The Efficacy of Intravenous Acetaminophen During Perioperative Neurosurgery Period

This is a prospective randomized double blinded trial study involving 128 patients undergoing any craniotomy procedure at Evanston Hospital. The patients will be randomized by the sealed envelope technique. The anesthesiologist and nurses who will be administering the placebo or intravenous acetaminophen will be blinded to the group in which patients are assigned.

The following information will be recorded for each patient enrolled in this study:

• Patient information/Preoperative Data

• Age, sex, height, weight,
• Disease specific information
• Primary diagnosis
• Pertinent medical history
• Medications
• Pertinent changes in patient status
• Procedural information

• Operation type
• Preoperative anesthetic medications
• Induction meds, intra-operative anesthetic meds, and post-operative anesthetic meds
• Duration of Surgery and Intubation
• Amount of dilaudid equivalent narcotics
• Postoperative Information

• Amount of narcotics administered in the PACU
• Amount of narcotics administered in the first 24 hour postoperative period
• Amount of non-narcotic analgesics administered in the first 24 hour postoperative period
• Time to first rescue analgesic in the PACU
• Amount of first rescue medication recorded
• Assessment of Pain Intensity at T0.5 (30min into PACU stay) and T24 (24 hours after end of surgery) (A 10-cm VAS scale will be used and labeled no pain at its left terminus and worst pain imaginable at its right terminus)
• Temperature in degrees centigrade every 8 hours for 24hours.
• CAM-ICU is performed by ICU nurses to detect delirium in patients every 8 hours and will be documented on a data collection sheet for the first 24 hours
• RASS is a sedation scoring system that is used in our ICU and is documented every 8 hours by ICU nursing. We will record the RASS score for the first 24 hours on a data collection sheet as documented by the ICU nurse.
• Overall satisfaction score at 24 hrs. "Overall satisfaction with pain management" (verbal rating score: scale 1 - 100)

Based on a pilot study (N-20) we expect that 25% of the placebo treated patients will require no opioids in the first 24 hour postoperative period. With the use of intravenous acetaminophen, it is hypothesized that the number of patients that do not require opioids in the first 24 hours after surgery will double.

Inclusion criteria

• Subject are able to provide informed consent prior to participation in the study
• Subjects must be scheduled to undergo elective open craniotomy procedure of > 2 hour duration
• Subjects must be >18 years old but less than 90 years old
• Subjects must have an American Society of Anesthesiologists (ASA) class I-IV
• Subjects must have the ability to communicate meaningfully with the investigator staff and read/understand the study procedures and the use of pain scales

Exclusion criteria

• Subjects used opioids or tramadol daily for >7 days before study medication administration
• Subjects had been treated with any of the following within 14 days of surgery: chaparral, comfrey, germander, jin bu huan, kava, pennyroyal, skullcap, St. John's wort, or valerian
• Subjects who have a chronic pain condition, significant medical disease or laboratory abnormality that in the investigator's judgment could compromise the subject's welfare
• Subjects with known hypersensitivity to opioids, acetaminophen or the inactive ingredients
• Subjects with known or suspected history of alcohol or drug abuse or dependence in the previous 2 years prior to the proposed surgery