Airway topicalisation in morbidly obese patients using atomised lidocaine: 2% compared with 4%*

Abstract

SummaryWe evaluated the technique of airway anaesthesia using atomised lidocaine for awake oral fibreoptic intubation in morbidly obese patients using two doses of local anaesthetic. Morbidly obese patients were allocated to receive either 2% or 4% lidocaine (40 ml) for oral airway anaesthesia using an atomiser with high oxygen flow. Patients were carefully sedated using midazolam and fentanyl. Outcomes included patient tolerance to airway manipulation, haemodynamic parameters, and serial plasma lidocaine concentrations. In all, 27 patients were enrolled in the study (2% cohort n = 14, 4% cohort n = 13). Patient characteristics and time for topicalisation and airway management were similar. Haemodynamic parameters did not change significantly. Tolerance to insertion of the Ovassapian airway, bronchoscopy, and tracheal tube positioning was excellent (12 vs 12 patients, 12 vs 12 patients, and 8 vs 12 patients had no response, respectively, 2% vs 4%). Differences did not reach statistical significance. Peak plasma lidocaine concentration was significantly lower in the 2% group (2.8 (0.8) lg.ml )1 compared with 6.5 (1.0) lg.ml

Lidocaine for airway topicalisation

“…We read with interest the recent article by Dr Wieczorek et al on airway topicalisation using 2% and 4% lidocaine in morbidly obese patients prior to fibreoptic intubation [1]. While we agree with the conclusion that the use of atomised lidocaine in these clinical scenarios is a safe and efficacious technique, we do not think that this is fully proven in this study.…”

“…We read with interest the study on airway topicalisation in morbidly obese patients by Wieczorck et al using atomised lidocaine [1]. They state in their method that the lidocaine was delivered via an atomiser but did not include a schematic diagram or photograph to illustrate this equipment or show how it was used.…”

Atomised lidocaine for airway topical anaesthesia in the morbidly obese: 1% compared with 2%*

“…After obtaining written informed consent, patients were randomly assigned (random numbers table) to receive 40 ml of either 1% (400 mg) or 2% (800 mg) lidocaine for airway topicalisation. These doses were based on our previous study [9] showing that superior airway anaesthesia permitting awake oral fibreoptic intubation was achieved with 40 ml of atomised lidocaine 2%. Both the bronchoscopist and an objective observer were blinded to the study medication.…”

“…Oral sodium citrate 30 ml and IV metoclopramide 10 mg and ondansetron 4 mg were given for aspiration prophylaxis, with glycopyrronium 0.3 mg IV for its anti-sialogogue effect. Midazolam (1-2 mg) and fentanyl (100-150 lg) were titrated IV to produce an awake, yet calm and co-operative patient, as previously described [9]. Using high-flow oxygen (10 l.min )1 ), the study drug was administered via a glass atomiser with an adjustable tip (DV-15-RD; Sunrise Medical, Montreal, QC, Canada) to the oropharynx, with the patient breathing deeply through the mouth, and with the nares clamped.…”

“…Recently, we demonstrated that atomised lidocaine 2% or 4% is an efficacious, rapid and safe method to achieve topical airway anaesthesia in morbidly obese patients. However, the lowest optimum dose was not established [9]. This study was undertaken to compare atomised lidocaine 1% and 2% for airway anaesthesia during awake fibreoptic intubation in morbidly obese patients undergoing bariatric surgery.…”