Perioperative echocardiography for non-cardiac surgery: what is its role in routine haemodynamic monitoring?
2009; Elsevier BV; Volume: 102; Issue: 6 Linguagem: Inglês
10.1093/bja/aep100
ISSN1471-6771
AutoresAlexander Ng, Justiaan Swanevelder,
Tópico(s)Hemodynamic Monitoring and Therapy
ResumoPerioperative echocardiography enables direct visualization of the chambers of the heart, its valves, and the major connecting vessels (aorta, pulmonary artery, pulmonary veins, and vena cavae). Many aspects of cardiac function may be measured and monitored by transoesophageal (TOE) and transthoracic (TTE) echocardiography. In cardiac anaesthesia, echocardiography has become an established imaging modality.1Kneeshaw JD Transoesophageal echocardiography (TOE) in the operating room.Br J Anaesth. 2006; 97: 77-84Abstract Full Text Full Text PDF PubMed Scopus (37) Google Scholar With recent proposed changes in training, the goalposts for perioperative echocardiography appear to have extended to include non-cardiac surgery.2Price S Via G Sloth E et al.Echocardiography practice, training and accreditation in the intensive care: document for the World Interactive Network Focused on Critical Ultrasound (WINFOCUS).Cardiovasc Ultrasound. 2008; 6 (doi:10.1186/1476-7120-6-49): 49Crossref PubMed Scopus (174) Google Scholar This Editorial examines the feasibility of using perioperative echocardiography in routine non-cardiac practice. It adopts a framework similar to that for diagnostic tests in the laboratory,3Walley T Evaluating laboratory diagnostic tests. International collaboration to set standards and methods is urgently needed.Br Med J. 2008; 336: 569-570Crossref PubMed Scopus (23) Google Scholar that is to say, clinical validity (the ability to detect presence or absence of disease), clinical usefulness (does the test lead to better patient outcomes?), safety, education, and economics. The validity of TOE as a monitor may be illustrated using a model of infective endocarditis in which multiple structural abnormalities, for example, vegetations, abscesses, and pseudoaneurysms may be seen. In a study of 29 patients who underwent cardiac surgery for infective endocarditis, the sensitivity and specificity of TOE for visualization of vegetations compared with intraoperative findings were 96% and 100%, respectively. Equally high values (89% and 100%, respectively) were obtained for detection of abscess and pseudoaneurysm. These values were similar to those obtained by computed tomography in the same patients.4Feuchtner GM Stolzmann P Wolfgang D et al.Multislice computed tomography in infective endocarditis.J Am Coll Cardiol. 2009; 53: 436-444Crossref PubMed Scopus (297) Google Scholar For assessment of valvular function, imaging by TOE and by magnetic resonance imaging (MRI) is equivalent. Compared with intraoperative findings of mal-apposition of mitral valve leaflets, TOE had a sensitivity of 75% and specificity of 88%. The values for MRI were 71% and 88%, respectively.5Stork A Franzen O Ruschewski H et al.Assessment of functional anatomy of mitral valve in patients with mitral regurgitation with cine magnetic resonance imaging: comparison with transesophageal echocardiography and surgical results.Eur Radiol. 2007; 17: 3189-3198Crossref PubMed Scopus (32) Google Scholar These favourable findings for TOE in the heart contrast with those for TOE in the major vessels. In a study of patients requiring pulmonary embolectomy, TOE was found to have a specificity of 95% but a sensitivity of only 26%.6Rosenberger P Shernan SK Body SC Eltzschig HK Utility of intraoperative transoesophageal echocardiography for diagnosis of pulmonary embolism.Anesth Analg. 2004; 99: 12-16Crossref PubMed Scopus (83) Google Scholar Furthermore, in a meta-analysis of six studies evaluating TOE for detection of atherosclerosis in the ascending aorta, the specificity was 99%, whereas the sensitivity was only 21%.7Van Zaane B Zuithoff NP Reitsma JB Bax L Nierich AP Moons KG Meta-analysis of the diagnostic accuracy of transesophageal echocardiography for assessment of atherosclerosis in the ascending aorta in patients undergoing cardiac surgery.Acta Anaesthesiol Scand. 