| Japanese |
|---|
| Title | 肺動脈カテーテルの周波数特性の改善方法について |
|---|
| Subtitle | 原著 |
|---|
| Authors | 鈴木利保, 杵淵嘉夫, 福山東雄, 滝口守, 山本道雄 |
|---|
| Authors(kana) | |
|---|
| Organization | 東海大学医学部麻酔科学教室 |
|---|
| Journal | 循環制御 |
|---|
| Volume | 18 |
|---|
| Number | 2 |
|---|
| Page | 242-251 |
|---|
| Year/Month | 1997/ |
|---|
| Article | 原著 |
|---|
| Publisher | 日本循環制御医学会 |
|---|
| Abstract | 「要旨」脱気水をプライミングした肺動脈カテーテル間の周波数特性の優劣を比較し, 長さや太さが同じ条件下では, 肉厚で円形のルーメン構造が薄い隔壁で分割された扇形のルーメン構造より優れた周波数特性を示した. カテーテルを選択ないし設計するときは断面基材のなかに円型のルーメンをなるべく均一に埋め込むように配置した構造にすべきである. 脱気水をプライミングした場合, 円形のルーメンをもつ標準的なカテーテル(7Fr, 4ルーメン, 有効長110cm)の固有周波数と制動係数はそれぞれ40Hz以上, 0.14以下となり, 肺動脈圧波形を忠実に導出しうることをfn-ζチャートで確認した. 他方, 同形のカテーテルを通常の臨床手順で組み立てると固有周波数は1/4以下に, 制動係数系は2倍以上に劣化し, 導出した波形が歪んでいることをfn-ζチャートで確認した. 特性の劣化の原因が溶液中の気泡よることは明らかである. 臨床使用時の周波数特性を劣化させる原因となる微小気泡の発生の防止法について, 臨床への適用が可能な方法を検討した. 微小気泡は溶存していた空気が液温の上昇によって液中に遊離することが原因であることを実証した. パックのまま体温より高い40℃に保温しておくと, 液温が体温まで低下しても微小気泡は発生しない. この方法によって液温の変化に対して安定で, かつ, 固有周波数は2倍以上に改善し, 概ね忠実な波形が得られることを確認した. もう1つの方法は, 二酸化炭素ガスでバブリングすると短時間で溶存空気が排出され, 効率的に脱気処理ができること示した. |
|---|
| Practice | 基礎医学・関連科学 |
|---|
| Keywords | Pulmonary artery catheter, Frequency caracteristics, Natural frequency, Damping coeffiient, Air bubble |
|---|
| English |
|---|
| Title | Practical Considerations for Improving the Dynamic Response of the Conventional Pulmonary Artery Catheter Manometer System |
|---|
| Subtitle | |
|---|
| Authors | Toshiyasu Suzuki, Yoshio Kinefuchi, Haruo Fukuyama, Mamoru Takiguchi, Michio Yamamoto |
|---|
| Authors(kana) | |
|---|
| Organization | Department of Anesthesiology, School of Medicine, Tokai University |
|---|
| Journal | Circulation Control |
|---|
| Volume | 18 |
|---|
| Number | 2 |
|---|
| Page | 242-251 |
|---|
| Year/Month | 1997/ |
|---|
| Article | Original article |
|---|
| Publisher | Japan Society of Circulation Control |
|---|
| Abstract | Frequency characteristic measurements of a fluid-filled catheter-manometer system in deaerated lactated Ringer's solution have revealed that the natural frequency of conventional PAC with circular lumen (7 Fr ; 4 lumina ; 110cm length) exceeds 40Hz, and its damping coefficient is less than 0.14. In comparison with conventional clinical procedures, the former figure is 4 times greater, while the latter is one-half. These values seemed to be closely interrelated to the structure of the lumen. A thick-walled, circular cross-section provided much better frequency characteristics than those provided by a radial cross-section, partitioned with thin walls. Deteriorating frequency characteristics of a system assembled by conventional clinical procedures seemed to be caused by the formation of microscopic bubbles in the lumen, increasing system compliance. Bubbles result from reduction of air solubility, affected by temperature rise from ambient to body temperature of the priming fluid. This phenomenon can be prevented by pre-warming the priming fluid. To verify the above, comparisons were made to determine the natural frequency and damping coefficient on priming methods : (1)Stored at 25 degrees C and then warmed to 37 degrees C, (2) At 40 degrees C then cooled to 37 degrees C. In case one, natural frequency decreased from 16Hz to 13Hz, but in case two, it remained unchanged at 28Hz. Microscopic observation confirmed the appearance of microbubbles after the fluid temperature increased from 25 to 37 degrees C. We also tested the efficacy of a simple method of deaeration, bubbling the priming fluid with carbon dioxide. Substitution of dissolved air with carbon dioxide was assured by continuous monitoring of dissolved oxygen in the fluid. The best results were obtained when fluid temperature was increased to 40 degrees C and allowed to bubble with carbon dioxide for 20 minutes. We found this method time-saving, sterile, and therefore clinically applicable. |
|---|
| Practice | Basic medicine |
|---|
| Keywords | Pulmonary artery catheter, Frequency caracteristics, Natural frequency, Damping coeffiient, Air bubble |
|---|