Analgesia Nociception Index Monitoring in Trigeminal Cardiac Reflex During Nasal Septoplasty (ANI)

Utility of Analgesia Nociception Index (ANI) Monitoring in Predicting and Preventing Trigeminal Cardiac Reflex During Nasal Septoplasty

This study aims to evaluate the utility of Analgesia Nociception Index (ANI) monitoring as a predictive and preventive tool for TCR during septoplasty. By comparing standard anesthetic monitoring with ANI-guided analgesia, this research seeks to determine whether maintaining optimal autonomic balance can reduce the incidence of trigeminal cardiac reflex (TCR) and improve intraoperative cardiovascular stability.

Study Overview

• Status: Not yet recruiting
• Conditions: ENT Disease

Detailed Description

Nasal septoplasty is among the most frequently performed otorhinolaryngological procedures and is generally regarded as safe. However, it may occasionally be complicated by autonomic reflexes, most notably the trigeminal cardiac reflex (TCR) . The TCR is a brainstem reflex triggered by stimulation of the trigeminal nerve or its branches, resulting in sudden parasympathetic activation manifested as bradycardia, hypotension, arrhythmias, or even cardiac arrest. Clinically, TCR is typically defined as a decrease in heart rate exceeding 20% from baseline following trigeminal stimulation .

The nasal septum is richly innervated by branches of the trigeminal nerve, particularly in the posterior septal region and near the sphenopalatine area. Surgical manipulation during septoplasty, including mucoperichondrial flap elevation, septal correction, and spur removal, can therefore precipitate TCR. Reported incidence rates of TCR during nasal surgery vary widely in the literature, ranging from approximately 15% to 25%, depending on surgical technique, anesthetic depth, and patient-related factors. Although most episodes are transient and reversible, unanticipated bradycardia can lead to hemodynamic instability and interruption of surgery, underscoring the importance of early detection and prevention .

Traditionally, anesthesiologists rely on conventional hemodynamic parameters such as heart rate and blood pressure to assess autonomic responses and anesthetic adequacy . However, these parameters represent relatively late manifestations of vagal activation. By the time a significant decrease in heart rate is observed, the trigeminal cardiac reflex has already occurred. Therefore, a monitoring modality capable of detecting early changes in autonomic balance before overt bradycardia develops would be of considerable clinical value .

The Analgesia Nociception Index (ANI) is a non-invasive monitoring tool derived from heart rate variability analysis, reflecting the balance between sympathetic and parasympathetic activity. ANI primarily reflects parasympathetic tone, with values ranging from 0 to 100. Higher values indicate parasympathetic predominance, whereas lower values suggest sympathetic activation or inadequate analgesia. Maintaining ANI values within a target range (commonly 50-70) has been proposed as a strategy to optimize intraoperative analgesia and autonomic stability.

Given that TCR is mediated by sudden parasympathetic overactivity, continuous ANI monitoring may provide an early warning signal of impending reflex activation . A sudden drop in ANI could theoretically precede the hemodynamic manifestations of TCR, allowing timely anesthetic or surgical interventions to prevent or attenuate the reflex. Despite its growing use in anesthesia practice, the role of ANI monitoring in predicting and preventing TCR during nasal septoplasty has not been adequately studied.

Data analysis will be carried out using SPSS (IBM SPSS Statistics) and/or R. Continuous variables will be expressed as mean ± standard deviation (SD) when normally distributed, or as median with interquartile range for nonnormally distributed data. Categorical variables will be summarized as frequencies and percentages. A p-value of less than 0.05 (two-tailed) will be considered statistically significant. Group comparisons will be conducted using: Independent samples t-test for normally distributed continuous data, Mann-Whitney U test for skewed continuous data, Chi-square test or Fisher's exact test for categorical data

• Study Type: Observational
• Enrollment (Estimated): 90

Contacts and Locations

• Study Contact: Name: Fatmaelzahraa Omar Bahr, lecture; Phone Number: 00201097356769; Email: drfatmabahr85@gmil.com
• Study Contact Backup: Name: Mohmed Ahmed Hamed, professor; Phone Number: 0020101050999736; Email: mah07@fayoum.edu.eg

