Electrical resistance and current leakage of appliances for transurethral resection

Abstract

経尿道的前立腺切除術に用いていた7本の古い双極性のループ, 3本の新品双極性ループ((1), (2), (3)), 経尿道的膀胱腫瘍切除術に用いた2本の新品双極性ループ((4), (5)), および経尿道的前立腺切除術に用いた新品の単極性ループ((6), (7), (8), (9))の電気抵抗および漏電について検査した.7本の古い双極性ループのうち2本に漏電がみられ, 5本は漏電がなかった.漏電のみられた2本の電気抵抗は, 4.4および17オーム(Ω)であった.つぎに新品の双極性ループ5本((1)から(5))の, 使用前の電気抵抗を調べると0.5から0.6Ωであったが, ループ(1)は6回使用後も5Ω以下, ループ(3)は5回使用でも2.8Ωだった.ループ(2)は, 2回使用後に115Ωまで上昇したが, ループ(1), (2)および(3)を用いた平均切除時間は, 66, 64および62分と差がなかった.ループ(4)は3回使用で14Ω, ループ(5)は6回使用でも1Ω以下であったが, これらの5本はいずれも漏電がみられなかった.一方単極性ループの4本((6)から(9))は1回使用後に漏電を示すとともに, かなりの電気抵抗がみられた.これらは双極性ループの適切な交換と, 単極性ループの1回毎の交換が必要なことを示していた

Urethral stricture following transurethral resection of the prostate (TUR-P) is closely related to the electrical resistance and current leakage of appliances. Electrical resistance and leakage were therefore investigated in 7 old bipolar loops, 3 new bipolar loops (1, 2 and 3) used for TUR-P, 2 new bipolar loops (4 and 5) for TUR-bladder tumor (TUR-Bt), and 4 new monopolar loops (6 through 9) for TUR-P. Two of the 7 old bipolar loops were found to be positive and 5 negative for current leakage. The 2 positive loops had resistances of 4.4 and 17 ohm . Before use, the electrical resistance of the 5 new bipolar loops (1 to 5) ranged from 0.5 to 0.6 ohm. The resistance of loop 1 was less than 5 ohm after the sixth use, and that of loop 3 was 2.8 ohm after the fifth use. By contrast, loop 2 exhibited resistance of 115 ohm after the third use. The average operation time for loops 1, 2 and 3 were 66, 64 and 62 minutes. Loop 4 showed resistance of 14 ohm after the third use, and loop 5 1 ohm even after the sixth use. Furthermore, none of the 5 loops showed current leakage. On the other hand, all 4 monopolar loops (6 through 9) exhibited current leakage after the first use, and showed relatively high electrical resistance. These findings demonstrate the necessity of timely replacement of bipolar loops and the exchange of monopolar loops after the first use.