UMIN-CTR 臨床試験登録情報の閲覧

術中麻薬投与はシミュレーションを参考にする。しかし手術の種類がシミュレーションと実際の血漿の濃度との差に与える影響は明らかではない。本論文では、異なるタイプの手術、出血の多い長めの手術（腹腔鏡下の前立腺全摘P群）と出血の少ない短めの手術（乳腺手術M群）でシミュレーションと血漿濃度の関係を比較検討した。輸液量は8ml/hとし出血に対しては約1、2倍のヒドロキシエチルでんぷんを投与した。採血は30分おきとした。50人から358サンプルを採血した。フェンタニル血漿濃度はシミュレーションと比例関係を見せたが36％のサンプルが±0.5ng/ml以上の差を認めた。M群では0.3ng/mlの固定バイアスが術中を通じであるが、P群では手術が進むにつれ固定バイアスが+0.3から-0.3ng/mlに減少する傾向を示した。これはP群では出血が増え体外へのロスや希釈の影響が示唆された。手術の種類でシミュレーションと実際の血漿濃度との差に変化が有り麻酔管理には注意が必要である。

Abstract
Background The accuracy of simulation predicted fentanyl concentration in different types of surgical procedure is not fully understood. We wished to estimate the effect of different types of surgical procedure on the accuracy of such simulations.
Findings Fifty patients who had undergone elective mastectomy or laparoscopic prostatectomy, American Society of Anesthesiologists physical status 1, 2, were enrolled. Anesthesia was maintained throughout surgery with sevoflurane and a bolus infusion of fentanyl. A maintenance infusion was administered with 8 mL kg h Ringer acetate solution from the start of anesthesia to completion of blood sampling. An infusion to compensate for blood loss was administered, one to two volumes of hydroxyethyl starch. A blood sample was drawn every 30 min during anesthesia. We measured the plasma concentration of fentanyl in 358 samples from 50 patients. The plasma concentration of fentanyl was correlated significantly with the simulated predicted fentanyl concentration, r 0.734, P 0.01, but 36.0 percent of all samples had a difference greater than 0.5 ng ml. Approximately 0.3 ng mL of a fixed bias was shown throughout mastectomy. During laparoscopic prostatectomy, the fixed bias gradually became negative from 0.3 to minus 0.3 ng mL as the sampling stage proceeded.
Conclusions The predicted concentration of fentanyl was significantly correlated with the plasma concentration of fentanyl, r 0.734. However, there were different patterns of a fixed bias between mastectomy and laparoscopic prostatectomy groups. We should pay attention to this tendency among different surgical procedures.