Linassi Federico, Troyas Carla, Kreuzer Matthias, Spanò Leonardo, Burelli Paolo, Schneider Gerhard, Zanatta Paolo, Carron Michele
From the Department of Pharmaceutical and Pharmacological Sciences, Università degli Studi di Padova, Padova, Italy.
Department of Anesthesiology and Critical Care, Treviso Regional Hospital, AULSS 2 Marca Trevigiana Piazzale Ospedale, Treviso, Italy.
Anesth Analg. 2024 Nov 1;140(6):1276-85. doi: 10.1213/ANE.0000000000007255.
Ketamine administration during stable propofol anesthesia is known to be associated with an increase in bispectral index (BIS) but a "deepening" in the level of hypnosis. This study aimed to evaluate the association between the effect-site concentration of ketamine (CeK) and 2 electroencephalogram (EEG)-derived parameters, the BIS and spectral edge frequency (SEF95), after the administration of a ketamine bolus. Secondary aims included investigating the BIS and SEF95 variations with time and changes in the surgical pleth index (SPI).
We conducted an observational, prospective, single-center study analyzing intraoperative data from 14 adult female patients undergoing breast oncologic surgery. During stable propofol-remifentanil target-controlled infusion (TCI) anesthesia, a ketamine analgesic bolus was delivered with the target CeK set to 1 μg.mL-1 (Domino model) corresponding to a dose of 0.57 mg.kg-1 (interquartile range [IQR] 0.56-0.57 mg.kg-1). Once the CeK reached a value of 1 μg.mL-1, the target CeK was set to 0 μg.mL-1. We determined the median BIS, SEF95, and SPI trends with time and as a function of the modeled CeK.
BIS and SEF95 showed no significant change from when ketamine was administered to when CeK=1 μg.mL-1, but a significant increase was observed at lower CeKs. The maximum BIS was reached at 16.0 minutes [10.2-22.7 minutes] after CeK=1 μg.mL-1, at CeK=0.22 μg.mL-1 [0.12-0.41 μg.mL-1]. The peak SEF95 value was observed at 10.0 minutes [8.62-14.1 minutes] after CeK=1 μg.mL-1, at CeK=0.43 μg.mL-1 [0.25-0.50 μg.mL-1]. No significant association was found between CeK and the registered SPI values.
Our results show that BIS and SEF95, but not SPI, follow a CeK-dependent trend after administering a ketamine bolus. Interestingly, their peak values were not reached at CeK=1 μg.mL-1, but after several minutes after the drug infusion at CeKs in the 0.2 to 0.5 μg.mL-1 range. This may be explained by the specific pharmacodynamics of ketamine and its varying effects at different concentrations, as well as by the time delay associated with the calculation of the BIS.
已知在稳定的丙泊酚麻醉期间给予氯胺酮与脑电双频指数（BIS）升高但催眠深度“加深”有关。本研究旨在评估给予氯胺酮推注后氯胺酮效应室浓度（CeK）与两个脑电图（EEG）衍生参数BIS和频谱边缘频率（SEF95）之间的关联。次要目的包括研究BIS和SEF95随时间的变化以及手术容积指数（SPI）的变化。
我们进行了一项观察性、前瞻性、单中心研究，分析了14例接受乳腺肿瘤手术的成年女性患者的术中数据。在稳定的丙泊酚-瑞芬太尼靶控输注（TCI）麻醉期间，给予氯胺酮镇痛推注，将目标CeK设定为1μg/mL（多米诺模型），对应剂量为0.57mg/kg（四分位间距[IQR]0.56 - 0.57mg/kg）。一旦CeK达到1μg/mL，将目标CeK设定为0μg/mL。我们确定了BIS、SEF95和SPI随时间以及作为模拟CeK函数的中位数趋势。
从给予氯胺酮到CeK = 1μg/mL时，BIS和SEF95无显著变化，但在较低的CeK水平时观察到显著升高。CeK = 1μg/mL后16.0分钟[10.2 - 22.7分钟]，在CeK = 0.22μg/mL[0.12 - 0.41μg/mL]时达到最大BIS。CeK = 1μg/mL后10.0分钟[8.62 - 14.1分钟]，在CeK = 0.43μg/mL[0.25 - 0.50μg/mL]时观察到SEF95峰值。在CeK与记录的SPI值之间未发现显著关联。
我们的结果表明，给予氯胺酮推注后，BIS和SEF95而非SPI遵循CeK依赖性趋势。有趣的是，它们的峰值不是在CeK = 1μg/mL时达到，而是在药物输注后几分钟，CeK在0.2至0.5μg/mL范围内时达到。这可能由氯胺酮的特定药效学及其在不同浓度下的不同作用，以及与BIS计算相关的时间延迟来解释。
