Vasovagal syncope in heart transplant patients during dental surgery

Syncope in Dental Practices: A Systematic Review on Aetiology and Management

INTRODUCTION

This systematic review aimed to give an overview of the current evidence surrounding the aetiology and management in terms of treatment and prevention of syncope in dental practices. Alongside the occurrence, the practitioner's competence, and the association between syncope and local anaesthetics were discussed.

METHODS

An electronic search in EMBASE, Web of Science, PubMed, Cochrane databases and a hand search were performed by 2 independent reviewers to identify studies up to November 2019. Eligibility criteria were applied and relevant data was extracted. Inclusion criteria covered all types of dental treatment under local anaesthesia or conscious sedation performed by a wide range of oral health care workers in their practices. Risk of bias of the included studies was assessed using the methodological tools recommend by Zeng et al.¹ No restrictions were made to exclude papers from qualitive analysis based on risk of bias assessment.

RESULTS

The search yielded a total of 18 studies for qualitative analysis. With the exception of one prospective cohort study, all articles were considered having a high risk of bias. Meta-analysis showed that dentists encountered on average 1.2 cases of syncope per year. The male gender (RR = 2.69 [1.03, 7.02]), dental fear (RR = 3.55 [2.22, 5.70]), refusal of local anaesthesia in non-acute situations (OR = 12.9) and the use of premedication (RR = 4.70, [1.30, 16.90]) increased the risk for syncope. Treatment and prevention were underreported as both were solely discussed in one study. The supine recovery position with raised legs and oxygen administration (15l/min) was presented as an effective treatment. The Medical Risk-Related History (MRRH) system was proposed as prevention protocol, yet this protocol was ineffective in reducing incidence rates (p = 0.27). The majority of dentists (79.2%) were able to diagnose syncope, yet most (86%) lacked the skills for appropriate treatment. Only 57,6% of dental practices were equipped with an oxygen cylinder.

CONCLUSIONS

Syncope is the most common emergency in dental practices. Nonetheless, the vast majority of dentists do not seem competent nor prepared to manage this emergency. Psychogenic factors seem to play an important role in provoking syncope. Placing the patient in a supine reclined position with raised legs in combination with the administration of oxygen seems effective for regaining consciousness. Although valuable in many aspects, risk assessment by medical history taking is not proven to result in fewer episodes. The strength of these conclusions is low based on GRADE guidelines.².

Diagnostic and therapeutic approach to cardioinhibitory reflex syncope: A complex and controversial issue

Syncope is defined as a transient loss of consciousness due to global cerebral hypoperfusion and is one of the leading causes of emergency department admission. The initial approach should focus on excluding non-syncopal causes for loss of consciousness and risk stratification for cardiac cause, in order to ensure an appropriate etiological investigation and therapeutic approach. Vasovagal syncope (VVS), the most common type of syncope, should be assumed once other causes are excluded. Pathophysiologically, the vasovagal reflex is the result of a paradoxical autonomic response, leading to hypotension and/or bradycardia. VVS has not been shown to affect mortality, but morbidity may be considerable in those with recurrent syncopal episodes. The management of VVS includes both non-pharmacological and pharmacological measures that act on various levels of the reflex arc that triggers the syncopal episode. However, most are of uncertain benefit given the scarcity of high-quality supporting evidence. Pacemaker therapy may be considered in recurrent refractory cardioinhibitory reflex syncope, for which it is currently considered a robust intervention, as noted in the European guidelines. Non-randomized and unblinded studies have shown a potential benefit of pacing in recurrent VVS, but double-blinded randomized controlled trials have not consistently demonstrated positive results. We performed a comprehensive review of the current literature and recent advances in cardiac pacing and pacing algorithms in VVS, and discuss the diagnostic and therapeutic approach to the complex patient with recurrent VVS and reduced quality of life.

Syncope due to Autonomic Dysfunction: Diagnosis and Management

Syncope is one of several disorders that cause transient loss of consciousness. Cerebral hypoperfusion is the proximate cause of syncope. Transient or fixed autonomic nervous system dysfunction is a major contributor in many causes. A structured approach to the evaluation of syncope allows for more effective therapy.

Concepts of scientific integrative medicine applied to the physiology and pathophysiology of catecholamine systems

This review presents concepts of scientific integrative medicine and relates them to the physiology of catecholamine systems and to the pathophysiology of catecholamine-related disorders. The applications to catecholamine systems exemplify how scientific integrative medicine links systems biology with integrative physiology. Concepts of scientific integrative medicine include (i) negative feedback regulation, maintaining stability of the body's monitored variables; (ii) homeostats, which compare information about monitored variables with algorithms for responding; (iii) multiple effectors, enabling compensatory activation of alternative effectors and primitive specificity of stress response patterns; (iv) effector sharing, accounting for interactions among homeostats and phenomena such as hyperglycemia attending gastrointestinal bleeding and hyponatremia attending congestive heart failure; (v) stress, applying a definition as a state rather than as an environmental stimulus or stereotyped response; (vi) distress, using a noncircular definition that does not presume pathology; (vii) allostasis, corresponding to adaptive plasticity of feedback-regulated systems; and (viii) allostatic load, explaining chronic degenerative diseases in terms of effects of cumulative wear and tear. From computer models one can predict mathematically the effects of stress and allostatic load on the transition from wellness to symptomatic disease. The review describes acute and chronic clinical disorders involving catecholamine systems-especially Parkinson disease-and how these concepts relate to pathophysiology, early detection, and treatment and prevention strategies in the post-genome era.

