بررسی مقایسه‌ای اثر تزریق 2 دوز مورفین اینتراتکال بر زمان خروج لوله نای پس از جراحی پیوند عروق کرونر

The object of the present study was to determine the effect of 2 doses of intrathecal morphine on extubation time and on postoperative analgestic requirements after coronary artery bypass graft surgery. This prospective, randomized, double blind placebo-control study was carried out on 60 adult patients(ASA II, ASA III) without emergency surgery, valvular heart disease, contraindication for spinal anesthesia or addiction. Patients (40-70 years old) were randomly divided to three groups to receive placebo, 3μg/Kg or 73μg/Kg interathecal morphine preoperatively. Intraoperative midozolame and fentanyl injection were limited to 153μg/Kg and 303μg/Kg intravenously. Patients were extubated in the intensive care unit by a blinded observer using predefined extubation criteria. Time to extubation and postoperative requirements for intravenous morphine was recorded by a blind observer. Patient in three groups did not have any significant difference in terms of age, weight or height. Extubation times were 465±207 minutes for placebo group and 414±245 minutes and 335±177 minutes for 3 μg/Kg & 7μg/Kg intrathecal morphine group(P=0.19). Postoperative morphine requirements in 3μg/Kg, 7μg/Kg and placebo groups were 18.8±7.8, 13.3±6.4 and 28.3±6.5(mg)(P=0.001). ABG analysis in three groups in ICU indicated that average Paco2 were 40.1±4.1, 43.6±6.5 and 47.9±4.8(mmhg) in placebo, 3μg/Kg and 7μg/Kg in intrathecal morphine groups respectively(P=0.001)(mean±SD). Despite decreased post operative morphine requirements, intrathecal morphine administration did not have a clinially relevant effect on extubation time after CABG surgery. This study suggests that 3μg/Kg intrathecal morphine is a suitable dose for providing significant postoperative analgesia without delaying tracheal extubation time and has minimum respiratory depression. Key Words: 1) Early tracheal extubation 2) Intrathecal opioid injection 3) CABG(Coronary Artery Bypass Grafting)