Do changes in pulmonary capillary wedge pressure adequately reflect myocardial ischemia during anesthesia? A correlative preoperative hemodynamic, electrocardiographic, and transesophageal echocardiographic study

Speckle- Tracking Echocardiography for the Staging of Diastolic Dysfunction: The Correlation Between Strain-Based Indices and the Severity of Left Ventricular Diastolic Dysfunction

OBJECTIVES

Left ventricular diastolic function can be assessed by various methods. Tissue Doppler imaging is among the most commonly used techniques. However, this imaging is angle- dependent, affected by loading conditions, and susceptible to myocardial tethering. Speckle- tracking echocardiography also can measure strain-based indices to assess diastolic function, and it has fewer limitations than tissue Doppler imaging. Using speckle- tracking echocardiography, the authors evaluated the correlation between the stage of diastolic dysfunction and strain-based indices in patients undergoing cardiac surgery to determine whether strain-based indices can be used intraoperatively to identify the extent of left ventricular diastolic dysfunction.

DESIGN

Retrospective clinical study.

SETTING

Single university hospital.

PARTICIPANTS

Fifty-eight patients undergoing cardiac surgery (December 2017 to December 2019).

INTERVENTIONS

None. Measurement and Main Result: Preoperative echocardiographic reports and intraoperative echocardiographic images of the participants were studied. The correlation between the stage of left ventricular diastolic dysfunction and strain-based indices (including early diastolic peak longitudinal strain and tissue deceleration time) were evaluated. Early diastolic peak longitudinal strain rate significantly correlated with the stage of diastolic dysfunction (r = -0.7 and p < 0.0001). Tissue deceleration time significantly correlated with the stage of diastolic dysfunction in patients with diastolic abnormality (r = -0.4 and p = 0.02). When patients with normal diastolic function were included, this correlation was not significant (r= -0.25 and p = 0.05).

CONCLUSIONS

Intraoperatively measured early diastolic peak longitudinal strain rate and tissue deceleration time correlated with the severity of diastolic dysfunction in patients undergoing cardiac surgery.

How to Reliably Detect Ischemia in the Intensive Care Unit and Operating Room

Detection of myocardial ischemia in the perioperative period is important because it allows for intervention that may prevent progression of ischemia to myocardial infarction. Perioperative ischemia is also an important predictor of adverse cardiovascular outcomes. Patients should first be stratified according to their risk of having cardiovascular disease by identifying major, intermediate, and minor predictors of adverse cardiovascular outcome. Electrocardiographic (ECG) monitoring for ischemia is inexpensive and noninvasive, but may not be applicable to all patients and is not perfectly sensitive or specific. Modern operating room monitors can automate ST segment monitoring and be set to alarm if changes occur. Increases in central venous pressure and pulmonary artery pressure can be caused by myocardial ischemia, but have been shown to be very insensitive compared to ECG. Also, detection of these hemodynamic changes requires insertion of invasive monitoring devices. Transesophageal echocardiography can be used to detect myocardial ischemia by identifying changes in regional wall motion. These transesophageal echocardiography changes occur sooner and more frequently than ECG changes, but require greater knowledge and skill to properly interpret.

Case report: transesophageal echocardiography detected severe regional wall motion abnormalities signifying failed reimplantation of an anomalous left main coronary artery

PURPOSE

Anomalous coronary arteries comprise a spectrum ranging from benign to fatal. The most ominous lesion that occurs is the left main coronary artery (LMCA) originating from the opposite aortic sinus. This defect usually presents as sudden death in a healthy young adult immediately after exercise. We report a case of reimplantation of an anomalous LMCA, discovered in a 15-yr-old girl during investigations for atypical chest pain.

