Unanticipated Difficult Tracheal Intubation Research Articles

Development of A Machine Learning Model for Predicting Unanticipated Difficult Tracheal Intubation

The valid prediction of unanticipated difficult tracheal intubation (DTI) is very important in clinic anesthesia. The purpose of this study was to develop a machine learning model for predicting unanticipated DTI. A comprehensive analysis of two prospective observational difficult airway research programs was performed. In total, 3958 patients who underwent tracheal intubation were included in this study. Data were split into a training set and a test set according to 70%:30% randomly. XGBoost machine learning was used to develop a machine learning model for predicting unanticipated DTI. The F1 score was used as the main performance metric because of data imbalance. The model parameter tuning was performed in the training set via pipeline grid search with the aim of optimizing the F1 score. Then, the tuning model were used for unanticipated DTI prediction in the test set. The indicators feature importance and decision rule were analyzed. With the XGBoost machine learning model for unanticipated DTI prediction, the best F1 score of 0.500 ± 0.102 was obtained on the training set with ten-fold cross-validation. The XGBoost model had the area under the precision recall curve (AUPRC) 0.600 and the area under the receiver operating characteristic curve (AUROC) 0.924 with an F1 value of 0.57 in the test set. XGBoost was an effective machine learning model for unanticipated DTI prediction.

Betel-Nut Chewing Increases Difficulty in Tracheal Intubation.

Betel-nut chewing (BC) causes oral submucous fibrosis (OSF), and this leads to difficult tracheal intubation (DI). Unanticipated DI was reported in chewers with apparently normal preoperative airway evaluations (PAEs). This analysis aims to investigate whether BC is an independent risk on DI besides the common DI risk prediction factors. After the approval of Institutional Review Board and the written informed consent were obtained, 2,682 patients were enrolled in a cohort. PAEs, intubation difficulty scale (IDS), intubation time, and perceived DI were recorded prospectively. All 805 male patients received classical intubation, 307 with BC and 498 without BC were analyzed. Data were analyzed by Student's t-test and chi-square test. Stepwise logistic regression was performed to identify BC effects on IDS adjusting for related factors with WEKA (Waikato Environment for Knowledge Analysis; Machine Learning Group at the University of Waikato, Hamilton, New Zealand). Fewer BC patients were Cormack-Lehane (CL) grade I (38.9% vs. 47.6%) or IDS degree 〞Easy〞 (24.8% vs. 33.5%). Compared with IDS degree 〞Easy〞, patients in the BC group had a significantly higher odds ratio (OR) for 〞Slight + Moderate-Major〞 degree than in the non-BC group (adjusted OR, 1.75; 95% CI, 1.15-2.68). Compared with CL grade I, patients with BC was an independent risk for II (adjusted OR, 1.53; 95% CI, 1.02-2.32) and IV (adjusted OR, 3.25; 95% CI 1.01-10.49). Otherwise, patient's age ≥ 46 and the presence of teeth were also significant risk factors for IDS degree 〞Slight + Moderate-Major〞. BC increased not only the tracheal intubation difficulty in patients with apparent OSF but also in patients with PAEs. BC is an independent risk factor besides the commonly used DI prediction factors. We suggest physicians operating on BC patients to be better prepared for DI.

Development and Multidisciplinary Preliminary Validation of a 3-Dimensional-Printed Pediatric Airway Model for Emergency Airway Front-of-Neck Access Procedures.

