Bedside ultrasonography in the ICU: part 1

[Bedside imaging]

Sonography, in particular echocardiography, is essential in the assessment of volume status and hemodynamics in critically ill patients. Examination of the left ventricle, in addition to assessing ventricular function, provides valuable information, including the "kissing papillary muscle sign," which may indicate fluid responsiveness. Examination of the right ventricle is also important because it is sensitive to both volume and pressure overload. Assessment of diastolic function and measurement of inferior vena cava width and variability provide clues to left and right ventricular preload, respectively. Measurement of stroke volume and cardiac output allows further assessment of hemodynamics and also permits determination of stroke volume variability.

A Review on the Impact of Bedside Echocardiography in Managing Critically Ill Children in the Pediatric Intensive Care Unit

Over the past three decades, a variety of non-invasive hemodynamic devices have been developed. However, none of the existing methods, such as transthoracic echocardiography, esophageal Doppler ultrasound, plethysmography, thoracic impedancemetry, or sublingual capnography, fully embody the ideal characteristics of reliability, reproducibility, rapid response, ease of use, comprehensive safety, affordability, and continuous monitoring capacity. Among these, echocardiography stands out as a particularly effective approach, meeting many of these criteria due to its widespread availability, relative ease of use, and critical role in detecting anatomical abnormalities and basic changes in myocardial function. It is frequently used in pediatric intensive care units to assess the structure and function of the heart muscle. The effectiveness of echocardiography in pediatric critical care is also constrained by the need for high-quality imaging and accurate interpretation. Currently, there is a notable lack of literature on the application of echocardiography in pediatric critical care. This study seeks to evaluate the existing scientific evidence regarding the effectiveness of echocardiography as a tool for monitoring hemodynamics in pediatric critical care settings.

The value of a dynamic echocardiographic approach to diastolic dysfunction in intensive care medicine

Diastolic dysfunction is an underestimated feature in the context of the critically ill setting and perioperative medicine. Advances in echocardiography, its noninvasive, safe and easy use, have allowed Doppler echocardiography to become a cornerstone for diagnosing diastolic dysfunction in clinical practice. The diagnosis of diastolic dysfunction and increased filling pressures is nevertheless complex. Using an echocardiographic assessment and the routine application of preload stress maneuvers during echocardiographic examination can help identify early stages of diastolic dysfunction leading to better management of patients at risk of acute heart decompensation in the perioperative period or during ICU stay.

Growth of targeted neonatal echocardiography in Chinese neonatal intensive care units: gaps in practice and training

To evaluate clinical practice, neonatologists' attitudes, and the extent of training and accreditation regarding targeted neonatal echocardiography (TnEcho) among Chinese neonatologists. A web-based questionnaire was emailed to 331 neonatologists across China who completed training in subspecialty neonatology. The survey covered various aspects of TnEcho, including the characteristics of clinical practice, attitudes towards its usefulness, and perceived barriers to implementation and training methods. Survey response rate was 68.0% (225/331). Seventy-nine (35.1%) respondents stated that TnEcho was utilized in their NICUs. Most respondents reported the use of echocardiography to evaluate hemodynamic significance of the patent ductus arteriosus (PDA, 94.9%). The eyeballing technique was most used to evaluate left (82.3%) and right (77.2%) ventricular function. Most respondents (87.3-96.2%) positively valued the role of TnEcho in providing timely and longitudinal hemodynamic information to guide cardiovascular care. Access to TnEcho was more likely in centers with on-site pediatric cardiology service (p = .003), larger bed capacity (p = .004), or level IV status (p = .003). Lack of experienced practitioners with echocardiography expertise (88.9%) and accredited training programs (85.8%) was perceived to be the major barrier to implementation. Of concern, most practitioners with TnEcho skills received training in an informal manner through workshops (60.8%) or self-directed learning (54.4%). Conclusions: The use of TnEcho for longitudinal evaluation of infants with hemodynamic instability is growing within Chinese NICUs. There is an urgent need to develop standardized training programs and accreditation for TnEcho which are adapted to the Chinese context.

Prediction of Fluid Responsiveness Using Combined End-Expiratory and End-Inspiratory Occlusion Tests in Cardiac Surgical Patients

End-expiratory occlusion (EEO) and end-inspiratory occlusion (EIO) tests have been successfully used to predict fluid responsiveness in various settings using calibrated pulse contour analysis and echocardiography. The aim of this study was to test if respiratory occlusion tests predicted fluid responsiveness reliably in cardiac surgical patients with protective ventilation. This single-centre, prospective study, included 57 ventilated patients after elective coronary artery bypass grafting who were indicated for fluid expansion. Baseline echocardiographic measurements were obtained and patients with significant cardiac pathology were excluded. Cardiac index (CI), stroke volume and stroke volume variation were recorded using uncalibrated pulse contour analysis at baseline, after performing EEO and EIO tests and after volume expansion (7 mL/kg of succinylated gelatin). Fluid responsiveness was defined as an increase in cardiac index by 15%. Neither EEO, EIO nor their combination predicted fluid responsiveness reliably in our study. After a combined EEO and EIO, a cut-off point for CI change of 16.7% predicted fluid responsiveness with a sensitivity of 61.8%, specificity of 69.6% and ROC AUC of 0.593. In elective cardiac surgical patients with protective ventilation, respiratory occlusion tests failed to predict fluid responsiveness using uncalibrated pulse contour analysis.

FoCUS cardiac ultrasound training for undergraduates based on current national guidelines: a prospective, controlled, single-center study on transferability

INTRODUCTION

In emergency and critical-care medicine, focused cardiac ultrasound (FoCUS) is indispensable for assessing a patient's cardiac status. The aim of this study was to establish and validate a peer-to-peer-supported ultrasound course for learning FoCUS-specific skills during undergraduate studies at a German university.

METHODS

A 1-day, 12 teaching units training course was developed for students in the clinical section of medical college, with content based on the current national guidelines. A total of 217 students participated in the study (97 in the course group and 120 in the control group). The course and the participants' subjective assessment of improved skills were evaluated using a questionnaire (7-point Likert scale; 7 = complete agreement and 1 = no agreement at all). Objective learning gains were assessed by tests before and after the course. These consisted of a test of figural intelligence (eight items) and a test of technical knowledge (13 items).

