Cardiovascular Events

Definition

Acute coronary syndrome (ACS) is an acute imbalance between myocardial O ₂ supply and demand that leads to ischemia and infarction. ACS is classified as being unstable angina, non–ST segment elevation myocardial infarction (NSTEMI), or STEMI.

Etiology

Total or subtotal coronary artery occlusion

• Primary ACS results from coronary artery occlusion

  • Plaque disruption with thrombus formation

  • Coronary vasospasm from endothelial dysfunction or drug ingestion (e.g., cocaine, serotonin receptor agonists)

  • Coronary artery embolism

  • Coronary artery dissection

  • Aortic dissection

• Secondary ACS results from

  • Increased myocardial O ₂ demand

  • Decreased myocardial O ₂ supply

Typical Situations

Patients with known CAD or risk factors for atherosclerosis (males, hypertension, hyperlipidemia, diabetes, peripheral vascular disease, smoking, family history of CAD)

• Increased myocardial O ₂ demand

  • Tachycardia, fever, severe hypertension, or thyrotoxicosis

• Decreased myocardial O ₂ supply

  • Systemic hypotension, hypoxemia, or anemia

• Miscellaneous factors (e.g., polyarteritis nodosa, Kawasaki disease)

Prevention

• Evaluate myocardial function and reserve and optimize medical therapy prior to surgery

  • Modify cardiac risk factors if possible

  • Optimize β-blocker and statin therapy

  • Manage antiplatelet therapy (e.g., aspirin, clopidogrel) in collaboration with surgical team

    • Patients with coronary stents on antiplatelet therapy require comanagement with cardiologist and surgeon

      • Patients may require “bridging therapy” (e.g., eptifibatide and heparin) to reduce risk of perioperative stent thrombosis

• Avoid elective anesthesia and surgery in patients with unstable angina or with a history of MI in the previous 6 months

• Optimize hemodynamics and hematocrit during anesthesia

  • Maintain myocardial O ₂ supply

  • Prevent increases in myocardial O ₂ demand

• Revascularization (CABG or PCI) prior to elective surgery is not usually recommended

  • Consult cardiology and cardiac surgery

Manifestations

• In awake patients

  • Chest pain, pressure, or discomfort radiating to arm and jaw

    • Women, diabetics, and the elderly may exhibit atypical chest pain (e.g., epigastric pain, sharp pain, fatigue, or dyspnea) or no symptoms at all

  • Nausea, diaphoresis, palpitations, syncope

  • Cardiac arrest

• Electrocardiogram

  • ST segment elevation or depression

  • Conduction abnormalities (e.g., left bundle branch block or complete atrioventricular block)

  • Peaked T-waves

  • Progression to inverted T-waves and development of Q-waves

  • Arrhythmias including PVCs, VT, or VF

• Cardiac biomarkers

  • Increase in troponin I, troponin T, and CK-MB isoenzyme

  • Diagnosis of MI requires presence of ECG changes or symptoms, because other conditions may be responsible for elevated cardiac biomarkers

• Hemodynamic abnormalities

  • Hypotension

  • Tachycardia

  • Bradycardia

  • New regional wall motion abnormality on TEE or TTE

  • Elevation of filling pressures (CVP, PCWP)

• Criteria required for diagnosis of MI

  • Symptoms of ischemia

  • ECG changes

    • ST segment changes

    • Q-waves

    • New left bundle branch block

  • Evidence of new regional wall motion abnormality

  • Detection of rise and/or fall of cardiac biomarkers including

    • Troponin I

    • Troponin T

    • CK-MB

Similar Events

• PE (see Event 21, Pulmonary Embolism )

• Esophageal spasm, costochondritis, acute abdomen

• Primary pulmonary pathology (e.g., pneumonia, pulmonary infarction)

• Acute aortic dissection

• Nonischemic ST segment or T-wave changes (see Event 12, ST Segment Change )

• ECG artifact

  • Improper electrode placement

  • Changes in patient position or surgical manipulation may alter position of heart relative to the electrodes

