Anesthesia for Bronchoscopy-An Update

The field of interventional pulmonology has grown immensely and is increasingly recognized as a subspecialty. The new procedures introduced in the last decade pose unique challenges, and anesthesiologists need to readapt to their specific demands. In this review, we extensively discuss the pathophysiology, technical aspects, preprocedural preparation, anesthetic management, and postprocedural challenges of many new procedures such as navigational bronchoscopy, endobronchial valve deployment, and bronchial thermoplasty. Majority of these procedures are performed under general anesthesia with an endotracheal tube. Total intravenous anesthesia with rocuronium as a muscle relaxant seems to be the standard US practice. The easy availability and proven safety and efficacy of sugammadex as a reversal agent of rocuronium has decreased the need for high-dose remifentanil as an agent to avoid muscle relaxants. Additional research is available with regard to the utility of nebulized lidocaine and is discussed. Finally, two newer drugs administered for conscious sedation (typically without the need of an anesthesiologist) are likely to gain popularity in the future. Remimazolam is a new short-acting benzodiazepine with a relatively faster offset of clinical effects. Dexmedetomidine, a selective adrenergic agonist, is increasingly employed in bronchoscopy as a sedative during bronchoscopic procedures.

High Frequency Jet Ventilation or Mechanical Ventilation for Panendoscopy for Cervicofacial Cancer: A Retrospective Study

Introduction-the upper airway panendoscopy, performed under general anesthesia, is mandatory for the diagnosis of cervicofacial cancer. It is a challenging procedure because the anesthesiologist and the surgeon have to share the airway space together. There is no consensus about the ventilation strategy to adopt. Transtracheal high frequency jet ventilation (HFJV) is the traditional method in our institution. However, the COVID-19 pandemic forced us to change our practices because HFJV is a high risk for viral dissemination. Tracheal intubation and mechanical ventilation were recommended for all patients. Our retrospective study compares the two ventilation strategies for panendoscopy: high frequency jet ventilation (HFJV) and mechanical ventilation with orotracheal intubation (MVOI). Methods-we reviewed all panendoscopies performed before the pandemic in January and February 2020 (HFJV) and during the pandemic in April and May 2020 (MVOI). Minor patients, patients with a tracheotomy before or after, were excluded. We performed a multivariate analysis adjusted on unbalanced parameters between the two groups to compare the risk of desaturation. Results-we included 182 patients: 81 patients in the HFJV group and 80 in the MVOI group. After adjustments based on BMI, tumor localization, history of cervicofacial cancer surgery, and use of muscle relaxants, the patients from the HFJV group showed significantly less desaturation than the intubation group (9.9% vs. 17.5%, OR_a = 0.18, p = 0.047). Conclusion-HFJV limited the incidence of desaturation during upper airway panendoscopies in comparison to oral intubation.

High-flow Nasal Cannula versus Conventional Ventilation in Laryngeal Surgery: A Systematic Review and Meta-analysis

High-flow nasal cannula (HFNC) is an emerging option for maintaining oxygenation in patients undergoing laryngeal surgery, as an alternative to traditional tracheal ventilation and jet ventilation (JV). However, the data on its safety and efficacy is sparse. This study aims to aggregate the current data and compares the use of HFNC with tracheal intubation and jet ventilation in adult patients undergoing laryngeal surgery. We searched PubMed, MEDLINE (Medical Literature Analysis and Retrieval System Online, or MEDLARS Online), Embase (Excerpta Medica Database), Google Scholar, Cochrane Library, and Web of Science. Both observational studies and prospective comparative studies were included. Risk of bias was appraised with the Cochrane Collaboration Risk of Bias in Non-Randomized Studies - of Interventions (ROBINS-I) or RoB2 tools and the Joanna Briggs Institute (JBI) Critical Appraisal Checklist for case series. Data were extracted and tabulated as a systematic review. Summary statistics were performed. Meta-analyses and trial sequential analyses of the comparative studies were performed. Forty-three studies (14 HFNC, 22 JV, and seven comparative studies) with 8064 patients were included. In the meta-analysis of comparative studies, the duration of surgery was significantly reduced in the THRIVE (Transnasal Humidified Rapid-Insufflation Ventilatory Exchange) group, but the number of desaturations, need for rescue intervention, and peak end-tidal CO₂ were significantly increased compared to the conventional ventilation group. The evidence was of moderate certainty and there was no evidence of publication bias. In conclusion, HFNC may be as effective as tracheal intubation in oxygenation during laryngeal surgery in selected adult patients and reduces the duration of surgery but conventional ventilation with tracheal intubation may be safer. The safety of JV was comparable to HFNC.