RESULTS

The course participants experienced significant improvement (P < 0.001) from before to after the course, with a large effect size of η²_part = 0.26. In addition, the course group had significantly better results (P < 0.001) than the control group in the post-test, with a medium to large effect size of η²_part = 0.14. No significant differences (P = 0.27) were detected in the test section on figural intelligence. The evaluations showed that the participants had a high degree of satisfaction with the course approach, teaching materials, and tutors. There was also a positive increase in their subjective assessment of their own skills, including areas such as technical knowledge, ultrasound anatomy, and performance of the examination.

CONCLUSION

The results of both the objective learning assessment and the subjective evaluations suggest that a FoCUS course originally intended for qualified physicians is equally suitable for students. With the development and provision of modern digital teaching media, even more students will be able to benefit from this approach in the future.

The Role of Echocardiography in Extracorporeal Membrane Oxygenation

PURPOSE OF REVIEW

Extracorporeal membrane oxygenation (ECMO) is increasingly used to temporarily support patients in severe circulatory and/or respiratory failure. Echocardiography is a core component of successful ECMO deployment. Herein, we review the role of echocardiography at different phases on extracorporeal support including candidate identification, cannulation, maintenance, complication vigilance, and decannulation.

RECENT FINDINGS

During cannulation, ultrasound is used to confirm intended vascular access and appropriate inflow cannula positioning. While on ECMO, echocardiographic evaluation of ventricular loading conditions and hemodynamics, cannula positioning, and surveillance for intracardiac or aortic thrombi is needed for complication mitigation. Echocardiography is crucial during all phases of ECMO use. Specific echocardiographic queries depend on the ECMO type, V-V, or V-A, and the specific cannula configuration strategy employed.

Improving hospital-based point-of-care ultrasound cleaning practices using targeted interventions: a pre-post study

BACKGROUND

Point-of-care ultrasound (POCUS) devices are becoming more widely used in healthcare and have the potential to act as fomites. The objective of this project was to study the thoroughness of cleaning of POCUS machines before and after a quality improvement initiative. We designed a mixed-methods, pre/post study which took place over the course of one year at a university-affiliated health center. Cleaning rates of four ultrasound machines used by hospital medicine and critical care medicine services were evaluated using fluorescent marking. Interventions targeted physicians' knowledge of best practices and improved access to cleaning supplies. Pre- and post-intervention cleaning rates were compared using a generalized linear model. The impact of the corona virus disease of 2019 (COVID-19) pandemic on baseline cleaning rates was also evaluated. Physicians' attitudes and knowledge of cleaning practices were evaluated via unpaired pre/post surveys.

RESULTS

There was significant improvement in thoroughness of cleaning following intervention (pre 0.62, SE 0.05; post 0.89, SE 0.07), p < 0.0001). There was no difference in baseline cleaning rates before (0.63, SE 0.09) and after (0.61, SE 0.1) the onset of the COVID-19 pandemic (p = 0.78). Post-intervention surveying found improved understanding of guideline-based cleaning practice, better performance on knowledge-based questions, and fewer reported barriers to machine cleaning.

CONCLUSION

Thoroughness of cleaning of POCUS machines can be improved with practical interventions that target knowledge and access to cleaning supplies.

Goal-directed Fluid Therapy Versus Conventional Fluid Therapy During Craniotomy and Clipping of Cerebral Aneurysm: A Prospective Randomized Controlled Trial

BACKGROUND

Fluid imbalance is common after aneurysmal subarachnoid hemorrhage and negatively impacts clinical outcomes. We compared intraoperative goal-directed fluid therapy (GDFT) using left ventricular outflow tract velocity time integral (LVOT-VTI) measured by transesophageal echocardiography with central venous pressure (CVP)-guided fluid therapy during aneurysm clipping in aneurysmal subarachnoid hemorrhage patients.

METHODS

Fifty adults scheduled for urgent craniotomy for aneurysm clipping were randomly allocated to 2 groups: group G (n=25) received GDFT guided by LVOT-VTI and group C (n=25) received CVP-guided fluid management. The primary outcome was intraoperative mean arterial pressure (MAP). Secondary outcomes included volume of fluid administered and several other intraoperative and postoperative variables, including neurological outcome at hospital discharge and at 30 and 90 days.

RESULTS

There was no difference in MAP between the 2 groups despite patients in group G receiving lower volumes of fluid compared with patients in group C (2503.6±534.3 vs. 3732.8±676.5 mL, respectively; P<0.0001). Heart rate and diastolic blood pressure were also comparable between groups, whereas systolic blood pressure was higher in group G than in group C at several intraoperative time points. Other intraoperative variables, including blood loss, urine output, and lactate levels were not different between the 2 groups. Postoperative variables, including creatinine, duration of postoperative mechanical ventilation, length of intensive care unit and hospital stay, and incidence of acute kidney injury, pneumonitis, and vasospasm were also comparable between groups. There was no difference in neurological outcome at hospital discharge (modified Rankin scale) and at 30 and 90 days (Extended Glasgow Outcome Scale) between the 2 groups.

CONCLUSION

Compared with CVP-guided fluid therapy, transesophageal echocardiography-guided GDFT maintains MAP with lower volumes of intravenous fluid in patients undergoing clipping of intracranial aneurysms with no adverse impact on postoperative complications.

Point-of-Care Echocardiography: A Useful Tool for Assessing Complex Arrhythmias in the Pediatric Intensive Care Unit

OBJECTIVE

To demonstrate that the analysis of the atrioventricular, intraventricular, and interventricular asynchrony by point-of-care ultrasound (POCUS) could be an alternative tool for assessing complex arrhythmias in pediatric patients with congenital heart diseases, mainly when an epicardial register or electrophysiology study is not available.

DESIGN

Descriptive, retrospective case series study.

SETTING

The pediatric intensive care unit of a university-affiliated tertiary hospital in Spain.

PATIENTS

The authors included 12 patients with congenital heart disease younger than 18 years admitted to the authors' pediatric intensive care unit (PICU) from January 2018 to December 2019, with complex arrhythmias after surgery, managed by performing a bedside echocardiography when an electrophysiology test or epicardial auriculogram was unavailable.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

The authors included a total of 14 complex arrhythmias in 12 postsurgical patients in whom a comprehensive transthoracic electrocardiogram was not conclusive. The presence of atrioventricular, intraventricular, or interventricular asynchrony was assessed in standard echo views by performing M-mode and Doppler mitral inflow analysis, checking the heart motion. The final POCUS diagnoses were atrial flutter (n = 5), postsurgical atrioventricular block (n = 4), asynchrony induced by pacemaker (n = 2), junctional ectopic tachycardia (n = 1), nodal rhythm plus ventricular extrasystole (n = 1), and supraventricular tachycardia (n = 1). In all patients, regardless of the type of arrhythmia, detecting motion asynchrony was crucial for making the correct diagnosis. Offline cardiologist analysis of the POCUS scans showed full agreement.

