Evaluating contralateral neck failure in patients with lateralized OPSCC treated with transoral robotic surgery and neck management based on pre-operative SPECT-CT lymphatic mapping.

BACKGROUND: Risk of contralateral nodal metastases in oropharyngeal squamous cell carcinoma (OPSCC) is relatively low, however, many OPSCC patients receive bilateral neck treatment. This study evaluates the oncological outcomes with management of the contralateral cN0 neck based on lymphatic mapping with single photon emission computed tomography (SPECT-CT). METHODS: Retrospective evaluation of patients with lateralized cT1-2 and contralateral cN0 OPSCC treated with primary surgery between December 2017 and October 2019. All patients underwent pre-operative lymphatic mapping using SPECT-CT. Clinical parameters including demographics, tumor characteristics and oncological outcomes were recorded. RESULTS: Thirteen patients underwent primary site resection with transoral robotic surgery (TORS) and ipsilateral neck dissection with or without adjuvant therapy. Twelve patients (92.3%) had ipsilateral drainage on SPECT-CT, whereas 1 (7.7%) patient had bilateral neck lymphatic drainage. Four patients (30.8%) underwent post-operative radiation therapy (PORT). Three patients with unilateral drainage on SPECT-CT underwent PORT with unilateral neck irradiation, and 1 patient with bilateral drainage underwent PORT with bilateral neck irradiation. Seven (53.8%) patients were staged as pT1, 6 (46.2%) patients as pT2, 6 (46.2%) patients were pN0, 3 (23.1%) patients were pN1, 1 (7.7%) patient was pN2a for and 3 (23.1%) patients were N2b. The median distance of the tumor from midline was 1.05 cm (0.0-1.58). Primary sites included tonsil (n = 10, 76.9%) and tongue base (n = 3, 23.1%). The median follow-up time was 15.4 months. All patients were disease free at the latest follow-up with no contralateral neck failures. CONCLUSIONS: Pre-operative mapping of lymphatic drainage in early stage OPSCC with SPECT-CT is a promising tool which can reduce treatment to the contralateral neck potentially without compromising oncological outcomes.

Extubation of the Challenging or Difficult Airway.

PURPOSE OF REVIEW: This review explores relevant definitions, epidemiology, management, and potential future research directions in the extubation of the challenging/difficult airway. It provides guidance on identifying patients at risk and how to approach these clinical scenarios. RECENT FINDINGS: Based on recent literature, including large-scale audits and closed claims analysis, it is increasingly recognized that extubation of the difficult airway is a situation at risk of severe adverse events. Some strategies to manage the extubation of the challenging/difficult airway have been described. SUMMARY: Extubating the challenging/difficult airway is a high-risk situation. However, it is fundamental to keep in mind that intended extubation is always an elective procedure. As such, it is imperative to adhere to principles of careful patient and context assessment, planning, and execution only when optimal conditions have been secured.

Direct versus indirect laryngoscopy using a Macintosh video laryngoscope: a mannequin study comparing applied forces.

PURPOSE: Upper airway injury and sympathetic activation may be related to the forces applied during laryngoscopy. We compared the applied forces during laryngoscopy using direct and indirect visualization of a standardized mannequin glottis. METHODS: Force transducers were applied to the concave surface of a GlideScope T-MAC Macintosh-style video laryngoscope that can also be used as a conventional direct-view laryngoscope. Thirty-four anesthesiologists performed four laryngoscopies (two direct and two indirect views) on an Ambu mannequin in a randomized sequence. During each laryngoscopy, participants were instructed to obtain views corresponding to > 80% and 50% of the glottic opening aperture. Peak and impulse forces were measured for each view. RESULTS: To achieve a 50% glottic opening view, the top 10th percentile force was higher with direct vs indirect laryngoscopy in terms of peak (difference, 9.1 newton; 99% confidence interval [CI], 7.4 to 13.9) and impulse (difference, 56.4 newton·sec; 99% CI, 49.0 to 81.7) forces. To achieve >80% view of the glottic opening, median force was higher with direct vs indirect laryngoscopy in terms of peak (difference, 3.6 newton; 99% CI, 1.6 to 7.3) and impulse (difference, 20.4 newton·sec; 99% CI, 11.7 to 35.1) forces. CONCLUSIONS: In this mannequin study, lower forces applied during indirect vs direct laryngoscopy may reflect an advantage of video laryngoscopy, but additional studies using patients are required to confirm the clinical implications of these findings.

