Diagnostic usefulness and impact on management of transesophageal echocardiography in surgical intensive care units

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.

Unanticipated critical findings on echocardiography in septic patients

BACKGROUND

Echocardiography is increasingly performed among septic patients as a routine part of evaluation and management in the intensive care unit (ICU). The rate of unanticipated critical findings (e.g., severe left or right ventricular dysfunction or pericardial tamponade) on such echocardiograms is unknown. We evaluated a retrospective cohort of septic ICU patients in whom transthoracic echocardiography was performed as a routine part of sepsis management. In addition to identifying critical findings, we defined whether each critical finding was anticipated, and whether the clinical team responded to the critical finding. The primary outcome was rate of unanticipated critical findings, which we hypothesized would occur in fewer than 5% of patients. We also performed an exploratory analysis of the association between unanticipated critical finding and mortality, controlling for severity of illness.

RESULTS

We studied 393 patients. Unanticipated critical findings were identified in 5% (95% CI 3-7%) of patients (n = 20). Among the 20 patients with unanticipated critical findings, a response to the unanticipated critical finding was identified in 12 (60%) patients. An unanticipated critical finding was not significantly associated with 28-day mortality when controlling for admission APACHE II (p = 0.27).

CONCLUSIONS

Unanticipated critical findings on echocardiograms in septic ICU patients are uncommon. The potential therapeutic relevance of echocardiography to sepsis is more likely related to hemodynamic management than to traditional cardiac diagnoses. Research studies that employ blinded echocardiograms in septic patients may anticipate unblinding for critical findings approximately 1 in every 20 echocardiograms.

Perioperative transesophageal echocardiography for non-cardiac surgery

PURPOSE

The use of transesophageal echocardiography (TEE) has evolved to include patients undergoing high-risk non-cardiac procedures and patients with significant cardiac disease undergoing non-cardiac surgery. Implementation of basic TEE education in training programs has increased across a broad spectrum of procedures in the perioperative arena. This paper describes the use of perioperative TEE in non-cardiac surgery and provides an overview of the basic TEE examination.

PRINCIPAL FINDINGS

Perioperative TEE is used to monitor hemodynamic parameters in non-cardiac procedures where there is a high risk of hemodynamic instability. Its use extends to include moderate-risk procedures for patients with significant cardiac diseases such as low ejection fraction, hypertrophic cardiomyopathy, severe valve lesions, or congenital heart disease. Vascular procedures involving the aorta, blunt trauma, and liver transplantation are all examples of procedures that may benefit from TEE. Transesophageal echocardiography examination allows assessment of volume status, ventricular function, diagnosis of gross valvular pathology and pericardial tamponade, as well as close monitoring of cardiac output, response to therapy, and the impact of ongoing surgical manipulation. In patients with unexplained and unexpected hemodynamic instability, "rescue TEE" can be used to help identify the underlying cause.

CONCLUSIONS

Perioperative TEE is emerging as a preferred tool to manage hemodynamics in high-risk procedures and in high-risk patients undergoing non-cardiac surgery. A rescue TEE examination protocol is a helpful approach for early identification of the etiology of hemodynamic instability.

The Diagnostic and Therapeutic Impact of Point-of-Care Ultrasonography in the Intensive Care Unit

PURPOSE

In light of point-of-care ultrasonography's (POCUS) recent rise in popularity, assessment of its impact on diagnosis and treatment in the intensive care unit (ICU) is of key importance.

METHODS

Ultrasound examinations were collected through an ultrasound reporting software in 6 multidisciplinary ICU units from 3 university hospitals in Canada and the United States. This database included a self-reporting questionnaire to assess the impact of the ultrasound findings on diagnosis and treatment. We retrieved the results of these questionnaires and analyzed them in relation to which organs were assessed during the ultrasound examination.

RESULTS

One thousand two hundred and fifteen ultrasound studies were performed on 968 patients. Intensivists considered the image quality of cardiac ultrasound to be adequate in 94.7% compared to 99.7% for general ultrasound ( P < .001). The median duration of a cardiac examination was 10 (interquartile range [IQR] 10) minutes compared to 5 (IQR 8) minutes for a general examination ( P < .001). Overall, ultrasound findings led to a change in diagnosis in 302 studies (24.9%) and to a change in management in 534 studies (44.0%). A change in diagnosis or management was reported more frequently for cardiac ultrasound than for general ultrasound (108 [37.1%] vs 127 [16.5%], P < .001) and (170 [58.4%] vs 270 [35.1%], P < .001). Assessment of the inferior vena cava for fluid status emerged as the critical care ultrasound application associated with the greatest impact on management.

CONCLUSION

Point-of-care ultrasonography has the potential to optimize care of the critically ill patients when added to the clinical armamentarium of the intensive care physician.

