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The ability to combine and use drugs in a single infusion device may be useful in resource-limited settings. This study examined the chemical stability of an opioid-sparing mixture of ketamine, lidocaine and magnesium sulphate when combined in a single syringe. High-performance liquid chromatography and atomic absorption spectrophotometry were performed on six syringes containing the three-drug mixture. Since most opioid-sparing techniques typically rely on a 24-hour infusion regime, we tested stability at the initial admixing and 24 hours later. Stability was defined as a measured drug concentration within 10% of expected, with the absence of precipitation or pH alterations. Pharmacokinetic simulations were conducted to further show that the achieved plasma drug concentrations were well within an effective analgesic range. All mixed drug concentration measurements were within the required 10% reference limit. No obvious precipitation or interaction occurred, and pH remained stable. Drug stability was maintained for 24 hours. Pharmacokinetic simulations showed that ketamine and lidocaine were within their minimum analgesic effect concentrations. Our results show that this three-drug mixture is chemically stable for up to 24 hours after mixing, with a pharmacokinetic simulation illustrating safe, clinically useful predicted plasma concentrations when using the described admixture. [ABSTRACT FROM AUTHOR]

Summary: Chronic postoperative pain is common after breast cancer surgery. Peri‐operative lidocaine infusion may prevent the development of chronic postoperative pain, but a large‐scale trial is required to test this hypothesis. It is unclear whether a pragmatic, multicentre trial design that is consistent with expert guidance, addresses the limitations of previous studies, and overcomes existing translational barriers is safe, effective and feasible. We conducted a double‐blind, randomised controlled pilot study in 150 patients undergoing breast cancer surgery across three hospitals in Western Australia. Patients received lidocaine, or equivalent volumes of saline, as an intravenous bolus (1.5 mg.kg‐1) and infusion (2 mg.kg‐1.h‐1) intra‐operatively, and a subcutaneous infusion (1.33 mg.kg‐1.h‐1) postoperatively for up to 12 h on a standard surgical ward, with novel safety monitoring tools in place. The co‐primary outcomes were: in‐hospital safety events; serum levels of lidocaine during intravenous and subcutaneous infusion; and annualised enrolment rates per site with long‐term data capture. In‐hospital safety events were rare, and similar in the placebo and lidocaine arms (3% vs. 1%). Median (IQR [range]) serum lidocaine levels during intravenous (2.16 (1.74–2.83 [1.12–6.06]) µg.ml‐1, n = 41) and subcutaneous (1.52 (1.28–1.83 [0.64–2.85]) µg.ml‐1, n = 48) infusion were comparable with previous trials reporting improved pain outcomes. Annualised enrolment approximated 50 patients per site per year, with high levels of protocol adherence and ≥ 99% capture of outcomes at 3 and 6 months. The adjusted odds ratio (95%CI) for postoperative pain at 6 months in the lidocaine arm was 0.790 (0.370–1.684). We conclude that this trial, as designed, is safe, effective and feasible in patients undergoing breast cancer surgery, and a larger‐scale trial is planned. [ABSTRACT FROM AUTHOR]

Unlicensed intravenous lidocaine for postoperative pain: always a safer "licence to stop" than to start Keywords: critical incident; lidocaine; pain; postoperative; safety EN critical incident lidocaine pain postoperative safety 156 160 5 01/15/21 20210201 NES 210201 The Safe Anaesthesia Liaison Group (SALG) became aware of patient harm and near-misses after use of intravenous (i.v.) lidocaine administered for pain relief in the peri-operative setting in 2019 [1]. Issues raised by using i.v. lidocaine as an unlicensed medicine Doctors have always used unlicensed medications for patient benefit. This includes, for example, the mixing of drugs (e.g. lidocaine with propofol to reduce pain on injection) [18], plain bupivacaine for intrathecal injection [19] and i.v. dexamethasone for postoperative nausea and vomiting (PONV). [Extracted from the article]

Summary: Intravenous lidocaine is used widely for its effect on postoperative pain and recovery but it can be, and has been, fatal when used inappropriately and incorrectly. The risk‐benefit ratio of i.v. lidocaine varies with type of surgery and with patient factors such as comorbidity (including pre‐existing chronic pain). This consensus statement aims to address three questions. First, does i.v. lidocaine effectively reduce postoperative pain and facilitate recovery? Second, is i.v. lidocaine safe? Third, does the fact that i.v. lidocaine is not licensed for this indication affect its use? We suggest that i.v. lidocaine should be regarded as a 'high‐risk' medicine. Individual anaesthetists may feel that, in selected patients, i.v. lidocaine may be beneficial as part of a multimodal peri‐operative pain management strategy. This approach should be approved by hospital medication governance systems, and the individual clinical decision should be made with properly informed consent from the patient concerned. If i.v. lidocaine is used, we recommend an initial dose of no more than 1.5 mg.kg‐1, calculated using the patient's ideal body weight and given as an infusion over 10 min. Thereafter, an infusion of no more than 1.5 mg.kg‐1.h‐1 for no longer than 24 h is recommended, subject to review and re‐assessment. Intravenous lidocaine should not be used at the same time as, or within the period of action of, other local anaesthetic interventions. This includes not starting i.v. lidocaine within 4 h after any nerve block, and not performing any nerve block until 4 h after discontinuing an i.v. lidocaine infusion. [ABSTRACT FROM AUTHOR]

