Effects of respiratory mechanical unloading on thoracoabdominal motion in meconium-injured piglets and rabbits

Andreas Schulze, Cleide Suguihara, Tilo Gerhardt, Peter Schaller, Nelson R Claure, Ruth Everett-Thomas, Eduardo Bancalari

Research output: Contribution to journalArticle

19 Citations (Scopus)

Abstract

Impaired pulmonary mechanics can cause chest wall distortion (CWD) so that work of breathing is dissipated in deforming the rib cage. We hypothesized that respiratory mechanical unloading as a technique of assisted mechanical ventilation would reduce CWD in animals with injured lungs. We studied five piglets and five adult rabbits to test across different ages and chest configurations. As a result of intratracheal meconium instillation, lung compliance decreased from 21 (median; range 17-35) to 9.5 (6.7-14) mL/kPa/kg in rabbits and from 26 (1831) to 7.9 (4.9-11) in piglets. Airway resistance increased from 5.0 (4.6-6.1) to 6.9 (5.8-7.9) kPa/L/s in rabbits only. Respiratory inductive plethysmography was used to measure the phase shift between the rib cage and abdominal compartment movements and the total compartmental displacement ratio. We aimed at unloading at least three- fourths of lung elastance in all animals and 2.0 kPa/L/s of resistance in rabbits. Elastic unloading decreased the phase shift in all but one animal. It reduced the total compartmental displacement ratio from 1.27 (1.14 -3.73) to 1.16 (1.02-1.82) in piglets and from 1.77 (1.45-5.24) to 1.37 (1.114.78) in rabbits. The inspiratory rib cage expansion increased, whereas abdominal expansion did not. The tidal esophageal pressure deflection decreased. Tidal volume increased, whereas respiratory rate remained unaffected so that the partial pressure of arterial CO2 decreased. Resistive unloading as an adjunct to elastic unloading further reduced CWD and induced a more rapid, shallower breathing. We conclude that respiratory unloading as a mechanical support to spontaneous breathing reduces CWD. We speculate that the decrease in CWD increases ventilatory efficiency for a given diaphragmatic effort.

Original languageEnglish
Pages (from-to)191-197
Number of pages7
JournalPediatric Research
Volume43
Issue number2
StatePublished - Jan 1 1998

Fingerprint

Meconium
Thoracic Wall
Rabbits
Lung
Respiration
Work of Breathing
Lung Compliance
Airway Resistance
Plethysmography
Partial Pressure
Tidal Volume
Respiratory Rate
Mechanics
Artificial Respiration
Thorax
Pressure
Rib Cage

ASJC Scopus subject areas

  • Pediatrics, Perinatology, and Child Health

Cite this

Effects of respiratory mechanical unloading on thoracoabdominal motion in meconium-injured piglets and rabbits. / Schulze, Andreas; Suguihara, Cleide; Gerhardt, Tilo; Schaller, Peter; Claure, Nelson R; Everett-Thomas, Ruth; Bancalari, Eduardo.

In: Pediatric Research, Vol. 43, No. 2, 01.01.1998, p. 191-197.

Research output: Contribution to journalArticle

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