Document Detail

Combined effects of surfactant substitution and prolongation of inspiration phase in artificially ventilated premature newborn rabbits.
MedLine Citation:
PMID:  6760100     Owner:  NLM     Status:  MEDLINE    
Premature newborn rabbits, delivered by hysterotomy on day 27 of gestation, were tracheotomized at birth, kept in body plethysmographs, and subjected to pressure-generated ventilation at a working pressure of 25 cm H2O, 100% O2, and frequency 40/min. Thirty-seven animals received 50 microliters of heterologous surfactant (phospholipid content 40 mg/ml) via the tracheal cannula before onset of artificial ventilation, eight were ventilated with a positive end-expiratory pressure (PEEP) of 6 cm H2O, and 44 served as controls. All animals were ventilated in a randomized sequence of 2-min periods with 20, 40, 60, or 80% inspiration time. After the experiment the trachea was clamped at end-inspiration and the lungs fixed by immersion in formalin. Plethysmograph recordings of tidal volume revealed that lung-thorax compliance was low in control animals, even at inspiration time 80% (mean +/- S.E. = 0.17 +/- 0.03 ml/cm H2O X kg). In animals treated with surfactant or PEEP, compliance was significantly improved at all ventilator settings. The highest mean compliance values, obtained at 60% inspiration time were 0.91 +/- 0.07 and 0.73 +/- 0.14 ml/cm H2O X kg in surfactant- and PEEP-treated animals, respectively. Compliance of surfactant-treated animals was significantly higher than that of PEEP-treated animals at inspiration time 40% (0.85 +/- 0.07 versus 0.52 +/- 0.13 ml/cm H2O X kg; P less than 0.05). The relative volume of the alveolar compartment, determined morphometrically in histologic sections and expressed as the alveolar expansion index (Ia), was significantly higher in surfactant-treated animals than in controls (1.60 +/- 0.12 versus 0.74 +/- 0.06; P less than 0.005), but not improved in animals ventilated with PEEP. In animals receiving surfactant, Ia increased with the duration of the inspiration phase, from 0.99 +/- 0.10 at 20% to 1.95 +/- 0.22 at 80% inspiration time. There was also histologic evidence of enhanced recruitment of aerated alveoli in surfactant-treated animals ventilated with prolonged inspiration time.
B Lachmann; P Berggren; T Curstedt; G Grossmann; B Robertson
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Pediatric research     Volume:  16     ISSN:  0031-3998     ISO Abbreviation:  Pediatr. Res.     Publication Date:  1982 Nov 
Date Detail:
Created Date:  1983-03-11     Completed Date:  1983-03-11     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  0100714     Medline TA:  Pediatr Res     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  921-7     Citation Subset:  IM    
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MeSH Terms
Animals, Newborn / physiology*
Lung / pathology
Lung Compliance / drug effects
Positive-Pressure Respiration*
Pulmonary Surfactants / pharmacology*
Random Allocation
Respiration / drug effects*
Tidal Volume
Reg. No./Substance:
0/Pulmonary Surfactants

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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