An epidural scoring scale for arm movements (ESSAM) in patients receiving high thoracic epidural analgesia for coronary artery bypass grafting

Abstract

Thoracic epidural analgesia appears to improve the outcome of patients undergoing coronary artery bypass graft surgery. Cranial extension of nerve blockade involving the third, fourth and fifth cervical nerve roots can cause apnoea. However, progressive paraesthesia and weakness due to cephalad spread of thoracic epidural analgesia will affect the arms before the diaphragm. A scale was designed to test three active movements of the arms bilaterally: hand grip (T1/C8), wrist flexion (C8/7) and elbow flexion (C6/5). This epidural scoring scale for arm movements (ESSAM) consists of four grades (0-3) based on the number of absent movements, and suggests appropriate action. The reliability of this scale was tested in 40 patients undergoing coronary artery bypass surgery. Twelve of the 40 patients had their epidural infusion reduced on the basis of the scale. Of these 12 patients, eight had a worst ESSAM score of 1, three had a worst score of 2, and one had a worst score of 3. In each patient, motor power returned following the reduction in infusion rate, taking between 30 min and 3 h. This scale appears to be a simple and reliable method for the early detection of the cephalad spread of thoracic epidural analgesia.