CLINICAL FEATURES

The intraoperative transesophageal echocardiography (TEE) confirmed that the anomalous LMCA originated from the right aortic sinus. The anomalous LMCA was reimplanted to the left aortic sinus, but the patient could not be weaned from cardiopulmonary bypass because of severe hypotension. The TEE demonstrated severe regional wall motion abnormalities (RWMA) in the territory of the LMCA with akinesis of the septal, antero-septal, anterior, and lateral walls. Using TEE, flow could not be seen in the reimplanted LMCA, hence, the differential diagnosis was established as failed reimplantation of the LMCA, coronary air embolism, or poor myocardial preservation, but the latter two causes were extremely unlikely. Surgical inspection of the reimplanted LMCA did not reveal a correctable problem. A left internal mammary artery to proximal left anterior descending (LAD) artery graft was completed with resolution of the previous RWMA. Recovery of function in the lateral wall confirmed retrograde flow from the LAD into the circumflex artery.

CONCLUSIONS

Transesophageal echocardiography was critical in rapidly determining the cause of hemodynamic instability following this uncommon operation. Despite the availability of newer techniques to detect and quantify RWMA, the assessment of wall motion and contractility remains subjective.

Perioperative echocardiography: two-dimensional and three-dimensional applications

Perioperative echocardiography is an essential skill for today's cardiac anesthesiologist and a driving force for innovation and accomplishment for the future of the subspecialty. Real-time three-dimensional transesophageal echocardiography (RT3-D TEE) will dominate the future practice of perioperative echocardiography, but transthoracic echocardiography (TTE) will grow in application, as will contrast echocardiography. Hand-held ultrasonongraphs will rival current machines in capabilities and make it possible for TTE to become the stethoscope of the future for cardiac anesthesiologists.

Monitoring of whole-body hyperthermia with transesophageal echocardiography (TEE)

Hyperthermia induces tumor cell death by a spectrum of tumor tissue changes. As whole-body hyperthermia (WBH) can cause cardiovascular complications, especially when cardiotoxic cytostatic agents are administered, invasive cardiovascular monitoring during WBH is necessary. WBH requires a great deal of expenditure and bears the risk of severe toxicity. Furthermore cardiovascular stress, alterations of cardiac index and systemic vascular resistance are major problems during WBH. The purpose of this prospective study was to evaluate cardiovascular changes in patients undergoing WBH under general anesthesia using transesophageal echocardiography (TEE) with special focus on left ventricular function.

METHODS

Hemodynamic parameters were measured with standard monitoring and TEE at defined time points in 20 patients (ASA III) undergoing WBH: M37 (baseline, body temperature: 37 degrees C) after induction of anesthesia, M39 during warming up (39 degrees C), M41.8 at plateau level (41.8 degrees C), M38 during cooling period (38 degrees C).

RESULTS

Invasive monitoring and TEE measurements showed signs of hyperdynamic circulation with significant increase of the heart rate (73.6 +/- 13.7 min(-1) (M37), 104.6 +/- 13.0 min(-1) (M41.8)) and significant decrease of mean blood pressure (74.9 +/- 15.3 mmHg (M37), 65.3 +/- 11.2 mmHg (M41.8)). Cardiac index (CI) nearly doubled and stroke volume index (SVI) increased significantly from M37 to M41.8. Cardiac contractility, fractional area change (FAC) and ejection fraction (EF) increased. At M38 CI, SVI, FAC and EF showed a tendency to decrease compared to M41.8 but remained elevated compared to M37.

CONCLUSION

Patients undergoing WBH showed typical signs of hyperdynamic circulation without impairment of left ventricle which could be monitored excellently by TEE. We recommend using TEE especially in patients with an increased cardiac risk.

Assessment of Left Ventricular Global and Segmental Systolic Function with Transesophageal Echocardiography

The evaluation of LV global and segmental systolic function is a primary application for perioperative TEE. Although the practical techniques customarily used for these applications have limitations, they afford direct measures of function not otherwise available to the clinician in the operating room or intensive care setting.

