بيمارستان شهيد مدني تبريز ICU مقايسه اثرات انفوزيون مورفين با تزريق عضلاني متادون در تست هاي فونكسيون ريوي بعد از عمل در بيماران جراحي قلب باز در

Comparison between effects of Morphine infusion and IM injection of Methadone on pulmonary functions after cardiac surgery in Tabriz Shahid Madani Hospital ICU

One of the serious postoperative problems in cardiac surgery is the reduction of respiratory parameters such as SaO2, FVC, FRC, alveolar ventilation due to postoperative pain from sternotomy and chest tubes insertion. It results in atelectasis, hypoxia and hypercarbia. Also postoperative pain increases stress hormones concentration. High oxygen consumption and aggravation of myocardial ischemia is itʹs intolerable consequences. Establishment of postoperative analgesia is important for resumption of normal activities including ambulation, deep breathing and effective coughing. Regarding various analgesic techniques used today, in this study effects of IV infusion of morphine and IM injection of methadone compared on pulmonery function tests. In our clinical trial, 60 patients were randomly allocated and received two different methods of postoperative analgesia. Drugs injected one hour after tracheal extubation and continued for 24 hours posoperatively. In group 1 patients analgesia achieved by continous IV infusion of 30 mg/kg/h morphine and patients in group 2 treated with 0.1mg/kg/12h IM methadone. Pain assesed using Visual Analog Scale (VAS). ABGs and FVC (with incentive spirometry) were also performed. Vital signs and SaO2 monitored one hour after tracheal extubation and it was also computed every 6 hours for 24 hours. In this study patients received oxygen by nasal cannula with Fio2=36%. It was administered from extubation till subsequent 24 hour. According to the obtained results there was no significant difference between two groups from the point of cardiac F.C limit (Pvalue=0.7). FVC and VAS were also similar in both groups and significant difference was not found between two groups about their vital signs, SaO2 and ABGs limits. It is noticeable that decreasing postoperative pain paraleled with gradual increase of FVC about all the patients and in a period of 24 hours, FVC doubled in both groupes. No respiratory depression and fall in SaO2 noted. By having patients who are free of pain, understanding role of analgesia on prevention of sever cardiac complications and by improving pulmonary functions we can understand the role of postoperative analgesia about patientʹs overal - outcome. Besides similar analgesic effects of morphine and methadone researches of the present study recommend use of methadone because of not having problems for nursing team, no need to infusion pump, easy ambulation of patients, not haveing drug dependency after discharge from ICU and finally no accumulation effect of drug.