Neurologic toxicity of lidocaine during awake intubation in a patient with tongue base abscess. Case report

Modified anterior approach versus traditional posterior approach for ultrasound-guided superior laryngeal nerve block in awake endotracheal intubation: a randomized non-inferiority clinical trial

STUDY OBJECTIVE

This study was undertaken to compare the effect of the modified ultrasound-guided anterior superior laryngeal nerve block (SLNB) with the traditional ultrasound-guided posterior SLNB in providing intubation conditions during awake tracheal intubation (ATI) in patients without difficult airway.

DESIGN

Randomized, assessor-blind. Registration number: ChiCTR2200058086.

SETTING

West China Hospital of Sichuan University, Chengdu, China.

PATIENTS

104 patients aged 18-65 years, of American Society of Anesthesiologists status I-III, posted for elective general surgery with general endotracheal anesthesia.

INTERVENTIONS

The patients were randomized into two groups (modified group, n = 52; traditional group, n = 52). Modified anterior SLNB or traditional posterior SLNB was performed under ultrasound guidance.

MEASUREMENTS

The primary outcome was the proportion of acceptable intubation condition (AIC), which was analyzed in both per-protocol (PP) and intention-to-treat (ITT) populations. The prespecified non-inferiority margin was -4.8%. Secondary outcomes included intubation success rate on the first attempt, hemodynamic parameters during ATI, time taken for airway anesthesia and intubation, recall of intubation, patient perception of comfort, and incidence and severity of postoperative complications.

MAIN RESULTS

In the PP population, the proportion of AIC in the modified group was 49/49 (100%) and that in the traditional group was 49/49 (100%), absolute difference 0, lower limit of 1-sided 95% CI, -0.3%. In the ITT population, the primary outcomes in the modified and traditional group were 52/52 (100%) and 51/52 (98.1%), respectively, with an absolute difference of 1.9% and a lower limit of 1-sided 95% CI of -1.2%. The non-inferiority of modified ultrasound-guided anterior SLNB was confirmed in both populations.

CONCLUSIONS

Among adults without difficult airways during videolaryngoscope-assisted ATI, the modified ultrasound-guided anterior SLNB, compared to the traditional posterior approach, showed a statistically non-inferior effect in terms of providing AIC.

Airway nerve blocks for awake tracheal intubation: A meta-analysis of randomized control trials and trial sequential analysis

STUDY OBJECTIVE

This systematic review and meta-analysis aimed to assess the superiority of airway nerve blocks versus airway anesthesia without nerve blocks for awake tracheal intubation (ATI).

DESIGN

Systematic review and meta-analysis of randomized controlled trials (RCTs).

SETTING

All studies that assessed the superiority of airway anesthesia technique for awake tracheal intubation were searched in PubMed, Web of Science, Cochrane Library, Ovid Medline, Embase and Chinese databases (including China National Knowledge Infrastructure, Wanfang database, and VIP databases) and trial registry databases from their inception to December 2022.

PATIENTS

Adult patients included in randomized controlled trials comparing airway anesthesia with or without airway nerve blocks for ATI.

INTERVENTIONS

Airway nerve (including superior laryngeal nerve, glossopharyngeal nerve, or recurrent laryngeal nerve) blocks for ATI.

MEASUREMENTS

The primary outcome was the intubation time. Secondary outcomes were quality of intubating conditions (including patient reaction to placement of the flexible scope and tracheal tube, coughing and gagging, and patient satisfaction) and overall complications during ATI.

MAIN RESULTS

Fourteen articles with 658 patients were identified for analysis. When compared with airway anesthesia without nerve blocks, airway nerve blocks significantly reduced intubation time (standardized mean difference [SMD] -2.57, 95% CI -3.59- -1.56, p < 0.00001), improved anesthesia quality of ATI with higher no reaction to placement of the flexible scope and tracheal tube (relative risk [RR] 9.87; 95% CI 4.10-23.75, p < 0.00001), lower cough or gag reflex during intubation (RR 0.35, 95% CI 0.27-0.46, p < 0.00001), higher excellent patient satisfaction rate (RR 1.88, 95% CI 1.05-3.34, p = 0.03), and lower overall complications (RR 0.29, 95% CI 0.19-0.45, p < 0.00001). The overall quality of evidence was moderate.