Transthoracic and transoesophageal echocardiography: a systematic review of feasibility and impact on diagnosis, management and outcome after cardiac surgery

Transthoracic and transoesophageal echocardiography are increasingly used as tools to improve clinical assessment following cardiac surgery. However, most physicians are not trained in echocardiography, and there is no widespread agreement on the feasibility, indications or effect on outcome of transthoracic or transoesophageal echocardiography for patients after cardiac surgery. We performed a systematic review of electronic databases for focused transthoracic and transoesophageal echocardiography after cardiac surgery which revealed 15 full-text articles. They consistently reported that echocardiography is feasible, whether performed by a novice or expert, and frequently resulted in important changes in diagnosis of cardiac abnormalities and their management. However, most were observational studies and there were no well-designed trials investigating the impact of echocardiography on outcome. We conclude that both transthoracic and transoesophageal echocardiography are useful following cardiac surgery.

Hemodynamic assessment in the contemporary intensive care unit: a review of circulatory monitoring devices

The assessment of the circulating volume and efficiency of tissue perfusion is necessary in the management of critically ill patients. The controversy surrounding pulmonary artery catheterization has led to a new wave of minimally invasive hemodynamic monitoring technologies, including echocardiographic and Doppler imaging, pulse wave analysis, and bioimpedance. This article reviews the principles, advantages, and limitations of these technologies and the clinical contexts in which they may be clinically useful.

Focused critical care echocardiography

OBJECTIVE

Portable ultrasound is now used routinely in many ICUs for various clinical applications. Echocardiography performed by noncardiologists, both transesophageal and transthoracic, has evolved to broad applications in diagnosis, monitoring, and management of critically ill patients. This review provides a current update on focused critical care echocardiography for the management of critically ill patients.

METHOD

Source data were obtained from a PubMed search of the medical literature, including the PubMed "related articles" search methodology.

SUMMARY AND CONCLUSIONS

Although studies demonstrating improved clinical outcomes for critically ill patients managed by focused critical care echocardiography are generally lacking, there is evidence to suggest that some intermediate outcomes are improved. Furthermore, noncardiologists can learn focused critical care echocardiography and adequately interpret the information obtained. Noncardiologists can also successfully incorporate focused critical care echocardiography into advanced cardiopulmonary life support. Formal training and proctoring are important for safe application of focused critical care echocardiography in clinical practice. Further outcomes-based research is urgently needed to evaluate the efficacy of focused critical care echocardiography.

Core review: physician-performed ultrasound: the time has come for routine use in acute care medicine

The use of ultrasound in the acute care specialties of anesthesiology, intensive care, emergency medicine, and surgery has evolved from discrete, office-based echocardiographic examinations to the real-time or point-of-care clinical assessment and interventions. "Goal-focused" transthoracic echocardiography is a limited scope (as compared with comprehensive examination) echocardiographic examination, performed by the treating clinician in acute care medical practice, and is aimed at addressing specific clinical concerns. In the future, the practice of surface ultrasound will be integrated into the everyday clinical practice as ultrasound-assisted examination and ultrasound-guided procedures. This evolution should start at the medical student level and be reinforced throughout specialist training. The key to making ultrasound available to every physician is through education programs designed to facilitate uptake, rather than to prevent access to this technology and education by specialist craft groups. There is evidence that diagnosis is improved with ultrasound examination, yet data showing change in management and improvement in patient outcome are few and an important area for future research.

ICU 2020: five interventions to revolutionize quality of care in the ICU

Intensive care units (ICUs) are an essential and unique component of modern medicine. The number of critically ill individuals, complexity of illness, and cost of care continue to increase with time. In order to meet future demands, maintain quality, and minimize medical errors, intensivists will need to look beyond traditional medical practice, seeking lessons on quality assurance from industry and aviation. Intensivists will be challenged to keep pace with rapidly advancing information technology and its diverse roles in ICU care delivery. Modern ICU quality improvement initiatives include ensuring evidence-based best practice, participation in multicenter ICU collaborations, employing state-of-the-art information technology, providing point-of-care diagnostic testing, and efficient organization of ICU care delivery. This article demonstrates that each of these initiatives has the potential to revolutionize the quality of future ICU care in the United States.

Review article: Part one: Goal-directed resuscitation--which goals? Haemodynamic targets

The use of appropriate resuscitation targets or end-points may facilitate early detection and appropriate management of shock. There is a fine balance between oxygen delivery and consumption, and when this is perturbed, an oxygen debt is generated. In this narrative review, we explore the value of global haemodynamic resuscitation end-points, including pulse rate, blood pressure, central venous pressure and mixed/central venous oxygen saturations. The evidence supporting the reliability of these parameters as end-points for guiding resuscitation and their potential limitations are evaluated.