Complications of major aortic and lower extremity vascular surgery

Atheromatous disease and invasive intervention of the aortoiliac and distal arteries are common. Morbidity and mortality have been reduced through understanding and management of patient risk factors. Complications of this form of treatment affect all organ systems; mortality is most frequently caused by a cardiovascular complication (eg, myocardial infarction). Infection, leading to aortoenteric fistula is a dreaded complication, and paraplegia, though rare, is a devastating outcome. Multiorgan failure and death may result from a systemic inflammatory response syndrome. Vascular surgery for infrainguinal disease also has a significant cardiovascular complication rate. Resulting complications may affect all organs; loss of an extremity may occur. The first part of this article reviews perioperative and postoperative complications of open aortic repair and lower-extremity revascularization and addresses the issue of regional anesthesia for major vascular surgery. The second part reviews endovascular aortic repair (EVAR). EVAR is a new intervention that combines surgery and radiology. Complications of EVAR are similar to open repair, but early results suggest they may be less frequent. New technology leads to new complications; endoleaks, migration of the endoprosthesis, and surgical conversion are unique to EVAR. The benefits of EVAR may be less blood loss, shorter hospitalization, and less cardiovascular stress; the risks may be aneurysm recurrence, prolonged surveillance and repeated secondary procedures. The development of EVAR, the complications, and the anesthesia-related concerns of EVAR, including its use in management of acute abdominal aortic aneurysm are reviewed.

Intraoperative monitoring during vascular surgery

The principal objectives of intraoperative monitoring are to improve perioperative outcome, facilitate surgery and reduce adverse events, using continuously collected data of cardiopulmonary,neurologic and metabolic function to guide pharmacologic and physiologic therapy. Although sophisticated and reliable apparatus may be used to collect these data they are useless, or even harmful, without proper interpretation. This article provides a comprehensive overview of recent publications on the history,philosophy, and semantics of monitoring.

Mechanisms of hemodynamic changes during off-pump coronary artery bypass surgery

PURPOSE

To describe the mechanisms of hemodynamic changes during off-pump coronary artery bypass graft surgery (OP-CABG).

SOURCE

Pertinent medical literature in the English and French languages was identified through a Medline computerized literature search and a manual search of selected articles, using off-pump coronary artery surgery, beating heart surgery, hemodynamic, and transesophageal echocardiography as key words. Human and animal studies were included.

PRINCIPAL FINDING

Hemodynamic variations in OP-CABG may be due to mobilization and stabilization of the heart, or myocardial ischemia occurring during coronary occlusion. Suction type and compression type stabilizers produce hemodynamic effects through different mechanisms. Heart dislocation (90 degrees anterior displacement) and compression of the right ventricle to a greater extent than the left ventricle are responsible for hemodynamic alterations when using suction type stabilizers. Compression of the left ventricular outflow tract and abnormal diastolic expansion secondary to direct deformation of the left ventricular geometry are proposed mechanisms for hemodynamic derangements with compression type stabilizer. Coronary occlusion during the anastomosis can have additional effects on left ventricular function, depending on the status of collateral flow. The value and limitations of electrocardiographic (ECG), hemodynamic and echocardiographic monitoring modalities during OP-CABG are reviewed.

CONCLUSIONS

In summary, hemodynamic changes which can either be secondary to the stabilization technique or to transient ischemia represent an important diagnostic challenge during off-bypass procedures. The mechanism can vary according to the stabilization system. Current monitoring such as ECG and hemodynamic monitoring are used but remain limited in establishing the cause of hemodynamic instability. Transesophageal echocardiography is used in selected patients to diagnose the etiology of hemodynamic instability and can direct therapy, particularly in those with severe myocardial systolic and diastolic dysfunction, mild to moderate mitral regurgitation, or for patients who are unstable during the procedure.

Segmental wall motion abnormalities during telerobotic totally endoscopic coronary artery bypass grafting

