Variability of dynamic compliance measurements in spontaneously breathing and ventilated newborn infants

Abstract

We studied reproducibility and variability of dynamic pulmonary compliance (Cdyn) by making measurements with the esophageal balloon at multiple locations within the esophagus, in both spontaneously breathing and mechanically ventilated newborn infants. Reliable measurements could be obtained over a range similar to that reported for measurements with a liquid-filled catheter. In spontaneously breathing infants Cdyn was found to be highly variable. This variability was unrelated to catheter position but was associated with concomitant changes in pulmonary resistance. Probably because of the high variability, the correlation of Cdyn with a measurement of respiratory system compliance (Crs) was rather poor (r = 0.63). Cdyn measured in mechanically ventilated infants was significantly less variable and compared favorably to Crs (r = 0.86), but its accuracy could not be adequately assessed since the comparison of esophageal and airway occlusion pressure was not feasible in all infants. In addition, significant differences in Cdyn were found between spontaneous and ventilated breaths during mechanical ventilation. Further studies in both ventilated and spontaneously breathing infants are needed to assess the variability of Cdyn over extended time periods.

Influence of Chest Wall Distortion and Esophageal Catheter Position on Esophageal Manometry in Preterm Infants

“…Nor is this interpretation supported by two recent studies (9,16). Ratjen and Wiesemann (16) found the variability of compliance measurements in preterm infants independent from catheter position.…”

“…Nor is this interpretation supported by two recent studies (9,16). Ratjen and Wiesemann (16) found the variability of compliance measurements in preterm infants independent from catheter position. Coates et al (9) documented that, in preterm infants with chest wall distortion, esophageal and airway pressure changes were equal when the catheter tip was between cardia and level of the carina.…”

“…Because all differences were small and well within the inter-and intrapatient variability for neonates, they are probably not of clinical importance (15,16).…”

Frequency responses of infant air-balloon versus liquid-filled catheters for intra-esophageal pressure measurement

“…8 WFC absolute pressure measurements are altered when the vertical distance between catheter-tip and transducer is changed, and WFCs are also sensitive to motion artifacts. 9 The long IABC balloon measures mean intraesophageal pressure over a larger portion of the lower esophagus than do WFCs or single micro-tip transducer catheters, making it more likely that the mean value of an unevenly distributed intra-thoracic pleural pressure [18][19][20] is recorded. IABCs are subject neither to measurement errors related to the dissipation of liquid volume around WFC tips 21 nor to worsened dynamic performance from the introduction of gas microbubbles into WFCs.…”

Correctly selecting a liquid-filled nasogastric infant feeding catheter to measure intraesophageal pressure

“…[1][2][3] Commercial nasogastric liquid-filled feeding catheters are easily inserted and well tolerated 4,5 and are readily available to clinicians as disposable and inexpensive alternatives to balloon 2,6,7 or transducer-tip 8 catheters. In addition, liquidfilled feeding catheters are advantageous for intraesophageal pressure measurements in mechanically ventilated infants because the catheters are normally in situ for long-term nasogastric feeding.…”