[Contribution of transesophageal echocardiography in intensive care: a prospective assessment]

Transesophageal echocardiography and noncardiac surgery

The use of transesophageal echocardiography (TEE) for monitoring during cardiac and noncardiac surgery has increased exponentially over the past few decades. TEE has evolved from a diagnostic tool to a monitoring device and a procedural adjunct. The close proximity of the TEE transducer to the heart generates high-quality images of the intracardiac structures and their spatial orientation. The use of TEE in noncardiac and critical care settings is not well studied, and the evidence of the benefits of its use in these settings is lacking. Despite the widespread availability of TEE equipment in US hospitals, less than 30% of anesthesiologists are formally trained in the use of perioperative TEE. In this review, the safety and indications of TEE are reviewed and detailed analysis of the best available evidence in this regard is presented. Landmark trials evaluating the use of TEE and its therapeutic impact in noncardiac surgical setting are critically reviewed. This article details recommendations to familiarize anesthesiologists with TEE technology to exploit it to its fullest potential to achieve better patient monitoring standards and eventually improve outcome. Training of greater numbers of anesthesiologists in TEE is needed to increase awareness of the indications and contraindications. Until relatively inexpensive TEE equipment is available, the initial cost of equipment acquisition remains a significant prohibitive factor limiting its widespread use.

Importance of transesophageal echocardiography in the critically ill and injured patient

Echocardiography, particularly transesophageal echocardiography (TEE), is a vital diagnostic and monitoring imaging modality for the intensivist. The field of echocardiography spans different venues and pathologies, ranging from surface transthoracic echocardiography and portable hand-held echocardiography, to contrast echocardiography, stress echocardiography, and TEE, among others. Numerous investigations have proven the worth of echocardiography, especially TEE, in the critically ill and injured patient, changing lives with the identification of obvious and subtle cardiothoracic diseases. Because this powerful imaging tool is immediately available and portable, crucial delays in diagnosis are not commonplace; rather than echocardiography, TEE, specifically, should be (and is in some institutions) the standard of care and management in assisting the intensivist in diagnosis of a variety of maladies. The effect of TEE technology is quite formidable, and numerous investigations have borne this out. The therapeutic effect of TEE ranges from 10% to 69%, with the majority of investigations falling into the 60% to 65% range. The diagnostic yield of TEE is far greater, approaching 78%. This article will detail the importance of echocardiography, its efficacy, and its high-yield imaging capability, particularly when compared with other imaging modalities, even transthoracic echocardiography.

The use and safety of transoesophageal echocardiography in the general ICU -- a minireview

BACKGROUND

The efficacy of transoesophageal echocardiography (TEE) has been evaluated predominantly in medical and cardiac surgical ICUs. This article reviews the pertinent literature and evaluates the impact of TEE in a general surgical ICU.

METHODS

Twenty studies on TEE in the ICU were evaluated for complications, indications, diagnostic, therapeutic, and surgical impact on patient management. Diagnostic impact was defined as identification of the underlying cardiovascular pathology, therapeutic impact as changes in patient management and surgical impact as indication for operative procedures. In addition, we reviewed the TEE reports and patient charts of 216 critically ill patients in a 16-bed multidisciplinary surgical ICU at our university hospital, who underwent a TEE for differential diagnosis of hemodynamic instability from July 1995 to December 1998 to assess the impact of TEE on patient management in a general surgical ICU.

RESULTS

The diagnostic, therapeutic and surgical impact in a total of 2,508 patients ranged from 44 to 99% (weighted mean 67.2%), 10-69% (36.0%), and 2-29% (14.1%), respectively. The complication rate was 2.6%, with no examination related mortality. In our series in a general surgical ICU, a diagnostic, therapeutic and surgical impact was inferred in 191 (88.4%), 148 (68.5%) and 12 (5.6%) patients, respectively. Adverse effects were observed in 5.6%.

CONCLUSION

TEE is safe, well-tolerated and useful in the management of critically ill patients. This applies as well for hemodynamically unstable patients in a general surgical ICU.

The hemodynamically unstable patient in the intensive care unit: hemodynamic vs. transesophageal echocardiographic monitoring

OBJECTIVE

Transesophageal echocardiography is a diagnostic and monitoring modality. The objectives of our study were to compare the diagnoses obtained with continuous transesophageal echocardiography and hemodynamic monitoring in the intensive care unit, to determine interobserver variability of diagnosis obtained with both modalities, and to evaluate its impact.

