Egon G. Hansen

Effect of high perioperative oxygen fraction on surgical site infection and pulmonary complications after abdominal surgery: the PROXI randomized clinical trial.

CONTEXT Use of 80% oxygen during surgery has been suggested to reduce the risk of surgical wound infections, but this effect has not been consistently identified. The effect of 80% oxygen on pulmonary complications has not been well defined. OBJECTIVE To assess whether use of 80% oxygen reduces the frequency of surgical site infection without increasing the frequency of pulmonary complications in patients undergoing abdominal surgery. DESIGN, SETTING, AND PATIENTS The PROXI trial, a patient- and observer-blinded randomized clinical trial conducted in 14 Danish hospitals between October 2006 and October 2008 among 1400 patients undergoing acute or elective laparotomy. INTERVENTIONS Patients were randomly assigned to receive either 80% or 30% oxygen during and for 2 hours after surgery. MAIN OUTCOME MEASURES Surgical site infection within 14 days, defined according to the Centers for Disease Control and Prevention. Secondary outcomes included atelectasis, pneumonia, respiratory failure, and mortality. RESULTS Surgical site infection occurred in 131 of 685 patients (19.1%) assigned to receive 80% oxygen vs 141 of 701 (20.1%) assigned to receive 30% oxygen (odds ratio [OR], 0.94; 95% confidence interval [CI], 0.72-1.22; P = .64). Atelectasis occurred in 54 of 685 patients (7.9%) assigned to receive 80% oxygen vs 50 of 701 (7.1%) assigned to receive 30% oxygen (OR, 1.11; 95% CI, 0.75-1.66; P = .60), pneumonia in 41 (6.0%) vs 44 (6.3%) (OR, 0.95; 95% CI, 0.61-1.48; P = .82), respiratory failure in 38 (5.5%) vs 31 (4.4%) (OR, 1.27; 95% CI, 0.78-2.07; P = .34), and mortality within 30 days in 30 (4.4%) vs 20 (2.9%) (OR, 1.56; 95% CI, 0.88-2.77; P = .13). CONCLUSION Administration of 80% oxygen compared with 30% oxygen did not result in a difference in risk of surgical site infection after abdominal surgery. TRIAL REGISTRATION clinicaltrials.gov Identifier: NCT00364741.

The Beneficial Effect of Transversus Abdominis Plane Block After Laparoscopic Cholecystectomy in Day-Case Surgery: A Randomized Clinical Trial

BACKGROUND: Laparoscopic cholecystectomy is associated with postoperative pain of moderate intensity in the early postoperative period. Recent randomized trials have demonstrated the efficacy of transversus abdominis plane (TAP) block in providing postoperative analgesia after abdominal surgery. We hypothesized that a TAP block may reduce pain while coughing and at rest for the first 24 postoperative hours, opioid consumption, and opioid side effects in patients undergoing laparoscopic cholecystectomy in day-case surgery. METHODS: In this randomized, double-blind study, 80 patients undergoing laparoscopic cholecystectomy in our day-case surgery unit were allocated to receive either bilateral ultrasound-guided posterior TAP blocks (20 mL 0.5% ropivacaine) or placebo blocks. Postoperative pain treatment consisted of oral acetaminophen 1000 mg × 4, oral ibuprofen 400 mg × 3, IV morphine (0–2 hours postoperatively), and oral ketobemidone (2–24 hours postoperatively). The primary outcome was postoperative pain scores while coughing calculated as area under the curve for the first 24 postoperative hours (AUC/24 h). Secondary outcomes were pain scores at rest (AUC/24 h), opioid consumption, and side effects. Patients were assessed 0, 2, 4, 6, 8, and 24 hours postoperatively. Group-wise comparisons of visual analog scale (VAS) pain (AUC/24 h) were performed with the 2-sample t test. Morphine and ketobemidone consumption were compared with the Mann-Whitney test for unpaired data. Categorical data were analyzed using the &khgr;2 test. RESULTS: The primary outcome variable, VAS pain scores while coughing (AUC/24 h), was significantly reduced in the TAP versus the placebo group (P = 0.04); group TAP: 26 mm (SD 13) (weighted average level) versus group placebo: 34 (18) (95% confidence interval): 0.5–15 mm). VAS pain scores at rest (AUC/24 h) showed no significant difference between groups. Median morphine consumption (0–2 hours postoperatively) was 7.5 mg (interquartile range: 5–10 mg) in the placebo group compared with 5 mg (interquartile range: 0–5 mg) in the TAP group (P < 0.001). The odds ratio of a random patient in group TAP having less morphine consumption than a random patient in group placebo was P (group TAP < group placebo) = 0.26 (confidence interval: 0.15, 0.37) where 0.5 represents no difference between groups. There were no between-group differences in total ketobemidone consumption, levels of nausea and sedation, number of patients vomiting, or consumption of ondansetron. CONCLUSIONS: TAP block after laparoscopic cholecystectomy may have some beneficial effect in reducing pain while coughing and on opioid requirements, but this effect is probably rather small.