CONCLUSIONS

POCUS is a useful tool for initial diagnosis and management of complex arrhythmias in the PICU, mainly when epicardial auriculogram or electrophysiology studies are unavailable.

[Sonography in intensive care and emergency medicine : A new training concept]

Structured sonography training in internal medicine intensive care and emergency medicine (SIN) comprises two levels and was proposed by three national societies in Germany (DGIIN, DGK and DEGUM). The curriculum consists of a basic level (SIN-I) and an expert level (SIN-II) which are consecutive levels teaching both theoretical and hands-on skills using a symptom-based approach. Competency is assessed using written, oral and practical structured assessments at the end of each level. The goal is to implement national and international recommendations regarding the use of point-of-care ultrasound into clinical practice.

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.

Physicians' abilities to obtain and interpret focused cardiac ultrasound images from critically ill patients after a 2-day training course

Background

This study aimed to determine whether a focused 2-day cardiac ultrasound training course could enable physicians to obtain and interpret focused cardiac ultrasound (FCU) images from critically ill patients.

Methods

We retrospectively reviewed the FCU images submitted by the physicians who attended a 2-day FCU training courses. Three experienced trainers reviewed the images separately. They determined whether the images were assessable and scored the images on an 8-point scale. They also decided whether the physicians provided correct responses for visual estimations of the left ventricular ejection fraction (LVEF) and right ventricle (RV) dilatation and septal motion.

Results

Among the 327 physicians, 291 obtained images that were considered assessable (89%). The scores for parasternal short-axis view were lower than those obtained for other transthoracic echocardiographic views, p < 0.001. More physicians provided incorrect appraisals of LVEF than of RV dilatation and septal motion (19.9% vs. 3.1%, p < 0.001). The percentages of incorrect answers by LVEF category were as follows: 34.8% on images of LVEF < 30, 24.7% on images of LVEF 30–54, and 16.4% on images of LVEF ≥55%, p < 0.001. A logistic regression analysis showed that patients with abnormal LVEF were associated with physicians’ incorrect assessment of LVEF, with an odds ratio of 1.923 (95% confidence interval (CI):1.071–3.456, p = 0.029).

Conclusions

A large proportion of physicians could obtain and interpret FCU images from critically ill patients after a 2-day training course. However, they still scored low on the parasternal short-axis view and were more likely to make an incorrect assessment of LVEF in patients with abnormal left ventricular systolic function.

Ultrasound Guidance for Central Venous Access: Current Evidence and Clinical Recommendations

Ultrasound-guided central line placement has been shown to decrease the number of needle puncture attempts, complication, and failure rates. In order to obtain successful central access, it is important to have adequate cognitive knowledge, workflow understanding, and manual dexterity to safely execute this invasive procedure. The operator should also be familiar with the anatomical variations, equipment operations, and potential complications and their prevention. In this article, we present a detailed review of ultrasound-guided central venous access. It includes a description of anatomy, operative technique, equipment operation, and techniques for specific situations. We describe the use of ultrasound guidance to avoid and identify various complications associated with this procedure. We have also reviewed recent recommendations and guidelines for the use of ultrasound for central venous access and the current evidence pertaining to the recommendations for the expected level of training, methodology, and metrics for establishing competency.

Diagnostic Accuracy of Critical Care Transesophageal Echocardiography vs Cardiology-Led Echocardiography in ICU Patients

BACKGROUND

Critical care transesophageal echocardiography (ccTEE) performed by intensivists is increasingly used to investigate cardiorespiratory failure in the ICU. Validation of the accuracy of TEE in the hands of intensivists remains largely unknown. The goal of this study was to characterize the diagnostic accuracy of ccTEE.

METHODS

This study was a two-center, retrospective comparison between TEE studies performed and interpreted by intensivists and cardiology-led TEE or transthoracic echocardiography (TTE) performed and/or interpreted by cardiologists. The study period was December 2012 to December 2016 for all consecutive ICU patients who received an initial ccTEE and either a cardiology TEE or TTE within 72 h. Using the cardiology-conducted examination as the gold standard, we reported sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy of ccTEE.

RESULTS

Comparisons between ccTEE and cardiology TEE/TTE performed yielded 56 patients (five ccTEE vs cardiology TEE and 51 ccTEE vs cardiology TTE). The comparison between ccTEE and cardiology TEE showed 100% sensitivity, specificity, PPV, NPV, and accuracy for the primary diagnosis and other major findings. For the combined ccTEE and cardiology TEE/TTE comparison, there was a high sensitivity/specificity/PPV/NPV/accuracy for the primary diagnosis (90%-100% range), as well as other major diagnoses (88%-100% range).

CONCLUSIONS

This study showed that ccTEE has a high sensitivity, specificity, PPV, NPV, and accuracy compared with the gold standard cardiology TEE or TTEs in critically ill patients, when performed by advanced echocardiogram-trained/experienced intensivists.

Solid, Cystic, and Tubular: Novice Ultrasound Skills Training Using a Versatile, Affordable Practice Model

OBJECTIVE

In spite of the recognized benefits of ultrasound, many physicians have little experience with using ultrasound to perform procedures. Many medical schools and residency programs lack a formal ultrasound training curriculum. We describe an affordable ultrasound training curriculum and versatile, inexpensive practice model.

DESIGN

Participants underwent a didactic session to teach the theory required to perform ultrasound-guided procedures. Motor skills were taught using a practice model incorporating analogs of common anatomic and pathologic structures into an opacified gelatin substrate.

SETTING

The Marcia and Eugene Applebaum Simulation Learning Institute, Beaumont Hospital, Royal Oak, MI; a private nonprofit tertiary care hospital associated with the OUWB School of Medicine, Rochester, MI.

PARTICIPANTS

The model was tested in a cohort of 50 medical students and general surgery residents.

RESULTS

The gelatin model can be constructed for $1.03 per learner. The solid, cystic, and vascular structural analogs were readily identifiable on ultrasound and easily differentiated based on their echotextures. Eighty-four percent of participants successfully aspirated the cystic structure, 88% successfully biopsied a portion of the solid structure, and 76% successfully cannulated the tubular structure. Overall, 82% of participants achieved a passing score for the exercise based on a validated Objective Structured Assessment of Technical Skill instrument. There were no significant differences between the medical students and residents.