DESIGN

Prospective cohort study.

SETTING

Surgical intensive care unit.

PATIENTS

Consecutive hemodynamically unstable patients after cardiac surgery.

INTERVENTIONS

At admission, unstable patients were monitored during 4 hrs with transesophageal echocardiography and standard hemodynamic monitoring. The critical care physician evaluated the patients based on all information except the transesophageal echocardiography at 0, 2, and 4 hrs and formulated a hypothesis on the most likely cause of hemodynamic instability. Transesophageal echocardiography information was provided after each evaluation. To evaluate interobserver variability, all the hemodynamic and echocardiographic information was gathered, randomized, and evaluated by five clinicians for the hemodynamic data and five echocardiographers for the transesophageal echocardiography data. The evaluators were blinded to all other information. Kappa statistics were used to evaluate agreement. Impact of transesophageal echocardiography was assessed retrospectively by using the Deutsch scale.

RESULTS

Twenty patients qualified for the study. The agreement between the hemodynamic and echocardiographic diagnosis showed a kappa at admission, 2 hrs, and 4 hrs of 0.33, 0.47, and 0.28. The interobserver agreement for the initial diagnosis (p =.014) and between all evaluators (p <.001) was significantly higher in the echocardiographic compared with the hemodynamic group. The transesophageal echocardiographic information was considered retrospectively to be essential in 34% and valuable in 34% of cases.

CONCLUSIONS

These observations support the belief that transesophageal echocardiographic monitoring in the intensive care unit is associated with higher interobserver agreement in diagnosing and excluding significant causes of hemodynamic instability for postoperative cardiac surgical patients.

Perioperative use of transesophageal echocardiography by anesthesiologists: impact in noncardiac surgery and in the intensive care unit

BACKGROUND

The American Society of Anesthesiologists (ASA) has published practice guidelines for the use of perioperative transesophageal echocardiography (TEE) but the role and impact of TEE performed by anesthesiologists outside the cardiac operating room (OR) is still poorly explored. We report our experience in the use of TEE in the noncardiac OR, the recovery room and in the intensive care unit (ICU) in a university hospital, and analyze the impact of TEE on clinical decision making.

METHODS

Two hundred fourteen patients were included and TEE indications were classified prospectively according to the ASA guidelines. The examinations and data sheets were reviewed by two anesthesiologists with advanced training in TEE. For each examination, it was noted if TEE altered the management according to five groups: 1) changing medical therapy; 2) changing surgical therapy; 3) confirmation of a diagnosis; 4) positioning of an intravascular device; and 5) TEE used as a substitute to a pulmonary artery catheter.

RESULTS

Eighty-nine (37%), 67 (31%) and 58 (27%) patients had category I, II and III indications. The impact was more significant in category I where TEE altered therapy 60% of the time compared with 31% and 21% for categories II and III (P < 0.001). The most frequent reason for changing management was a modification in medical therapy in 53 instances (45%).

CONCLUSION

Our results confirm a greater impact of TEE performed by anesthesiologists on clinical management for category I compared to category II and III indications in the noncardiac OR surgical setting and in the ICU.

Indications and impact of postoperative transesophageal echocardiography in cardiac surgical patients

OBJECTIVE

Transesophageal echocardiography (TEE) has gained widespread acceptance among intensivists as a tool to facilitate decision-making in the management of critically ill patients. This observational study analyzes the indications and impact of TEE and the outcome in patients following cardiac surgery.

DESIGN

Standardized reports containing indication, main diagnosis, and impact on patient management were completed during TEE.

SETTING

Intensive care unit in a university hospital.

PATIENTS

Postoperative cardiac surgery patients requiring TEE.

INTERVENTION

TEE in sedated and mechanically ventilated patients.

MEASUREMENTS AND RESULTS

Reports were obtained in 301 adult patients between June 1996 and June 2000. Indications were postoperative control of left ventricular function in 102 (34%) cases; unexplained, sudden hemodynamic deterioration in 89 (29%); suspicion of pericardial tamponade in 41 (14%); cardiac ischemia in 26 (9%); and "other" in 43 (14%). In 136 patients (45%), a new diagnosis was established or an important pathology was excluded. Pericardial tamponade was diagnosed in 34 cases (11%) and excluded in 36 cases (12%). Other diagnoses included severe left ventricular failure, large pleural effusion, and others. Therapeutic impact was found in 220 cases (73%): change of pharmacologic treatment and/or fluid therapy in 118 cases (40%), resternotomy in 43 (14%), no reoperation necessary in 39 (13%), and various in 20 (7%). No impact was found in 81 cases (27%). In a subgroup of patients in whom preoperative risk scores were evaluated, the indication for a postoperative TEE was significantly associated with a prolonged stay in the intensive care unit: 7 (5.6, 8.4) days vs. 1 (0.8, 1.2) day (median, [95% confidence interval]) (p <.0001), more neurologic complications (18/137 = 13.1% vs. 21/680 = 3.0%) (p <.0001), and increased mortality (34/153 = 22.2% vs. 18/709 = 2.5%) (p <.0001). Corrected for preoperative risk scores, these differences were still significant.

