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LITERATURE REVIEW Frederick W Campbell, MD, Editor SCIENTIFIC ARTICLES Eisenberg MJ, London MJ, L.eung JM, et al: Monitoring for myocardial ischemia during noncar- disc surgery. A technology assessment of transesoph- ageal echocardiography and 12-lead electrocardio- graphy. J Am Med Assoc 268:210-216,1992 This is one of six articles published in this journal issue focusing on the problem of perioperative myocardial ischemia. Two hun- dred and eighty-five men with evidence of coronary artery disease or clinical risk factors for coronary artery disease undergoing vascular and nonvascular noncardiac surgery underwent intraoper- ative monitoring with transesophageal echocardiographic (TEE) monitoring and continuous 12-lead and two-lead ECG monitoring. Intraoperative myocardial ischemia detected by one or more techniques occurred in 39% of patients. When TEE and 12-lead ECG monitoring results were added to a multivariate model that included preoperative clinical data and two-lead ECG results, the incremental predictive value of TEE was small and of 1Zlead ECG nonsignificant. Intraoperative myocardial ischemia (detected by each of the three monitoring techniques) was associated with a two-fold to three-fold increased likelihood for adverse cardiac outcome (cardiac death, myocardial infarction, unstable angina, congestive heart failure and ventricular tachycardia) than without ischemia. ment (group II, n = 25) of reperfusion-induced ventricular fibrilla- tion. Time to onset of cardiac activity upon reperfitsion was similar in the two groups. There were no significant differences in acid-base or blood gas data, aortic cross-clamp time, CPK-MB, or myoglobin levels between the two groups. Patients who developed reperfusion ventricular fibrillation had significantly higher myocar- dial temperature (27.6” v 25.6”C) at the onset of electrical activity, higher levels of serum sodium (126.1 v 123.9 mMol/L), and significantly lower serum potassium levels (3.55 v 3.98 mMol/L) and lower serum potassium-to-calcium ratios (4.29 v 4.94). Goto M, Flynn AE, Doucette JW, et al: Effect of intracoronary nitroglycerin administration on phasic pattern and transmural distribution of flow during coronary artery stenosis. Circulation 852296-2304, 1992 Grant RP, Dolman JF, Harper JA, et al: Patient- controlled lumbar epidural fentanyl compared with patient-controlled intravenous fentanyl for post- thoracotomy pain. Can J Anaesth 39:214-9,1992 Coronary perfusion pressure, phasic pattern of myocardial blood flow (Doppler ultrasound flowmeter), and transmyocardial blood flow distribution (radioactive microspheres) were measured in a canine model during intracoronary administration of nitroglyc- erin. Nitroglycerin decreased poststenotic coronary arterial pres- sure and increased diastolic blood flow velocity, augmented systolic reverse velocity, and increased the subepicardial flow, but failed to increase subendocardial blood flow. Subendocardial-to-subepicar- dial flow ratio decreased from 0.73 to 0.32. Nitroglycerin clearly relieves angina by reducing myocardial oxygen consumption through its venodilating action. The drug’s effects on the coronary circula- tion are still debated and depend on the model studied. The model did not examine the contribution of collateral vessels to subendo- cardial blood flow. Thirty-four patients were studied in a randomized, double-blind, placebo-controlled comparison of intravenousversus lumbar epidu- ral fentanyl for the first 20 hours after thoracotomy. Fentanyl was delivered in a patient-controlled bolus plus infusion protocol. The cumulative fentanyl requirements were significantly lower in the epidural than the intravenous group (mean 1,857 v 2,573 p,g). There were no differences between the groups with respect to measures of analgesia or pulmonary function. There is obviously some pharmacokinetic difference between the two methods of administering fentanyl that permits equal analgesia with lower dosage in the epidural group. The logical conclusion is a direct neuraxial effect of fentanyl. However, in this group of patients, over the period studied, there is no obvious clinical benefit to using the highly lipophilic opioid fentanyl via the lumbar epidural rather than the intravenous route. Perondi R, Saino A, Totio RA, et al: ACE inhibition attenuates sympathetic coronary vasoconstriction in patients with coronary artery disease. Circulation 85:2004-2013,1992 Diving and cold pressor tests were administered to nine patients with angiographic coronary atherosclerosis during control condi- tions and 30 minutes after captopril, 25 mg, orally. Both sympa- thetic stimulating tests increased blood pressure, rate-pressure product, and coronary vascular resistance during control measure- ments. Coronary blood flow (thermodilution method) decreased under control conditions in response to diving and was unchanged after cold pressor tests. Captopril administration did not change blood pressure, heart rate, or rate-pressure product responses to both stimuli; however, increases in coronary vascular resistance were significantly attenuated. Kinoshita K, Mitani A, Tsuruhara Y, et al: Analysis of determinants of ventricular fibrillation induced by reperfusion: Dissociation between electrical instabil- ity and myocardial damage. Ann Thorac Surg 53:999- 1005,1992 Hood MA, Smith WM: Adenosine versus verapamil in the treatment of supraventricular tachycardia: A randomized double-crossover trial. Am Heart J 123: 1543-1549,1992 Sixty-two patients undergoing open heart surgery were divided Of 32 patients with narrow complex tachycardia, 22% experi- into two groups based on absence (group I, n = 37) or develop- enced conversion to sinus rhythm with carotid sinus massage. The Journalof Cardiorhoracic and VascularAnesthesia, Vol7, No 1 (February), 1993:pp 117-l 19 117

Monitoring for myocardial ischemia during noncardiac surgery. A technology assessment of transephageal echocardiography and 12-lead electrocardiography