CONCLUSION

This model can be used to teach basic ultrasound skills such as aspiration, biopsy, and vessel cannulation, providing a foundation for the use of ultrasound in a broad range of clinical procedures, as well as providing practice opportunities for medical students and residents to gain increased ultrasound competency and confidence.

Ultrasound Training in Surgical Critical Care Fellowship: A Survey of Program Directors

OBJECTIVE

Surgical critical care (SCC) fellows are expected to receive training in critical care ultrasound (CCUS) but training is sporadic and there is no standardized curriculum to guide educators. Previous studies show wide variation in CCUS training during fellowship across specialties but SCC has been underrepresented. This study was performed to assess SCC program directors' views regarding CCUS during fellowship training.

DESIGN

Adult SCC program directors were surveyed regarding the role of CCUS in fellowship training. This survey assessed how CCUS training was performed, perceived barriers to education, and importance of specific studies. Survey responses were measured using a Likert scale ranging from 5 (strongly agree) to 1 (strongly disagree).

SETTING

Web-based survey.

PARTICIPANTS

Adult Surgical Critical Care Fellowship Program Directors.

RESULTS

A total 67 of 108 (62%) SCC program directors responded to the survey. Over 75% felt that CCUS during training should be a priority. Fifteen (24.6%) programs required a specific number of ultrasounds to be performed. Five programs (7.5%) provided no CCUS training at all. Over 75% felt that training in FAST, transthoracic echocardiography, inferior vena cava assessment, and US for procedures (line placement, thoracentesis, and paracentesis) were either important or very important but experience in transesophageal echocardiography, assessment for deep vein thrombosis, and pulmonary US were not important. Lack of time (63.8%) and trained faculty (51.2%) were the most cited barriers to training.

CONCLUSIONS

There is a wide variation in how CCUS training is performed during SCC fellowship. SCC programs will need trained faculty, appropriate time allocation, and implementation of a standardized curriculum to provide consistent and high-quality CCUS education during fellowship.

[Recommendations for education in ultrasound in medical intensive care and emergency medicine: position paper of DGIIN, DEGUM and DGK]

Point-of-care ultrasound in acute care medicine is a prerequisite for diagnosis and therapy monitoring of critically ill patients. There is currently no uniform education strategy for medical intensive care and emergency medicine. As part of the basic level, the trainee takes theoretical and clinical training covering abdominal and thoracic ultrasonography and focused cardiovascular ultrasound. In a second step, special knowledge and skills can be acquired at an expert level. This two-stage concept is intended to guarantee quality assurance in ultrasound education in medical intensive care and emergency medicine.

Evaluation of the placement and maintenance of central venous jugular catheters in critically ill dogs and cats

OBJECTIVE

To describe problems noted during central venous jugular catheter (CVJC) placement, conditions associated with unsuccessful catheterization, and CVJC maintenance complications.

DESIGN

Prospective observational study from September 2014 to September 2015.

SETTING

University veterinary teaching hospital.

ANIMALS

Twenty-seven dogs and 20 cats hospitalized in a veterinary ICU. Patients were excluded if previously hospitalized with a CVJC or lacked sufficient data.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Ninety-one percent of indwelling CVJCs were placed successfully (43/47, 95% CI: 80%, 98%). Procedural-related difficulties that resulted in the inability to place a CVJC totaled 18/63 (28.6%, 95% CI: 18%, 41%) and included the inability to puncture the vessel (10), hematoma (6), malposition (1), and dislodgement (1). Procedural complications occurred in 24/47 patients (51%, 95% CI: 36%, 66%) and included cardiac dysrhythmias (13), hematoma (6), CVJC placement failure (4), and malposition (1). Risk factors associated with multiple catheterization attempts included increased age (7.5 years [± 4.2] vs 10.6 years [± 4.1], P = 0.04), smaller size (8.0 kg [0.6-51.9 kg] vs 4.4 kg [2.6-6.8 kg], P < 0.01) and thinner body condition score (median 5/9 [2/9-9/9] vs 4/9 [2/9-7/9], P = 0.04). The risk factor associated with dysrhythmias was smaller patient size (6.8 kg [2.6-51.9 kg] vs 4.8 kg [0.6-29.5 kg], P = 0.04). Eighteen indwelling complications occurred in 14 patients and included mechanical obstruction (7), skin irritation (6), malposition (4), and inflammation (1). Risk factors for indwelling complications included longer dwell time (5 days [2-30] vs 3 days [1-10], P < 0.01) and the administration of an irritant medication (P = 0.02).

CONCLUSIONS

Complications were documented in the placement and maintenance of CVJCs in critically ill patients with a low incidence of life-threatening sequelae. Risk factors associated with both unsuccessful CVJC placement and indwelling CVJC complications were identified.

Ultrasound in acute internal medicine; time to set a European standard

Nowadays point-of-care ultrasound (POCUS) is considered indispensable for critical care and emergency physicians. POCUS is a noninvasive tool, can be done at the bedside, leads to instant diagnostic information and is safe in terms of radiation. POCUS could also be very suitable for internists in the field of acute internal medicine. There are differences between European internists in the use of POCUS from no use at all to more outlined educational programs. In literature there are examples of comprehensive POCUS guidelines which could serve as an example for the European Federation of Internal Medicine (EFIM). In this review some aspects of POCUS are highlighted and the authors encourage EFIM to set European standards for this important development.

POCUS in perioperative medicine: a North American perspective

Ultrasound (US) performed at the point of care has found fertile ground in perioperative medicine. In the hands of anesthesiologists, transesophageal echocardiography (TEE) has become established as a powerful diagnostic and monitoring tool in the perioperative care of cardiac and non-cardiac patients. A number of point-of-care US (POCUS) applications are relevant to perioperative care, including airway, cardiac, lung and gastric US. Although guidelines exist to define the scope of practice for basic and advanced TEE, there remains a lack of such guidelines for perioperative point-of-care ultrasound (POCUS), despite a number of recent calls for action in the academic anesthesia community. POCUS training has been integrated into anesthesia residency curricula in Canada and the United States of America (USA). However, a nation-wide curriculum is still lacking. Many limitations to the development of perioperative POCUS curricula exist, including the need to define the scope of practice and design integrated longitudinal learning approaches. The main anesthesiologist societies in both the USA and Canada are promoting the development of guidelines and have introduced POCUS courses into their national conferences. Although bedside US imaging has been integrated into the curricula of many medical schools in North America, the need for specific national guidelines for the training and practice of POCUS in the perioperative setting by anesthesiologists is crucial to the further development of POCUS in perioperative medicine.