RéSUMé: OBJECTIF: Les lésions aux voies aériennes supérieures et l'activation du système sympathique pourraient être dues aux forces appliquées pendant la laryngoscopie. Nous avons comparé les forces appliquées pendant une laryngoscopie avec visualisation directe vs indirecte d'une glotte standardisée sur mannequin. MéTHODE: Des transducteurs ont été appliqués à la surface concave d'un vidéolaryngoscope de type Macintosh GlideScope T-MAC, un dispositif qui peut également être utilisé comme laryngoscope conventionnel avec visualisation directe. Trente-quatre anesthésiologistes ont chacun réalisé quatre laryngoscopies (deux visualisations directes et deux indirectes) sur un mannequin Ambu en suivant une séquence randomisée. Pendant chaque laryngoscopie, les participants avaient pour consigne d'obtenir des vues correspondant à > 80 % et 50 % de l'ouverture glottique. Les forces maximales et impulsions ont été mesurées pour chaque visualisation. RéSULTATS: Pour obtenir une visualisation à 50 % de l'ouverture glottique, le 10e percentile maximal était plus élevé en cas de laryngoscopie directe qu'en cas de laryngoscopie indirecte tant au maximum de la force (différence, 9,1 newton; intervalle de confiance [IC] 99 %, 7,4 à 13,9) qu'à l'impulsion (différence, 56,4 newton·sec; IC 99 %, 49,0 à 81,7). Pour obtenir une visualisation à > 80 % de l'ouverture glottique, la médiane était également plus élevée en cas de laryngoscopie directe qu'en cas de laryngoscopie indirecte, tant au maximum de la force (différence, 3,6 newton; intervalle de confiance [IC] 99 %, 1,6 à 7,3) qu'à l'impulsion (différence, 20,4 newton·sec; IC 99 %, 11,7 à 35,1). CONCLUSION: Dans cette étude sur mannequin, les forces et impulsions moins prononcées appliquées pendant la laryngoscopie indirecte plutôt que directe pourraient refléter un avantage de la vidéolaryngoscopie, mais des études supplémentaires sur patient sont nécessaires afin de confirmer les implications cliniques de ces résultats.

Lymphatic mapping with SPECT-CT for evaluation of contralateral drainage in lateralized oropharyngeal cancers using an awake injection technique.

BACKGROUND: Risk of contralateral nodal metastases in oropharyngeal squamous cell carcinoma (OPSCC) is currently based on clinical risk factors. We propose lymphatic mapping with single photon emission computed tomography (SPECT-CT) for tumor-specific delineation of lymphatic drainage to guide treatment. METHODS: Retrospective review of lymphatic drainage patterns in cT1-2 OPSCC and contralateral cN0 neck with a nonoperative, awake injection of 99 m-Tc sulfur colloid and SPECT-CT. RESULTS: Ten patients were reviewed. Primary sites included tonsil (n = 8, 80%) and tongue base (n = 2, 20%). All patients tolerated awake injections with no complications. Nine patients (90%) demonstrated satisfactory migration of radiotracer to neck node(s) with seven (78%) to the ipsilateral lateral neck, one (11%) to the ipsilateral lateral neck and retropharynx, and one (11%) to bilateral lateral neck nodes. CONCLUSIONS: Characterization of lymphatic drainage in OPSCC is feasible using a nonoperative injection technique and SPECT-CT. Drainage to the contralateral neck is rare, warranting further study to tailor treatment appropriately.

Preparation for and Management of "Failed" Laryngoscopy and/or Intubation.

An airway manager's primary objective is to provide a path to oxygenation. This can be achieved by means of a facemask, a supraglottic airway, or a tracheal tube. If one method fails, an alternative approach may avert hypoxia. We cannot always predict the difficulties with each of the methods, but these difficulties may be overcome by an alternative technique. Each unsuccessful attempt to maintain oxygenation is time lost and may incrementally increase the risk of hypoxia, trauma, and airway obstruction necessitating a surgical airway. We should strive to optimize each effort. Differentiation between failed laryngoscopy and failed intubation is important because the solutions differ. Failed facemask ventilation may be easily managed with an supraglottic airway or alternatively tracheal intubation. When alveolar ventilation cannot be achieved by facemask, supraglottic airway, or tracheal intubation, every anesthesiologist should be prepared to perform an emergency surgical airway to avert disaster.

Measurement of forces applied using a Macintosh direct laryngoscope compared with a Glidescope video laryngoscope in patients with predictors of difficult laryngoscopy: A randomised controlled trial.

