Rapid diagnosis of respiratory distress syndrome by oral aspirate in premature newborns

Abstract

The study suggests that the stable microbubble test performed on oral aspirate is a reliable alternative to that performed on gastric fluid for the prediction of respiratory distress syndrome in the newborn.

Biochemical and Lung Function Test Accuracy for Predicting the Need for Surfactant Therapy in Preterm Infants: A Systematic Review

“…The sample processing for SMT was reproducible across the studies. However, we found substantial differences in the analysis for: (1) microbubble (MB) size (from 10 to 25 μm); (2) main parameters considered (absolute number per unit or proportion of MB or average diameter); (3) computerized [21, 22] versus manual counts [18, 19, 23, 24]. The procedures for the LBC analysis also differed.…”

“…One study [24] enrolled patients consecutively until the desired sample of both target and control infants was reached. Half of the studies followed a convenience series based on operator availability [19, 20, 23, 25], and three studies did not provide sufficient details on patient selection [18, 21, 22]. All included studies had a prospective cohort trial design.…”

“…We evaluated the accuracy of biochemical and lung function tests to assess the need for surfactant. Eight studies [18][19][20][21][22][23][24][25] addressed the objective of the systematic review. They included four different tests (CT, SMT, LBC on GASP, and FOT) performed in the early postnatal period (within 3 h from birth) to evaluate the need for surfactant in preterm infants ≤34 weeks gestation who did not require intubation at birth.…”

“…This heterogeneity might be due to differences in (1) the study population (more mature infants, higher use of antenatal steroids, variation in the definition of RDS, diverse level of care) or (2) methods for sampling, processing, and analyzing data. For instance, the studies on SMT considered different MB sizes (from 10 to 25 μm), various parameters for defining the cut-off (absolute number, proportion, or average diameter of MB for a given sampling area) [18,19,[21][22][23][24]; sometimes the analysis was performed by an operator [18,19,23,24], sometimes by a computerized program [21,22]; some studies used fresh [19,24] while others frozen samples [18,[21][22][23]. However, above all, one of the study's significant limitations was the lack of a proper gold standard.…”

“…Whereas there was a general agreement in the definition of RDS, encompassing signs of work of breathing, hypoxia, and typical imaging findings, the definition of the reference standard for surfactant therapy varied, despite oxygen requirement as the basis. The majority of the index tests were biochemical tests on the gastric aspirate (GASP) [18,19,[21][22][23][24][25] in one study only on oral aspirate [23], comprising the click test (CT) [18], the stable microbubble test (SMT) [18,19,[21][22][23][24] and the lamellar body count (LBC) [24,25]. A single study applied lung function testing as an index test: the FOT, evaluating respiratory mechanics, in particular, lung reactance as a marker of lung recruitment [20].…”