FAST-TRACKING AFTER CARDIAC SURGERY

Abstract

S111 INTRODUCTION: In a recent study, Chaney et al. [1] reported that a 10 [micro sign] g/kg dose of intrathecal morphine produced prolonged ventilatory depression in patients undergoing cardiac surgery with fentanyl-based anesthesia. Therefore, we designed a study to compare intrathecal morphine (8 [micro sign] g/kg) in combination with systemic remifentanil to systemic sufentanil alone when administered as adjuncts to a desflurane-based anesthetic technique for cardiac surgery. METHODS: 33 consenting patients undergoing coronary artery surgery were randomly assigned to one of two different analgesic groups according to an IRB-approved study. All patients were premedicated with midazolam, 20-30 [micro sign] g/kg IV. Prior to induction of general anesthesia, patients in the intrathecal (IT) group received morphine, 8 [micro sign] g/kg IT. Anesthesia was induced with sufentanil, 0.3-1[micro sign] g/kg, etomidate, 0.2-0.3 mg/kg and rocuronium, 0.6 mg/kg. In the IT group (n=16), maintenance of anesthesia consisted of desflurane 3-10% in combination with a remifentanil infusion, 0.1 [micro sign] g/kg/min. In the second group (n=17), patients received desflurane 3-10% in combination with sufentanil, 0.3 [micro sign] g/kg/h, for maintenance of anesthesia. Criteria for extubation included a clear sensorium, normothermia, hemodynamic stability, adequate pulmonary function, adequate urine output and minimal chest tube output. After extubation, patients received PCA hydromorphone (bolus dose = 0.15 mg, lockout interval = 10 min). The time interval from arrival in the ICU to extubation was recorded. Postoperative pain scores (using a 100-mm VAS scale, 0=none to 100= severe), as well as the cumulated dosage of hydromorphone were recorded at 1, 2, 4, 8, 12 and 24 hours after extubation. Opioid-related side effects were also noted. Data were analyzed using ANOVA or Kruskual-Wallis tests and Chi-squared test, with p <0.05 considered statistically significant (*) (mean values +/- SEM). RESULTS: The two groups were similar with respect to demographic data, type of oardiac operation, CPB and cross-clamp times. There were no differences between the groups with respect to time from ICU arrival to extubation (Table 1). At extubation, the intrathecal morphine group had significantly lower VAS scores and PCA hydromorphone usage, and this difference persisted for 24 hours postoperatively (Figure 1). Respiratory depression and urinary retention were not present in any patient and the incidences of nausea, vomiting and pruritis were similar in both groups (Table 1)Table 1Figure 1DISCUSSION: In this preliminary study, intrathecal morphine (8 [micro sign] g/kg) in combination with a systemic remifentanil infusion provided excellent intraoperative hemodynamic stability, significant postoperative analgesia and a low incidence of side effects without prolonging the extubation time compared with a standard systemic dose of sufentanil for cardiac anesthesia.