CONCLUSIONS

Based on current published evidence, airway nerve blocks provide better airway anesthesia quality for ATI with a shorter intubation time, better intubation conditions including higher no reaction to placement of the flexible scope and tracheal tube, lower cough or gag reflex during intubation, higher excellent patient satisfaction, and lower overall complications.

Unilateral blindness following superior laryngeal nerve block for awake tracheal intubation in a case of posterior cervical spine surgery

Background:

Superior laryngeal nerve block (SUPLANEB) is a popular airway anesthesia technique utilized for successful awake endotracheal intubation in patients with significant cervical spine instability. If not performed by an expert, it carries the risk of general/neurologic complications that are typically minimal/transient. However, permanent blindness and/or upper cranial nerve neuropathies may occur. Here, we describe a case in which a young patient underwent an atlantoaxial fusion for a C2 nonunion (e.g., following a fracture) complicated by unilateral blindness due to a SUPLANEB.

Case Description:

A 25-year-old neurologically intact male underwent a C1-C2 posterior arthrodesis to address a nonunion of a C2 fracture. To perform the awake nasotracheal intubation, a SUPLANEB was performed using a video laryngoscope. Although the operation was uneventful, postoperatively, the patient reported left visual loss accompanied by left-sided facial numbness and hearing loss. On examination of the left eye, the anterior segment and fundus examinations were normal, but the OCT (optical coherence tomography) and retinal angiography demonstrated left-sided postischemic retinal edema with permeability of the intraocular vessels. Although the cranio-orbital computed tomography scan showed only mild pneumocephalus, the CT angiogram scan revealed abnormal air in the left carotid sheath accompanied by diffuse subcutaneous emphysema. Further, brain and orbital magnetic resonance imaging scans were normal. The patient was treated with pure oxygen, systemic steroid therapy, and nimodipine. The pneumocephalus and subcutaneous emphysema resolved on day 3. At 2 months follow-up, the patient remained blind on the left side, but had no further neurological deficits.

Conclusion:

Blindness and upper cranial nerves neuropathies should be considered as potential complications of SUPLANEB. Notably, these deficits were not directly related to the operative positioning or neurosurgical spinal procedure.

Local anaesthetic toxicity during an awake tracheal intubation course

We report a case of local anaesthetic toxicity in an anaesthetic trainee participating as a subject for an awake tracheal intubation training course. The trainee experienced symptoms of toxicity despite the dose of lidocaine administered being less than the maximum safe dose recommended for airway topicalisation. We argue this highlights the variability in absorption of local anaesthetic and the importance of safety during awake tracheal intubation training courses. It is essential to use the minimum safe dose of local anaesthetic required during topicalisation for awake tracheal intubation. We have now made it our course policy that participants cannot undergo awake tracheal intubation less than 2 weeks before a period of coryzal illness. We recommend that operators remain vigilant for signs of local anaesthetic toxicity when undertaking this procedure and adhere to newly published Difficult Airway Society awake tracheal intubation guidelines.

Difficult Airway Society guidelines for awake tracheal intubation (ATI) in adults

Awake tracheal intubation has a high success rate and a favourable safety profile but is underused in cases of anticipated difficult airway management. These guidelines are a comprehensive document to support decision making, preparation and practical performance of awake tracheal intubation. We performed a systematic review of the literature seeking all of the available evidence for each element of awake tracheal intubation in order to make recommendations. In the absence of high‐quality evidence, expert consensus and a Delphi study were used to formulate recommendations. We highlight key areas of awake tracheal intubation in which specific recommendations were made, which included: indications; procedural setup; checklists; oxygenation; airway topicalisation; sedation; verification of tracheal tube position; complications; management of unsuccessful awake tracheal intubation; post‐tracheal intubation management; consent; and training. We recognise that there are a range of techniques and regimens that may be effective and one such example technique is included. Breaking down the key practical elements of awake tracheal intubation into sedation, topicalisation, oxygenation and performance might help practitioners to plan, perform and address complications. These guidelines aim to support clinical practice and help lower the threshold for performing awake tracheal intubation when indicated.