Summary: Peri‐operative lidocaine infusion warrants investigation in bariatric surgery because obese patients present different physiological and pharmacological risks. This single‐centre, prospective, randomised double‐blind placebo‐controlled study enrolled obese patients scheduled for laparoscopic bariatric surgery using an enhanced recovery protocol. Patients received either lidocaine (bolus of 1.5 mg.kg−1, then a continuous infusion of 2 mg.kg−1.h−1 until the end of the surgery, then 1 mg.kg−1.h−1 for 1 h in the recovery area) or identical volumes and rates of 0.9% saline. The primary outcome was the consumption of the equivalent of oxycodone consumption over the first 3 postoperative days. Secondary outcomes were: postoperative pain; incidence of nausea and vomiting; bowel function recovery; and lengths of stay in the recovery area and in hospital. Plasma concentrations of lidocaine were measured. On the 178 patients recruited, data were analysed from 176. The median (IQR [range]) equivalent intravenous oxycodone consumption was 3.3 mg (0.0–6.0 [0.0–14.5]) and 5.0 mg (3.3–7.0 [3.3–20.0]) in the lidocaine and saline groups, respectively (difference between medians (95%CI): 1.7 (0.6–3.4) mg; p = 0.004). Length of stay in the recovery area, postoperative pain, nausea and vomiting, day of recovery of bowel function, and length of stay in hospital were not different between groups. Mean (SD) lidocaine plasma concentrations were 2.44 (0.70) µg.ml−1 and 1.77 (0.51) µg.ml−1 at the end of surgery and 1 hour after the end of infusion, respectively. Lidocaine infusion during bariatric surgery resulted in a clinically non‐relevant difference in postoperative oxycodone consumption. [ABSTRACT FROM AUTHOR]

We evaluated the effect of adrenaline on human skin microcirculation (nutritive and sub-papillary) and systemic cardiovascular variables after it was added to lidocaine in infraclavicular brachial plexus blocks. Twelve healthy, non-smoking male volunteers were included, each attending two study sessions 2 weeks apart, and they were studied using a crossover design. In both sessions, they received an ultrasound-guided infraclavicular brachial plexus block in the non-dominant arm with 0.4 ml.kg-1 lidocaine, 15 mg.ml-1 with or without adrenaline 5 μg.ml-1 . Microcirculation was assessed by laser Doppler fluxmetry (sub-papillary blood flow), capillary video microscopy (nutritive blood flow) and continuous temperature measurements. Heart rate and arterial pressure were recorded continuously and non-invasively. Median (IQR [range]) sub-papillary blood flow increased substantially 30 min after the brachial plexus block, from 8.5 (4.4-13.5 [2.9-28.2]) to 162.7 (111.0-197.8 [9.5-206.7]) arbitrary units with adrenaline (p = 0.017), and from 6.9 (5.3-28.5 [1.8-42.1] to 133.7 (16.5-216.7 [1.0-445.0] arbitrary units without adrenaline (p = 0.036). Nutritive blood flow (functional capillary density, capillaries.mm-2 , measured at the dorsal side of the hand) decreased in the blocked extremity when adrenaline was used as adjuvant, from median (IQR [range]) 45 (36-52 [26-59]) to 38 (29-41 [26-42]), p = 0.028, whereas no significant change occurred without adrenaline. Median finger skin temperature (°C) increased by 44% (data pooled) with no significant differences between the groups. No significant changes were found in the systemic cardiovascular variables with or without adrenaline. We conclude that lidocaine infraclavicular brachial plexus blocks caused an increase in skin sub-papillary blood flow. The addition of adrenaline produced stronger and longer lasting blocks, but decreased the nutritive blood flow. [ABSTRACT FROM AUTHOR]

For the outcome of rate of intra-operative supplemen-tation, lidocaine 2% plus bicarbonate and ropivacaine 0.75% were superior to 2-chloroprocaine 3%, lidocaine 2%, bupivacaine 0.5% and levobupivacaine 0.5%. In the four trials that evaluated the effect of lidocaine 2% plus bicarbonate, one investigated this mixture in the presence of adrenaline and another with adrenaline and fentanyl. [Extracted from the article]

Animal data have demonstrated increased block duration after local anaesthetic injections in diabetic rat models. Whether the same is true in humans is currently undefined. We, therefore, undertook this prospective cohort study to test the hypothesis that type-2 diabetic patients suffering from diabetic peripheral neuropathy would have increased block duration after ultrasound-guided popliteal sciatic nerve block when compared with patients without neuropathy. Thirty-three type-2 diabetic patients with neuropathy and 23 non-diabetic control patients, scheduled for fore-foot surgery, were included prospectively. All patients received an ultrasound-guided popliteal sciatic nerve block with a 30 ml 1:1 mixture of lidocaine 1% and bupivacaine 0.5%. The primary outcome was time to first opioid request after block procedure. Secondary outcomes included the time to onset of sensory blockade, and pain score at rest on postoperative day 1 (numeric rating scale 0-10). These outcomes were analysed using an accelerated failure time regression model. Patients in the diabetic peripheral neuropathy group had significantly prolonged median (IQR [range]) time to first opioid request (diabetic peripheral neuropathy group 1440 (IQR 1140-1440 [180-1440]) min vs. control group 710 (IQR 420-1200 [150-1440] min, p = 0.0004). Diabetic peripheral neuropathy patients had a time ratio of 1.57 (95%CI 1.10-2.23, p < 0.01), experienced a 59% shorter time to onset of sensory blockade (median time ratio 0.41 (95%CI 0.28-0.59), p < 0.0001) and had lower median (IQR [range]) pain scores at rest on postoperative day 1 (diabetic peripheral neuropathy group 0 (IQR 0-1 [0-5]) vs. control group 3 (IQR 0-5 [0-9]), p = 0.001). In conclusion, after an ultrasound-guided popliteal sciatic nerve block, patients with diabetic peripheral neuropathy demonstrated reduced time to onset of sensory blockade, with increased time to first opioid request when compared with patients without neuropathy. [ABSTRACT FROM AUTHOR]