Using M-mode ultrasonography to assess diaphragm dysfunction and predict the success of mechanical ventilation weaning in elderly patients

Background

Ultrasonography (US) is a non-invasive and commonly available bedside diagnostic tool. The aim of this study was to assess the utility of M-mode US on ventilator weaning outcomes in elderly patients.

Methods

This was a single center, prospective, observational study in patients aged 80 years or older who were in the medical intensive care unit, had undergone mechanical ventilation for >48 hours, and met the criteria for a spontaneous breathing trial (SBT). For 30 minutes at the start of SBT, each hemi-diaphragmatic movement and the velocity of contraction were evaluated by M-mode US. The the area under the receiver operating characteristic curve (AUROC) was calculated to determine the ability for measured variables to predict successful ventilator weaning.

Results

Forty patients were enrolled and assessed, grouped by those who had US-diagnosed diaphragm dysfunction (DD; 30/40; 75%) and those who did not (10/40; 25%). Patients with DD had a significantly longer total mechanical ventilation duration (536.4±377.05 vs. 250±109.02 hours, P=0.02) and weaning time (425.9±268.31 vs. 216.0±134.22 hours, P=0.002) than patients without DD. Patients with DD also had a higher incidence of weaning failure than patients without DD (24/30 vs. 4/10, P=0.017). Analysis of the receiver operating characteristic (ROC) curve (ROC) curve showed that the optimal cut-off values to predict weaning success were >10.7 mm for the right diaphragmatic movement, and >21.32 mm/s for the right diaphragmatic velocity of contraction; AUROC were 0.839 (95% CI, 0.689-0.936) and 0.833 (95% CI, 0.682-0.932), respectively. The sensitivity, specificity, positive and negative likelihood ratios for predicting weaning success were 83.33% vs. 66.67%, 75.00% vs. 92.86%, 3.33 vs. 9.33, and 0.22 vs. 0.36, for right diaphragmatic movement and diaphragmatic contraction velocity, respectively.

Conclusions

When assessed by M-mode US, DD appeared to be common in ventilated patients aged 80 years or older and was associated with a higher incidence of weaning failure. Larger right diaphragmatic movements or faster right diaphragmatic contraction velocity appeared to be good predictors of mechanical ventilation weaning success in elderly patients.

A System for Continuous Estimating and Monitoring Cardiac Output via Arterial Waveform Analysis

BACKGROUND

Cardiac output (CO) is the total volume of blood pumped by the heart per minute and is a function of heart rate and stroke volume. CO is one of the most important parameters for monitoring cardiac function, estimating global oxygen delivery and understanding the causes of high blood pressure. Hence, measuring CO has always been a matter of interest to researchers and clinicians. Several methods have been developed for this purpose, but a majority of them are either invasive, too expensive or need special expertise and experience. Besides, they are not usually risk free and have consequences.

OBJECTIVE

Here, a semi-invasive system was designed and developed for continuous CO measurement via analyzing and processing arterial pulse waves.

RESULTS

Quantitative evaluation of developed CO estimation system was performed using 7 signals. It showed that it has an acceptable average error of (6.5%) in estimating CO. In addition, this system has the ability to consistently estimate this parameter and to provide a CO versus time curve that assists in tracking changes of CO. Moreover, the system provides such curve for systolic blood pressure, diastolic blood pressure, average blood pressure, heart rate and stroke volume.

CONCLUSION

Evaluation of the results showed that the developed system is capable of accurately estimating CO. The curves which the system provides for important parameters may be valuable in monitoring hemodynamic status of high-risk surgical patients and critically ill patients in Intensive Care Units (ICU). Therefore, it could be a suitable system for monitoring hemodynamic status of critically ill patients.

Basics of Functional Echocardiography in Children and Neonates

Functional echocardiography has become an invaluable tool in the pediatric and neonatal intensive care unit. "Point-of-care," "target," or "focus" echocardiography allows bedside cardiac ultrasound evaluation of the hemodynamic status of the patient, helps in directing treatment, thus improves patients care. In order to be able to perform functional echocardiography, it is essential to understand the principles of ultrasound, to know the echocardiographic equipment and settings necessary to acquire the images. This article focuses therefore on the basics of cardiac ultrasound. It is meant to give an overview of two-dimensional echocardiographic views, M-mode imaging and Doppler echocardiography for neonatologists and pediatric intensivists. It is richly illustrated for better understanding with some examples of clinical applications of functional echocardiography in the intensive care setting.

Bedside echocardiography in critically ill patients

The echocardiography has become a vital tool in the diagnosis of critically ill patients. The use of echocardiography by intensivists has been increasing since the 1990’s. This tool has become a common procedure for the cardiovascular assessment of critically ill patients, especially because it is non-invasive and can be applied in fast and guided manner at the bedside. Physicians with basic training in echocardiography, both from intensive care unit or emergency department, can assess the left ventricle function properly with good accuracy compared with assessment made by cardiologists. The change of treatment approach based on echocardiographic findings is commonly seen after examination of unstable patient. This brief review focuses on growing importance of echocardiography as an useful tool for management of critically ill patients in the intensive care setting along with the cardiac output assessment using this resource.

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.

Surgical wound assessment by sonography in the prediction of surgical wound infections

BACKGROUND

Surgical site infections (SSIs) are important sources of morbidity, prolonged hospital stays, and readmissions, so they have become a major economic burden. We hypothesized that surgical wound assessment by sonography (SWATS) used at the bedside would detect wound fluid collections and that the presence of such collections would predict SSI better than standard clinical examination. If so, SWATS might be used to indicate early intervention that could prevent SSI morbidity.

METHODS

A prospective, single-institution observational study was conducted on adult inpatients following open abdominal surgery for trauma, gastrointestinal pathology, or biliary pathology at high risk (>5%) for SSI using traditional wound classifications. After informed consent was obtained, SWATS was performed using a smartphone-based ultrasound system on postoperative Day 2 to 4 and again before discharge or at postoperative Day 30, whichever came first. Primary treating physicians delivered standard wound care and were blinded to SWATS. SSI was diagnosed if treatment was implemented for suspected or documented wound infection by the treating physician. Results were analyzed by χ test and two-sample pooled variance t test where appropriate, with significance set at p < 0.05.

