The effect of topical tetracaine eye drops on emergence behavior and pain relief after strabismus surgery

Abstract

Pediatric strabismus surgery may be associated with postoperative nausea, vomiting, and emergence agitation (restlessness, thrashing, crying, moaning, disorientation). We hypothesize that emergence agitation after strabismus surgery is in part related to pain and that topical tetracaine ophthalmic drops can decrease the intensity and incidence of postoperative pain and emergence agitation. Eighty-eight subjects aged 1 to 12 years scheduled for strabismus surgery were enrolled in a double-masked randomized control trial. The patients were randomized to one of three groups: Group A received normal saline drops before and after surgery; Group B received normal saline drops before and tetracaine 1% drops after surgery; Group C received tetracaine 1% drops before and after surgery. An observer masked to group assignment assessed each patient in the postanesthesia care unit (PACU) using both a behavior scale and a modified behavioral pain scale. Patients in Group A were found to be in significantly more pain than Groups B or C at 5 minutes after arrival to the PACU (p < 0.013). Using the behavior scale, a significantly greater proportion of patients in Group A were crying or crying and thrashing at 5, 15, and 30 minutes after arrival to the PACU (5 minutes, p < 0.019; 15 minutes, p < 0.041; 30 minutes, p < 0.021). There was no significant difference between groups in total PACU time, PACU vomiting, PACU morphine use, or pain at home. Postoperative strabismus surgery pain was improved by the use of preoperative, and pre- and postoperative, tetracaine drops. Emergence agitation was not fully evaluated by the behavioral scale, and therefore, the effect of tetracaine drops on emergence agitation was not clarified. This study suggests that tetracaine drops can lead to a less stressful early postoperative experience for the patient.