A Randomized Controlled Trial to Compare Pain Medications in Children Undergoing Strabismus Surgery

Research Design This is a randomized clinical trial with masked assessment, comparing recovery indices for patients receiving longer acting versus shorter acting opiate analgesia using hydromorphone or fentanyl as intraoperative analgesics. An otherwise standardized anesthetic and analgesic regimen will be utilized, as consistent with routine care at the research institution.

Sample and Setting Patients included will be children age 3 through 10 years scheduled for strabismus surgery. The procedure may also include scheduled exam under anesthesia (EUA) of the eyes, but any other surgical procedure in conjunction with strabismus will be excluded from enrollment. Review of anesthesia records shows that 480 patients met inclusion criteria for the preceding 12 months. The primary outcome measure is pain as measured by the revised Faces, Legs, Anxiety, Cry & Consolability scale (rFLACC). Based on previous pilot work, the investigators expect pain scores to have a mean of five and a standard deviation of two. The goal is to detect a change of one point in rFLACC scores, which the investigators believe would be clinically significant. With alpha of 0.05 and power of 0.80, the investigators would need 64 patients in each arm for a one point decrease in rFLACC scores to be statistically significant. The investigators expect that ten percent of patients will have to be dropped because of missing data, so the investigators are proposing to enroll 71 patients in each arm (142 patients total) in order to have data for 64 patients in the analyses.

Inclusion criteria will be 1) children ages 3 to 10 years old having strabismus surgery for the first time, a repeated strabismus surgery, or an eye examination for strabismus under anesthesia; 2) the child has to be evaluated as an American Society of Anesthesiologists Physical Status (ASAPS) classification Class 1 or 2; 3) the caregiver should be present in the hospital; and 4) the child and caregiver must be English speaking. Exclusion criteria will include 1) children evaluated as an ASAPS Class 3 or 4; non-English speaking children or parents; 3) additional surgery performed at the same time; 4) children with documented behavioral disabilities; 5) prior participation in the study.

Tools A researcher developed demographic questionnaire will be used to collect information from a parent that includes patient age, gender, previous surgery, any medication allergies, and primary caregiver. The Amsterdam Preoperative Anxiety and Information Scale (APAIS) will be used to assess parent feelings of anxiety in the preoperative phase. The APAIS is short 6-item questionnaire with acceptable reliability with Cronbach's alpha greater than or equal to 70 and correlated highly (0.74) with the widely used State Trait Anxiety Scale. Because of its length, the APAIS can be quickly administered to parents of children undergoing surgery in order to assess parental preoperative anxiety . The measure will be completed on all parent participants after consent is obtained. The tool takes approximately 1-2 minutes to score.

For evaluating anxiety in children the Modified Anxiety Scale (mYPAS) will be used. The mYPAS is frequently used to measure anxiety prior to induction and has demonstrated both inter and intra-rater reliability (using k statistics) ranging from 0.63 - 0.90 and acceptable reliability (p = 0.01, r = 0.79) The tool can be administered in less than one minute, is reliable in children ages 2-12 years, and uses five areas (activity, vocalization, expression, arousal, and interaction) to rate preoperative anxiety.