Pediatric-specific difficult airway guidelines include algorithms for 3 scenarios: unanticipated difficult tracheal intubation, difficult mask ventilation, and cannot intubate/cannot ventilate. While rare, these instances may require front-of-neck access (FONA) to secure an airway until a definitive airway can be established. The aim of this study was to develop a pediatric FONA simulator evaluated by both anesthesiology and otolaryngology providers, promoting multidisciplinary airway management. A 3-dimensional-printed tracheal model was developed using rescaled, anatomically accurate dimensions from a computerized tomography scan using computer-aided design software. The medical grade silicone model was incorporated into a mannequin to create a low-cost, high-fidelity simulator. A multidisciplinary team of anesthesiology, otolaryngology, and simulation experts refined the model. Experts in airway management were recruited to rate the realism of the model's characteristics and features and their own ability to complete specific FONA-related tasks. Six expert raters (3 anesthesiology and 3 otolaryngology) were identified for multidisciplinary evaluation of model test content validity. Analysis of response data shows null variance within 1 or both specialties for a majority of the content validity tool elements. High and consistent absolute ratings for each domain indicate that the tested experts perceived this trainer as a realistic and highly valuable tool in its current state. The ability to practice front-of-neck emergency airway procedures safely and subsequently demonstrate proficiency on a child model has great implications regarding both quality of physician training and patient outcomes. This model may be incorporated into curricula to teach needle cricothyroidotomy and other FONA procedures to providers across disciplines.

Comparison of upper-lip bite test with other four predictors for predicting difficulty in intubation

Background: Unanticipated difficult tracheal intubation remains a primary concern of anaesthesiologists. The aim of the present study was to compare upper-lip bite test (ULBT) with other four predictors namely modified Mallampati test (MMT), thyromental distance (TMD), sternomental distance (SMD) and interincisor distance (IID) for predicting difficulty in intubation. Methods: Airway assessment indices were evaluated and compared in 60 American Society of Anesthesiologists physical status Grade I and II patients undergoing general anaesthesia at a tertiary care teaching hospital in South India. The cut-off points for defining the difficult intubation (DI) were as follows: for ULBT, Class III; MMT, Classes 3 and 4; TMD Results: DI was observed in 26.7% of all patients studied. Sensitivity, specificity, PPV, NPV and accuracy for ULBT were 6.3%, 97.7%, 50%, 74.1% and 73.3%, respectively, whereas those for MMT were 25%, 86.4%, 40%, 76% and 70%, respectively. MMT showed 50% sensitivity and 84.5% specificity in assessing difficulty in intubation when compared with ULBT, whereas all the other methods have shown 0% sensitivity. MMT is a better predictor of difficulty in intubation when compared with ULBT due to its high sensitivity, better specificity, PPV and accuracy. Conclusions: No single airway predictor was accurate in predicting DI. A combination of at least two or more airway predictors has to be analysed to arrive at a near-ideal difficult airway prediction.

Effects of using the simplified airway risk index vs usual airway assessment on unanticipated difficult tracheal intubation - a cluster randomized trial with 64,273 participants

BackgroundUnanticipated difficult intubation remains a challenge in anaesthesia. The Simplified Airway Risk Index (SARI) is a multivariable risk model consisting of seven independent risk factors for difficult intubation. Our aim was to compare preoperative airway assessment based on the SARI with usual airway assessment. MethodsFrom 01.10.2012 to 31.12.2013, 28 departments were cluster-randomized to apply the SARI model or usual airway assessment. The SARI group implemented the SARI model. The Non-SARI group continued usual airway assessment, thus reflecting a group of anaesthetists’ heterogeneous individual airway assessments. Preoperative prediction of difficult intubation and actual intubation difficulties were registered in the Danish Anaesthesia Database for both groups. Patients who were preoperatively scheduled for intubation by advanced techniques (e.g. video laryngoscopy; flexible optic scope) were excluded from the primary analysis. Primary outcomes were the proportions of unanticipated difficult and unanticipated easy intubation. ResultsA total of 26 departments (15 SARI and 11 Non-SARI) and 64 273 participants were included. In the primary analyses 29 209 SARI and 30 305 Non-SARI participants were included.In SARI departments 2.4% (696) of the participants had an unanticipated difficult intubation vs 2.4% (723) in Non-SARI departments. Odds ratio (OR) adjusted for design variables was 1.03 (95% CI: 0.77–1.38). The proportion of unanticipated easy intubation was 1.42% (415) in SARI departments vs 1.00% (302) in Non-SARI departments. Adjusted OR was 1.26 (0.68–2.34). ConclusionsUsing the SARI compared with usual airway assessment we detected no statistical significant changes in unanticipated difficult- or easy intubations. Clinical trial registration. NCT01718561.

