Ch 5 Syncope

Chapter Objectives

• By the end of this chapter, you should be able to:

  • Use terms presented in the chapter

  • Discuss the physiology of syncope

  • List signs and symptoms of vasovagal syncope

  • Choose the correct course of management for syncope

Chapter Objectives (continued)

• By the end of this chapter, you should be able to:

  • Discuss the steps required to manage an episode of vasovagal syncope

  • Describe how syncope can be prevented

  • Identify the causes for postural hypotension

  • Discuss the prevention of postural hypotension

Chapter Objectives (continued)

• By the end of this chapter, you should be able to:

  • Explain the steps involved in managing postural hypotension

  • Compare and contrast vasodepressor syncope and postural hypotension

Syncope Overview

• Definition: Loss of consciousness, commonly referred to as 'the common faint'.

• Context: It is the most prevalent life-threatening emergency that may occur in a dental office.

• Pathophysiology: Caused by a decrease in blood flow to the brain, leading to a lack of cerebral oxygenation and resulting in cerebral ischemia (Grimes, 2009).

• Significance: Although common, syncope must be corrected promptly; it should be treated as a cardiac arrest until otherwise diagnosed.

Causes of Syncope

• General Overview: Can be caused by various forms of stress, which can be physical, emotional, or both.

  • Psychogenic Causes: Includes psychological factors such as fear, pain, emotional upset, and anxiety. These are noted as the most common causes of syncope in the dental office.

  • Nonpsychogenic Causes: Physical causes which may include hunger, poor health, and prolonged upright positioning.

Types of Syncope

• Cardiac Syncope: Secondary to arrhythmic or obstructive events.

• Noncardiac Syncope:

  • Seizures

  • Orthostatic Hypotension

  • Situational Occurrences

  • Hyperventilation

  • Metabolic Diseases

  • Neurocardiac/Vasodepressor Syncope

  • Triggered by noxious stimuli and activation of the sympathetic division of the autonomic nervous system (Grimes, 2009).

Physical Changes Resulting in Syncope

• When the body experiences stress:

  • Vascular bed dilates, causing blood to be directed to the extremities (associated with fight-or-flight response).

  • Blood fails to recirculate adequately and pools in the extremities, leading to decreased blood flow and oxygenation to the brain.

  • This leads to unconsciousness.

Signs and Symptoms of Syncope

• Stages of Syncope:

  • Presyncope (First Stage):

  • Symptoms: Patient appears pale, profusely sweating, may report nausea, dizziness, or feeling excessively hot.

  • Vital Signs: Slight decrease in blood pressure and a rapid increase in pulse.

  • Syncope (Second Stage):

  • Symptoms: Patient may exhibit a deathlike appearance, shallow or gasping breaths, potential slight convulsions, and dilated pupils.

  • Vital Signs: Very low blood pressure and a weak, slow pulse.

Management of Syncope

• Initial Steps:

  • Remain calm and stop all dental treatment immediately.

  • Place the patient in the Trendelenburg position (supine position with feet slightly elevated).

  • If in the dental chair, elevate the feet; if in the hallway or waiting room, lay the patient flat and elevate their feet using available assists.

  • Special Considerations for Pregnant Patients:

  • Do not place pregnant patients in Trendelenburg position; instead, position them on their side with elevated feet.

  • Post-Management Protocol:

  • If recovery does not happen, use head tilt/chin lift techniques for airway management.

• Subsequent Actions Post-Positioning:

  • Crack ammonia capsule and wave under patient’s nose briefly (no prolonged exposure).

  • Administer pure oxygen (4-6 L/min) to aid in patient comfort.

  • Loosen patient clothing and place a cold towel on their forehead.

  • If bradycardia continues for more than a few minutes, administer 0.6 mg atropine intramuscularly (IM).

  • Note that prolonged syncope may occur, triggering seizures due to inadequate cerebral oxygenation.

Recovery from a Syncopal Episode

• Patients post-episode may feel confused and upset; important to:

  • Explain the situation calmly and reassuringly.

  • Remove any predisposing stimuli (e.g., needles).

  • Never leave the patient unattended.

  • Document the episode in the patient's chart.

Prevention of Syncope

• If presyncope symptoms are observed, cease dental treatment immediately and place the patient in Trendelenburg position.

  • Further considerations include:

  • Reduce patient anxiety regarding the dental environment (alleviate fears).

  • Create a comfortable atmosphere and mitigate dental office sounds/smells that may induce stress.

  • Some patients might require premedication to alleviate extreme anxieties.

• Health History Updates:

  • Maintaining and updating patient health histories is crucial; those with past syncope history may be predisposed to experiencing syncope during visits.

  • Implement extra precautions where necessary.

Predisposing Factors to Postural Hypotension

• High-Risk Groups:

  • Elderly patients: Varicose veins may contribute.