Study Locations

• Egypt
  • Faiyum Governorate
    • Al Fayyum, Faiyum Governorate, Egypt, 63514
      • Fayoum univeristy hospital
      • Contact: Fatmaelzhraa Omar Omar, Lecture; Phone Number: 002010997356769; Email: drfatmabahr85@gmail.com
      • Contact: Mohaed Ahmed Hamed, professor; Phone Number: 00201010509736; Email: moh07@fayoum.edu.eg

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult
• Accepts Healthy Volunteers: No

• Sampling Method: Non-Probability Sample

Study Population

Adult patients scheduled for elective nasal septoplasty under general anesthesia will be enrolled.

Description

Inclusion Criteria:

• Age 18-60 years.
• American society of anesthesiologist physical status I-II
• Indicated for primary septoplasty.

Exclusion Criteria:

• Known cardiac arrhythmias or conduction disorders.
• Use of beta-blockers or antiarrhythmic medications.
• Previous nasal surgery and Combined nasal procedures.
• Inability to obtain reliable Analgesia Nociception Index readings.

Study Plan

How is the study designed?

Number of groups / cohorts

2

Cohorts and Interventions

Group / Cohort
Group A (Control Group; Standard monitoring including heart rate, non-invasive blood pressure, oxygen saturation, and bispectral index (BIS).
Group B (ANI Group); Standard monitoring plus continuous ANI monitoring, with intraoperative analgesia adjusted to maintain Analgesia Nociception Index ( ANI) values between 50 and 70

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Primary Outcome - Incidence of trigeminal cardiac reflex	Defined as a decrease in heart rate >20% from baseline during surgery.	3 hours

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Time interval between Analgesia Nociception Index drop and subsequent heart rate decrease (early warning window).	Time in minutes between occurrence of Analgesia Nociception Index drop and subsequent heart rate decrease	3 hours
Total intraoperative opioid consumption.	The amount in milligram of opioid consumption.	3 hours.
Incidence of hypotension or arrhythmias.	Decrease mean arterial pressure less than 60mmgh or occurrence of tachycardia or bradycardia.	3 hours

Collaborators and Investigators

• Sponsor: Fayoum University Hospital
• Investigators: Principal Investigator: Mohamed Ahmed Hamed, Professor, Fayoum University hospital; Study Director: Fatmaelzahraa Omar Bahr, Lecture, Fayoum University hospital; Study Chair: Mohamed Eid Khalil, Lecture, Fayoum University hospital

Publications and helpful links

General Publications

• Lapi D, Scuri R, Colantuoni A. Trigeminal Cardiac Reflex and Cerebral Blood Flow Regulation. Front Neurosci. 2016 Oct 20;10:470. doi: 10.3389/fnins.2016.00470. eCollection 2016.
• Lunardi G, Giombi F, Pace GM, Cerasuolo M, Spriano G, Malvezzi L. Measuring Nasal Airway Resistance to Personalize Surgery for Nasal Obstruction in OSA Patients. J Pers Med. 2025 Dec 8;15(12):608. doi: 10.3390/jpm15120608.
• Dadgarnia MH, Baradaranfar MH, Mazidi M, Azimi Meibodi SM. Assessment of Septoplasty Effectiveness using Acoustic Rhinometry and Rhinomanometry. Iran J Otorhinolaryngol. 2013 Spring;25(71):71-8.

Study record dates

Study Major Dates

• Study Start (Estimated): April 1, 2026
• Primary Completion (Estimated): April 1, 2027
• Study Completion (Estimated): May 1, 2027

Study Registration Dates

• First Submitted: February 21, 2026
• First Submitted That Met QC Criteria: February 21, 2026
• First Posted (Actual): February 27, 2026

Study Record Updates

• Last Update Posted (Actual): March 4, 2026
• Last Update Submitted That Met QC Criteria: March 2, 2026
• Last Verified: March 1, 2026

More Information

Terms related to this study

• Keywords: Analgesia Nociception Index; Septoplasty; Trigeminal Cardiac Reflex
• Additional Relevant MeSH Terms: Otorhinolaryngologic Diseases
• Other Study ID Numbers: R804

Drug and device information, study documents

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