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

Transoesophageal echocardiography beyond the echo-laboratory. An expert consensus paper of the working group of echocardiography of the hellenic society of cardiology

Transoesophageal echocardiography (TOE) is a well-established and valid imaging modality, providing more accurate and of higher quality information than transthoracic echocardiography (TTE) for several specific diagnoses and recently a useful guide of an increasing number of catheter-based and surgical interventions. The present paper represents an effort by the Echocardiography Working Group (WG) of the Hellenic Society of Cardiology to state the essential steps of the TOE exam performed beyond the echo lab: a) in the operating rooms intraoperatively during either transcatheter interventions, or cardiothoracic surgery and b) in the intensive care unit for critically ill patients' monitoring. This paper includes information and tips and tricks about the pre-procedural evaluation, the procedural echocardiographic guidance, and post-procedural evaluation of the result and potential complications.

ISCCM Guidelines for Hemodynamic Monitoring in the Critically Ill

Hemodynamic assessment along with continuous monitoring and appropriate therapy forms an integral part of management of critically ill patients with acute circulatory failure. In India, the infrastructure in ICUs varies from very basic facilities in smaller towns and semi-urban areas, to world-class, cutting-edge technology in corporate hospitals, in metropolitan cities. Surveys and studies from India suggest a wide variation in clinical practices due to possible lack of awareness, expertise, high costs, and lack of availability of advanced hemodynamic monitoring devices. We, therefore, on behalf of the Indian Society of Critical Care Medicine (ISCCM), formulated these evidence-based guidelines for optimal use of various hemodynamic monitoring modalities keeping in mind the resource-limited settings and the specific needs of our patients. When enough evidence was not forthcoming, we have made recommendations after achieving consensus amongst members. Careful integration of clinical assessment and critical information obtained from laboratory data and monitoring devices should help in improving outcomes of our patients.

How to cite this article

Kulkarni AP, Govil D, Samavedam S, Srinivasan S, Ramasubban S, Venkataraman R, et al. ISCCM Guidelines for Hemodynamic Monitoring in the Critically Ill. Indian J Crit Care Med 2022;26(S2):S66-S76.

Transesophageal echocardiography-associated tracheal microaspiration and ventilator-associated pneumonia in intubated critically ill patients: a multicenter prospective observational study

BACKGROUND

Microaspiration of gastric and oropharyngeal secretions is the main causative mechanism of ventilator-associated pneumonia (VAP). Transesophageal echocardiography (TEE) is a routine investigation tool in intensive care unit and could enhance microaspiration. This study aimed at evaluating the impact of TEE on microaspiration and VAP in intubated critically ill adult patients.

METHODS

It is a four-center prospective observational study. Microaspiration biomarkers (pepsin and salivary amylase) concentrations were quantitatively measured on tracheal aspirates drawn before and after TEE. The primary endpoint was the percentage of patients with TEE-associated microaspiration, defined as: (1) ≥ 50% increase in biomarker concentration between pre-TEE and post-TEE samples, and (2) a significant post-TEE biomarker concentration (> 200 μg/L for pepsin and/or > 1685 IU/L for salivary amylase). Secondary endpoints included the development of VAP within three days after TEE and the evolution of tracheal cuff pressure throughout TEE.

RESULTS

We enrolled 100 patients (35 females), with a median age of 64 (53-72) years. Of the 74 patients analyzed for biomarkers, 17 (23%) got TEE-associated microaspiration. However, overall, pepsin and salivary amylase levels were not significantly different between before and after TEE, with wide interindividual variability. VAP occurred in 19 patients (19%) within 3 days following TEE. VAP patients had a larger tracheal tube size and endured more attempts of TEE probe introduction than their counterparts but showed similar aspiration biomarker concentrations. TEE induced an increase in tracheal cuff pressure, especially during insertion and removal of the probe.

CONCLUSIONS

We could not find any association between TEE-associated microaspiration and the development of VAP during the three days following TEE in intubated critically ill patients. However, our study cannot formally rule out a role for TEE because of the high rate of VAP observed after TEE and the limitations of our methods.

Ultrasonography in the Critical Care Unit

Purpose of Review

This article summarizes the utility and evidence supporting the use of ultrasound exams in the intensive care unit.

