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Braathen MR, Rigby-Jones AE, Ræder J, Spigset O, Heier T. Pharmacokinetics of propofol in severely obese surgical patients. Acta Anaesthesiol Scand 2024; 68:726-736. [PMID: 38481015 DOI: 10.1111/aas.14407] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2023] [Revised: 02/23/2024] [Accepted: 02/26/2024] [Indexed: 06/20/2024]
Abstract
BACKGROUND Existing PK models of propofol include sparse data from very obese patients. The aim of this study was to develop a PK model based on standardised surgical conditions and spanning from normal-weight up to, and including, a high number of very obese patients. METHODS Adult patients scheduled for laparoscopic cholecystectomy or bariatric surgery were studied. Anaesthesia was induced with propofol 2 mg/kg adjusted body weight over 2 min followed by 6 mg/kg/h adjusted body weight over 30 min. For the remainder of the operation anaesthesia was maintained with sevoflurane. Remifentanil was dosed according to clinical need. Eight arterial samples were drawn in a randomised block sampling regimen over a span of 24 h. Time-concentration data were analysed by population PK modelling using non-linear mixed-effects modelling. RESULTS Four hundred and seventy four serum propofol concentrations were collected from 69 patients aged 19-60 years with a BMI 21.6-67.3 kg/m2. Twenty one patients had a BMI above 50 kg/m2. A 3-compartment PK model was produced wherein three different body weight descriptors and sex were included as covariates in the final model. Total body weight was found to be a covariate for clearance and Q3; lean body weight for V1, V2 and Q2; predicted normal weight for V3 and sex for V1. The fixed allometric exponent of 0.75 applied to all clearance parameters improved the performance of the model. Accuracy and precision were 1.4% and 21.7% respectively in post-hoc performance evaluation. CONCLUSION We have developed a new PK model of propofol that is suitable for all adult weight classes. Specifically, it is based on data from an unprecedented number of individuals with very high BMI.
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Affiliation(s)
- Martin Rygh Braathen
- Institute of Clinical Medicine, Faculty of Medicine, University of Oslo, Oslo, Norway
- Department of Anesthesiology, Division of Critical Care, Oslo University Hospital, Oslo, Norway
| | | | - Johan Ræder
- Institute of Clinical Medicine, Faculty of Medicine, University of Oslo, Oslo, Norway
- Department of Anesthesiology, Division of Critical Care, Oslo University Hospital, Oslo, Norway
| | - Olav Spigset
- Department of Clinical Pharmacology, St. Olav University Hospital, Trondheim, Norway
- Department of Clinical and Molecular Medicine, Faculty of Medicine and Health Sciences, Norwegian University of Science and Technology, Trondheim, Norway
| | - Tom Heier
- Institute of Clinical Medicine, Faculty of Medicine, University of Oslo, Oslo, Norway
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Ziqiang F, Keyu H, Yun X, Li L, Yiping B. Effect of esketamine on the EC50 of remifentanil for blunting cardiovascular responses to endotracheal intubation in female patients under general anesthesia: a sequential allocation dose-finding study. BMC Anesthesiol 2024; 24:67. [PMID: 38383307 PMCID: PMC10880282 DOI: 10.1186/s12871-024-02454-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2023] [Accepted: 02/11/2024] [Indexed: 02/23/2024] Open
Abstract
BACKGROUND This study aimed to investigate the effect of esketamine on the dose-effect relationship between remifentanil and the cardiovascular response to endotracheal intubation during target-controlled infusion (TCI) of propofol. METHODS Patients underwent elective gynecological laparoscopic surgery under general anesthesia with endotracheal intubation, aged 18-65 years, American Society of Anesthesiologists class I or II, 18 kg/m2 ≤ body mass index ≤ 30 kg/m2, were randomly divided into the control (group C) and esketamine groups (group E). Before anesthesia induction, group E received an intravenous injection of 0.3 mg/kg of esketamine, while group C received an equal dose of physiological saline. TCI of propofol to the effect-site concentration (EC) of 3.0 μg/mL, and then TCI of remifentanil to