Avoidance of general anaesthesia for breast surgery may be because of clinical reasons or patient choice. There is emerging evidence that the use of regional anaesthesia and the avoidance of volatile anaesthetics and opioid analgesia may have beneficial effects on oncological outcomes. We conducted a prospective observational case series of 16 breast cancer surgeries performed under thoracic paravertebral plus pectoral nerve block with propofol sedation to demonstrate feasibility of technique, patient acceptability and surgeon satisfaction. Fifteen out of 16 cases were successfully completed under sedation and regional anaesthesia, with one conversion to general anaesthesia. Eleven out of 16 cases required low-dose intra-operative opioid analgesia. Out of the 15 surgical procedures completed under regional anaesthesia with sedation, all patients experienced either no or minimal intra-operative pain, and all would choose this anaesthetic technique again. Surgeon-reported operating conditions were 'indistinguishable from general anaesthesia' in most cases, and surgeons were 'extremely satisfied' or 'satisfied' with the technique after every procedure. Combined thoracic paravertebral plus pectoral nerve block with intra-operative sedation is a feasible technique for breast surgery. [ABSTRACT FROM AUTHOR]

We studied the effects of tracheal tube cuffs filled with air, saline or alkalinised lidocaine on haemodynamic changes during tracheal extubation and postoperative laryngotracheal morbidity in children. We randomly allocated 164 children aged 3-13 years undergoing general anaesthesia to one of four groups; tracheal tube cuffs filled with air (n = 41); saline (n = 41); alkalinised lidocaine 0.5% (n = 41); or alkalinised lidocaine 1% (n = 41). Intracuff pressure was monitored and maintained below 20 cmH2 O. The mean (SD) increases in systolic blood pressure after tracheal extubation compared with before extubation were 10.9 (10.8) mmHg, 7.3 (17.7) mmHg, 4.1 (10.5) mmHg and 1.9 (9.5) mmHg in the air, saline, 0.5% and 1% alkalinised lidocaine groups, respectively (p = 0.021). The mean (SD) increases in diastolic blood pressure after tracheal extubation compared with before extubation were 3.9 (9.7) mmHg, 7.9 (14.6) mmHg, 0.7 (10.4) mmHg and 3.6 (6.9) mmHg in the air, saline, 0.5% and 1% alkalinised lidocaine groups, respectively (p = 0.019). The mean (SD) increases in heart rate after tracheal extubation compared with before extubation were 14.2 (7.6) beats.min-1 , 15.5 (13.1) beats.min-1 , 5.2 (9.6) beats.min-1 and 4.1 (6.6) beats.min-1 in the air, saline, 0.5% and 1% alkalinised lidocaine groups, respectively (p < 0.001). The incidence of sore throat 8 h after tracheal extubation was 22.0% in the air-filled group, 9.8% in the saline group, 4.9% in the 0.5% alkalinised lidocaine group and 2.4% in the 1% alkalinised lidocaine group, p = 0.015. We conclude that filling the tracheal tube cuff with alkalinised lidocaine-filled reduces the haemodynamic response to tracheal extubation and postoperative laryngotracheal morbidity in children. [ABSTRACT FROM AUTHOR]

Airway management in patients with periglottic tumour is a high-risk procedure with potentially serious consequences. There is no consensus on how best to secure the airway in this group of patients. We conducted a feasibility study of awake tracheal intubation using a King Vision® videolaryngoscope with a channelled blade in a cohort of 25 patients, with a periglottic tumour requiring diagnostic or radical surgery. We used 10% and 4% lidocaine to topicalise the airway and midazolam and remifentanil for sedation. We recorded the success rate, number of attempts, time to obtain glottic view, time to intubation and complications. Twenty-three of the 25 patients (92%, 95%CI 75-98%) were intubated with the awake videolaryngoscope-assisted technique, with 17/23 (74%, 95%CI 54-87%) intubations achieved at the first attempt. Five patients required two and one patient, three attempts at intubation. Two patients (8%, 95%CI 2-25%) could not tolerate the procedure due to inadequate topical anaesthesia. Median (IQR [range]) times to obtain glottic view and to intubate were 19 (17-22 [10-30]) s and 49 (42-71 [33-107]) s, respectively. Traces of blood in the airway were observed in 4/25 (16%, 95%CI 6-35%) patients. Although airway management in this group of patients was expected to be difficult, successful awake intubation with the King Vision videolaryngoscope was achieved in the majority of patients within less than a minute. This study highlights a number of potential advantages of awake videolaryngoscope-assisted intubation over other awake methods of securing the airway in patients with upper airway obstruction due to periglottic mass. [ABSTRACT FROM AUTHOR]

