The Trigeminocardiac Reflex and Dermatologic Surgery

Maxillomandibulocardiac reflex in a dog

Background

The trigeminocardiac reflex (TCR) is a brainstem reflex that may be observed in anaesthesia during surgical procedures stimulating the intracranial or peripheral portion of the trigeminal nerve. The peripheral TCR is divided into the oculocardiac reflex and the maxillomandibulocardiac reflex based on the affected sensory branches of the trigeminal nerve. In veterinary medicine the oculocardiac reflex has been described, however the maxillomandibulocardiac reflex has never been reported.

Case presentation

A 5-year-old male Epagneul Breton was presented for surgical management of an upper lip mass. During surgery, a sudden severe bradycardia and a decrease in systemic arterial blood pressure developed. The occurrence of a maxillomandibulocardiac reflex was suspected on the basis of the temporary link between surgical stimulation and haemodynamic changes. Three doses of atropine were given before starting a dopamine infusion due to lack of response. The dopamine infusion normalized heart rhythm and blood pressure. The dog recovered uneventfully and he was discharged 24 h later with a sinus rhythm and no sign of recurrence of arrhythmias.

Conclusion

The TCR is a rare but potentially life-threatening complication of procedures involving the sensory areas innervated by the three branches of the trigeminal nerve and it may cause bradycardia with hypotension. The use of a β1-adrenergic receptor agonist such as dopamine may be indicated in cases of a refractory response to the conventional treatment with atropine.

The clinical surrogate definition of the trigeminocardiac reflex: Development of an optimized model according to a PRISMA-compliant systematic review

BACKGROUND

The trigeminocardiac reflex (TCR) is defined as sudden onset of parasympathetic dysrhythmias including hemodynamic irregularities, apnea, and gastric hypermotility during stimulation of sensory branches of the trigeminal nerve. Since the first description of the TCR 1999, there is an ongoing discussion about a more flexible than the existing clinical definition. Aim of this work was to create a clinical surrogate definition through a systematic review of the literature.

METHODS

In this meta-analysis study, literature about TCR occurrences was, according to the Preferred Reporting Items for Systematic Reviews and Meta-Analysis statement, systematically identified through various search engines including PubMed (Medline), Embase (Ovid SP), and ISI Web of Sciences databases from January 2005 to August 2015. TCR was defined as a drop of heart rate (HR) below 60 bpm or 20% to the baseline. We extracted detailed data about hemodynamic changes and searched for connections between arterial blood pressure (BP) and HR changes during such episodes.

RESULTS

Overall 45 studies harboring 57 patients were included in the study but only 32 patients showed sufficient data for final analyze. HR showed a nonlinear behavior with a "tipping point" phenomena that differs in variance from the central/peripheral (20-30% drop) to ganglion (40-49% drop). BP showed a linear behavior with a "central limit" phenomena not differing in variance in the whole subgroup (30-39% drop). An analyzation of the correlation between BP and HR showed a trend to a linear correlation.

CONCLUSIONS

We can show for the first time that HR is the dominant variable in the TCR and present a new surrogate definition model. This model and the role of BP must be better investigated in further studies.

In-office vasovagal response after rhinologic manipulation

BACKGROUND

Advances in endoscopic sinus surgery have led to a greater number of in-office procedures away from the traditional operating room setting. Rhinologists acting independently of anesthesiologists must be prepared for potential complications, such as vasovagal response (VVR), that may arise during in-office rhinologic manipulations. In this study, we review our experience with this condition and discuss risk factors and a management algorithm for in-office VVR.

METHODS

A retrospective analysis at a large tertiary referral center was performed on all patients undergoing in-office endoscopic procedures with rhinologic manipulation between July 2008 and June 2012. A total of 4973 patients underwent in-office endoscopic procedures and 8 patients with VVR were identified. Demographic data, diagnosis, procedure performed, and outcomes were reviewed.

RESULTS

Eight patients out of 4973 (0.16%) experienced VVR during in-office endoscopic procedures. Seven (87.5%) of these 8 patients recovered from the VVR within 30 minutes and subsequently completed their scheduled procedure. One (12.5%) of the 8 patients did not fully recover after 30 minutes and was sent to the Emergency Department, where he was stabilized and subsequently discharged. The most common comorbidities in these 8 patients with VVR were hypercholesterolemia in 3 patients (37.5%), and hypertension and benign prostatic hyperplasia, each found in 2 patients (25.0%).

CONCLUSION

Although the incidence of VVR during rhinologic procedures is low, rhinologists should be familiar with this condition and be prepared for its management.