Clinician-performed ultrasound in hemodynamic and cardiac assessment: a synopsis of current indications and limitations

Current status of point of care ultrasonography for the perioperative care of trauma patients

PURPOSE OF REVIEW

The incorporation of point of care ultrasound into the field of anesthesiology and perioperative medicine is growing at rapid pace. The benefits of this modality align with the acuity of patient care and decision-making in anesthetic care of a trauma patient.

RECENT FINDINGS

Cardiac ultrasound can be used to diagnose cardiac tamponade or investigate the inferior vena cava to assess volume status in patients who may suffer from hemorrhagic shock. Thoracic ultrasound may be used to rapidly identify pneumothorax or hemothorax in a patient suffering chest wall trauma. In addition, investigators are exploring the utility of ultrasonography in traumatic airway management and elevated intracranial pressure. In addition, the utility of gastric ultrasound on trauma patients is briefly discussed.

SUMMARY

Incorporation of point of care ultrasound techniques into the practice of trauma anesthesiology is important for noninvasive, mobile and expeditious assessment of trauma patients. In addition, further large-scale studies are needed to investigate how point of care ultrasound impacts outcomes in trauma patients.

Monitoring patients with acute dyspnea with serial point-of-care ultrasound of the inferior vena cava (IVC) and the lungs (LUS): a systematic review

PURPOSE

The primary aim was to investigate if treatment guided by serial ultrasound of the inferior vena cava-collapsibility index (IVC-CI) and B-lines on lung ultrasound (LUS) could reduce mortality, readmissions, and length of stay (LOS) in acutely dyspneic patients admitted to a hospital, compared to standard monitoring. The secondary aim was to determine how the changes of B-lines and IVC-CI are correlated to vitals and symptoms.

METHODS

A systematic search was conducted on PubMed, Embase, Cochrane, Google Scholar, Web of Science, Scopus, OpenGrey, ProQuest, and databases for ongoing trials. The risk of bias was assessed according to study design.

RESULTS

Of the 8258 studies identified, 50 were selected for full-text screening, and 24 studies were chosen for data extraction (19 pre-post-, two non-randomized controlled-, two randomized controlled-, and one retrospective cohort study), covering 2040 patients. Most studies were single-center and had small study populations with only heart failure patients. The risk of bias was high. No studies evaluated how the difference between two ultrasound measurements correlated with the primary outcomes. Seven studies reported that a decline in either B-lines or IVC size, or an increased IVC-CI reduced mortality, readmissions, and LOS when correlated to a single ultrasound measurement. All studies showed changes in the IVC-CI and B-lines, but these were not related to vitals or symptoms.

CONCLUSION

B-lines and IVC-CI are dynamic variables that change over time and with treatment. A single ultrasound measurement can influence prognostic outcomes, but it remains uncertain if repeated scans can have the same impact.

Automated Volume Status Assessment Using Inferior Vena Cava Pulsatility

Assessment of volume status is important to correctly plan the treatment of patients admitted and managed by cardiology, emergency and internal medicine departments. Non-invasive assessment of volume status by echography of the inferior vena cava (IVC) is a promising possibility, but its clinical use is limited by poor reproducibility of current standard procedures. We have developed new algorithms to extract reliable information from non-invasive IVC monitoring by ultrasound (US) imaging. Both long and short axis US B-mode video-clips were taken from 50 patients, in either hypo-, eu-, or hyper-volemic conditions. The video-clips were processed to extract static and dynamic indexes characterizing the IVC behaviour. Different binary tree models (BTM) were developed to identify patient conditions on the basis of those indexes. The best classifier was a BTM using IVC pulsatility indexes as input features. Its accuracy (78.0% when tested with a leave-one-out approach) is superior to that achieved using indexes measured by the standard clinical method from M-mode US recordings. These results were obtained with patients in conditions of normal respiratory function and cardiac rhythm. Further studies are necessary to extend this approach to patients with more complex cardio-respiratory conditions.

Optimisation of Heart Failure Management in Nursing Homes Using Point-of-Care Ultrasonography: Harmonious Trial Rationale and Design

Introduction

Heart failure is common in the nursing home population and presents many diagnostic and therapeutic challenges. Point-of-care ultrasonography is a bedside method that can be used to assess volume status more reliably than clinical examination. This trial was conceived to test whether point-of-care ultrasonography-guided management improves heart failure outcomes among nursing home residents.

Methods

Nursing home residents with heart failure will be enrolled in a multi-centre, prospective, randomised controlled trial. Residents will first be screened for heart failure. Patients with heart failure will be randomised in 1:1 fashion into two groups. Nursing home physicians will adjust diuretic therapy according to volume status for six months. Point-of-care ultrasonography will be used in the test group and clinical examination in the control group. The primary endpoint will be heart failure deterioration, defined as a composite of any of the following four events: the need for an intravenous diuretic application, the need for an emergency service intervention, the need for unplanned hospitalisation for non-injury causes, or death from whatever cause.