Aerosol-generating procedures are medical interventions considered high risk for transmission of airborne pathogens. Tracheal intubation of anaesthetised patients is not high risk for aerosol generation; however, patients often perform respiratory manoeuvres during awake tracheal intubation which may generate aerosol. To assess the risk, we undertook aerosol monitoring during a series of awake tracheal intubations and nasendoscopies in healthy participants. Sampling was undertaken within an ultraclean operating theatre. Procedures were performed and received by 12 anaesthetic trainees. The upper airway was topically anaesthetised with lidocaine and participants were not sedated. An optical particle sizer continuously sampled aerosol. Passage of the bronchoscope through the vocal cords generated similar peak median (IQR [range]) aerosol concentrations to coughing, 1020 (645-1245 [120-48,948]) vs. 1460 (390-2506 [40-12,280]) particles.l -1 respectively, p = 0.266. Coughs evoked when lidocaine was sprayed on the vocal cords generated 91,700 (41,907-166,774 [390-557,817]) particles.l -1 which was significantly greater than volitional coughs (p < 0.001). For 38 nasendoscopies in 12 participants, the aerosol concentrations were relatively low, 180 (120-525 [0-9552]) particles.l -1 , however, five nasendoscopies generated peak aerosol concentrations greater than a volitional cough. Awake tracheal intubation and nasendoscopy can generate high concentrations of respiratory aerosol. Specific risks are associated with lidocaine spray of the larynx, instrumentation of the vocal cords, procedural coughing and deep breaths. Given the proximity of practitioners to patient-generated aerosol, airborne infection control precautions are appropriate when undertaking awake upper airway endoscopy (including awake tracheal intubation, nasendoscopy and bronchoscopy) if respirable pathogens cannot be confidently excluded., (© 2023 The Authors. Anaesthesia published by John Wiley & Sons Ltd on behalf of Association of Anaesthetists.)

We compared the Enk Fiberoptic Atomizer Set(™) with boluses of topical anaesthesia administered via the working channel during awake fibreoptic tracheal intubation in 96 patients undergoing elective surgery. Patients who received topical anaesthesia via the atomiser, compared with boluses via the fibreoptic scope, reported a better median (IQR [range]) level of comfort: 1 (1-3 [1-10]) vs. 4 (2-6 [1-10]), p < 0.0001; experienced a reduced total number of coughs: 6 (3-10 [0-34]) vs. 11 (6-13 [0-25]), p = 0.0055; and fewer distinct coughing episodes: 7% vs. 27% respectively, p = 0.0133. The atomiser technique was quicker: 5 (3-6 [2-12]) min vs. 6 (5-7 [2-15]) min, p = 0.0009; and required less topical lidocaine: 100 mg (100-100 [80-160]) vs. 200 mg (200-200 [200-200]), p < 0.0001. Four weeks after nasal intubation, the incidence of nasal pain was less in the atomiser group compared with the control group (8% vs. 50%, p = 0.0015). We conclude that the atomiser was superior to bolus application for awake fibreoptic tracheal intubation. [ABSTRACT FROM AUTHOR]

Postoperative sore throat has a reported incidence of up to 62% following general anaesthesia. In adults undergoing tracheal intubation, female sex, younger age, pre-existing lung disease, prolonged duration of anaesthesia and the presence of a blood-stained tracheal tube on extubation are associated with the greatest risk. Tracheal intubation without neuromuscular blockade, use of double-lumen tubes, as well as high tracheal tube cuff pressures may also increase the risk of postoperative sore throat. The expertise of the anaesthetist performing tracheal intubation appears to have no influence on the incidence in adults, although it may in children. In adults, the i-gel(™) supraglottic airway device results in a lower incidence of postoperative sore throat. Cuffed supraglottic airway devices should be inflated sufficiently to obtain an adequate seal and intracuff pressure should be monitored. Children with respiratory tract disease are at increased risk. The use of supraglottic airway devices, oral, rather than nasal, tracheal intubation and cuffed, rather than uncuffed, tracheal tubes have benefit in reducing the incidence of postoperative sore throat in children. Limiting both tracheal tube and supraglottic airway device cuff pressure may also reduce the incidence. [ABSTRACT FROM AUTHOR]

We allocated 76 men scheduled for radical retropubic prostatectomy to peri-operative lidocaine 2% or saline 0.9%: a pre-operative 0.075 ml.kg(-1) intravenous bolus; an intra-operative intravenous infusion at 0.075 ml.kg(-1) .h(-1) ; and 24 hours' postoperative subcutaneous infusion at 0.075 ml.kg(-1) .h(-1) . Lidocaine reduced the postoperative hospital stay by a mean (95% CI) of 1.3 (0.3-2.4) days, p = 0.017, from a mean (SD) of 4.6 (3.2) days with saline. There were no significant differences in pain at rest or on coughing at 24 h. [corrected]. Lidocaine reduced 24-h morphine consumption by a mean (95% CI) of 13.9 (2.2-25.7) mg, p = 0.021, from a mean (SD) of 52.3 (26.9) mg with saline. There were no differences in other outcomes. [ABSTRACT FROM AUTHOR]

The article presents studies for comparing times in clinical studies with a finite ending. Topics include no difference between the saline and lidocaine groups resulted in null hypothesis; study on different doses of dexamethasone in Anaesthesia using the Kaplan–Meier time-to-event curve; and using logistic regression for investigating between treatment and primary outcome.

