CARDIOVASCULAR EMERGENCIES (Pulseless Electrical Activity, Bradycardia, Asystole, Air Embolism)
Cardiovascular emergencies include pulseless electrical activity, bradycardia, asystole and air embolism.
Pulseless Electrical Activity
- Assess the patient and conduct a primary ABCD survey
- Review for the most frequent causes of pulseless electrical activity, the five Hs and five and hypothermia and tablets (drug overdose, accidents), tamponade (cardiac), tension pneumothorax, thrombosis (coronary), and thrombosis (pulmonary embolism)
- Administer epinephrine (1 mg IV push repeated every 3 to 5 minutes) or atropine (1 mg IV if the heart rate is slow, repeated every 3 to 5 minutes as needed, to a total dose of 0.04 mg/kg).
- Conduct a secondary ABCD survey
BRADYCARDIA
- Determine whether the bradycardia is slow (heart rate less than 60 beats/min or relatively slow
- Conduct a primary ABCD survey
- Check for serious signs or symptoms caused by the bradycardia
- If no serious signs or symptoms are present, evaluate for a type II second-degree atrioventricular block or third-degree atrioventricularblock
- If neither of these types of heart block is present, observe
- If one of these types of heart block is present, prepare for transvenous pacing, if symptoms develop, use a transcutaneous pacemaker until the transvenous pacer is placed
- If serious signs or symptoms are present, begin the following intervention sequence:
Atropine, 0.5 up to a total of 3 mg IV
Transcutaneous pacing, if available
Dopamine, 5 to 20 mcg/kg/min
Epinephrine, 2 to 10 mcg/min
Isoproterenol, 2 to 10 mcg/min
Conduct a secondary ABCD survey
ASYSTOLE
- Conduct a primary ABCD survey
- Perform transcutaneous pacing immediately if needed. Consider transvenous pacing if transcutaneous pacing fails to capture
- Administer epinephrine ( 1 mg IV push, repeated every 3 to 5 minutes) or atropine (1 mg IV repeated every 3 to 5 minutes, up to a total of 3 mg)
- Conduct a secondary ABCD survey
- If asystole persists, consider withholding or ceasing resuscitative efforts
HYPERTENSIVE EMERGENCY
A hypertensive emergency is an acute, severe elevation in blood pressure accompanied by end-organ compromise. In newly hypertensive patients, a hypertensive emergency is usually associated with a diastolic blood pressure higher than 120 mm/Hg
Etiology
- Essential hypertension
- Renal causes
- Renal artery stenosis
- Glomerulonephritis
- Vascular causes
- Vasculitis
- Hemolytic-uremic syndrome
- Thrombotic thrombocytopenia purpura
- Pregnancy-related causes
- Preeclampsia
- Eclampsia
- Pharmacologic causes
- Sympathomimetics
- Clonidine withdrawal, beta blocker withdrawal
- Cocaine
- Amphetamines
- Endocrine causes
- Cushing’s syndrome
- Pheochromocytoma
- Renin-secreting adenomas
- Thyrotoxicosis
- Neurologic causes
- Central nervous system trauma
- Intracranial mass
- Autoimmune cause
- Scleroderma renal crisis
Signs and Symptoms
Symptoms of end-organ involvement include:
- Headache
- Blurry vision
- Confusion
- Chest pain
- Shortness of breath
- Back pain (e.g., aortic dissection)
- If severe, seizures and altered consciousness
Treatment
- Nitroprusside
- Labetalol
- Fenoldopam
- Enalaprilat
AIR EMBOLISM
An air embolism, or more generally gas embolism, is a pathological condition caused by a gas bubble, or bubbles, in a vascular system.
An air embolism, also called a gas embolism is when an air bubble or air bubbles enter a vein or artery and block it. When the embolism enters a vein, it is called a venous air embolism. When the air enters an artery, it is called an arterial air embolism.
These air bubbles can travel to brain, heart, or lungs and cause a heart attack, stroke, or respiratory failure.
Etiology
- An air embolism can occur when veins or arteries are exposed and pressure allows air to travel into them. This can happen in several ways, such as:
Injections and surgical procedures
- A syringe or IV can accidentally inject air into veins. Air can also enter veins or arteries through a catheter that is inserted into them
- Air can enter veins and arteries during surgical procedures. This is most common during brain surgeries (lung trauma and scuba diving)
This is possible if a person hold his breath, for too long when under water. These actions can cause the air sacs in lungs, called alveoli, to rupture. When the alveoli rupture, air may move to arteries, resulting in an air embolism. (Explosion and blast injuries) (Air into the vagina)
In this case, the air embolism can occur if there is a tear or injury in the vagina or uterus. The risk is higher in pregnant women, who may have a tear in their placenta.
Signs and Symptoms
- Loss of consciousness
- Cessation of breathing
- Vertigo
- Convulsions
- Tremors
- Loss of coordination
- Loss of control of bodily functions
- Numbness
- Paralysis
- Extreme fatigue
- Weakness in the extremities
- Areas of abnormal sensation
- Visual abnormalities
- Hearing abnormalities
- Personality changes
- Cognitive impairment
- Nausea or vomiting
- Bloody sputum
Diagnostic Evaluation
- Ultrasound
- CT scan
- X- ray
Treatment
- A large bubble of air in the heart (as can follow certain traumas in which air freely gains access to large veins) will present with a constant “machinery” murmur.
- It is important to promptly place the patient in Trendelenburg Position
- The Trendelenburg position keeps a left-ventricular air bubble away from the coronary artery ostia so that air bubbles do not enter and occlude the coronary arteries.
- Left lateral decubitus positioning helps to trap air in the nondependent segment of the right ventricle (where it is more likely to remain instead of progressing into the pulmonary artery and occluding it).
- Administration of high percentage oxygen is recommended for both venous and arterial air embolism. This is intended to counteract ischemia and accelerate bubble size reduction
- For venous air embolism the trendelenburg or left lateral positioning of a patient with an air-lock obstruction of the right ventricle may move the air bubble in the ventricle and allow blood flow under the bubble.
- Hyperbaric therapy with 100% oxygen is recommended for patients presenting clinical features of arterial air embolism, as it accelerates removal of nitrogen from the bubbles by solution and improves tissue oxygenation. This is recommended particularly for cases of cardiopulmonary or neurological involvement. Early treatment has greatest benefits, but it can be effective as late as 30 hours after the injury.
