Related Experiment Videos
Partitioning of respiratory system resistance in children with respiratory insufficiency
A G Kaditis1, S T Venkataraman, W A Zin
1Department of Pediatrics (Division of Pediatric Pulmonology) , University of Pittsburgh School of Medicine and Children's Hospital of Pittsburgh, Pennsylvania 15213, USA.
Insights
This study found that the DeltaR component of respiratory system resistance is elevated in most children on mechanical ventilation, regardless of lung disease. DeltaR
Area of Science:
- Pediatric Pulmonology
- Respiratory Physiology
- Mechanical Ventilation
Background:
- Respiratory system resistance (Rrs) can be partitioned into flow-resistive (Rint) and viscoelastic/inhomogeneity (DeltaR) components using end-inspiratory airway occlusion.
- Understanding the flow and volume dependence of these components is crucial for optimizing mechanical ventilation in children.
Purpose of the Study:
- To investigate the flow and volume dependence of Rrs, Rint, and DeltaR in pediatric patients undergoing mechanical ventilation.
- To compare these parameters in children with and without primary lung disorders.
Main Methods:
- End-inspiratory airway occlusion was used to measure Rrs, Rint, and DeltaR in 13 children on mechanical ventilation.
- Subjects were divided into two groups: Group 1 (pulmonary insufficiency) and Group 2 (no primary lung disorder).
- Flow and volume dependence of Rrs, Rint, and DeltaR were analyzed under isovolume and isoflow conditions.
Main Results:
- DeltaR was elevated in most mechanically ventilated children, irrespective of primary lung disease.
- Rint was increased in lower airway obstruction and in most patients without primary lung disorder, but less so in parenchymal lung disease.
- DeltaR decreased with increasing flow and increased with increasing tidal volume, exhibiting opposite dependence compared to airway resistance.
Conclusions:
- The DeltaR component is significantly affected in pediatric patients on mechanical ventilation, indicating viscoelasticity and inhomogeneity.
- The distinct flow and volume dependencies of DeltaR suggest it reflects different pathophysiological mechanisms than Rint.
- These findings highlight the importance of assessing DeltaR for a comprehensive understanding of respiratory mechanics in ventilated children.
Abstract:
Using end-inspiratory airway occlusion, respiratory system resistance (Rrs) can be partitioned into a flow-resistive component (Rint), and an additional component (DeltaR), reflecting viscoelasticity and time constant inequalities. We studied flow and volume dependence of Rrs and its subdivisions (Rint and DeltaR) in 13 children, seven mechanically ventilated for pulmonary insufficiency (Group 1; six with parenchymal lung disease; one with lower airway obstruction) and six without primary lung disorder (Group 2). In comparison with healthy children, Rint was increased in the patient with lower airway obstruction and five of six patients without primary lung disorder but in only one of six with parenchymal lung disease. DeltaR was increased in all seven patients in Group 1 and in four of six patients in Group 2. The directions of changes in Rint and Rrs with increasing flow (isovolume conditions) and with increasing volume (isoflow conditions) were variable. DeltaR decreased exponentially (p < 0.05) with increasing flow in 11 of 13 subjects and increased with increasing tidal volume (VT) in 12 of 13. Thus, DeltaR was increased in most children on mechanical ventilation with or without primary lung disease; its volume and flow dependence were opposite to that of airway resistance.