2008; 52: 1179-1187Crossref PubMed Scopus (30) Google Scholar The use of TTE also has validity. In critical care practice, TTE has been used to investigate causes of haemodynamic instability. In a study of 100 patients, imaging was deemed to be adequate in 99%, with sensitivity and specificity for a cardiac cause of 100% and 95%, respectively. Typical causes of haemodynamic instability were ventricular dysfunction, tamponade, rupture of myocardium, and obstruction of the left ventricular outflow tract.8Joseph MX Disney PJS Da Costa R Hutchison SJ Transthoracic echocardiography to identify or exclude cardiac cause of shock.Chest. 2004; 126: 1592-1597Abstract Full Text Full Text PDF PubMed Scopus (167) Google Scholar For risk stratification of patients who are at risk of myocardial infarction and death, stress echocardiography (TTE) before elective non-cardiac surgery has been found to provide diagnostic information. In a meta-analysis comprising 25 echocardiographic and 50 nuclear diagnostic tests in patients who had non-cardiac surgery, the positive likelihood ratio, that is to say, the ratio of the true-positive rate (sensitivity) to the false-positive rate (1-specificity) was obtained. The likelihood ratio of 4.09 (95% CI 3.21–6.56) for a cardiac event with stress echocardiography was superior to that of 1.83 (95% CI 1.59–2.10) for thallium imaging.9Beattie WS Abdelnaem E Wijeysundera DN Buckley DN A meta-analytic comparison of preoperative stress echocardiography and nuclear scintigraphy imaging.Anesth Analg. 2006; 102: 8-16Crossref PubMed Scopus (115) Google Scholar In addition, stress echocardiography was found to be a better predictor of an uneventful perioperative period than thallium scanning. The likelihood ratio for absence of a cardiac event was, conversely, lower for stress echocardiography (0.23, 95% CI 0.17–0.32) than for thallium scanning (0.44, 95% CI 0.36–0.54). Perioperative echocardiography has been reported during a variety of types of non-cardiac surgery, that is to say, vascular, endovascular, transplant, obstetrics, trauma, and orthopaedics.10Mahmood F Christie A Matyal R Transoesophageal echocardiography and noncardiac surgery.Sem Cardiothorac Vasc Anesth. 2008; 12: 265-289Crossref PubMed Scopus (50) Google Scholar It is believed to be clinically useful as it has influenced intraoperative anaesthetic decisions, particularly in patients with increased risk factors for myocardial ischaemia or haemodynamic instability. In a prospective observational case series of 98 patients undergoing abdominal surgery, the opinion of the anaesthetists was that TOE led to useful changes in intraoperative management such as administration of fluids, vasopressors, vasodilators, and beta-blockers. In some patients, use of the pulmonary artery catheter was obviated.11Schulmeyer MCC Santelices E Vega R Schmied S Impact of intraoperative transoesophageal echocardiography during noncardiac surgery.J Cardiothorac Vasc Anesth. 2006; 20: 768-771Abstract Full Text Full Text PDF PubMed Scopus (62) Google Scholar Similarly, in another case series comprising 90 patients undergoing vascular, visceral, and chest surgery, TOE was associated with changes in drug (47%) and fluid therapy (24%).12Hofer CK Zollinger A Rak M et al.Therapeutic impact of intraoperative transoesophageal echocardiography during noncardiac surgery.Anaesthesia. 2004; 59: 3-9Crossref PubMed Scopus (74) Google Scholar Cardiac arrests occur occasionally during non-cardiac surgery. In this situation, TOE has been reported to be helpful for diagnosis and for establishing rescue therapy. In a prospectively collected case series of 125 965 patients, 10 cardiac arrests occurred.13Lin T Chen Y Lu C Wang M Use of transoesophageal echocardiography during cardiac arrest in patients undergoing elective non-cardiac surgery.Br J Anaesth. 