Study on the Decision Support System of Difficult Airway Evaluation

Study Overview
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Brief Summary
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Based on the evaluation of preoperative physical indicators and radiologic indicators of cervical surgery, this study puts forward effective indicators for predicting difficult airway before operation, and establishes a comprehensive decision support system of difficult airway evaluation, so as to provide a theoretical basis for the early warning of difficult airway before cervical spondylosis surgery.

Detailed Description
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In the past, the evaluation of difficult airway mainly depended on physical indicators, but the internal structure of airway could not be found by appearance inspection. Therefore, unexpected emergency airway often appeared in clinical work, which seriously affected medical safety. In this study, the specific mechanism of difficult laryngoscopy in patients undergoing cervical spondylosis surgery is clarified by the combination of the physical indicators and radiologic indicators. On this basis, we will establish the preoperative airway evaluation system for cervical spondylosis surgery, optimize the standardized process of preoperative airway evaluation, and accurately screen out high-risk patients.

Official Title
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Department of Anesthesiology, Peking University Third Hospital, Associate Chief Physician; M.D.

Conditions
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Difficult Airway

Intervention / Treatment
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* Procedure: endotracheal intubation


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: patients of ASA I-III scheduled for elective surgery for cervical spondylosis under general anesthesia with tracheal intubation Exclusion Criteria: patients with cervical spine instability oropharyngeal mass airway disease preoperative imaging data were incomplete refuse to sign informed consent

Ages Eligible for Study
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Minimum Age: 20 Years
Maximum Age: 80 Years

Sexes Eligible for Study
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All

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| difficult laryngoscopy group<br>Cormack-Lehane (C-L) scale: class III-IV | Procedure: endotracheal intubation<br>* all patients will receive laryngoscopy and endotracheal intubation<br>|
| easy laryngoscopy group<br>Cormack-Lehane (C-L) scale: class I-II | Procedure: endotracheal intubation<br>* all patients will receive laryngoscopy and endotracheal intubation<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Cormack-Lehane (CL) classification | describe laryngeal view during direct laryngoscopy | During induction | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| X1(X-ray indicators) | distance between the temporomandibular joint and tip of the upper incisors | During review the X-ray image | 
| X2(X-ray indicators) | perpendicular distance from the hard palate to the tip of the upper incisors | During review the X-ray image | 
| X3(X-ray indicators) | length of the mandibular body | During review the X-ray image | 
| X4(X-ray indicators) | vertical distance from the highest point of the hyoid bone to the mandibular body | During review the X-ray image | 
| X5(X-ray indicators) | distance from the antero-inferior border of the fourth cervical vertebra to the antero-superior border of the ﬁrst cervical vertebra | During review the X-ray image | 
| X6(X-ray indicators) | atlanto-occipital gapantero-superior border of the ﬁrst cervical vertebra | During review the X-ray image | 
| X7(X-ray indicators) | horizontal distance from the highest point of the hyoid bone to the border of the nearest cervical vertebra | During review the X-ray image | 
| X8(X-ray indicators) | distance between the spinous processes of the ﬁrst cervical vertebra and the second cervical vertebra | During review the X-ray image | 
| A1 (X-ray indicators) | the angle between a line passing through the bottom of second cervical vertebra and a line passing through the bottom of sixth cervical vertebra in the neutral/ extension position | During review the X-ray image | 
| Hp-h (CT/MRI indicators) | the distance from back end of the hard palate to the top of hyoid | During review the CT/MRI image | 
| Ht (CT/MRI indicators) | the height of the tongue base, along Hp-h from the tongue to the top of hyoid | During review the CT/MRI image | 
| Dt-p (CT/MRI indicators) | the distance from the back end of tongue to posterior pharyngeal wall | During review the CT/MRI image | 
| Dt (CT/MRI indicators) | the distance from the back end of tongue to Hp-h | During review the CT/MRI image | 
| S (CT/MRI indicators) | the central sectional area of the tongue base behind Hp-h | During review the CT/MRI image | 
| W (CT/MRI indicators) | the maximal width of the tongue base | During review the CT/MRI image | 
| V (CT/MRI indicators) | volume of the tongue base | During review the CT/MRI image | 
| Rs (CT/MRI indicators) | Rs= S/( Hp-h* Dt-p); Rv =V/( Hp-h* Dt-p*W) | During review the CT/MRI image | 
| MRI1 (MRI indicators) | distance between the base of the tongue and the posterior pharyngeal wall | During review the CT/MRI image | 
| MRI2 (MRI indicators) | distance between the epiglottis and the posterior pharyngeal wall | During review the CT/MRI image | 
| MRI3 (MRI indicators) | distance between the uvula and the posterior pharyngeal wall | During review the CT/MRI image | 
| MRI4 (MRI indicators) | distance between the vocal cords and the posterior pharyngeal wall | During review the CT/MRI image | 
| MRI5 (MRI indicators) | length of the epiglottis | During review the CT/MRI image |