Expected results

The expected prevalence of heart failure among nursing home residents is above 10%. Point-of-care ultrasonography-guided heart failure management will reduce the number of deteriorations of heart failure in the nursing home population.

Conclusion

This study will explore the usefulness of point-of-care ultrasonography for heart failure management in the nursing home population.

Monitoring patients with acute dyspnoea with a serial focused ultrasound of the heart and the lungs (MODUS): a protocol for a multicentre, randomised, open-label, pragmatic and controlled trial

INTRODUCTION

Among patients admitted to an emergency department, dyspnoea is one of the most common symptoms. Patients with dyspnoea have high mortality and morbidity. Therefore, novel methods to monitor the patients are warranted. The aim is to investigate whether therapy guided by monitoring patients with acute dyspnoea with serial ultrasound examinations of the heart and the lungs together with standard care can change the severity of dyspnoea compared with treatment guided by standard monitoring alone.

METHODS AND ANALYSIS

The study will be conducted as a multicentre, randomised, pragmatic, open-label and controlled trial where patients admitted with acute dyspnoea to an emergency ward will be randomised into a standard care group and a serial ultrasound group with 103 patients in each. All patients will be examined with an ultrasound of the heart and the lungs upfront. In addition, the patients in the serial ultrasound group will be examined with an ultrasound of the heart and lungs two more times to guide further therapy during the admittance. The primary outcome is a change in dyspnoea on a verbal scale. After discharge, the patients are followed for 1 year to assess the number of readmissions, death and length of hospital stay.

ETHICS AND DISSEMINATION

The trial is conducted in accordance with the Declaration of Helsinki and approved by The Regional Committee on Health Research Ethics for Region Zealand, Denmark (identifier SJ-744). Data handling agreement with participating centres has been made (identifier REG-056-2019). The General Data Protection Regulation and the Danish Data Protection Act will be respected. The results of the trial will be reported in peer-reviewed scientific journals regardless of the outcomes.

TRIAL REGISTRATION NUMBER

NCT04091334.

Effectiveness of serial focused ultrasound of the lungs and inferior vena cava for monitoring patients with acute dyspnea: a systematic review protocol

OBJECTIVE

The objective of this review is to evaluate the effectiveness of serial focused ultrasound of the lungs (FLUS) and/or inferior vena cava (IVC) compared to standard care for monitoring patients with acute dyspnea.

INTRODUCTION

Acute dyspnea is one of the most common complaints reported by patients in hospital emergency departments, and has high in-hospital mortality rates. The current methods of monitoring patients with acute dyspnea lack both sensitivity and specificity. Point-of-care FLUS and IVC is a promising monitoring tool, but an overview of the existing evidence is absent.

INCLUSION CRITERIA

This review will include studies of adult patients admitted to hospital with acute dyspnea that is examined via FLUS, IVC or both a minimum of twice during hospitalization compared to standard care.

METHODS

The following electronic databases will be searched: PubMed, Cochrane, Embase, Scopus, Web of Science and Google Scholar. Gray literature will be sought in OpenGrey and ProQuest. The search is limited to articles written in English, Danish, Swedish, Norwegian and German. Articles published before 2003 will be excluded from the search and duplicates will be removed. Two independent reviewers will screen and critically appraise the included studies and perform the data extraction. If possible, data will be synthesized with statistical meta-analysis; otherwise, data will be presented in narrative form.

SYSTEMATIC REVIEW REGISTRATION NUMBER

PROSPERO CRD42018116608.

The utility of point-of-care ultrasound in the assessment of volume status in acute and critically ill patients

BACKGROUND

Volume resuscitation has only been demonstrated to be effective in approximately fifty percent of patients. The remaining patients do not respond to volume resuscitation and may even develop adverse outcomes (such as acute pulmonary edema necessitating endotracheal intubation). We believe that point-of-care ultrasound is an excellent modality by which to adequately predict which patients may benefit from volume resuscitation.

DATA RESOURCES

We performed a search using PubMed, Scopus, and MEDLINE. The following search terms were used: fluid responsiveness, ultrasound, non-invasive, hemodynamic, fluid challenge, and passive leg raise. Preference was given to clinical trials and review articles that were most relevant to the topic of assessing a patient's cardiovascular ability to respond to intravenous fluid administration using ultrasound.

RESULTS

Point-of-care ultrasound can be easily employed to measure the diameter and collapsibility of various large vessels including the inferior vena cava, common carotid artery, subclavian vein, internal jugular vein, and femoral vein. Such parameters are closely related to dynamic measures of fluid responsiveness and can be used by providers to help guide fluid resuscitation in critically ill patients.

