effect of cryoanalgesia on post midsternotomy pain and paresthesia following cabg

introduction: control of post thoracotomy pain is particularly important in prevention of post operative respiratory complications. several methods are proposed for control of postoperative pain. cryoanalgesia by freezing of intercostal nerves is able to providing long term pain relief in post operative period which probably results in cutaneous sensory changes. methods: this clinical trial study was done on 124 patients who underwent cabg surgery. patients were randomly divided in two groups control group (group i) and study group (group ii). in study group cryoanalgesia was applied intraoperatively on the intercostal nerves. all of the patients received appropriate analgesia on demand in postoperative period. pain in lima harvesting site and sternum was measured by visual analogue pain score before discharge, one and three months following cryoanalgesia. in all of the patient’s, presence of paresthesia was evaluated. the amount of administered analgesics (narcotic, opium, indomethacin) was noted daily. data of this investigation was analyzed and evaluated using spss 11.5 software. results: pain score of sternum was higher in study group before discharge and was lower at one and three months after operation than the control group that was statistically significant (p=0.01). pain score of lima region before discharge was higher, at one month post operation was equal and at three months post operative was lower than the control group (p=0.045). use of morphine and opium was lower (p=0.017) and use of indomethacin was higher in the cryoanalgesia group that was statistically significant (p=0.001). incidence of paresthesia was lower in the study group (p=0.001). conclusion: it is proposed that cryoanalgesia is a safe and effective method for reduction of pain and paresthesia and need for analgesics following cabg operation.