Patient groups where the risk-benefit balance are tilted towards benefit include patients who are already on high doses of opioids, intolerant of opioids, and those who are at high risk of chronic postoperative pain. The recent Cochrane review suggested greater patient satisfaction and lower opioid consumption in the post-anaesthesia care unit (PACU) after i.v. lidocaine [4]. We would like to thank Dr McKinney [1] for his interest in our safety statement [2], and his thoughtful comments. [Extracted from the article]

The purpose of this meta-analysis was to determine the efficacy of lidocaine in preventing laryngospasm during general anaesthesia in children. An electronic search of six databases was conducted. The Preferred Reporting Items for Systematic Reviews and Meta-analyses ( PRISMA) guidelines were adhered to. We included randomised controlled trials reporting the effects of intravenous and/or topical lidocaine on the incidence of laryngospasm during general anaesthesia. Nine studies including 787 patients were analysed. The combined results demonstrated that lidocaine is effective in preventing laryngospasm (risk ratio ( RR) 0.39, 95% CI 0.24-0.66; I2 = 0). Subgroup analysis revealed that both intravenous lidocaine ( RR 0.34, 95% CI 0.14-0.82) and topical lidocaine ( RR 0.42, 95% CI 0.22-0.80) lidocaine are effective in preventing laryngospasm. The results were not affected by studies with a high risk of bias. We conclude that, both topical and intravenous lidocaine are effective for preventing laryngospasm in children. [ABSTRACT FROM AUTHOR]

Disagreement in this context, given the precarious evidence base, is an entirely reasonable standpoint. An ideal situation would be that all ad hoc use ceased, and instead all patients receiving intravenous lidocaine did so as part of well-designed trials that helped generate the necessary evidence. [Extracted from the article]

Taken together, systemic lidocaine offers a, albeit debatable, clinical benefit when assessed as an isolated drug compared with placebo, but likely adds relevant effects when given in the context of a multimodal pain management approach. Intravenous lidocaine: it's all about a risk-benefit analysis We read with great interest the editorial by Pandit and McGuire [1] and appreciate their critical view on the safety of drugs for postoperative pain control, in particular intravenous (i.v.) lidocaine. [Extracted from the article]

We describe the awake fibreoptic intubation followed by awake prone positioning of a woman weighing 180 kg with body mass index of 62 kg.m−2 requiring emergency lumbar discectomy for cauda equina syndrome. This approach was taken to overcome difficulties in transfering an anaesthetised patient on to the operating table. Following topical anaesthesia with lidocaine and low-dose remifentanil infusion, oral intubation was performed using a split oral airway to guide the fibrescope. The patient positioned herself on the Jackson operating table, following which general anaesthesia was induced. This technique optimised protection of the patient's eyes and other pressure areas while preventing undue cardiorespiratory compromise. The patient tolerated the procedure well, and later confirmed that she would consent to undergoing the same procedure again if further surgery became necessary. [ABSTRACT FROM AUTHOR]

We conducted a randomised trial comparing lidocaine 2% gel with proparacaine 0.5% eye drops in children having elective squint surgery. One hundred and forty children aged between 3 and 14 years were recruited. The requirement for intra-operative fentanyl and postoperative ibuprofen was significantly less in the lidocaine group compared with the proparacaine group (1 (1.7%) vs 12 (18.5%), p = 0.002 and 16 (27.6%) 38 (58.5%), p = 0.001, respectively). The incidence of postoperative nausea and vomiting was significantly less in the lidocaine group compared with the proparacaine group (6 (10.3%) vs 16 (24.6%), p = 0.04). There were no differences between the groups in terms of incidence and severity of the oculocardiac reflex. We conclude that, compared with proparacaine 0.5% eye drops, a single application of lidocaine 2% gel improves peri-operative analgesia and reduces the incidence of postoperative nausea and vomiting in elective paediatric squint surgery. [ABSTRACT FROM AUTHOR]

We studied the effect of intravenous lidocaine on laryngeal and respiratory reflex responses in children anaesthetised with sevoflurane. We tested the hypothesis that the incidence of laryngospasm evoked by laryngeal stimulation is temporarily diminished after the administration of lidocaine. Forty children, aged between 25 and 84 months, were anaesthetised with sevoflurane and breathed spontaneously through a laryngeal mask airway. Respiratory reflex responses were elicited by spraying distilled water onto the laryngeal mucosa at three time intervals: (i) before lidocaine was administered (baseline); (ii) at 2 min and (iii) at 10 min following the intravenous administration of a bolus of lidocaine 2 mg.kg−1. A blinded reviewer assessed the evoked responses. The incidence of laryngospasm was reduced from 38% at baseline to 15% 2 min after lidocaine administration (p < 0.02) and 18% 10 min after lidocaine administration (p = 0.10). We conclude that intravenous lidocaine significantly reduced the incidence of laryngospasm but that the effect was short-lived. [ABSTRACT FROM AUTHOR]

