Poulton B B, Foubert L, Klinowski J, Latimer R D, Knowles P R, Vuylsteke A
Department of Anaesthesia, Papworth Hospital, Cambridge.
Br J Anaesth. 1996 Oct;77(4):534-6. doi: 10.1093/bja/77.4.534.
Nitric oxide (NO) is effective in the management of pulmonary hypertension and shunt-related hypoxia. Nitrogen dioxide (NO2) is formed when the gas is delivered with oxygen. Both oxides of nitrogen have well recognized adverse effects. The scavenging properties of several forms of soda lime have been investigated. A gas flow containing NO 70 ppm and NO2 5 ppm in oxygen was introduced into a vertically mounted Waters' canister containing: (i) 125 g of molecular sieve 5A (a calcium aluminosilicate zeolite) and (ii) 135 g of soda lime containing a potassium permanganate marker. NO and NO2 concentrations were measured at hourly intervals at the entry and exit points using an electrochemical analyser. Extraction ratios (gradient/ inlet x 100) were calculated for a 24-h period. High extraction ratios (in excess of 90%) of NO and NO2 were observed with both compounds for up to 1 h but these declined rapidly after this time with soda lime. In contrast, the molecular sieve produced extraction ratios in excess of 98% for both gases over the 24-h period. We conclude that the molecular seive 5A is a highly effective scavenger of NO and NO2.
一氧化氮（NO）在治疗肺动脉高压和分流相关性低氧血症方面有效。当该气体与氧气一同输送时会形成二氧化氮（NO₂）。两种氮氧化物都具有公认的不良影响。已对几种形式的碱石灰的清除特性进行了研究。将一种在氧气中含有70 ppm NO和5 ppm NO₂的气流引入一个垂直安装的沃特斯罐中，该罐中装有：（i）125克5A分子筛（一种钙铝硅酸盐沸石）和（ii）135克含有高锰酸钾标记物的碱石灰。使用电化学分析仪每小时在入口和出口点测量NO和NO₂的浓度。计算24小时期间的提取率（梯度/入口×100）。两种化合物在长达1小时的时间内对NO和NO₂均观察到高提取率（超过90%），但此后使用碱石灰时提取率迅速下降。相比之下，在24小时期间，分子筛对两种气体的提取率均超过98%。我们得出结论，5A分子筛是NO和NO₂的高效清除剂。
