Anesth Analg 2002;94:1065-1071
© 2002 International Anesthesia Research Society
CARDIOVASCULAR ANESTHESIA
The Use of and Preferences for the Transesophageal Echocardiogram and Pulmonary Artery Catheter Among Cardiovascular Anesthesiologists
Michael J. Jacka, MD FRCPC, MSc*
,
Marsha M. Cohen, MD FRCPC, MSc
||,
Teresa To, PhD¶#,
J. Hugh Devitt, MD FRCPC, MSc||, and
Robert Byrick, MD FRCPC
*Departments of Anesthesiology and Critical Care, University of Alberta, Edmonton, Alberta, Canada; The Clinical Epidemiology & Health Care Research Program, the Department of Anesthesia, The Centre for Research in Women’s Health and the Department of Health Policy, Management, and Evaluation, the ||Department of Anesthesia, Sunnybrook and Women’s College Health Sciences Centre, and the ¶Department of Public Health Sciences, University of Toronto, Toronto, Ontario, Canada; and #Division of Population Health Sciences, Hospital for Sick Children Research Institute, Toronto, Ontario, Canada
Address correspondence and reprint requests to Michael Jacka, MD, FRCPC, MSc, Department of Anesthesia and Critical Care, 3B2.32 Walter C. Mackenzie Health Sciences Centre, Edmonton, AB, T6G 2B7. Address e-mail to mjacka{at}ualberta.ca
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Abstract
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The pulmonary artery catheter (PAC), although widely used in anesthesia for cardiac and vascular surgery, remains controversial. Use of transesophageal echocardiography (TEE) by cardiovascular anesthesiologists may be a substitute or a preference compared with the PAC, but this has been incompletely investigated. An anonymous, cross-sectional survey was mailed to anesthesiologists in Canada and the United States. Anesthesiologists described their use of the PAC and TEE during cardiac and vascular surgery, along with their demographic characteristics. Two hundred sixty-five (77%) of 345 anesthesiologists responded. All had the PAC available for use, and 56% had TEE available. Only 23 (11% overall) reported having undergone echocardiography training, half of whom had completed fellowships. Both the PAC and TEE were more often used in cardiac valvular surgery (P = 0.0001) than in aortocoronary bypass or abdominal vascular surgery. Among all anesthesiologists, the PAC remained the preferred monitor in either cardiac or vascular surgery (P = 0.0001), although many indicated a preference for neither monitor. Among anesthesiologists with echocardiography training, TEE was preferred (P = 0.0004). We found that TEE was accessible to more than half of the surveyed anesthesiologists in cardiovascular surgery, but relatively few of them had completed formal training in its use. Only those with completed formal TEE training indicated a significant preference for TEE use and also used it frequently. Given the continuing controversy about the appropriate application of the PAC, concern about the appropriate application of TEE is prudent. The PAC remains the more frequently used and preferred monitor among cardiovascular anesthesiologists.
IMPLICATIONS: A survey of anesthesiologists found that pulmonary artery catheter monitoring is currently more frequently used compared with transesophageal echocardiography during cardiac and vascular surgery.
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Introduction
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The pulmonary artery catheter (PAC) was introduced to clinical practice three decades ago (1) and is often used by physicians in anesthesiology and critical care. Its potential applications are multiple (2–6) and generally involve obtaining more information about cardiovascular physiology than can be obtained less invasively (1), but also simply and expeditiously.
Transesophageal echocardiography (TEE) was developed to enhance assessment of the structure and function of the heart by cardiologists. Investigations have shown that description of cardiovascular physiology with TEE is significantly closer to "gold standard" assessment than estimates derived with the PAC (7–9). Although the enhanced accuracy and precision of these measurements have not been shown systematically to affect morbidity or mortality, there is anecdotal support (7–9). Optimal use of TEE requires a higher degree of training and maintenance of competence than does use of the PAC (10). Nonetheless, demand for the ability to use TEE as a diagnostic and monitoring technology has been increasing in cardiac anesthesiology (11). It has been suggested by some, for instance, that certification in TEE interpretation and continuing demonstration of competence may become a standard of practice in cardiac anesthesiology (11).