RESULTS

Forty-nine patients were studied. Nineteen patients had peri-incisional fluid collections found by SWATS. Eight of these patients went on to develop an SSI. SSI was significantly associated with the presence of fluid collections on SWATS (p = 0.009). SWATS had a sensitivity of 72.7% (0.43-0.92), a specificity of 71.1% (0.62-0.77), a positive predictive value of 42.1% (0.25-0.53), and a negative predictive value of 90.0% (0.79-0.97).

CONCLUSION

SWATS has a high negative predictive value that may allow it be an effective screening tool for developing SSI in high-risk surgical wounds. SWATS has the potential to be a useful and cost-effective adjunct to the clinician by objectively suggesting need for early therapy. Further study with larger sample sizes and randomized, SWATS-based interventions are required to validate this small study and determine its place in clinical care.

LEVEL OF EVIDENCE

Diagnostic study, level IV.

Incremental value of thoracic ultrasound in intensive care units: Indications, uses, and applications

Emergency physicians are required to care for unstable patients with life-threatening conditions, and thus must make decisions that are both quick and precise about unclear clinical situations. There is increasing consensus in favor of using ultrasound as a real-time bedside clinical tool for clinicians in emergency settings alongside the irreplaceable use of historical and physical examinations. B-mode sonography is an old technology that was first proposed for medical applications more than 50 years ago. Its application in the diagnosis of thoracic diseases has always been considered limited, due to the presence of air in the lung and the presence of the bones of the thoracic cage, which prevent the progression of the ultrasound beam. However, the close relationship between air and water in the lungs causes a variety of artifacts on ultrasounds. At the bedside, thoracic ultrasound is based primarily on the analysis of these artifacts, with the aim of improving accuracy and safety in the diagnosis and therapy of the various varieties of pulmonary pathologic diseases which are predominantly “water-rich” or “air-rich”. The indications, contraindications, advantages, disadvantages, and techniques of thoracic ultrasound and its related procedures are analyzed in the present review.

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.

The introduction of basic critical care echocardiography reduces the use of diagnostic echocardiography in the intensive care unit

BACKGROUND

Basic critical care echocardiography (CCE) is routinely used by intensive care unit (ICU) providers to rapidly address key hemodynamic questions for the critically ill. By comparison, diagnostic echocardiography (DE) uses a comprehensive examination with more traditional workflow and sophisticated techniques. Despite these differences, both are frequently used to answer similar questions in ICU. This overlap raises questions of duplicate testing and redundancy of hospital resources. We therefore evaluated the effect of the introduction of basic CCE over the use of DE in Victoria Hospital, a tertiary care ICU in London Ontario, Canada.

METHODS

The monthly mean ratios of basic CCE and DE studies to patient care days (PCD) were plotted and general linear models were used to test for trends over time. Student t test was used to compare the mean DE/PCD before and after the introduction of basic CCE. The ratio of management actions for basic CCE studies was described. Outcome measures were compared using Pearson χ(2) test of association or the Wilcoxon rank sum test.

RESULTS

Over the 2-year study period, 1264 basic CCE studies were performed. Over this time, the ratio of CCE/PCD increased significantly (P<.001), whereas the ratio of DE/PCD decreased significantly (P=.004). When comparing the pre- and post-CCE periods, the mean DE/PCD decreased significantly from 5.27% to 4.51% (P=.01). There was no adverse change in ICU outcomes before and after the introduction of basic CCE. Mortality rates (pre- and post-CCE) were 23.69% and 24.61% (P=.48); median length of stay was 4.18 and 3.53 days (P<.001); and ventilated patient day rate was 64.96% and 64.93% (P>.9). There was a significant increase in vasoactive/inotropic drugs from a 20.47% vasoactive/inotropic drug/patient day rate to 21.99% (P<.001). Of all basic CCE studies, 61% led to a specific management action, including ordering a DE in 10.7% of cases.

CONCLUSION

In a hospital with a significant increase in basic CCE use, an associated significant decrease in DE use was observed with no increase in adverse outcomes. The significant increase in basic CCE use resulted in a change of management in most cases including the request for DE in a minority of cases.

Hyperdynamic left ventricular ejection fraction in the intensive care unit

Introduction

Limited information exists on the etiology, prevalence, and significance of hyperdynamic left ventricular ejection fraction (HDLVEF) in the intensive care unit (ICU). Our aim in the present study was to compare characteristics and outcomes of patients with HDLVEF with those of patients with normal left ventricular ejection fraction in the ICU using a large, public, deidentified critical care database.

Methods

We conducted a longitudinal, single-center, retrospective cohort study of adult patients who underwent echocardiography during a medical or surgical ICU admission at the Beth Israel Deaconess Medical Center using the Multiparameter Intelligent Monitoring in Intensive Care II database. The final cohort had 2867 patients, of whom 324 had HDLVEF, defined as an ejection fraction >70 %. Patients with an ejection fraction <55 % were excluded.

Results

Compared with critically ill patients with normal left ventricular ejection fraction, the finding of HDLVEF in critically ill patients was associated with female sex, increased age, and the diagnoses of hypertension and cancer. Patients with HDLVEF had increased 28-day mortality compared with those with normal ejection fraction in multivariate logistic regression analysis adjusted for age, sex, Sequential Organ Failure Assessment score, Elixhauser score for comorbidities, vasopressor use, and mechanical ventilation use (odds ratio 1.38, 95 % confidence interval 1.039–1.842, p =0.02).

Conclusions

The presence of HDLVEF portended increased 28-day mortality, and may be helpful as a gravity marker for prognosis in patients admitted to the ICU. Further research is warranted to gain a better understanding of how these patients respond to common interventions in the ICU and to determine if pharmacologic modulation of HDLVEF improves outcomes.

Implementation and assessment of a curriculum for bedside ultrasound training

OBJECTIVES

This study assessed a curriculum for bedside ultrasound (US) and compared outcomes from 2 common training pathways.

METHODS

The program consisted of e-learning paired with expert-led hands-on training administered to pulmonary/critical care and cardiology fellows with no prior formal training in bedside US. This "simulation-based learner" group completed a survey of attitudes and confidence before and after training, and knowledge and skills were assessed after training. The surveys and scores of the simulation-based learners were compared to the scores of "experts," who were US-trained emergency physicians, and "apprentice learners," who were intensivist physicians informally trained in bedside US on the job during fellowships.