Parameters of high-frequency jet ventilation using a mechanical lung model

High frequency jet ventilationis a mechanical lung ventilation method which uses a relatively high flow usually through an open system. This work examined the effect of high-frequency jet ventilation on respiratory parameters of an intubated patient simulated using a high-frequency jet ventilator attached to a ventilation monitor for measurements of ventilation parameters. The series of experiments altered specific parameters each time (respiratory rate, inspiratory-expiratory (I:E) ratio, and inspiratory pressure), under different lung compliances. A reduction of minute ventilation was observed alongside a rise in respiratory rate, with low airway pressures over the entire range of lung compliances. In addition, an I:E ratio of 2:1 to 1:1; and the tidal and minute volumes were directly related to the inspiratory pressure over all compliance settings. To conclude, the respiratory mechanics in high-frequency jet ventilation are very different from those of conventional rate ventilation in a lung model. Further studies on patients and/or a biological model are needed to investigate pCO2 and end-tidal carbon-dioxide during high-frequency jet ventilation.

Transtracheal jet ventilation in a general tertiary hospital: A 7-year audit

Airway management in patients presenting with severe airway obstruction can present a challenge to the anaesthetist, as conventional difficult airway pathways are often inappropriate. The use of a transtracheal jet cannula is an alternative means of airway securement, but lack of familiarity has limited its use in general tertiary hospitals. We report a retrospective audit of the use of transtracheal jet ventilation in a general tertiary healthcare centre over the past seven years, with a total of 50 patients with severe airway compromise undergoing pharyngolaryngeal surgery. Transtracheal jet ventilation was successful in 98% of patients, and was the definitive means of airway management in 43 cases. In six cases, the technique was a useful temporising measure while the airway was secured by other means. Minor complications occurred in 12% of patients. No major morbidities or mortalities were recorded. We conclude that transtracheal jet ventilation for high-risk pharyngolaryngeal surgery can be performed using a high frequency jet ventilator, with a high rate of success and only minor complications. Cannulation of the trachea below the cricothyroid membrane is feasible but more challenging. Low-flow apnoeic oxygenation through the transtracheal jet ventilation cannula maintains oxygenation during initial surgical airway manipulation.

Coping with airway emergencies: Get, Set, Go!

Airway emergencies are among the life-threatening events that are encountered in the operating room, emergency department or intensive care unit. They are important causes of preventable morbidity and mortality where time is the essence. It can be extremely challenging to rapidly assess the airway for early diagnosis and perform appropriate interventions simultaneously. Outcome depends on the implementation of an optimal strategy to establish a patent airway. Equally important is the overall stabilisation of the patient and management of the primary clinical condition as appropriate. Key components of management include early recognition of threatened airway, appropriate and timely airway intervention, and maintaining oxygenation. In this review, we describe aetiology, evaluation and management of airway emergencies.

Transtracheal flow-regulated oxygen insufflation-a simple and safe method for prolonging safe apnoea time in difficult airway management: A report of two cases

In the absence of upper airway patency, supraglottic methods of oxygen delivery become ineffective. We present two semi-elective difficult airway cases where oxygenation via the supraglottic route was deemed impractical due to upper airway obstruction. In order to facilitate safe airway management, apnoeic oxygenation was delivered via a narrow bore transtracheal cannula using a flow-regulated oxygen insufflator. The potential for safely prolonging apnoea time with this technique in both elective and emergency settings is discussed.

Supraglottic jet oxygenation and ventilation assisted fiberoptic intubation in a paralyzed patient with morbid obesity and obstructive sleep apnea: a case report

Background

Hypoxia is a major concern and cause of morbidity or mortality during tracheal intubation after anesthesia induction in a pathological obese patient with obstructive sleep apnea (OSA). We introduce a case using Supraglottic jet oxygenation and ventilation (SJOV) to promote oxygenation/ventilation during fiberoptic intubation in a paralyzed patient with morbid obesity and OSA.

Case presentation

A 46-year-old man weighting 176 kg with BMI 53.7 kg/m2 was scheduled for gastric volume reduction surgery to reduce body weight under general anesthesia. SpO2 decreased during induction, and two hand pressured mask ventilation partial failed. We then placed WEI Nasal Jet Tube (WNJ) in the patient’s right nostril to provide SJOV. Then fiberoptic bronchoscopy guided endotracheal intubation was performed via mouth approach, and vital signs were stable. The operation was successfully completed after 3 h. Patient recovered smoothly in hospital for 8 days and did not have any recall inside the operating room.