The effect of transversus abdominis plane block or local anaesthetic infiltration in inguinal hernia repair: a randomised clinical trial.

CONTEXT The analgesic effect of transversus abdominis plane (TAP) block after inguinal hernia repair is unclear. OBJECTIVE The aim of this randomised and double-blind study was to evaluate the analgesic effect of a TAP block in patients scheduled for primary inguinal hernia repair. The TAP block was evaluated versus placebo and versus an active comparator (ilioinguinal block and wound infiltration). DESIGN Randomised controlled trial. SETTING Single centre trial. Study period from June 2010 to November 2011. PATIENTS Adults (18 to 75 years) with American Society of Anesthesiologists’ status 1–3 scheduled for primary inguinal hernia repair as day case surgery were included in the study. INTERVENTIONS Ninety patients were allocated to one of three groups: group TAP, group infiltration (ilioinguinal nerve block and wound infiltration) and group placebo. MAIN OUTCOME MEASURES The primary outcome measure was pain scores while coughing between group TAP and group placebo calculated as area under the curve for the first 24 h (AUC24 h). Secondary outcomes were pain scores while coughing and at rest, opioid consumption and side effects in groups TAP, infiltration and placebo. RESULTS Visual analogue pain scores while coughing and at rest demonstrated no difference between groups. Pain scores in groups infiltration, TAP and placebo were 19 versus 22 versus 15 mm at rest (P = 1.00) and 37 versus 41 versus 37 mm while coughing (P = 1.00). Pain scores at 6 h (AUC6 h) were significantly lower in group infiltration than in group TAP (10 versus 25 mm at rest, P < 0.001; 17 versus 40 mm while coughing, P < 0.001), and than in group placebo (10 versus 20 mm at rest, P = 0.003; 17 versus 38 mm while coughing, P < 0.001). Median morphine consumption was lower in group infiltration than in group placebo (0 versus 5 mg, P < 0.003). No differences among groups were demonstrated for ketobemidone consumption or side effects. CONCLUSION Ultrasound-guided TAP block did not reduce postoperative pain after inguinal hernia repair. TRIAL REGISTRATION Clinicaltrials.gov identifier: NCT01052285. EudraCT number 2010–018403-29.

Potentially toxic concentrations in blood of total ropivacaine after bilateral transversus abdominis plane blocks; a pharmacokinetic study.

