Low Dose Ketamine Study on Opioid Tolerance and Hyperalgesia

Phase 4

Completed

Brief Summary: The purpose of this study is to:

1. Establish whether ketamine can decrease opioid consumption and modulate the onset of opioid tolerance and prevent opioid-induced hyperalgesia in pediatric subjects, ages 10 years to 18 years, undergoing posterior spinal fusion and instrumentation.

Recruitment & Eligibility

Inclusion Criteria

The subject is 10 to 18 years of age
The subject's American Society of Anesthesiologists physical status is ASA 1, 2 or 3 (see appendix I)
The subject is scheduled for elective posterior spinal fusion and instrumentation.
The subject's parent/legally authorized guardian has given written informed consent to participate

Exclusion Criteria

The subject has a history or a family (parent or sibling) history of malignant hyperthermia
The subject is pregnant or nursing.
The subject has known significant renal disorders determined by medical history, physical examination or laboratory tests
The subject has a known or suspected allergy to morphine, remifentanil or ketamine
The subject is an ASA classification of 4 or greater (See Appendix I)
The subject is scheduled for a surgical sub-procedure (i.e. anterior spinal fusion)
The subject is unable to self-administer morphine using patient-controlled analgesia (PCA) pump
The subject had a recent opioid exposure (within 1 month of surgery)
The subject is obese (body mass index >30kg/m2)
The subject is planned for elective postoperative ventilation
The subject has a known ocular disease not permitting pupillometric examination
The subject has used any investigation products in the past 30 days

Arm && Interventions

Group	Intervention	Description
Normal Saline	Normal Saline	Normal Saline given 0.5mg/kg intravenous (IV) load followed by an intraoperative continuous infusion at 0.25mg/kg/h and a postoperative infusion at 0.1mg/kg/h
Ketamine	Ketamine	ketamine 0.5mg/kg intravenous (IV) load followed by an intraoperative continuous infusion at 0.25mg/kg/h and a postoperative infusion at 0.1mg/kg/h

Primary Outcome Measures

Name	Time	Method
Morphine Equivalent Consumption (mg/kg)	at 24, 48, 72, 96 hours post operatively	Morphine consumption (mg/kg) was measured over time in the Ketamine group and compared to the Control (saline) group. Values are for each 24 hour time period and displayed as hours post surgery.

Secondary Outcome Measures

Name	Time	Method
Sedation Score	24, 48, 72, 96 hours post operatively	Sedation scores 0 = completely awake 1. = sleepy but responds appropriately 2. = somnolent but arouses to light stimuli 3. = asleep but responsive to deeper physical stimuli 4. = asleep and not responsive to any stimuli Values are for each 24 hour time period and displayed as hours post surgery.
Pain Score During Cough.	24, 48, 72, 96 hours post operatively	Patient volunteered response during a cough, 1-10 scale (where a higher score indicates more pain and a lower score indicates less pain). Values are for each 24 hour time period and displayed as hours post surgery.
Pain Score at Rest	24, 48, 72, 96 hours post operatively	Patient volunteered response at rest, 1-10 scale (where a higher score indicates more pain and a lower score indicates less pain). Values are for each 24 hour time period and displayed as hours post surgery.