the effect room and intravenous injection of rocuronium 0.6 mg/kg after MOAA/S was 0. Endotracheal intubation was performed after 2 min. Dixon's modified sequential method was used, and the initial EC of remifentanil was 3.0 ng/mL. The EC of remifentanil was determined according to the intubation response of the previous patient, with an adjacent concentration gradient of 0.3 ng/mL. The EC50 and EC95 values and their 95% confidence intervals (CIs) were determined using probit regression analysis. RESULTS The EC50 for cardiovascular response inhibition to endotracheal intubation using remifentanil was 3.91 ng/mL (95% CI: 3.59-4.33 ng/mL) and EC95 was 4.66 ng/mL (95% CI: 4.27-6.23 ng/mL) with TCI of propofol 3.0 μg/mL. After intravenous administration of 0.3 mg/kg of esketamine, the EC50 of remifentanil was 3.56 ng/mL (95% CI: 3.22-3.99 ng/mL) and EC95 was 4.31 ng/mL (95% CI: 3.91-5.88 ng/mL). CONCLUSIONS Combined with TCI of propofol 3.0 μg/mL for anesthesia induction, esketamine significantly reduced the EC50 and EC95 of remifentanil to inhibit the cardiovascular response to endotracheal intubation. TRIAL REGISTRATION The trial was registered in the Chinese Clinical Trials Registry ( www.chictr.org.cn ; registration number: ChiCTR2200064932; date of registration:24/10/2022).
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Affiliation(s)
- Fan Ziqiang
- Southwest Medical University, Luzhou, 646000, Sichuan Province, China
- Chongqing University Fuling Hospital, Fuling, Chongqing, 408000, China
| | - He Keyu
- Chongqing University Fuling Hospital, Fuling, Chongqing, 408000, China
| | - Xue Yun
- Chongqing University Fuling Hospital, Fuling, Chongqing, 408000, China
| | - Liu Li
- Southwest Medical University, Luzhou, 646000, Sichuan Province, China
- Anesthesiology and Critical Care Medicine Key Laboratory of Luzhou, Southwest Medical University, Luzhou, 646000, Sichuan Province, China
| | - Bai Yiping
- Southwest Medical University, Luzhou, 646000, Sichuan Province, China.
- Anesthesiology and Critical Care Medicine Key Laboratory of Luzhou, Southwest Medical University, Luzhou, 646000, Sichuan Province, China.
- Department of Anesthesiology, The Affiliated Hospital of Southwest Medical University, Luzhou, China, Sichuan Province, 646000.
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Doo AR, Ki MJ, Park SO, Lee JH, Ko S. Influence of body fatness on propofol requirements for loss of consciousness in target-controlled infusion: A STROBE-compliant study. Medicine (Baltimore) 2022; 101:e30179. [PMID: 36107531 PMCID: PMC9439823 DOI: 10.1097/md.0000000000030179] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
This prospective observational study evaluated the effects of body fat on the pharmacologic effect of propofol. Hundred patients aged 18 to 75 years who were scheduled to undergo orthopedic surgery under regional block were enrolled. All participants underwent bioelectrical impedance analysis and were allocated into 2 groups: the high and normal adiposity group, according to percent body fat. Following successful regional block, propofol was incrementally infused until loss of consciousness (LOC) with a target-controlled infusion pump. The effect-site concentration of propofol at LOC and the total infused dose of propofol per total body weight until LOC were recorded. At the end of the surgery, the infusion of propofol was stopped. The elapsed time to recovery of consciousness (ROC) and the effect-site concentration at ROC were recorded. These pharmacologic data were compared between 2 groups. The effect-site concentration of propofol at LOC (µg/mL) was significantly lower in the high adiposity group than in the normal group in both sexes (3.5 ± 0.4 vs 3.9 ± 0.6; P = .020 in males, and 3.4 [interquartile range: 2.9-3.5] vs 3.8 [interquartile range: 3.3-3.9]; P = .006 in females). Total dose per total body weight until LOC (mg/kg) were also significantly lower in the high adiposity group than in the normal group. There was no significant difference in the data related to ROC. The pharmacologic effects of propofol may be affected by the composition of body components. The concentration of propofol using a target-controlled infusion system may be diminished in patients with a high proportion of body fat.
