Concept: Endotracheal tube
General anesthesia is a safe, frequent procedure in clinical practice. Although it is very unusual in procedures not related to head and or neck surgery, vocal cord paralysis is a serious and important complication. Incidence has been associated with patient age and comorbidities, as well as the position of the endotracheal tube and cuff. It can become a dangerous scenario because it predisposes aspiration.
Providing supplemental oxygen is fundamental in the management of mechanically ventilated patients. Increasing amounts of data show worse clinical outcomes associated with hyperoxia. However, these previous data in the critically ill have not focused on outcomes associated with brief hyperoxia exposure immediately after endotracheal intubation. Therefore, the objectives of this study were to evaluate the impact of isolated early hyperoxia exposure in the emergency department (ED) on clinical outcomes among mechanically ventilated patients with subsequent normoxia in the intensive care unit (ICU).
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airway interventions are limited, and blind techniques using a bougie or through supraglottic airway devices have been superseded by video- or fibre-optically guided intubation.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.
Despite being infrequent, complications of airway management remain an important contributor to morbidity and mortality during anaesthesia and care of the critically ill. Developments in the last three decades have made anaesthesia safer, and this has been mirrored in the equipment and techniques available for airway management. Modern technology including novel oxygenation modalities, widespread availability of capnography, second-generation supraglottic airway devices and videolaryngoscopy provide the tools to make airway management safer still. However, technology will only take safety so far, and non-technical aspects of airway management are critically important for communication and decision making during airway crises, acknowledging a ‘cannot intubate, cannot oxygenate’ situation and transitioning to emergency front of neck airway. Randomised controlled trials provide little useful information about safety in this setting, and data from registries and databases are likely to be of more value. This narrative review focuses on recent evidence in this area.
These guidelines describe a comprehensive strategy to optimize oxygenation, airway management, and tracheal intubation in critically ill patients, in all hospital locations. They are a direct response to the 4th National Audit Project of the Royal College of Anaesthetists and Difficult Airway Society, which highlighted deficient management of these extremely vulnerable patients leading to major complications and avoidable deaths. They are founded on robust evidence where available, supplemented by expert consensus opinion where it is not. These guidelines recognize that improved outcomes of emergency airway management require closer attention to human factors, rather than simply introduction of new devices or improved technical proficiency. They stress the role of the airway team, a shared mental model, planning, and communication throughout airway management. The primacy of oxygenation including pre- and peroxygenation is emphasized. A modified rapid sequence approach is recommended. Optimal management is presented in an algorithm that combines Plans B and C, incorporating elements of the Vortex approach. To avoid delays and task fixation, the importance of limiting procedural attempts, promptly recognizing failure, and transitioning to the next algorithm step are emphasized. The guidelines recommend early use of a videolaryngoscope, with a screen visible to all, and second generation supraglottic airways for airway rescue. Recommendations for emergency front of neck airway are for a scalpel-bougie-tube technique while acknowledging the value of other techniques performed by trained experts. As most critical care airway catastrophes occur after intubation, from dislodged or blocked tubes, essential methods to avoid these complications are also emphasized.
The Obstetric Anaesthetists' Association and Difficult Airway Society have developed the first national obstetric guidelines for the safe management of difficult and failed tracheal intubation during general anaesthesia. They comprise four algorithms and two tables. A master algorithm provides an overview. Algorithm 1 gives a framework on how to optimise a safe general anaesthetic technique in the obstetric patient, and emphasises: planning and multidisciplinary communication; how to prevent the rapid oxygen desaturation seen in pregnant women by advocating nasal oxygenation and mask ventilation immediately after induction; limiting intubation attempts to two; and consideration of early release of cricoid pressure if difficulties are encountered. Algorithm 2 summarises the management after declaring failed tracheal intubation with clear decision points, and encourages early insertion of a (preferably second-generation) supraglottic airway device if appropriate. Algorithm 3 covers the management of the ‘can’t intubate, can’t oxygenate’ situation and emergency front-of-neck airway access, including the necessity for timely perimortem caesarean section if maternal oxygenation cannot be achieved. Table 1 gives a structure for assessing the individual factors relevant in the decision to awaken or proceed should intubation fail, which include: urgency related to maternal or fetal factors; seniority of the anaesthetist; obesity of the patient; surgical complexity; aspiration risk; potential difficulty with provision of alternative anaesthesia; and post-induction airway device and airway patency. This decision should be considered by the team in advance of performing a general anaesthetic to make a provisional plan should failed intubation occur. The table is also intended to be used as a teaching tool to facilitate discussion and learning regarding the complex nature of decision-making when faced with a failed intubation. Table 2 gives practical considerations of how to awaken or proceed with surgery. The background paper covers recommendations on drugs, new equipment, teaching and training.
