Intubation-induced Decrease in Heart Rate as an Indicator for Intraoperative Bradycardia

Study Overview
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Brief Summary
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This prospective observational study aims to determine, if an tracheal intubation-related decrease in heart rate is associated with intraoperative reflex bradycardia in patients undergoing microlaryngoscopy (MLS) in general anesthesia.

Detailed Description
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Small studies and case series reported precipitous bradycardia or even asystole due to reflex vagal activity during tracheal intubation and/or laryngoscopy attributable to a so called laryngocardiac reflex (reflex bradycardia); however, larger systematic trials are still lacking. For the purpose of MLS, ENT surgeons frequently apply suspension laryngoscopy (Kleinsasser laryngoscope) in order to visualize the glottis and to enable surgery. Severe bradycardia has been reported during MLS that has been suspected to be induced by reflex vagal activity possibly promoted by the superior laryngeal nerve. It is still unknown, which patients are at risk for relevant intraoperative bradycardia and moreover, which patients might benefit from preemptive measures such as prophylactic application of positive chronotropic drugs like atropine sulfate, epinephrine or glycopyrrolate. Predictive factors for MLS-induced intraoperative bradycardia have not systematically been investigated yet. In particularly, it is unknown, if patients that present with a preoperative tracheal intubation-related decrease in heart rate have a predisposition for intraoperative reflex bradycardia during MLS. This prospective observational study aims to determine, if an tracheal intubation-related decrease in heart rate is associated with intraoperative reflex bradycardia in patients undergoing microlaryngoscopy (MLS) in general anesthesia. Moreover, if we find a positive association, we further aim to determine the predictive value of intubation-relatd bradycardia.

Official Title
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Tracheal Intubation-induced Decrease in Heart Rate as an Indicator for Intraoperative Bradycardia During Microlaryngoscopy -a Prospective Observational Trial

Conditions
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Airway Management, Tracheal Intubation, Heart Rate

Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Patients requiring general anesthesia with tracheal intubation for elective MLS Age ≥ 18 Exclusion Criteria: Pregnant or breastfeeding women Confirmed indications for awake fiberoptic intubation Planned endotracheal intubation without deep anesthesia or neuromuscular blocking agents (e.g. awake videolaryngoscopy) Patients at risk for pulmonary aspiration who qualify for rapid sequence induction Cardiac pacemaker Atrial fibrillation Denial of consent

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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What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Intraoperative decrease of the heart rate | Continuous intraoperative ECG heart rate measurement (sample rate 1000 hz) | 1 hour | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Intraoperative asystolia | Continuous intraoperative ECG QRS-complex detection (sample rate 1000 hz) | 1 hour | 
| Application of atropine sulfate | Intraoperative application of atropine sulfate by the responsible anesthetist (yes/no) | 1 hour | 
| Application of positive inotropic drugs | Intraoperative application of other positive inotropic drugs such as epinephrine by responsible anesthetist (yes/no) | 1 hour | 
| Cardiac arrhythmias | Continuous intraoperative ECG arrhythmia detection and labeling (sample rate 1000 hz) | 1 hour | 
| Hypotension | Intraoperative blood pressure measurement | 1 hour | 
| Application of catecholamines or vasoactive drugs | Intraoperative application of catecholamines or vasoactive drugs by responsible anesthetist (yes/no) | 1 hour | 
| Adverse cardiocirulatory events | Intraoperative adverse cardiocirulatory events docuimented by the responsible anethetist | 1 hour | 
| PACU stay | Length of stay in the postanesthesia care unit (PACU) | 8 hours | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Laryngoscopy, Bradycardia, Microlaryngoscopy