Measurement of Ventilation and Respiratory Mechanics during Continuous Positive Airway Pressure (CPAP) Treatment in Infants

Abstract

A new method has been evaluated for measuring ventilation and lung mechanics in spontaneously breathing infants by means of a face chamber. Airway flow is measured with a pneumotachograph inserted between the face chamber and a stable pressure source. Oesophageal pressure is measured via a water-filled oesophageal catheter. The method is suitable for use in conjunction with continuous positive airway pressure (CPAP) treatment in neonatal intensive care. A flat frequency response curve up to 15 Hz for the two measuring systems (i.e., airway flow and oesophageal pressure), and a time shift between the two respective signals of less than 2 msec are prerequisites for correct evaluation of respiratory mechanics. In preterm infants with chest distortion, the inhomogeneity of pleural pressure affects the significance of resistance and compliance values, as calculated from oesophageal pressure. Supra-diaphragmatic pressure variations reflect the resistive and elastic load on the diaphragm exerted by the lungs and thorax. Thus, oesophageal pressure is still useful in studies of respiratory mechanics in preterm infants.

Pioneers in Mechanical Ventilation: Björn Jonson

“…17 Based on the combination of the face chamber and the ventilator, we became, under Nils Svenningsen, a global leader in neonatal ventilation. [17][18][19][20][21][22] My group has studied basic physiology related to pulmonary surfactant. When a wetting agent is administered to the alveoli, the permeability of the alveolocapillary membrane increases more than 100 times.…”

Einfluß eines Hintergrundflows auf die Genauigkeit der Atemflow- und Atemvolumenmessung bei Neugeborenen - Effect of a Background Flow on the Accuracy of Ventilatory Measurements in Neonates

“…Messung von -Ventilation und Atemmechanik [2,16,19], -pulmonalem Gasvolumen durch das N 2 -Auswaschverfahren [6,20], -Sauerstoff verbrauch und CO 2 -Produktion [3,4,17] und -regionalen Verteilungsstörungen mittels Lungenszintigraphie [11]. t .…”

“…Gegenüber der direkten Frequenzgangmessung mit periodischen (meist sinusförmigen) Meßsignalen [2,18] sind bei sprungförmigen Testsignalen der apparative Aufwand für die Signalerzeugung und die Meßdauer erheblich geringer. Außerdem bereitet die Signaleinspeisung in die gesamte Meßanordnung kaum Probleme.…”

“…°C). Die Gesichtsmaske wurde ebenso wie die schon in bisherigen Meßplätzen[2,13,19] eingesetzte Gesichtskammer für die Einspeisung des Hintergrundflows durch Anbringen zusätzlicher Schlauchanschlüsse modifiziert; er betrug bei den statischen und dynamischen Messungen 0, 3, 5 und 7 l/min (Bilder 2a und 2b). Beide wurden im Modellversuch mit einer ebenen Unterlage abgedichtet.…”

Airway and body surface sensors for triggering in neonatal ventilation

“…The catheter had a closed tip and two side holes in its distal 1.5cm. The catheter tip was withdrawn from the stomach and adjusted until maximum negative inspiratory deflections were observed during airway occlusion (12).…”