In addition to single-lung ventilation (SLV), intrathoracic CO2 insufflation is mandatory for adequate exposure during totally endoscopic coronary artery bypass grafting. With transesophageal echocardiography, we investigated biventricular myocardial wall motion in 25 patients with isolated disease of the left anterior descending coronary artery who underwent totally endoscopic coronary artery bypass grafting with the "Da Vinci" robotic surgical system. At distinct time points during the operation, a cine loop of both ventricles was registered from a transgastric mid-short-axis view. Myocardial wall motion analysis was performed according to an established segmentation model of the left ventricle and to an established five-point scale for wall motion (1, normal; 5, dyskinesia). Significant alterations from preoperative baseline wall motion were visible in the septal, inferior, and anterior segments of the left ventricle at some time during the prebypass period, combined with a markedly decreased PaO2 under SLV and increased intrathoracic pressure. The same findings applied to the right ventricle; however, wall motion abnormalities were more pronounced here. After myocardial revascularization, weaning from cardiopulmonary bypass, CO2 deflation, and return to double-lung ventilation, myocardial wall motion recovered to baseline values. Clinically significant hemodynamic instability did not occur. The data suggest that robot-assisted coronary artery bypass grafting leads to significant prebypass alterations of biventricular segmental wall motion. On the basis of our data, it cannot be definitively stated whether the observed results were due to reduced oxygenation during SLV and thus "real" myocardial ischemia, intrathoracic CO2 insufflation with positive pressure leading to mechanical compromise of the heart, absolute or relative hypovolemia, or a combination of these factors. However, in this cohort, which consisted of patients with single-vessel disease and good ventricular function, these changes were of limited clinical relevance.

IMPLICATIONS

Segmental myocardial wall motion was evaluated with transesophageal echocardiography during robot-assisted totally endoscopic coronary artery bypass grafting. Significant biventricular segmental wall motion abnormalities occurred before cardiopulmonary bypass under single-lung ventilation and carbon dioxide insufflation. The changes in myocardial wall motion were of limited clinical relevance.

Low-dose dobutamine stress and left ventricular wall motion monitored with transesophageal echocardiography versus hemodynamic data derived from pulmonary artery catheterization in patients scheduled for CABG

BACKGROUND

The clinical acceptance of transesophageal echocardiography (TEE) as a monitoring technique for left ventricular function in open-heart surgery is now widely recognized. This technique's accurate imaging capabilities have been found to improve the information obtained by the pulmonary catheter (PAC) and thermodilution. TEE is also a less invasive technique than PAC. However, because it is costly, further comparisons between the techniques are worthwhile. This study compares hemodynamic data obtained with PAC and how these correspond to echocardiography data using TEE.

METHODS

Twenty-four anesthetized patients undergoing elective coronary artery bypass grafting (CABG) were studied. They were monitored with PAC and TEE. A low-dose dobutamine protocol for viability was used with doses of 5 and 10 microg x kg(-1) x min(-1). Endpoints for this stimulation included on-line visual change in left ventricle wall motion (LVWM), increased arterial blood pressure more than 40 mmHg, a heart rate (HR) increase of more than 20%, or ST depression on ECG exceeding 0.2 mV. Visual assessment of LVWM using the transgastric short-axis view was made off line by a blinded observer. Six segments were used and a wall motion score was made at each level of dobutamine stimulation.

RESULTS & CONCLUSION

Two patients reached the endpoint for elevated blood pressure with a dobutamine dose of 5 microg x kg(-1) x min(-1), and twenty-two patients were stimulated to 10 microg x kg(-1) x min(-1). There were significant increases in cardiac output (CO), stroke volume (SV), systolic arterial pressure (SAP), mean arterial pressure (MAP), diastolic arterial pressure (DAP), pulmonary capillary wedge pressure (PCWP) and left ventricle stroke work index (LVSWI), but not in HR and systemic vascular resistance (SVR). Moreover, the LVWM increased significantly, but not fractional area change (FAC). The main finding, however, was the increase in SV with an accompanying improvement in LVWM, suggesting that visual assessment of improved wall motion could substitute PAC and thermodilution monitoring in clinical settings which demand a quick estimate of left ventricular performance.

