Relation between partial and raised volume forced expiratory flows in sick infants

Area of Science:

• Pediatric Pulmonology
• Respiratory Physiology

Background:

• Maximal expiratory flow-volume (MEFV) and partial expiratory flow-volume (PEFV) maneuvers are used to assess infant lung function.
• MEFV maneuvers offer more variables than PEFV, which provides only maximal flow at functional residual capacity (Vmax FRC).

Purpose of the Study:

• To compare Vmax FRC values from PEFV maneuvers with flows at low lung volumes obtained from MEFV maneuvers in infants with various illnesses.
• To determine the interchangeability of MEFV and PEFV maneuvers for infant lung function testing.

Main Methods:

• Retrospective analysis of records from 175 infants (2-234 weeks old) treated at a tertiary outpatient clinic.
• Comparison of PEFV-derived Vmax FRC with MEFV-derived flow variables using linear regression and Bland-Altman plots.

Main Results:

• Vmax FRC showed high correlation with forced expiratory flow at 85% of forced vital capacity (FEF85; r=0.87) and at 75% (FEF75; r=0.83).
• Agreement between Vmax FRC and FEF85/FEF75 was consistent when analyzed as z-scores.
• Less agreement was observed with forced expired volume in 0.5 sec (FEV0.5).

Conclusions:

• Both PEFV and MEFV maneuvers demonstrate high agreement in assessing small airway function in sick infants.
• The findings suggest that Vmax FRC (from PEFV) and FEF85/FEF75 (from MEFV) are comparable and potentially interchangeable for evaluating infant lung function.