rate, and cardiac output changes during prolonged tourniquet use in elderly patients under sevoflurane/N(2)O general anesthesia.
Methods: Thirty female patients scheduled for knee replacement arthroplasty were infused with either remifentanil at a target organ concentration of 2.0 ng/mL (remifentanil group, n = 15) or saline (control group, n = 15) after induction of anesthesia. Anesthesia was maintained with sevoflurane and N(2)O. Heart rate (HR), systolic arterial pressure (SAP), diastolic arterial pressure (DAP), cardiac index (CI), total systemic vascular resistance index (TSVRI), BIS, end-tidal sevoflurane concentration (EtSEVO), and end-tidal carbon dioxide concentration (EtCO(2)) were measured during the study period.
Results: There were significant differences in mean HR, SAP, DAP, and EtSEVO over time between the groups (P = 0.047, P < 0.001, P = 0.017, and P < 0.001, respectively). There was a statistically significant time trend effect (P < 0.001) in HR, SAP, DAP, and CI between the groups, with a statistically significant time-group interaction between the two groups (P = 0.02, 0.007, 0.001, 0.01, respectively).
Conclusion: The present study demonstrated that infusion with remifentanil prevented an increase in hemodynamic pressure during tourniquet inflation in elderly patients under sevoflurane/N(2)O general anesthesia.
Keywords: general anesthesia; knee replacement arthroplasty; remifentanil; tourniquet..