Conclusion

SJOV via WNJ could effectively maintain adequate oxygenation/ventilation during long time fiberoptic intubation in an apnea patient with morbid obesity and OSA after partial failure of two hand pressured mask ventilation, without obvious complications. This may provide a new effective approach for difficult airway management in these patients.

Risk factors and outcomes for airway failure versus non-airway failure in the intensive care unit: a multicenter observational study of 1514 extubation procedures

BACKGROUND

Patients liberated from invasive mechanical ventilation are at risk of extubation failure, including inability to breathe without a tracheal tube (airway failure) or without mechanical ventilation (non-airway failure). We sought to identify respective risk factors for airway failure and non-airway failure following extubation.

METHODS

The primary endpoint of this prospective, observational, multicenter study in 26 intensive care units was extubation failure, defined as need for reintubation within 48 h following extubation. A multinomial logistic regression model was used to identify risk factors for airway failure and non-airway failure.

RESULTS

Between 1 December 2013 and 1 May 2015, 1514 patients undergoing extubation were enrolled. The extubation-failure rate was 10.4% (157/1514), including 70/157 (45%) airway failures, 78/157 (50%) non-airway failures, and 9/157 (5%) mixed airway and non-airway failures. By multivariable analysis, risk factors for extubation failure were either common to airway failure and non-airway failure: intubation for coma (OR 4.979 (2.797-8.864), P < 0.0001 and OR 2.067 (1.217-3.510), P = 0.003, respectively, intubation for acute respiratory failure (OR 3.395 (1.877-6.138), P < 0.0001 and OR 2.067 (1.217-3.510), P = 0.007, respectively, absence of strong cough (OR 1.876 (1.047-3.362), P = 0.03 and OR 3.240 (1.786-5.879), P = 0.0001, respectively, or specific to each specific mechanism: female gender (OR 2.024 (1.187-3.450), P = 0.01), length of ventilation > 8 days (OR 1.956 (1.087-3.518), P = 0.025), copious secretions (OR 4.066 (2.268-7.292), P < 0.0001) were specific to airway failure, whereas non-obese status (OR 2.153 (1.052-4.408), P = 0.036) and sequential organ failure assessment (SOFA) score ≥ 8 (OR 1.848 (1.100-3.105), P = 0.02) were specific to non-airway failure. Both airway failure and non-airway failure were associated with ICU mortality (20% and 22%, respectively, as compared to 6% in patients with extubation success, P < 0.0001).

CONCLUSIONS

Specific risk factors have been identified, allowing us to distinguish between risk of airway failure and non-airway failure. The two conditions will be managed differently, both for prevention and curative strategies.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT 02450669 . Registered on 21 May 2015.

Guidelines and algorithms for managing the difficult airway

The difficult airway constitutes a continuous challenge for anesthesiologists. Guidelines and algorithms are key to preserving patient safety, by recommending specific plans and strategies that address predicted or unexpected difficult airway. However, there are currently no "gold standard" algorithms or universally accepted standards. The aim of this article is to present a synthesis of the recommendations of the main guidelines and difficult airway algorithms.

Anaesthetic management of acute airway obstruction

The acutely obstructed airway is a medical emergency that can potentially result in serious morbidity and mortality. Apart from the latest advancements in anaesthetic techniques, equipment and drugs, publications relevant to our topic, including the United Kingdom's 4th National Audit Project on major airway complications in 2011 and the updated American Society of Anesthesiologists' difficult airway algorithm of 2013, have recently been published. The former contained many reports of adverse events associated with the management of acute airway obstruction. By analysing the data and concepts from these two publications, this review article provides an update on management techniques for the acutely obstructed airway. We discuss the principles and factors relevant to the decision-making process in formulating a logical management plan.

Difficulties in Management of a Sessile Subglottic Polyp

Benign laryngeal polyps are usually managed with micro-laryngeal surgery. Occasionally surgery becomes challenging because of size of the polyp or its location. Maintaining the anaesthesia and the airway becomes difficult either during immediate management or during excision. Upper airway obstruction still remains the major indication for tracheostomy in many centers. Nowadays Laryngeal tumour has become the main indication of tracheostomy. Conditions like infections, trauma, benign lesions and prolonged intubation were leading indications previously. Otolaryngologist has to decide a method, often on the spot. Here we are presenting such a case where emergency tracheostomy was the only choice.

