Some patients have respiratory depression (decreased breaths per minute) after surgery. Acetaminophen, an FDA approved pain medication, may prevent this problem. The purpose of this study is to determine if acetaminophen decreases respiratory depression after surgery. The investigators will also evaluate the cost effectiveness of acetaminophen. Patients having elective major abdominal surgery are being asked to participate in this research study. If eligible, a patient will have their baseline tidal volume (amount of air moved into or out of the lungs) and vital capacity (how much air the lungs are capable of holding) measured using a spirometer (apparatus for measuring the volume of air inspired and expired by the lungs) measured before surgery. Three questionnaires will also need to be completed before surgery. The patient will then be randomized, like flipping a coin, to receive either Acetaminophen or placebo (inactive substance) as an infusion throughout surgery and for the first two days thereafter. Neither the patient nor his or her physician will know if the patient is assigned to study drug or placebo. Regardless of study assignment, both groups will receive standard pain management medications and sedation. After surgery, the patient's blood pressure, activity, posture, respiratory rate, the electrical activity of the heart, oxygen saturation, tidal volume, minute ventilation and respiratory rate will be continuously monitored and recorded for 48 hours using a wireless pulse-oximeter and a respiratory volume monitor. 48 hours after surgery the patient will be asked to complete a patient satisfaction questionnaire, which will allow the patient to rate the satisfaction with the treatment received for pain. The patient will also be asked to complete a questionnaire about recovery. At discharge, the patient will be given two questionnaires about pain and quality of life.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
QUADRUPLE
Enrollment
580
Cleveland Clinic Foundation
Cleveland, Ohio, United States
Duration of Hypoxemia
Hypoxemia is measured as minutes with hypoxemia (Spo2 \<90%) per hour of successful Spo2 monitoring. Patients will have nearly continuous pulseoximeter monitoring and recording. Data from the monitor will be downloaded daily for 48 hours postoperatively.
Time frame: the initial 48 hours of postoperative monitoring or for the duration of hospitalization, if shorter.
Time-weighted Pain Score During Initial 48 Postoperative Hours
Pain scores were calculated on a visual analog scale of 0 to 10, with 0 being no pain and 10 being the most pain imaginable; time weighted mean was calculated as the area under the curve of the pain score measurements divided by total measurement time. Pain was recorded at roughly 15-minute intervals in the postanesthesia care unit and at 4-hour intervals on surgical wards
Time frame: Initial 48 postoperative hours or duration of hospitalization (whichever comes first)
Time Weighted Pain Score in Post Anesthesia Care Unit
Pain scores were calculated on a visual analog scale of 0 to 10, with 0 being no pain and 10 being the most pain imaginable; time-weighted mean was calculated as the area under the curve of the pain score measurements divided by total measurement time.
Time frame: Initial 48 postoperative hours or duration of hospitalization (whichever comes first)
Fatigue Score on Morning of Postoperative Day 1
Fatigue scores were calculated on a scale of 1 to 10, with 1 being no fatigue and 10 being the worst fatigue imaginable.
Time frame: Postoperative day 1
Lowest RASS Score During Initial 48 Postoperative Hours
Sedation was estimated by the RASS score and recorded at 2-hour intervals by ward nurses per clinical routine during the initial 48 postoperative hours. The Richmond Agitation-Sedation Scale (RASS) is scored from -5 to +4, with -5 being unarousable, 0 being alert and calm, and +4 being combative.
Time frame: Initial 48 postoperative hours or duration of hospitalization (whichever comes first)
Time Spent in Sitting or Upright Position
Treatment effect data are reported as ratios of geometric means
Time frame: Initial 48 postoperative hours or duration of hospitalization (whichever comes first)
Opioid Consumption - Intravenous Morphine Equivalents
Total opioid consumption over the initial 48 postoperative hours was extracted from patients' medical records and converted to intravenous morphine equivalents
Time frame: Initial 48 postoperative hours
Incidence of Postoperative Nausea and Vomiting
Patients were asked about postoperative nausea and vomiting in the postanesthesia care unit, at 4-hour intervals while awake through the remaining initial day of surgery, and on the first and second postoperative mornings.
Time frame: Initial 48 postoperative hours or duration of hospitalization (whichever comes first)
Incidence of Low Respiratory Function Event
A low respiratory function event was defined as an episode of less than 40% of predicted minute ventilation for 2 minutes.
Time frame: Initial 48 postoperative hours or duration of hospitalization (whichever comes first)
Total Anesthetic Dose From Induction to Extubation
Total anesthetic dose is measured in minimal alveolar concentration hours.
Time frame: Induction to extubation (3 hours on average)
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