Vasovagal Reactions during Interventional Pain Management Procedures-A Review of Pathophysiology, Incidence, Risk Factors, Prevention, and Management.

Vasovagal reactions are a benign but common outcome of interventional pain management procedures that can negatively impact patient care, including aborted procedures and fear of future procedures that would otherwise help the patient. Research has been done on the incidence, risk factors, and management of vasovagal reactions resulting from such procedures, but less is known about how to prevent these reactions from occurring. In this paper, we present a literature review of the pathophysiology, incidence, risk factors, prevention, and management of vasovagal reactions during interventional pain management procedures, with an emphasis on the relative lack of research and conflicting advice on preventive measures. We found that moderate sedation and anxiolytics have been used prophylactically to prevent vasovagal reactions, but their side-effect profiles prevent them from being used commonly. Less studied is the prophylactic administration of antimuscarinics and IV fluids, despite the potential benefit of these measures and relatively low side-effect profile. We explore these topics here and offer advice for future research to fill the gaps in our knowledge.

The role of clinical assessment and electrophysiology study in Brugada syndrome patients with syncope.

BACKGROUND: Cardiogenic syncope in Brugada syndrome (BrS) increases the risk of major events. Nevertheless, clinical differentiation between cardiogenic and vasovagal syncope can be challenging. We characterized the long-term incidence of major events in a large cohort of BrS patients who presented with syncope. METHODS: From a total of 474 patients, syncope was the initial manifestation in 135 (28.5%) individuals (43.9 ±â€¯13.9 years, 71.1% male). The syncope was classified prospectively as cardiogenic, vasovagal, or undefined if unclear characteristics were present. Clinical, electrocardiographic, genetic, and electrophysiologic features were analyzed. Cardiogenic syncope, sustained ventricular arrhythmias, and sudden death were considered major events in follow-up. RESULTS: In 66 patients (48.9%), the syncope was cardiogenic; in 51 (37.8%), vasovagal and in 18 (13.3%); undefined. The electrophysiology study (EPS) inducibility was more frequent in patients with cardiogenic syncope and absent in all patients with undefined syncope (28 [53.8%] vs 5 [12.2%] vs 0 [0%]; P < .01). During follow-up (7.7 ±â€¯5.6 years), only patients with cardiogenic syncope presented major events (16 [11.9%]). Among patients with inducible EPS, 7 (21.2%) presented major events (P = .04). The negative predictive value of the EPS for major events was 92.4%. The incidence rate of major events was 2.6% person-year. Parameters associated with major events included cardiogenic syncope (hazard ratio [HR] 6.3; 95% CI 1.1-10.4; P = .05), spontaneous type 1 electrocardiogram (HR 3.7; 95% CI 1.3-10.5; P = .01), and inducible EPS (HR 2.8; 95% CI 1.1-8.8; P = .05). CONCLUSIONS: An accurate syncope classification is crucial in BrS patients for risk stratification. In patients with syncope of unclear characteristics, the EPS may be helpful to prevent unnecessary implantable cardioverter defibrillators.

Risk factors for complications in donors at first and repeat whole blood donation: a cohort study with assessment of the impact on donor return.

BACKGROUND: First-time donation is among recognised risk factors for vasovagal reactions to blood donation and reactions are known to reduce donor return. We assessed associations between potential risk factors and vasovagal reactions and needle-related complications in first-time whole blood donation in comparison to repeat donation and analysed the impact of complications on donor return. MATERIALS AND METHODS: We performed a cohort study on whole blood donations in The Netherlands from 1/1/2010 to 31/12/2010 using data extracted from the blood service information system. Donation data up to 31/12/2011 were used to ascertain donor return. RESULTS: In 2010 28,786 donors made first whole blood donations and there were 522,958 repeat donations. Vasovagal reactions occurred in 3.9% of first donations by males and 3.5% of first donations by females compared to in 0.2% and 0.6%, respectively, of repeat donations. Associations of vasovagal reactions with other factors including age, body weight, systolic and diastolic blood pressure were similar in first-time and repeat donors. Needle-related complications occurred in 0.2% of male and 0.5% of female first-time donations and in 0.1% and 0.3%, respectively, of repeat donations. Among first-time donors, the return rate within 1 year was 82% following an uncomplicated first donation, but 55% and 61% following vasovagal reactions and needle-related complications, respectively; the corresponding percentages among repeat donors were 86%, 58% and 82%. DISCUSSION: Among first-time donors, females suffered less than males from vasovagal reactions. Other risk factors had similar associations among first-time and repeat donors. Vasovagal reactions and needle-related complications in both first-time and repeat donors are followed by reduced donor return.