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Affiliation(s)
- A. Ram Doo
- Department of Anesthesiology and Pain Medicine, Jeonbuk National University Medical School, Jeonju, South Korea
- Research Institute of Clinical Medicine of Jeonbuk National University-Biomedical Research Institute of Jeonbuk National University Hospital, Jeonju, South Korea
| | - Min Jong Ki
- Department of Anesthesiology and Pain Medicine, Jeonbuk National University Medical School, Jeonju, South Korea
- Research Institute of Clinical Medicine of Jeonbuk National University-Biomedical Research Institute of Jeonbuk National University Hospital, Jeonju, South Korea
| | - Seong Ok Park
- Department of Anesthesiology and Pain Medicine, Jeonbuk National University Medical School, Jeonju, South Korea
- Research Institute of Clinical Medicine of Jeonbuk National University-Biomedical Research Institute of Jeonbuk National University Hospital, Jeonju, South Korea
| | - Jun Ho Lee
- Department of Anesthesiology and Pain Medicine, Jeonbuk National University Medical School, Jeonju, South Korea
- Research Institute of Clinical Medicine of Jeonbuk National University-Biomedical Research Institute of Jeonbuk National University Hospital, Jeonju, South Korea
| | - Seonghoon Ko
- Department of Anesthesiology and Pain Medicine, Jeonbuk National University Medical School, Jeonju, South Korea
- Research Institute of Clinical Medicine of Jeonbuk National University-Biomedical Research Institute of Jeonbuk National University Hospital, Jeonju, South Korea
- *Corresponence: Seonghoon Ko, Department of Anesthesiology and Pain Medicine, Medical School, Jeonbuk National University, 20 Geonji-ro, Deokjin-gu, Jeonju, Jeollabuk-do 54907, South Korea (e-mail: )
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Wu Z, Gong J, He X, Wu Z, Shen J, Shang J. Body mass index and pharmacodynamics of target-controlled infusion of propofol: A prospective non-randomized controlled study. J Clin Pharm Ther 2022; 47:662-667. [PMID: 35018648 DOI: 10.1111/jcpt.13594] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2021] [Accepted: 12/14/2021] [Indexed: 11/26/2022]
Abstract
WHAT IS KNOWN AND OBJECTIVE In our preliminary study, there were large individual variations at sedation levels during propofol target-controlled infusion (TCI). The present study aimed to assess the effects of body mass index (BMI) on the pharmacodynamic index of propofol TCI. METHODS This prospective, non-randomized controlled trial evaluated 175 female patients undergoing breast lumpectomy. Anesthesia was induced with propofol using the TCI system embedded Schnider model. The effect compartment concentration was set to 3 μg/ml, and the start time of infusion was recorded. When the target concentration reached 3 μg/ml, the patient could not be awakened (Ramsay sedation score ≥4), and when the Bispectral Index (BIS) was <60, the infusion was discontinued, and the time point was recorded. The observation end-point was set at the Observer's Assessment of Alertness/Sedation (OAA/S) score of <4. The correlation between the BMI and the pharmacodynamic index of propofol was evaluated. RESULTS AND DISCUSSION Propofol induction time was significantly correlated with the BMI (p < 0.001). The induction time of the underweight subjects was 10.14 ± 2.19 min, which was remarkably higher than that of normal weight (6.48 ± 3.44 min) and overweight (4.75 ± 2.53 min) individuals (p < 0.001). There were still significant differences after multivariable-adjusted regressions (p < 0.001). There were no significant differences in recovery time and sedative effect indicators, such as Ramsay score, BIS value, and effect compartment concentration, between the three groups (p > 0.05 for all). WHAT IS NEW AND CONCLUSION These results suggest that the BMI is one of the critical factors affecting the pharmacodynamic index of propofol TCI, and the induction time decreased progressively with increasing BMI. The Schnider model might underpredict doses of propofol for underweight individuals.