Ultrasound-Guided Glossopharyngeal Nerve Block: A Cadaver and a Volunteer Sonoanatomy Study

BACKGROUND AND OBJECTIVES

Glossopharyngeal nerve (GPN) blocks are usually performed by topical, intraoral, or peristyloid approaches, which carry significant complication risks due to the proximity of important neurovascular structures. This study presents a proof of concept for a new ultrasound (US)-guided technique, which would block the GPN distally, in the parapharyngeal space, away from the immediate vicinity of high-risk collateral structures.

METHODS

Five cadaver heads were dissected, and the location of the GPN was explored bilaterally. In 40 healthy volunteers (20 men and 20 women; median age, 35.5 years [range, 24-69 years]) parapharyngeal sonograms were obtained, saved, and analyzed. To assess the technical feasibility of a distal GPN block in the parapharyngeal space, unilateral US-guided dye injections were performed in 3 fresh cadavers, followed by dissections.

RESULTS

The GPN was consistently identified between the stylopharyngeal and middle pharyngeal constrictor muscles in all cadaver specimens. The median distance between the GPN and the ipsilateral greater horn of the hyoid bone was 2.4 cm (range, 2.3-2.7 cm) on the right and 2.6 cm (range, 2.3-2.9 cm) on the left. The mean skin-to pharyngeal wall distances in the volunteers were 2.03 (SD, 0.41) cm on the right and 2.02 (SD, 0.45) cm on the left. The mean hyoid bone-to-pharyngeal wall distances were 2.04 (SD, 0.35) cm (right) and 2.07 (SD, 0.35) cm (left). The fresh cadaver dissections demonstrated dye deposition adjacent to the GPN in the parapharyngeal space in all specimens.

CONCLUSIONS

Based on our anatomical results in cadavers and healthy volunteers, we submit that successful and safe blockade of the distal GPN at the pharyngeal wall level is technically feasible under US guidance.

Another cause of difficult airway in an elderly patient: Tongue-base abscess

OBJECTIVE

An abscess of the tongue base is rare, but it can be a potentially life-threatening situation in elderly patients.

CASE REPORT

A 72-year-old male patient presented with mid-anterior neck swelling, odynophagia, poor oral hygiene and severe dyspnoea. After a difficult intubation, the muscles were dissected via a submental suprahyoid approach and the abscess was drained.

CONCLUSION

Poor oral hygiene may predispose elderly patients to tongue-base abscesses. An early decision should be made for surgical drainage due to the risk of airway obstruction.

Assessment of awake i-gel™ insertion for fiberoptic-guided intubation in patients with predicted difficult airway: A prospective, observational study

Background and Aims:

Orotracheal intubation (OTI) with fiberoptic bronchoscope (FOB) in spontaneous ventilation is one of the main techniques for patients with predicted difficult airway. Latest generation supraglottic airway devices have been designed to allow OTI through them. We assessed the safety and effectiveness of FOB-guided OTI through i-gel™ device which was inserted in spontaneously breathing patients with predicted difficult airway.

Material and Methods:

Eighty-five patients with difficult airway predictors were included. The i-gel was inserted under oropharyngeal local anaesthesia and sedation. After checking the adequate ventilation through the i-gel with capnography curve, general anaesthesia was induced in order to introduce the endotracheal tube guided by FOB. We recorded the i-gel insertion time (t_gel), intubation time (t_int), O₂ saturation in pulse oximetry (SpO₂) at different times: basal (t₀), after 3 min of preoxygenation with a face mask at 100% FiO₂ (t₁), after i-gel mask insertion (t₂) and after intubation (t₃). Adverse events during the procedure were also recorded.

