Summary of study session III
In study session III you have learnt
- Myocardial ischemia (coronary artery disease) is characterized by a metabolic oxygen demand that exceeds the oxygen supply. Common causes include severe hypertension or tachycardia (particularly in the presence of ventricular hypertrophy); coronary arterial vasospasm or anatomic obstruction; severe hypotension, hypoxemia, or anemia; and severe aortic stenosis or regurgitation.
- Angina pectoris is typically described as retrosternal chest discomfort, pain, pressure, or heaviness. The chest discomfort often radiates to the neck, left shoulder, left arm, or jaw and occasionally to the back or down both arms.
- Chronic stable angina refers to chest pain or discomfort that does not change appreciably in frequency or severity over 2 months or longer. Unstable angina is defined as an abrupt increase in severity, frequency (more than three episodes per day), angina at res.
- Acute myocardial infarction is serious complication of ischemic heart disease results in sudden death of part of myocardium from ischemia and necrosis of part of the myocardium.
- The general approach in treating patients with ischemic heart disease includes correction of coronary risk factors, modification of the patient's lifestyle to eliminate stress and improve exercise tolerance, correction of complicating medical conditions, administration of pharmacological agents such as nitrates, beta-blockers, and calcium channel blockers.
- Patient with a known heart disease including ischemic heart disease shall be referred to a resourceful hospital that could handle cardiac patients. Preventing ischemic heart disease under anesthesia is a vital importance at any level of hospital.
- Regional anesthesia is often a good choice for procedures involving the extremities, the perineum, and possibly the lower abdomen.
- The patient should be evaluated preoperatively; the severity, progression, and functional limitations imposed by ischemic heart disease and use of current medication, EKG test and laboratory investigation must be done.
- Induction of anesthesia is acceptably accomplished with the intravenous administration of rapidly acting drugs. Etomidate is a popular anesthetic to induce anesthesia, propofol is popular secondary choice but ketamine is relatively contraindicated.
- Adequate anesthesia and a brief duration of direct laryngoscopy is important in minimizing the magnitude of these circulatory changes. Lidocaine (1.5 mg/kg IV), administered just before initiating direct laryngoscopy, is efficacious.
- Patients are generally managed with an opioid-volatile anesthetic technique.
- Continuous ECG monitoring, along with blood pressure measurement, pulse oximetry, and end-tidal carbon dioxide (CO2) analysis are standard monitors for all anesthetized patients.
- Recovery from anesthesia and the immediate postoperative period can continue to stress the myocardium. The patient should receive supplemental oxygen until adequate oxygenation is established.
- Hypothermia and pain should be corrected
- Heart failure is a complex pathophysiologic state described by the inability of the heart to fill with or eject blood at a rate appropriate to meet tissue requirements.
- Patient with congestive heart failure should is subjected only for life saving surgeries and be managed in central hospitals which have many specialty and other resources to optimize patient condition preoperatively, manage anesthesia perioperatively and provide critical care postoperatively.
- When surgery cannot be delayed, however, the drugs and techniques chosen to provide anesthesia must be selected with the goal of minimizing detrimental effects on cardiac output.
- Etomidate or small dose ketamine may be useful for the induction of anesthesia in the presence of congestive heart failure because of its limited effect on the sympathetic nervous system. Small concentrations of volatile anesthetics can maintain anesthesia, but cardiac depression should be avoided if possible.
Last modified: Sunday, 20 November 2016, 1:13 PM