Management Of Anesthesia In Ischemic Hear Disease

Patients(brief practical review)

Reza Aminnejad; M.D.Anesthesiologist.

In The Name of God

Ischemic Heart Disease

Management of anesthesia in patients with known or suspected IHD undergoing

non cardiac surgery

Intraoperative Management (Basic Challenges)

Prevent myocardial ischemia by optimizing myocardial oxygen supply and reducing myocardial oxygen demand

Monitor for ischemia and treat ischemia if it develops.

Intraoperative Events That Influence the Balance Between Myocardial Oxygen Delivery and Myocardial Oxygen Requirements Decreased O2 Delivery (Decreased

coronary blood flow, Tachycardia, Diastolic hypotension, Hypocapnia (coronary artery vasoconstriction), Coronary artery spasm, Decreased oxygen content, Anemia, Arterial hypoxemia, Shift of the oxyhemoglobin dissociation curve to the left)

Increased O2 Requirements (Sympathetic nervous system stimulation, Tachycardia, Hypertension, Increased myocardial contractility, Increased afterload, Increased preload)

Maintenance of the balance between myocardial oxygen supply and demand is more important than the specific anesthetic technique or drugs selected to produce anesthesia and muscle relaxation.

A common recommendation is to keep the heart rate and blood pressure within 20% of the normal awake value.

Induction of Anesthesia Intravenous induction drug is preferred. Short-duration direct laryngoscopy

(≤15 seconds) is considered. Laryngotracheal lidocaine, intravenous

lidocaine, esmolol, and fentanyl have all been shown to be useful for blunting the increase in heart rate evoked by tracheal intubation.

Maintenance of Anesthesia In patients with normal LV function volatile

anesthetic with or without N2O or N2O– opioid technique with the addition of a volatile anesthetic to treat any undesirable increases in BP that accompany painful surgical stimulation is recommended.

In patients with severely impaired LV function opioids may be selected. A benzodiazepine may be needed for amnesia but the addition of N2O or a volatile anesthetic may be associated with myocardial depression.

It seems prudent to maintain intraoperative heart rate at less than 80 bpm.

Choice of Muscle Relaxant Vecuronium, rocuronium &

cisatracurium have minimal or no effect on HR & SBP.

For reversal of neuromuscular blockade with an anticholinesterase / anticholinergic drug combination, glycopyrrolate, which has much less chronotropic effect, is better than Atropine.

Monitoring ECG PCWP TEE

Relationship of Electrocardiogram Leads to Areas of Myocardial Ischemia Leads II, III & aVF→ RCA→ RA, RV,

SA node, Inferior aspect of LV, AV node

Leads I & aVL→ CCA→ Lateral aspect of LV

Leads V3–V5→ LAD→ Anterolateral aspect of LV

Pulmonary Artery Catheter Intraoperative myocardial ischemia can manifest as

an acute increase in pulmonary artery occlusion pressure due to changes in left ventricular compliance and systolic performance.

A pulmonary artery catheter is not a sensitive monitor for detecting small ischemic insults but it can be more useful as a guide in the treatment of myocardial dysfunction.

Use of a pulmonary artery catheter has not been shown to be associated with improved outcomes.

CVP and pulmonary artery occlusion pressure correlate in patients with ischemic heart disease when the ejection fraction is greater than 50% .

TEE (Trans Esophageal Echocardiography)

Regional wall motion abnormalities occur before ECG changes occur.

The limitations of TEE include its cost, the need for extensive training in interpretation, and the fact that it cannot be inserted until after induction of anesthesia.

Intraoperative Management of Myocardial Ischemia

Treatment of myocardial ischemia should be instituted when there are 1-mm ST-segment changes on the ECG.

Prompt, aggressive pharmacologic treatment of changes in heart rate and/or blood pressure is indicated.

Consider esmolol for persistent increas in HR & nitroglycerin for normal or modestly elevated BP.

Hypotension is treated with sympathomimetic drugs to restore coronary perfusion pressure.

In an unstable hemodynamic situation, circulatory support with inotropes or an intra-aortic balloon pump may be necessary.

Postoperative Management Prevent intraoperative hypothermia, pain,

hypoxemia, hypercarbia, sepsis, and hemorrhage.

Continue β-blockers throughout the perioperative period.

Maintain intravascular volume and an adequate hemoglobin concentration.

patients with IHD can become ischemic during emergence from anesthesia and/or weaning with an increased heart rate and blood pressure.