Context Elevated blood levels of lidocaine and ropivacaine have been described after transversus abdominis plane (TAP) block. Objective To investigate the pharmacokinetic profile of ropivacaine after bilateral TAP blocks. Design Prospective observational pharmacokinetic study. Setting University teaching hospital in Copenhagen, Denmark. Patients Twenty-one adult patients presenting for abdominopelvic surgery with bilateral TAP blocks were enrolled. Procedures Ultrasound-guided TAP blocks with bilateral injections of 20 ml ropivacaine 0.5% w/v (total dose 200 mg). Blood was sampled at 0, 10, 30 and 60 min after TAP blocks. Measures Total and free peak blood concentrations (Cmax) of ropivacaine. Results Data were analysed from N = 18 patients. The median dose of ropivacaine was 2.7 mg kg−1 (range: 1.9–4.2 mg kg−1). Median total ropivacaine concentrations were 1.0, 1.6 and 1.7 &mgr;g ml−1 at 10, 30 and 60 min, respectively. Six patients (33%) had Cmax values above 2.2 &mgr;g ml−1 and the highest concentration measured was 5.1 &mgr;g ml−1. One patient had a 33% drop in mean arterial blood pressure. Conclusion TAP blocks with bilateral injections of 20 ml ropivacaine 0.5% w/v gave rise to potentially toxic peak blood concentrations of total ropivacaine in one-third of the patients.

Intubation conditions after rocuronium or succinylcholine for rapid sequence induction with alfentanil and propofol in the emergency patient.

Background and objective: Previous studies mainly conducted on elective patients recommend doses of 0.9‐1.2 mg kg−1 rocuronium to obtain comparable intubation conditions with succinylcholine 1.0 mg kg−1 after 60 s during a rapid‐sequence induction. We decided to compare the overall intubating conditions of standard doses of rocuronium 0.6 mg kg−1 and succinylcholine 1.0 mg kg−1 during a strict rapid‐sequence induction regimen including propofol and alfentanil. Methods: Male and female patients (ASA I‐III) older than 17 yr scheduled for emergency abdominal or gynaecological surgery and with increased risk of pulmonary aspiration of gastric content were randomized to a rapid‐sequence induction with succinylcholine 1.0 mg kg−1 or rocuronium 0.6 mg kg−1. Patients with a predicted difficult airway were excluded. A senior anaesthesiologist ‘blinded’ for the randomization performed the intubation 60 s after injection of the neuromuscular blocker. Intubating conditions were evaluated according to an established guideline. Tracheal intubation not completed within 30 s was recorded as failed. Results: 222 patients were randomized. Three patients had their operation cancelled and 10 did not fulfil the inclusion criteria. Clinically acceptable intubation conditions were present in 93.5% and 96.1% of patients in the succinylcholine group (n = 107) and the rocuronium group (n = 102), respectively (P = 0.59). Conclusions: During a rapid‐sequence induction with alfentanil and propofol, both rocuronium 0.6 mg kg−1 and succinylcholine 1.0 mg kg−1 provide clinically acceptable intubation conditions in 60 s in patients scheduled for emergency surgery. Under the conditions of this rapid‐sequence induction regimen rocuronium may be a substitute for succinylcholine.

PaO2 during anaesthesia and years of smoking predict late postoperative hypoxaemia and complications after upper abdominal surgery in patients without preoperative cardiopulmonary dysfunction

Background: The incidence of late postoperative hypoxaemia and complications after upper abdominal surgery is 20–50% among cardiopulmonary healthy patients. Atelectasis development during anaesthesia and surgery is the main hypothesis to explain postoperative hypoxaemia. This study tested the predictive value of PaO2<19 kPa during combined general and thoracic epidural anaesthesia and the preoperative functional residual capacity (FRC) reduction in the 30° head tilt‐down position for the development of late prolonged postoperative hypoxaemia, PaO2<8.5 kPa for a minimum of 3 out of 4 days, and other complications.

Transversus abdominis plane (TAP) block after robot‐assisted laparoscopic hysterectomy: a randomised clinical trial

Transversus abdominis plane (TAP) block is widely used as a part of pain management after various abdominal surgeries. We evaluated the effect of TAP block as an add‐on to the routine analgesic regimen in patients undergoing robot‐assisted laparoscopic hysterectomy.

Resuscitation by hyperbaric exposure from a venous gas emboli following laparoscopic surgery.

