Intravenous acetaminophen reduced the use of opioids compared with oral administration after coronary artery bypass grafting

Objective: The purpose of this study was to evaluate if intravenous acetaminophen compared to oral administration reduced the consumption of opioids and their side effects without an increase in pain during the stay in the intensive care unit (ICU). Design: Prospective, randomized study. Setting: An ICU in a university hospital. Participants: Eighty patients with written informed consent undergoing coronary artery bypass grafting with cardiopulmonary bypass. Anesthesia was based on propofol and fentanyl combined with sevoflurane. Interventions: Patients were randomized to 2 groups: acetaminophen, 1 g every sixth hour during the postoperative period, either as tablets or intravenously after extubation. Measurements and Main Results: The amount of opioids administered during the study period was measured starting with acetaminophen administration during the stay in the ICU until 9 o'clock the following morning. Incidence of postoperative nausea and vomiting (PONV) was noted. Pain was evaluated with a visual analog scale (VAS) from 0 to 10. Three patients, 2 in the oral and 1 in the intravenous group, were excluded because of incomplete data. The intravenous group received less opioids than the orally treated group, 17.4 +/- 7.9 mg compared with 22.1 +/- 8.6 mg (p = 0.016). PONV incidence and VAS scores did not differ. During the first hours after extubation, 50 of 77 patients reported VAS scores > 3 with no difference between groups. Conclusions: Intravenous acetaminophen had a limited opioid-sparing effect when compared with oral administration after coronary artery bypass graft surgery. The opioidsparing effect was not accompanied by any reduction in the incidence of PONV. The clinical significance of the opioidsparing effect could therefore be questioned. (c) 2005 Elsevier Inc. All rights reserved.