We compared the work needed to retract a non-lubricated and a lubricated stylet from a tracheal tube over 24 h. Stylets were lubricated with sterile water, silicone fluid, lidocaine spray, lidocaine gel, MedPro® lubricating gel or Lacri-Lube®. The mean (SD) work in joules needed to retract the stylet by 5 cm from the tracheal tube was recorded immediately (time 0), at 5 and 30 min and at 1, 3 and 24 h. At time 0 lubrication with sterile water (0.53 (0.09); p = 0.001), silicone fluid (0.43 (0.10); p < 0.001), lidocaine gel (0.60 (0.15); p = 0.01) and MedPro gel (0.57 (0.07); p = 0.005), were better than no lubrication (0.94 (0.28)). Where a tracheal tube is pre-loaded with a stylet for use at an indeterminate time, silicone fluid was the best choice of lubricant as it performed consistently well up to 24 h. At 24 h only silicone fluid (0.49 (0.01)) outperformed no lubrication (0.77 (0.24); p = 0.04). [ABSTRACT FROM AUTHOR]

We present the use of the SensaScope™, an S-shaped rigid fibreoptic scope with a flexible distal end, in a series of 13 patients at high risk of, or known to have, a difficult intubation. Patients received conscious sedation with midazolam or fentanyl combined with a remifentanil infusion and topical lidocaine to the oral mucosa and to the trachea via a trans-cricoid injection. Spontaneous ventilation was maintained until confirmation of tracheal intubation. In all cases, tracheal intubation was achieved using the SensaScope. The median (IQR [range]) insertion time (measured from the time the facemask was taken away from the face until an end-expiratory CO2 reading was visible on the monitor) was 58 s (38–111 [28–300]s). In nine of the 13 cases, advancement of the SensaScope into the trachea was easy. Difficulties included a poor view associated with a bleeding diathesis and saliva, transient loss of spontaneous breathing, and difficulty in advancing the tracheal tube in a patient with unforeseen tracheal narrowing. A poor view in two patients was partially improved by a high continuous flow of oxygen. The SensaScope may be a valuable alternative to other rigid or flexible fibreoptic scopes for awake intubation of spontaneously breathing patients with a predicted difficult airway. [ABSTRACT FROM AUTHOR]

This study investigates the effect of suxamethonium vs rocuronium on the onset of haemoglobin desaturation during apnoea, following rapid sequence induction of anaesthesia. Sixty patients were randomly allocated to one of three groups. Anaesthesia was induced with lidocaine 1.5 mg.kg−1, fentanyl 2 μg.kg−1 and propofol 2 mg.kg−1, followed by either rocuronium 1 mg.kg−1 (Group R) or suxamethonium 1.5 mg.kg−1 (Group S). The third group received propofol 2 mg.kg−1 and suxamethonium 1.5 mg.kg−1 only (Group SO). The median (IQR [range]) time to reach SpO2 of 95% was significantly shorter in Group S (358 (311–373 [215–430]) s) than in Group R (378 (370–393 [366–420]) s; p = 0.003), and shorter in Group SO (242 (225–258 [189–370]) s) than in both Group R (p < 0.001) and Group S (p < 0.001). When suxamethonium is administered for rapid sequence induction of anaesthesia, a faster onset of oxygen desaturation is observed during the subsequent apnoea compared with rocuronium. However, time to desaturation is prolonged whenever lidocaine and fentanyl precede suxamethonium. [ABSTRACT FROM AUTHOR]

Airway anaesthesia using atomised lidocaine for awake oral fibreoptic intubation in morbidly obese patients was evaluated using two doses of local anaesthetic. In this randomised, blinded prospective study, 40 ml of atomised 1% ( n = 11) or 2% ( n = 10) lidocaine was administered with high oxygen flow as carrier. Outcomes included time for intubation, patient tolerance to airway manipulation, haemodynamic parameters, the bronchoscopist’s overall satisfaction, and serial serum lidocaine concentrations. Patients receiving lidocaine 1% had a longer mean (SD) time from the start of topicalisation to tracheal tube cuff inflation than those receiving lidocaine 2% (8.6 (0.9) min vs 6.9 (0.5) min, respectively; p < 0.05). Patients in the 1% cohort demonstrated increased responses to airway manipulation (p < 0.0001), reflecting lower bronchoscopist’s satisfaction scores (p < 0.03). Haemodynamic responses to topicalisation and airway manipulation were similar in both groups. Peak plasma concentration was lower in the 1% group (mean (SD) 1.4 (0.3) and 3.8 (0.5) μg.ml−1, respectively; p < 0.001). Airway anaesthesia using atomised lidocaine for awake oral fibreoptic intubation in the morbidly obese is efficacious, rapid and safe. Compared with lidocaine 1%, the 2% dose provides superior intubating conditions. [ABSTRACT FROM AUTHOR]

This prospective, randomised, observer blinded study compared the onset time of brachial plexus block using 2% lidocaine 25–30 ml with adrenaline 5 μg.ml−1 into the ‘corner pocket’ inferolateral/lateral to the subclavian artery (supraclavicular, n = 30) or to a triple point injection around the axillary artery (infraclavicular, n = 30). Mean (SD) onset time for complete pinprick sensory blockade assessed by a blinded observer in all four distal nerves was similar in both groups: supraclavicular = 22 (9.4) min, infraclavicular = 21 (7.1) min, p = 0.59. Complete sensory blockade in all four nerve territories at 30 min was achieved in 57% in group supraclavicular and 70% in group infraclavicular (p = 0.28). Painless surgery without the requirement for block supplementation was higher in group infraclavicular (28/30, 93%) compared with group supraclavicular (19/30, 67%; p = 0.01). Of the 11 failures in group supraclavicular, nine were due to incomplete ulnar nerve territory anaesthesia. These results do not support the concept of rapid onset successful supraclavicular block via a simple ultrasound-guided local anaesthetic injection inferolateral to the subclavian artery. [ABSTRACT FROM AUTHOR]