BACKGROUND: In patients with predictive features associated with easy direct laryngoscopy, videolaryngoscoy with the GlideScope has been shown to require less force when compared with Macintosh direct laryngoscopy. OBJECTIVE: The aim of this study was to compare forces applied with Glidescope vs. Macintosh laryngoscopes in patients with predictive features associated with difficult direct laryngoscopy. DESIGN: A randomised study. SETTING: Toronto General Hospital, a university tertiary centre in Canada. PATIENTS: Forty-four patients aged over 18 years, with one or more features of difficult intubation, undergoing elective surgery requiring single-lumen tracheal intubation. INTERVENTION: We measured the force applied to oropharyngeal tissues by attaching three FlexiForce Sensors (A201-25) to the concave surface of Macintosh and GlideScope laryngoscope blades.Anaesthetists or experienced anaesthesia residents performed laryngoscopies with both devices in a randomised sequence. MAIN OUTCOME MEASURES: The primary outcome was peak force. The secondary outcomes were average force and impulse force. The latter is the integral of the force over the time during which the force acted. RESULTS: Complete data were available for 40 individuals. Peak and average forces decreased with GlideScope (17 vs. 21 N, P = 0.03, and 6 vs. 11 N, P < 0.001, respectively). Laryngoscopy time increased with the GlideScope (30 vs. 18 s, P < 0.001), resulting in similar median impulse forces (206 vs. 175 N, P = 0.92). CONCLUSION: GlideScope laryngoscopy resulted in reduced peak and average forces, but as the laryngoscopy duration increased, the product of force and time (impulse force) was similar with both devices. TRIAL REGISTRATION: Clinicaltrials.gov Identifier: NCT01814176.

Improved nucleic acid extraction protocols for Ganoderma boninense, G. miniatocinctum and G. tornatum.

The first and most crucial step of all molecular techniques is to isolate high quality and intact nucleic acids. However, DNA and RNA isolation from fungal samples are usually difficult due to the cell walls that are relatively unsusceptible to lysis and often resistant to traditional extraction procedures. Although there are many extraction protocols for Ganoderma species, different extraction protocols have been applied to different species to obtain high yields of good quality nucleic acids, especially for genome and transcriptome sequencing. Ganoderma species, mainly G. boninense causes the basal stem rot disease, a devastating disease that plagues the oil palm industry. Here, we describe modified DNA extraction protocols for G. boninense, G. miniatocinctum and G. tornatum, and an RNA extraction protocol for G. boninense. The modified salting out DNA extraction protocol is suitable for G. boninense and G. miniatocinctum while the modified high salt and low pH protocol is suitable for G. tornatum. The modified DNA and RNA extraction protocols were able to produce high quality genomic DNA and total RNA of ~ 140 to 160 µg/g and ~ 80 µg/g of mycelia respectively, for Single Molecule Real Time (PacBio Sequel® System) and Illumina sequencing. These protocols will benefit those studying the oil palm pathogens at nucleotide level.

Supraglottic airway devices: indications, contraindications and management.

Supraglottic airway devices (SADs) have become an essential tool in airway management. Over the past three decades, these devices have been increasingly adopted as an alternative to face mask ventilation and/or endotracheal intubation. The range of proposed uses and features has increased significantly. They are used in pre- and in-hospital settings, elective and emergency anesthesia, in spontaneously breathing and ventilated patients, as conduits for intubation, as a bridge to extubation and for airway rescue. With SADs, serious complications such as aspiration and loss of airway are rare and largely preventable. Adequate operator experience, familiarity with the selected device, attention to details and careful patient selection are fundamental to safety and proficiency. In this review, we explore the increasing proposed uses for SADs and discuss possible complications and the management of these.

The effect of verbal and video feedback on learning direct laryngoscopy among novice laryngoscopists: a randomized pilot study.

PURPOSE: Skill acquisition in direct laryngoscopy (DL) and tracheal intubation is complex. This pilot study aims to assess feasibility and determine sample size for a subsequent trial comparing DL instruction using a Macintosh-style video laryngoscope (MacVL), with and without video recordings, with conventional DL instruction. METHODS: Medical students with no prior laryngoscopy experience were recruited during their two-week anesthesia rotation. During the first (TRAINING) week, students were randomized into three groups: Control (Macintosh direct laryngoscope), VL-1 (MacVL with real-time feedback), and VL-2 (MacVL with real-time feedback plus video recordings of laryngoscopies). During the second (TESTING) week, all students were tested using a Macintosh direct laryngoscope. Feasibility objectives were recruitment and attrition rates, ability to time and video record intubations, and the availability of a MacVL. The primary clinical outcome during the TESTING week was total time to intubate, and secondary outcomes included intubation success rate, intubating opportunities, complications, and confidence scores. RESULTS: Sixty-eight of 87 (78%) consecutive medical students approached to participate in the study were recruited over 18 months. Eight (12%) students withdrew from the study, and data are available on the remaining 60 participants. The times to intubate were recorded for 92% of the TESTING intubations, but only 71% of the TRAINING intubations in the VL-2 group were video recorded. The MacVLs were available in 100% of cases. We estimate that 190 participants would be required for a study restricted to a comparison of DL vs video laryngoscopy with real-time feedback. CONCLUSION: This pilot study establishes feasibility and provides a sample size estimate for a future RCT. Required modifications to the study protocol include wider hospital involvement and consideration regarding standardization of airway education, teaching, feedback, and patient characteristics.

