Blood volume and haematocrit studies in respiratory distress syndrome of the newborn.

The observation that a raised venous pressure appears to be of benefit to newborn babies with respiratory distress (Bonham Carter, Bound, and Smellie, 1956) led Bound, Harvey, and Bagshaw (1962) to assess the effect of delayed clamping of the umbilical cord of premature babies. In that investigation it was concluded that the placental transfusion was responsible for the lower incidence of respiratory distress in those premature babies where clamping of the cord was delayed. It occurred to us that these observations might have a common basis in some abnormality of the blood volume in those babies who develop the respiratory distress syndrome (RDS). While we were studying a therapeutic approach to RDS (Hutchison, Kerr, Douglas, Inall, and Crosbie, 1964), we took the opportunity to measure the blood volumes of 17 babies. A group of 20 normal premature babies was also studied by the same technique. This paper describes the results of these studies. The criteria previously described for the diagnosis of severe idiopathic respiratory distress (Hutchison et al., 1964) were common to all cases. These were (1) respiratory grunting; (2) tachypnoea over 60 per minute after the first hour; (3) marked and persistent sternal, subcostal, and intercostal recession during inspiration; (4) cyanosis when breathing air; and (5) characteristic radiographic changes, i.e. diffuse reticulogranular mottling in the lung fields and an 'air bronchogram'.