Difficult Airway Society 2015 guidelines for management of unanticipated difficult intubation in adults

These guidelines provide a strategy to manage unanticipated difficulty with tracheal intubation. They are founded on published evidence. Where evidence is lacking, they have been directed by feedback from members of the Difficult Airway Society and based on expert opinion. These guidelines have been informed by advances in the understanding of crisis management; they emphasize the recognition and declaration of difficulty during airway management. A simplified, single algorithm now covers unanticipated difficulties in both routine intubation and rapid sequence induction. Planning for failed intubation should form part of the pre-induction briefing, particularly for urgent surgery. Emphasis is placed on assessment, preparation, positioning, preoxygenation, maintenance of oxygenation, and minimizing trauma from airway interventions. It is recommended that the number of airway interventions are limited, and blind techniques using a bougie or through supraglottic airway devices have been superseded by video- or fibre-optically guided intubation. If tracheal intubation fails, supraglottic airway devices are recommended to provide a route for oxygenation while reviewing how to proceed. Second-generation devices have advantages and are recommended. When both tracheal intubation and supraglottic airway device insertion have failed, waking the patient is the default option. If at this stage, face-mask oxygenation is impossible in the presence of muscle relaxation, cricothyroidotomy should follow immediately. Scalpel cricothyroidotomy is recommended as the preferred rescue technique and should be practised by all anaesthetists. The plans outlined are designed to be simple and easy to follow. They should be regularly rehearsed and made familiar to the whole theatre team.

Acquired Glottic Stenosis-The Ongoing Challenge: A Review of Etiology, Pathogenesis, and Surgical Management

OBJECTIVE

To review the etiology and pathogenesis of acquired glottic stenosis, as well as the workup, patient preparation, interventional options, and their changing trends, as described in the literature since the 19th century until the present day.

METHODS

Literature from the PubMed search engine and the authors' personal experience were used. The search included up to date studies and historical reports covering different aspects of glottic stenosis, such as basic science, pathogenesis, anesthesia, and surgical techniques.

RESULTS

At present, the most common etiology for acquired glottic stenosis is damage to the posterior commissure after intubation. Until less than a century ago, infectious diseases such as diphtheria and syphilis were the most prevalent etiologies. The common pathway of stenosis includes mucosal and cartilaginous ulcers, granulation formation, fibrosis, and tethering scars. Planning of surgical intervention must begin with the matching of expectations with the patient and considering voice versus airway functions. Preoperative tracheotomy should be considered for securing the airway. Anesthesia has to be carefully planned, and both the surgeon and the anesthesiologist have to be familiar with the options for tubeless jet ventilation. Surgical options include a variety of open and endoscopic resection and reconstruction procedures, which are reviewed in this article, followed by images and illustrations based on the authors' experience.

CONCLUSION

Acquired glottic stenosis compromises the breathing, voice production, and airway protection. Reconstructing the stenosed glottis is one of the major challenges facing laryngologists in this era. For this reason, the surgeon must be familiar with the variety of treatment options.

The critical airway in adults: The facts

An algorithm on the indications and timing for a surgical airway in emergency as such cannot be drawn due to the multiplicity of variables and the inapplicability in the context of life-threatening critical emergency, where human brain elaborates decisions better in cluster rather than in binary fashion. In particular, in emergency or urgent scenarios, there is no clear or established consensus as to specifically who should receive a tracheostomy as a life-saving procedure; and more importantly, when. The two classical indications for emergency tracheostomy (laryngeal injury and failure to secure airway with endotracheal intubation or cricothyroidotomy) are too generic and encompass a broad spectrum of possibilities. In literature, specific indications for emergency tracheostomy are scattered and are biased, partially comprehensive, not clearly described or not homogeneously gathered. The review highlights the indications and timing for an emergency surgical airway and gives recommendations on which surgical airway method to use in critical airway.

Tracheobronchial stenosis: causes and advances in management

Tracheobronchial stenosis, narrowing of the airways by neoplastic or nonneoplastic processes, may be focal, as occurs with postintubation tracheal stenosis or a focal narrowing from a tumor, or more diffuse, such as those caused by inflammatory diseases. Symptoms develop when the narrowing impedes flow and increases resistance within the airways. Computed tomography defines the extent and severity of disease; endoscopy facilitates understanding of the cause so that an algorithm for treatment can be devised. Bronchoscopic interventions include balloons, ablative treatment, and stenting to provide symptomatic relief. Surgical resection may be curative and a multidisciplinary approach to tracheobronchial stenosis is required.