Epidemiology and economic impact of cardiac syncope in western countries.

This article updates our current understanding of the epidemiology and economic impact of syncope in western countries. Unfortunately, both of these aspects of syncope are inadequately understood; in part the problem is due to the difficulty in public health data separating 'true syncope' from conditions that cause other forms of transient loss of consciousness. However, in certain respects, the epidemiology of syncope is becoming clearer. Similarly, we have come to understand that the economic impact of syncope is substantial and is much larger than is necessary, primarily because management, especially excessive hospitalization, often remains suboptimal.

The changing face of orthostatic and neurocardiogenic syncope with age.

AIM: Reports of the outcomes of syncope assessment across a broad spectrum of ages in a single population are scarce. It is our objective to chart the varying prevalence of orthostatic and neurocardiogenic syncope (NCS) as a patient ages. METHODS: This was a retrospective study. All consecutive patients referred to a tertiary referral syncope unit over a decade were included. Patients were referred with recurrent falls or orthostatic intolerance. Tilt tests and carotid sinus massage (CSM) were performed in accordance with best practice guidelines. RESULTS: A total of 3002 patients were included (1451 short tilt, 127 active stand, 1042 CSM and 382 prolonged tilt). Ages ranged from 11 to 91 years with a median (IQR) of 75 (62-81) years. There were 1914 females; 1088 males. Orthostatic hypotension (OH) was the most commonly observed abnormality (test positivity of 60.3%). Those with OH had a median (IQR) age of 78 (71-83) years. Symptomatic patients were significantly younger than asymptomatic (P = 0.03). NCS demonstrated a bimodal age distribution. Of 194 patients with carotid sinus hypersensitivity, the median age (IQR) was 77 (68-82) years. Those with vasovagal syncope (n = 80) had a median (IQR) age of 30 (19-44) years. There were 57 patients with isolated postural orthostatic tachycardia syndrome. Of the total patients, 75% were female. They had a median (IQR) age of 23 (17-29) years. CONCLUSION: We have confirmed, in a single population, a changing pattern in the aetiology of syncope as a person ages. The burden of disease is greatest in the elderly.

Recent history of vasovagal syncope in a young, referral-based population is a stronger predictor of recurrent syncope than lifetime syncope burden.

INTRODUCTION: accurate selection of patients for vasovagal syncope studies requires strong risk stratification and knowledge of the natural history of syncope. We aimed to test the hypothesis that recent history of vasovagal syncope compared to distant history better predicts subsequent recurrence of syncope. METHODS AND RESULTS: in all, 208 subjects with a positive tilt test and ≥ 3 lifetime syncope spells were followed for 1 year. Syncope episodes in the preceding year and total historical spells were compared for their ability to predict a syncope recurrence using the criteria of optimal statistical significance, best linear separation of risk populations, and impact on power calculations. The number of vasovagal syncope spells in the preceding year better predicted syncope recurrence when compared to total number of historical spells (likelihood ratio statistic 28.4, P < 0.0001; versus 20.4, P = 0.001), and showed a substantial effect as the number of syncope events increased. For example, syncope recurred in 22% of those with <2 spells in the previous year compared to 69% in those with >6 spells. A history of no syncope compared to any syncope in the preceding year was associated with a 1-year probability of 7% versus 46% for syncope recurrence. A study designed to detect a 50% decrease in syncope recurrence at P = 0.05 with 80% power would require 159 patients with at least 3 lifetime spells, and only 108 patients with at least 3 spells in the previous year. CONCLUSIONS: the number of syncope events in the year preceding clinical evaluation is the best predictor of syncope recurrence.

[Orthostatic intolerance--prevalence, diagnostic management and its significance for occupational medicine]. / Orthostatische Intoleranz--Prävalenz, Diagnostik und die Bedeutung für die Arbeitsmedizin.