RESULTS

There was a significant difference in the self-reported level of prior training between the groups (simulation-based learners, 2.8; apprentice learners, 3.7; experts, 4.1, on a scale of 1-5 [P= .02]) but no difference in the interest level or perceived importance of bedside US. The study curriculum was successful, as shown by scores that exceeded the comparison groups in the cardiac and pulmonary courses (cardiac: simulation-based learners, 80%; apprentice learners, 73%; experts, 62% [P= .001]; pulmonary: 84%, 75%, and 72%, respectively [P =.02]). The simulation-based learners gained confidence in skills, whereas the comparison groups lost confidence after testing (P < .005); however, the simulation-based learners gained confidence in US subject areas that were not taught (abdomen [P <.002] and miscellaneous [P =.005]).

CONCLUSIONS

The simulation-based learner curriculum resulted in comparable or greater knowledge and confidence in each area of US versus the comparison groups. Findings of overgeneralization of confidence highlight the importance of quality assurance and supervision in bedside US training programs.

Diaphragm ultrasound as indicator of respiratory effort in critically ill patients undergoing assisted mechanical ventilation: a pilot clinical study

Introduction

Pressure-support ventilation, is widely used in critically ill patients; however, the relative contribution of patient’s effort during assisted breathing is difficult to measure in clinical conditions. Aim of the present study was to evaluate the performance of ultrasonographic indices of diaphragm contractile activity (respiratory excursion and thickening) in comparison to traditional indices of inspiratory muscle effort during assisted mechanical ventilation.

Method

Consecutive patients admitted to the ICU after major elective surgery who met criteria for a spontaneous breathing trial with pressure support ventilation were enrolled. Patients with airflow obstruction or after thoracic/gastric/esophageal surgery were excluded. Variable levels of inspiratory muscle effort were achieved by delivery of different levels of ventilatory assistance by random application of pressure support (0, 5 and 15 cmH₂O). The right hemidiaphragm was evaluated by B- and M-mode ultrasonography to record respiratory excursion and thickening. Airway, gastric and oesophageal pressures, and airflow were recorded to calculate indices of respiratory effort (diaphragm and esophageal pressure–time product).

Results

25 patients were enrolled. With increasing levels of pressure support, parallel reductions were found between diaphragm thickening and both diaphragm and esophageal pressure–time product (respectively, R = 0.701, p < 0.001 and R = 0.801, p < 0.001) during tidal breathing. No correlation was found between either diaphragm or esophageal pressure–time product and diaphragm excursion (respectively, R = −0.081, p = 0.506 and R = 0.003, p = 0.981), nor was diaphragm excursion correlated to diaphragm thickening (R = 0.093, p = 0.450) during tidal breathing.

Conclusions

In patients undergoing in assisted mechanical ventilation, diaphragm thickening is a reliable indicator of respiratory effort, whereas diaphragm excursion should not be used to quantitatively assess diaphragm contractile activity.

Electronic supplementary material

The online version of this article (doi:10.1186/s13054-015-0894-9) contains supplementary material, which is available to authorized users.

Useful but not used: pediatric critical care physician views on bedside ultrasound

OBJECTIVE

The purpose of this study was to assess the learning needs of pediatric critical care (PCC) physicians in bedside ultrasound (BUS) use.

METHODS

This was a survey-based study conducted at an academic center with a PCC fellowship program. We surveyed PCC fellows and faculty to elicit their views on BUS and asked them about the frequency of use, their perception of the clinical utility, and their level of confidence in performing different BUS applications.

RESULTS

There was no statistical difference in the self-reported use of BUS applications in the faculty and fellows, except for cardiac arrest, which 66.7% of the faculty used but none of the fellows did (P < 0.05). There were no statistically significant differences between perceived usefulness and confidence in the performance of BUS applications between the fellows and faculty. The largest gaps between perceived usefulness and confidence in performing BUS applications were for left ventricle ejection fraction (Δ = 2.72), inferior vena cava collapse (Δ = 2.67), pulmonary edema (Δ = 2.22), and pneumothorax (Δ = 2.11).

CONCLUSIONS

Pediatric critical care providers report limited confidence in several applications that they perceive as useful and are therefore likely motivated to learn BUS applications. Concentrating curricula on those applications with the greatest differences between usefulness and confidence and building on the confidence of those applications the PCC providers are already using will serve to expand availability and increase use of this high-impact technology.

Development and preliminary assessment of a critical care ultrasound course in an adult pulmonary and critical care fellowship program

BACKGROUND

The focused ultrasound examination has become increasingly recognized as a safe and valuable diagnostic tool for the bedside assessment of the critically ill patient. We implemented a dedicated on-site critical care ultrasonography curriculum with the goal of developing a model for teaching ultrasound skills to pulmonary and critical care medicine fellows.

METHODS

The program was comprised of blended didactic and bedside sessions in the following topic domains: fundamentals; vascular access and diagnosis; and abdominal, thoracic, and cardiac ultrasonography. Formal knowledge and image acquisition assessments were performed before and after the program to assess success in meeting predefined learning objectives. Participants completed surveys (on Likert scale 1-5) before and after the program to assess their confidence in ultrasonography knowledge and skills as well as their perception as to training effectiveness.

RESULTS

The preintervention knowledge and bedside image acquisition scores were 71 and 32%, respectively. The global preintervention score was 51%. All postintervention measures demonstrated significant improvement: 89% (P < 0.01), 86% (P < 0.0001), and 87% (P < 0.0001). Preintervention participant confidence in their ultrasound knowledge and skill was 2.9/5, which improved to 4.3/5 (P = 0.007) after intervention. Participants rated the curriculum as meeting course objectives at a mean of 4.8/5.

CONCLUSIONS

At one academic medical center, the knowledge of eight adult pulmonary and critical care fellowship trainees regarding critical care ultrasound was high at baseline; however, bedside image acquisition skills were poor. A dedicated 6-week educational intervention resulted in highly significant improvements in subject knowledge and image acquisition skills. These preliminary results warrant validation studies at other medical centers.

Bedside ultrasound training using web-based e-learning and simulation early in the curriculum of residents

BACKGROUND

Focused bedside ultrasound is rapidly becoming a standard of care to decrease the risks of complications related to invasive procedures. The purpose of this study was to assess whether adding to the curriculum of junior residents an educational intervention combining web-based e-learning and hands-on training would improve the residents' proficiency in different clinical applications of bedside ultrasound as compared to using the traditional apprenticeship teaching method alone.