Strengths and limitations of airway techniques.

After a prolonged period of stagnation, many new airway devices have entered the clinical arena. Along with these, practice guidelines based primarily on expert opinion have been endorsed by specialty societies. These guidelines encourage a rational progression in strategies rather than persistent ineffective efforts. It is important to have an understanding of the strengths and limitations of the devices and strategies relating to ventilation by face mask and supraglottic airway, the variety of fiberoptic and video laryngoscopic techniques, and the methods of reestablishing the airway after failed extubation.

Tracheal extubation and reintubation of the critically ill--challenges coming and going.

Tracheal reintubation is a common event in critical care. Elmer and colleagues provide the first comparison of complication rates of initial and subsequent reintubation(s) during the same hospitalization. Their work shows an increased risk of complications associated with reintubation, in particular hypoxemia and hypotension, reminding us to be cautious with patients having minimal reserve and potentially altered airway anatomy. See related research by Elmer et al., http://ccforum.com/content/19/1/12.

The difficult airway with recommendations for management--part 2--the anticipated difficult airway.

BACKGROUND: Appropriate planning is crucial to avoid morbidity and mortality when difficulty is anticipated with airway management. Many guidelines developed by national societies have focused on management of difficulty encountered in the unconscious patient; however, little guidance appears in the literature on how best to approach the patient with an anticipated difficult airway. METHODS: To review this and other subjects, the Canadian Airway Focus Group (CAFG) was re-formed. With representation from anesthesiology, emergency medicine, and critical care, CAFG members were assigned topics for review. As literature reviews were completed, results were presented and discussed during teleconferences and two face-to-face meetings. When appropriate, evidence- or consensus-based recommendations were made, and levels of evidence were assigned. PRINCIPAL FINDINGS: Previously published predictors of difficult direct laryngoscopy are widely known. More recent studies report predictors of difficult face mask ventilation, video laryngoscopy, use of a supraglottic device, and cricothyrotomy. All are important facets of a complete airway evaluation and must be considered when difficulty is anticipated with airway management. Many studies now document the increasing patient morbidity that occurs with multiple attempts at tracheal intubation. Therefore, when difficulty is anticipated, tracheal intubation after induction of general anesthesia should be considered only when success with the chosen device(s) can be predicted in a maximum of three attempts. Concomitant predicted difficulty using oxygenation by face mask or supraglottic device ventilation as a fallback makes an awake approach advisable. Contextual issues, such as patient cooperation, availability of additional skilled help, and the clinician's experience, must also be considered in deciding the appropriate strategy. CONCLUSIONS: With an appropriate airway evaluation and consideration of relevant contextual issues, a rational decision can be made on whether an awake approach to tracheal intubation will maximize patient safety or if airway management can safely proceed after induction of general anesthesia. With predicted difficulty, close attention should be paid to details of implementing the chosen approach. This should include having a plan in case of the failure of tracheal intubation or patient oxygenation.

The difficult airway with recommendations for management--part 1--difficult tracheal intubation encountered in an unconscious/induced patient.

BACKGROUND: Previously active in the mid-1990s, the Canadian Airway Focus Group (CAFG) studied the unanticipated difficult airway and made recommendations on management in a 1998 publication. The CAFG has since reconvened to examine more recent scientific literature on airway management. The Focus Group's mandate for this article was to arrive at updated practice recommendations for management of the unconscious/induced patient in whom difficult or failed tracheal intubation is encountered. METHODS: Nineteen clinicians with backgrounds in anesthesia, emergency medicine, and intensive care joined this iteration of the CAFG. Each member was assigned topics and conducted reviews of Medline, EMBASE, and Cochrane databases. Results were presented and discussed during multiple teleconferences and two face-to-face meetings. When appropriate, evidence- or consensus-based recommendations were made together with assigned levels of evidence modelled after previously published criteria. CONCLUSIONS: The clinician must be aware of the potential for harm to the patient that can occur with multiple attempts at tracheal intubation. This likelihood can be minimized by moving early from an unsuccessful primary intubation technique to an alternative "Plan B" technique if oxygenation by face mask or ventilation using a supraglottic device is non-problematic. Irrespective of the technique(s) used, failure to achieve successful tracheal intubation in a maximum of three attempts defines failed tracheal intubation and signals the need to engage an exit strategy. Failure to oxygenate by face mask or supraglottic device ventilation occurring in conjunction with failed tracheal intubation defines a failed oxygenation, "cannot intubate, cannot oxygenate" situation. Cricothyrotomy must then be undertaken without delay, although if not already tried, an expedited and concurrent attempt can be made to place a supraglottic device.