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Affiliation(s)
- Zijuan Wu
- Department of Pharmacy, The Affiliated Changzhou No. 2 People's Hospital of Nanjing Medical University, Changzhou, China
| | - Jinhong Gong
- Department of Pharmacy, The Affiliated Changzhou No. 2 People's Hospital of Nanjing Medical University, Changzhou, China
| | - Xiaomei He
- Department of Pharmacy, The Affiliated Changzhou No. 2 People's Hospital of Nanjing Medical University, Changzhou, China
| | - Zhouquan Wu
- Department of Anesthesiology, The Affiliated Changzhou No. 2 People's Hospital of Nanjing Medical University, Changzhou, China
| | - Jingjing Shen
- Department of Anesthesiology, The Affiliated Changzhou No. 2 People's Hospital of Nanjing Medical University, Changzhou, China
| | - Jingjing Shang
- Department of Pharmacy, The Affiliated Changzhou No. 2 People's Hospital of Nanjing Medical University, Changzhou, China
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Sarraf E. Bolus pharmacokinetics: moving beyond mass-based dosing to guide drug administration. J Pharmacokinet Pharmacodyn 2020; 47:573-581. [PMID: 32812097 DOI: 10.1007/s10928-020-09709-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2020] [Accepted: 08/10/2020] [Indexed: 11/30/2022]
Abstract
Despite the common approach of bolus drug dosing using a patient's mass, a more tailored approach would be to use empirically derived pharmacokinetic models. Previously, this could only be possible though the use of computer simulation using programs which are rarely available in clinical practice. Through mathematical manipulations and approximations, a simplified set of equations is demonstrated that can identify a bolus dose required to achieve a specified target effect site concentration. The proposed solution is compared against simulations of a wide variety of pharmacokinetic models. This set of equations provides a near-identical solution to the simulation approach. A boundary condition is established to ensure the derived equations have an acceptable error. This approach may allow for more precise administration of medications with the use of point of care technology and potentially allows for pharmacokinetic dosing in artificial intelligence problems.
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Affiliation(s)
- Elie Sarraf
- Department of Anesthesiology & Perioperative Medicine, Penn State Health Milton S. Hershey Medical Center, 500 University Drive, H187, Hershey, PA, 17033, USA.
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Park J, Choi S, Park J, Lee K, Yun H, Lee E, Choi B, Noh G. Population pharmacokinetic analysis of propofol in underweight patients under general anaesthesia. Br J Anaesth 2018; 121:559-566. [DOI: 10.1016/j.bja.2018.04.045] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2017] [Revised: 03/14/2018] [Accepted: 05/20/2018] [Indexed: 11/16/2022] Open
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Advances in pharmacokinetic modeling: target controlled infusions in the obese. Curr Opin Anaesthesiol 2018; 31:415-422. [PMID: 29794852 DOI: 10.1097/aco.0000000000000619] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
PURPOSE OF REVIEW The use of conventional pharmacokinetic parameters sets 'models' derived from nonobese patients has proven inadequate to administer intravenous anesthetics in the obese population and is commonly associated with higher than anticipated plasma propofol concentrations when used with target (plasma or effect site) controlled infusion pumps. In this review we will describe recent modeling strategies to characterize the disposition of intravenous anesthetics in the obese patient and will show clinically relevant aspects of new model's performance in the obese population. RECENT FINDINGS Because clearance of a drug increases in a nonlinear manner with weight, nonlinear relationships better scale infusion rates between lean and obese individuals. Allometric concepts have been successfully used to describe size-related nonlinear changes in clearances. Other nonlinear scaling options include the use of descriptors such as body surface area, lean body weight, fat-free mass, and normal fat mass. Newer pharmacokinetic models, determined from obese patient data, have been developed for propofol and remifentanil using allometric concepts and comprehensive size descriptors. SUMMARY Pharmacokinetic models to perform target-controlled infusion in the obese population should incorporate descriptors that reflect with greater precision the influence of body composition in volumes and clearances of each drug. It is our hope that commercially available pumps will soon incorporate these new models to improve the performance of this technique in the obese population.
