Browsing by Author "Cortinez, Ignacio"

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    Characterization of the temporal profile of the antinociceptive effects of an intravenous bolus of ketamine using the analgesia nociception index in no-anesthetized adult patients
    (2024) Navarrete, Victor; Ibacache, Mauricio; Contreras, Victor; Cortinez, Ignacio
    An effect-site target-controlled infusion (TCI) would allow a more precise titration of intravenous analgesics effect. The analgesia nociception index (ANI) continuously monitors the analgesia/nociception balance during general anesthesia. This study aims to derive a PKPD model of ketamine antinociceptive effect using the Domino PK parameter set and the ANI response data in awake patients without other drugs affecting the ANI response. Twenty awake adult patients were prospectively studied before general anesthesia. Patients received a single intravenous bolus of ketamine 0.1 mgkg- 1, and the subsequent ANI values were recorded. An effect compartment model incorporating the Domino PK parameter set was used to characterize the time lag between ketamine plasma concentrations and the ANI response. The model was parameterized with a single parameter Ke0. An Emax pharmacodynamic model was used to fit the ANI response data. Model parameters were estimated with NONMEM (R) 7.5. The minimum objective function value guided the model construction. After the ketamine administration, basal ANI values increased from 38.5 +/- 4.95 to a maximum of 53.5 +/- 4.95 with an observed time-to-peak effect of 1.83 +/- 0.74 min. Modeling analysis revealed hysteresis between predicted plasma concentrations from the Domino model and observed ANI data. Hysteresis was characterized, incorporating an estimated Keo of 0.238 (CI95% 0.20-0.28) min-1 to the described PK parameters set. The developed PKPD model, using Domino's PK parameters and the ANI response data, adequately characterized the temporal profile of ketamine's antinociceptive effect. The current estimated model parameters can be used to perform an effect-site TCI of ketamine for analgesic purposes.
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    Clinical Presentation and Perioperative Management of Pheochromocytomas and Paragangliomas: A 4-Decade Experience
    (ENDOCRINE SOC, 2021) Uslar, Thomas; San Francisco, Ignacio F.; Olmos, Roberto; Macchiavelo, Stefano; Zuniga, Alvaro; Rojas, Pablo; Garrido, Marcelo; Huete, Alvaro; Mendez, Gonzalo P.; Cortinez, Ignacio; Zemelman, Jose Tomas; Cifuentes, Joaquin; Castro, Fernando; Olivari, Daniela; Dominguez, Jose Miguel; Arteaga, Eugenio; Fardella, Carlos E.; Valdes, Gloria; Tagle, Rodrigo; Baudrand, Rene
    Purpose: Latin American reports on pheochromocytomas and paragangliomas (PPGLs) are scarce. Recent studies demonstrate changes in clinical presentation and management of these patients. Herein, we assessed the main characteristics of PPGL patients in our academic center over the past 4 decades.
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    Cognitive function mediates the relationship between age and anaesthesia-induced oscillatory-specific alpha power
    (2023) Boncompte, Gonzalo; Freedman, Isaac; Qu, Jason; Turco, Isabella; Khawaja, Zain Q.; Cortinez, Ignacio; Pedemonte, Juan C.; Akeju, Oluwaseun
    Cognitive decline is common among older individuals, and although the underlying brain mechanisms are not entirely understood, researchers have suggested using EEG frontal alpha activity during general anaesthesia as a potential biomarker for cognitive decline. This is because frontal alpha activity associated with GABAergic general anaesthetics has been linked to cognitive function. However, oscillatory-specific alpha power has also been linked with chronological age. We hypothesize that cognitive function mediates the association between chronological age and (oscillatory-specific) alpha power. We analysed data from 380 participants (aged over 60) with baseline screening assessments and intraoperative EEG. We utilized the telephonic Montreal Cognitive Assessment to assess cognitive function. We computed total band power, oscillatory-specific alpha power, and aperiodics to measure anaesthesia-induced alpha activity. To test our mediation hypotheses, we employed structural equation modelling. Pairwise correlations between age, cognitive function and alpha activity were significant. Cognitive function mediated the association between age and classical alpha power [age -> cognitive function -> classical alpha; beta = -0.0168 (95% confidence interval: -0.0313 to -0.00521); P = 0.0016] as well as the association between age and oscillatory-specific alpha power [age -> cognitive function -> oscillatory-specific alpha power; beta = -0.00711 (95% confidence interval: -0.0154 to -0.000842); P = 0.028]. However, cognitive function did not mediate the association between age and aperiodic activity (1/f slope, P = 0.43; offset, P = 0.0996). This study is expected to provide valuable insights for anaesthesiologists, enabling them to make informed inferences about a patient's age and cognitive function from an analysis of anaesthetic-induced EEG signals in the operating room. To ensure generalizability, further studies across different populations are needed.