Influence of intensive care treatment on the protein binding of sufentanil and hydromorphone during pain therapy in postoperative cardiac surgery patients

Background: Our objective was to evaluate the effect of intensive care treatment on the protein binding of sufentanil and hydromorphone in cardiac surgery patients during postoperative analgesia using a target-controlled infusion (TCI) and patient-controlled analgesia (PCA). Methods: Fifty adult patients were enrolled in this prospective randomized study; of which, 49 completed the study (age range 40–81 yr). Sufentanil was administered as an analgesic intraoperatively, and hydromorphone was dosed after operation with TCI and PCA until 8 a.m. on the first postoperative day. Arterial plasma samples were collected for drug and protein concentration measurements up to 24 h after cardiac surgery. Corresponding patient data were collected from the electronic patient data system. After explorative data analysis with principal component analysis, multivariate regression analysis and non-linear mixed effects modelling was used to study the effect of treatment on protein binding. Results: Data of 35 patients were analysed. The median protein binding of sufentanil and hydromorphone was 88.4% (IQ range 85.7–90.5%) and 11.6% (IQ range 9.5–14.3%), respectively. Free fraction of sufentanil increased towards the end of the study period, whereas hydromorphone free fraction remained nearly constant. The total sufentanil concentration and volume balance were identified as significant covariates for the protein binding of sufentanil. For the protein binding of hydromorphone, no significant covariate effects were found. Conclusions: Sufentanil protein binding was significantly dependent on changes in the total drug concentration and volume balance addressing the importance of adequate dosing and fluid-guided therapy. Hydromorphone protein binding was nearly constant throughout the study period. Clinical trial registration: EudraCT 2011-003648-31 and ClinicalTrials.gov: NCT01490268

The discriminant power of simultaneous monitoring of spontaneous electroencephalogram and evoked potentials as a predictor of different clinical states of general anesthesia.

Spontaneous or evoked electrical brain activity is increasingly used to monitor general anesthesia. Previous studies investigated the variables from spontaneous electroencephalogram (EEG), acoustic (AEP), or somatosensory evoked potentials (SSEP). But, by monitoring them separately, the available information from simultaneous gathering could be missed. We investigated whether the combination of simultaneous information from EEG, AEP, and SSEP shows a more discriminant power to differentiate between anesthesia states than from information derived from each measurement alone. Therefore, we assessed changes of 30 EEG, 21 SSEP, and 29 AEP variables recorded from 59 patients during four clinical states of general anesthesia: "awake," "light anesthesia," "surgical anesthesia," and "deep surgical anesthesia." The single and combined discriminant powers of EEG, AEP, and SSEP variables as predictors of these states were investigated by discriminant analysis. EEG variables showed a higher discriminant power than AEP or SSEP variables: 85%, 46%, and 32% correctly classified cases, respectively. The frequency of correctly classified cases increased to 90% and 91% with information from EEG + AEP and EEG + AEP + SSEP, respectively. Thus, future anesthesia monitoring should consider combined information simultaneously distributed on different electrophysiological measurements, rather than single variables or their combination from EEG or AEP or SSEP

Influence of intensive care treatment on the protein binding of sufentanil and hydromorphone during pain therapy in postoperative cardiac surgery patients

Background: Our objective was to evaluate the effect of intensive care treatment on the protein binding of sufentanil and hydromorphone in cardiac surgery patients during postoperative analgesia using a target-controlled infusion (TCI) and patient-controlled analgesia (PCA). Methods: Fifty adult patients were enrolled in this prospective randomized study; of which, 49 completed the study (age range 40–81 yr). Sufentanil was administered as an analgesic intraoperatively, and hydromorphone was dosed after operation with TCI and PCA until 8 a.m. on the first postoperative day. Arterial plasma samples were collected for drug and protein concentration measurements up to 24 h after cardiac surgery. Corresponding patient data were collected from the electronic patient data system. After explorative data analysis with principal component analysis, multivariate regression analysis and non-linear mixed effects modelling was used to study the effect of treatment on protein binding. Results: Data of 35 patients were analysed. The median protein binding of sufentanil and hydromorphone was 88.4% (IQ range 85.7–90.5%) and 11.6% (IQ range 9.5–14.3%), respectively. Free fraction of sufentanil increased towards the end of the study period, whereas hydromorphone free fraction remained nearly constant. The total sufentanil concentration and volume balance were identified as significant covariates for the protein binding of sufentanil. For the protein binding of hydromorphone, no significant covariate effects were found. Conclusions: Sufentanil protein binding was significantly dependent on changes in the total drug concentration and volume balance addressing the importance of adequate dosing and fluid-guided therapy. Hydromorphone protein binding was nearly constant throughout the study period. Clinical trial registration: EudraCT 2011-003648-31 and ClinicalTrials.gov: NCT01490268

Identification of Plasma Metabolites Prognostic of Acute Kidney Injury after Cardiac Surgery with Cardiopulmonary Bypass

Acute kidney injury (AKI) is a frequent complication after cardiopulmonary bypass, but early detection of postoperative AKI remains challenging. Protein biomarkers predict AKI excellently in homogeneous cohorts but are less reliable in patients suffering from various comorbidities. We employed nuclear magnetic resonance spectroscopy in a prospective study of 85 adult cardiac surgery patients to identify metabolites prognostic of AKI in plasma specimens collected 24 h after surgery. Postoperative AKI of stages 1–3, as defined by the Acute Kidney Injury Network (AKIN), developed in 33 cases. A random forests classifier trained on the NMR spectra prognosticated AKI across all stages, with an average accuracy of 80 ± 0.9% and an area under the receiver operating characteristic curve of 0.87 ± 0.01. Prognostications were based, on average, on 24 ± 2.8 spectral features. Among the set of discriminative ions and molecules identified were Mg2+, lactate, and the glucuronide conjugate of propofol. Using creatinine, Mg2+, and lactate levels to derive an AKIN index score, we found AKIN 1 disease to be largely indistinguishable from AKIN 0, in concordance with the rather mild nature of AKIN 1 disease