Recent Findings

Point-of-care ultrasonography (POCUS) is widely used by intensivists managing critically ill patients whereby they can accurately and rapidly assess for many pathologies such as pneumothorax, pulmonary edema, hydronephrosis, hemoperitoneum, and deep vein thrombosis among others. Basic and advanced critical care echocardiography, including transesophageal echocardiography, are routinely performed to determine the etiology of hemodynamic instability in undifferentiated shock and to guide subsequent therapy. The use of POCUS in the assessment of volume status is controversial with studies demonstrating that respiratory variation of the IVC is not reliable and with analysis of aortic blood flow velocity after passive leg raising maneuvers being the most promising.

Summary

Point-of-care ultrasonography allows frontline clinicians to make real-time diagnoses and treatment decisions. This article will provide the reader with a broad overview of this important topic.

Electronic supplementary material

The online version of this article (10.1007/s11886-020-01393-z) contains supplementary material, which is available to authorized users.

Hemodynamic monitoring using trans esophageal echocardiography in patients with shock

Circulatory shock is a life-threatening condition responsible for inadequate tissue perfusion. The objectives of hemodynamic monitoring in this setting are multiple: identifying the mechanisms of shock (hypovolemic, distributive, cardiogenic, obstructive); choosing the adequate therapeutic intervention, and evaluating the patient's response. Echocardiography is proposed as a first line tool for this assessment in the intensive care unit. As compared to trans-thoracic echocardiography (TTE), trans-esophageal echocardiography (TEE) offers a better echogenicity and is the best way to evaluate deep anatomic structures. The therapeutic implication of TEE leads to frequent changes in clinical management. It also allows depicting sources of inaccuracy of thermodilution-based hemodynamic monitoring. It is a semi invasive tool with a low rate of complications. The first step in the hemodynamic evaluation of shock is to characterize the mechanisms of circulatory failure among hypovolemia, vasoplegia, cardiac dysfunction, and obstruction. Echocardiographic evaluation includes evaluation of LV systolic and diastolic function, as well as RV function, pericardium, measure of stroke volume and cardiac output, and evaluation of hypovolemia and fluid responsiveness. TEE can be used as a semi-continuous monitoring tool and can be repeated before and after therapeutic interventions (vasopressors, inotropes, fluid therapy, specific treatment such as pericardial effusion evacuation) to evaluate efficacy and tolerance of therapeutic interventions. In conclusion, TEE plays an important role in the management of circulatory failure when TTE is not enough to answer to the questions, although it is not a continuous tool of monitoring. TEE results must be integrated in a global evaluation, the first step being clinical examination. Whether TEE-directed therapy and close hemodynamic monitoring of shock has an impact on outcome remains debated.

Continuous cardiac output assessment or serial echocardiography during septic shock resuscitation?

Septic shock is the leading cause of cardiovascular failure in the intensive care unit (ICU). Cardiac output is a primary component of global oxygen delivery to organs and a sensitive parameter of cardiovascular failure. Any mismatch between oxygen delivery and rapidly varying metabolic demand may result in tissue dysoxia, hence organ dysfunction. Since the intricate alterations of both vascular and cardiac function may rapidly and widely change over time, cardiac output should be measured repeatedly to characterize the type of shock, select the appropriate therapeutic intervention, and evaluate patient's response to therapy. Among the numerous techniques commercially available for measuring cardiac output, transpulmonary thermodilution (TPT) provides a continuous monitoring with external calibration capability, whereas critical care echocardiography (CCE) offers serial hemodynamic assessments. CCE allows early identification of potential sources of inaccuracy of TPT, including right ventricular failure, severe tricuspid or left-sided regurgitations, intracardiac shunt, very low flow states, or dynamic left ventricular outflow tract obstruction. In addition, CCE has the unique advantage of depicting the distinct components generating left ventricular stroke volume (large cavity size vs. preserved contractility), providing information on left ventricular diastolic properties and filling pressures, and assessing pulmonary artery pressure. Since inotropes may have deleterious effects if misused, their initiation should be based on the documentation of a cardiac dysfunction at the origin of the low flow state by CCE. Experts widely advocate using CCE as a first-line modality to initially evaluate the hemodynamic profile associated with shock, as opposed to more invasive techniques. Repeated assessments of both the efficacy (amplitude of the positive response) and tolerance (absence of side-effect) of therapeutic interventions are required to best guide patient management. Overall, TPT allowing continuous tracking of cardiac output variations and CCE appear complementary rather than mutually exclusive in patients with septic shock who require advanced hemodynamic monitoring.

