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Physiological basis of poorer respiratory outcomes for males following preterm birth
Author(s) -
Harding Richard,
Ishak Noreen,
Hanita Takushi,
Sozo Foula,
De Matteo Robert
Publication year - 2012
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.26.1_supplement.712.3
Subject(s) - medicine , betamethasone , gestational age , pulmonary compliance , arterial blood , gestation , respiratory system , fetus , lung , pco2 , anesthesia , obstetrics , pregnancy , physiology , biology , genetics
Our aim was to identify the physiological basis for the “male disadvantage” in respiratory function in preterm infants, using an ovine model of preterm birth in which survival of males is less than in males. At ~125 days of gestation (DGA; term ~147DGA), fetal sheep underwent preparatory surgery. Ewes received lowdose betamethasone (5.7mg i.m.) at 131DGA. At 133DGA, lambs were delivered via caesarean section and were studied for 8 hours with no ventilatory support. Arterial and intrapleural pressures were recorded continuously and arterial blood was sampled every 15min. Lambs were then euthanized for static lung compliance measurement. At 6–8h after preterm birth, males had significantly lower arterial pH and higher PaCO 2 than females (p<0.05). No differences were observed in lactate, glucose and mean arterial pressure. Static lung compliance was 30% lower in males than in females (p=0.012). There was a positive correlation between static lung compliance and mean pH (from 6–8h) and a negative correlation with mean PaCO 2 (both p<0.05). Male preterm lambs have stiffer lungs than females at the same gestational age, leading to CO 2 retention and acidemia, and is the likely cause of the “male disadvantage”. The lower lung compliance of males is likely a result of differences in surfactant composition. Funding was provided by the National Health and Medical Research Council of Australia.