Biomaterial Database

Work of breathing during constant- and variable-flow nasal continuous positive airway pressure in preterm neonates. 2001

P B Pandit, and S E Courtney, and K H Pyon, and J G Saslow, and R H Habib

University of Medicine and Dentistry of New Jersey/Robert Wood Johnson Medical School, Camden, New Jersey, USA.

BACKGROUND Constant-flow nasal continuous positive airway pressure (NCPAP) often is used in preterm neonates to recruit and maintain lung volume. Physical model studies indicate that a variable-flow NCPAP device provides more stable volume recruitment with less imposed work of breathing (WOB). Although superior lung recruitment with variable-flow NCPAP has been demonstrated in preterm neonates, corroborating WOB data are lacking. OBJECTIVE To measure and compare WOB associated with the use of variable-flow versus constant-flow NCPAP in preterm neonates. METHODS Twenty-four preterm infants who were receiving constant-flow NCPAP (means, SD) and had birth weight of 1024 +/- 253 g, gestational age of 28 +/- 1.7 weeks, age of 14 +/- 13 days, and FIO(2) of 0.3 +/- 0.1 were studied. Variable-flow and constant-flow NCPAP were applied in random order. We measured changes in lung volume and tidal ventilation (V(T)) by DC-coupled/calibrated respiratory inductance plethysmography as well as esophageal pressures at NCPAP of 8, 6, 4, and 0 cm H(2)O. Inspiratory WOB (WOB(I)) and lung compliance were calculated from the esophageal pressure and V(T) data using standard methods. WOB was divided by V(T) to standardize the results. RESULTS WOB(I) decreased at all CPAP levels with variable-flow NCPAP, with a maximal decrease at 4 cm H(2)O. WOB(I) increased at all CPAP levels with constant-flow CPAP. Lung compliance increased at all NCPAP levels with variable-flow, with a relative decrease at 8 cm H(2)O, whereas it increased only at 8 cm H(2)O with constant-flow NCPAP. Compared with constant-flow NCPAP, WOB(I) was 13% to 29% lower with variable-flow NCPAP. CONCLUSIONS WOB(I) is decreased with variable-flow NCPAP compared with constant-flow NCPAP. The increase in WOB(I) with constant-flow NCPAP indicates the presence of appreciable imposed WOB with this device. Our study, performed in neonates with little lung disease, indicates the possibility of lung overdistention at CPAP of 6 to 8 cm H(2)O with the variable-flow device. Further study is necessary to determine the efficacy of variable-flow NCPAP in neonates with significant lung disease and its use over extended periods of time.continuous-flow and variable-flow NCPAP, work of breathing, premature neonates, lung compliance.

UI	MeSH Term	Description	Entries
D007231	Infant, Newborn	An infant during the first 28 days after birth.	Neonate,Newborns,Infants, Newborn,Neonates,Newborn,Newborn Infant,Newborn Infants
D007234	Infant, Premature	A human infant born before 37 weeks of GESTATION.	Neonatal Prematurity,Premature Infants,Preterm Infants,Infant, Preterm,Infants, Premature,Infants, Preterm,Premature Infant,Prematurity, Neonatal,Preterm Infant
D007235	Infant, Premature, Diseases	Diseases that occur in PREMATURE INFANTS.
D008297	Male		Males
D011175	Positive-Pressure Respiration	A method of mechanical ventilation in which pressure is maintained to increase the volume of gas remaining in the lungs at the end of expiration, thus reducing the shunting of blood through the lungs and improving gas exchange.	Positive End-Expiratory Pressure,Positive-Pressure Ventilation,End-Expiratory Pressure, Positive,End-Expiratory Pressures, Positive,Positive End Expiratory Pressure,Positive End-Expiratory Pressures,Positive Pressure Respiration,Positive Pressure Ventilation,Positive-Pressure Respirations,Positive-Pressure Ventilations,Pressure, Positive End-Expiratory,Pressures, Positive End-Expiratory,Respiration, Positive-Pressure,Respirations, Positive-Pressure,Ventilation, Positive-Pressure,Ventilations, Positive-Pressure
D012129	Respiratory Function Tests	Measurement of the various processes involved in the act of respiration: inspiration, expiration, oxygen and carbon dioxide exchange, lung volume and compliance, etc.	Lung Function Tests,Pulmonary Function Tests,Function Test, Pulmonary,Function Tests, Pulmonary,Pulmonary Function Test,Test, Pulmonary Function,Tests, Pulmonary Function,Function Test, Lung,Function Test, Respiratory,Function Tests, Lung,Function Tests, Respiratory,Lung Function Test,Respiratory Function Test,Test, Lung Function,Test, Respiratory Function,Tests, Lung Function,Tests, Respiratory Function
D004867	Equipment Design	Methods and patterns of fabricating machines and related hardware.	Design, Equipment,Device Design,Medical Device Design,Design, Medical Device,Designs, Medical Device,Device Design, Medical,Device Designs, Medical,Medical Device Designs,Design, Device,Designs, Device,Designs, Equipment,Device Designs,Equipment Designs
D005260	Female		Females
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D014939	Work of Breathing	RESPIRATORY MUSCLE contraction during INHALATION. The work is accomplished in three phases: LUNG COMPLIANCE work, that required to expand the LUNGS against its elastic forces; tissue resistance work, that required to overcome the viscosity of the lung and chest wall structures; and AIRWAY RESISTANCE work, that required to overcome airway resistance during the movement of air into the lungs. Work of breathing does not refer to expiration, which is entirely a passive process caused by elastic recoil of the lung and chest cage. (Guyton, Textbook of Medical Physiology, 8th ed, p406)	Breathing Work,Breathing Works