O'Hare B, Lerman J, Endo J, Cutz E
Department of Anaesthesia, Hospital for Sick Children, Toronto, Ontario, Canada.
Anesthesiology. 1996 Jun;84(6):1386-91. doi: 10.1097/00000542-199606000-00015.
Recent interest in shortening the fasting interval after ingestion of milk products demonstrated large volumes of breast milk in the stomach 2 h after breastfeeding. Although aspiration is a rare event, if it were to occur with human breast milk, it is important to understand the extent of the lung injury that might occur. Therefore, the response to instillation of acidified breast milk and infant formula in the lungs of adult rabbits was studied.
In 18 anesthetized 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 the lungs via a tracheotomy. The lungs were ventilated for 4 h after instillation. Alveolar-to-arterial oxygen gradient and dynamic compliance were measured before and at hourly intervals after instillation. After 4 h, the rabbits were killed and the lungs were excised. Neutrophil infiltration was quantitated by a pathologist blinded to the instilled fluid. A histologic control group of four rabbits was ventilated under study conditions without any intratracheal fluid instillation.
Alveolar-to-arterial oxygen gradient increased and dynamic compliance decreased significantly during the 4 h after instillation of both breast milk and infant formula compared with baseline measurements and with saline controls (P < 0.05). The neutrophil counts in the lungs from the saline, breast milk, and formula rabbits were significantly greater than those in the control group.
Instillation of acidified 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.
近期对于缩短摄入奶制品后的禁食间隔的研究表明，母乳喂养后2小时胃内会有大量母乳。尽管误吸是罕见事件，但如果发生在人乳误吸的情况下，了解可能发生的肺损伤程度很重要。因此，研究了成年兔肺内滴注酸化母乳和婴儿配方奶粉后的反应。
在18只麻醉的成年兔中，通过气管切开术将3种液体中的1种（体积为0.8 ml·kg-1，pH值为1.8，用盐酸酸化）；生理盐水、母乳或婴儿配方奶粉（惠氏公司的SMA，安大略省温莎市）滴入肺内。滴注后对肺进行4小时通气。在滴注前和滴注后每小时测量肺泡-动脉氧梯度和动态顺应性。4小时后，处死兔子并切除肺。由对滴注液体不知情的病理学家对中性粒细胞浸润进行定量分析。4只兔子的组织学对照组在研究条件下进行通气，不进行任何气管内液体滴注。
与基线测量值和生理盐水对照组相比，滴注母乳和婴儿配方奶粉后的4小时内，肺泡-动脉氧梯度显著增加，动态顺应性显著降低（P < 0.05）。生理盐水组、母乳组和配方奶粉组兔子肺内的中性粒细胞计数显著高于对照组。
向兔肺内滴注酸化母乳或婴儿配方奶粉（体积为0.8 ml·kg-1，pH值为1.8）会引发强度相似的急性肺损伤，且至少持续4小时。
