Effect of intravenous acetaminophen on post-anesthesia care unit length of stay, opioid consumption, pain, and analgesics drug costs after ambulatory surgery

Introduction: In the ambulatory surgery setting intravenous APAP has some unique properties that make it an appealing adjunctive agent. It has been theorized that the use of a single post-operative dose of intravenous APAP would enable earlier recovery, which would facilitate an earlier discharge home after ambulatory surgery. 

Objectives: The primary objective was to assess if intravenous acetaminophen (APAP) use in the ambulatory surgery setting is associated with a decreased length of stay in the post-anesthesia care unit (PACU).  The secondary outcomes evaluated were pain scores and opioid consumption.

Study Design: This was a retrospective cohort study conducted in adult patients (age ≥18) who received an eye, ear, nose, or throat (EENT) procedure at an outpatient surgery center between January 2014 and January 2015. 

Methods: Patients were consecutively included until the desired sample was reached during two 6-month time periods: 1) intravenous APAP available on the formulary (APAP group), and 2) intravenous APAP not available on the formulary (non-APAP group).

Results: The cohort included 174 patients who received an EENT procedure (87 patients in APAP group and 87 patients in the non-APAP group). The median PACU length of stay was 66 min (IQR 48 to 92 min) in the APAP group and 71 min (IQR 52 to 89 min) in the non-APAP group (p=0.269).  Mean pain score categories in the APAP versus non-APAP group were mild (85% versus 53%, respectively, p<0.001), moderate (13% versus 33%, respectively, p=0.002), and severe (2% versus 14%, respectively, p=0.005). The median opioid consumption in morphine equivalents was 9 mg (IQR 5 to 13 mg) in the APAP group and 8 mg (IQR 5 to 12 mg) in the non-APAP group (p=0.081). 

Conclusions: Intravenous APAP use in ambulatory surgery is not associated with decreased PACU length of stay.  However, it may decrease post-operative pain.