2006; 96: 167-170Abstract Full Text Full Text PDF PubMed Scopus (38) Google Scholar In these patients, TOE was able to detect abnormalities in ventricular wall motion and myocardial infarction (confirmed by increase in troponin). It was also possible to identify pulmonary embolism and severe hypovolaemia. In another case series of patients who suffered a cardiac arrest during non-cardiac surgery, TOE was also found to be useful. Of 22 patients scanned, a primary diagnosis was identified by TOE in 19 patients; these included myocardial ischaemia, thromboembolism, pericardial tamponade, and hypovolaemia. Patients went on to have definitive rescue treatment such as emergency coronary artery surgery, intra-aortic balloon support, pulmonary embolectomy, pericardiotomy, and fluid resuscitation.14Memtsoudis SG Rosenberger P Loffler M et al.The usefulness of transoesophageal echocardiography during intraoperative cardiac arrest in noncardiac surgery.Anesth Analg. 2006; 102: 1653-1657Crossref PubMed Scopus (135) Google Scholar In addition to the operating theatre, echocardiography has been shown to be useful in critical care.15Jensen MB Sloth E Larsen KM Schmidt MB Transthoracic echocardiography for cardiopulmonary monitoring in intensive care.Eur J Anaesthesiol. 2004; 21: 700-707Crossref PubMed Google Scholar For example, in a case series comprising 224 TOE and TTE scans in 217 patients, change in management, that is to say, administration of fluids, inotropes and other drugs, occurred in 51% as a direct consequence of the information provided by echocardiography.16Orme RM Oram MP McKinstry CE Impact of echocardiography on patient management in the intensive care unit: an audit of district general hospital practice.Br J Anaesth. 2009; 102: 340-343Abstract Full Text Full Text PDF PubMed Scopus (100) Google Scholar In general, echocardiography is believed to be helpful for the investigation and treatment of haemodynamic instability in critical care.17Subramaniam D Talmor D Echocardiography for management of hypotension in the intensive care unit.Crit Care Med. 2007; 35: S401-S407Crossref PubMed Scopus (39) Google Scholar It can be seen that the evidence for clinical usefulness of perioperative echocardiography is derived from audit data and expert opinion in case series. In audits, authors compare published guidelines with their practice. They then interpret data and make conclusions on the utility of echocardiography. Unfortunately, evidence from case series is largely descriptive and subject to bias from the investigators. The purist would look for more objective evidence from cohort studies and randomized controlled trials. A cohort study evaluating the association between echocardiography and outcome may be possible. As would be the case with any outcome study evaluating a monitoring technique, it would require large numbers of patients over a long period of time. Cohort studies would be subject to selection bias and information bias; there would also be the problem of confounding owing to other factors such as severity of illness. What can we say about randomized controlled trials, perhaps evaluating TOE in high-risk patients having abdominal aneurysm surgery? In theory, this study design would obviate the problem of confounding, provided results are analysed on an intention-to-treat basis. Both arms of the study, that is to say, with and without echocardiography, would have the same confounding factors and thus any difference in outcome between them would be attributable to perioperative echocardiography and enhanced clinical management. While this type of study design would provide the best level of evidence, it would still be subject to much observer and performance bias, as blinding would not be possible. Thus, study designs for assessing the relationship between perioperative echocardiography and outcome have limitations. The benefits of perioperative echocardiography should be weighed against its risks.18Côté G Denault A Transesophageal echocardiography-related complications.Can J Anesth. 2008; 55: 622-647Crossref PubMed Scopus (77) Google Scholar Of the imaging methods, TOE is the most invasive and complications have arisen, albeit infrequently. Data for complications attributable to TOE are derived from cardiac anaesthetic practice. Typical injuries include odynophagia, dental injury, upper gastrointestinal haemorrhage, and oesophageal perforation. In a case series of 4784 patients, six complications were detected, giving an incidence of 0.13%.19Kallmeyer IJ Collard CD Fox JA Body SC Shernan SK The safety of intraoperative transoesphageal echocardiography: a case series of 7200 cardiac surgical patients.Anesth Analg. 