Impact of Critical Care Transesophageal Echocardiography in Medical-Surgical ICU Patients: Characteristics and Results From 274 Consecutive Examinations

OBJECTIVE

Critical care echocardiography has become an integral tool in the assessment and management of critically ill patients. Critical care transesophageal echocardiography (TEE) offers diagnostic reliability, superior image quality, and an expanded diagnostic scope to transthoracic echocardiography. Despite its favorable attributes, TEE use in North American intensive care units (ICUs) remains relatively undescribed. In this article, we seek to characterize the feasibility, indications, and clinical impact of a critical care TEE program.

DESIGN

Retrospective, observational study.

SETTING

Tertiary care, academic critical care program consisting of 2 hospitals in Ontario, Canada.

PARTICIPANTS

Consecutive critical care TEE examinations on ICU patients performed between December 2012 and December 2016.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Consecutive critical care TEE studies on ICU patients from December 1, 2012, to December 31, 2016, were reviewed. The TEEs performed on cardiac surgery patients and those without reports were excluded. Examination details, including indications, complications, examination complexity (number of views, Doppler techniques), and clinical recommendations were aggregated and analyzed. Two hundred seventy-four TEE studies were performed by 38 operators. Common indications for TEE studies were hemodynamic instability (45.2%), assessment for infective endocarditis (22.2%), and cardiac arrest (20.1%). A change in patient management was proposed following 79.5% of TEE studies. Thirty-eight percent of TEE studies were performed during evening hours or on weekends. There were no mechanical complications.

CONCLUSIONS

Our observational data support intensivist-performed TEE as being safe and therapeutically influential across a broad range of indications. Our program's demonstrated feasibility and impact may act as a model for TEE adoption in other North American ICUs.

Non-Invasive Monitoring of Cardiac Output in Critical Care Medicine

Critically ill patients require close hemodynamic monitoring to titrate treatment on a regular basis. It allows administering fluid with parsimony and adjusting inotropes and vasoactive drugs when necessary. Although invasive monitoring is considered as the reference method, non-invasive monitoring presents the obvious advantage of being associated with fewer complications, at the expanse of accuracy, precision, and step-response change. A great many methods and devices are now used over the world, and this article focuses on several of them, providing with a brief review of related underlying physical principles and validation articles analysis. Reviewed methods include electrical bioimpedance and bioreactance, respiratory-derived cardiac output (CO) monitoring technique, pulse wave transit time, ultrasound CO monitoring, multimodal algorithmic estimation, and inductance thoracocardiography. Quality criteria with which devices were reviewed included: accuracy (closeness of agreement between a measurement value and a true value of the measured), precision (closeness of agreement between replicate measurements on the same or similar objects under specified conditions), and step response change (delay between physiological change and its indication). Our conclusion is that the offer of non-invasive monitoring has improved in the past few years, even though further developments are needed to provide clinicians with sufficiently accurate devices for routine use, as alternative to invasive monitoring devices.

Hemodynamic Assessment of Patients With Septic Shock Using Transpulmonary Thermodilution and Critical Care Echocardiography: A Comparative Study

BACKGROUND

To assess the agreement between transpulmonary thermodilution (TPT) and critical care echocardiography (CCE) in ventilated patients with septic shock.

METHODS

Ventilated patients in sinus rhythm requiring advanced hemodynamic assessment for septic shock were included in this prospective multicenter descriptive study. Patients were assessed successively using TPT and CCE in random order. Data were interpreted independently at bedside by two investigators who proposed therapeutic changes on the basis of predefined algorithms. TPT and CCE hemodynamic assessments were reviewed offline by two independent experts who identified potential sources of discrepant results by consensus. Lactate clearance and outcome were studied.

RESULTS

A total of 137 patients were studied (71 men; age, 61 ± 15 years; Simplified Acute Physiologic Score, 58 ± 18; Sequential Organ Failure Assessment, 10 ± 3). TPT and CCE interpretations at bedside were concordant in 87/132 patients (66%) without acute cor pulmonale (ACP), resulting in a moderate agreement (kappa, 0.48; 95% CI, 0.37-0.60). Experts' adjudications were concordant in 100/129 patients without ACP (77.5%), resulting in a good intertechnique agreement (kappa, 0.66; 95% CI, 0.55-0.77). In addition to ACP (n = 8), CCE depicted a potential source of TPT inaccuracy in 8/29 patients (28%). Lactate clearance at H6 was similar irrespective of the concordance of online interpretations of TPT and CCE (55/84 [65%] vs 32/45 [71%], P = .55). ICU and day 28 mortality rates were similar between patients with concordant and discordant interpretations (29/87 [36%] vs 13/45 [29%], P = .60; and 31/87 [36%] vs 16/45 [36%], P = .99, respectively).

