Mela G S, Savarino V, Moretti M, Sumberaz A, Bonifacino G, Zentilin P, Caputo E, Villa G, Celle G
Cattedra di Clinica Medica R, Università di Genova, Italy.
Dig Dis Sci. 1990 Dec;35(12):1473-81. doi: 10.1007/BF01540564.
Antimony and glass pH electrodes show almost identical experimental errors in continuously measuring buffer solutions at constant temperature over 24 hr. These errors are lower than the nominal quantization error of the instruments and are not properly described by the 24-hr drift determination. The addition of food particles to the solutions can induce severe reading artifacts. The longer response time reported in vitro of antimony electrodes when moving from pH 1 to pH 7 (3.4 sec vs 0.8 sec with glass electrodes) is irrelevant during in vivo pH-metry studies, because we found that the greatest absolute difference between raw fast acquired (4-6 sec) consecutive pH readings of two commonly used devices was 0.7 pH units in circadian profiles obtained from 413 subjects with various clinical conditions. In our in vivo studies, gastric acidity was monitored continuously with two side-by-side minielectrodes, which were variously combined (antimony-glass, A-G; antimony-antimony A1-A2; glass-glass, G1-G2) and applied on groups of 27 subjects matched for clinical condition. The 24-hr pH means and the 24-hr [H+] means calculated from the acidity profiles obtained with the three electrode combinations, lie on the identity line in each group. Using the Bland-Altman technique for assessing measurement agreement, the differences between the 24-hr pH means and the 24-hr [H+] means obtained with the three combined systems are similar (P = .903 and P = 0.824, respectively) and their 95% confidence limits are comprised within the range (+/-) of the reading error of the measuring systems (namely, +/- 0.3 pH units and +/- 12 mmol/liter in terms of [H+]).(ABSTRACT TRUNCATED AT 250 WORDS)
锑电极和玻璃pH电极在恒温连续测量缓冲溶液24小时的实验中显示出几乎相同的误差。这些误差低于仪器的标称量化误差，并且不能通过24小时漂移测定得到恰当描述。向溶液中添加食物颗粒会导致严重的读数伪影。体外研究报道，从pH 1移动到pH 7时，锑电极的响应时间更长（3.4秒，而玻璃电极是0.8秒），但在体内pH测量研究中这并不重要，因为我们发现，在413名患有各种临床病症的受试者的昼夜节律曲线中，两种常用设备快速获取的原始连续pH读数（4 - 6秒）之间的最大绝对差值为0.7个pH单位。在我们的体内研究中，用两个并排的微型电极连续监测胃酸度，电极有不同组合（锑 - 玻璃，A - G；锑 - 锑，A1 - A2；玻璃 - 玻璃，G1 - G2），并应用于27名临床情况匹配的受试者组。由三种电极组合获得的酸度曲线计算出的24小时pH平均值和24小时[H⁺]平均值，在每组中都位于恒等线上。使用Bland - Altman技术评估测量一致性，三种组合系统获得的24小时pH平均值和24小时[H⁺]平均值之间的差异相似（分别为P = 0.903和P = 0.824），其95%置信区间包含在测量系统读数误差范围内（即[H⁺]方面为±0.3个pH单位和±12 mmol/L）。（摘要截断于250字）