2001; 92: 1126-1130Crossref PubMed Scopus (361) Google Scholar This rate is similar to that of 0.2% in another case series examining 7200 patients.20Piercy M McNicol L Dinh DT Story DA Smith JA Major complications related to the use of transesophageal echocardiography in cardiac surgery.J Cardiothorac Vasc Anesth. 2009; 23: 62-65Abstract Full Text Full Text PDF PubMed Scopus (83) Google Scholar A monitor is useful only if the information that it provides is of high quality and interpreted correctly. Perioperative echocardiography is still a specialized form of monitoring in anaesthetic practice. Unlike any other monitors in anaesthesia, for example, pulse oximetry or gas analysis, more training is required before sufficient expertise and consistency can be attained. In cardiac anaesthetic practice, courses, examinations, and accreditation processes have been introduced over the past 15 years to educate and encourage its use.21Swanevelder J Chin D Kneeshaw J et al.Accreditation in transoesphageal echocardiography: statement from the Association of Cardiothoracic Anaesthetists and the British Society of Echocardiography Joint TOE Accreditation Committee.Br J Anaesth. 2003; 91: 469-472Abstract Full Text Full Text PDF PubMed Scopus (23) Google Scholar More recently, these educational initiatives have extended to include non-cardiac practice. There is considerable enthusiasm22Vieillard-Baron A Slama M Cholley B Janvier G Vignon P Echocardiography in the intensive care unit: from evolution to revolution?.Int Care Med. 2008; 34: 243-249Crossref PubMed Scopus (120) Google Scholar and four levels of competencies have been proposed for training in critical care.2Price S Via G Sloth E et al.Echocardiography practice, training and accreditation in the intensive care: document for the World Interactive Network Focused on Critical Ultrasound (WINFOCUS).Cardiovasc Ultrasound. 2008; 6 (doi:10.1186/1476-7120-6-49): 49Crossref PubMed Scopus (174) Google Scholar At the most basic level, an emergency echocardiogram may be obtained to diagnose major causes of arrest or shock, and the operator is capable of recognizing when referral for a second opinion is indicated. The focused scan fits in here and acronyms include FATE (Focused Assessment with Transthoracic Echocardiography) and FEEL (Focused Echocardiographic Evaluation in Life support). The next stage is Level 1 where all standard views should be obtained and there is some ability to diagnose common abnormalities. At Level 2, the sonographer should be able to diagnose all cardiovascular abnormalities but not carry out specialized and research-based echocardiographic examinations that would befit competence at Level 3. Although perioperative echocardiography is well-established in cardiac anaesthesia, it is not so in routine general anaesthetic practice. The main reason for this disparity probably relates to the profound influence it has made on cardiac surgery. For example, retrospective analysis of prospectively collected data from two case series showed that at least 5.6% of cardiac operations were altered on the basis of intraoperative echocardiographic findings and that there were cost-benefit savings.23Fanshawe M Ellis C Habib S Kondstadt SN Reich DL A retrospective analysis of the costs and benefits related to alterations in cardiac surgery from routine intraoperative transesophageal echocardiography.Anesth Analg. 2002; 95: 824-827PubMed Google Scholar, 24Bettex DA Prêtre R Jenni R Schmid ER Cost-effectiveness of routine intraoperative transoesophageal echocardiography in pediatric cardiac surgery: a 10 year experience.Anesth Analg. 