Universidade Federal de São Paulo, Departamento de Pediatria, Disciplina de Gastroenterologia Pediátrica, São Paulo, SP, Brasil.
Arq Gastroenterol. 2022 Jul-Sep;59(3):428-433. doi: 10.1590/S0004-2803.202203000-76.
The Fatigue Rate Index (FRI) is a parameter in anorectal manometry (ARM) to assess sustained voluntary contraction, considering the squeeze pressure and fatigability of the external anal sphincter. It is used in adults to detect fecal incontinence even in patients who present normal squeeze pressures. The FRI in adult patients with functional constipation is similar to controls.
The aim of this study was to evaluate the feasibility and values of FRI in children in relation to the values previously established in adults and comparing children with functional constipation and retentive fecal incontinence to children without retentive fecal incontinence.
This retrospective study evaluated 105 ARM performed from Jan 2014 to Apr 2015. 42 patients were selected (were able to perform a voluntary contraction and had no co-morbidities other than functional constipation). 14 (33.3%) of those collaborated in sustaining contraction for 40 seconds (s), allowing the evaluation of the FRI. Patients with retentive fecal incontinence secondary to functional constipation (n=7, aged 6 to 13 years, six boys) were our interest group. Patients with functional constipation without fecal incontinence (n=7, aged 6 to 13 years, four boys) were considered a reference group. The ARM were performed with a radial eight-channel perfusion catheter (DynamedTM, São Paulo, Brazil) and the FRI was calculated (Proctomaster 6.4) in the first 20 s and overall 40 s of sustained voluntary contraction.
14 of the selected 42 collaborated in sustaining contraction for 40 s, allowing the evaluation of the FRI. In the first 20 s of contraction, the fecal incontinence group showed a significantly higher mean FRI (2.48±1.39 min) compared to the reference group (1.13±0.72 min, P=0.042), which was not observed in the 40 s interval due to less uniform contraction. The anal resting pressure was higher in the fecal incontinence group (76.83 mmHg) than in the reference group (54.13 mmHg), but the statistical study did not reach significance (P=0.051).
The FRI is feasible in children. The mean FRI obtained in this study is lower than the reported in constipated adults. The mean FRI among children with functional constipation and retentive fecal incontinence is higher than among constipated children without retentive fecal incontinence.
疲劳率指数（FRI）是肛门直肠测压（ARM）中的一个参数，用于评估外括约肌的持续自主收缩能力，考虑到收缩压力和疲劳度。它在成年人中用于检测粪便失禁，即使在收缩压力正常的患者中也是如此。功能性便秘患者的 FRI 与对照组相似。
本研究旨在评估 FRI 在儿童中的可行性和价值，同时与成人中已建立的标准进行比较，并比较功能性便秘和直肠潴留性粪便失禁患儿与无直肠潴留性粪便失禁患儿的 FRI 值。
本回顾性研究评估了 2014 年 1 月至 2015 年 4 月期间进行的 105 次 ARM。选择了 42 名患者（能够进行自主收缩，且除功能性便秘外无其他合并症）。其中 14 名（33.3%）患者能够持续收缩 40 秒，从而可以评估 FRI。有直肠潴留性粪便失禁的功能性便秘患者（n=7，年龄 6 至 13 岁，男孩 6 名）为我们的感兴趣组。功能性便秘且无粪便失禁的患者（n=7，年龄 6 至 13 岁，男孩 4 名）作为对照组。使用径向八通道灌注导管（DynamedTM，巴西圣保罗）进行 ARM，在持续自主收缩的前 20 秒和 40 秒内计算 FRI（Proctomaster 6.4）。
在选定的 42 名患者中，有 14 名能够持续收缩 40 秒，从而可以评估 FRI。在收缩的前 20 秒内，粪便失禁组的平均 FRI（2.48±1.39 min）显著高于对照组（1.13±0.72 min，P=0.042），而在 40 秒间隔内由于收缩不均匀，该差异并不明显。粪便失禁组的静息压（76.83 mmHg）高于对照组（54.13 mmHg），但统计学分析未达到显著水平（P=0.051）。
FRI 在儿童中是可行的。本研究获得的平均 FRI 低于便秘成年人的报道值。功能性便秘伴直肠潴留性粪便失禁儿童的平均 FRI 高于无直肠潴留性粪便失禁的便秘儿童。