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Cortínez LI, Sepúlveda P, Rolle A, Cottin P, Guerrini A, Anderson BJ. Effect-Site Target-Controlled Infusion in the Obese: Model Derivation and Performance Assessment. Anesth Analg 2018; 127:865-872. [PMID: 29401079 DOI: 10.1213/ane.0000000000002814] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
BACKGROUND The aim of this study is to derive a propofol pharmacokinetic (PK) pharmacodynamic (PD) model to perform effect-site target-controlled infusion (TCI) in obese patients, and to analyze its performance along with that of other available PK models. METHODS In the first step of the study, a 3-compartment PK model linked to a sigmoidal inhibitory Emax PD model by a first-order rate constant (keo) was used to fit propofol concentration-bispectral index (BIS) data. Population modeling analysis was performed by nonlinear mixed effects regression in NONMEM (ICON, Dublin, Ireland). PK data from 3 previous studies in obese adult patients (n = 47), including PD (BIS) data from 1 of these studies (n = 20), were pooled and simultaneously analyzed. A decrease in NONMEM objective function (ΔOBJ) of 3.84 points, for an added parameter, was considered significant at the 0.05 level. In the second step of the study, we analyzed the predictive performance (median predictive errors [MDPE] and median absolute predictive errors [MDAPE]) of the current model and of other available models using an independent data set (n = 14). RESULTS Step 1: The selected PKPD model produced an adequate fit of the data. Total body weight resulted in the best size scalar for volumes and clearances (ΔOBJ, -18.173). Empirical allometric total body weight relationships did not improve model fit (ΔOBJ, 0.309). A lag time parameter for BIS response improved the fit (ΔOBJ, 89.593). No effect of age or gender was observed. Step 2: Current model MDPE and MDAPE were 11.5% (3.7-25.0) and 26.8% (20.7-32.6) in the PK part and 0.4% (-10.39 to 3.85) and 11.9% (20.7-32.6) in the PD part. The PK model developed by Eleveld et al resulted in the lowest PK predictive errors (MDPE = <10% and MDAPE = <25%). CONCLUSIONS We derived and validated a propofol PKPD model to perform effect-site TCI in obese patients. This model, derived exclusively from obese patient's data, is not recommended for TCI in lean patients because it carries the risk of underdosing.
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Affiliation(s)
- Luis I Cortínez
- From the Department of Anaesthesiology, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Pablo Sepúlveda
- Servicio de Anestesia, Clínica Alemana Universidad del Desarrollo, Santiago, Chile
| | - Augusto Rolle
- From the Department of Anaesthesiology, Pontificia Universidad Católica de Chile, Santiago, Chile
| | | | | | - Brian J Anderson
- Department of Anaesthesiology, University of Auckland, Auckland, New Zealand
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Abstract
Abstract
Background
The influence of obesity on the pharmacokinetic (PK) behavior of remifentanil is incompletely understood. The aim of the current investigation was to develop a new population PK model for remifentanil that would adequately characterize the influence of body weight (among other covariates, e.g., age) on the disposition of remifentanil in the general adult population. We hypothesized that age and various indices of body mass would be important covariates in the new model.
Methods
Nine previously published data sets containing 4,455 blood concentration measurements from 229 subjects were merged. A new PK model was built using nonlinear mixed-effects modeling. Satisfactory model performance was assessed graphically and numerically; an internal, boot-strapping validation procedure was performed to determine the CIs of the model.
Results
Body weight, fat-free body mass, and age (but not body mass index) exhibited significant covariate effects on certain three-compartment model parameters. Visual and numerical assessments of model performance were satisfactory. The bootstrap procedure showed satisfactory CIs on all of the model parameters.
Conclusions
A new model estimated from a large, diverse data set provides the PK foundation for remifentanil dosing calculations in adult obese and elderly patients. It is suitable for use in target-controlled infusion systems and pharmacologic simulation.
