The purposes of the study are to identify 1) the patient (demographic and clinical) and health care system factors predictive of immediate and late postoperative adverse outcomes in children undergoing tonsillectomy. 2) Evaluate the preoperative use of the sleep questionnaire to identify children at risk for immediate and late postoperative adverse outcomes in children undergoing tonsillectomy.

Currently, children are scheduled to go home or stay in the hospital depending on expert consensus and institutional guidelines. The investigators preliminary experience (Dr. Sadhasivam PI: IRB No. 2008-0848) with the pharmocogenetic study, studying the phenotypic and genotypic influences of pain and use of opioids in patients undergoing tonsillectomy indicates that a significant number of patients scheduled as outpatients experience prolonged recovery phases in the PACU, some of whom are admitted or re-admitted following discharge. The identification of those factors that are, predictive of adverse events in tonsillectomy patients and the development of a prototype prediction model in this single-center study to support clinical decision-making. The rationale of this project is that developing a model to predict postoperative adverse events will not only lead to improved clinical outcomes and enhance patient safety, but also reduce family psychosocial distress associated with unanticipated hospital visits or re-admission, while reducing the burden on the health care system.

Inclusion Criteria:

• Children 0-17 years of age
• Children scheduled for tonsillectomy or adeno-tonsillectomy
• ASA I, II, or III

Exclusion Criteria:

• ASA IV and V

Children undergoing adenotonsillectomy in the United States