| 特集名 | モニタリング機器をどう取り扱うか -- 原理と応用・注意点 | |
|---|---|---|
| 題名 | 透析コンソール関係 (4) 温度モニタ，電気伝導率モニタ | |
| 発刊年月 | 2002年 09月 | |
| 著者 | 坂下 惠一郎 | 増子記念病院臨床工学課・臨床工学技士 |
| 【 要旨 】 | 温度および電気伝導率のモニタリングは，血液透析を安全かつ快適に行ううえで不可欠である． 温度センサには，サーミスタや白金測温抵抗体が用いられ，コンソールには透析液温度の制御用と表示・監視用の二つが組み込まれている．透析液温度は，通常33～40℃で制御される．しかし，制御不良などで41℃を超えると監視用温度センサの感知により，ヒータ電源が遮断され透析液の供給を停止し，溶血を防止する．温度センサの配線は細いリード線のため，保守点検作業中に断線を起こす危険性があるので注意を要する． 電気伝導率のモニタリングでは，透析液濃度を連続的に監視しなければならず，電極は流通型で，信頼性を高めるために3極法が用いられている．正常な透析液電導率は，13.5～14.0mS/cmで，16.0mS/cmを超えると高Na血症や高血圧症の起こる危険性があり，13.0mS/cm未満では低Na血症や低血圧症が発症しやすくなり，8.0mS/cm未満では溶血が起こる．電気伝導度が設定正常範囲外になると安全機構が働き，ダイアライザへの透析液供給が停止される．電気伝導率センサの電極は，汚れなどにより抵抗が変化するので定期的な較正や洗浄が必要となる． |
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| Theme | How To Use Monitoring Machines | |
|---|---|---|
| Title | Thermal monitor, electrical conductivity monitor | |
| Author | Keiichiro Sakashita | Clinical Engineering Technologist, Masuko Memorial Hospital |
| [ Summary ] | The monitoring of temperature and electrical conductivity are indispensable to the safety and comfort of those undergoing hemodialysis therapy. Thermistors and platinum resistance thermometers are used as temperature sensors. Two temperature sensors used for the control of dialysate temperature and the display/watch of one are incorporated into the console. Dialysate temperature is generally controlled in the 33 - 40 Cel. range. When the temperature sensor detects temperature over 41 Cel. in the dialysate, heater operation and the supply of dialysate are stopped, in order to prevent hemolysis. Attention to these conditions is necessary because the wiring in the temperature sensor is in danger, of being broken, due to thin lead lines which may be damaged during maintenance work. In cases which monitoring of electrical conductivity is used to continuously monitor dialysate concentrations, the circulation type and the three pole method are used. The electrical conductivity of normal dialysate is 13.5 - 14.0mS/cm. When the electrical conductivity exceeds 16.0mS/cm, there is danger of hypernatremia or/and hypertension. At rates of less than 13.0mS/cm, it is easy for hyponatremia or/and hypotension to occur. At rates below 8.0mS/cm, hemolysis may occur. When electrical conductivity falls outside the normal range, the dialysate supply to the dialyzer is stopped. Because of changes in resistance, due to contaminates, the electrode of the electrical conductivity sensor needs to be calibrated and washed regularly. |
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