Neurocardiology: therapeutic implications for cardiovascular disease

The term "neurocardiology" refers to physiologic and pathophysiological interplays of the nervous and cardiovascular systems. This selective review provides an update about cardiovascular therapeutic implications of neurocardiology, with emphasis on disorders involving primary or secondary abnormalities of catecholamine systems. Concepts of scientific integrative medicine help understand these disorders. Scientific integrative medicine is not a treatment method or discipline but a way of thinking that applies systems concepts to acute and chronic disorders of regulation. Some of these concepts include stability by negative feedback regulation, multiple effectors, effector sharing, instability by positive feedback loops, allostasis, and allostatic load. Scientific integrative medicine builds on systems biology but is also distinct in several ways. A large variety of drugs and non-drug treatments are now available or under study for neurocardiologic disorders in which catecholamine systems are hyperfunctional or hypofunctional. The future of therapeutics in neurocardiology is not so much in new curative drugs as in applying scientific integrative medical ideas that take into account concurrent chronic degenerative disorders and interactions of multiple drug and non-drug treatments with each other and with those disorders.

Hypotensive bradycardic events during shoulder arthroscopic surgery under interscalene brachial plexus blocks

Sudden, profound hypotensive and bradycardic events (HBEs) have been reported in more than 20% of patients undergoing shoulder arthroscopy in the sitting position. Although HBEs may be associated with the adverse effects of interscalene brachial plexus block (ISBPB) in the sitting position, the underlying mechanisms responsible for HBEs during the course of shoulder surgery are not well understood. The basic mechanisms of HBEs may be associated with the underlying mechanisms responsible for vasovagal syncope, carotid sinus hypersensitivity or orthostatic syncope. In this review, we discussed the possible mechanisms of HBEs during shoulder arthroscopic surgery, in the sitting position, under ISBPB. In particular, we focused on the relationship between HBEs and various types of syncopal reactions, the relationship between HBEs and the Bezold-Jarisch reflex, and the new contributing factors for the occurrence of HBEs, such as stellate ganglion block or the intraoperative administration of intravenous fentanyl.

Syncope in the elderly

Syncope is common and costly especially in the elderly. Presentation and prevalence may be different compared with the young. Etiologies can be difficult to confirm but it is not a hopeless morass. The history, physical exam, and ECG have the greatest utility. Additional studies should be used sparingly and based on the initial data. Successful response to treatment is difficult to predict.

New insights into the mechanism of neurally mediated syncope

OBJECTIVE

To determine the role of the cerebral cortex in neurally mediated syncope, the electroencephalograms (EEG) of patients recorded during head up tilt table test were analysed.

DESIGN

Retrospective study.

SETTING

University hospital.

PATIENTS

18 patients with syncope or near syncope underwent head up tilt table test with simultaneous ECG and EEG monitoring.

METHODS

Standard 70 degrees tilt table test was done with simultaneous ECG and EEG monitoring. EEG waveforms were analysed by both visual inspection and spectral analysis.

RESULTS

6 of 18 patients (33%) had a positive tilt table test. Before syncope slow waves increased in patients with a positive test. In addition, five of six tilt positive patients (83%) had slow wave activity that lateralised to the left side of the brain (mean (SD) 822 (724) v 172 (215) micro V(2), p < 0.05), while none of the tilt negative patients exhibited lateralisation (24 (15) v 26 (19) micro V(2), NS). Spectral analysis showed that the lateralisation occurred in the delta frequency. The lateralisation preceded the event by 5-56 seconds (18 (21) seconds).

CONCLUSIONS

EEG activity lateralises to the left hemisphere of the brain before syncope. The lateralisation precedes syncope and is associated with the onset of bradycardia, hypotension, and clinical symptoms. These findings suggest that the central nervous system may have a role in neurally mediated syncope.

Periodontal management of patients with cardiovascular diseases

Periodontists are often called upon to provide periodontal therapy for patients with a variety of cardiovascular diseases. Safe and effective periodontal treatment requires a general understanding of the underlying cardiovascular diseases, their medical management, and necessary modifications to dental/periodontal therapy that may be required. In this informational paper more common cardiovascular disorders will be discussed and dental management considerations briefly described. This paper is intended for the use of periodontists and members of the dental profession.