Lung Ultrasonography as an Accurate Diagnostic Method for the Diagnosis of Community-Acquired Pneumonia in the Elderly Population

Lung ultrasound in pneumonia: a guide for effective implementation

In patients with pneumonia, lung ultrasound is a useful diagnostic and monitoring tool and has been proven to be superior to physical examination and chest X-ray in terms of feasibility and diagnostic accuracy. Guidelines do not address lung ultrasound as part of the diagnostic workup or as monitoring tool which is surprising. This article provides a succinct overview on the currently available evidence on efficacy and utility of lung ultrasound in patients with a clinical suspicion of pneumonia. Various clinical settings are considered, in addition to limitations, pitfalls and advanced techniques. The aim of this paper is to equip the clinician with the necessary knowledge to maximize lung ultrasound in pneumonia as effective diagnostic and monitoring tool.

Association Between Lung Ultrasound Patterns and Pneumonia

ABSTRACT

Pneumonia is a common respiratory infection that affects the lungs. Lung ultrasound (LUS) is a portable, cost-effective imaging method, which is free of ionizing radiation and has been shown to be useful for evaluating pneumonia. The aim of this retrospective analytical study was to determine the association between lung ultrasound patterns and pneumonia. For the purpose of performing the required analysis, LUS patterns including consolidations, pleural line irregularities, A lines and B lines from 90 subjects (44 patients with confirmed pneumonia and 46 controls) were retrieved from a published open-access data set, which was reviewed and approved by medical experts. A χ 2 test was used for the comparison of categorical variables to determine the association between each LUS pattern and the presence of pneumonia. There is a significant association between LUS consolidation and the presence of pneumonia ( P < 0.0001). Lung ultrasound A lines are significantly associated with the absence of pneumonia ( P < 0.0001), whereas there are no associations between B lines or pleural line irregularities with pneumonia. Lung ultrasound consolidation is found to be associated with the presence of pneumonia. A lines are associated with healthy lungs, and there is no association of B lines and pleural irregularities with the presence of pneumonia. Further studies investigating LUS patterns with clinical information and symptoms of patients with pneumonia are required.

Point-of-Care Ultrasonography in Patients With Acute Dyspnea: An Evidence Report for a Clinical Practice Guideline by the American College of Physicians

BACKGROUND

Dyspnea is a common and often debilitating symptom with a complex diagnostic work-up.

PURPOSE

To evaluate the benefits, harms, and diagnostic test accuracy of point-of-care ultrasonography (POCUS) in patients with acute dyspnea. (PROSPERO: CRD42019126419).

DATA SOURCES

Searches of multiple electronic databases without language limitations (January 2004 to August 2020) and reference lists of pertinent articles and reviews.

STUDY SELECTION

Five randomized controlled trials (RCTs) and 44 prospective cohort-type studies in patients with acute dyspnea evaluated POCUS as a diagnostic tool to determine the underlying cause of dyspnea. Two investigators independently screened the literature for inclusion.

DATA EXTRACTION

Data abstraction by a single investigator was confirmed by a second investigator; 2 investigators independently rated risk of bias and determined certainty of evidence.

DATA SYNTHESIS

Point-of-care ultrasonography, when added to a standard diagnostic pathway, led to statistically significantly more correct diagnoses in patients with dyspnea than the standard diagnostic pathway alone. In-hospital mortality and length of hospital stay did not differ significantly between patients who did or did not receive POCUS in addition to standard diagnostic tests. Finally, POCUS consistently improved the sensitivities of standard diagnostic pathways to detect congestive heart failure, pneumonia, pulmonary embolism, pleural effusion, or pneumothorax; specificities increased in most but not all studies.

LIMITATIONS

Most studies assessed diagnostic test accuracy, which has limited utility for clinical decision making. Studies rarely reported on the proportion of indeterminate sonography results, and no evidence is available on adverse health outcomes of false-positive or false-negative POCUS results.

CONCLUSION

Point-of-care ultrasonography can improve the correctness of diagnosis in patients with acute dyspnea.

PRIMARY FUNDING SOURCE

American College of Physicians.

Diagnostic Performance of Ultrasonography in Patients With Pneumonia: An Updated Comparative Systematic Review and Meta-analysis

Objectives:

A chest radiograph (CXR) is still the preferred diagnostic method when pneumonia is suspected, although the sensitivity is relatively low. The aim of this study was to compare the diagnostic sensitivity, specificity, and accuracy of ultrasonography (US) for the diagnosis of community-acquired pneumonia (CAP), compared with CXR.

Materials and Methods:

A principled search was conducted to identify original English articles using PubMed, EMBASE, Web of Science, Scopus, and the Cochrane library, with the end date of October 2020. A combination of keywords, such as “ultrasound” or “ultrasonography,” “pneumonia,” “sensitivity,” and “specificity,” was used. Methodologic quality was assessed using Quality Assessment of Diagnostic Accuracy Studies 2 criteria. Statistical analysis was completed on the resulting study data.

Results:

The search produced 16 eligible articles that reported on 2040 patients. The overall pooled sensitivity for US and CXR, to diagnose pneumonia, was 0.96 and 0.65, respectively. The overall pooled specificity for US and CXR was 0.85 and 0.81, respectively. The overall pooled positive likelihood ratio for US and CXR was 9.74 and 3.67, respectively. The negative likelihood ratio for US and CXR was 0.05 and 0.42, respectively. In addition, summary receiver operative characteristics areas under the curve were 0.98 for US and 0.77 for CXR.

Conclusion:

This review demonstrated that lung US is a useful technique for the diagnosis of pneumonia. This diagnostic method can be used by emergency physicians with high accuracy, sensitivity, and specificity. Among an elderly population, this diagnostic method may be a better choice than CXR. The rapid performance of lung US may facilitate a quick, cost-effective, and safe diagnosis of this potentially fatal disease.