Background: Pain after coronary artery bypass surgery persists for several days. A continuous intravenous infusion of an opioid adequately accomplishes good pain control in the intensive care unit, but it is often not suitable on the ordinary ward. Patient-controlled analgesia (PCA) with intermittent injections delivered by one of the new devices now available could be an alternative to conventional nurse-controlled analgesia (NCA) based on intermittent injections. The aim was to compare these two techniques with respect to efficacy and the amount of opioid used.

Methods: Forty-eight patients randomly received PCA or NCA with ketobemidone following extubation after coronary artery bypass grafting. Drug consumption, pain assessment with the visual analogue score (VAS) and possible side effects were evaluated from extubation to the end of the second postoperative day.

Results: On the day of surgery the VAS scores did not differ between the groups. From the afternoon of the first postoperative day the VAS scores were higher in the NCA group with mean values at 3–4 out of 10 as compared with mean values around 2 in the PCA group (P<0.01). During the study period the patients in the PCA group received more ketobemidone as compared with the NCA group, 61.9±24.0 mg and 36.3±20.2 mg, respectively (P<0.01). Additional oral analgesics were used in 12 of the patients in the NCA group compared with none in the PCA group. The few side effects reported were equally distributed between the two groups.

Conclusion: PCA treatment after coronary artery bypass surgery resulted in better pain treatment and the use of more opioid without an increase in side effects compared with traditional NCA treatment.

Objective: To investigate if early extubation, 2 hours after surgery, would result in more postoperative pain or in an increased use of opioid analgesics compared with late extubation, 6 hours after surgery.

Design: Prospective, randomized study.

Setting: Intensive care unit, university hospital.

Participants: Sixty patients undergoing cardiac surgery with cardiopulmonary bypass.

Interventions: Patients were randomized into 2 groups: extubation at about 2 (early) or 6 (late) hours. Anesthesia was based on propofol and remifentanil. There was no epidural analgesia and no local anesthesia in the wound. A bolus of the opioid ketobemidone was administered toward the end of surgery followed by a continuous infusion.

Measurements and Main Results: Pain, provoked during deep breathing or coughing, evaluated with a visual analog scale (VAS) going from 0 to 10, was measured after extubation, and at 8 and 16 hours after surgery. Unprovoked pain was measured hourly. If VAS was greater than 3, the infusion rate was increased and a bolus of ketobemidone was given. Three patients in the late group were excluded because of incomplete data. Pain did not differ between the early and late groups at any time. In all patients, 21 never scored >3, 11 scored >3 once, and 25 scored >3 more than once. Nine patients had 1 score >5. The amount of ketobemidone was similar in both groups.

Conclusions: Early extubation had no negative effect on the quality of postoperative pain control and was not followed by an increased use of analgesics.

Background:  Paracetamol is a peripherally acting analgesic commonly used in multimodal post-operative pain management to reduce the need for more potent analgesics with their unwanted side-effects. The dose and optimal galenical form for achieving analgesic concentrations is not well defined. The primary aim of this pilot project was to study the early bioavailability for two fixed doses of orally administrated paracetamol and one dose of intravenous propacetamol, all of which were given after minor surgery.

Methods:  Thirty-five patients undergoing day surgery were divided into five groups, seven patients each. Groups received either 1 g of an ordinary paracetamol tablet, 2 g of an ordinary paracetamol tablet, 1 g of a bicarbonate paracetamol tablet, 2 g of a bicarbonate paracetamol tablet or 2 g intravenously of prodrug propacetamol. We studied the plasma concentration of paracetamol during the first 80 min after administration.

Results:  Within 40 min, intravenous propacetamol gave a median plasma paracetamol concentration of 85 µmol/l (range 65–161) and decreased thereafter. After oral administration, median plasma paracetamol concentration increased with increasing dose and time, but there were huge inter-individual differences at all time points studied. At 80 min after oral paracetamol the median plasma concentrations were 36 and 129 µmol/l for the 1- and 2-g groups, respectively, with an overall range between 0 and 306 µmol/l.

Conclusion:  Oral administration of paracetamol as part of multimodal pain management immediately post-operatively resulted in a huge and unpredictable variation in plasma concentration compared with the intravenous administration.

Background:  Paracetamol is commonly used for post-operative pain management in combination with more potent analgesics. The best route of paracetamol administration after major surgery, when oral intake may not be optimal, is not known. Our primary purpose was to study plasma concentrations after the 1st and 4th dose of 1 g of paracetamol given either rectally or intravenously (i.v.) after major surgery.

Methods:  In this prospective, randomized study, 48 patients undergoing heart surgery were randomized upon arrival to the intensive care unit (ICU) to receive paracetamol every 6th hour either as suppositories or intravenous injections. In half the patients (n= 24), blood samples for paracetamol concentration were obtained before and 20, 40 and 80 min after the first dose. In the other patients (n= 24), additional samples were taken prior to, and at 20, 40, 80 min and 4 and 6 h after, the 4th dose.

Results:  Plasma paracetamol concentration peaked (95 ± 36 μmol/l) within 40 min after initial i.v. administration but did not increase within 80 min after the 1st suppository. Plasma concentration before the 4th dose was 74 ± 51 and 50 ± 27 in the rectal and i.v. groups, respectively. Paracetamol concentration peaked 20 min after the 4th dose for the i.v. patients (210 ± 84 μmol/l) and declined to 99 ± 27 μmol/l at 80 min as compared with the rectal patients 69 ± 44 to 77 ± 48 μmol/l.

Conclusion:  Both time course and peak plasma concentrations of paracetamol given rectally differ from the one seen after intravenous administration. The clinical impact of these differences needs further investigation.

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 opioid-sparing effect was not accompanied by any reduction in the incidence of PONV. The clinical significance of the opioid-sparing effect could therefore be questioned.