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.

Psychosocial and cognitive engineering contributions to blood transfusion.

Among the research developed in social psychology, there is a field of study questioning the mechanisms that explain prosocial behaviors. In 1956, the first links between transfusion medicine and social psychology were formed, with the study of underlying motivations to blood donation behavior. Sixty years later, the number of "fundamental" and "applied" research has widely increased, and we now have a theoretical understanding of blood donation engagement's levers, as well as experimental demonstrations of methods to activate these levers. Thus, the literature offers several strategies experimentally verified to improve the recruitment and retaining of blood donors. These methods can go from specific speeches when soliciting donors, to changes in the blood donation environment, etc. They aim either at impacting the donation experience, at obtaining a change in the donor's behavior, or at changing the determinants of blood donation. Yet, it is clear that the knowledge from the research in social psychology is not really deployed on the field by the organizations that could benefit from it. In this article, we will try to develop the difficulty regarding the application of fundamental and experimental knowledge, and to underline the implications for the blood transfusion establishments. We will then present the psychosocial and cognitive engineering method, and argue its relevance to answer this problematic.

Novel functional advanced echocardiography for the assessment of myocardial mechanics in children with neurocardiogenic syncope - a blinded prospective speckle tracking head-up tilt-table challenge study.

BACKGROUND: Data on left ventricular (LV) function in patients with neurocardiogenic syncope (NS) is conflicting in adults and lacking in children. The aim of this study was to analyze LV myocardial performance in children with NS at rest and during head-up tilt-table (HUTT) testing. METHODS: This is the first study to combine HUTT and speckle-tracking echocardiography (STE) in children with NS. 43 consecutive normotensive pediatric patients with NS (mean age 13.9 ± 2.6 years, 51% female) and 41 sex- and age-matched healthy controls were included in the study. The study groups consisted of 21 patients with a positive HUTT reaction (HUTT+) and 22 with a negative HUTT reaction (HUTT-). STE was used to analyze peak systolic LV myocardial strain and strain rate. RESULTS: Conventional echocardiographic parameters were similar in all analyzed groups. When compared to healthy controls, children with NS had depressed levels of circumferential strain rate (p = 0.032) and significantly depressed longitudinal strain rate (p <  0.001) at rest. Interestingly, during HUTT testing LV global strain and strain rate were similar in both groups. LV strain rate was lowest in HUTT+ followed by HUTT- and control subjects both at rest and during HUTT. CONCLUSIONS: Resting LV longitudinal strain rate is attenuated in children with NS, especially in those with a positive HUTT response. This is further evidence that NS patients feature altered cardiac mechanics rendering them prone to vasovagal perturbations that can ultimately result in collapse. TRIAL REGISTRATION: Witten/Herdecke University ethics committee clinical study number: UWH-73-2014.

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.

Update on the role of pacemaker therapy in vasovagal syncope and carotid sinus syndrome.

Vasovagal syncope (VVS) and carotid sinus syndrome (CSS) are related, neurally mediated disorders with different clinical features and treatment implications. Pacemaker intervention studies in both syndromes are hampered by a dearth of randomized, controlled (particularly with placebo) studies, unfortunate premature termination of studies, and variation in both the clinical presentation and cardiovascular profile of patients enrolled. Given this relatively limited evidence base, pacing therapy in VVS should be reserved for older sufferers with relatively frequent symptoms and spontaneous asystole documented during real-life monitoring. The long term course of patients paced for vasovagal syncope needs clarification, both in terms of symptom and device-related burden, while a comprehensive health economic evaluation of the costs and benefits of such an invasive approach for this usually benign condition is essential. It will also be important to determine the efficacy of closed loop stimulation pacing in an adequately powered study, including a comparison with standard pacing. Pacing should be considered in those with unexplained syncope with reproduction of symptoms during a cardio-inhibitory or mixed response to carotid sinus massage (asystole >3 s), though the evidence base for this recommendation is firmly in the consensus rather than pragmatic randomized controlled trial camp. Patients presenting with unexplained falls and drop attacks, particularly where injuries are prominent and where patients cannot give a clear account of their fall ("I just ended up on the floor, didn't slip or trip"), should also be considered for pacing. Pacing is not recommended for the vasodepressor sub-type of CSS.

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.

What is the optimal duration of tilt testing for the assessment of patients with suspected postural tachycardia syndrome?