Results:

All patients were successfully intubated. SpO₂ values were: 96.9 ± 1.2 (t₀), 99.0 ± 0.9 (t₁), 96.2 ± 2.4 (t₂), 96.0 ± 2.5 (t₃). t_gel and t_int were 38.0 ± 7.8 s and 36.5 ± 5.6 s, respectively. No serious adverse events were recorded and no patient suffered airway trauma.

Conclusion:

I-gel insertion in spontaneous ventilation secures the airway before achieving fiberoptic intubation without the occurrence of adverse events. More studies might be necessary in order to confirm the results presented, but we consider that the technique described is a safe and effective alternative to classic OTI with FOB in spontaneously breathing patients with predicted difficult airway.

Cytotoxicity and cellular response mechanisms of water-soluble platinum(II) complexes of lidocaine and phenylcyanamide derivatives

Three new platinum(II) complexes of lidocaine and phenylcyanamide derivative ligands of formula K[Pt(3,5-(NO₂)₂pcyd)₂(LC)], 1, K[Pt(3,5-(CF₃)₂pcyd)₂(LC)], 2, K[Pt(3,5-Cl₂pcyd)₂(LC)], 3 (LC: lidocaine, 3,5-(NO₂)₂pcyd: 3,5-dinitro phenylcyanamide, 3,5-(CF₃)₂pcyd: 3,5-bis(trifluoromethyl) phenylcyanamide, 3,5-Cl₂pcyd: 3,5-dichloro phenylcyanamide) have been synthesized and fully characterized. Cellular uptake, DNA platination and cytotoxicity against a panel of human tumor cell lines were evaluated. The complexes 1-3 revealed a significant in vitro antiproliferative activity against human ovarian carcinoma (A2780), colorectal adenocarcinoma (HT29), breast (MCF-7), liver hepatocellular carcinoma (HepG-2) and lung adenocarcinoma (A549) cancer cell lines. All the complexes are more active than cisplatin and follow the trend 1 > 2 > 3. Mechanistic studies showed that the trend in cytotoxicity of the Pt(II) complexes is mainly consistent with their ability to accumulate into cancer cells and to increase intracellular basal reactive oxygen species levels, which consequently results in the loss of mitochondrial membrane potential and apoptosis induction. The complex 1 caused to approximately 80-fold higher DNA platination level with respect to cisplatin. The complexes 1-3 can considerably stimulate the production of hydrogen peroxide in a time-dependent manner. Also, the complexes 1-3 induced an increase in reactive oxygen species (ROS) production that was superior to that induced by antimycin. The complex 1 had the most effect on ROS production in comparison with other complexes.

Fiberoptic-guided intubation after insertion of the i-gel airway device in spontaneously breathing patients with difficult airway predicted: a prospective observational study

STUDY OBJECTIVE

To assess the viability of performing fiberoptic-guided orotracheal intubation through the i-gel airway device previously inserted in spontaneously breathing patients with predicted difficult airway to achieve a patent airway.

DESIGN

Prospective observational study.

SETTING

Operating room in a tertiary care hospital.

PATIENTS

Eighty-five adult patients with at least 3 difficult airway predictors or difficult airway management history were included.

INTERVENTIONS

The i-gel device was inserted in spontaneous ventilation under oropharyngeal local anesthesia and sedation. After checking the adequate ventilation through the i-gel with capnography curve, general anesthesia was induced to introduce the endotracheal tube guided by fiberoptic bronchoscope.

MEASUREMENTS

We recorded the i-gel insertion time (tgel), intubation time (tint), and O₂ saturation in pulse oximetry in different moments: basal (t0), after 3 minutes of preoxygenation with a face mask at 100% fraction of inspired O₂ (t1), after i-gel mask insertion (t2), and after intubation (t3). Adverse events during the procedure were also recorded, and patient discomfort was questioned.