CONCLUSIONS

Agreement between TPT and CCE was moderate when interpreted at bedside and good when adjudicated offline by experts, but without impact on lactate clearance and mortality.

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.

The Use of Ultrasound in Caring for Patients with Sepsis

Echocardiography is a noninvasive and accurate tool used in the intensive care unit to assess cardiac function and monitor hemodynamics in shocked patients. During severe sepsis or septic shock, several mechanisms can lead to hemodynamic failure and have to be quickly and precisely diagnosed to propose adequate, personalized, and timely hemodynamic therapy. Echocardiography truly provides intensivists with this diagnostic possibility, whether or not there is fluid responsiveness, cardiac dysfunction, or persistent vasoplegia. Acquiring skills in critical care echocardiography is mandatory in improving management and monitoring of patients with sepsis at the bedside. How critical care echocardiography in managing patients with septic shock improves prognosis remains to be elucidated.

Hemodynamic assessment of ventilated ICU patients with cardiorespiratory failure using a miniaturized multiplane transesophageal echocardiography probe

PURPOSE

To assess the feasibility, image quality, diagnostic accuracy, therapeutic impact and tolerance of diagnostic and hemodynamic assessment using a novel miniaturized multiplane transesophageal echocardiography (TEE) probe in ventilated ICU patients with cardiopulmonary compromise.

STUDY DESIGN

Prospective, descriptive, single-center study.

METHODS

Fifty-seven ventilated patients with acute circulatory or respiratory failure were assessed, using a miniaturized multiplane TEE probe and a standard TEE probe used as reference, randomly by two independent experienced operators. Measurements of hemodynamic parameters were independently performed off-line by a third expert. Diagnostic groups of acute circulatory failure (n = 5) and of acute respiratory failure (n = 3) were distinguished. Hemodynamic monitoring was performed in 9 patients using the miniaturized TEE probe. TEE tolerance and therapeutic impact were reported.

RESULTS

The miniaturized TEE probe was easier to insert than the standard TEE probe. Despite lower imaging quality of the miniaturized TEE probe, the two probes had excellent diagnostic agreement in patients with acute circulatory failure (Kappa: 0.95; 95% CI: 0.85-1) and with acute respiratory failure (Kappa: 1; 95% CI: 1.0-1.0). Accordingly, therapeutic strategies derived from both TEE examinations were concordant (Kappa: 0.82; 95% CI: 0.66-0.97). The concordance between quantitative hemodynamic parameters obtained with both TEE probes was also excellent. No relevant complication secondary to TEE probes insertion occurred.

CONCLUSIONS

Hemodynamic assessment of ventilated ICU patients with cardiopulmonary compromise using a miniaturized multiplane TEE probe appears feasible, well-tolerated, and relevant in terms of diagnostic information and potential therapeutic impact. Further larger-scale studies are needed to confirm these preliminary results.

Prospective assessment of a score for assessing basic critical-care transthoracic echocardiography skills in ventilated critically ill patients

Background

We studied a score for assessing basic transthoracic echocardiography (TTE) skills exhibited by residents who examined critically ill patients receiving mechanical ventilation.

Methods

We conducted a prospective study in the 16 residents who worked in our medical-surgical ICU between 1 May 2008 and 1 November 2009. The residents received theoretical teaching (two hours) then performed supervised TTEs during their six-month rotation. Their basic TTE skills in mechanically ventilated patients were evaluated after one (M1), three (M3), and six (M6) months by two experts, who used a scoring system devised for the study. After scoring, residents gave their hemodynamic diagnosis and suggested a treatment.

