Evidence-based Algorithm for the Expected Difficult Intubation

Study Overview
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Brief Summary
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The Expect-it study aims to accompany the development and clinical implementation process of a new algorithm for the management of expected difficult intubation. The new algorithm is designed to allocate patients to specific tracheal intubation techniques. After assessing the status quo (non-algorithm-based decision-making) the new algorithm-based allocation will be compared with this clinical standard within a confirmatory diagnostic accuracy study (post-implementation).

Detailed Description
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Difficult tracheal intubation is one of the major reasons for anesthesia-related adverse events. Patients undergoing ear, nose & throat (ENT) or oral and maxillofacial (OMS) surgery often require tracheal intubation for general anesthesia but are at increased risk for difficult tracheal intubation. Currently, existing preoperative tests for the prediction of difficult intubation show low diagnostic accuracy. Moreover, as the results of these prediction tests are not coupled with concrete treatment recommendations, they cannot be used targeted within preventive concepts. An evidence based rational algorithm for the management of expected difficult intubation has not been developed yet. It is unknown, if an algorithm-based allocation to an intubation approach might be advantageous compared with a non-algorithm-based allocation strategy. The Expect-it study aims to accompany the development and clinical implementation process of a new algorithm for the management of expected difficult intubation. This new algorithm is designed to provide an evidence-based decision-making tool for a rational pre-choice of tracheal intubation techniques, anesthetized intubation by direct laryngoscopy (DL) or videolaryngoscopy (VL) or awake tracheal intubation (ATI). In the first study phase the status quo (clinical standard, non-algorithm-based decision-making) will be assessed (three-month period with an approximated case number of up to 600 patients). The Expect-it algorithm will be implemented thereafter. Between both study phases, the algorithm will be updated (based on the findings of the first phase), sensitivity and specificity of the clinical standard will be calculated, sample size will critically be appraised and readjusted (approximately 600 within at least three months), if appropriate. The second study phase is a confirmatory diagnostic accuracy study for the new algorithm with a single test study design, that aims to proof, if the new Expect-it algorithm is superior or at least non-inferior to the clinical standard, defined as superiority in either the specificity or sensitivity and non-inferiority in the other co-primary endpoint in each domain (ATI, DL, VL) (pre-planned preliminary analysis of the first study phase; IRB amendment 2021-10459_2-BO-ff, December 3, 2021). Sensitivity and specificity are considered co-primary endpoints. Study planning and conduction is in accordance with the Standards for Reporting Diagnostic accuracy studies (STARD) statement. The Expect-it study will further include two surveys among anesthetist in the study center in order to evaluate challenges and obstacles associated with the implementation process and possible clinical implications of the algorithm. An additional analysis will be performed to test a core data set for an 'anesthesia alert card'.

Official Title
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Development and Implementation of an Evidence-based Clinical Algorithm for the Expected Difficult Intubation

Conditions
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Airway Management, Intubation, Intratracheal

Intervention / Treatment
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* Other: No intervention, observational study


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Patients undergoing ENT or OMS surgery that require general anesthesia with tracheal intubation (either DL, VL or ATI) Age ≥ 18 years Exclusion Criteria: Denial of consent Planned intubation technique is not designated in the study protocol as it differs from either DL, VL, ATI (e.g. primary tracheotomy or rigid bronchoscopy)

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Clinical standard (first study phase)<br>Current clinical standard, non-algorithm-based decision-making (prior to implementation of the algorithm) | Other: No intervention, observational study<br>* Exposure of interest: clinical implementation of an algorithm<br>|
| Algorithm-based allocation (second study phase)<br>New algorithm-based allocation to an intubation technique (after implementation of the algorithm) | Other: No intervention, observational study<br>* Exposure of interest: clinical implementation of an algorithm<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| First phase: sensitivity and specificity (co-primary endpoints) of the clinical standard | Clinical assessment | 3 months | 
| Second phase: sensitivity and specificity (co-primary endpoints) of 'ATI recommendation' by the algorithm vs. 'VL/DL' | Clinical assessment | 3 months | 
| Second phase: sensitivity and specificity (co-primary endpoints) of 'DL recommendation' by the algorithm vs. 'VL/ATI' | Clinical assessment | 3 months | 
| Second phase: sensitivity and specificity (co-primary endpoints) of 'VL recommendation' by the algorithm vs. 'DL/ATI' | Clinical assessment | 3 months | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Post-intubation recommendation for an intubation method | Recommendation of the responsible anesthetist | 1 hour | 
| Post-intubation recommendation for an anesthesia alert card | Recommendation of the responsible anesthetist | 1 hour | 
| Post-intubation diagnosis 'difficult intubation' | Rating of the responsible anesthetist | 1 hour | 
| Post-intubation diagnosis 'difficult face-mask-ventilation' | Rating of the responsible anesthetist | 1 hour | 
| Classification of intubation difficulty (VIDIAC classification) | Rating between -1 and 5 points | 1 hour | 
| Best glottic view | Grading according to 'Percentage of Glottis Opening' (POGO) | 1 hour | 
| Best glottic view | Grading according to the Cormack Lehane classification (I-IV) | 1 hour | 
| First pass success rate | Percentage of successful intubations with one attempt | 1 hour | 
| Overall success rate of the first choice technique | Percentage of successful intubation without transition to another technique | 1 hour | 
| Number of attempts | Total number of attempts until airway established | 1 hour | 
| Intubation time | Time to successful tracheal intubation | 1 hour | 
| Lowest oxygen saturation | Measured with pulse oxymetry during anesthesia induction | 1 hour | 
| Overall intubation difficulty, ease of intubation, quality of visualization | Subjective ratings on visual analogue scales (0 to 100 with 0 being the best) | 1 hour | 
| Airway-related adverse events | Laryngospasm, bronchospasm, larynx trauma, airway trauma, soft tissue trauma, oral bleeding, edema, dental damage, corticosteroid application, accidental esophageal intubation, aspiration, hypotension or hypoxia | 1 hour | 
| Patient discomfort, satisfaction, symptoms | Clinical assessment during follow-up | 12 hours | 
| Clinical evaluation of a core dataset 'anesthesia alert card' | Rating of various anesthetist | 10 months | 
| Quality of care of the current clinical standard and the effects of algorithm implementation | Survey among anesthetist | 7 months | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Laryngoscopy, Laryngoscopes, Diagnostic Techniques, Respiratory System