METHODS

Junior residents (n = 39) were provided with two educational interventions (vascular and pleural ultrasound). Each intervention consisted of a combination of web-based e-learning and bedside hands-on training. Senior residents (n = 15) were the traditionally trained group and were not provided with the educational interventions.

RESULTS

After the educational intervention, performance of the junior residents on the practical tests was superior to that of the senior residents. This was true for the vascular assessment (94% ± 5% vs. 68% ± 15%, unpaired student t test: p < 0.0001, mean difference: 26 (95% CI: 20 to 31)) and even more significant for the pleural assessment (92% ± 9% vs. 57% ± 25%, unpaired student t test: p < 0.0001, mean difference: 35 (95% CI: 23 to 44)). The junior residents also had a significantly higher success rate in performing ultrasound-guided needle insertion compared to the senior residents for both the transverse (95% vs. 60%, Fisher's exact test p = 0.0048) and longitudinal views (100% vs. 73%, Fisher's exact test p = 0.0055).

CONCLUSIONS

Our study demonstrated that a structured curriculum combining web-based education, hands-on training, and simulation integrated early in the training of the junior residents can lead to better proficiency in performing ultrasound-guided techniques compared to the traditional apprenticeship model.

A practical approach to goal-directed echocardiography in the critical care setting

Urgent cardiac ultrasound examination in the critical care setting is clinically useful. Application of goal-directed echocardiography in this setting is quite distinct from typical exploratory diagnostic comprehensive echocardiography, because the urgent critical care setting mandates a goal-directed approach. Goal-directed echocardiography most frequently aims to rapidly identify and differentiate the cause(s) of hemodynamic instability and/or the cause(s) of acute respiratory failure. Accordingly, this paper highlights 1) indications, 2) an easily memorized differential diagnostic framework for goal-directed echocardiography, 3) clinical questions that must be asked and answered, 4) practical issues to allow optimal image capture, 5) primary echocardiographic views, 6) key issues addressed in each view, and 7) interpretation of findings within the differential diagnostic framework. The most frequent indications for goal-directed echocardiography include 1) the spectrum of hemodynamic instability, shock, and pulseless electrical activity arrest and 2) acute respiratory failure. The differential diagnostic categories for hemodynamic instability can be remembered using the mnemonic ‘SHOCK’ (for Septic, Hypovolemic, Obstructive, Cardiogenic, and (K) combinations/other kinds of shock). RESP-F (for exacerbation of chronic Respiratory disease, pulmonary Embolism, ST changes associated with cardiac or pericardial disease, Pneumonia, and heart Failure) can be used for acute respiratory failure. The goals of goal-directed echocardiography in the unstable patient are: assessing global ventricular systolic function, identifying marked right ventricular and left ventricular enlargement, assessing intravascular volume, and the presence of a pericardial effusion. In an urgent or emergent setting, it is recommended to go directly to the best view, which is frequently the subcostal or apical view. The five views are the subcostal four-chamber view, subcostal inferior vena cava view, parasternal long axis view, parasternal short axis view, and the apical four chamber view. Always interpret goal-directed echocardiographic findings in the context of clinically available hemodynamic information. When goal-directed echocardiography is insufficient or when additional abnormalities are appreciated, order a comprehensive echocardiogram. Goal-directed echocardiography and comprehensive echocardiography are not to be used in conflict with each other.

Morbid obesity and optimization of preoperative fluid therapy

BACKGROUND

Preoperative venous return (VR) optimization and adequate blood volume is essential in management of morbidly obese patients (MO) in order to avoid perioperative circulatory instability. In this study, all subjects underwent a preoperative 3-week preparation by rapid-weight-loss-diet (RWL) as part of their treatment program for bariatric surgery.

METHODS

This is a prospective, observational study of 34 morbidly obese patients consecutively scheduled for bariatric surgery at Sunderby County Hospital, Luleå, Sweden. Preoperative transthoracic echocardiography (TTE) was performed in the awake state before and after intravascular volume challenge (VC) of 6 ml colloids/kg ideal body weight (IBW). Effects of standardized VC were evaluated by TTE. Dynamic and non-dynamic echocardiographic indices for VC were studied. Volume responsiveness and level of VR before and after VC were assessed by TTE. An increase of stroke volume ≥13% was considered as a volume responder.

RESULTS

Twenty-nine out of 34 patients were volume responders. After VC, a majority of patients (23/34) were euvolemic, and only 2/34 were hypovolemic. Post-VC hypervolemia was observed in 9/34 of patients.

CONCLUSIONS

The IBW-based volume challenge regime was found to be suitable for preoperative rehydration of RWL-prepared MO. Most of the patients were volume responders. Preoperative state of VR was not associated with volume responsiveness. IBW estimates and appropriate monitoring avoids potential hyperhydration in MO. For VC assessment, conventional Doppler indices were found to be more suitable compared to tissue Doppler, giving sufficient information on pressure-volume correlation of the left ventricle in morbidly obese.

Efficacy of transthoracic echocardiography for diagnosing heart failure in septic shock

BACKGROUND

Cardiac dysfunction occurs in up to 80% of patients with septic shock. Transthoracic echocardiography (TTE) is an ideal tool for the detailed characterization of cardiac function. Its feasibility is perceived to be poor in critically ill patients, but this has never been studied. To address this question, the authors evaluated the efficacy of TTE to diagnose heart failure in septic shock.

METHODS

This was a retrospective study. Patients admitted to the intensive care unit with septic shock and who had a TTE within 72 hours of intensive care unit admission were identified by a computer algorithm and validated by chart review. Echocardiography images were reviewed by a single cardiologist blinded to clinical outcomes. Clinical information was collected from patients' medical record.

RESULTS

Seventy-six patients met the studies' inclusion criteria. The feasibility of TTE to calculate left ventricular ejection fraction was 90% and to assess diastolic function was 74%. Significant mitral regurgitation or aortic stenosis was the most frequent impediments for the assessment of diastolic function. Seventy-four percent of all patients showed some type of cardiac dysfunction (left or right ventricular systolic dysfunction and/or left ventricular diastolic dysfunction). In regression analyses, TTE feasibility was not impacted by factors previously associated with poor image acquisition: high body mass index, mechanical ventilation, tachycardia, advanced age or high severity of illness.

CONCLUSIONS

This study demonstrated that TTE is a useful tool to assess myocardial function in critically ill patients and suggested its potential to assist in the management of patients with septic shock.