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Perioperative Use of Focused Transthoracic Cardiac Ultrasound: A Survey of Current Practice and Opinion

Conlin, Frederick MD*,†; Connelly, Neil R. MD*,†; Eaton, Michael P. MD; Broderick, Patrick J. DO*,†; Friderici, Jennifer MSPH*,§; Adler, Adam C. MS, MD, FAAP

doi: 10.1213/ANE.0000000000002089
Hemostasis: Original Clinical Research Report
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BACKGROUND: The advent of portable ultrasound machines in recent years has led to greater availability of focused cardiac ultrasound (FoCUS) in the perioperative and critical care setting. To our knowledge, its use in the perioperative setting among anesthesiologists remains undefined. We sought to assess the use of FoCUS by members of the Society of Cardiovascular Anesthesiologists (SCA) in clinical practice, to identify variations in its application, to outline limits to its use, and to understand the level of training of physicians using this technology.

METHODS: A 26-question anonymous and voluntary online survey assessing the participants’ training level with FoCUS, frequency of use, and opinions regarding incorporating it into residency training and developing a pathway to basic certification. The survey was distributed to the members of the SCA via email.

RESULTS: The survey was completed by 379 of 3660 members of the SCA (10%). Of the respondents, the majority (67%) had completed a cardiovascular anesthesiology fellowship with 58% identifying their practice as academic, while 37% stated they were in private practice, and 6% were military/Veterans Administration. Most (84%) of the respondents practiced in North America. Eighty-one percent reported familiarity with FoCUS, while 47% stated they use it in their clinical practice. Those practicing in North America were significantly less likely to utilize FoCUS in their practice as compared to other respondents. With regard to training and certification, 88% believe FoCUS education should be integrated into residency training programs and 74% believe there should be a pathway to basic certification for FoCUS.

CONCLUSIONS: While most cardiovascular anesthesiologists are familiar with FoCUS, a minority have integrated it into their practice. Roadblocks such as lack of training, the fear of missing diagnoses, lack of resources, and the lack of a formal certification process must be addressed to allow for more widespread use of perioperative cardiac ultrasound.

Published ahead of print May 19, 2017.

From the *Department of Anesthesiology, Baystate Medical Center, Springfield, Massachusetts

Department of Anesthesiology, University of Massachusetts Medical School-Baystate, Springfield, Massachusetts

Department of Anesthesiology; University of Rochester School of Medicine and Dentistry, Rochester, New York

§Department of Biostatistics and Epidemiology, Baystate Medical Center, Springfield, Massachusetts

Department of Anesthesiology, Perioperative and Pain Medicine, Division of Cardiovascular Anesthesiology, Texas Children’s Hospital, Baylor College of Medicine, Houston, Texas.

Published ahead of print May 19, 2017.

Accepted for publication February 24, 2017.

Funding: None.

The authors declare no conflicts of interest.

Supplemental digital content is available for this article. Direct URL citations appear in the printed text and are provided in the HTML and PDF versions of this article on the journal’s website.

The results presented in this article have been submitted for presentation at the Society for Cardiovascular Anesthesiologists meeting, Orlando, FL, April 2017.

Reprints will not be available from the authors.

Address correspondence to Frederick Conlin, MD, Department of Anesthesiology, Baystate Medical Center, 759 Chestnut St, Springfield, MA 01199. Address e-mail to Frederick.Conlin@baystatehealth.org.

The application of ultrasound has expanded significantly in recent decades and is becoming part of everyday medical practice.1 Bedside focused cardiac ultrasound (FoCUS) provides noninvasive and real-time visualization of cardiac and vascular structures and allows for the serial measurement and monitoring of cardiac function. FoCUS is a protocol for a transthoracic ultrasonographic examination of the cardiovascular system, designed for the noncardiologist.1,2 FoCUS uses limited ultrasound windows to identify major pathologies in specific clinical settings and is not meant to replace a comprehensive formal echocardiogram or cardiology consultation.4