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Frederico Avendaño C, Cortínez LI, Ramírez-Paesano CR. Comparison of the Cortínez and the Schnider models with a targeted effect-site TCI of 3 mcg/ml in biophase in healthy volunteers. REVISTA ESPANOLA DE ANESTESIOLOGIA Y REANIMACION 2016; 63:556-563. [PMID: 27117625 DOI: 10.1016/j.redar.2016.03.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2015] [Revised: 03/03/2016] [Accepted: 03/12/2016] [Indexed: 06/05/2023]
Abstract
OBJECTIVE To compare the Cortínez and Schnider models in effect-site TCI mode (3 mcg/ml) in healthy volunteers. METHODS Ten healthy volunteers were prospectively studied on 2 occasions. Propofol was administered with the Cortínez or the Schnider models, as randomly assigned. Times and predicted concentrations at the time of loss and recovery of consciousness (LOC and ROC), mass of drug administered, BIS, and haemodynamic variables were compared. Statistical analysis was with paired Wilcoxon test. A P<.05 was considered significant. RESULTS The propofol bolo was higher (1.4 [1.3-1.6] versus 0.9 [0.7-1.3] mg/kg, P=.005) and the LOC occurred earlier (1.33 [0.67-6.83] versus 3.87 [1.66-11.08] minutes, P=.02) with the Cortínez model compared to the Schnider model. With the Cortínez model, LOC occurred at an effect site concentrations of 2.6 (1.65-3.0) mcg/ml. With the Schnider model, LOC occurred at 3.87 min (1.66-11.8) after reaching the target of 3 mcg/ml. (P=.001). BIS values, infusion rates, and haemodynamic variables were similar between models after 20minutes of infusion (P>.5). Recovery (ROC) was longer with the Cortínez model (11.6 [8.1-16.2] vs. 8.5 [4.7-15.5] min, P=.003). CONCLUSIONS The Cortínez model is a good alternative to the Schnider model for use in effect-site TCI mode in normal weight subjects. With the target used in this study (3 mcg/ml), the slower Ke0 incorporated into the Cortínez model better discriminated the LOC time.
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Affiliation(s)
| | - L I Cortínez
- Departamento de Anestesiología, Escuela de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile
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Obara S, Morimoto I, Iseki Y, Oishi R, Mogami M, Imaizumi T, Hosono A, Hakozaki T, Nakano Y, Isosu T, Murakawa M. THE EFFECT OF OBESITY ON DOSE OF DEXMEDETOMIDINE WHEN ADMINISTERED WITH FENTANYL DURING POSTOPERATIVE MECHANICAL VENTILATION--RETROSPECTIVE. Fukushima J Med Sci 2015; 61:38-46. [PMID: 25946907 DOI: 10.5387/fms.2014-19] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
We carried out a retrospective investigation on the effect of obesity on dexmedetomidine (DEX) requirements when administered with fentanyl (FEN) during mechanical ventilation after major surgeries. After Institutional Review Board approval, 14 obese patients with a body mass index (BMI) ≥ 30 kg/m(2) and the same number of non-obese patients with similar backgrounds to the obese patients were selected from medical records. Doses of DEX in the first 48 h or until the end of sedation or extubation were calculated for comparison. In addition to comparison of dosing between the groups, associations between total body weight (TBW), BMI, and lean body mass (LBM) values and doses of DEX (mcg/h), between BMI and various indices (i.e., amount per TBW per hour and amount per LBM per hour) of DEX doses, and between above indices of DEX and FEN doses were also examined. There were no significant differences in DEX dose indices between the groups. However, DEX requirements (mcg/h) were significantly increased with TBW (kg) (r = 0.51, P = 0.003), BMI (r = 0.49, P = 0.006) and LBM (kg) (r = 0.42, P = 0.02), which might have enhanced the DEX metabolism with physiological changes with obesity. These findings will be beneficial for future clinical pharmacological analysis of DEX.
