Evaluation of analgesia and hemodynamic changes of two drugs: remifentanil and morphine, during the time of Extracorporeal shock wave lithotripsy (ESWL)

Pain is the most common side effects of ESWL for treatment of renal stones and opioids are well known agents for analgesia during this procedure. Remifentanil is a new opioid, and have a very short half life compare with other agents of this group, and its elimination is independent of kidney and liver function and is metabolized by unspecific tissue and blood esterases. The effect of this opioid on hemodynamic and quality of analgesia during ESWL is not well known. We compared the effect of two drugs of morphine sulfate and remifentanil on hemodynamic alteration and quality of analgesia during ESWL, using a randomized double blind clinical trial study on 70 ASA Class I or II, 15-45 years of age patients with renal stone candidated for ESWL. In group R (n=35) remifentanil was administered at bolus of 0.1 mg/kg during 30 seconds and infusion of 0.05 mg/kg/min until pain was tolerated and continuous infusion of 0.025 mg/kg/min. Morphine Was administered at 0.1 mg/kg bolus to group M (n=35) that received infusion of normal saline. We recorded mean blood pressure (MAP) and heart rate (HR) and arterial blood oxygen saturation (SpO2) of all patients before administering drug, before the prtocedure and each 5 minutes during the procedure, and intensity of pain was estimated by VRS (Verbal Rating Scale). Comparing D MAP, D HR, D SPO2 between two groups had no meaningful change. Mean of D VRS was meaningfully lower during ESWL in remifentanil group compare with morphine group (p< 0.05). In summary, remifentanil in dose of 0.025 mg/kg min provided a better analgesia compared with morphine sulfate and had adverse effect on hemodynamic of patients, so we concluded that: remifentanil can be an appropriate substitute for morphine sulfate.