A Prospective Observational Study on the Association of Lingual Retraction With Hemodynamic Parameter Changes in Patients Receiving Dental Procedures Under General Anesthesia

Stimulation of both the central and peripheral branches of the trigeminal nerve can lead to clinically significant hemodynamic changes. The trigeminocardiac reflex (TCR), a brainstem-mediated reflex mechanism triggered by such stimulations, causes sudden and marked decreases in heart rate and arterial blood pressure. This reflex may result in hemodynamic instability during surgical interventions and, in rare cases, can precipitate severe cardiac complications including cardiac arrest.

While TCR is more commonly observed during ophthalmic, craniofacial, and skull base surgeries, it may also occur during dental procedures. Stimulation of the peripheral branches of the lingual nerve, such as during lingual retraction, has been associated with cardiovascular side effects like bradycardia. This phenomenon reflects systemic hemodynamic responses resulting from trigeminal nerve stimulation.

The literature reports significant drops in heart rate and arterial pressure due to TCR during common dental procedures such as tooth extraction and implant surgery. Notably, sudden decreases of 10-20% in blood pressure are considered clinically relevant indicators of TCR. Additionally, hemodynamic changes potentially related to this reflex have been documented during endodontic treatments, particularly in cases of irreversible pulpitis. Thus, stimulation of the dental branches of the trigeminal nerve may trigger TCR during dental procedures, leading to systemic hypotension.

In conclusion, TCR triggered by trigeminal nerve stimulation is an important hemodynamic reflex encountered during surgical and dental interventions. Early recognition and appropriate preventive measures are critical to mitigating potential cardiac risks. Clinical procedures should consider patients' susceptibility to such reflexes in planning and management.

This study aims to investigate the incidence of trigeminocardiac reflex triggered primarily by lingual retraction, and secondarily by dental procedure type, tooth location, patient age, and duration of general anesthesia in **pediatric** patients undergoing dental surgeries under general anesthesia. **Statistical Revision & Amendment [March 2026]:** The study protocol has been revised to focus exclusively on the pediatric population (aged 2-18 years), in line with the primary research objective. The initial design included both adult (n=50) and pediatric (n=50) cohorts; however, the pediatric cohort was prioritized due to its greater susceptibility to trigeminocardiac reflex (TCR) events, and practical considerations regarding adult enrollment feasibility. Consequently, the adult arm was discontinued. This modification was reviewed and formally approved by the Kırıkkale University Non-Interventional Research Ethics Committee in its meeting on March 11, 2026 (2026/04 meeting number), referencing the original approval of the study (2025/12 meeting number, decision 2025.09.04). The primary outcome and data collection methodology from the original protocol were preserved, while the previously planned secondary outcome comparing adult and pediatric cohorts was removed. No other aspects of study design, observational methods, or ethical standards were modified.