FoCUS has been shown to be useful throughout the perioperative period for assessment and monitoring as well as during critical moments for time-sensitive clinical decision-making.3,4,5 Preoperatively, FoCUS has been used to identify and quantify auscultated cardiac murmurs, elucidate causes of persistent hypotension, and guide resuscitative efforts.6–10 It can also be used during cardiopulmonary resuscitation to identify reversible causes of cardiopulmonary collapse that may be elusive by physical examination alone.5,6,11–18 FoCUS during cardiac arrest may help determine whether continued resuscitative efforts are indicated as patients found to have complete cessation of cardiac activity by ultrasound after initial optimization have a near 100% mortality.19,20

Despite increasing evidence and expert opinion supporting its use and feasibility, the use of FoCUS in the perioperative setting remains undefined.3,21–23 While professional societies for emergency medicine and critical care medicine have made recommendations for FoCUS education and utilization, the American Society of Anesthesiologists and the National Board of Echocardiography have not yet provided a pathway toward certification for transthoracic echocardiography (TTE) similar to that existing for basic transesophageal echocardiography (TEE).24–26 Even with support for expansion of ultrasound education from medical school through residency, there are no formal recommendations for training, evaluation, or certification in focused TTE within the field of anesthesiology, which differs from European training guidelines and training in other specialties such as emergency medicine.27–28

We aimed to identify possible barriers to the adoption of FoCUS by cardiovascular anesthesiologists. We surveyed members of the Society of Cardiovascular Anesthesiologists (SCA) to estimate the frequency with which FoCUS is used in their practice, their level of experience, their opinion regarding residency training and establishing a pathway to basic certification for FoCUS, and to identify modifiable factors hindering its use by anesthesiologists.

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METHODS

IRB approval was obtained from the Human Research Protection Program at Baystate Medical Center. Given the fact that the survey was anonymous and voluntary, the requirement for individual consent was waived as participation in the survey implied consent.

The authors developed an online survey in Research Electronic Data Capture, a web-based application designed to support data collection and management for research studies. An electronic survey was sent to all 3660 members of the SCA via email initially in December 2015 and 2 additional times to improve participation. It remained open for a period of 4 months. The survey consisted of 26 multiple-choice– and fill-in-the-blank–type questions (Supplemental Digital Content, Appendix, http://links.lww.com/AA/B740).

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Data Analysis

Descriptive statistics (means ± standard deviations, medians/interquartile ranges, or proportions as appropriate) were used to characterize the data. Proportions were calculated with exact 95% confidence intervals (CIs). Respondent characteristics were compared between respondents who did and did not report FoCUS use using the Fisher exact test (proportions). Univariable logistic regression was used to estimate the unadjusted odds of FoCUS utilization as a function of selected respondent characteristics, with 95% CIs. All P values shown are 2-sided, with a significance criterion of P < .05. Stata 14.1 (StataCorp LP, College Station, TX) was used for all analyses.

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Sample Size and Power

Before data collection, the authors determined that at least 250 analyzable questionnaires would be needed to achieve 80% power to detect, with a significance criterion of .05, an odds ratio of 2.1, assuming balanced groups and a proportion of 0.53 in the exposed versus 0.35 in the unexposed. This effect size is considered to be small-to-medium in magnitude.

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RESULTS

The survey was sent to 3660 SCA members with 439 participants having completed the survey either in whole or in part. We did receive reports of some surveys incorrectly being identified as junk mail, which was reported to the SCA. Of these, 379 (10.4%) had data sufficient for analysis. Most (361 or 95.2%) of the respondents were attending anesthesiologists, 3.4% were anesthesia fellows, and 1.3% were anesthesia residents. More than half (57.5%) of the respondents worked in academic versus 36.7% in private practice. The majority (83.9%) of survey participants were from North America. A cardiovascular anesthesiology fellowship had been completed by 67.3% (95% CI, 62.4%–71.8%) of respondents.

Among respondents, 81.2% (95% CI, 76.4%–84.4%) reported that they were familiar with FoCUS, 72.8% (95% CI, 68.1%–77.1%) had formal echocardiographic training, and 31.3% had some form of TTE training. Only 46.7% (95% CI, 41.7%–51.8%) reported using FoCUS in their clinical practice, with the majority of these using it at least weekly. Frequency of use by those who stated they utilize FoCUS is listed in Table 1.