CONCLUSION

Although TEE provided important findings and therapeutic impact in postoperative cardiac surgical patients, patients with comparable preoperative risk who had postoperative TEE examinations had a significantly worse outcome than those without the need for postoperative TEE.

Diagnostic and therapeutic implications of transesophageal echocardiography in medical ICU patients with unexplained shock, hypoxemia, or suspected endocarditis

OBJECTIVE

To evaluate the diagnostic and therapeutic implications of transesophageal echocardiography (TEE) in intensive care patients.

DESIGN

Comparative study.

SETTING

A 10-bed general intensive care unit.

PATIENTS

Between 1 January 1992 and 31 May 1993, 61 patients prospectively identified with shock (n = 14), severe, unexplained hypoxemia (Partial pressure of oxygen in arterial blood/fractional inspired oxygen < 200) (n = 31), or suspected endocarditis (n = 16) underwent a TEE examination to supplement transthoracic echocardiography (TTE) examination.

INTERVENTIONS

The results of each TEE examination were compared with the clinical findings and TTE data. TEE examinations were classified as follows: 0, TEE results were similar to TTE results; 00, TEE examination resulted in exclusion of suspected abnormalities; 1, TEE revealed a new but minor diagnosis compared to the TTE diagnosis; 2, TEE revealed a new major diagnosis not requiring a change of treatment; 3, TEE results revealed a new major diagnosis requiring an immediate change of treatment.

RESULTS

Intraobserver reliability of the TEE classification was confirmed by a 100% concordance and interobserver reliability was evaluated as an 84% concordance. Results of the TEE classification were: class 0, n = 21 (34%); class 00, n = 13 (21%); class 1, n = 7 (12%); class 2, n = 8 (13%); class 3, n = 12 (20%). Therapeutic implications of TEE in class 3 patients were cardiac surgery in 5 patients (2 cases of acute mitral regurgitation, 2 valvular abscesses, and 1 hematoma compressing the left atrium), discontinuation of positive end-expiratory pressure in 1 ventilated patient with an atrial septal defect, weaning off mechanical ventilation in 1 patient with an atrial septal defect, prescription of antimicrobial therapy in 3 patients with endocarditis, and prescription of anticoagulant therapy in 2 patients with left atrial thrombus. No difficulty inserting the transducer was observed in any of the 61 patients studied. The only noteworthy complication was a case of spontaneously resolving atrial fibrillation.

CONCLUSION

TEE is safe and well tolerated and is useful in the management of patients in the intensive care unit with shock, unexplained and severe hypoxemia, or suspected endocarditis when TTE is inconclusive.

[Esophageal perforation after transesophageal echocardiography]

Transoesophageal echocardiography (TOE) is increasingly used in cardiology, cardiac surgery and intensive care. Its complications are rare. We report a case of perforation of the oesophagus after TOE in a 71-year-old woman, scheduled for an elective aortic valve replacement. Her medical history included arterial hypertension but no pre-existing oesophageal disease. A Hewlett Packard ultrasound imaging system was used, with a 5 MHz single plane probe. After local anaesthesia, the transducer probe was inserted into the distal oesophagus, after three attempts, without any apparent incident. A few hours later, the patient complained of acute cervical and dorsal pain. Examination showed severe skin emphysema in of neck, but neither breathing difficulties, nor haemodynamic modifications. The EKG was normal and body temperature at 38.8 degrees C. The opacification of the oesophagus showed a passage of the contrast medium into the mediastinum. Emergency surgical exploration by left cervicotomy showed a perforation of 2 to 3 cm of the posterior wall of oesophagus, treated with terminal oesophagostomy and drainage. The pressure by the TOE probe on the oesophagus may explain this perforation. The outcome was uneventful. Although TOE is a semi-invasive technique with a low risks its benefit/risk ratio should be considered in each patients before using it.