Management

• Inform the surgeon

• Confirm diagnosis by evaluating available leads on ECG monitor

• Ensure adequate oxygenation and ventilation

• Optimize hemodynamics—improve myocardial O ₂ supply while decreasing demand

  • Treat hypotension with vasopressors and IV fluids to increase DBP

    • Phenylephrine IV bolus, 50 to 200 μg

    • Phenylephrine IV infusion, 10 to 100 μg/min

    • Optimize circulating blood volume

  • Treat tachycardia

    • Assure adequate depth of anesthesia

    • Administer β-blockers in the absence of evidence of heart failure

      • Esmolol IV, 10 to 30 mg

      • Esmolol IV infusion, 25 to 200 μg/kg/min

      • Metoprolol IV, 1 to 5 mg

    • Calcium channel blockers

      • Diltiazem IV, 0.15 to 0.25 mg/kg load, then 5 to 15 mg/hr

• Improve collateral myocardial blood flow and decrease myocardial wall stress

  • Administer nitroglycerin IV, 0.2 to 2 μg/kg/min

    • Do not administer when patients are hypotensive or have recently taken phosphodiesterase inhibitors

• Draw labs

  • ABG, HCT, electrolytes, cardiac biomarkers

• Consider additional monitoring

  • Arterial line, CVP line, TEE

• Administer aspirin (PO, NGT, or PR) 325 mg

• Treat arrhythmias according to ACLS protocol (see Event 19, Nonlethal Ventricular Arrhythmias )

• In case of STEMI

  • Obtain stat interventional cardiology consult and alert cardiac catheterization laboratory of your concerns for management

  • Terminate surgery as soon as possible and prepare patient for transport to cardiac catheterization lab

  • Evaluate and treat cardiogenic shock

    • Consider treating with vasopressors and/or ionotropes to improve end-organ perfusion

      • Dopamine IV infusion, 2 to 10 μg/kg/min

      • Norepinephrine IV infusion, 10 to 100 ng/kg/min

    • Consider mechanical support with IABP or percutaneous left ventricular assist device (LVAD) for patients not responding to pharmacologic support

  • Consider antiplatelet therapy and anticoagulant therapy

    • Weigh risk of bleeding from recent surgery against benefit of improved mortality from ACS; requires joint discussion with cardiologist and surgeon

• Request ICU bed for postoperative care

Definition

Anaphylactic and anaphylactoid reactions are serious allergic reactions that are rapid in onset and may cause death.

• • Anaphylactic reaction (immunologic) involves antigen and IgE antibodies; requires previous sensitization to the antigen

  • Anaphylactoid reaction (nonimmunologic) mediated primarily by histamine; may occur with the first exposure to a triggering agent

  • Complement activation may follow both immunologic and nonimmunologic reactions

Etiology

Administration or exposure to an agent that the patient has been sensitized to by prior exposure, with production of antigen-specific IgE (anaphylactic reaction)

Allergic reaction to agent requiring no previous exposure (anaphylactoid reaction)

Typical Situations

The true incidence is unknown, but is estimated at 1 in 10,000 to 1 in 20,000 anesthetic procedures. Approximately 1500 deaths occur each year in the United States from anaphylaxis in all settings.

• In patients with a known allergy or sensitivity to a specific agent or with conditions making a reaction to an agent more likely

  • Allergic reactions to protamine are more likely in patients with fish allergy, prior protamine administration, or after treatment with protamine-zinc insulin

  • Patients with a history of allergy to nondrug allergens have a higher risk of anaphylaxis during anesthesia

• After exposure to substances that can trigger anaphylactic or anaphylactoid reactions

  • Neuromuscular blocking drugs (60% of anesthesia-related anaphylaxis)

  • Latex (20% of anesthesia-related anaphylaxis)

  • Antibiotics (15% of anesthesia-related anaphylaxis, with penicillins and cephalosporins responsible for 70% of antibiotic induced anaphylaxis)

  • Opioids

  • Amino-ester local anesthetic agents

  • Blood and blood products

  • Iodinated contrast material

  • Chlorhexidine preparation solutions

  • Individuals with frequent latex exposure

    • Health care workers

    • Patients who have undergone multiple surgical procedures

    • Patients who require intermittent bladder catheterization

      • SCI patients

      • Chronic care patients

Prevention

• Avoid agents to which the patient has a documented allergy

• Minimize the use of latex products in health care (in the United States many institutions have replaced most products with latex-free versions)