Venous gas embolism is common after laparoscopic surgery but is only rarely of clinical relevance. We present a 52 year old woman undergoing laparoscopic treatment for liver cysts, who also underwent cholecystectomy. She was successfully extubated. However, after a few minutes she developed cardiac arrest due to a venous carbon dioxide (CO2) embolism as identified by transthoracic echocardiography and aspiration of approximately 7 ml of gas from a central venous catheter. She was resuscitated and subsequently treated with hyperbaric oxygen to reduce the size of remaining gas bubbles. Subsequently the patient developed one more episode of cardiac arrest but still made a full recovery. The courses of events indicate that bubbles had persisted in the circulation for a prolonged period. We speculate whether insufficient CO2 flushing of the laparoscopic tubing, causing air to enter the peritoneal cavity, could have contributed to the formation of the intravascular gas emboli. We conclude that persistent resuscitation followed by hyperbaric oxygen treatment after venous gas emboli contributed to the elimination of intravascular bubbles and the favourable outcome for the patient.

Effect of intermediate care on mortality following emergency abdominal surgery. The InCare trial: study protocol, rationale and feasibility of a randomised multicentre trial

BackgroundEmergency abdominal surgery carries a 15% to 20% short-term mortality rate. Postoperative medical complications are strongly associated with increased mortality. Recent research suggests that timely recognition and effective management of complications may reduce mortality. The aim of the present trial is to evaluate the effect of postoperative intermediate care following emergency major abdominal surgery in high-risk patients.Methods and designThe InCare trial is a randomised, parallel-group, non-blinded clinical trial with 1:1 allocation. Patients undergoing emergency laparotomy or laparoscopic surgery with a perioperative Acute Physiology and Chronic Health Evaluation II score of 10 or above, who are ready to be transferred to the surgical ward within 24 h of surgery are allocated to either intermediate care for 48 h, or surgical ward care. The primary outcome measure is all-cause 30-day mortality. We aim to enrol 400 patients in seven Danish hospitals. The sample size allows us to detect or refute a 34% relative risk reduction of mortality with 80% power.DiscussionThis trial evaluates the benefits and possible harm of intermediate care. The results may potentially influence the survival of many high-risk surgical patients. As a pioneer trial in the area, it will provide important data on the feasibility of future large-scale randomised clinical trials evaluating different levels of postoperative care.Trial registrationClinicaltrials.gov identifier: NCT01209663

Transversus abdominis plane block after laparoscopic colonic resection in cancer patients: A randomised clinical trial.

BACKGROUNDA key point in pathways for optimal rehabilitation and enhanced recovery is an effective postoperative multimodal pain treatment regimen. OBJECTIVETo investigate the analgesic effects of transversus abdominis plane (TAP) block in conjunction with paracetamol and ibuprofen in patients undergoing laparoscopic colonic resection. DESIGNRandomised placebo-controlled double-blind study. SETTINGHerlev University Hospital, Copenhagen, Denmark, from March 2010 to February 2013. PATIENTSEighty adult patients scheduled for elective laparoscopic colectomy. INTERVENTIONSBilateral TAP block with 20 ml of either ropivacaine or isotonic saline. MAIN OUTCOME MEASURESVisual analogue scale (VAS) pain scores (0 to 100 mm) while coughing at 6 h after surgery (primary outcome). Secondary outcomes were area under the curve pain scores (2 to 24 h) at rest and while coughing, 24-h morphine consumption and incidence of nausea and vomiting. RESULTSVAS pain scores at 6 h while coughing was not different between groups (median, interquartile range), TAP, 27 (11 to 45) mm vs. placebo, 33 (20 to 49) mm (P = 0.20). Total 24-h morphine consumption was reduced in the TAP block group vs. placebo group, 30 (15 to 41) mg vs. 43 (30 to 67) mg, respectively (P = 0.008). This difference was most pronounced in the first postoperative hours. The remaining outcomes did not differ between groups. CONCLUSIONTAP block used in combination with paracetamol and ibuprofen did not reduce pain after laparoscopic colonic surgery. However, we found a 30% reduction in opioid use, most marked in the early postoperative period. TRIAL REGISTRATIONwww.clinicaltrials.gov (NCT01418144).