Lung Ultrasound and Blood Gas-Based Classification of Critically Ill Patients with Dyspnea: A Pathophysiologic Approach

Neonatal and paediatric point-of-care ultrasound review

Purpose

Point-of-care ultrasound (POCUS) examinations for children and newborns are different from POCUS exams for adults due to dissimilarities in size and body composition, as well as distinct surgical procedures and pathologies in the paediatric patient. This review describes the major paediatric POCUS exams and how to perform them and summarizes the current evidence-based perioperative applications of POCUS in paediatric and neonatal patients.

Method

Literature searches using PubMed and Google Scholar databases for the period from January 2000 to November 2021 that included MeSH headings of [ultrasonography] and [point of care systems] and keywords including "ultrasound" for studies involving children aged 0 to 18 years.

Results

Paediatric and neonatal POCUS exams can evaluate airway, gastric, pulmonary, cardiac, abdominal, vascular, and cerebral systems.

Discussion

POCUS is rapidly expanding in its utility and presence in the perioperative care of paediatric and neonatal patients as their anatomy and pathophysiology are uniquely suited for ultrasound imaging applications that extend beyond the standard adult POCUS exams.

Conclusions

Paediatric POCUS is a powerful adjunct that complements and augments clinical diagnostic evaluation and treatment.

Accuracy of Critical Care Ultrasonography Plus Arterial Blood Gas Analysis Based Algorithm in Diagnosing Aetiology of Acute Respiratory Failure

Introduction

Lung ultrasound when used in isolation, usually misses out metabolic causes of dyspnoea and differentiating acute exacerbation of COPD from pneumonia and pulmonary embolism is difficult, hence we thought of combining critical care ultrasonography (CCUS) with arterial blood gas analysis (ABG).

Aim of the study

The objective of this study was to estimate accuracy of Critical Care Ultrasonography (CCUS) plus Arterial blood gas (ABG) based algorithm in diagnosing aetiology of dyspnoea. Accuracy of traditional Chest X-ray (CxR) based algorithm was also validated in the following setting.

Methods

It was a facility based comparative study, where 174 dyspneic patients were subjected to CCUS plus ABG and CxR based algorithms on admission to ICU. The patients were classified into one of five pathophysiological diagnosis 1) Alveolar( Lung-pneumonia)disorder ; 2) Alveolar (Cardiac-pulmonary edema) disorder; 3) Ventilation with Alveolar defect (COPD) disorder ;4) Perfusion disorder; and 5) Metabolic disorder. We calculated diagnostic test properties of CCUS plus ABG and CXR based algorithm in relation to composite diagnosis and correlated these algorithms for each of the defined pathophysiological diagnosis.

Results

The sensitivity of CCUS and ABG based algorithm was 0.85 (95% CI-75.03-92.03) for alveolar (lung) ; 0.94 (95% CI-85.15-98.13) for alveolar (cardiac); 0.83 (95% CI-60.78-94.16) for ventilation with alveolar defect; 0.66 (95% CI-30-90.32) for perfusion defect; 0.63 (95% CI-45.25-77.07) for metabolic disorders.Cohn's kappa correlation coefficient of CCUS plus ABG based algorithm in relation to composite diagnosis was 0.7 for alveolar (lung), 0.85 for alveolar (cardiac), 0.78 for ventilation with alveolar defect, 0.79 for perfusion defect and 0.69 for metabolic disorders.

Conclusion

CCUS plus ABG algorithm is highly sensitive and it's agreement with composite diagnosis is far superior. It is a first of it's kind study, where authors have attempted combining two point of care tests and creating an algorithmic approach for timely diagnosis and intervention.

Should the ultrasound probe replace your stethoscope? A SICS-I sub-study comparing lung ultrasound and pulmonary auscultation in the critically ill

Background

In critically ill patients, auscultation might be challenging as dorsal lung fields are difficult to reach in supine-positioned patients, and the environment is often noisy. In recent years, clinicians have started to consider lung ultrasound as a useful diagnostic tool for a variety of pulmonary pathologies, including pulmonary edema. The aim of this study was to compare lung ultrasound and pulmonary auscultation for detecting pulmonary edema in critically ill patients.

Methods

This study was a planned sub-study of the Simple Intensive Care Studies-I, a single-center, prospective observational study. All acutely admitted patients who were 18 years and older with an expected ICU stay of at least 24 h were eligible for inclusion. All patients underwent clinical examination combined with lung ultrasound, conducted by researchers not involved in patient care. Clinical examination included auscultation of the bilateral regions for crepitations and rhonchi. Lung ultrasound was conducted according to the Bedside Lung Ultrasound in Emergency protocol. Pulmonary edema was defined as three or more B lines in at least two (bilateral) scan sites. An agreement was described by using the Cohen κ coefficient, sensitivity, specificity, negative predictive value, positive predictive value, and overall accuracy. Subgroup analysis were performed in patients who were not mechanically ventilated.

Results

The Simple Intensive Care Studies-I cohort included 1075 patients, of whom 926 (86%) were eligible for inclusion in this analysis. Three hundred seven of the 926 patients (33%) fulfilled the criteria for pulmonary edema on lung ultrasound. In 156 (51%) of these patients, auscultation was normal. A total of 302 patients (32%) had audible crepitations or rhonchi upon auscultation. From 130 patients with crepitations, 86 patients (66%) had pulmonary edema on lung ultrasound, and from 209 patients with rhonchi, 96 patients (46%) had pulmonary edema on lung ultrasound. The agreement between auscultation findings and lung ultrasound diagnosis was poor (κ statistic 0.25). Subgroup analysis showed that the diagnostic accuracy of auscultation was better in non-ventilated than in ventilated patients.

Conclusion

The agreement between lung ultrasound and auscultation is poor.

Trial registration

NCT02912624. Registered on September 23, 2016.

The role of point-of-care ultrasound in pediatric acute respiratory distress syndrome: emerging evidence for its use

Pediatric acute respiratory distress syndrome (PARDS) remains an important cause of significant morbidity and mortality. The 2015 PALICC definition of PARDS requires chest imaging to diagnose the presence of new pulmonary infiltrate(s). Traditionally chest radiography or computerised tomography have been used. However, these carry the limitations of exposure to ionizing radiation, need to transfer the critically unwell child, lag-time with clinical correlation and lack of immediate results. The use of point of care ultrasound (POCUS) has been well established in adult emergency medicine and critical care. Furthermore, the adult literature clearly demonstrates that lung POCUS is a safe and validated tool, which is highly sensitive and specific when compared to chest radiography for differentiating the causes of respiratory failure, including ARDS. Whilst pediatric specific data is limited, it has been shown that the signs seen in adults are reproducible in critically ill neonates and children. Furthermore, the numerous benefits of POCUS in the paediatric setting are compelling and include lack of ionizing radiation, immediate feedback, promoting time at the bedside of the critically unwell child, and ease of serial assessments. This review article presents the emerging evidence demonstrating that lung POCUS can be used not only to support the diagnosis of pediatric ARDS, but also to assess for complications, monitor progression and thus guide management. We hope it will stimulate much needed collaborative research into this exciting field of imaging and its applications to PARDS and beyond.