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Lung and chest wall mechanics in anesthetized children. Influence of body position
J Ingimarsson1, A Thorsteinsson, A Larsson
1Departments of Anesthesia and Intensive Care, University Hospital, Lund, Sweden.
Insights
Respiratory mechanics in children were studied using pressure-volume curves. Lung and chest wall mechanics varied significantly between supine and lateral positions, correlating with body size.
Area of Science:
- Pediatric Respiratory Physiology
- Thoracic Biomechanics
Background:
- Mechanical behavior of the lung and chest wall is not well-defined in preschool children.
- Understanding respiratory mechanics is crucial for pediatric respiratory care.
Purpose of the Study:
- To determine the static expiratory pressure-volume (P-V) curves of the respiratory system in anesthetized children.
- To partition respiratory system mechanics into lung and chest wall components.
- To investigate the influence of body position (supine vs. lateral) on respiratory mechanics and their relation to growth.
Main Methods:
- Obtained static expiratory P-V curves in 17 anesthetized children (0.2 to 15.5 yr).
- Measured esophageal (Pes) and airway pressure (Paw) to partition lung and chest wall mechanics.
- Calculated inspiratory capacity (IC), chest wall elastance (Ecw), respiratory system compliance (Crs), and lung compliance (C(lung)).
Main Results:
- Lung compliance (C(lung)) increased with growth and was similar in both positions.
- Respiratory system compliance (Crs) and inspiratory capacity (IC) were ~20% greater in the supine position.
- Chest wall elastance (Ecw) was significantly lower in the supine position (12%) compared to the lateral position (33%).
Conclusions:
- Respiratory mechanics in children correlate strongly with body size.
- Significant differences in respiratory mechanics exist between supine and lateral positions, particularly concerning chest wall contribution.
- Findings provide valuable insights into pediatric respiratory physiology and biomechanics.
Abstract:
The mechanical behavior of the lung and chest wall has not been determined in preschool children. We therefore obtained static expiratory pressure-volume (P-V) curves of the respiratory system, partitioned into lung and chest wall components using esophageal (Pes) and airway pressure (Paw) registration in 17 anesthetized children (0.2 to 15.5 yr) in the supine and lateral position. From the P-V curves the inspiratory capacity (IC), the chest wall elastance (Ecw), and the maximal compliance of the respiratory system (Crs) and lungs (C(lung)) were calculated and related to growth. At IC (Paw = 30 cm H(2)O), Pes was the same in the two positions: 11 +/- 3 cm H(2)O. In contrast, at end-expiration (Paw = 0), Pes was close to zero in the lateral position, but markedly positive in the supine position (7 +/- 2 cm H(2)O). C(lung) was similar in both positions and increased with growth. Thus, C(lung) in the lateral position (ml/cm H(2)O) = 0.0017 x length(2.26) (cm), r(2) = 0.90. Crs and IC were approximately 20% greater (p /= 0.93) with power functions of length in both positions. Ecw expressed as a fraction of total respiratory system elastance (Ecw/Ers) was 33 +/- 12% in the lateral position and 12 +/- 16% supine (p < 0.001). We conclude that the respiratory mechanics in children correlated closely with body size and showed important differences between the supine and lateral positions.