No abstract

No abstract

No abstract

Arterial blood studies were performed on 44 premature infants while in atmosphere and greater concentrations of oxygen. Analyses were made for oxygen content, oxygen capacity and hematocrit. Concomitant plethysmographic studies were made on 29 occasions. Results were as follows: 1. Only 25% (7) of the premature infants studied breathed regularly in atmosphere; the remaining individuals breathed with some degree of periodicity (44%) or completely irregularly (30%). 2. As the concentration of oxygen being breathed was raised, then more of the group shifted to a regular type of respiration until when in 75-85% oxygen, 88% of the group then breathed with a regular type of respiration. 3. a. The percentage arterial oxygen saturation of the group averaged 93% in atmosphere, 96% in 30-55% oxygen, 100% saturation in 70-79% oxygen being breathed and 102% in 80-89% oxygen. b. In atmosphere, when compared on age basis, the younger group (1-14 days) had essentially the same arterial oxygen saturation as the older group (14-65 days). In an atmosphere of 70-90% oxygen, the saturation of the younger group increased to 102% while the older group rose to 100%. c. When compared on body weight basis, the 0.9-1.3 kg. group increased the arterial oxygen saturation of 85% in atmosphere to 102% when 70-85% oxygen was administered; the 1.3-1.8 kg. group, 93% to 101%; the 1.8-2.3 kg. group, 9% to 100%. (It is noted that either on age or body weight basis the group with higher hematocrit attained higher arterial oxygen saturation when 70-85% oxygen was administered than the group with lower hematocrit.) 4. a. A statistical analysis of the respiratory records revealed an average rise of 30% in minute volume when 30-40% oxygen was administered, this rise being significantly maintained as higher concentrations (to 90%) of oxygen were administered. b. An average significant rise in respiratory rate of 30% was noted when 30-40% oxygen was administered which slowly fell to the original rate level as oxygen administered was increased to 80-90% concentration. c. Consequently, the tidal volume (volume per respiration) gradually increased to 30% above the level in atmosphere as oxygen administered was increased to 80-90% concentration.

No abstract

No abstract

No abstract

No abstract