The adequacy of basic intraoperative transesophageal echocardiography performed by experienced anesthesiologists

Transesophageal echocardiography (TEE) may improve intraoperative decision-making and patient outcome if it is performed and interpreted correctly. After revising our TEE examination to fulfill the published guidelines for basic TEE practitioners, we prospectively evaluated the ability of our cardiac anesthesiologists (all very experienced with TEE) to record and interpret this revised examination. Educational aids and regular TEE performance feedback were provided to the anesthesiologists. Their interpretations were compared with the independently determined results of experts. Compared with their own historical controls (42% recording rate), all anesthesiologists showed significant improvement in their ability to record a basic intraoperative TEE examination resulting in 81% (P < 0.0001) of all required images being recorded: 88% before cardiopulmonary bypass, 77% immediately after bypass, and 64% after chest closure. Seventy-nine percent of the images recorded at baseline were correctly interpreted, 6% were incorrectly interpreted, and 15% were not evaluated. Our attempt to assess compliance with published guidelines for basic intraoperative TEE resulted in a marked improvement in our intraoperative TEE practice. Most, but not all, standard cross-sections are recorded or interpreted correctly, even by highly experienced and motivated practitioners.

IMPLICATIONS

Experienced cardiac anesthesiologists can obtain and correctly interpret most basic intraoperative transesophageal echocardiograms.

Myocardial ischemia detected by transesophageal echocardiography in a patient undergoing peripheral vascular surgery

Prevention and early treatment of myocardial ischemia remain among the primary goals of the anesthesiologist taking care of high-risk patients, such as those undergoing vascular surgery. Guidelines have been published to assist in directing preoperative evaluation and optimization of cardiovascular status. Although perioperative monitoring allows early detection of ischemic events, all monitors have limitations that must be understood before they can be used effectively. We present a case of severe intraoperative myocardial dysfunction detected only by transesophageal echocardiography in a patient undergoing a peripheral vascular procedure. Preoperative and intraoperative management is also discussed.

Minimally invasive direct coronary artery bypass grafting: changes in anesthetic management and surgical procedure

OBJECTIVE

The authors hypothesized that changes in surgical procedures for minimally invasive direct coronary artery bypass grafting (MIDCAB) have led to changes in anesthetic management with a resultant decrease in the complexity of care.

DESIGN

Retrospective observational study.

SETTING

University teaching hospital.

PARTICIPANTS

Review of the records of 60 patients who underwent MIDCAB surgery.

MEASUREMENTS AND MAIN RESULTS

Data included preoperative demographics, perioperative anesthetic management, and postoperative cardiac and noncardiac issues and complications. Two groups were formed: in group I, a coronary stabilizer (CS) was not used, and in group II, it was. With the exception of a greater incidence of those with no preoperative comorbidities in group II (CS), there were no differences between the two groups with respect to demographics or preoperative variables. A surgical design called H-graft was used in a greater number of group II (CS) patients, whereas a direct anastomosis was performed in the majority of group I patients. Use of pharmacologically induced bradycardia/asystole has not been performed after the introduction of the CS. The use of central venous catheters (instead of pulmonary artery catheters) and single-lumen (v double-lumen) endotracheal tubes was greater in group II (CS) patients. Despite changes in intraoperative management, there was no significant change in the incidence of postoperative complications, intensive care unit stay, and hospital stay between groups I and II. New-onset atrial fibrillation was the most common postoperative complication (13 of 56 patients; 23%). Three of 24 patients (12.5%) who received intraoperative magnesium experienced atrial fibrillation compared with 10 of 32 patients (31%) who did not receive magnesium.

CONCLUSIONS

The complexity of anesthetic technique has decreased since the onset of MIDCAB surgery. The decrease in complexity may be related to changes in surgical design and technology.

The influence of transoesophageal echocardiography on intra-operative decision making. A European multicentre study. European Perioperative TOE Research Group