The current availability of TEE among cardiac and vascular anesthesiologists is unknown, as are the number of anesthesiologists with TEE training and the number who actually use the device. The preferences of anesthesiologists for the PAC and TEE in cardiac and vascular anesthetic practice are likewise unknown.
We conducted a survey of a sample of anesthesiologists in Canada and the United States to assess their use of TEE and PAC, their preference for these two modalities, and whether availability of TEE corresponded with preference for its use.
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Methods
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After we received institutional ethics approval, a census of all anesthesiologists from English-speaking hospitals in the Canadian provinces of Ontario, Quebec, New Brunswick, Nova Scotia, Prince Edward Island, and Newfoundland was undertaken. Anesthesiologists from Alberta also participated because of known differences in remuneration structures. All anesthesiologists from randomly selected academic centers in the United States also participated because of estimated differences in the availability and use of TEE compared with Canadian centers. Respondents participated if they delivered at least one anesthetic for a cardiac or vascular procedure in a usual month.
The survey instrument was mailed on January 13, 1998. A second mailing was sent to nonrespondents on February 13, 1998. Those not responding by March 13, 1998, were given a follow-up telephone call to encourage a response and were sent another mailing, if requested. A second and final telephone call was made in the later part of April 1998 for persistent nonresponders. Responses were entered into a database with EpiInfo® (Centers for Disease Control, Atlanta, GA) and analyzed with SAS® version 6.0 (SAS Institute, Cary, NC).
The responses to each of the survey questions were grouped and analyzed. Simple descriptive statistics were used to describe the availability of TEE among cardiac and vascular anesthesiologists, the proportion of respondents using TEE, the proportion of respondents trained to use TEE, the proportion of responding anesthesiologists with training in cardiac anesthesiology, the type of surgery in which TEE and PAC were used, and the preferences of anesthesiologists for the PAC or TEE. Differences between the responses of those who had TEE available or not and who gave anesthetics primarily for cardiac or vascular surgery were assessed with the 
2 statistic or Student’s t-test (P < 0.05). The correlation between the preference for TEE or PAC and the use of TEE or PAC was determined with the rho statistic (P < 0.05).
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Results
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Three-hundred-forty-seven anesthesiologists at 29 centers were surveyed. Two had moved before the mailing and were deleted from the final sample. The overall response rate was 76.8% (265 of 345). Of these 265, 214 (80.8%) described themselves as delivering at least one anesthetic in the average month for a cardiac or abdominal vascular surgical case, and they therefore completed the survey. Subsequent results are based on these 214 respondents.
Of the 214 respondents (Table 1), 119 (56%) reported that TEE was available in the operating room, whereas it was not available to the remaining 95 (44%). The PAC was available to all respondents. Significantly more cardiac cases were performed (P < 0.0001), and more PACs were inserted (P < 0.0001), by anesthesiologists who had TEE available for use (Table 1). Both of these findings persisted as significant when cardiac and vascular anesthesiologists were considered separately (Tables 2, 3). Among vascular anesthesiologists, the availability of TEE was associated with a significantly increased frequency of vascular procedures (Table 3; P < 0.005).
In comparing anesthesiologists from Eastern Canada, Western Canada, and the United States (Table 4), no significant differences in age, sex, duration in practice, or practice type were seen. Significantly more anesthesiologists from Canada had received training in both Canada and the United States (P < 0.0001). Respondents from the United States were more likely to give anesthetics for cardiac surgery than respondents from Canada (P < 0.0004).
Of the respondents (Table 5), 28 (13%) were practicing in the United States, and 186 (87%) were practicing in Canada. The TEE was significantly more frequently available in cardiac than in vascular cases (P = 0.002 and P = 0.08, respectively) among US respondents. Most respondents (43%) were 40–49 yr old, but age was not significantly associated with availability of TEE. Academic, community, and mixed-practice anesthesiologists had similar availability of TEE during cardiac practice, although TEE was significantly more frequently available to academic anesthesiologists during vascular surgery (P = 0.005). Thirteen anesthesiologists (6%) reported having completed a formal echocardiography fellowship, 10 (5%) had taken an echocardiogram course, and the remaining 191 (89%) had no echocardiography training. Forty-five anesthesiologists (21%) reported having completed training in cardiac anesthesiology. Anesthesiologists with cardiac anesthesiology training were much more likely to have completed echocardiography training than others (2 = 19.7; P = 0.001). Of those to whom TEE was available, 98 (82%) of 119 indicated that they had no specific training in its use.
