Evidence-based Algorithm for the Expected Difficult Intubation (Expect-it)

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

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).

Study Overview

• Status: Completed
• Conditions: Airway Management; Intubation, Intratracheal
• Intervention / Treatment: Other: No intervention, observational study

Detailed Description

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'.

• Study Type: Observational
• Enrollment (Actual): 1282

Contacts and Locations

Study Locations

• Germany
  • Hamburg, Germany, 20246
    • University Medical Center Hamburg-Eppendorf

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years and older (Adult, Older Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

• Sampling Method: Non-Probability Sample

Study Population

Consecutive sampling: Adult patients that undergo ENT or OMS surgery in a tertiary care hospital who require tracheal intubation and consent to participate within two predefined study periods of at least 3 months.

Description

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)

Study Plan

How is the study designed?

Number of groups / cohorts

2

Cohorts and Interventions

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

What is the study measuring?

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
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
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
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

Collaborators and Investigators

• Sponsor: Universitätsklinikum Hamburg-Eppendorf
• Investigators: Study Chair: Christian Zöllner, MD, Universitätsklinikum Hamburg-Eppendorf; Study Chair: Antonia Zapf, PhD, Universitätsklinikum Hamburg-Eppendorf

Study record dates

Study Major Dates

• Study Start (Actual): May 1, 2021
• Primary Completion (Actual): January 29, 2022
• Study Completion (Actual): January 29, 2022

Study Registration Dates

• First Submitted: April 13, 2021
• First Submitted That Met QC Criteria: April 24, 2021
• First Posted (Actual): April 28, 2021

Study Record Updates

• Last Update Posted (Actual): March 2, 2022
• Last Update Submitted That Met QC Criteria: March 1, 2022
• Last Verified: March 1, 2022

More Information

Terms related to this study

• Keywords: Laryngoscopy; Laryngoscopes; Diagnostic Techniques, Respiratory System
• Other Study ID Numbers: 2021-10459-BO-ff

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No