B. Ohare et al., ACUTE LUNG INJURY AFTER INSTILLATION OF HUMAN BREAST-MILK OR INFANT FORMULA INTO RABBITS LUNGS, Anesthesiology, 84(6), 1996, pp. 1386-1391
Background: Recent interest In shortening the fasting interval after i
ngestion of milk products demonstrated large volumes of breast milk in
the stomach 2 h after breastfeeding, Although aspiration is a rare ev
ent, if it were to occur with human breast milk, it is important to un
derstand the extent of the lung injury that might occur. Therefore, th
e response to Instillation of acidified breast milk and Infant formula
in the lungs of adult rabbits was studied. Methods: In 18 anesthetize
d adult rabbits, 1 of 3 fluids (in a volume of 0.8 ml . kg(-1) and PH
level of 1.8, acidified with hydrochloric acid); saline, breast milk,
or infant formula (SMA, Wyeth, Windsor, Ontario), was instilled into t
he lungs via a tracheotomy. The lungs were ventilated for 4 h after in
stillation. Alveolar-to-arterial oxygen gradient and dynamic complianc
e were measured before and at hourly intervals after instillation. Aft
er 4 h, the rabbits were killed and the lungs were excised. Neutrophil
Infiltration was quantitated by a pathologist blinded to the instille
d fluid. a histologic control group of four rabbits was ventilated und
er study conditions without any intratracheal fluid instillation. Resu
lts: Alveolar-to-arterial oxygen gradient increased and dynamic compli
ance decreased significantly during the 4 h after instillation of both
breast milk and infant formula compared with baseline measurements an
d with saline controls (P < 0.05). The neutrophil counts in the lungs
from the saline, breast milk, and formula rabbits were significantly g
reater than those in the control group. Conclusions: Instillation of a
cidified breast milk or infant formula (in a volume of 0.8 ml . kg(-1)
and pH level of 1.8) into rabbits' lungs induces acute lung injury of
similar intensity that lasts at least 4 h.