• If there is a history of latex allergy, establish a latex-free environment

  • Avoid contact with or manipulation of latex devices

  • Use nonlatex surgical gloves

  • Use syringe/stopcock or unidirectional valves for injecting medications

  • Do not insert a needle through any multiple-dose vial with a natural rubber stopper

    • Take the top of the vial completely off

    • Use medication from a glass ampule, if available

  • Use glass syringes with glass plunger or plastic syringes with known non-latex plungers. (Check manufacturer for materials used.)

• Obtain a careful history of previous allergic reactions, atopy, asthma, or significant latex exposure

• Avoid transfusion of blood or blood products whenever possible

  • Check the identity of the patient and blood products carefully prior to transfusion

• If a specific drug must be administered to a patient known to be at risk of an allergic reaction, administer prophylaxis

  • Corticosteroids

    • Dexamethasone IV, 20 mg, or methylprednisolone IV, 100 mg

  • H ₁ antagonist

    • Diphenhydramine IV, 25 to 50 mg

  • Administer a test dose of drug

• Obtain a consultation from an allergist if a critical allergy must be defined

Manifestations

Anaphylaxis has the potential for acute onset with catastrophic consequences. Severe hypotension, increased PIP, and hypoxemia are the most common initial signs but need not be present simultaneously.

• Cardiovascular

  • The awake patient may complain of dizziness or lose consciousness

  • Severe hypotension

  • Bradycardia—may be initial sign

  • Arrhythmias

  • Cardiac arrest

• Respiratory

  • The awake patient may complain of dyspnea or chest tightness

  • Hypoxemia

  • Decreased lung compliance

  • Severe bronchospasm

• Cutaneous—may be obscured by surgical drapes

  • Flushing, hives, urticaria, pruritus

• Swelling of mucosal membranes, conjunctiva, lips, tongue, and uvula

Similar Events

• Anesthetic overdose (see Event 72, Volatile Anesthetic Overdose )

• Pulmonary edema (see Event 20, Pulmonary Edema )

• Hypotension from other causes (see Event 9, Hypotension )

• ACS (see Event 15, Acute Coronary Syndrome )

• Cardiac tamponade (see Event 18, Cardiac Tamponade )

• Venous air embolism (see Event 24, Venous Air or Gas Embolism )

• Vasovagal reaction

• Septic shock (see Event 13, The Septic Patient )

• Drug administration error (see Event 63, Drug Administration Error )

• Stridor (see Event 36, Postoperative Stridor )

• PE (see Event 21, Pulmonary Embolism )

• Aspiration of gastric contents (see Event 28, Aspiration of Gastric Contents )

• Pneumothorax (see Event 35, Pneumothorax )

• Bronchospasm (see Event 29, Bronchospasm )

• Skin manifestations of drug reactions not associated with anaphylaxis

• Transfusion reaction (see Event 50, Transfusion Reaction )

• Fat embolism syndrome

• Amniotic fluid embolism (see Event 81, Amniotic Fluid Embolism )

Management

• Stop administration of any possible antigen

  • Retain blood products for analysis

  • Remove all latex-containing products from contact with the patient

• Inform the surgeons and call for help

  • Check to see whether they have injected or instilled a substance into a body cavity

  • Consider aborting the surgical procedure if severe

    • Anaphylaxis may be biphasic and can recur after successful initial treatment

• Ensure adequate oxygenation and ventilation

  • Administer 100% O ₂

  • Intubate the trachea if not already intubated

    • The airway can rapidly become very edematous making intubation (or extubation) more difficult or impossible

• Treat hypotension

  • Epinephrine is the drug of choice for treatment of anaphylaxis

    • For mild to moderate hypotension, administer epinephrine IV, 10 to 50 μg increments, and repeat as necessary with escalating doses

    • For cardiovascular collapse or cardiac arrest, administer epinephrine IV, 500 to 1000 μg boluses, and repeat as necessary (see Event 2, Cardiac Arrest )