All India Difficult Airway Association 2016 guidelines for the management of unanticipated difficult tracheal intubation in obstetrics.

The various physiological changes in pregnancy make the parturient vulnerable for early and rapid desaturation. Severe hypoxaemia during intubation can potentially compromise two lives (mother and foetus). Thus tracheal intubation in the pregnant patient poses unique challenges, and necessitates meticulous planning, ready availability of equipment and expertise to ensure maternal and foetal safety. The All India Difficult Airway Association (AIDAA) proposes a stepwise plan for the safe management of the airway in obstetric patients. These guidelines have been developed based on available evidence; wherever robust evidence was lacking, recommendations were arrived at by consensus opinion of airway experts, incorporating the responses to a questionnaire sent to members of the AIDAA and the Indian Society of Anaesthesiologists (ISA). Modified rapid sequence induction using gentle intermittent positive pressure ventilation with pressure limited to ≤20 cm H2O is acceptable. Partial or complete release of cricoid pressure is recommended when face mask ventilation, placement of supraglottic airway device (SAD) or tracheal intubation prove difficult. One should call for early expert assistance. Maternal SpO2 should be maintained ≥95%. Apnoeic oxygenation with nasal insufflation of 15 L/min oxygen during apnoea should be performed in all patients. If tracheal intubation fails, a second- generation SAD should be inserted. The decision to continue anaesthesia and surgery via the SAD, or perform fibreoptic-guided intubation via the SAD or wake up the patient depends on the urgency of surgery, foeto-maternal status and availability of resources and expertise. Emergency cricothyroidotomy must be performed if complete ventilation failure occurs.

All India Difficult Airway Association 2016 guidelines for the management of unanticipated difficult tracheal intubation in Paediatrics.

The All India Difficult Airway Association guidelines for the management of the unanticipated difficult tracheal intubation in paediatrics are developed to provide a structured, stepwise approach to manage unanticipated difficulty during tracheal intubation in children between 1 and 12 years of age. The incidence of unanticipated difficult airway in normal children is relatively rare. The recommendations for the management of difficult airway in children are mostly derived from extrapolation of adult data because of non-availability of proven evidence on the management of difficult airway in children. Children have a narrow margin of safety and mismanagement of the difficult airway can lead to disastrous consequences. In our country, a systematic approach to airway management in children is lacking, thus having a guideline would be beneficial. This is a sincere effort to protocolise airway management in children, using the best available evidence and consensus opinion put together to make airway management for children as safe as possible in our country.

All India Difficult Airway Association 2016 guidelines for the management of unanticipated difficult tracheal intubation in adults.

The All India Difficult Airway Association (AIDAA) guidelines for management of the unanticipated difficult airway in adults provide a structured, stepwise approach to manage unanticipated difficulty during tracheal intubation in adults. They have been developed based on the available evidence; wherever robust evidence was lacking, or to suit the needs and situation in India, recommendations were arrived at by consensus opinion of airway experts, incorporating the responses to a questionnaire sent to members of the AIDAA and the Indian Society of Anaesthesiologists. We recommend optimum pre-oxygenation and nasal insufflation of 15 L/min oxygen during apnoea in all patients, and calling for help if the initial attempt at intubation is unsuccessful. Transnasal humidified rapid insufflations of oxygen at 70 L/min (transnasal humidified rapid insufflation ventilatory exchange) should be used when available. We recommend no more than three attempts at tracheal intubation and two attempts at supraglottic airway device (SAD) insertion if intubation fails, provided oxygen saturation remains ≥ 95%. Intubation should be confirmed by capnography. Blind tracheal intubation through the SAD is not recommended. If SAD insertion fails, one final attempt at mask ventilation should be tried after ensuring neuromuscular blockade using the optimal technique for mask ventilation. Failure to intubate the trachea as well as an inability to ventilate the lungs by face mask and SAD constitutes ‘complete ventilation failure’, and emergency cricothyroidotomy should be performed. Patient counselling, documentation and standard reporting of the airway difficulty using a ‘difficult airway alert form’ must be done. In addition, the AIDAA provides suggestions for the contents of a difficult airway cart.