Cardiac anesthesiologists with access to TEE were significantly less likely to use the PAC during aortocoronary bypass grafting (78%) or cardiac valvular surgery (86%) than those without access to TEE (93% and 97%, respectively; P = 0.001; Table 6). This was not observed among vascular anesthesiologists performing cardiac anesthesiology, although their numbers were small (Table 7). Nonetheless, among cardiac anesthesiologists with access to TEE (Table 8), the PAC was significantly more frequently used in both cardiac and vascular cases than was TEE (P < 0.0001). Use of the PAC in abdominal aortic aneurysm repair and aortobifemoral bypass grafting was significantly less frequent than in cardiac procedures, but it was similar whether or not TEE was available and whether the anesthesiologist primarily treated cardiac or vascular cases (Tables 6, 7).
Respondents were asked their preference for the PAC, TEE, both devices concurrently, or neither. The PAC was preferred by the majority of cardiac anesthesiologists during cardiac and vascular surgery, as compared with TEE (Tables 9, 10), regardless of the availability of TEE. This preference was also indicated by vascular anesthesiologists, although less strongly. However, although a small number (9%) of anesthesiologists indicated a preference for both monitors concurrently, nearly one third (29%) of all anesthesiologists indicated that neither the PAC nor TEE was preferred.
When anesthesiologists with echocardiography training were considered (Table 11), they had a greater preference for TEE (45%) than the PAC (18%; P = 0.00004), but they also often indicated a preference for neither monitor. Anesthesiologists with cardiac anesthesiology training also preferred TEE more often than the rest of the group (23% vs 13%; P = 0.04), although less often than their stated preference for the PAC (36%) or neither monitor (39%).
In comparing the preferences for the PAC and TEE with the reported use of either device, the preference for both devices was less than the reported use. Even with availability of TEE, the PAC remained used and preferred by more than twice as many respondents as TEE. The correlations between preference for the PAC, TEE, both monitors, and neither monitor with reported use of these devices are listed in Table 12. Significant correlations were observed between preference and use for both the PAC and TEE (Pearson’s rho = 0.47 and 0.50 for the PAC in cardiac and vascular surgery, respectively, P = 0.0001 in each; and Pearson’s rho = 0.64 and 0.39 for TEE in cardiac and vascular surgery, P = 0.0001 in each). A strong negative correlation between PAC use and reported preference for neither device was also noted (Pearson’s rho = -0.52; P = 0.0001), and this was not seen with TEE preference or use. These findings were similar between cardiac and vascular surgery.
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Discussion
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This survey of practicing cardiovascular anesthesiologists achieved a high response rate (77%). All respondents had the PAC available, but the frequency of PAC use ranged widely. The TEE was available to more than half of the respondents (56%, in 14 centers). Despite the availability of TEE, very few anesthesiologists (i.e., 23, or 11% in total) reported any formal training in echocardiography, of whom only 13 reported having completed fellowship training in the use of TEE. Sixty-five percent of anesthesiologists with TEE available reported using it during cardiac valvular surgery in a representative month, and 34 (29%) used it in more than half of cardiac valvular cases.
Although the "importance" of TEE in these cases is unknown, it is likely that its use produces information that may change medical management. This raises concerns about knowledge base and cost. Regarding TEE knowledge base, although this study was not designed to measure this directly, it was noted that the majority of TEE users, in this study and others (12), had no formal training in its use. TEE use by anesthesiologists not trained in echocardiography has been associated with increased surgical morbidity (12). Furthermore, concerns about user knowledge base have persisted for years regarding the PAC, which is more often used than TEE. These concerns were first raised nearly a decade ago and were widely prevalent (13–15). Another recent study has demonstrated that these knowledge base problems with the PAC persist (16). Despite the lack of consistent objective benefit of the PAC (5,6,17) and reservations about the knowledge base of users (13–15), minimal effort was made to address these concerns until they became public in the lay press (18) and motivated professional organizations to address them.