  • Administer vasopressin IV, 10 to 40 U, in cases of anaphylactic shock resistant to catecholamines; in pulseless arrest, follow the ACLS pulseless arrest algorithm

  • Norepinephrine infusion may be required

  • Glucagon IV, 1 to 5 mg, may be useful in patients receiving β-blocker therapy who do not respond to epinephrine

  • Methylene blue IV, 10 to 50 mg, has been successfully used in catecholamine- and vasopressin-resistant anaphylaxis

• Rapidly expand the circulating fluid volume

  • Place patient in Trendelenburg position

  • Immediate fluid needs may be massive (several liters of crystalloid)

  • Ensure adequate IV access

• Decrease or stop administration of anesthetic agents if hypotension is severe

• If bronchospasm is present

  • Administer bronchodilator

    • Albuterol metered dose inhaler (MDI), 5 to 10 puffs

  • Volatile anesthetics may be administered for bronchodilation if the patient is normotensive

• Administer an H ₁ and H ₂ histamine antagonist

  • Diphenhydramine IV, 50 mg

  • Ranitidine IV, 50 mg

• Administer corticosteroids

  • This is not helpful for the acute event, but may reduce risk of further episodes

  • Dexamethasone IV, 20 mg bolus, or methylprednisolone IV, 100 mg bolus

• In the absence of any other cause, consider latex allergy

  • Ensure all latex products in contact with the patient have been removed from the surgical field (double check whether these products do or do not contain latex)

    • Surgical gloves

    • Urinary catheter

    • Medications drawn up through a latex stopper

  • Place invasive monitors to help guide fluid and vasopressor management

    • Arterial line

    • CVP or PA catheter

    • TTE or TEE

    • Urinary catheter

  • Obtain blood sample for measurement of mast cell tryptase within 2 hours of onset to confirm diagnosis of anaphylactic reaction

  • Arrange admission to an ICU for postoperative management and observation

  • Consider referring patient to an allergist on discharge from the hospital

Complications

• Inability to intubate, ventilate, or oxygenate

• Hypertension, tachycardia from vasopressors

• ARDS

• Renal failure

• Cardiac arrest

• Anoxic brain injury

• Death

Definition

Autonomic dysreflexia (AD) is a massive, unopposed, reflex sympathetic discharge triggered by a noxious stimulus below the level of a chronic SCI.

Etiology

• Bladder or urinary tract distention (e.g., instrumentation, infection, or calculi of the urinary tract)

• Lower GI tract stimulation (e.g., bowel distention from any cause)

• Performance of a surgical procedure below the level of an SCI with inadequate anesthesia/analgesia

• Skin stimulation (e.g., pressure sore, ingrown toenail, tight-fitting clothing)

• Exposure to temperature extremes

• Medications (e.g., nasal decongestants, sympathomimetic drugs, misoprostol)

Typical Situations

• In patients with SCI, usually at least 6 weeks after the injury

• In patients whose level of SCI is at or above T6 (the higher and more complete the lesion, the higher the incidence)

• During performance of urologic procedures such as bladder catheterization, cystoscopy, or cystometrography

• In patients with disorders of the lower GI tract (e.g., fecal impaction, hemorrhoids, anal fissure)

• During procedures involving the rectum or colon

• During recovery from neuraxial, regional, or general anesthesia

• During labor and delivery

Prevention

• Obtain a thorough history from patients with SCI. They are often aware of some of the stimuli that will evoke this response

• Avoid stimuli known to trigger AD if possible

• Check the baseline BP for comparison with perioperative values

• Consider preoperative prophylaxis of patients at risk of AD

  • Clonidine 0.2 to 0.4 mg PO, preoperatively

  • Nifedipine 10 mg SL, immediately preoperatively

  • Phenoxybenzamine 10 mg PO, 3 times daily to maximum of 60 mg/day

  • Prazosin 6 to 15 mg PO

• Provide adequate regional or general anesthesia and postoperative analgesia for a surgical procedure