Results

The 4 residents with previous TTE skills obtained a significantly higher total score than did the 12 novices at M1 (18 (16 to 19) versus 13 (10 to 15), respectively, P = 0.03). In the novices, the total score increased significantly during training (M1, 13 (10 to 14); M3, 15 (12 to 16); and M6, 17 (15 to 18); P < 0.001) and correlated significantly with the number of supervised TTEs (r = 0.68, P < 0.0001). In the overall population, agreement with experts regarding the diagnosis and treatment was associated with a significantly higher total score (17 (16 to 18) versus 13 (12 to 16), P = 0.002). A total score ≥ 19/20 points had 100% specificity (95% confidence interval, 79 to 100%) for full agreement with the experts regarding the diagnosis and treatment.

Conclusions

Our results validate the scoring system developed for our study of the assessment of basic critical-care TTE skills in residents.

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.

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.

Prolonged Transesophageal Echocardiography Use in the ICU

Transesophageal echocardiography (TEE) has gained increasing popularity in the operating room and intensive care settings. The use of TEE can often times diagnose pathology that is missed by transthoracic echocardiography (TTE); in addition, it can be used as a guide to continuously monitor a patient’s hemodynamics, along with observing the direct cardiac effects of fluid and vasopressor therapy. We present a case of acute fulminant hepatic failure in the ICU, where TEE allowed a rapid diagnosis. We performed prolonged TEE monitoring (72 hours) of the patient to monitor the patient’s response to therapeutic interventions. We also discuss the diagnostic and therapeutic implications of prolonged TEE placement in the ICU. In addition, particular strategies to optimize the benefit and minimize the risk of this exciting, yet underutilized, technology are discussed.

International expert statement on training standards for critical care ultrasonography

Training in ultrasound techniques for intensive care medicine physicians should aim at achieving competencies in three main areas: (1) general critical care ultrasound (GCCUS), (2) "basic" critical care echocardiography (CCE), and (3) advanced CCE. A group of 29 experts representing the European Society of Intensive Care Medicine (ESICM) and 11 other critical care societies worldwide worked on a potential framework for organizing training adapted to each area of competence. This framework is mainly aimed at defining minimal requirements but is by no means rigid or restrictive: each training organization can be adapted according to resources available. There was 100% agreement among the participants that general critical care ultrasound and "basic" critical care echocardiography should be mandatory in the curriculum of intensive care unit (ICU) physicians. It is the role of each critical care society to support the implementation of training in GCCUS and basic CCE in its own country.

Echocardiography in the sepsis syndromes

Purpose of the review

Non-invasiveness and instantaneous diagnostic capability are prominent features of the use of echocardiography in critical care. Sepsis and septic shock represent complex situations where early hemodynamic assessment and support are among the keys to therapeutic success. In this review, we discuss the range of applications of echocardiography in the management of the septic patient, and propose an echocardiography-based goal-oriented hemodynamic approach to septic shock.

Recent findings

Echocardiography can play a key role in the critical septic patient management, by excluding cardiac causes for sepsis, and mostly by guiding hemodynamic management of those patients in whom sepsis reaches such a severity to jeopardize cardiovascular function. In recent years, there have been both increasing evidence and diffusion of the use of echocardiography as monitoring tool in the patients with hemodynamic compromise. Also thanks to echocardiography, the features of the well-known sepsis-related myocardial dysfunction have been better characterized. Furthermore, many of the recent echocardiographic indices of volume responsiveness have been validated in populations of septic shock patients.

Conclusion

Although not proven yet in terms of patient outcome, echocardiography can be regarded as an ideal monitoring tool in the septic patient, as it allows (a) first line differential diagnosis of shock and early recognition of sepsis-related myocardial dysfunction; (b) detection of pre-existing cardiac pathology, that yields precious information in septic shock management; (c) comprehensive hemodynamic monitoring through a systematic approach based on repeated bedside assessment; (d) integration with other monitoring devices; and (e) screening for cardiac source of sepsis.

Use of transesophageal echocardiography in burns:a retrospective review

Transesophageal echocardiography (TEE) is a useful tool in the evaluation and management of critically ill patients. However, it has not been studied in the burn population. The purpose of this review is to describe the safety and utility of TEE in the management of acute burns. This retrospective review included all acute burn inpatients who underwent TEE during a 5-year period at our regional burn center. TEE board-certified anesthesiologists performed all studies. We reviewed the chart of patients who underwent TEE, the indication for TEE, the effect of TEE on clinical management, and complications resulting from TEE. Seventeen burn patients underwent TEE during the review period. The median age was 45.4 years. Fourteen of 17 patients were men (82%). Median TBSA burn was 43.4%. Seven patients (41%) were on vasopressors or inotropic agents at the time of TEE. The main indications for TEE were hypotension and bacteremia. Findings included hypovolemia, mitral valve vegetation, pulmonary hypertension, pericardial effusion, fluid overload, right heart failure, and normal TEE. Therapeutic changes occurred after TEE in two patients; these included initiation of inotropic support and antibiotics. There were no complications identified in association with TEE. TEE is a safe procedure that serves multiple diagnostic purposes. TEE is being used to better understand the fluid status and cardiac physiology of the critically ill burn patient.