The role of transoesophageal echocardiography (TOE) in anaesthesia remains controversial because it is a rapidly evolving technique with few proven benefits and considerable cost. Recently, the Society of Cardiovascular Anaesthesiologists has published practice guidelines for the use of peri-operative TOE. To determine the current role of transoesophageal echocardiography and the relative impact of category-based transoesophageal echocardiographic indications the present study investigated its use in seven Western European countries. The study sample was taken from a prospective cohort of 224 patients with acute or chronic haemodynamic disturbances or at risk of myocardial ischaemia. All patients were monitored with two-lead electrocardiography and radial and pulmonary artery catheters, as well as biplane or multiplane transoesophageal echocardiography. A total of 2232 clinical interventions were made in these patients. The most frequently observed intervention was the administration of a fluid bolus (45% of all interventions). Overall, transoesophageal echocardiography was the most important guiding factor in 560 (25%) interventions. It was the most important monitor in guiding the following therapeutic interventions: anti-ischaemic therapy--207 of 372 interventions (56%); fluid administration--275 of 996 (28%) interventions; vasopressor or inotrope administration--56 of 316 (16%) interventions; vasodilator therapy--six of 142 (4%) interventions and depth of anaesthesia--four of 211 (2%) interventions. We found that transoesophageal echocardiography is frequently influential in guiding clinical decision making and is used most frequently for category II indications but category I indications were associated with more frequent change in management.

Intraoperative transoesophageal echocardiography: impact on adult cardiac surgery

Although multiple case reports have demonstrated the capability of transoesophageal echocardiography (TOE) to detect unsuspected cardiac pathology with important therapeutic implications, few studies have examined the effect of real-time interpretation of routine TOE on clinical management of a typical series of cardiac surgery patients. To assess the impact of intraoperative TOE on cardiac surgical management, we conducted a prospective observational study on 238 consecutive patients undergoing intraoperative TOE during adult cardiac surgery. Potentially important new diagnostic information was detected in 39 of 184 (21%) routine and in 53 of 54 requested TOE examinations, and led directly to different surgical procedures in 11 of 184 (6%) routine and in 12 of 54 (22%) requested TOE examinations. Our data suggests that intraoperative TOE may be a valuable tool in the routine management of adult cardiac surgical patients.

Anesthetic management and perioperative surveillance

The intraoperative management of the high-risk patient has received a great deal of attention and research during the past decade. Based on the available evidence, there appears to be no one best anesthetic technique or agent. More importantly, the goals of intraoperative management are to avoid myocardial ischemia, which include preventing tachycardia, and maintaining normothermia and adequate hematocrit. Perioperative monitoring includes transesophageal echocardiography, pulmonary artery catheter and ST segment monitoring. Perioperative pharmacological treatment with alpha-2 agonists and beta-adrenergic blocking agents are associated with a reduced incidence of perioperative myocardial ischemia and improved long-term survival, respectively. Future research will be required to determine whether prophylactic therapy or early treatment of perioperative myocardial ischemia will lead to improved outcome.

Myocardial ischemia and adverse cardiac outcomes in cardiac patients undergoing noncardiac surgery with sevoflurane and isoflurane. Sevoflurane Ischemia Study Group

Sevoflurane is associated with less tachycardia and coronary vasodilation than isoflurane and thus might be associated with less myocardial ischemia. This multicenter study examined the incidence of myocardial ischemia and adverse cardiac outcomes in adults (40-87 yr) with cardiac disease having elective noncardiac surgery. Patients were randomized to receive either sevoflurane (S) (n = 106) or isoflurane (I) (n = 108) in conjunction with sodium thiopental, vecuronium, fentanyl, and 50%-70% N2O. Intraoperative hemodynamics were maintained within 20% of awake baseline with standard drugs. A Holter monitor was applied 3-24 h before surgery and maintained until 48 h after surgery. Electrocardiograms and blood samples for analysis of the MB isoenzyme fraction of creatine phosphokinase were obtained preoperatively and daily for 48 h postoperatively. Anesthetic exposure (1.79 +/- 0.15 [mean +/- SE] minimum alveolar concentration-hour) and duration of surgery (219 +/- 13 min) did not differ between groups. The incidence of ischemia in the pre-, intra- and postoperative periods, adverse cardiac outcomes (18% occurrence), intraoperative hemodynamic variations (+/-20% change from ward baseline), and administration of adjunct cardiovascular medications were similar between groups. In cardiac patients having noncardiac surgery, sevoflurane was comparable to isoflurane with respect to the incidence of intra- and postoperative myocardial ischemia and in the frequency of adverse cardiac outcomes.