Manifestations

• Acute, paroxysmal onset of severe systolic and diastolic hypertension

  • Normal BP in most SCI patients is low, so reference the change in BP to the patient’s resting value

  • Increased blood loss from surgical site

  • Reflex bradycardia (tachycardia and arrhythmias may also occur)

• Additional signs of sympathetic hyperreactivity

  • Below the level of SCI: cool, pale skin; pilomotor erection; spastic muscle contraction and increased muscle tone; penile erection

  • Above level of SCI: sweating, vasodilation and flushing of the skin, mydriasis, nasal and conjunctival congestion, eyelid retraction

• If the patient is awake

  • Severe pounding headache, blurred vision, nasal congestion, dyspnea, nausea, or anxiety

Similar Events

• Light anesthesia

• Vasopressor overdose

• Preeclampsia/eclampsia in pregnant SCI patient (see Event 88, Preeclampsia and Eclampsia )

• Intraoperative hypertension from other causes (see Event 8, Hypertension )

• Pheochromocytoma

• Migraine and cluster headaches

Management

Verify the BP; check for additional signs and symptoms of sympathetic hyperreactivity

Inform the surgeon and ask for the surgical stimulus to be stopped (e.g., drain bladder)

Place patient in reverse Trendelenburg position to facilitate venous pooling in lower extremities

• If the patient is under general anesthesia

• • Increase the depth of anesthesia

    • Increase the inspired concentration of volatile anesthetic

    • Administer additional opioid (e.g, fentanyl IV, 25 to 50 μg)

  • If hypertension persists, administer drugs with rapid onset and short duration

    • Phentolamine 2 to 10 mg IV, titrated to effect

    • Sodium nitroprusside IV infusion, 0.2 to 1.0 μg/kg/min, titrated to effect with arterial line monitoring

  • AD may occur during emergence and recovery

• If the patient is awake

• • For less severe hypertension:

    • NTG 0.4 mg/spray into oral cavity

    • Nitropaste 2%, 1 inch applied to the skin above the level of the SCI

    • Captopril 25 mg SL

    • Nifedipine 10 mg capsule, bitten and swallowed

  • For severe elevation in BP:

    • Phentolamine 2 to 10 mg IV, titrated to effect

    • Sodium nitroprusside IV infusion, 0.2 to 2.0 μg/kg/min, titrated to effect with arterial line monitoring

  • If AD resolves, continue with surgery (AD may recur)

• If AD does not resolve with treatment

• Abort surgery if possible

• Place an additional peripheral IV or a CVP line to administer potent vasodilators

• Insert an arterial line if not already done

Complications

• Myocardial ischemia or infarction

• Pulmonary edema

• Hypertensive encephalopathy or stroke

• Atrial and ventricular arrhythmias, heart block

• Seizures, coma, intracerebral or subarachnoid hemorrhage

• Increased surgical blood loss

• Hypotension secondary to therapy with vasodilators

• Cardiac arrest

Definition

Cardiac tamponade is the accumulation of blood, a blood clot, or fluid in the pericardial space, limiting ventricular filling and resulting in hemodynamic compromise.

Etiology

• Bleeding after cardiac surgery

• Coagulopathy

• Cardiac perforation

• Rheumatologic or autoimmune diseases

• Pericardial malignancy or tumor metastasis

• Pericardial infection, typically as a complication of sepsis

• Chronic renal failure

• Radiation-induced pericardial effusion

Typical Situations

• Idiopathic

• Iatrogenic

  • Post cardiac surgery

    • Clots may cause tamponade even in the presence of an open pericardium and patent mediastinal drains

  • Erosion of CVP catheter, especially through right atrial wall

  • Invasive cardiac procedure

    • PCI

    • Electrophysiologic procedure

    • Percutaneous valve repair/replacement

• Trauma, including gun shot wounds (may be insidious in onset)

• Malignancy

• End-stage renal disease

• Collagen vascular disease (e.g., systemic lupus erythematosus, scleroderma)

• Post MI (myocardial rupture, consequences of anticoagulant or thrombolytic therapy)

• Bacterial infection (e.g., tuberculosis)

• Aortic dissection

• Radiation therapy to the mediastinum