What We Already Know about This Topic: The nociception level index (Medasense Biometrics Ltd., Ramat Gan, Israel), is a reliable measure of moderate to intense noxious stimulation during anesthesia... Show moreWhat We Already Know about This Topic: The nociception level index (Medasense Biometrics Ltd., Ramat Gan, Israel), is a reliable measure of moderate to intense noxious stimulation during anesthesia and surgery What This Article Tells Us That Is New: In a randomized trial in patients having major abdominal surgery, compared to standard practice, nociception level-guided analgesia resulted in 30% less intraoperative remifentanil consumption Background: The multidimensional index of nociception, the nociception level, outperforms blood pressure and heart rate in detection of nociceptive events during anesthesia. We hypothesized that nociception level–guided analgesia reduces opioid consumption and suboptimal anesthesia events such as low blood pressure and use of vasoactive medication. Methods: In this single-blinded randomized study, 80 American Society of Anesthesiologists class I–III adult patients of either sex, scheduled for major abdominal procedures under remifentanil/propofol anesthesia by target-controlled infusion, were included. During the procedure nociception level, noninvasive blood pressure, and heart rate were monitored. Patients were randomized to receive standard clinical care or nociception level–guided analgesia. In the nociception level–guided group, remifentanil concentration was reduced when index values were less than 10 or increased when values were above 25 for at least 1 min, in steps of 0.5 to 1.0 ng/ml. Propofol was titrated to bispectral index values between 45 and 55. The primary outcomes of the study were remifentanil and propofol consumption and inadequate anesthesia events. Results: Compared with standard care, remifentanil administration was reduced in nociception level–guided patients from (mean ± SD) 0.119 ± 0.033 to 0.086 ± 0.032 μg · kg-1 · min-1 (mean difference, 0.039 μg · kg-1 · min-1; 95% CI, 0.025–0.052 μg · kg-1 · min-1; P < 0.001). Among nociception level–guided patients, 2 of 40 (5%) experienced a hypotensive event (mean arterial pressure values less than 55 mm Hg) versus 11 of 40 (28%) patients in the control group (relative risk, 0.271; 95% CI, 0.08–0.77; P = 0.006). In the nociception level–guided group, 16 of 40 (40%) patients received vasoactive medication versus 25 of 40 (63%) patients in the standard care group (relative risk, 0.64; 95% CI, 0.40–0.99; P = 0.044). Conclusions: Nociception level-guided analgesia during major abdominal surgery resulted in 30% less remifentanil consumption. Show less
It is not straightforward to simultaneously evaluate benefits and harms of pain management, as different drugs may possess different analgesia and adverse effect profiles. Utility functions,... Show moreIt is not straightforward to simultaneously evaluate benefits and harms of pain management, as different drugs may possess different analgesia and adverse effect profiles. Utility functions, derived from the pharmacokinetics and pharmacodynamics of individual outcome parameters, have been constructed to address this problem. Here we construct "pragmatic" utility functions based on measurements of benefit and harms, but without making assumptions about the underlying pharmacokinetics and pharmacodynamics. Using data from two previous studies, utility functions were designed by estimating the probability of occurrence of benefit and harm and combining these into one function. Study 1 was a clinical trial on the effect of oral pregabalin on pain relief in chronic pancreatitis patients, with end-points analgesia and dizziness monitored for 21 days. Study 2 was an experimental study on the effect of intravenous fentanyl on antinociception and respiratory depression in healthy volunteers. From study 1 the utility function was negative the first week of treatment, indicative of the greater probability of dizziness than analgesia, but positive thereafter. From study 2 the utility function showed a nadir 30 minutes after dosing, after which the probability function slowly increased towards zero. A pragmatic utility function based on the probability of two binary outcomes, analgesia and adverse effect, was successfully constructed using data from two previous studies. Results yielded valuable insights into the utility of treatment and may be highly educative for physicians and may be used in development of potent analgesics with serious side effects Show less
Schrier, R. van der; Jonkman, K.; Velzen, M. van; Olofsen, E.; Drewes, A.M.; Dahan, A.; Niesters, M. 2017
This thesis concerns five studies where the statistical consequences of violations of modeling assumptions are assessed using experimental and simulated pharmacokinetic-pharmacodynamic data. The... Show moreThis thesis concerns five studies where the statistical consequences of violations of modeling assumptions are assessed using experimental and simulated pharmacokinetic-pharmacodynamic data. The first study describes the development of an open source web application for Bland-Altman analysis of comparison data, which is able to take into account both intra- and interindividual variability. In the second study the behavior of Akaike's information theoretic criterion is investigated in the presence of interindividual variability. The effects of neglecting or allowing for process noise are described in the third and fourth studies, for surrogate measures of clinical endpoints such depth of anesthesia and analgesia. In the fifth study pharmacodynamic model parameter estimates are compared when these are based on venous versus arterial blood samples. Show less
Dahan, A.; Boom, M.; Sarton, E.; Hay, J.; Groeneveld, G.J.; Neukirchen, M.; ... ; Olofsen, E. 2017