A case of high-frequency jet ventilation (HFJV) during video-assisted thoracoscopicsurgery (VATS) in a patient with previous contralateral pneumonectomy is presented. A 77yearold man with a right pneumothorax was scheduled for bullectomy by VATS. He had undergone left pneumonectomy due to lung cancer 6 years earlier.Anesthesia was induced and maintained with propofol and fentanyl. The patient was intubated with a normal, single-lumen endotracheal tube (ETT).HFJV was applied through the ETT during the VATS procedure. Although PaCO(2) gradually increased from 51.9 mmHg to 80.0 mmHg, appropriate surgical conditions were provided, PaO(2) was well preserved, and blood pressure and heart rate were stable throughout the VATS procedure.
Review article: Video-laryngoscopy: another tool for difficult intubation or a new paradigm in airway management?
- Canadian journal of anaesthesia = Journal canadien d'anesthesie
- Published almost 8 years ago
BACKGROUND: An adequate airway management plan is essential for patient safety. Recently, new tools have been developed as alternatives to direct laryngoscopy and intubation. Among these, video-laryngoscopy has enjoyed a rapid increase in popularity and is now considered by many as the first-line technique in airway management. This paradigm shift may have an impact on patient safety. PRINCIPAL FINDINGS: Studies show that video-laryngoscopes are associated with better glottic visualization, a higher success rate for difficult airways, and a faster learning curve, resulting in a higher success rate for intubations by novice physicians. Thus, unanticipated difficult intubations may be less frequent if video-laryngoscopy is used as the first-line approach. In addition, on-screen viewing by the operator creates a new dynamic interaction during airway management. The entire operating room team can assess progress in real time, which enhances communication and improves teaching. However, if video-laryngoscopes become standard tools for tracheal intubation, these more costly devices will need to be widely available in all locations where airway management is conducted. Furthermore, algorithms for difficult intubation will require modification, and the question of selecting alternate devices will arise. If the incidence of difficult intubation decreases, the lack of motivation to teach and learn the use of alternative devices might adversely impact patient safety. CONCLUSION: The greater effectiveness of video-laryngoscopes associated with multi-person visualization could enhance overall patient safety during airway management. However, the routine use of video-laryngoscopy also introduces some issues that need to be addressed to avoid potentially dangerous pitfalls.
BACKGROUND: Modern high volume-low pressure (HVLP) endotracheal tubes (ETT) cuffs can seal the trachea using baseline cuff pressures (CP) lower than peak inspiratory airway pressures (PIP). The aim of the study was to determine whether this technique reduces the damage to the tracheal mucosa compared to constant CP of 20 cmH(2)O. METHODS: Eighteen piglets were intubated with an ID 4.0 mm HVLP cuffed ETT (Microcuff PET) and artificially ventilated with 20 cmH(2)O PIP and 5 cmH(2)O PEEP. Animals were randomly allocated to two groups of CP: group A (just seal; n = 9) and group B (20 cmH(2)O; n = 9), controlled constantly with a manometer during the following 4-h study period under sevoflurane anesthesia. After euthanasia, cuff position was marked in situ. Damage in the cuff region was evaluated with scanning electron microscopy (SEM) examination by grading of mucosal damage and by estimating percentage of intact mucosal area both by a blinded observer. RESULTS: Maximal CP to seal the trachea in group A ranged from 12 to 18 cmH(2)O (median: 14 cmH(2)O). Using a mixed effects model approach, the estimated mean effect of group B vs group A was an increase of 17.9% (SE 8.1%) higher proportion of pictures with an area of at least 5% intact mucosa (P = 0.042). CONCLUSION: Minimal sealing pressures with cyclic pressure changes from CP did not result in decreased damage to the tracheal mucosa compared to constant CP of 20 cmH(2)O in this short-term animal trial.
BACKGROUND: Stylet use during endotracheal intubation (ETI) is variable across medical specialty and geographic location; however, few objective data exist regarding the impact of stylet use on ETI performance. OBJECTIVE: We evaluated the impact of stylet use on the time required to perform ETI in cases of simulated difficult airways in novice and experienced providers. METHODS: We performed a prospective, randomized observational study of experienced (attending anesthesiologists and emergency physicians) vs inexperienced airway providers (emergency medical technician, paramedic and medical students) comparing the use of stylet vs no stylet in random order using a simulated difficult airway. The primary outcome was attempt time for each of 6 attempts defined as entry of the laryngoscope in the mouth until successfully passing the endotracheal tube past the vocal cords. We analyzed the data using descriptive statistics including means with SDs and t tests. We used generalized estimating equations to evaluate potential changes in the attempt time over multiple attempts. RESULTS: There were 23 providers per group. The mean (SD) inexperienced attempt time in seconds was 25.88 (28.46) and 10.50 (5.47) for experienced providers (P < .0001). Stylet use did not alter attempt time for either group. When adjusting for stylet use, the attempt time did not change over repeated intubations (P = .541). When adjusting for experience status, inexperienced intubators had shorter attempt times with each successive trial, whereas experienced intubators attempt times remained constant (P < .001). CONCLUSION: Stylet use does not improve attempt time in a simulated difficult airway model for either inexperienced or experienced intubators.