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Titration of continuous positive airway pressure by the pattern of breathing: Analysis of flow‐volume‐time relationships by a noninvasive computerized system
Author(s) -
Schulze Andreas,
Mädler HansJürgen,
Gehrhardt Bernd,
Schaller Peter,
Gmyrek Dieter
Publication year - 1990
Publication title -
pediatric pulmonology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.866
H-Index - 106
eISSN - 1099-0496
pISSN - 8755-6863
DOI - 10.1002/ppul.1950080207
Subject(s) - medicine , expiration , continuous positive airway pressure , anesthesia , airway , respiratory system , functional residual capacity , lung volumes , respiratory physiology , ventilation (architecture) , positive pressure , work of breathing , cardiology , mechanical ventilation , lung , obstructive sleep apnea , mechanical engineering , engineering
Infants can defend or even dynamically elevate their functional residual capacity with additional respiratory muscle work by retarding early expiratory airflow (V̇) with postinspiration inspiratory muscle activity and/or laryngeal narrowing, or by starting inspiration before expiration to the relaxation volume has been completed. In order to study the effect of continuous positive airway pressure (CPAP) on both phenomena in 23 infants (birthweight 1,746 ± 417 g), we elevated the airway pressure stepwise in 0.2 kPa increments. A computerized bedside flow‐volume (V̇/V) analysis was used for evaluation. In 16 “responders” early expiration braking decreased and “premature inspiratory interruption” was postponed at an “appropriate CPAP level.” The linear segment (relaxation line) of the V̇/V‐loop was lengthened until expiratory time reached a maximum. Elevation of CPAP beyond this level again produced a rapid, shallow pattern, often combined with flow acceleration late in expiration (recruitment of expiratory muscles). In the remaining seven infants (non‐responders) these latter signs of excessive airway pressure already occurred at the lowest CPAP levels applied during the “titration trials.” Respiratory rate without CPAP was different between responders (84 ± 17/min) and non‐responders (46 ± 17/min). This approach for determining the appropriate CPAP level might reduce the risk of respiratory muscle fatigue. Pediatr Pulmonol 1990; 8:96‐103.