The body’s sudden shutdown: Vasovagal syncope

Felix1*, Muthulakshmi. P2, Pradeep Paul3, Shahila4

1Cath lab nurse Incharge, Kauvery Hospital, Radial Road, Trichy, Tamil Nadu

2Clinical Instructor, Kauvery Hospital, Radial Road, Trichy, Tamil Nadu

3Nurse Educator, Kauvery Hospital, Radial Road, Trichy, Tamil Nadu

4Senior-Critical care unit, Kauvery Hospital, Radial Road, Trichy, Tamil Nadu

*Correspondence

Introduction

Syncope a rapid onset, transient loss of consciousness with spontaneous complete recovery, and resulting from cerebral hypoperfusion – is common. With a cumulative lifetime incidence of 35–50%, syncope accounts for 1–3% of emergency department visits. Vasovagal syncope (VVS) is the most common cause of syncope. While VVS is usually associated with a benign prognosis, it is linked with notable morbidity and psychological distress, particularly if there is a delay in diagnosis. Also, its prognosis may not be as benign as has been assumed, as it appears to carry an increased likelihood of cardiovascular disease in later life.

Recurrent VVS is associated with impaired quality of life, and functional impairment similar to other chronic diseases such as back pain and rheumatoid arthritis. Psychosocial impairment, somatisation, anxiety and depression are common.

Types of syncope

Types of syncope Cause/mechanism Common triggers
Reflex (Neutrally mediated) Autonomic reflex ↓ HR & ↓ BP Pain, Fear, emotional stress, prolonged standing
Vasovagal syncope Excess vagal tone Fear of blood, Pain, Anxiety
Situational syncope Vagal stimulation during activity Coughing, Micturition, defecation, swallowing
Carotid sinus syncope Carotid baroreceptor hypersensitivity Tight collar, Shaving, Neck turning
Orthostatic Hypotension Failure of BP regulation on standing Sudden standing, Dehydration, Drugs
Cardiac syncope ↓ Cardiac output Exertion or sudden onset
Arrhythmic syncope Brady/Tachyarrhythmias Sudden, Unpredictable
Cerebrovascular syncope ↓ Cerebral blood flow Head/neck movement
Syncope Mimics Non-Cardiac causes Variable

Vasovagal syncope

Vasovagal syncope is common, and while it is usually associated with a benign prognosis, it results in significant physical and psychological morbidity for affected individuals. Despite comprehensive understanding of the underlying pathophysiology, there have been few definitive therapeutic advances until recent randomized, controlled trials in pharmacotherapy, pacing and cardioneuro ablation. In this review, we highlight the increasing recognition that the condition is multifactorial, and emphasize and discuss multifaceted management approaches, including education, psychological wellbeing, dietary and fluid intake, pharmacotherapy and cardiac intervention.

Pathophysiology of vasovagal syncope

Pathophysiology of vasovagal syncope When a healthy person stands up, gravitational forces cause 500–1000 mL of blood to pool in the pelvic, abdominal and leg vessels, resulting in reduced venous return to the heart. Baroreceptor firing in the carotid sinus increases dynamically in response to reduced stretch of the vessel wall caused by a fall in arterial pressure. This results in increased sympathetic tone and withdrawal of parasympathetic (vagal) tone, which is mediated by the nucleus solitarius in the brainstem. As a result, the heart rate increases, and peripheral vasoconstriction occurs. Blood pressure (BP) recovers, or is maintained, allowing the individual to continue standing. VVS is a neural reflex involving the autonomic nervous system. This is manifested by the vagally mediated Bezold–Jarisch reflex. In response to reduced filling of the left ventricle or the right atrium by reduced venous return (due to venous pooling in the splanchnic bed), parasympathetic activity is increased and sympathetic activation is decreased. A triad of bradycardia, hypotension and altered respiratory pattern ensure.