Table 1.

Table 1.

The vast majority (88.7% [95% CI, 85.0%–91.5%]) of respondents believe that FoCUS training should be incorporated into anesthesiology residency training, and 74.4% (95% CI, 69.8%–78.6%) believe that there should be a pathway to basic certification, similar to that existing for perioperative TEE. Despite this, only 40% (95% CI, 35.3%–45.1%) reported feeling comfortable teaching FoCUS. The perceived limitations to the use of FoCUS based on survey responses are represented in the Figure.

Figure.

Figure.

Providers in North America were significantly less likely to use FoCUS compared with providers from other geographic regions (proportions: 0.40 vs 0.82; difference in proportions: −0.42, 95% CI, 0.31–0.53). Those in academic practice were significantly more likely to perform FoCUS when compared with those who practice in a private setting (proportions: 0.57 vs 0.27; difference: 0.30, 95% CI, 0.20–0.40). Completion of a fellowship was not associated with FoCUS use in clinical practice (0.48 currently using FoCUS had fellowship training versus 0.44 not currently using FoCUS; difference: 0.05, 95% CI, −0.06 to 0.15), although those who received TTE training in fellowship were more likely to use FoCUS (proportions: 0.87 vs 0.47; difference: 0.40, 95% CI, 0.29–0.52). Those with formal echocardiographic training of any variety are significantly more likely to report using FoCUS in their practice (proportions: 0.53 vs 0.29; difference: 0.24, 95% CI, 0.14–0.35). There was no statistical difference in FoCUS use between respondents who had been practicing for >10 years versus those in practice <10 years (proportions: 0.44 vs 0.52; difference: 0.08, 95% CI, −0.18 to +0.02). Demographics of respondents based on their experience with FoCUS are reported in Table 2.

Table 2.

Table 2.

Institutional credentialing was rare, with 93.7% (95% CI, 90.7%–95.7%) stating no formal process in their practice. When credentialing was present, most (66.7%) reported that it was through their anesthesiology department.

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DISCUSSION

Results from this survey illustrate the relative lack of FoCUS incorporation into anesthesia practice and more importantly identify the perceived limitations to widespread adoption. Despite this, most respondents believe that FoCUS education should be a part of anesthesiology residency training and that a path to basic FoCUS certification should exist.

While other studies have shown that a majority of anesthesia residents desire formal FoCUS training, most US anesthesia residents have not been exposed to a FoCUS educational program and when they have it is often very limited.27 Our survey shows that while most SCA members believe that it should be incorporated into anesthesia residency training, only 46.6% use FoCUS and even fewer (40%) are comfortable teaching FoCUS. Given that lack of training was listed most frequently in the survey responses as a hurdle to the more widespread adoption of FoCUS by anesthesiologists, it would seem that training practices will have to evolve if this technology is going to be consistently and effectively taught to anesthesia residents. We found that respondents who had received training in echocardiography in residency or fellowship were significantly more likely to use FoCUS in their practice than those who had not had this training. However, incorporation of transthoracic ultrasound imaging into anesthesia residency and fellowship curricula is uncommon.

Overall, a minority of responders (46.6%) report integrating FoCUS into their practice, while 19.3% reported being totally unfamiliar with its use. Of the clinicians in our survey who report using FoCUS, most do so fairly frequently. Use of FoCUS at least weekly as reported by 61.4% would suggest that, at least for these physicians, it has value and assists in their decision-making enough to warrant continued use.

We found that FoCUS was used significantly more often by those practicing outside of North America. Outside of the United States, anesthesiologists often have a larger role in critical care, which may partially explain their more frequent use of FoCUS.29 It has been speculated that restricting TEE practice to cardiothoracic anesthesiologists may have hindered the adoption of TTE by anesthesiologists on a broader level by causing unfamiliarity among general anesthesiologists.30 However, we found that, at least among SCA members, completion of a cardiac anesthesia fellowship did not increase the likelihood for FoCUS usage.

