Volume delivery during positive pressure inflation--relationship to spontaneous tidal volume of neonates.
Volume delivery by positive pressure inflation was determined in 20 premature infants and 10 infants born at term on days 1 and 2. The spontaneous tidal volume, respiratory rate and inspiratory to expiratory (I:E) ratio were measured daily in the first week of life in an additional group of 20 infants born prematurely. Measurements were made using a pneumotachograph only when the infants were stable and had acceptable blood gases for at least 2 h. There was variability between individuals but the median delivered volume by positive pressure ventilation ranged between 4.9 and 6.1 ml/kg on days 1 and 2 and within the groups of different maturity. There was no significant difference in the results of infants born prematurely or at term or when studied on days 1 or 2. The median spontaneous tidal volume during the first week of life varied between 5.4 and 6.7 ml/kg; respiratory rate between 72 and 80 breaths/min and I:E ratio from 0.67 to 0.77. Postnatal age had no significant effect on the results. These results suggest volume delivery by positive pressure inflation during a stable period of ventilation is similar to the spontaneous tidal volume.
Dimitriou
G
G
Department of Child Health, King's College Hospital, London, UK.
Greenough
A
A
Chan
V
V
D005540:Forced Expiratory Flow Rates; D005865:Gestational Age; D006801:Humans; D007231:Infant, Newborn; D007234:Infant, Premature / Q000502:physiology*; D007320:Inspiratory Capacity; D011175:Positive-Pressure Respiration; D012016:Reference Values; D012119:Respiration; D013990:Tidal Volume