Ultrasound may help diagnose pediatric pneumonia

By Lisa Rapaport

NEW YORK (Reuters Health) - A portable ultrasound may be effective at diagnosing pediatric pneumonia, a small study suggests, potentially offering a more affordable and accessible alternative to chest X-rays.

"Pneumonia is one of the top killers of children in the world and there are many challenges in the diagnosis and management, particularly in regions where X-rays are unavailable," senior author Dr. William Checkley, medical director of Johns Hopkins University International, told Reuters Health in a phone interview. "We wanted to see if a portable, battery-operated ultrasound could be an alternative for imaging in pneumonia and our findings suggest that it is."

Dr. Checkley and colleagues did a systematic literature review, screening 1,475 research articles and then using eight of the published papers to perform a meta-analysis to assess the effectiveness of lung ultrasounds for diagnosing pediatric pneumonia.

Overall, the 8 studies involved 765 children, with a mean age of 5 years (range, 0 to 17). Five were performed in Italy, one in China, one in Egypt, and one in the United States, according to an article published online March 16 in Pediatrics.

One study in the review was conducted at multiple centers and the rest were single-center studies. Seven of the studies were blinded to outcomes of chest radiographs before lung ultrasound performance.

Three of the studies followed the disease course until the consolidation was resolved. Two studies enrolled patients with suspected neonatal pneumonia and severe disease, and six studies enrolled children with suspected community-acquired pneumonia.

The overall pooled sensitivity and specificity for the diagnosis of pneumonia using lung ultrasound came to 96% and 93%, respectively. Positive and negative likelihood ratios were 15.3 and 0.06, respectively.

In subgroup analysis, with the reference standard limited to findings based on chest radiographs alone, the researchers found that the sensitivity of lung ultrasound was similar to that when both clinical criteria and chest radiographs were used to define childhood pneumonia. But specificity decreased to 84%, likely reflecting that chest radiograph alone is inadequate for the diagnosis of pneumonia.

The meta-analysis had some limitations. Most studies included were heterogeneous, and didn't have large numbers of children. Also, not every study compared lung ultrasound results with a clinical diagnosis, and in some studies the final diagnosis was based only on chest radiographs without the influence of clinical data.

These preliminary data "show we can be highly successful using lung ultrasound as a potential tool for pneumonia diagnosis," said Checkley. "More research is needed, but this has the potential to change clinical practice, especially in settings where resources for X-rays aren't available, but also in the U.S., where you may want an alternative that doesn't expose children to radiation."

The current gold standard for diagnosing pediatric pneumonia, a clinical assessment combined with a computed tomography (CT), isn't always available, agreed Dr. Brian Coley, chief radiologist at Cincinnati Children's Hospital Medical Center. But it's too soon to say whether ultrasound should be widely used to diagnose pneumonia when X-rays are available, he said.

Coley, who is also president of the Society of Pediatric Radiology and president-elect of the American Institute for Ultrasound in Medicine, also noted that the studies in the meta-analysis were based on examinations done at acute care centers where clinicians may be more experienced. It's unclear whether the findings would be similar for screenings done in community clinics with less-experienced practitioners, he said.

Still, the meta-analysis rightly concludes that lung ultrasound may be a promising tool to help diagnose pediatric pneumonia, Coley, who wasn't involved in the study, told Reuters Health by email.

In resource-limited settings, the ultrasound requires less infrastructure than any other imaging modality, Coley said. "If you have a solar panel or a bicycle-powered generator, you can recharge a portable ultrasound machine's battery. You don't need commercial ultrasound gel to scan; you can use cooking oil as an acoustic coupling medium on the skin."

"If my clinic in Uganda has one bucket of antibiotics provided by an (nongovernmental organization) to last the next month, I want to use them only when appropriate, not like the U.S. where everyone with an upper respiratory virus or sinus drainage can get a Zpac," Coley said. "If ultrasound helps me to decide who likely does or does not have pneumonia, I can dole out my medications more appropriately and take care of more people who need them, which might even be better antimicrobial stewardship than is often practiced in developed settings."

The National Institutes of Health partially supported this research. The authors declared no conflicts of interest.

SOURCE: http://bit.ly/1DxOx0r

Pediatrics 2015.

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