Clonidine, doxapram and ondansetron for treatment of postoperative shivering

ABSTRACT

Postanethetic shivering is a rhythmic movement, predominantly involving the upper limbs, neck and jaw, that occurs in 5-70% of patients recovering from general anesthesia. Postanethetic shivering may produce complications especially in patients with coronary artery disease, secondary to increased oxygen consumption, cardiac output, carbon dioxide production and circulating catecholamines and decrease mixed venous saturation. 60 patients classified as ASA physical status I and II were divided, in recovery room, into 3 groups [n=20] to treat postoperative shivering. Group [1] received clonidine 75 micro g, group [2] doxapeam 60mg and group [3] ondanosetron 8mg Temperature was recorded at the start of surgery, lowest temperature during operation and temperature at the end of surgery. In recovery room shivering score was recorded before drug and 5, 10, 20 and 30min after. Heart rate, mean blood pressure and temperature were measured at arrival, 5, 10, 20, 30, 60 and 90 min after. Side effects as tachycardia, bradycardia, hypertension, hypotension, sedation, persistence of shivering, more than grade II, for more than 5 min and recurrence of shivering after 20 min were recorded. Shivering score, allover the study, decrease significantly in group [1] compared to group [2] and [3], also decrease in group [2] compared to group [3]. Hypotension, bradycardia and sedation were associated with clonidine. Hypertension and tachycardia were associated with doxapram. Persistence of shivering was more in group [3] while reoccur of shivering was more in group [2]. Clonidine, doxapram and ondanosetron can be used to treat postoperative shivering, but clonidine is superior to doxapram and ondanosetron. Side effects of clonidine like hypotension, bradycardia and sedation must be in consideration especially in haemodynamically instable patients. Doxapram can be used in hypotensive patients, but avoid it if there is hypertension or tachycardia. On the other side ondanosetron has innocuous effects on the cardiovascular system. Persistence of shivering is more with ondanosetron while reoccurs, after 20min, is more with doxapram