2005; 100: 1271-1275Crossref PubMed Scopus (51) Google Scholar These findings concur with more recent data from 12 566 patients in whom TOE influenced surgical decisions (and thus cost effectiveness), particularly during combined valve and graft operations.25Eltzschig HK Rosenberger P Loffler M Fox JA Aranki SF Shernan SK Impact of intraoperative transesophageal echocardiography on surgical decisions in 12,566 patients undergoing cardiac surgery.Ann Thoracic Surg. 2008; 85: 845-852Abstract Full Text Full Text PDF PubMed Scopus (179) Google Scholar For non-cardiac surgery, however, there is no definitive recommendation for perioperative echocardiography. Indeed, the 2007 guidelines of the American College of Cardiology and the American Heart Association maintain that there is insufficient evidence to determine the cost-effectiveness of TOE for its use as a diagnostic monitor or to guide therapy during non-cardiac surgery.26Fleisher LA Beckman JA Brown KA et al.ACC/AHA 2007 Guidelines on perioperative cardiovascular evaluation and care for noncardiac surgery: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines.Circulation. 2007; 116: e418-e500Crossref PubMed Scopus (703) Google Scholar Perioperative outcomes are affected adversely by haemodynamic complications such as myocardial ischaemia, cardiac tamponade, thromboembolism, and hypovolaemia. Official guidelines recommend echocardiography for investigation of such major haemodynamic disturbances.27Cheitlin MD Armstrong WF Aurigemma GP et al.ACC/AHA/ASE 2003 Guideline Update for the Clinical Application of Echocardiography.J Am Soc Echocardiogr. 2003; 16: 1091-1110PubMed Scopus (0) Google Scholar In the peri-arrest situation, proposals have been made recently to include ‘point-of-care’ TTE in Advanced Life Support algorithms.28Breitkreutz R Walcher F Seeger F Focused echocardiographic evaluation in resuscitation management: concept of an advanced life support-conformed algorithm.Crit Care Med. 2007; 35: S150-S161Crossref PubMed Scopus (276) Google Scholar However, as expectations for improved medical care continue to increase in an ageing population,29Dunnell K Ageing and mortality in the UK Office for National Statistics.in: Population Trends. Palgrave Macmillan, New York2008: 6-23http://www.statistics.gov.uk/downloads/theme_population/Population-Trends-134.pdfGoogle Scholar prophylaxis or early detection of haemodynamic complications would be preferable to rescue utilization. To achieve this goal from a monitoring perspective, perioperative echocardiography would have to become more widely utilized in non-cardiac anaesthesia. We suggest that routine perioperative echocardiography in non-cardiac surgery would be indicated in patients who have cardiovascular disease and are expected to require cardiovascular support, such as inotropes or mechanical support. Other indications include: surgery, such as major vascular surgery and lower limb surgery, in which significant haemodynamic changes are anticipated; cardioversion in patients with risk factors for thromboembolism;30Tan CNH Fraser AG Transesophageal echocardiography and cardiovascular sources of embolism: implications for perioperative management.Anesthesiology. 2007; 107: 333-346Crossref PubMed Scopus (18) Google Scholar and during percutaneous cardiological procedures, for example, device closure of a patent foramen ovale. In addition, perioperative echocardiography is indicated when conventional anaesthetic monitoring does not provide the answer to an underlying cardiovascular problem, for example, endocarditis, pericardial effusion, valvular dysfunction, and obstruction of the left ventricular outflow tract. The modality of perioperative echocardiography (TOE or TTE) would depend on factors such as: general anaesthetic state, access to the patient, anticipated image quality, and expertise of the echosonographer. While TOE would be the preferred method in the operating theatre, a combination of TOE and TTE is more likely to be utilized in critical care. In conclusion, over time with improvements in education, miniaturization of transducers, and affordable basic equipment, more anaesthetists will utilize echocardiography. We envisage that there will be increased integration with conventional anaesthetic monitors and that perioperative echocardiography will be the new standard in monitoring as it becomes part of routine non-cardiac anaesthetic practice. Download .zip (.0 MB) Help with zip files Download .zip (.0 MB) Help with zip files
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