  • Pregnant women:

  • In first/second trimester: Increases in circulatory system volume with decreasing blood pressure.

  • In third trimester: Lying supine for extended periods can compress the vena cava; turning the patient to the left can reduce this pressure.

• Associated Medical Conditions:

  • Heart conditions (e.g., myocardial infarction, heart valve defects, congestive heart failure) can result in decreased blood pressure due to poor circulation.

  • Medical conditions such as hypoglycemia, hypothyroidism, and adrenal insufficiency may also lead to drops in blood pressure.

  • Certain medications (e.g., blood pressure medications, antipsychotics, sedatives) used in the dental field can alter blood pressure.

• Prolonged Recumbence:

  • Long dental appointments might necessitate gradual adjustments in chair position to ensure patient safety and comfort.

Protocol for Prevention of Postural Hypotension

• Upright Position Protocol:

  • Move the dental chair slowly to an upright position.

  • Transition from supine to semi-supine, allowing the patient to sit for 2-3 minutes before reaching the full upright position.

  • Allow the patient to adjust comfortably while seated for another 2 minutes before standing.

  • Stand near the patient during this transition for safety.

Protocol for Managing an Episode of Postural Hypotension

• Assess the situation while using head tilt/chin lift to ensure an open airway.

• Check for patient breathing. Recovery is expected to be swift in a supine position.

• Follow recovery protocols outlined in Table 4-2 after recovery; if recovery is delayed, consider a serious underlying medical problem and call EMS.

Comparison of Vasovagal Syncope and Postural Hypotension

Shock Overview

• Definition: Shock is characterized by a lack of oxygenated blood to body tissues, inhibiting their metabolic needs. This leads tissues to perform anaerobic metabolic processes, producing toxins and acidosis, which can be harmful to the cardiovascular system (Grimes, 2009).

Stages of Shock

• Initial Stage:

  • Cells become deprived of oxygen and are unable to produce energy.

• Compensatory Stage:

  • Physiological changes occur to combat the effects of shock:

  • Increased respiration to compensate for oxygen deprivation.

  • Increased blood pressure to address hypotension.

  • Reduced blood supply to peripheral areas to direct more blood to the brain.

  • Kidneys are compromised, resulting in decreased urine output (oliguria) (Grimes, 2009).

• Progressive Stage:

  • The body's ability to compensate begins to fail, compromising vital organ function and leading to malfunctions.

• Refractory Stage:

  • Characterized by the failure of vital organs, causing irreversible damage and cell death; brain damage can occur, potentially leading to death within hours (Grimes, 2009).

Types of Shock and Their Management

Hypovolemic Shock

• Signs and Symptoms:

  • Dehydration, rapid and thready pulse, cool skin, decreased urine output, mental confusion.

• Characteristics:

  • Most common shock type; relates to inadequate venous return to the heart due to causes such as hemorrhage or dehydration (Grimes, 2009).

Cardiogenic Shock

• Signs and Symptoms:

  • Cyanosis, fast weak pulse, cold clammy skin, nonspecific chest pain, shortness of breath, decreased urine output, mental confusion, decreased BP (systolic below 90 mmHg).

• Characteristics:

  • Results from decreased tissue perfusion due to decreased cardiac output, often related to myocardial infarction, cardiac arrhythmias, or cardiac dysfunction (Grimes, 2009).

Distributive Shock

• Signs and Symptoms:

  • Anaphylactic Shock: Hypotension, restlessness, anxiety, tachycardia, respiratory arrest.

  • Septic Shock: Fever, increased cardiac output, tissue edema, pink warm skin, thirst, respiratory failure.

• Characteristics:

  • Encompasses vasogenic shock due to vasodilation and abnormal fluid distribution in the circulatory system; includes anaphylactic, septic, and neurogenic shock (Grimes, 2009).

Neurogenic Shock

• Signs and Symptoms:

  • Hypotension, bradycardia, peripheral vasodilation.

• Characteristics:

  • Loss of sympathetic nerve activity from the brain’s vasomotor center leads to peripheral vascular dilation and decreased venous return to the heart, triggered by emotional trauma, disease, drugs, or injuries to the spinal cord or brain stem (Grimes, 2009).

Obstructive Shock

• Signs and Symptoms:

  • Severe hypotension, dyspnea.

• Characteristics:

  • Arises from indirect heart pump failure leading to decreased cardiac function and circulation due to factors such as arterial stenosis, pulmonary embolism, or cardiac tamponade (Grimes, 2009).

Management of Shock

• General Management Recommendations:

  • Remove the source of obstruction as necessary.

  • Surgical intervention may be required based on the obstruction.

  • Administer IV fluids cautiously, performed by trained professionals.

  • Early intervention is key (Grimes, 2009).