Echocardiography in the Intensive Care Unit

As ultrasound technology improves and ultrasound availability increases, echocardiography utilization is growing within intensive care units. Although not replacing the often-needed comprehensive echocardiographic evaluation, limited bedside echocardiography promises to provide intensivists with enhanced diagnostic ability and improved hemodynamic understanding of individual patients. Routine and emergency echocardiography within the intensive care unit focuses on identifying and optimizing medically treatable conditions in a timely manner. Methods for such goal-directed assessments are presented.

[Haemodynamic monitoring in the perioperative phase. Available systems, practical application and clinical data]

A regular hydration status and compensated vascular filling are targets of perioperative fluid and volume management and, in parallel, represent precautions for sufficient stroke volume and cardiac output to maintain tissue oxygenation. The physiological and pathophysiological effects of fluid and volume replacement mainly depend on the pharmacological properties of the solutions used, the magnitude of the applied volume as well as the timing of volume replacement during surgery. In the perioperative setting surgical stress induces physiological and hormonal adaptations of the body, which in conjunction with an increased permeability of the vascular endothelial layer influence fluid and volume management. The target of haemodynamic monitoring in the operation room is to collect data on haemodynamics and global oxygen transport, which enable the anaesthetist to estimate the volume status of the vascular system. Particularly in high risk patients this may improve fluid and volume therapy with respect to maintaining cardiac output. A goal-directed volume management aiming at preventing hypovolaemia may improve the outcome after surgery. The objective of this article is to review the monitoring devices that are currently used to assess haemodynamics and filling status in the perioperative setting. Methods and principles for measuring haemodynamic variables, the measured and calculated parameters as well as clinical benefits and shortcomings of each device are described. Furthermore, the results for monitoring devices from clinical studies of goal-directed fluid and volume therapy which have been published will be discussed.

[Echocardiography in the Intensive Care Unit]

The echocardiography can provide important and relevant information and the critically ill patient presents a challenge for the echocardiographer: from limitations in image acquisition to interpretation in the context of rapid physiological and intervention changes. The most frequent reason for requesting an echocardiogram in the ICU is probably to assess left ventricular function. In any case, information of direct relevance for clinical management can in relationship to abnormalities of structure and function can be obtained and used to estimate pulmonary arterial and venous pressures. It can help to investigate the consequences of myocardial ischemia, valvular dysfunction and pericardial disease and detect changes characteristic of specific conditions (e.g. sepsis, pulmonary thromboembolism), although this must be interpreted in the context of each individual patient. The echocardiography also can be used to monitor the therapeutic interventions. The applications of echocardiography in the critical care setting are reviewed, with special emphasis on the assessment of cardiac physiology.

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.

The importance of transesophageal echocardiography in diagnosis of pericardial tamponade after cardiac surgery

BACKGROUND AND AIM OF THE STUDY

Despite the fact that there is a simple and effective treatment for pericardial tamponade (PCT), delayed diagnosis can cause serious morbidities or even mortality. In this study, we discuss the management and the diagnostic procedures of PCT.

MATERIALS AND METHODS

Sixty-two patients with suspected PCT were initially evaluated with transthoracic echocardiography (TTE) and then with transesophageal echocardiography (TEE). Forty-nine (79%) patients were chosen for surgery after TEE displayed a suspected PCT diagnosis. Patients with suspected PCT were divided into two groups: Early-phase PCT (symptoms developed within 72 hours) and late-phase PCT (symptoms developed after 72 hours).

RESULTS

Thirty-five (56%) patients were in the early phase and 27 (44%) patients were in the late phase. In 13 out of 22 (59%) cases, from both early and late phases, TTE findings showed no PCT, but TEE findings showed a positive PCT diagnosis. All 13 of the cases where TEE was positive after a negative TTE were confirmed by surgery. Overall, the PCT diagnoses in 48 out of 49 patients were confirmed during surgery.

DISCUSSION

The role of echocardiography in PCT diagnosis is shown to be extremely important in some clinical cases, such as in patients during the postoperative period after cardiac surgery. Furthermore, particularly when TTE does not provide complete imaging of the pericardial sac, TEE should be mandatory. We recommend that even patients with a negative diagnosis of PCT from TTE should undergo further evaluation with TEE.

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.

Bedside echocardiography in the assessment of the critically ill

Advances in ultrasound technology continue to enhance its diagnostic applications in daily medical practice. Bedside echocardiographic examination has become useful to properly trained cardiologists, anesthesiologists, intensivists, surgeons, and emergency room physicians. Cardiac ultrasound can permit rapid, accurate, and noninvasive diagnosis of a broad range of acute cardiovascular pathologies. Although transesophageal echocardiography was once the principal diagnostic approach using ultrasound to evaluate intensive care unit patients, advances in ultrasound imaging, including harmonic imaging, digital acquisition, and contrast for endocardial enhancement, has improved the diagnostic yield of transthoracic echocardiography. Ultrasound devices continue to become more portable, and hand-carried devices are now readily available for bedside applications. This article discusses the application of bedside echocardiography in the intensive care unit. The emphasis is on echocardiography and cardiovascular diagnostics, specifically on goal-directed bedside cardiac ultrasonography.