CONCLUSION

Ultrasound in combination with passive leg raise is a non-invasive, cost- and time-effective modality that can be employed to assess volume status and response to fluid resuscitation. Traditionally sonographic studies have focused on the evaluation of large veins such as the inferior vena cava, and internal jugular vein. A number of recently published studies also demonstrate the usefulness of evaluating large arteries to predict volume status.

Point-of-care ultrasound in pediatric anesthesiology and critical care medicine

Ultrasound has increasingly become a clinical asset in the hands of the anesthesiologist and intensivist who cares for children. Though many applications for ultrasound parallel adult modalities, children as always are not simply small adults and benefit from the application of ultrasound to their management in various ways. Body composition and size are important factors that affect ultrasound performance in the child, as are the pathologies that may uniquely afflict children and aspects of procedures unique to this patient population. Ultrasound simplifies vascular access and other procedures by visualizing structures smaller than those in adults. Maturation of the thoracic cage presents challenges for the clinician performing pulmonary ultrasound though a greater proportion of the thorax can be seen. Moreover, ultrasound may provide unique solutions to sizing the airway and assessing it for cricothyroidotomy. Though cardiac ultrasound and neurosonology have historically been performed by well-developed diagnostic imaging services, emerging literature stresses the utility of clinician ultrasound in screening for pathology and providing serial observations for monitoring clinical status. Use of ultrasound is growing in clinical areas where time and diagnostic accuracy are crucial. Implementation of ultrasound at the bedside will require institutional support of education and credentialing. It is only natural that the pediatric anesthesiologist and intensivist will lead the incorporation of ultrasound in the future practice of these specialties.

Keys to successful organ procurement: An experience-based review of clinical practices at a high-performing health-care organization

Organ procurement (OP) from donors after brain death and circulatory death represents the primary source of transplanted organs. Despite favorable laws and regulations, OP continues to face challenges for a number of reasons, including institutional, personal, and societal barriers. This focused review presents some of the key components of a successful OP program at a large, high-performing regional health network. This review focuses on effective team approaches, aggressive resuscitative strategies, optimal communication, family support, and community outreach efforts.

Correlations between pulmonary artery pressures and inferior vena cava collapsibility in critically ill surgical patients: An exploratory study

INTRODUCTION

As pulmonary artery catheter (PAC) use declines, search continues for reliable and readily accessible minimally invasive hemodynamic monitoring alternatives. Although the correlation between inferior vena cava collapsibility index (IVC-CI) and central venous pressures (CVP) has been described previously, little information exists regarding the relationship between IVC-CI and pulmonary artery pressures (PAPs). The goal of this study is to bridge this important knowledge gap. We hypothesized that there would be an inverse correlation between IVC-CI and PAPs.

METHODS

A post hoc analysis of prospectively collected hemodynamic data was performed, examining correlations between IVC-CI and PAPs in a convenience sample of adult Surgical Intensive Care Unit patients. Concurrent measurements of IVC-CI and pulmonary arterial systolic (PAS), pulmonary arterial diastolic (PAD), and pulmonary arterial mean (PAM) pressures were performed. IVC-CI was calculated as ([IVCmax - IVCmin]/IVCmax) × 100%. Vena cava measurements were obtained by ultrasound-credentialed providers. For the purpose of correlative analysis, PAP measurements (PAS, PAD, and PAM) were grouped by terciles while the IVC-CI spectrum was divided into thirds (<33, 33-65, ≥66).

RESULTS

Data from 34 patients (12 women, 22 men, with median age of 59.5 years) were analyzed. Median Acute Physiologic Assessment and Chronic Health Evaluation II score was 9. A total of 76 measurement pairs were recorded, with 57% (43/76) obtained in mechanically ventilated patients. Correlations between IVC-CI and PAS (rs = -0.334), PAD (rs = -0.305), and PAM (rs = -0.329) were poor. Correlations were higher between CVP and PAS (R2 = 0.61), PAD (R2 = 0.68), and PAM (R2 = 0.70). High IVC-CI values (≥66%) consistently correlated with measurements in the lowest PAP ranges. Across all PAP groups (PAS, PAD, and PAM), there were no differences between the mean measurement values for the lower and middle IVC-CI ranges (0%-65%). However, all three groups had significantly lower mean measurement values for the ≥66% IVC-CI group.

CONCLUSIONS

Low PAS, PAD, and PAM measurements show a reasonable correlation with high IVC-CI (≥66%). These findings are consistent with previous descriptions of the relationship between IVC-CI and CVP. Additional research in this area is warranted to better describe the hemodynamic relationship between IVC-CI and PAPs, with the goal of further reduction in the reliance on the use of PACs.