English

BACKGROUND: Unanticipated difficult tracheal intubation is a significant source of morbidity and mortality in anaesthetic practice which can be reduced by identification of potential difficult intubation. OBJECTIVE: We aimed the present study to know the incidence of difficult intubation, factors associated with it and the predictive value of various airway predictors in anticipating difficult visualization of larynx and difficult intubation. METHODS: 435 adult patients (>18 year) undergoing general anaesthesia with intubation were examined preoperatively for demographic details (age, sex, weight), dentition, airway pathology and six airway predictors i.e. Inter Incisor Gap (IIG), Modified Mallampatti Grading (MMPG), Upper lip bite test (ULBT), Thyromental distance (TMD), Sternomental distance (SMD) and subluxation of mandible (SLM). All patients were anaesthetized using standard protocol with thiopentone (5mg/kg) and succinylcholine (1.5 mg/kg). On direct laryngoscopy, Cormack Lehane (CL) grading was noted. CL grade I, II was defined as easy visualization of larynx (EVL) and CL grade III, IV as difficult visualization of larynx (DVL). Difficult intubation score (DIS) was calculated as sum of CL grade and number of intubation attempts. DIS of less than or equal to 4 was defined as easy intubation (EI) and DIS > 4 was defined as difficult intubation (DI).Sensitivity, specificity, positive and negative predictive value, positive and negative likelihood ratios(LR) and odd's ratio value for six airway predictor tests was calculated by standard formulae. RESULTS: Incidence of DVL was 12.65% (n=55) and DI was 9.65% (n=42), with no failed intubation. All airway tests had very high negative predictive value (>90%) which implicates they identify easy intubations more precisely. MMPG and ULBT were found as airway predictors for difficult intubation having odds ratio of 85.23 (95% CI 25.42- 285.89%) and 65.45 (95% CI 25.69-166.7%) respectively, along with very high sensitivity of 92.80% and 85.7% respectively. Presence of ULBT III is the best predictor of difficult intubation (+LR 21.97) and absence of MMPG III, IV is the best predictor of difficult intubation (-LR 0.091). Abnormal dentition and airway pathology also increase the risk of difficult intubation, P<0.001. CONCLUSION: We conclude that ULBT and MMPG are nearly perfect airway predictors and should be used routinely during pre-anesthetic visit for screening of difficult intubation.

Diagnostic value of the upper lip bite test in predicting difficulty in intubation with head and neck landmarks obtained from lateral neck X-ray

Background:Unanticipated difficult tracheal intubation remains a primary concern of anaesthesiologists and upper lip bite test (ULBT) is one of the assessments used in predicting difficult intubation. In this study, we aimed to check the utility of lateral neck X-ray measurements in improving the diagnostic value of the ULBT.Methods:In a prospective study conducted from January 2007 until December 2010, we recorded personal and demographic data of 4500 patients who entered the study and subjected them to standard lateral neck radiography. Before the induction of anaesthesia, clinical examination and ULBT results were recorded and during induction of anaesthesia laryngoscopic grading was evaluated and recorded in questionnaires. All the compiled data were analysed by SPSS 14.0 (SPSS Inc., Chicago, IL, USA) software. Diagnostic value for each test was calculated and compared.Results:Negative predictive values (NPVs) were high in all tests. ULBT had the highest specificity and NPV compared with the other tests. The positive predictive value for all the tests had been low, but marginally high in the ULBT.Conclusion:Although all the tests used had relatively acceptable predictive values, combination of tests appeared to be more predictive. Highest sensitivities were observed with ULBT, mandibulohyoid distance and thyromental distance respectively. Use of radiological parameters may not be suitable as screening tools, but may help in anticipating and preparing for a difficult scenario.

Creating Airway Management Guidelines for Casualties with Penetrating Airway Injuries

Anaesthetists in the Defence Medical Services (DMS) are currently dealing with casualties who have an increased prevalence of injuries due to blast, fragmentation and gunshot wounds. Despite guidelines already existing...

Pourquoi une fiche d’information du patient après une intubation difficile ?