OBJECTIVE: Orthostatic intolerance (OI) is a syndrome which is characterised by headache, concentration difficulties, palpitation of the heart, dizziness associated with postural tachycardia and plasma norepinephrine concentrations that are disportionately high in upright posture. OI hitherto can only be diagnosed by a tilt table examination with high expenditure. In this paper we examine the reliability and validity of a questionnaire as a screening instrument for OI. METHODS: We studied 138 young males (mean age 21.6 years) from the military service. After a medical check and filling in the questionnaire, the participants underwent a tilt table test. The questionnaire consisted of 10 items registering presence and frequency of typical OI-symptoms. RESULTS: 104 probands showed a normal tilt table test. OI was diagnosed in 14 probands, orthostatic hypotension (OH) in 6 and postural orthostatic tachycardia syndrome (POTS) in 14. The participants with OI scored significantly higher in the questionnaire than the normal subjects: The mean score of the OI group was 22.6, the normal participants had a mean score of 3.9. Participants with POTS had a mean score of 13.5 and subjects with OH had a mean score of 17.0. CONCLUSIONS: We were able to establish a short questionnaire as a reliable and valid screening instrument for OI. Usage of this questionnaire can simplify enormously the diagnostic management of patients with suspected OI.

Vasovagal syncope in emergency room patients: analysis of a metropolitan area registry.

The aim of this study was to assess the epidemiology of syncope in unselected patients referred to an emergency room and eventually admitted to the clinical wards to perform a complete work-up, and to analyze the costs of hospitalization. The clinical charts of all patients referred for all causes to the emergency rooms of three hospitals in the Florence area during the year 2000 and of all patients admitted from the emergency rooms to the clinical wards with a diagnosis of lone-related (vasovagal) or disease-related syncope were revised. A total of 1,290 (3.36%) cases of syncope out of 38,330 presentations were registered; among these, 702 cases (1.83% of all presentations, 54% of all syncopes) were directly discharged, and 443 cases (1.14% of all presentations, 34% of all syncopes) were hospitalized. The remaining 149 cases (12% of all syncopes) refused admission. Following admission, 500 patients were discharged with the diagnosis of syncope: 115 lone-related (23%) and 385 disease-related syncopes (77%). A cost-benefit analysis of the hospitalized patients showed that admitting patients with lone syncope leads to an economical loss to the hospital.

How do we diagnose syncope?

INTRODUCTION: The Eastbourne Syncope Assessment Study aims to increase diagnostic yield in unexplained syncope while reducing investigational costs. The initial study phase was a retrospective analysis of every presentation to the Eastbourne General Hospital (a busy nontertiary center in the United Kingdom serving a population of 250,000; 24% are older than 65 years) with syncope for the year 1998. METHODS AND RESULTS: A total of 1,334 cases with syncopal codes were identified. Six hundred sixty patients (mean age 64 years) had actually suffered an episode of syncope. Forty percent had recurrent syncope, with a mean of 4.7 previous episodes. Twenty-nine percent of syncope cases remained undiagnosed. Forty-four percent were diagnosed as vasovagal, 12% neurologic, 6% due to an arrhythmia, 2% drug related, and 2% due to hemorrhage. Thirteen different types of investigation were undertaken, with an overall total of 3,264 investigations performed at a cost of Pound Sterling 104,285. Diagnosis was achieved by history and examination alone in 61% of cases. Excluding history and examination, the most cost-effective diagnostic tools were the 7-day patient-activated recorder (R test) and tilt testing (Pound Sterling 260 and Pound Sterling 401 per diagnosis, respectively). Investigations also were graded by their relative diagnostic power. Hospital admission alone accounted for 67% of the cost of investigating syncope. CONCLUSION: In syncope, diagnostic rates can be improved and investigational costs reduced by concentrating on the most specific, sensitive, and cost-effective investigations and by minimizing hospital stay. Such a protocol currently is under investigation at our institution.

Vasovagal syncope: prevalence and presentation. An algorithm of management in the aviation environment.

Vasovagal syncope can occur in any individual, given sufficient provocation, and probably half the population suffers at least one episode during life. Often it occurs in youth and may occur in clusters. Usually there is a history of a previous episode. Prodromal symptoms include nausea sweatiness and a sensation of warmth. Diagnosis is by careful history and tilt testing. The false positive rate for passive tilt is 13% and the true positive rate is about 70% including use of nitroglycerine. A classical history and a positive tilt test obviate the need for further investigation in clinical practice, but in the context of aviation, it is wise to seek the small possibility of intermittent rhythm and/or conduction disturbance as an alternative explanation for the episode. It is, therefore, reasonable to carry out a Holter recording and exercise electrocardiogram, perhaps also echocardiography. No treatment is of much benefit, although many agents, including beta blocking drugs, have been used. Some patients have undergone permanent dual chamber pacing with some favourable results. Explanation and reassurance is important. From the licensing point of view, following investigation after an attack, consideration may be given to restricted certification with regular follow-up. Review with investigation after an event free interval, arbitrarily after 2 years, may permit full certification. Malignant vasovagal syncope with no warning of impending attack should disbar.