The median effective analgesic dose (ED50) of ropivacaine in ultrasound-guided transversus abdominis plane block for analgesia in reversal of ileostomy: A double-blind up-down dose-finding study.

BACKGROUND: The transversus abdominis plane block has become popular since it has been combined with ultrasound-guided techniques. In abdominal surgery, and especially in subumbilical surgery, it improves postoperative analgesia and reduces morphine consumption. Although it has been shown to be an effective technique, there are wide variations in reported doses and volumes of local anaesthetic used. OBJECTIVE: The primary objective was to assess the median effective analgesic dose (ED50 = effective dose in 50% of patients) of ropivacaine in TAP blocks for patients undergoing reversal of ileostomy. DESIGN: A double-blind up-down dose-finding study. SETTING: French Teaching Hospital. PATIENTS: Twenty-six colorectal patients were included. INTERVENTIONS: After standardised general anaesthesia, a unilateral ultrasound-guided TAP block was performed on patients undergoing elective reversal of ileostomy using 20 ml of ropivacaine. Doses were predefined according to the up-and-down method. The first patient received a dose of 1.6 mg kg(-1). The dose adjustment interval was 0.2 ml kg(-1). The potentially toxic dose of 3 mg kg(-1) was never exceeded. MAIN OUTCOME MEASURE: The primary endpoint was pain (defined as 3 or higher on a numerical pain scale of 0 to 10) at rest 6 h after TAP block. RESULTS: Out of the twenty-six patients who were included in the study, the ED50 of ropivacaine in TAP block for patients undergoing reversal of ileostomy was 2.70 mg kg(-1) [95% confidence interval (95% CI) 2.37 to 3.03 mg kg(-1)]. CONCLUSION: The ED50 of ropivacaine in TAP blocks in reversal of ileostomy is close to the toxic threshold. Anaesthesiologists should always be aware of the systemic toxicity risk and use weight-based doses when performing a TAP block.

Comparison of plastic and metallic single-use and metallic reusable laryngoscope blades: a randomised controlled trial.

CONTEXT: Plastic single-use laryngoscope blades have been found to increase the difficulty of intubation. Metallic single-use blades may represent an alternative. OBJECTIVE: To compare the rates of intubation failure at first laryngoscopy using metallic single-use, plastic single-use and metallic reusable laryngoscope blades. DESIGN: Randomised, superiority, single-centre, controlled trial. SETTING: Operating theatres at a University Hospital from January 2008 to August 2009. PATIENTS: A total of 1863 adults requiring general anaesthesia. INTERVENTION: Patients were randomised to one of three laryngoscope blades: metallic single-use, plastic single-use or metallic reusable. MAIN OUTCOME MEASURE: The primary end-point was the number of intubation failures at first laryngoscopy. Secondary end-points were glottic exposure and the Intubation Difficulty Scale. RESULTS: The failure rate (absolute difference: 95% confidence interval) at the first attempt was greater for the plastic single-use blades (8.1%) than for the metallic reusable [3.2% (4.9%: 2.2 to 7.6%); P < 0.001] and metallic reusable blades [4.0% (4.0%: 1.2 to 6.9%); P < 0.006]. No difference was found between the metallic reusable and metallic single-use groups (0.9%: -1.3 to 3.1%). Scoring on the Intubation Difficulty Scale [median (interquartile range)] was higher in the plastic single-use group [1 (0 to 2)] than in the metallic groups [metallic reusable: 0 (0 to 1); P < 0.001 and metallic single-use: 0 (0 to 1); P < 0.007] groups. Glottic exposure was significantly better in the metallic reusable group (modified Cormack & Lehane score III and IV: 3.7%) compared with the plastic single-use group (modified Cormack & Lehane score III and IV: 9.4%; P < 0.03). CONCLUSION: The rates of failed intubation at first laryngoscopy were similar in the metallic reusable and metallic reusable groups, but greater in the plastic single-use group.