Importance of transesophageal echocardiography in the critically ill and injured patient

Feasibility, utility, and safety of fully incorporating transesophageal echocardiography into emergency medicine practice

INTRODUCTION

Transthoracic echocardiography (TTE) is a standard procedure for emergency physicians (EPs). Transesophageal echocardiography (TEE) is known to have great utility in patients who are critically ill or in cardiac arrest and has been used by some EPs with specialized ultrasound (US) training, but it is generally considered outside the reach of the majority of EPs. We surmised that all of our EPs could learn to perform focused TEE (F-TEE), so we trained and credentialed all of the physicians in our group.

METHODS

We trained 52 EPs to perform and interpret F-TEEs using a 4-h simulator-based course. We kept a database of all F-TEE examinations for quality assurance and continuous quality feedback. Data are reported using descriptive statistics.

RESULTS

Emergency physicians attempted 557 total F-TEE examinations (median = 10, interquartile range = 5-15) during the 42-month period following training. Clinically relevant images were obtained in 99% of patients. EPs without fellowship or other advanced US training performed the majority of F-TEEs (417, 74.9%) and 94.3% (95% confidence interval [CI] = 91.4%-96.3%) had interpretable images recorded. When TTE and TEE were both performed (n = 410), image quality of TEE was superior in 378 (93.3%, 95% CI = 89.7%-95%). Indications for F-TEE included periarrest states (55.7%), cardiac arrest (32.1%), and shock (12.2%). There was one case of endotracheal tube dislodgement during TEE placement, but this was immediately identified and replaced without complication.

CONCLUSION

After initiating a mandatory group F-TEE training and credentialing program, we report the largest series to date of EP-performed resuscitative F-TEE. The majority of F-TEE examinations (75%) were performed by EPs without advanced US training beyond residency.

Role of echocardiography in a patient with suspected acute pulmonary embolism: a case report

BACKGROUND

Approximately half of pulmonary embolism cases are diagnosed in an emergency context. The classic symptoms of pulmonary embolism are absent in intensive care unit patients who are under sedation and on mechanical ventilation. In this scenario, after the development of sudden, severe hypotension, pulmonary embolism must be considered and included in a differential diagnosis according to the cause of admission. Echocardiography may be of further help in a differential diagnosis of the cause of shock.

CASE PRESENTATION

We present a case of a 44-year-old Caucasian man who was admitted to the intensive care unit with a diagnosis of community-acquired pneumonia and respiratory failure and who required invasive mechanical ventilation. During admission, the patient developed sudden, severe hypotension that was refractory to treatment. An adequate diagnosis with transthoracic echocardiography was unachievable because of a poor echocardiographic window. However, the combined use of electrocardiography and transesophageal echocardiography established pulmonary embolism as a high-probability diagnosis based on findings of right ventricular pressure overload and right ventricular dysfunction. The unfavorable hemodynamic situation of the patient prevented his transfer to carry out other complementary tests that could confirm the diagnosis of pulmonary embolism. Fibrinolytic and anticoagulant therapies were administered immediately, and a favorable clinical outcome was achieved.

CONCLUSION

This case highlights the fundamental role that echocardiography played in a patient in the intensive care unit who presented with shock secondary to pulmonary embolism with an unfavorable hemodynamic situation and in whom an unnecessary transfer to perform other complementary diagnostic tests was avoided. The combined use of electrocardiography and echocardiography provided a complete differential diagnosis, identifying the cause of shock and allowing the initiation of specific treatment without further delay. Knowledge of the echocardiographic results that are characteristic of pulmonary embolism can aid in the diagnosis.

Hemodynamic assessment of critically ill patients using a miniaturized transesophageal echocardiography probe

INTRODUCTION

Hemodynamic management in intensive care patients guided by blood pressure and flow measurements often do not sufficiently reveal common hemodynamic problems. Trans-esophageal echocardiography (TEE) allows for direct measurement of cardiac volumes and function. A new miniaturized probe for TEE (mTEE) potentially provides a rapid and simplified approach to monitor cardiac function. The aim of the study was to assess the feasibility of hemodynamic monitoring using mTEE in critically ill patients after a brief operator training period.

METHODS

In the context of the introduction of mTEE in a large ICU, 14 ICU staff specialists with no previous TEE experience received six hours of training as mTEE operators. The feasibility of mTEE and the quality of the obtained hemodynamic information were assessed. Three standard views were acquired in hemodynamically unstable patients: 1) for assessment of left ventricular function (LV) fractional area change (FAC) was obtained from a trans-gastric mid-esophageal short axis view, 2) right ventricular (RV) size was obtained from mid-esophageal four chamber view, and 3) superior vena cava collapsibility for detection of hypovolemia was assessed from mid-esophageal ascending aortic short axis view. Off-line blinded assessment by an expert cardiologist was considered as a reference. Inter-rater agreement was assessed using Chi-square tests or correlation analysis as appropriate.