Certainly, practice of FoCUS or any ultrasound protocol requires basic competency in image acquisition and interpretation.9 One of the stronger arguments against more widespread adoption of FoCUS highlights the concern that using FoCUS with inadequate training may lead to incorrect or missed diagnoses, a concern among 88.9% and 54.2% of survey respondents, respectively.31 However, numerous studies have demonstrated that even with minimal training, most providers can learn to recognize clinically significant pathology such as ventricular dysfunction and pericardial effusions.16,22,32–40 Training should include a combination of didactic education, hands-on image acquisition (both actual and simulator models), and image interpretation.2,7 Training should commence with ultrasound courses aimed at instruction for novice sonographers in basic ultrasound image and interpretation. A variety of courses are available, which are taught by anesthesiologists, emergency medicine, and/or critical care medicine faculty, that provide a basic foundation for ultrasound image acquisition. From there, providers can learn to identify clinically significant pathologies based on self-review of a vast library or ultrasound resources. See et al41 demonstrated that with this self-teaching approach, providers should be able to interpret significant ultrasound findings reliably. Adequate training in image acquisition and interpretation may allay the fears of an incorrect or missed diagnosis.

While a formal certification process is lacking for the use of TTE in anesthesia, credentialing, and ultrasound education oversight can be achieved through individual institutions with or without oversight from cardiology or radiology. Until anesthesia societies establish their own credentialing process, providers can use other societies’ guidelines and recommendations for noncardiologists to demonstrate competence in bedside ultrasound. One option would be for the American Board of Anesthesiology to collaborate with or model after the recommendations set forth by the American College of Emergency Physicians, which included a guide for echocardiography training in their emergency ultrasound curriculum.25 Similarly, Mayo et al42 report the specific criteria for assessing competency in basic ultrasonography as defined by the American College of Chest Physicians. Alternatively, Conlon et al43 reported their establishment and implementation of a bedside ultrasound program by novice (noncardiology) sonographers in collaboration with the cardiology and radiology departments. Obtaining oversight from local experts and individual institutional credentialing boards until such time that a formal pathway for anesthesiologists is established may help increase the use of FoCUS, factors that 36.5% of survey respondents reported to be a limitation to their incorporation of FoCUS.

Our survey does have limitations, notably the relatively low response rate which may introduce bias. Providers familiar with the use of FoCUS may be inherently more likely to respond to the survey; if this occurred, we may overestimate the true interest and awareness of FoCUS. As in all survey studies, the possibility for reporting bias (nonresponse bias) exists in which SCA members unfamiliar with this modality may be more likely to be nonresponders as opposed to reporting unfamiliarity. Additionally, the survey was only sent to SCA member and therefore may not reflect the use of FoCUS by anesthesiologists as a whole. We make the assumption that if anesthesiologists with either a strong interest in cardiac anesthesia or specialized echocardiography training underutilize FoCUS, the utilization among the broader population would be less.

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CONCLUSIONS

While most cardiovascular anesthesiologists who completed our survey are familiar with FoCUS only about half have integrated its use into their practice. By elucidating the most common limitations to more widespread adoption of FoCUS in anesthesia —lack of training, the fear of missing diagnoses, and the lack of a formal certification process—we can attempt to address these issues. If more perioperative patients are to benefit from the use of bedside diagnostic ultrasound techniques, cardiac ultrasound and FoCUS must be incorporated into the required anesthesia residency curriculum followed by a formal certification process.

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DISCLOSURES

Name: Frederick Conlin, MD.

Contribution: This author helped with study design, data analysis, and manuscript preparation.

Name: Neil R. Connelly, MD.

Contribution: This author helped with study design, data analysis, and manuscript preparation.

Name: Michael P. Eaton, MD.

Contribution: This author helped with study design, data analysis, and manuscript preparation.

Name: Patrick J. Broderick, DO.

Contribution: This author helped with study design, data analysis, and manuscript preparation.

Name: Jennifer Friderici, MSPH.

Contribution: This author helped with study design, data analysis, statistical analysis, and manuscript preparation.

Name: Adam C. Adler, MS, MD, FAAP.

Contribution: This author helped with study design, data analysis, and manuscript preparation.

This manuscript was handled by: Roman M. Sniecinski, MD.

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