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.

Intracardiac transvenous echocardiography is superior to both precordial Doppler and transesophageal echocardiography techniques for detecting venous air embolism and catheter-guided air aspiration

BACKGROUND

Venous air embolism (VAE) is a potentially fatal complication during surgical procedures with patients in the sitting position. Since methods for detection of persistent low-volume VAE and targeted air aspiration are limited, we tested the hypotheses that transvenous intracardiac echocardiography (ICE) 1) improves detection of small air emboli in comparison to transesophageal echocardiography (TEE) and precordial Doppler monitoring (PCD) techniques, and that 2) image-guided multiorifice central venous catheter manipulation improves air recovery in moderate and large VAE, when compared with aspiration with the multiorifice central venous catheter in a static position.

METHODS AND RESULTS

Adult swine (73 +/- 4.6 kg, n = 7) were premedicated, anesthetized with propofol and fentanyl, endotracheally intubated, mechanically ventilated, and placed in a 45 degrees head-up position. First, nine different small volumes of air emboli (0.05-1 mL) were randomly injected via an ear vein, and VAE detection methods were applied in random order. For 378 small volume air injections, ICE had a much higher sensitivity (82.5%, P < 0.0001) on the analysis of VAE detection than TEE (52.8%) or PCD (46.8%), with no difference (P = 0.571) between TEE and PCD. An injected air volume as small as 0.15 mL was detected by ICE in 90% of injections performed, whereas PCD and TEE detected only half of the boluses of 0.25-0.30 mL of air, and required boluses of 0.4-1.0 mL to achieve 100% detection. Air recovery was assessed in a second series of moderate VAE (2, 5, 10 mL); image-guided aspiration-catheter manipulation recovered significantly more (34.1% vs 17.2%, P < 0.0001) intracardiac air than without catheter manipulation. In a third series of injections of large air volumes (25, 50, and 100 mL), air recovery was not significantly different with ultrasound-guided aspiration (41.3% vs 31.8%, P = 0.11).

CONCLUSION

Small air emboli are detected by ICE with much greater sensitivity compared with both PCD and TEE techniques. Furthermore, recovery of embolized air is enhanced by image-guided manipulation of a multiorifice central venous catheter. Clinical studies are required to assess this technique during surgery with patients in the sitting position.

Echocardiography practice, training and accreditation in the intensive care: document for the World Interactive Network Focused on Critical Ultrasound (WINFOCUS)

Echocardiography is increasingly used in the management of the critically ill patient as a non-invasive diagnostic and monitoring tool. Whilst in few countries specialized national training schemes for intensive care unit (ICU) echocardiography have been developed, specific guidelines for ICU physicians wishing to incorporate echocardiography into their clinical practice are lacking. Further, existing echocardiography accreditation does not reflect the requirements of the ICU practitioner. The WINFOCUS (World Interactive Network Focused On Critical UltraSound) ECHO-ICU Group drew up a document aimed at providing guidance to individual physicians, trainers and the relevant societies of the requirements for the development of skills in echocardiography in the ICU setting. The document is based on recommendations published by the Royal College of Radiologists, British Society of Echocardiography, European Association of Echocardiography and American Society of Echocardiography, together with international input from established practitioners of ICU echocardiography. The recommendations contained in this document are concerned with theoretical basis of ultrasonography, the practical aspects of building an ICU-based echocardiography service as well as the key components of standard adult TTE and TEE studies to be performed on the ICU. Specific issues regarding echocardiography in different ICU clinical scenarios are then described. Obtaining competence in ICU echocardiography may be achieved in different ways - either through completion of an appropriate fellowship/training scheme, or, where not available, via a staged approach designed to train the practitioner to a level at which they can achieve accreditation. Here, peri-resuscitation focused echocardiography represents the entry level--obtainable through established courses followed by mentored practice. Next, a competence-based modular training programme is proposed: theoretical elements delivered through blended-learning and practical elements acquired in parallel through proctored practice. These all linked with existing national/international echocardiography courses. When completed, it is anticipated that the practitioner will have performed the prerequisite number of studies, and achieved the competency to undertake accreditation (leading to Level 2 competence) via a recognized National or European examination and provide the appropriate required evidence of competency (logbook). Thus, even where appropriate fellowships are not available, with support from the relevant echocardiography bodies, training and subsequently accreditation in ICU echocardiography becomes achievable within the existing framework of current critical care and cardiological practice, and is adaptable to each countrie's needs.

