Savarino V, Mela G S
ISMI, Cattedra di Gastroenterologia, Università di Genova, Italy.
Dig Dis. 1990;8 Suppl 1:23-30. doi: 10.1159/000171276.
In an attempt to eliminate the noise affecting continuous 24-hour intragastric pH metry curves in order to obtain a more appropriate identification of hourly intraluminal pH values to which the corresponding aspirate ones were compared, the raw data of one of our previous experiments were treated using a smoothing technique (removal of noise peaks was followed by moving averages on three adjacent points, 1 min apart, which were applied both singly and combined with Fourier's filtration employing the first 32 harmonics) A gradual improvement of all parameters of regression analysis from original data to those achieved with the two above-mentioned methods was found. In particular, the regression coefficient r increased from 0.83 to 0.88 with the singly moving averages technique and even to 0.95 when Fourier's filtration was combined. Both techniques provided also similar improvement as far as slope and elevation values were concerned: the slope was almost equal to 1 and the elevation was very low, so that paired data might be assumed to be proportional. It can be concluded that hourly pH values of continuous intraluminal monitoring and those of simultaneous gastric aspiration appear better correlated if the elimination of noise disturbing the in vivo pH metry curves is obtained. With regard to this, the use of a combined smoothing-filtering technique, such as moving averages plus Fourier's filtration after removal of the noise peaks, seems a very advantageous modality.
为了消除影响连续24小时胃内pH值测量曲线的噪声，以便更准确地识别与之比较的相应吸出物的每小时管腔内pH值，我们对之前一项实验的原始数据采用了一种平滑技术进行处理（先去除噪声峰值，然后对相隔1分钟的三个相邻点进行移动平均，该操作单独进行，并与采用前32个谐波的傅里叶滤波相结合）。结果发现，从原始数据到上述两种方法所得到的数据，回归分析的所有参数都有逐步改善。特别是，采用单独的移动平均技术时，回归系数r从0.83提高到0.88，当与傅里叶滤波结合时，甚至提高到0.95。就斜率和截距值而言，这两种技术也都有类似的改善：斜率几乎等于1，截距非常低，因此可以认为配对数据是成比例的。可以得出结论，如果能够消除干扰体内pH值测量曲线的噪声，连续管腔内监测的每小时pH值与同时进行的胃吸出物pH值之间的相关性会更好。就此而言，使用一种组合的平滑-滤波技术，如在去除噪声峰值后进行移动平均加傅里叶滤波，似乎是一种非常有利的方式。
