Gibbs C P, Schwartz D J, Wynne J W, Hodd C I, Kuck E J
Anesthesiology. 1979 Nov;51(5):380-5. doi: 10.1097/00000542-197911000-00003.
The amount of damage resulting from pulmonary aspiration of gastric contents is determined primarily by the acidity of the aspirate. Thus, it has been recommended that the pH of stomach contents of pregnant women be increased by the oral administration of antacids prior to anesthesia for delivery. This study was done to investigate the effects of antacid aspiration in dogs and compare these effects with those obtained by trials of aspiration of acid, saline solution, and alkaline saline solution. Mean PaO2 of the saline-treated group had decreased from 81 to 60 torr at 10 min, while that of the alkaline saline-treated group had decreased from 83 to 58 torr. Fractional intrapulmonary physiologic shunt (Qs/Qt) increased in these two groups, from 15 to 34 and from 16 to 42 per cent, respectively. The Qs/Qt had returned to control values in both groups by four hours, and the PaO2 had returned to control values by 24 hours. By contrast, the acid- and antacid-treated groups had decreases in PaO2 values from 77 to 34 torr and from 84 to 46 torr, respectively. Neither group had a return of PaO2 to pre-aspiration level by 24 hours. Likewise, the Qs/Qt increased significantly more in these two groups: 14 to 66 per cent in the acid-treated group and 13 to 47 per cent in the antacid-treated group. These changes persisted throughout four hours. The saline and alkaline saline aspirates produced little histologic damage. The acid aspirate produced hemorrhage, exudates, and edema. However, these changes were no longer present a month later. The antacid aspirate produced a marked bronchopneumonia that was still present as a chronic inflammatory reaction after a month. These findings indicate that antacids can cause pulmonary damage when aspirated.
胃内容物肺吸入造成的损害程度主要取决于吸入物的酸度。因此，有人建议在分娩麻醉前通过口服抗酸剂来提高孕妇胃内容物的pH值。本研究旨在调查抗酸剂吸入对犬的影响，并将这些影响与酸、盐溶液和碱性盐溶液吸入试验的结果进行比较。盐水处理组的平均动脉血氧分压（PaO2）在10分钟时从81 torr降至60 torr，而碱性盐水处理组的平均动脉血氧分压从83 torr降至58 torr。这两组的肺内生理性分流分数（Qs/Qt）分别从15%增加到34%和从16%增加到42%。两组的Qs/Qt在4小时时均恢复到对照值，PaO2在24小时时恢复到对照值。相比之下，酸处理组和抗酸剂处理组的PaO2值分别从77 torr降至34 torr和从84 torr降至46 torr。两组在24小时时PaO2均未恢复到吸入前水平。同样，这两组的Qs/Qt增加更为显著：酸处理组从14%增加到66%，抗酸剂处理组从13%增加到47%。这些变化在4小时内持续存在。盐水和碱性盐水吸入造成的组织学损伤很小。酸吸入导致出血、渗出物和水肿。然而，一个月后这些变化不再存在。抗酸剂吸入导致明显的支气管肺炎，一个月后仍表现为慢性炎症反应。这些发现表明，抗酸剂吸入时可导致肺部损伤。