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.

[Transesophageal echocardiography for non-cardiac surgery patients: superfluous luxury or essential diagnostic tool?]

BACKGROUND

The value of transesophageal echocardiography (TEE) in non-cardiac critically ill patients has barely been studied.

MATERIALS AND METHODS

Over a period of 4 years TEE was used prospectively to evaluate patients with acute hemodynamic instability in non-cardiac critically ill patients in addition to standard care.

RESULTS

A total of 363 TEE studies were performed in 339 selected patients. Volume depletion (169/47%) and regional wall motion abnormalities (97/27%) were the most frequent findings followed by global left ventricular dysfunction (79/22%). Of the TEE studies, 203 (56%) provided additional information with therapeutic relevance in 164 (45%) cases.

CONCLUSIONS

Transesophageal echocardiography provides additional information in critically ill non-cardiac patients with unexplained hemodynamic instability. In the majority of cases a clinical diagnosis is confirmed or improvement of volume resuscitation and catecholamine therapy can be achieved. In the minority of patients the results of TEE lead to distinct changes in medical management. Whether this improved diagnostic accuracy favours outcome, still needs to be evaluated.

Echocardiographic measurement of ventricular function

PURPOSE OF REVIEW

We review new findings concerning ventricular function in patients in intensive care units with shock or unexplained respiratory distress syndrome analyzed using echocardiography.

RECENT FINDINGS

Bedside echocardiography is not only an imaging technique but should be considered as a hemodynamic method. Left-ventricular systolic function can be assessed in daily clinical practice by measuring shortening fraction, fraction area change and ejection fraction. But these indices are dependent on load conditions. Index of myocardial performance can be also used. Rate of left-ventricular pressure increase may be measured from mitral regurgitation. Other indices such a maximal elastance and preload-adjusted maximal power were developed to evaluate myocardial systolic function but are not still used in clinical practice in patients in intensive care. Cardiac output measurement can be calculated easily from aortic annulus diameter and the velocity time integral of aortic blood flow. To complete the assessment of ventricular function, left-ventricular diastolic function and pressure as well as right ventricular size, septal movement and right pressures should be analyzed.

SUMMARY

Using echocardiography the intensivist can examine both the mechanism and the cause of shock or pulmonary edema. It is time to increase the use of this technique in intensive care units.

A New Window of Opportunity in Echocardiography

BACKGROUND

Improvements in echocardiographic technology have made technically difficult studies a rare entity. However, physical barriers such as bandages, inability for patients to turn because of intubation, arterial lines, and organ and life support machines make echocardiographic imaging challenging.

METHODS

We performed echocardiographic imaging from left and right posterior thoracic approach using acoustic properties of pleural fluid to assist in obtaining good imaging windows in patients who had pleural effusion (PE). In this study we describe one author's (T. Z. N.) experience with the mid to lower posterior thoracic window in 18 patients who had PE and in whom conventional transthoracic windows either provided suboptimal images or incomplete clinical information.

RESULTS

The posterior approach allowed excellent differentiation of pericardial effusion versus PE, detection of pericardial disease and pericardial infiltration, and excellent endocardial border definition of left and right ventricle in those with poor anterior transthoracic windows. Native and prosthetic aortic valve gradients could be assessed adequately as a result of perfectly parallel Doppler alignment beam to left ventricular outflow tract and aortic valve. In addition, right posterior thoracic window provided views comparable with subcostal view and allowed visualization of inferior vena cava, right atrium, and liver.

CONCLUSION

In patients with PE, imaging from low to midposterior thorax can provide additional diagnostic echocardiographic images and should be used in patients in whom conventional images are technically difficult or require additional information.