RESULTS

In 55 patients, 148 mTEE examinations were performed. Acquisition of loops in sufficient quality was possible in 110 examinations for trans-gastric mid-esophageal short axis, 118 examinations for mid-esophageal four chamber and 125 examinations for mid-esophageal ascending aortic short axis view. Inter-rater agreement (Kappa) between ICU mTEE operators and the reference was 0.62 for estimates of LV function, 0.65 for RV dilatation, 0.76 for hypovolemia and 0.77 for occurrence of pericardial effusion (all P<0.0001). There was a significant correlation between the FAC measured by ICU operators and the reference (r=0.794, P (one-tailed)<0.0001).

CONCLUSIONS

Echocardiographic examinations using mTEE after brief bed-side training were feasible and of sufficient quality in a majority of examined ICU patients with good inter-rater reliability between mTEE operators and an expert cardiologist. Further studies are required to assess the impact of hemodynamic monitoring by mTEE on relevant patient outcomes.

Diagnostic bedside EUS in the intensive care unit: a single-center experience

BACKGROUND

The knowledge of bedside diagnostic EUS in critically ill patients is limited.

OBJECTIVE

To investigate the indications, feasibility, safety, and clinical utility of diagnostic EUS in the intensive care unit (ICU).

DESIGN

Retrospective.

SETTING

Tertiary-care referral teaching hospital.

PATIENTS

All consecutive patients who had EUS done in the ICU within a 6-year period.

INTERVENTION

Bedside EUS and EUS-guided FNA.

MAIN OUTCOME MEASUREMENTS

EUS indications, complications, and impact on management.

RESULTS

A total of 64 EUS procedures were performed in 63 patients (38 men, 25 women; age range 27-78 years); 1 patient underwent 2 separate EUS procedures. EUS was performed while the patients were mechanically ventilated in 70% (45/64) of cases. Indications for EUS included jaundice (n = 24), mass of unknown etiology (n = 25), unexplained pancreatitis (n = 7), and staging of known cancer (n = 3). In 5 cases, EUS was used as an alternative to other imaging modalities because of morbid obesity (n = 3) or contraindication to intravenous contrast material (n = 2). Complications included reversible oxygen desaturation (n = 4), nonsustained ventricular tachycardia (n = 1), and transient hypotension (n = 1). Overall, EUS influenced management in 97% (62/64) of cases.

LIMITATIONS

Retrospective, single-center study.

CONCLUSION

ICU-based EUS can be performed with few intraprocedural complications and can be a valuable diagnostic modality in the ICU setting. It appears to be particularly useful for determining the etiology of jaundice, masses of unknown etiology, and pancreatitis. It may have particular value as a diagnostic technique on selected patients with unstaged cancer and when morbid obesity or the inability to use intravenous contrast material precludes the use of other imaging modalities in the critically ill patient.

Transesophageal Echocardiography–Guided Hemodynamic Assessment and Management

Hemodynamic instability (shock) poses a major challenge in intensive care and is associated with increased mortality, morbidity, length of stay, and costs. The purpose of hemodynamic assessment and management is to detect the cause of hemodynamic instability in a given patient, provide actionable information for the physician, and thus help guide the management and resolution of hemodynamic instability. Although transesophageal echocardiography (TEE) has been the gold standard for hemodynamic assessment and management in the cardiac operating room, the invasive nature of conventional TEE has limited its use as a management tool in intensive care. Instead, one has seen a variety of indirect hemodynamic monitors used, despite now well understood limitations as described in a previous Critical Conversation in the July 2011 issue of this journal. Here we describe the use of TEE in intensive care as well as a new TEE system (the ImaCor hTEE system, ImaCor, Garden City, NY) with a miniaturized (approximately nasogastric tube sized), indwelling probe designed specifically for TEE-guided hemodynamic assessment and management in intensive care (hemodynamic TEE).

[Role of echocardiography in the hemodynamic monitorization of critical patients]

The use of echocardiography in intensive care units in shock patients allows us to measure various hemodynamic variables in an accurate and a non-invasive manner. By using echocardiography not only as a diagnostic technique but also as a tool for continuous hemodynamic monitorization, the intensivist can evaluate various aspects of shock states, such as cardiac output and fluid responsiveness, myocardial contractility, intracavitary pressures, heart-lung interaction and biventricular interdependence. However, to date there has been little guidance orienting echocardiographic hemodynamic parameters in the intensive care unit, and intensivists are usually not familiar with this tool. In this review, we describe some of the most important hemodynamic parameters that can be obtained at the patient bedside with transthoracic echocardiography in critically ill patients.

Aortic valve stenosis

Calcific aortic stenosis (AS) is primarily a disease of the elderly, possessing features that are biomechanical as well as systemic and inflammatory in nature, with risk factors and histopathology similar to atherosclerosis. To date no medical therapy has been shown to conclusively alter the progression of the disease, and for those with symptomatic AS, aortic valve replacement (AVR) is advocated. Factors that may alert the physician to an accelerated progression of calcific aortic valvular disease toward severe symptomatic AS include moderate aortic valve calcification, chronically dialyzed patients, and patients 80 years and older. There remains significant morbidity and mortality associated with AVR, and new techniques and technologies for AVR are being developed. For those who undergo successful AVR the long-term prognosis is good. A substantial number of patients with symptomatic AS present for anesthesia care for a variety of procedures. A thorough, modern understanding of AS and its course are necessary for the anesthesiologist to guide the patient through the perioperative period.