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Shape of forced expiratory flow-volume curves in infants

P N Le Souëf1, D M Hughes, L I Landau

  • 1Professorial Department of Thoracic Medicine, Royal Childrens Hospital, Parkville, Victoria, Australia.

The American Review of Respiratory Disease
|September 1, 1988
PubMed

Insights

Partial forced expiratory flow-volume (FEFV) curves in infants can reveal respiratory function. Curve shape and specific flow parameters effectively quantify airway obstruction without needing lung volume correction.

Area of Science:

  • Pediatric Pulmonology
  • Respiratory Physiology
  • Medical Device Technology

Background:

  • Assessing infant respiratory function is challenging due to small lung volumes and cooperation issues.
  • Partial forced expiratory flow-volume (FEFV) curves offer a potential method for evaluating expiratory airflow dynamics.

Purpose of the Study:

  • To investigate the utility of partial FEFV curves in quantifying respiratory function in infants.
  • To determine if curve shape and specific parameters can identify obstructive airway disease.

Main Methods:

  • Partial FEFV curves were generated in 36 infants using an inflatable cuff with varying compression pressures.
  • Respiratory system compliance, conductance, and lung volumes were measured via whole-body plethysmography.
  • Pressure transmission to the pleural space was assessed to standardize compression.

Main Results:

  • Infants with convex partial FEFV curves generally showed better respiratory function than those with concave curves.
  • A combination of concave curves and tidal flow limitation indicated the worst respiratory function.
  • Two parameters, Vm1d(forced/tidal) and Pmin, effectively quantified respiratory function without lung volume correction.

Conclusions:

  • The shape of partial FEFV curves provides valuable information about infant respiratory function.
  • Standardized compression pressures are crucial for reliable partial FEFV curve generation.
  • Specific derived parameters offer a size-independent method for assessing expiratory flow reserve and obstruction.

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