Comparison of visual estimation and quantitative measurement of left ventricular ejection fraction in untrained perioperative echocardiographers

BACKGROUND

Perioperative evaluation of the left ventricular systolic function is essential information to help diagnose and manage life-threatening perioperative emergencies. Although quantifying the left ventricular ejection fraction (LVEF) is recommended to determine the left ventricular function, it may not always be feasible in emergency perioperative settings. This study compared the visual estimation of LVEF (eyeballing) by noncardiac anesthesiologists with the quantitative LVEF measured using a modified Simpson's biplane method.

METHODS

Transesophageal echocardiographic (TEE) studies of 35 patients were selected and 3 different echocardiographic views (the mid-esophageal four chamber view, the mid-esophageal two chamber view, and the transgastric mid-papillary short axis view) were recovered from each study and displayed in random order. Two cardiac anesthesiologists certified in perioperative echocardiography independently measured LVEF using the modified Simpson method and categorized LVEF into five grades: hyperdynamic LVEF, normal, mildly reduced LVEF, moderately reduced LVEF and severely reduced LVEF. Seven noncardiac anesthesiologists with limited experience in echocardiography also reviewed the same TEE studies and estimated the LVEF and graded LV function. The precision of the LV function classification and the correlation between visual estimation of LVEF and quantitative LVEF were calculated. The agreement of measurements between the two methods was also assessed.

RESULTS

Pearson's correlation between the LVEF estimated by the participants and the quantitative LVEF using the modified Simpson method was 0.818 (p < 0.001). Of a total of 245 responses, 120 (49.0%) responses were correct grading of the LV function. Participants were able to classify the LV function more accurately in the LV function grades 1 and 5 (65.3%). The 95% level of agreement of the Bland-Altman method was - 11.3-24.5. -21.9-22.6, - 23.1-26.5, - 20.5-22.0 and - 26.6-11.1 for LV grade 1 to 5, respectively.

CONCLUSION

Visual estimation of LVEF in perioperative TEE has acceptable accuracy in untrained echocardiographers and can be used for rescue TEE.

Patterns of Use in Transesophageal Echocardiography for Liver Transplantation: A Systematic Review

Transesophageal echocardiography is frequently but not always used to guide anesthetic management during liver transplantation. We performed a systematic review of the literature to identify and summarize any studies reporting on the frequency and characteristics of TEE use for liver transplantation. Studies were identified by searching several relevant terms on PubMed and citation searching of relevant reviews. We identified 5 studies reporting the results of surveys performed between 2003 and 2018. Use of TEE for liver transplantation increased from 11.3% of centers in 2003 to greater than 90% of centers by 2014 and 2018. Only 38%-56% of centers use it routinely with the rest using it only in special circumstances. About a third of centers usually perform a comprehensive exam, with the majority performing a more limited exam based on the needs of the case. Use of TEE for liver transplantation is common but not universal. This review summarizes the current knowledge about the frequency and circumstances of use, but there is an opportunity for further systematic study and discussion.

Bleeding Complications from Transesophageal Echocardiography for Liver Transplantation: A Systematic Review

Transesophageal echocardiography (TEE) for liver transplant has historically been avoided due to concern it may cause bleeding from esophageal varices. However, several recent studies, as well as increasing clinical experience, have indicated that it may be safe in many circumstances. We performed a systematic review of the literature to identify and summarize studies reporting complications in patients having TEE during liver transplant. Studies were identified by searching relevant key terms on PubMed as well as citation searching in relevant reviews. We identified 6 studies between 1996 and 2015 which evaluated complications of TEE during liver transplant. They reported an overall bleeding complication rate between .3% and 2.8% and a major bleeding complication rate between .0% and .8%. Most of the major bleeds had identifiable high-risk features such as recent variceal bleeding or banding. Review of the literature suggests that TEE may be safely used in patients undergoing liver transplantation, even with known varices, with a complication rate similar to that of all patients undergoing TEE. However, the risks of TEE may outweigh the potential benefits among patients undergoing liver transplant with particular high-risk features.

Pilot Study Suggests Smartphone Application Knowledge Improves Resident Transesophageal Echocardiography Knowledge: A Randomized Controlled Trial

OBJECTIVE

The objective of this study was to determine whether an asynchronous smartphone-based application with image-based questions would improve anesthesiology resident transesophageal echocardiography (TEE) knowledge compared with standard intraoperative teaching alone.

DESIGN

Prospective, single-blinded, pilot, randomized controlled trial.

SETTING

Large university teaching hospital.

PARTICIPANTS

Participants were anesthesiology residents on their cardiac anesthesiology rotation.

INTERVENTIONS

EchoEducator, a TEE image-based smartphone application of learning content through questions, was developed. Content was derived from the Examination of Special Competence in Basic Perioperative Transesophageal Echocardiography and the Objective Structured Clinical Examination portion of the APPLIED Examination and focused on identification of basic TEE views, cardiac structures, and pathology. Residents were randomly assigned to receive access to either the application or to standard intraoperative teaching. Thirty residents met inclusion criteria, and 18 residents completed the study. A pre-intervention assessment was given at the beginning of the rotation, and a post-intervention assessment was given after 2 weeks.

MEASUREMENTS

The primary outcome was the difference between the post-test score and the pre-test score. Standard bivariate statistics and the chi-square test were used for categorical variables, and the Student t test was used for continuous variables. Tests were 2-sided, and statistical significance was set at p < 0.05. The intervention group demonstrated a greater increase in score; (+19.19% [95% confidence interval 4.14%-34.24%]; p = 0.02) compared with the control group.

CONCLUSIONS

This study supports the hypothesis that use of a smartphone-based asynchronous educational application improves TEE knowledge compared with traditional modalities alone. This supports an opportunity to improve medical education by expanding the role of web-based asynchronous learning.