We studied 21 patients with known difficult airways who underwent awake tracheal intubation using the LMA CTrach™. Patients were given midazolam, atropine, a continuous infusion of remifentanil and topical lidocaine applied to the oropharyx. We limited the number of insertion attempts to three and the time to adjust the view to 5 min. In case of failure, we performed awake fibreoptic tracheal intubation. We found insertion of the device was successful and well tolerated in all patients. Vocal cords could be seen immediately in nine patients and following corrective manoeuvres in 10 patients. Tracheal intubation was successful in 20 patients: 19 cases under direct vision and in one blindly. In one patient with undiagnosed lingual tonsil hyperplasia, tracheal intubation was impossible using the device. No patient had an unpleasant recall of the procedure. We conclude that the LMA CTrach is easy to use, well tolerated and suitable for awake orotracheal intubation in patients with known difficult airways. [ABSTRACT FROM AUTHOR]

Seventy elderly males received lumbar epidural anaesthesia with 12 ml of 2% lidocaine containing fentanyl 50 μg. At the end of transurethral surgery, the washout group ( n = 33) received an epidural bolus of 30 ml saline while the control group ( n = 34) did not. Mean (SD) times to 1-grade (17.2 (11.9) vs 32.7 (11.3) min) and 2-grade regression (23.8 (12.2) vs 56.0 (23.9) min) of motor block, 3-dermatomal sensory regression (31.4 (11.6) vs 42.2 (14.4) min for cold and 30.8 (15.6) vs 40.6 (14.2) min for pinprick), and regression to S1 (57.7 (16.1) vs 76.2 (20.2) min for cold and 56.8 (17.3) vs 69.2 (16.2) min for pinprick) were significantly shorter in the washout group than the control group. There were no differences in postoperative pain scores and side effects between the two groups. We concluded that epidural washout facilitates regression of both motor and sensory block following epidural anaesthesia without reducing the postoperative analgesic benefit. [ABSTRACT FROM AUTHOR]

Laryngoscopy and tracheal intubation may provoke changes of cardiac repolarisation. The aim of this study was to assess the effect of intravenous lidocaine on the ECG changes induced by laryngoscopy and tracheal intubation. Forty-three female patients were randomly allocated to receive lidocaine (1.5 mg.kg−1) or placebo immediately after induction of anaesthesia and changes in the ECG and arterial blood pressure were recorded. Correction of QT interval was calculated using Bazett’s formula (QTcb), Fridericia’s correction (QTcf), and Framingham formula (QTcF). Transmural dispersion of repolarisation (TDR) was determined as Tpeak-Tend time. There were no changes in the QTc value in the lidocaine group. In the placebo group, significant increases in QTcb, QTcf and QTcF values were observed after intubation compared to either control measurements or to comparative measurements in the lidocaine group. There were no significant differences in TDR either between or within the groups. Lidocaine diminishes prolongation of QTc, induced by tracheal intubation but there is no effect of intubation on TDR. [ABSTRACT FROM AUTHOR]

This study was performed to investigate the incidence of remifentanil-induced cough and evaluate the efficacy of lidocaine on its prevention. Five-hundred patients, aged 18–70 years, were randomly allocated into two groups to receive either lidocaine 0.5 mg.kg−1 or 0.9% normal saline intravenously 1 min before remifentanil administration at a target effect-site concentration of 4 ng.ml−1. Any episode of cough was classified as coughing and graded as mild (1–2), moderate (3–4) or severe (5 or more). We found that the overall incidence of cough was significantly higher in the saline group (69 patients; 27.6%) than that in the lidocaine group (38 patients; 15.2%) (p < 0.001). The results of logistic regression indicated that age and smoking were associated with remifentanil-induced cough. This study demonstrated that intravenously administered lidocaine 0.5 mg.kg−1 effectively suppresses remifentanil-induced cough without possible systemic lidocaine toxicity. [ABSTRACT FROM AUTHOR]

Epidural mixtures containing lidocaine with or without additives are commonly used to convert epidural analgesia in labour to anaesthesia for emergency Caesarean section, but direct comparisons with alternative, single agents in this situation are few. In a prospective double-blinded trial, we compared a freshly prepared lidocaine-bicarbonate-adrenaline mixture (final concentrations 1.8%, 0.76% and 1 : 200,000, respectively) with our standard agent, levobupivacaine 0.5%, for extending epidural blockade for emergency Caesarean section. Using a sequential analysis technique, with data analysed in blocks of 40, women receiving epidural analgesia in labour who required top-up for Caesarean section were randomly assigned to receive 20 ml of epidural solution over 3 min. The first analysis ( n = 40) indicated that the study should be stopped, as significant differences were found in our primary outcome data. Median (IQR [range]) times to reach a block to touch to T5 and cold to T4 were, respectively, 7 (6–9 [5–17]) min and 7 (5–8 [4–17]) min for lidocaine-bicarbonate-adrenaline, and 14 (10 −17 [9–31]) min and 11 (9–14 [6–30]) min for levobupivacaine (p = 0.00004 and 0.001, respectively). Pre- and intra-operative supplementation/pain, maternal side-effects and neonatal outcomes (excluding five women who underwent instrumental delivery) were similar between the groups. Intra-operative maternal sedation (scored by the mother on a 10-point scale) was greater with lidocaine-bicarbonate-adrenaline (4.5 (3–8 [1–9])) than with levobupivacaine (3 (1–4 [1–7])), but not significantly so (p = 0.07). We conclude that epidural lidocaine-bicarbonate-adrenaline halves the onset time when extending epidural analgesia for Caesarean section although there is a possibility of increased maternal sedation. [ABSTRACT FROM AUTHOR]