AIMS: The aim of this study is to define the optimal duration of tilt testing for the assessment of patients with suspected postural tachycardia syndrome (POTS). METHODS AND RESULTS: This was a case-control study. Cases were identified retrospectively from a database of patients referred with orthostatic intolerance (OI). All met the diagnostic criteria for POTS. Controls were enrolled prospectively. All subjects underwent tilting to 70 degrees for 40 min if tolerated. Continuous monitoring was provided by a Finometer. Analysis of responses to tilting was performed on 28 cases and 28 controls. The mean age in the case group was 23.6 and in the control group was 26.2. The majority was female in both groups (cases = 4F:3M, controls = 2F:1M). All cases met the criteria for POTS within 7 min of orthostasis. No controls demonstrated a sustained tachycardia. The prevalence of vasovagal syncope (VVS) was 36% in cases vs. 7% in controls (P = 0.02) and 25% in the remaining patients (n = 233) on the OI database (P = 0.259). CONCLUSION: A 10 min tilt will diagnose POTS in the majority of patients. It will not, however, be sufficient to identify the overlap that exists between POTS and VVS. The optimal duration of tilt testing in patients suspected of POTS is 40 min.

Pathophysiology and management of neurocardiogenic syncope.

OBJECTIVE: To discuss the physiologic mechanisms underlying neurocardiogenic syncope in the context of several different management strategies. PATHOPHYSIOLOGY: Neurocardiogenic syncope or the "common faint" is variously called neurally mediated hypotension, vasovagal syncope, or vasodepressor syncope. It is the most common type of syncope. The pathophysiology of neurocardiogenic syncope is complex and not completely elucidated. Individuals susceptible to neurocardiogenic syncope are unable to maintain the adaptive neurocardiovascular responses to upright posture for prolonged periods. These patients tend to have a modest reduction in central blood volume, which is aggravated by upright posture. It is often noted in individuals receiving sympathetic blocking agents and vasodilator drugs for hypertension, elderly patients receiving tranquilizers, patients with anemia, and individuals with tran- sient reductions in blood volume such as those that occur after a brisk diuresis or blood donation. The classic syncopal episode often is preceded by a constellation of prodromal symptoms several seconds before the event that may include nausea, headache, diaphoresis, dizziness, chest pain, palpitations, dyspnea, and paresthesia. MANAGEMENT: Head-up tilt testing has become the diagnostic study of choice for the identification of patients with neurocardiogenic syncope. Therapeutic options include general measures such as volume expansion; pharmacologic approaches such as beta-adrenergic receptor blockade, anticholinergic agents, selective serotonin reuptake inhibitors, methylxanthines, and alpha agonists; and invasive methods such as placement of a dual-chamber cardiac pacemaker.

HyCoSy--as good as claimed?

Hysterosalpingo contrast sonography (HyCoSy) has been compared favourably in the literature with hysterosalpingography (HSG). It does not require ionizing radiation and demonstrates the uterus and ovaries. HyCoSy is reported as being a safe, well tolerated, quick and easy investigation of Fallopian tube patency. Over a 1-year period HyCoSy was performed by two operators on 118 consecutive women who were thought likely to have patent Fallopian tubes. The examinations were graded using a local scale to assess discomfort and were correlated with tubal patency. HSG was performed on 116 patients by the same operators and discomfort recorded. 15 patients underwent both examinations. The degree of pain or reaction was graded 0 (no pain) to 4 (maximum) according to a locally devised scale. Costs of the two examinations were estimated. 89 patients examined by HyCoSy were graded 0-2. However, 23 had severe protracted pain and/or vasovagal reactions with bradycardia and hypotension. Of these, seven required resuscitation owing to prolonged symptoms, requiring treatment with atropine. 19 of the 23 had bilaterally patent Fallopian tubes. Where subsequent HSG was performed, tubal occlusion was confirmed in 8 of 15 women. Other pathologies were noted in 29 of the HyCoSy patients and there were six technical failures. During the same period no severe adverse reactions occurred in 116 patients having HSG performed by the same operators. Three of the HSG examinations were technically unsuccessful. Discomfort following HyCoSy was much greater than that reported previously. Possible mechanisms are discussed but it does not appear to be related to tubal occlusion. Diagnostic accuracy, costs and discomfort compare unfavourably with HSG.

Pacing to prevent vasovagal syncope.

Patients with frequent vasovagal syncope have markedly poor quality of life and are often resistant to treatment with standard pharmacologic approaches. Vasovagal syncope is due to combinations of bradycardia and hypotension. There is accumulating evidence that many of these patients may respond to permanent cardiac pacing. Several controlled open-label studies suggest that about half of paced patients no longer faint, and most of the rest are improved. At this point, we do not know the role of placebo, and specific pacing modes in this improvement are not known. Ongoing trials will clarify how to select patients and how best to pace them.