Recent evidence demonstrates that perioperative pain continues to be poorly managed among ambulatory surgical patients. More importantly, few interventions that minimize postoperative pain have also shown to improve patient overall quality of post-surgical recovery. Ketorolac has been used to minimize perioperative pain despite the lack of evidence for its use when administered as a single dose preventive strategy.Ketorolac has also been associated with a higher incidence of perioperative hematomas and the need for surgical re-exploration after breast surgery.

Systemic acetaminophen has become recently available in The United States. In contrast to ketorolac, systemic acetaminophen has not been reported to have adverse side effects on patients undergoing breast surgery. Although evidence suggests that a single dose perioperative acetaminophen reduces postoperative pain, it remains unknown if a single dose intravenous acetaminophen improves postoperative quality of recovery after ambulatory surgery.

The main objective of the current investigation is to evaluate the effect of a single dose systemic acetaminophen on postoperative quality of recovery after ambulatory breast surgery. We also seek to determine if systemic acetaminophen would decrease postoperative pain and the time to hospital discharge in the same population.

Significance: The current project evaluates a potential intervention to improve perioperative pain and recovery after ambulatory breast surgery. Postoperative pain in the ambulatory surgical patients has been shown consistently to be poorly managed.

Patients will be recruited up to the day of surgery. They will be then randomized using a computer generated table of random numbers to two groups: Group A (IV acetaminophen 1000 mg over 15 minutes at the start of surgical closure) and Group B (placebo group-same volume of saline solution administered in the same fashion).This dose has been commonly used in other studies involving IV acetaminophen.6 Both drugs will be identical and will be prepared by hospital pharmacy. After placement of standard ASA monitors, induction will be performed with 0.1mcg/kg/min of remifentanil IV, propofol 1.5-2.5 mg/kg IV and succinylcholine 1-2 mg/kg IV. Tracheal intubation will be performed using a MAC 3 blade and a size 7 endotracheal tube. Maintenance will be achieved with remifentanil infusion titrated to keep the blood pressure within 20% of baseline values and sevoflurane titrated to keep a bispectral index monitor between 40 and 60. Patients will receive ondansetron 4mg IV and dexamethasone 4 mg IV for postoperative nausea and vomiting prophylaxis. In the recovery room patients will receive hydromorphone IV in divided doses to keep pain <4/10(scale where 0 means no pain and 10 is the worst pain) and metoclopramide 10 mg IV as rescue antiemetic. Data will be collected by a research assistant blinded to the group allocation. Data collected will involve pain at PACU arrival (NRS-0-10), presence of nausea and vomiting, severity of nausea and vomiting, total opioid consumption in PACU, time to discharge using a Modified Postanaesthetic Discharge Scoring System (MPADSS) 9, total opioid consumption 24 hours, QoR40 24hours after surgery.8

Inclusion Criteria:

• Outpatient lumpectomy
• ASA I and II
• Age between 18-70

Exclusion:

• Pregnancy
• History of liver disease
• Unable to understand the informed consent
• Chronic pain with use of opioid in the last week
• Allergy to acetaminophen

Drop-out: surgeon or patient request

Development of nausea 24 hours after surgery.