IMPLICATIONS

Surgical patients with heart disease are at risk of heart complications, some of which could be induced by an anesthetic. We compared the incidence of cardiac complications between patients receiving sevoflurane and isoflurane. We found that the frequency of additional heart problems in cardiac patients receiving sevoflurane was not different from that associated with isoflurane.

Detection of myocardial ischemia by transesophageal echocardiographically determined changes in left ventricular area in patients undergoing coronary artery bypass surgery

STUDY OBJECTIVE

To evaluate left ventricular (LV) dimensions and function during myocardial ischemic episodes in anesthetized patients undergoing coronary artery bypass surgery.

DESIGN

Prospective, nonrandomized study.

SETTING

Large, medical school-affiliated tertiary-care medical center.

PATIENTS

36 adults undergoing elective primary coronary artery bypass surgery.

INTERVENTIONS

Transesophageal atrial pacing for 3 to 5 minutes at heart rates (HRs) of 65, 70, 80, and 90 beats per minute.

MEASUREMENTS AND MAIN RESULTS

Arterial, pulmonary artery, and venous pressures, transesophageal echocardiographic (TEE) determined LV end-diastolic (EDA) and end-systolic (ESA) areas, and fractional area change (FAC = [FDA-ESA]/EDA). Myocardial ischemia determined as at least 1 mm ST segment deviation at J + 60 milliseconds from 12-lead electrocardiography (ECG) and TEE detected new LV regional wall motion abnormalities. Biplane TEE images were recorded on videotape, and LV EDA and ESA were determined with planimetry from images of the LV short axis. Myocardial ischemia was observed in 12 patients. In these patients, EDA and ESA were higher and FAC lower than those patients without ischemia at the same HR. There were no differences between patients with and without myocardial ischemia with regard to pulmonary artery occlusion pressure, stroke volume, or other hemodynamic variables. The positive predictive values were best for ESA (67%) and EDA (58%), and least for FAC (18%). Negative predictive values were highest for ESA (85%) and EDA (80%), and least for FAC (47%).

CONCLUSIONS

In anesthetized patients undergoing coronary artery bypass surgery, myocardial ischemia observed during atrial pacing results in increases in LV dimensions and decreases in FAC compared with values in patients without ischemia. These results support further investigations of the clinical usefulness of monitoring LV EDA and LV ESA with TEE as a method of myocardial ischemia detection.

Advances in anesthesia for cardiac surgery: an overview for the 1990s

Anesthetic care for patients undergoing cardiac surgery has changed dramatically in the past 10 years. Examples of such change include same-day admissions, "fast-track" protocols, selective use of pulmonary artery catheters, transesophageal echocardiography, and the introduction of new drugs such as phosphodiesterase inhibitors and antifibrinolytic agents. Under pressure from our peers and those funding health care, we are making major efforts to reduce costs and the length of hospitalization while maintaining high quality of care.

Assessment of left ventricular function and hemodynamics with transesophageal echocardiography

Transesophageal echocardiography (TEE) plays an important role in the evaluation of left ventricular function and hemodynamics in the critical care setting. The technique provides immediate data regarding regional myocardial ischemia, global ventricular function, volume, and the presence of cardiac tamponade. This article outlines the role of TEE in the evaluation of left ventricular function in the intensive care unit and presents practical information for the use of TEE in evaluating systolic function, diastolic function, and cardiac tamponade.

Evaluation of a semiautomatic contour detection approach in sequences of short-axis two-dimensional echocardiographic images