We studied 45 ASA I/II children aged between 2 and 13 years scheduled for elective strabismus surgery, randomly allocated to receive either a peribulbar block or topical lidocaine 2% combined with general anaesthesia, or general anaesthesia alone. The incidence and severity of the occulocardiac reflex, the requirement for atropine, the occurrence of arrhythmias and incidence of postoperative nausea and vomiting following surgery at 1, 2 and 4 h were studied. We found the incidence and severity of occulocardiac reflex intra-operatively was significantly reduced in children who received a peribulbar block. The incidence of postoperative nausea and vomiting was significantly reduced in patients receiving either peribulbar block or topical local anaesthesia combined with general anaesthesia, compared to general anaesthesia alone (p = 0.008). [ABSTRACT FROM AUTHOR]

We 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) μg.ml−1 compared with 6.5 (1.0) μg.ml−1, p < 0.05). Airway anaesthesia using atomised lidocaine for awake fibreoptic intubation in the morbidly obese is efficacious, rapid, and safe. Compared with 4% lidocaine, the 2% dose provides acceptable intubating conditions in most cases and produces lower plasma lidocaine levels. [ABSTRACT FROM AUTHOR]

The vasodilator properties of lidocaine are believed to be due mainly to the inhibition of action potentials via sodium channel blocking in vasoconstrictor sympathetic nerves. However, mechanisms involving the vascular endothelium may also play a role, and in this study we investigated the potential influences of nitric oxide release, the cyclo-oxygenase pathway and the β-adrenoceptors of vascular smooth muscle. Laser Doppler imaging was used to measure microvascular blood flow responses to intradermal injection of lidocaine 2%, with or without the addition of preservatives, in eight healthy, male volunteers. Co-injection of the nitric-oxide–synthase inhibitor Nω-nitro-l-arginine methyl ester caused a 60% reduction in the response after about 20 min, and this reduction was enhanced with the lidocaine solution containing the preservatives methylhydroxybenzoate and propylhydroxybenzoate. No reduction in response was seen after blocking the cyclo-oxygenase or β-adrenoceptor pathways. Nitric oxide release contributes to the vasoactivity of lidocaine in human skin. [ABSTRACT FROM AUTHOR]

Medical students have difficulty calculating drug doses correctly, but better teaching improves their performance in written tests. We conducted a blinded, randomised, controlled trial to assess the benefit of online teaching on students' ability to administer drugs in a simulated critical incident scenario, during which they were scored on their ability to administer drugs in solution presented as a ratio (adrenaline) or percentage (lidocaine). Forty-eight final year medical students were invited to participate; 44 (92%) attended but only nine of the 20 students (45%) directed to the extra teaching viewed it. Nevertheless, the teaching module significantly improved the students' ability to calculate the correct volume of lidocaine (p = 0.005) and adrenaline (p = 0.0002), and benefited each student's overall performance (p = 0.0007). Drug administration error is a very major problem and few interventions are known to be effective. We show that focusing on better teaching at medical school may benefit patient safety. [ABSTRACT FROM AUTHOR]

Transdermal Delivery System (TDS®) is a liquid formulation which can be applied to the skin via a metered pump spray to deliver drug across skin. This placebo controlled, double blind trial compared anaesthetic properties of two TDS® systems (TDS®α and TDS®β) with placebo. The active and placebo treatments were applied to the dorsum of the hands, bilaterally and simultaneously for 5 min on 100 healthy volunteers. Following cannulation, pain perception was measured using the verbal rating score (VRS) and visual analogue score (VAS). Lidocaine plasma levels were assessed at 0 and 2 h. The VRS and VAS results show that TDS®β significantly decreased pain score compared to placebo (p < 0.02). Blood lidocaine at 2 h post application was also higher for TDS®β than for TDS®α, suggesting that a 5 min application of TDS®β was effective in delivering local anaesthetic and accelerating the onset of skin anaesthesia prior to venous cannulation in adults. [ABSTRACT FROM AUTHOR]

This article presents abstracts of medical research presented at the annual Congress of the Association of Anesthetists of Great Britain and Ireland in September 2005. They include "A Questionnaire Survey of Informed Consent for Central Neuraxial Regional Anesthesia," "The Design and Implementation of a Web-Based and Rule-Based Route Making System," "A Prospective Randomized Double-Blind Comparison of Propofol-Lipuro vs Propofol With or Without Lidocaine and the Effect on Injection Pain," "The Liver Resection and Hypovolaemia in Which a Technique Was Vindicated," and "The Cataract Surgery Under Local Anesthesia Without Supplemental Oxygen Therapy Which Has a Comparison of Two Drapes."