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Page 1: Monitoring for myocardial ischemia during noncardiac surgery. A technology assessment of transephageal echocardiography and 12-lead electrocardiography

LITERATURE REVIEW Frederick W Campbell, MD, Editor

SCIENTIFIC ARTICLES

Eisenberg MJ, London MJ, L.eung JM, et al: Monitoring for myocardial ischemia during noncar- disc surgery. A technology assessment of transesoph- ageal echocardiography and 12-lead electrocardio- graphy. J Am Med Assoc 268:210-216,1992

This is one of six articles published in this journal issue focusing on the problem of perioperative myocardial ischemia. Two hun- dred and eighty-five men with evidence of coronary artery disease or clinical risk factors for coronary artery disease undergoing vascular and nonvascular noncardiac surgery underwent intraoper- ative monitoring with transesophageal echocardiographic (TEE) monitoring and continuous 12-lead and two-lead ECG monitoring. Intraoperative myocardial ischemia detected by one or more techniques occurred in 39% of patients. When TEE and 12-lead ECG monitoring results were added to a multivariate model that included preoperative clinical data and two-lead ECG results, the incremental predictive value of TEE was small and of 1Zlead ECG nonsignificant. Intraoperative myocardial ischemia (detected by each of the three monitoring techniques) was associated with a two-fold to three-fold increased likelihood for adverse cardiac outcome (cardiac death, myocardial infarction, unstable angina, congestive heart failure and ventricular tachycardia) than without ischemia.

ment (group II, n = 25) of reperfusion-induced ventricular fibrilla- tion. Time to onset of cardiac activity upon reperfitsion was similar in the two groups. There were no significant differences in acid-base or blood gas data, aortic cross-clamp time, CPK-MB, or myoglobin levels between the two groups. Patients who developed reperfusion ventricular fibrillation had significantly higher myocar- dial temperature (27.6” v 25.6”C) at the onset of electrical activity, higher levels of serum sodium (126.1 v 123.9 mMol/L), and significantly lower serum potassium levels (3.55 v 3.98 mMol/L) and lower serum potassium-to-calcium ratios (4.29 v 4.94).

Goto M, Flynn AE, Doucette JW, et al: Effect of intracoronary nitroglycerin administration on phasic pattern and transmural distribution of flow during coronary artery stenosis. Circulation 852296-2304, 1992

Grant RP, Dolman JF, Harper JA, et al: Patient- controlled lumbar epidural fentanyl compared with patient-controlled intravenous fentanyl for post- thoracotomy pain. Can J Anaesth 39:214-9,1992

Coronary perfusion pressure, phasic pattern of myocardial blood flow (Doppler ultrasound flowmeter), and transmyocardial blood flow distribution (radioactive microspheres) were measured in a canine model during intracoronary administration of nitroglyc- erin. Nitroglycerin decreased poststenotic coronary arterial pres- sure and increased diastolic blood flow velocity, augmented systolic reverse velocity, and increased the subepicardial flow, but failed to increase subendocardial blood flow. Subendocardial-to-subepicar- dial flow ratio decreased from 0.73 to 0.32. Nitroglycerin clearly relieves angina by reducing myocardial oxygen consumption through its venodilating action. The drug’s effects on the coronary circula- tion are still debated and depend on the model studied. The model did not examine the contribution of collateral vessels to subendo- cardial blood flow.

Thirty-four patients were studied in a randomized, double-blind, placebo-controlled comparison of intravenousversus lumbar epidu- ral fentanyl for the first 20 hours after thoracotomy. Fentanyl was delivered in a patient-controlled bolus plus infusion protocol. The cumulative fentanyl requirements were significantly lower in the epidural than the intravenous group (mean 1,857 v 2,573 p,g). There were no differences between the groups with respect to measures of analgesia or pulmonary function. There is obviously some pharmacokinetic difference between the two methods of administering fentanyl that permits equal analgesia with lower dosage in the epidural group. The logical conclusion is a direct neuraxial effect of fentanyl. However, in this group of patients, over the period studied, there is no obvious clinical benefit to using the highly lipophilic opioid fentanyl via the lumbar epidural rather than the intravenous route.

Perondi R, Saino A, Totio RA, et al: ACE inhibition attenuates sympathetic coronary vasoconstriction in patients with coronary artery disease. Circulation 85:2004-2013,1992

Diving and cold pressor tests were administered to nine patients with angiographic coronary atherosclerosis during control condi- tions and 30 minutes after captopril, 25 mg, orally. Both sympa- thetic stimulating tests increased blood pressure, rate-pressure product, and coronary vascular resistance during control measure- ments. Coronary blood flow (thermodilution method) decreased under control conditions in response to diving and was unchanged after cold pressor tests. Captopril administration did not change blood pressure, heart rate, or rate-pressure product responses to both stimuli; however, increases in coronary vascular resistance were significantly attenuated.

Kinoshita K, Mitani A, Tsuruhara Y, et al: Analysis of determinants of ventricular fibrillation induced by reperfusion: Dissociation between electrical instabil- ity and myocardial damage. Ann Thorac Surg 53:999- 1005,1992

Hood MA, Smith WM: Adenosine versus verapamil in the treatment of supraventricular tachycardia: A randomized double-crossover trial. Am Heart J 123: 1543-1549,1992

Sixty-two patients undergoing open heart surgery were divided Of 32 patients with narrow complex tachycardia, 22% experi- into two groups based on absence (group I, n = 37) or develop- enced conversion to sinus rhythm with carotid sinus massage. The

Journalof Cardiorhoracic and VascularAnesthesia, Vol7, No 1 (February), 1993: pp 117-l 19 117