Unanticipated difficult tracheal intubation may be challenging to anaesthesiologists. It is still associated with morbidity or mortality. Previous difficult intubation is vital information to organize appropriate airway management. Unfortunately, previous studies in the literature have shown that there is poor communication of this information. We propose in this article an airway alert form, following several criteria published in the literature. This is, in our opinion, an important step to improve the efficiency of guidelines on airway management and the overall quality of the anaesthesia process. Its efficacy to decrease morbidity related to difficult tracheal intubation remains to be demonstrated.

Predictive Performance of Three Multivariate Difficult Tracheal Intubation Models: A Double-Blind, Case-Controlled Study

We performed a case-controlled, double-blind study to examine the performance of three multivariate clinical models (Wilson, Arné, and Naguib models) in the prediction of unanticipated difficult intubation. The study group consisted of 97 patients in whom an unanticipated difficult intubation had occurred. For each difficult intubation patient, a matched control patient was selected in whom tracheal intubation had been easily accomplished. Postoperatively, a blinded investigator evaluated both patients. The clinical assessment included the patient's weight, height, age, Mallampati score, interincisor gap, thyromental distance, thyrosternal distance, neck circumference, Wilson risk sum score, history of previous difficult intubation, and diseases associated with difficult laryngoscopy or intubation. The Naguib model was significantly more sensitive (81.4%; P < 0.0001) than the Arné (54.6%) or Wilson (40.2%) models. Both the Naguib (76.8%) and Arné (74.7%) model classified more intubations correctly (P = 0.01) than the Wilson model (66.5%). The specificity of Arné, Wilson, and Naguib model was 94.9%, 92.8%, and 72.2%, respectively (P < 0.0001). The corresponding area under the receiver operating characteristic curve was 0.87, 0.79, and 0.82, respectively. Our new model for prediction of difficult intubation was developed using logistic regression and includes thyromental distance, Mallampati score, interincisor gap, and height. This model is 82.5% sensitive and 85.6% specific with an area under the receiver operating characteristic curve of 0.90.

Tracheal intubation

Tracheal intubation is an essential anaesthetic skill. It combines maintenance and protection of the airway, and has numerous indications. It is essential to be able to predict which patients are likely to be difficult to intubate. If difficult intubation is predicted, it is important to consider alternative means of intubation including awake fibre-optic intubation. Should unanticipated difficult tracheal intubation occur, it is essential to apply a failed intubation drill. Alternatives to tracheal intubation include the laryngeal mask and Combitube.

Difficult Airway Society guidelines for management of the unanticipated difficult intubation

Problems with tracheal intubation are infrequent but are the most common cause of anaesthetic death or brain damage. The clinical situation is not always managed well. The Difficult Airway Society (DAS) has developed guidelines for management of the unanticipated difficult tracheal intubation in the non-obstetric adult patient without upper airway obstruction. These guidelines have been developed by consensus and are based on evidence and experience. We have produced flow-charts for three scenarios: routine induction; rapid sequence induction; and failed intubation, increasing hypoxaemia and difficult ventilation in the paralysed, anaesthetised patient. The flow-charts are simple, clear and definitive. They can be fully implemented only when the necessary equipment and training are available. The guidelines received overwhelming support from the membership of the DAS. It is not intended that these guidelines should constitute a minimum standard of practice, nor are they to be regarded as a substitute for good clinical judgement.

The Three-Dimensional Computed Tomography Imaging and Prediction of Unanticipated Difficult Tracheal Intubation

The Three-Dimensional Computed Tomography Imaging and Prediction of Unanticipated Difficult Tracheal Intubation

The Three-Dimensional Computed Tomography Imaging and Prediction of Unanticipated Difficult Tracheal Intubation