Regarding cost, it is clear from the frequency of use of the PAC and TEE that these technologies are being used simultaneously or consecutively by some users; this makes TEE an "added" technology. Although TEE may be investigational in some centers, with expected duplication of use of the PAC and TEE, continuation of this pattern would lead to a substantial increase in cost. Early attention to clarify the specific role of TEE is important to minimize increased expenses or adverse events (10,19).
Use of TEE is most common in centers that perform cardiac surgery. Whether this will motivate the adoption of TEE as a standard monitor in cardiac anesthesiology remains to be seen. Ideally, monitoring standards should incorporate assessment of the "value-added" of the introduction and maintenance of a technology (10,19), rather than simple adoption of the practice of large-volume centers.
Along with the educational concerns about TEE use, as with the PAC, is the issue of maintenance of competence. Information from TEE is more complex to interpret than that from the PAC. This may be paradoxically fortunate, because coupled with the much greater acquisition cost of TEE, the opportunity cost of achieving and maintaining competence with TEE may be the most important factor inhibiting widespread diffusion of TEE. The importance of cost issues may have superseded a more important concern, which is the need of objective outcome data demonstrating improvement in patient status. Rather than exclusively accelerating development of educational programs to improve TEE knowledge, it would be equally reasonable to encourage that further diffusion of TEE adhere to the guidelines for training and use that have been developed (10,19), concurrent with evaluation of the effect of TEE on patient outcome. The appropriate measure of benefit could be obtained from a randomized trial focused on morbidity, mortality, and comprehensive costs.
Of interest in this study was that, despite the prevalence and use of the PAC and TEE, the stated preference of the majority of respondents was only slightly in favor of the PAC. Among anesthesiologists with echocardiography training, and somewhat among those with cardiac anesthesiology training, TEE was the preferred monitor. However, nearly one third of all respondents indicated that neither monitor was preferred, suggesting that these devices might be inadequate, unnecessary, or suboptimally used.
The analyses of the factors associated with the use of either the PAC or TEE in cardiac and vascular procedures found the recurring observations that anesthesiologists with echocardiography training were more likely to use TEE in any surgery considered. This may reflect referral from their colleagues of patients who they believe may benefit from TEE.
This study has a few limitations. First, although the response rate was very high, generalization of the observations to the nonresponding 23% may not be appropriate. Although a comprehensive census of Eastern Canadian anesthesiologists was taken, the American centers were from a random sample of academic institutions. Because we found no systematic differences in age, sex, duration in practice, practice type, or amount or type of postcertification training between Eastern Canadian and other centers, it is likely that our results are applicable elsewhere. Nonetheless, the reader is cautioned that there may be other differences across anesthesiologists that may limit the generalizability of this study.
In summary, this study has demonstrated that the PAC is widely applied in anesthesiology for cardiac and vascular surgery and that TEE is also often used, especially in cardiac valvular surgery. Rather than simply replacing the PAC, TEE may currently be an "added" technology. Although its use is greater among anesthesiologists trained in echocardiography and in cardiac anesthesia, only a small number of anesthesiologists have completed formal training in echocardiography; this number is much smaller than the number of anesthesiologists reporting use of TEE. This raises concerns about the quality and application of data derived by TEE users who are not formally trained. Similar concerns about the quality and application of data derived from the PAC, which remains the preferred monitor in cardiovascular anesthesia, have yet to be completely answered. Further diffusion of TEE should be accompanied by continuing evaluation of appropriateness, to avoid the delayed recognition of the concerns still seen with the PAC.
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Acknowledgments
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Dr. Cohen is the recipient of a Senior Scientist Award from the Medical Research Council of Canada. The authors would like to thank the participating anesthesiologists in the survey. The financial support of Abbott Pharmaceuticals, Inc., is gratefully acknowledged.
