BACKGROUND & AIMS Abnormal acid exposure time (AET) is associated with good outcomes of symptoms from antireflux therapy. Low esophageal mean nocturnal baseline impedance (MNBI) is an additional marker of reflux disease. We aimed to evaluate the value of MNBI when analysis of AET produces borderline or inconclusive results. METHODS We studied a retrospective cohort of 371 patients (mean age, 54.5 ± 0.7 y; 60.0% female) who had persistent reflux symptoms after treatment and underwent ambulatory pH-impedance monitoring off antisecretory therapy at 1 tertiary center in Europe or 1 in the United States. Total AET was determined from pH impedance studies (pathologic, >6%; physiologic, <4%; borderline or inconclusive, 4%-6%). Baseline impedance values were calculated at the 5-cm impedance channel at 3 nocturnal 10-minute periods and averaged to yield MNBI (abnormal, <2292 ohms). The primary outcome was response to antireflux therapy, defined as global symptom improvement of 50% or greater on patients' answers on standardized visual analog scales. RESULTS Among the 371 patients, 107 (28.8%) had pathologic AET and 234 (63.1%) had abnormal MNBI. Low MNBI was concordant in 99.1% of patients with pathologic AET, in 91.2% with borderline AET, and in 33.7% with physiologic AET. During 38.7 ± 0.8 months of follow-up evaluation, 43.0% of patients had improved symptoms with medical therapy and 76.2% had improved symptoms with surgical antireflux therapy (P < .0001). When MNBI was low, response to medical therapy did not differ significantly between patients with borderline AET and patients with pathologic AET (P = .44), but did differ significantly when each group was compared with patients with physiologic AET, regardless of whether MNBI was normal or low (P < .0001 for each comparison). CONCLUSIONS When low, MNBI identifies patients with pathologic and borderline AET who respond to antireflux therapy. MNBI analysis complements AET in defining esophageal reflux burden. MNBI correlates with response of symptoms to antireflux therapy.

中文翻译：

---

当食管反流监测酸暴露时间不确定时，平均夜间基线阻抗与症状结果相关。

背景和目的 异常酸暴露时间 (AET) 与抗反流治疗症状的良好结果相关。低食管平均夜间基线阻抗 (MNBI) 是反流病的另一个标志。我们旨在评估当 AET 分析产生临界或不确定结果时 MNBI 的价值。方法 我们研究了 371 名患者（平均年龄，54.5 ± 0.7 岁；60.0% 女性）的回顾性队列，这些患者在治疗后有持续的反流症状，并在欧洲 1 家三级中心或美国 1 家停止抗分泌治疗后接受动态 pH 阻抗监测。州。总 AET 由 pH 阻抗研究确定（病理性，>6%；生理性，<4%；临界或不确定，4%-6%）。基线阻抗值是在 3 个夜间 10 分钟时段在 5 厘米阻抗通道处计算的，并取平均值以产生 MNBI（异常，<2292 欧姆）。主要结果是对抗反流治疗的反应，定义为患者在标准化视觉模拟量表上的回答总体症状改善 50% 或更多。结果 371例患者中，107例（28.8%）有病理性AET，234例（63.1%）有异常MNBI。99.1% 的病理性 AET 患者、91.2% 的临界 AET 患者和 33.7% 的生理性 AET 患者的低 MNBI 是一致的。在 38.7 ± 0.8 个月的随访评估中，43.0% 的患者接受药物治疗后症状改善，76.2% 接受手术抗反流治疗后症状改善（P < .0001）。当 MNBI 较低时，交界性 AET 患者和病理性 AET 患者对药物治疗的反应没有显着差异（P = .44），但当每组与生理性 AET 患者进行比较时，无论 MNBI 是正常还是低，确实存在显着差异（P < .0001 对于每个比较）。结论 当低时，MNBI 可识别出对抗反流治疗有反应的病理性和临界 AET 患者。MNBI 分析在定义食管反流负担方面补充了 AET。MNBI 与症状对抗反流治疗的反应相关。MNBI 可识别对抗反流治疗有反应的病理性和临界 AET 患者。MNBI 分析在定义食管反流负担方面补充了 AET。MNBI 与症状对抗反流治疗的反应相关。MNBI 可识别对抗反流治疗有反应的病理性和临界 AET 患者。MNBI 分析在定义食管反流负担方面补充了 AET。MNBI 与症状对抗反流治疗的反应相关。