In response We appreciate the interest and comments of Dr. Naguib regarding our case report (1). The patient probably received postoperative radiotherapy. However, details of the therapy were not clear because the treatment was done in another hospital 6 yr ago. Dr. Naguib suggested that a combination of clinical and radiologic tests improved prediction of difficult intubation (2). We agree with Dr. Naguib that increasing preoperative tests results in higher prediction rates for difficult intubation. However, despite careful preoperative evaluation, difficulties will not be predicted in some instances. Thus, most importantly, strategies to manage the unanticipated difficult airway should be preformulated and practiced. Dr. Naguib also pointed out that the measurements derived from the 3D-CT images did not improve the predictability of their models (2). Three factors could have been responsible for this result. First, the 3D-CT image is not appropriate for dynamic and qualitative airway assessment because we are unable to estimate the stretching of soft tissue. Therefore, the 3D-CT is useful when airway distortion is evident (3). Second, Dr. Naguib et al. (2) did not mention how they perform the 3D-CT scanning. In our study, to simulate an intubating position, the patient was asked to open his mouth fully and extend his tongue as much as possible. Third, in our study, the patient’s airway was superimposed over translucent images of bones. This image allowed us to evaluate the airway more precisely, including its relationship to surrounding tissue. Noriaki Kanaya MD, PhD Akiyoshi Namiki MD, PhD

The Laryngeal Mask Airway Reliably Provides Rescue Ventilation in Cases of Unanticipated Difficult Tracheal Intubation Along with Difficult Mask Ventilation

The Laryngeal Mask Airway Reliably Provides Rescue Ventilation in Cases of Unanticipated Difficult Tracheal Intubation Along with Difficult Mask Ventilation

Video-Assisted Airway Management

Difficulties with tracheal intubation are a major cause for anaesthesia-related morbidity and mortality. Although pulsoximetry and capnometry are used for standard intubation monitoring, claims due to oesophageal intubations and difficult intubations remain still 6% for each in the ASA closed claims study project as 10 years ago (1). Furthermore, increasing failed intubation rates in obstetric anaesthesia have been reported and are a reason for great concern (2). Video-assisted airway management (VAAM) is a recently designed new concept for routine intubation monitoring and for management of the unanticipated difficult tracheal intubation.

The Laryngeal Mask Airway Reliably Provides Rescue Ventilation in Cases of Unanticipated Difficult Tracheal Intubation Along with Difficult Mask Ventilation

In 1995, our department of anesthesiology established an airway team to assist in treating unanticipated difficult endotracheal intubations and an airway quality im-provement (QI) form to document the use of emergency airway techniques in airway crises (laryngeal mask airway [LMA], flexible fiberoptic bronchoscopy, retrograde intubation [RI], transtracheal jet ventilation [TTJV], and cricothyrotomy). Over a 2-yr period, team members and staff anesthesiologists completed airway QI forms to document the smallest peripheral SpO2 during an airway crisis, the number of direct laryngoscopies (DL) performed before using an emergency airway technique, and the emergency airway technique that succeeded in rescue ventilation. Team members agreed to use the LMA as the first emergency airway technique to treat the difficult ventilation/difficult intubation scenario. A SpO2 value <or=to90% during mask ventilation defined difficult ventilation. Inability to perform tracheal intubation by DL defined difficult intubation. An increase in the SpO2 value >90% defined rescue ventilation. Review of airway QI forms from October 1, 1995 until October 1, 1997 revealed 25 cases of difficult ventilation/difficult intubation. Before airway rescue, the median SpO2 was 80% (range 50%-90%), and there were four median attempts at DL (range one to nine). The LMA had a success rate of 94% (95% confidence interval [CI] 77-100). Flexible fiberoptic bronchoscopy, TTJV, RI, and surgical cricothyrotomy had success rates of 50% (95% CI 0-100), 33% (95% CI 0-100), 100% (95% CI 37-100), and 100% (95% CI 37-100), respectively. LMA insertion as the first alternative airway technique was useful in dealing with unanticipated instances of simultaneous difficulty with mask ventilation and tracheal intubation. Implications: Twenty-five cases of simultaneous difficulty with mask ventilation and tracheal intubation occurred after the induction of general anesthesia during the study period. The laryngeal mask was used in 17 cases, and it provided rescue ventilation without complication in 94% of these cases (95% confidence interval 77-100). (Anesth Analg 1998;87:661-5)