Pathophysiology of vasovagal syncope step by step

Evaluation

When assessing an individual with suspected VVS, a comprehensive history and witness account are crucial for making a diagnosis. A detailed description of the circumstances around the event should be elicited, including the ambient environment, temperature, provoking factors, posture at the time of syncope (and the duration of that posture) and the individual’s general health and hydration status at the time. Autonomic symptoms prior to syncope, such as sensations of warmth, nausea, light-headedness, visual dimming and auditory dimming, are very common. Previous episodes, along with medical history and medication history should be recorded. Care should be taken to consider a differential diagnosis, asking specifically about lateral tongue bite, prolonged loss of consciousness and prolonged confusion after the episode, which suggest a seizure. Full details are reported together with the potential for a definite diagnosis by this approach in >90% of those presenting. Absent or very brief prodrome, or injury suggesting lack of warning, should prompt exclusion of arrhythmia or structural heart disease. However, brief or absent prodromes occur in older subjects with VVS mostly due to retrograde amnesia. Detailed physical examination and electrocardiogram should be performed to exclude – as far as possible – structural heart disease, although echocardiography may be needed in some.

Tilt table tests are valuable for confirming the diagnosis. In common with most medical tests, sensitivity and specificity are not perfect, so a negative tilt table test does not exclude VVS.

  • Confirming a diagnosis of reflex syncope (as well as other orthostatic intolerance syndromes) when suspected, but not confirmed;
  • Educating and empowering the patient to recognize symptoms and appreciate the effects of counter pressure manoeuvres; and to recognize a ‘hypotensive susceptibility’ in individuals with unexplained syncope, albeit acknowledging that this may not explain the full mechanism of syncope and thus not make a full diagnosis. Recognition of ‘hypotensive susceptibility’ is of great value when pacing is being considered as, if it exists, future syncope recurrences will be more frequent

Nursing management of vasovagal syncope

Vasovagal syncope is a common type of reflex syncope resulting from increased vagal tone, leading to sudden bradycardia and hypotension, which cause transient reduction in cerebral blood flow and temporary loss of consciousness. Nursing management aims at immediate recovery, prevention of complications, and patient education.

Assessment

  • Assess prodromal symptoms: Dizziness, Nausea, sweating, blurred vision, palpitations.
  • Monitor vital signs ( BP,Pulse,Spo2)
  • Assess level of consciousness
  • Identify triggering factors ( Pain, emotional stress, Prolonged standing, Dehydration)
  • Obtain history of previous episode.

Immediate management during syncope

If patient feels faint:

  • Assist patient to lie down in supine position
  • Elevate legs (Trendelenburg position)
  • Loosen tight clothing
  • Ensure adequate Ventilation

If patient loses consciousness:

  • Maintain airway patency
  • Check breathing and pulse
  • Administer oxygen if needed
  • Monitor vitas signs continuously
  • Do not leave patient alone

Monitoring

  • Continuous cardiac monitoring
  • Monitor BP regularly
  • Record ECG if prescribed
  • Observe for recurrent symptoms

Fluid management

  • Rush the fluid if LV adequate ( if BP low)
  • Encourage adequate oral fluids
  • Promote increase salt intake ( if not contraindicated )

Preventive measure

  • Advise patent to avoid triggers
  • Teach slow position changes ( Avoid sudden standing )
  • Encourage leg crossing and muscle tensing techniques during prodromal symptoms
  • Educate about adequate rest and hydration.
  • In cath lab or post angiogram patient, local anaesthesia may be given before arterial/ venous sheath removal to reduce pain and discomfort, especially for femoral access.

Health education

  • Explain nature of condition ( benign and self-limiting)
  • Teach regarding of warning signs
  • Advise sitting/ Lying down immediately when symptoms start
  • Instruct family on first and management
  • Stress management (Yoga)

Documentation

  • Record time and duration of episode
  • Document vital signs
  • Note precipitating factors
  • Record nursing interventions and patient response

Post episode care

  • Rest until fully alert
  • Slow position changes
  • Document the episode, intervention, and patient response
  • Report recurrent episodes or atypical findings(chest pain, prolonged LOC, seizure activity)

Conclusion

Vasovagal syncope, including episodes that may occur post-procedure, can significantly affect patient safety and comfort. Nursing care plays a critical role in early recognition, monitoring, patient education, and implementing preventive strategies to minimize episodes and ensure optimal recovery and well-being.

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