MAIN RESULTS

All patients were successfully intubated. O₂ saturation in pulse oximetry values were (mean±SD): 96.9±1.22 (t0), 99.0±0.85 (t1), 96.2±2.37 (t2), and 96.0±2.54 (t3). tgel and tint were 38.0±7.76 seconds and 36.5±5.55 seconds (mean±SD), respectively. No serious adverse events were recorded, and no patient suffered airway damage. Visual analogue scale for patient discomfort was 2 (interquartile range, 1-3).

CONCLUSIONS

i-gel insertion in spontaneously breathing patients avoids the "cannot ventilate" scenario. The subsequent fiberoptic-guided intubation through the i-gel is a safe and effective technique. More studies might be necessary to confirm the results presented, but we consider that the technique described is an adequate alternative to classic orotracheal intubation with fiberoptic bronchoscope in spontaneous ventilation for certain patients with predicted difficult airway.

Occurrence of bilateral pneumothorax during tracheostomy in a patient with deep neck infection

Infection that progresses to deep areas of the neck requires appropriate assessment of the airway, and securing of the airway is critical in patients with deep neck infection. In the patient in our case report, bilateral pneumothorax occurred while performing tracheostomy to the airways of a patient with deep neck infection, and therefore, this paper details the method used to secure the airway of patients with deep neck infection.

A comparison of the Enk Fiberoptic Atomizer Set(™) with boluses of topical anaesthesia for awake fibreoptic intubation

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.

Topical local anesthesia: focus on lidocaine-tetracaine combination

In recent years, the popularity of aesthetic and cosmetic procedures, often performed in outpatient settings, has strongly renewed interest in topical anesthetics. A number of different options are widely used, alone or in combination, in order to minimize the pain related to surgery. Moreover, interest in local anesthetics in the treatment of some painful degenerative conditions such as myofascial trigger point pain, shoulder impingement syndrome, or patellar tendinopathy is increasing. Numerous clinical trials have shown that lidocaine–tetracaine combination, recently approved for adults aged 18 or older, is effective and safe in managing pain. The present paper gives an overview of the recent literature regarding the efficacy and safety of lidocaine–tetracaine combination use.

Airway anesthesia: theory and practice

Topical anesthesia of the airway is a necessary for awake intubation and is usually achieved using lidocaine delivered by various means. Although some experts favor the use of airway blocks, a more common approach is to use pure topical methods in combination with "spray as you go" techniques. Once the topicalization is complete, the patient should be able to easily tolerate the use of an oral airway used to facilitate awake oral intubation. Nasal intubation requires additional topicalization of the nasal passages in conjunction with a vasoconstrictor. Finally, judicious sedation is frequently used when awake intubation is carried out.

The conformational stability, solvation and the assignments of the experimental infrared, Raman, (1)H and (13)C NMR spectra of the local anesthetic drug lidocaine

The structure, vibrational and (1)H and (13)C NMR spectra of the local anesthetic drug lidocaine were investigated by the B3LYP/6-311G(∗∗) calculations. The molecule was predicted to have the non-planar cis (NCCN∼0°) structures being about 2-6kcal/mol lower in energy than the corresponding trans (NCCN∼180°) forms. The calculated NCCN (9.6°) and CNCC (-132.2°) torsional angles were in a good qualitative agreement with the reported X-ray angles (3.1 and 13.0°, -102.67 and -77.9°, respectively, for H-bonded dimers). The Gibbs energy of solution of lidocaine in formamide, water, dimethylsulfoxide, acetonitrile, methanol, ethanol and chloroform solutions was estimated at the B3LYP level. The predicted affinity of lidocaine toward the alcohols, acetonitrile and chloroform solutions was in excellent agreement with the reported experimental solubility of the drug in organic solvents. The analysis of the observed vibrational spectra is consistent with the presence of lidocaine in only one conformation at room temperature. The (1)H and (13)C NMR spectra of lidocaine were interpreted by experimental and DFT calculated chemical shifts of the drug. The RMSD between experimental and theoretical (1)H and (13)C chemical shifts for lidocaine is 0.47 and 8.26ppm, respectively.