A Systematic Approach to Substernal Epicardial Echocardiographic Examination

OBJECTIVE

The importance of echocardiography in the perioperative management of cardiac surgical patients is widely appreciated. A modified mediastinal drain has been developed, which allows the introduction of a standard TEE probe in a closed-ended sleeve coupled with the drain to permit epicardial echocardiographic imaging after chest closure (substernal epicardial echocardiography [SEE]). The aim of the present study was to develop a standardized and comprehensive SEE examination sequence to allow repeatable examinations with a single movement of the TEE probe inside the drain.

DESIGN

Prospective observational protocol.

SETTING

Tertiary care university hospital.

PARTICIPANTS

Ten adult patients undergoing elective cardiac surgery.

INTERVENTIONS

Twenty-three SEE examinations in 10 patients undergoing elective myocardial revascularization to develop a standard examination sequence.

MEASUREMENTS AND MAIN RESULTS

The examination sequence includes 11 views with all the structures relevant for postoperative monitoring. The entire sequence is performed with a single in-out movement of the transesophageal probe to minimize discomfort to patients and the risk of damaging the tube.

CONCLUSIONS

This new approach to the perioperative monitoring of cardiac surgical patients represents an option for patients in whom TEE is contraindicated or multiple examinations are anticipated because SEE examinations can be performed without the need for sedation in awake patients.

Flow rate, syringe size and architecture are critical to start-up performance of syringe pumps

BACKGROUND AND OBJECTIVE

Significant start-up delays are inherent to syringe infusion pumps, particularly at low infusion rates, as routinely used in children's anaesthesia and intensive care. Such delays are mainly the result of engagement of gears in the mechanical drive or compliance of the syringe assembly. The purpose of the present study was to determine the effect of flow rate, syringe size and syringe architecture on fluid delivery during infusion start-up.

METHODS

Elapsed time from infusion start to achievement of steady-state flow was gravimetrically determined for various infusion rates (0.1, 0.5, 1 mL h-1), different syringe sizes (10-, 20-, 30-, 50-mL) and syringes of two different brands (BD and Codan). Four measurements for each condition were performed with two identical Alaris Asena GH syringe infusion pumps (total of eight experiments). Statistical analysis was done by two-way ANOVA with Bonferroni's post-test; P < 0.05 was considered significant.

RESULTS

Start-up time was from 3.6 +/- 0.9 min (BD 10-mL syringe, 1.0 mL h-1) to 74.5 +/- 26.6 min (BD 50-mL syringe, 0.1 mL h-1). Overall, the start-up time markedly increased with lower flow rate (0.1 mL h-1 vs. 1 mL h-1; P < 0.0001), larger syringe size (50 mL vs. 10 mL; P < 0.01), and the BD brand in comparison with the Codan syringes (P < 0.01).

CONCLUSIONS

Highest possible flow rate, smaller sized syringes and syringe plungers with reduced compressibility should be preferred in order to avoid significant start-up delays in fluid delivery.

Bedside ultrasonography in the ICU: part 1

Ultrasonography has become an invaluable tool in the management of critically ill patients. Its safety and portability allow for use at the bedside to provide rapid, detailed information regarding the cardiovascular system and the function and anatomy of certain internal organs. Echocardiography can noninvasively elucidate cardiac function and structure. This information is vital in the management hemodynamically unstable patients in the ICU. In addition, ultrasonography has particular value for the assessment and safe drainage of pleural and intra-abdominal fluid and the placement of central venous catheters. A new generation of portable, battery-powered, inexpensive, hand-carried ultrasound devices have recently become available; these devices can provide immediate diagnostic information not assessable by physical examination alone and allow for ultrasound-guided thoracocentesis, paracentesis, and central venous cannulation. This two-part article reviews the application of bedside ultrasonography in the ICU.

Bedside Ultrasonography in the ICU

This is the second of a two-part review on the application of bedside ultrasonography in the ICU. In this part, the following procedures will be covered: (1) echocardiography and cardiovascular diagnostics (second part); (2) the use of bedside ultrasound to facilitate central-line placement and to aid in the care of patients with pleural effusions and intra-abdominal fluid collections; (3) the role of hand-carried ultrasound in the ICU; and (4) the performance of bedside ultrasound by the intensivist. The safety and utility of bedside ultrasonography performed by adequately trained intensivists has now been well demonstrated. This technology, as a powerful adjunct to the physical examination, will become an indispensable tool in the management of critically ill patients.