inability to obtain equipment and lack of funding.

Pain assessment in infants and toddlers is quite challenging since children in these populations are nonverbal or preverbal and cannot describe the presence and severity of pain that they perceive. Over the last decade, advances in the field have included the development of behavioral scoring systems for the assessment of acute pain . However, although they have been validated, these commonly used methods of pain assessment are largely subjective and rely on a highly trained observer. An objective continuous measure of pain would be an important addition to standard behavioral pain scores which require nurses to monitor the child's behavioral responses.

After standard general anesthetic mask induction, 0.5 ml of blood will be drawn for genetic analysis when the intravenous catheter is sited. A member of the research team will manually transport an appropriately-labeled blood collection tube to the Department of Anesthesiology Perioperative Genomics Laboratory for storage and further preparation for genetic analysis. The samples will be stored until the investigators have enough to process. The results will be stored in a secure database. The surgical procedure, anesthesia technique, intraoperative analgesia treatment and initial postoperative analgesia treatment will be standardized.Upon arrival in the Post-Anesthesia Care Unit (PACU), the child will be connected to standard monitors as per standard of care. Pain scores will be recorded on a scale of 0-10 (FLACC, Face, legs,activity, cry, consolability scale) scale. A member of the research team will apply the skin conductance (SC) monitor on the child's hand or foot.This will be used to measure SC values that will be saved on a laptop computer and the SC data will be analyzed off-line.

Inclusion Criteria:

• Children <5 years of age
• Presenting for palatal repair (palatoplasty) or tonsillectomy/adenoidectomy
• American Society of Anesthesiologists (ASA) physical status of 1 - 3

Exclusion Criteria:

• Children > 5 years of age
• On chronic pain treatment
• Pre-operative use of analgesics
• Allergies to any anesthetics or analgesia products
• Diagnosis of Cystic fibrosis
• American Society of Anesthesiologists (ASA) physical status > 3

The study population will be children less than 5 years of age presenting for palatoplasty or tonsillectomy/adenoidectomy. These will be otherwise healthy children, ASA physical status 1 - 3.