Use of ultrasound in the ICU

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.

Haemodynamic monitoring in the intensive care unit: results from a web-based Swiss survey

Background. The aim of this survey was to describe, in a situation of growing availability of monitoring devices and parameters, the practices in haemodynamic monitoring at the bedside. Methods. We conducted a Web-based survey in Swiss adult ICUs (2009-2010). The questionnaire explored the kind of monitoring used and how the fluid management was addressed. Results. Our survey included 71% of Swiss ICUs. Echocardiography (95%), pulmonary artery catheter (PAC: 85%), and transpulmonary thermodilution (TPTD) (82%) were the most commonly used. TPTD and PAC were frequently both available, although TPTD was the preferred technique. Echocardiography was widely available (95%) but seems to be rarely performed by intensivists themselves. Guidelines for the management of fluid infusion were available in 45% of ICUs. For the prediction of fluid responsiveness, intensivists rely preferentially on dynamic indices or echocardiographic parameters, but static parameters, such as central venous pressure or pulmonary artery occlusion pressure, were still used. Conclusions. In most Swiss ICUs, multiple haemodynamic monitoring devices are available, although TPTD is most commonly used. Despite the usefulness of echocardiography and its large availability, it is not widely performed by Swiss intensivists themselves. Regarding fluid management, several parameters are used without a clear consensus for the optimal method.

Ultrasound-based imaging in neurocritical care patients: a review of clinical applications

OBJECTIVE

To analyze the diagnostic, monitoring, and procedural applications of ultrasound (US) imaging in neurocritical care (NCC) patients.

METHOD

US imaging has been extensively validated in various subset of critically ill patients, but not specifically in the NCC population. We reviewed the clinical applications of US imaging for heart, vascular, brain, and lung evaluation and for possible procedural uses in NCC patients. Major neurosurgical books, journals, testimonials, authors' personal experience, and scientific databases were analyzed.

RESULTS

Cardiac US imaging provides accurate information at NCC arrival to stratify risk factors, including presence of atrial septal defect/patent formen ovale, abnormal ventricular function, or pericardial effusion, and to monitor cardiac anatomy and function during the NCC stay for guiding goal-directed therapy. Vascular US in NCC patients has three especially relevant indications: to screen anatomy and flow in extracranial supra-aortic arteries, to diagnose deep vein thrombosis, and to optimize the safety of central venous catheterization. Brain US has important clinical applications in the NCC, including transcranial Doppler and emerging techniques for cerebral blood flow evaluation with contrast-enhanced US imaging. Lung US, as demonstrated in other intensive care unit patients, provides accurate diagnosis of anatomical and functional abnormalities and enables diagnosis of pleural effusion, pneumothorax, lung consolidation, pulmonary abscess and interstitial-alveolar syndrome, and lung recruitment/derecruitment. US imaging can effectively guide percutaneous tracheostomy.

CONCLUSION

In conclusion, US imaging is an important diagnostic tool that provides real-time information at the bedside to stratify risk, monitor for complications, and guide invasive procedures in NCC patients.

[How should anesthesiologists perform ultrasound examinations? Diagnostic use of ultrasound in emergency and intensive care and medicine]

Ultrasound imaging has attained great significance as a tool for diagnostics in emergency and intensive care medicine. The major advantages of this technique are its instantaneous bedside availability and the possibility to perform repeatable examinations. These advantages are based on recent developments, such as portable ultrasound devices offering excellent imaging quality as well as a quick-start-function. Ultrasound imaging in critically ill patients is frequently performed under pressure of time depending on the current acute physical state. All standard examinations in echocardiography, vascular, abdominal and thoracic ultrasound scanning can be applied in these patients. Based on the clinical scenario the duration of examinations may vary from seconds during cardiopulmonary resuscitations to time-consuming repeated scanning. The transition from basic to subject-specific detailed examinations is flowing and has to be adjusted to local conditions. In the field of emergency and intensive care medicine the technique used is whole-body sonography. The goal is to classify the patient's present physical state and to define a targeted therapeutic approach. The characteristics of whole-body sonography are similar to the field of anesthesiology which is an interdisciplinary one. Currently, these characteristics deserve more attention in training in sonography.

Electrocardiographic ST-segment elevation myocardial infarction in critically ill patients: an observational cohort analysis

OBJECTIVE

To investigate the specificity of the electrocardiographic diagnosis of ST-segment elevation myocardial infarction in the critical care unit setting.

DESIGN

Retrospective observational cohort analysis.

SETTING

An 880-bed tertiary care teaching hospital with 120 intensive care unit beds.

PATIENTS

The population included medical, surgical, trauma, and neurosurgical intensive care unit patients.

INTERVENTIONS

Electrocardiograms were systematically collected to include all consecutive recordings over a 15-month period in which the interpretation software indicated ***ACUTE MI***. Patient demographics, markers of intensive care unit complexity, and hospital mortality were ascertained. The electrocardiograms were then further evaluated by a blinded, board-certified cardiologist for agreement or disagreement with the interpretation software. Serum troponin measurements obtained within 96 hrs of electrocardiogram acquisition were used to determine the likelihood of myocardial infarction.

MEASUREMENTS AND MAIN RESULTS

Over the 15-month study period, the interpretation software diagnosed ST-segment elevation myocardial infarction in 67 of 2243 intensive care unit patients (2.99%) who had an electrocardiogram performed. In the final study population of 46 cases with electrocardiographic ST-segment elevation myocardial infarction, 85% had peak troponin elevation<5 ng/mL, a strong suggestion against clinical ST-segment elevation myocardial infarction. The cardiologist agreed with the computer interpretation in 39% (18 of 46) of cases, but of those 18 patients, only six showed a significant rise in the troponin level. The cardiologist disagreed with the computer interpretation in 60.9% (28 of 46) of cases and of those, one patient had a marked elevation of the cardiac troponin.

CONCLUSIONS

ST-segment elevation myocardial infarction in the intensive care unit is a relatively common electrocardiographic reading both by standard interpretation software and by expert evaluation. In contrast to nonintensive care unit patients who present with chest pain, the electrocardiographic ST-segment elevation myocardial infarction diagnosis seems to be a nonspecific finding in the intensive care unit that is frequently the result of a variety of nonischemic processes. The vast majority of such patients do not have frank ST-segment elevation myocardial infarction.

Focused transthoracic echocardiography

Caring for critically ill patients requires rapid and accurate diagnosis followed by prompt interventions. The physical examination remains an important part of the assessment of such patients, but it has been shown to have a low sensitivity and specificity in judging left ventricular function and intravascular volume. Invasive hemodynamic monitoring has similarly been shown to have significant limitations and has failed to demonstrate a mortality benefit in several recent studies. In some studies, it has been shown to be harmful. Focused transthoracic echocardiography (TTE) has emerged as a noninvasive and portable imaging technique that is capable of providing rapid and accurate information about the heart at the bedside. It can be used to complement the physical examination and result in marked improvement in diagnostic accuracy. Focused TTE can be used as a screening and monitoring tool. Studies have shown that clinicians can be trained to determine left ventricular function, detect pericardial effusions, predict intravenous fluid responsiveness, and identify important valvular defects in a relatively short period. This article describes the indications for focused TTE, provides evidence that clinicians can be rapidly taught the technique, reviews how the focused studies affect management, and discusses the advantages and limitations of this tool.