Department of Nutrition and Food Services, Royal Children's Hospital, Parkville, Victoria, Australia.
JPEN J Parenter Enteral Nutr. 2011 Jul;35(4):540-4. doi: 10.1177/0148607110383285. Epub 2011 May 27.
Enteral feeding is a common method of nutrition support when oral intake is inadequate. Confirmation of correct nasogastric (NG) tube placement is essential. Risks of morbidity/mortality associated with misplacement in the lung are well documented. Studies indicate that pH ≤ 4 confirms gastric aspirate, but in pediatrics, a pH of gastric aspirate is often >4. The goal of this study was to determine a reliable and practical pH value to confirm NG tube placement, without increasing the risk of not identifying a misplaced NG tube.
Pediatric inpatients older than 4 weeks receiving enteral nutrition (nasogastric or gastrostomy) were recruited over 9 months. Aspirate samples were pH tested at NG tube placement and before feedings. If pH >4, NG tube position was confirmed by chest radiograph or further investigations. In addition, intensive care unit (ICU) patients who required endotracheal suctioning were recruited, and endotracheal aspirate samples were pH tested.
A total of 4,330 gastric aspirate samples (96% nasogastric) were collected from 645 patients with a median (interquartile range [IQR]) age of 1.0 years (0.3-5.2 years). The mean (standard deviation [SD]) pH of these gastric samples was 3.6 (1.4) (range, 0-9). pH was >4 in 1,339 (30.9%) gastric aspirate samples, and of these, 244 were radiographed, which identified 10 misplaced tubes (1 with pH 5.5). A total of 65 endotracheal aspirate samples were collected from 19 ICU patients with a median (IQR) age of 0.6 years (0.4-5.2 years). The mean (SD) pH of these samples was 8.4 (0.8) (range, 6-9.5).
Given that the lowest pH value of endotracheal aspirate sample was 6, and a misplaced NG tube was identified with pH 5.5, it is proposed that a gastric aspirate pH ≤ 5 is a safer, reliable, and practical cutoff in this population.
当口服摄入不足时，肠内喂养是一种常见的营养支持方法。确认鼻胃管（NG）正确放置至关重要。将其误置于肺部会导致发病率/死亡率增加，这一点已有充分的记录。研究表明，pH 值≤4 可确认胃抽吸物，但在儿科中，胃抽吸物的 pH 值通常>4。本研究的目的是确定一个可靠且实用的 pH 值来确认 NG 管的位置，同时不增加无法识别误置 NG 管的风险。
在 9 个月的时间里，招募了年龄超过 4 周、接受肠内营养（鼻胃管或胃造口术）的儿科住院患者。在 NG 管放置和喂养前对抽吸样本进行 pH 值测试。如果 pH 值>4，则通过胸部 X 光或进一步检查确认 NG 管的位置。此外，还招募了需要气管内吸引的重症监护病房（ICU）患者，并对气管内抽吸样本进行 pH 值测试。
共收集了 645 名患者的 4330 个胃抽吸样本（96%为鼻胃管），中位数（四分位距 [IQR]）年龄为 1.0 岁（0.3-5.2 岁）。这些胃样本的平均（标准差 [SD]）pH 值为 3.6（1.4）（范围，0-9）。pH 值>4 的胃抽吸样本有 1339 个（30.9%），其中 244 个进行了 X 光检查，发现 10 个位置不当的管（1 个 pH 值为 5.5）。从 19 名 ICU 患者中收集了 65 个气管内抽吸样本，中位数（IQR）年龄为 0.6 岁（0.4-5.2 岁）。这些样本的平均（SD）pH 值为 8.4（0.8）（范围，6-9.5）。
鉴于气管内抽吸样本的最低 pH 值为 6，且 pH 值为 5.5 时可识别出误置的 NG 管，因此建议在该人群中，胃抽吸 pH 值≤5 是一种更安全、可靠且实用的界限值。