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References
|
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-
Swan HJC, Ganz W, Forrester JS, et al. Catheterization of the heart in man with the use of a flow-directed balloon-tipped catheter. N Engl J Med 1970; 283: 447–51.
-
Sanchez R, Wee M. Perioperative myocardial ischemia: early diagnosis using the pulmonary artery catheter. J Cardiothorac Vasc Anesth 1991; 5: 604–7.[Medline]
-
Kaplan JA, Wells PH. Early diagnosis of myocardial ischemia using the pulmonary artery catheter. Anesth Analg 1981; 60: 789–93.[Abstract/Free Full Text]
-
Cooper AB, Doig GS, Sibbald WJ. Pulmonary artery catheters in the critically ill. Crit Care Clin 1996; 12: 777–94.[ISI][Medline]
-
Shoemaker WC. The efficacy of central venous and pulmonary artery catheterization and therapy based on them in reducing mortality and morbidity. Arch Surg 1990; 125: 1332–8.[Abstract]
-
Shoemaker WC, Appel PL, Kran HB, et al. Prospective trial of supranormal values of survivors as therapeutic goals in high-risk surgical patients. Chest 1988; 94: 1176–86.[Abstract/Free Full Text]
-
DiCorte CJ, Latham P, Greilich PE, et al. Esophageal Doppler monitor determinations of cardiac output and preload during cardiac operations. Ann Thorac Surg 2000; 69: 1782–6.[Abstract/Free Full Text]
-
Tousignant CP, Walsh F, Mazer CD. The use of the TEE for preload assessment in critically ill patients. Anesth Analg 2000; 90: 351–5.[Abstract/Free Full Text]
-
Fontes ML, Bellows W, Ngo L, et al. Assessment of ventricular function in critically ill patients: limitations of pulmonary artery catheterization. J Cardiothorac Vasc Anesth 1999; 13: 521–7.[ISI][Medline]
-
Shanewise JS, Cheung AT, Aronson S, et al. ASA/SCA guidelines for performing a comprehensive multiplane transesophageal echocardiography examination. Anesth Analg 1999; 89: 870–84.[Free Full Text]
-
Andel H, Huemer G, Wolrab C, et al. Transesophageal echocardiography in anesthesia and intensive care. Acta Anaesthesiol Scand Suppl 1997; 111: 267–9.[Medline]
-
Stevenson JG. Adherence to physician training guidelines for pediatric transesophageal echocardiography affects the outcome of patients undergoing repair of congenital cardiac defects. J Am Soc Echocardiogr 1999; 12: 165–72.[ISI][Medline]
-
Iberti TJ, Fischer EP, Leibowitz AB, et al. A multicentre study of physicians’ knowledge of the pulmonary artery catheter. JAMA 1990; 264: 2928–32.[Abstract]
-
Gnaegi A, Feihl F, Perret C. Intensive care physicians’ insufficient knowledge of right-heart catheterization at the bedside. Crit Care Med 1997; 25: 213–20.[ISI][Medline]
-
Clinical competence in hemodynamic monitoring: a statement for physicians from the ACP/ACC/AHA Task Force on Clinical Privileges in Cardiology. J Am Coll Cardiol 1990; 15: 1460–4.[ISI][Medline]
-
Jacka M, Cohen MM, To T, et al. PAOP estimation: how confident are anesthesiologists? Crit Care Med. In press.
-
Hayes MA, Timmins AC, Yau EH, et al. Elevation of systemic oxygen delivery in the treatment of critically ill patients. N Engl J Med 1994; 330: 1717–22.[Abstract/Free Full Text]
-
Conners AF Jr, Speroff T, Dawson NV, et al. The effectiveness of right heart catheterization in the initial care of critically ill patients. JAMA 1996; 276: 889–97.[Abstract]
-
Hall RI. Do we all need to have TEE capability? Can J Anaesth 1996; 43: 201–5.[Free Full Text]
Accepted for publication December 27, 2001.
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Abstract
Introduction