Quantitative analysis of echocardiographic sequences has been limited by time-consuming and strenuous manual tracing approaches. To circumvent these disadvantages, we have developed the EchoCardiographic Measurement System (ECHO-CMS). ECHO-CMS employs the robust, model-based Minimum Cost Contour Tracking technique for semiautomatic detection of left ventricular (LV) endocardial contours in sequences of consecutive echocardiographic images. An evaluation study was carried out on 20 short-axis patient studies (10 transesophageal and 10 transthoracic studies), each consisting of 16 consecutive images covering approximately one cardiac cycle. The LV endocardial contours in the 320 images were analyzed both by manual tracing and semiautomatically. In addition, interobserver and intraobserver variabilities were determined for both techniques in two patients (32 images). Manual editing was required in only 57 (18%) of all 320 contours detected. Average processing time per patient for manual tracing was 25 minutes (of which 18 1/2 minutes was for drawing and corrections) and for semiautomatic tracing it was only 5 1/2 minutes (of which just 1 1/2 minutes was for corrections). Regression analysis showed excellent correspondence between manual and semiautomatic tracing: semiautomatic = 1.01 manual + 5.58%; r = 0.989; standard error of the estimate = 11.9% (n = 320 contours). Interobserver and intraobserver variabilities were smaller for semiautomatic than for manual tracing, although not in all cases statistically significant. In conclusion, semiautomatic LV short-axis endocardial contour detection by ECHO-CMS provides contours that are highly similar to those drawn by an expert; it is five to 10 times faster than manual tracing and reduces intraobserver and interobserver variabilities. This demonstrates that ECHO-CMS is a useful tool for clinical echocardiographic research studies.

Transesophageal echocardiography in myocardial ischemia: a review

This article reviews established as well as emerging fields in the application of transesophageal echocardiography (TEE) in the investigation of myocardial ischemia. TEE already has a well defined and established role in stress echocardiography in patients with poor transthoracic acoustic window, and in the detection of intraoperative myocardial ischemia in cardiac and noncardiac surgery. The evaluation of right ventricular ischemia and infarction and the assessment of coronary flow reserve (CFR) are relatively new fields in the application of TEE and the potential of this technique has not yet been fully evaluated. The evidence collected and reviewed in this article is still preliminary but it presupposes a significant role of TEE in the diagnosis and pathophysiological assessment of myocardial ischemia.

Choice of anesthesia and intraoperative monitoring for lower extremity revascularization

The prevalence of significant coronary artery disease re-enforces the importance of careful preoperative and intraoperative management in patients undergoing lower extremity revascularization. This article presents a practical approach toward the evaluation of anesthetic risk and the proper use of anesthetic agents and monitoring devices to minimize morbidity. The role of general and regional anesthetic agents is discussed, and complications of both techniques are presented.

Detection of intraoperative myocardial ischaemia--a comparison among electrocardiographic, myocardial metabolic, and haemodynamic measurements in patients with reduced ventricular function

This study determined the sensitivity and specificity of haemodynamic and ECG monitors to detect the development of intraoperative myocardial ischaemia utilizing myocardial lactate production as the standard. In 29 patients with reduced ejection fraction (0.27-0.50) undergoing coronary artery revascularization, measurements were made at the awake, post-induction, post-intubation, first skin incision, post-sternotomy, pre-protamine, immediately post-cardiopulmonary bypass, and skin suture intervals. At each interval, measurement of a haemodynamic profile (including pulmonary artery occlusion (PAOP) and central venous (CVP) pressures, heart rate, and pressure rate quotient); myocardial lactate extraction and flux; changes in ST segments in ECG leads, V5 and II utilizing a Siemens 1280 intraoperative monitor, and a Marquette 8500 Holter monitor utilizing leads V5, V2, and AVF were made. "Ischaemia" was considered to be present when myocardial lactate production (MLP) occurred, PAOP or CVP increased by 5 mmHg above the baseline value, the pressure rate quotient was < 1, or ST segment deviation (> 1 mm) occurred in any lead for > 1 min. Variables positive when MLP was positive were the pressure rate quotient (sensitivity 32.8%, specificity 71.9%), CVP (sensitivity 10.9%, specificity 92.6%), and PAOP (sensitivity 1.6%, specificity 99.2%). Holter monitoring had a 100% positive predictive value but poor sensitivity (1.6%). The ECG (Lead V5 + II) measures of ischaemia were insensitive (17.5%) and relatively non-specific (87.7%). We conclude that, in this patient group and using myocardial lactate production as the standard, the pressure rate quotient, elevations in CVP or PAOP, or ST segment changes are insensitive measures of intraoperative myocardial ischaemia.