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Affiliation(s)
- Shinju Obara
- Associate Professor, Surgical Operation Department, Fukushima Medical University Hospital
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Cortínez LI, De la Fuente N, Eleveld DJ, Oliveros A, Crovari F, Sepulveda P, Ibacache M, Solari S. Performance of propofol target-controlled infusion models in the obese: pharmacokinetic and pharmacodynamic analysis. Anesth Analg 2014; 119:302-310. [PMID: 24977639 DOI: 10.1213/ane.0000000000000317] [Citation(s) in RCA: 65] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
BACKGROUND Obesity is associated with important physiologic changes that can potentially affect the pharmacokinetic (PK) and pharmacodynamic (PD) profile of anesthetic drugs. We designed this study to assess the predictive performance of 5 currently available propofol PK models in morbidly obese patients and to characterize the Bispectral Index (BIS) response in this population. METHODS Twenty obese patients (body mass index >35 kg/m), aged 20 to 60 years, scheduled for laparoscopic bariatric surgery, were studied. Anesthesia was administered using propofol by target-controlled infusion and remifentanil by manually controlled infusion. BIS data and propofol infusion schemes were recorded. Arterial blood samples to measure propofol were collected during induction, maintenance, and the first 2 postoperative hours. Median performance errors (MDPEs) and median absolute performance errors (MDAPEs) were calculated to measure model performance. A PKPD model was developed using NONMEM to characterize the propofol concentration-BIS dynamic relationship in the presence of remifentanil. RESULTS We studied 20 obese adults (mean weight: 106 kg, range: 85-141 kg; mean age: 33.7 years, range: 21-53 years; mean body mass index: 41.4 kg/m, range: 35-52 kg/m). We obtained 294 arterial samples and analyzed 1431 measured BIS values. When total body weight (TBW) was used as input of patient weight, the Eleveld allometric model showed the best (P < 0.0001) performance with MDPE = 18.2% and MDAPE = 27.5%. The 5 tested PK models, however, showed a tendency to underestimate propofol concentrations. The use of an adjusted body weight with the Schnider and Marsh models improved the performance of both models achieving the lowest predictive errors (MDPE = <10% and MDAPE = <25%; all P < 0.0001). A 3-compartment PK model linked to a sigmoidal inhibitory Emax PD model by a first-order rate constant (ke0) adequately described the propofol concentration-BIS data. A lag time parameter of 0.44 minutes (SE = 0.04 minutes) to account for the delay in BIS response improved the fit. A simulated effect-site target of 3.2 μg/mL (SE = 0.17 μg/mL) was estimated to obtain BIS of 50, in the presence of remifentanil, for a typical patient in our study. CONCLUSIONS The Eleveld allometric PK model proved to be superior to all other tested models using TBW. All models, however, showed a trend to underestimate propofol concentrations. The use of adjusted body weight instead of TBW with the traditional Schnider and Marsh models markedly improved their performance achieving the lowest predictive errors of all tested models. Our results suggest no relevant effect of obesity on both the time profile of BIS response and the propofol concentration-BIS relationship.
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Affiliation(s)
- Luis I Cortínez
- From the *Departmento de Anestesiología, Escuela de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile; †Department of Anesthesiology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands; ‡Departmento de Cirugía, Escuela de Medicina, Pontificia Universidad Católica de Chile; §Departamento de Anestesiología, Facultad de Medicina, Clínica Alemana-Universidad del Desarrollo; and ‖Departmento de Laboratorio Clínico, Escuela de Medicina, Pontificia, Universidad Católica de Chile, Santiago, Chile
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Eleveld DJ, Proost JH, Cortínez LI, Absalom AR, Struys MMRF. A general purpose pharmacokinetic model for propofol. Anesth Analg 2014; 118:1221-37. [PMID: 24722258 DOI: 10.1213/ane.0000000000000165] [Citation(s) in RCA: 131] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
BACKGROUND Pharmacokinetic (PK) models are used to predict drug concentrations for infusion regimens for intraoperative displays and to calculate infusion rates in target-controlled infusion systems. For propofol, the PK models available in the literature were mostly developed from particular patient groups or anesthetic techniques, and there is uncertainty of the accuracy of the models under differing patient and clinical conditions. Our goal was to determine a PK model with robust predictive performance for a wide range of patient groups and clinical conditions. METHODS We aggregated and analyzed 21 previously published propofol datasets containing data from young children, children, adults, elderly, and obese individuals. A 3-compartmental allometric model was estimated with NONMEM software using weight, age, sex, and patient status as covariates. A predictive performance metric focused on intraoperative conditions was devised and used along with the Akaike information criteria to guide model development. RESULTS The dataset contains 10,927 drug concentration observations from 660 individuals (age range 0.25-88 years; weight range 5.2-160 kg). The final model uses weight, age, sex, and patient versus healthy volunteer as covariates. Parameter estimates for a 35-year, 70-kg male patient were: 9.77, 29.0, 134 L, 1.53, 1.42, and 0.608 L/min for V1, V2, V3, CL, Q2, and Q3, respectively. Predictive performance is better than or similar to that of specialized models, even for the subpopulations on which those models were derived. CONCLUSIONS We have developed a single propofol PK model that performed well for a wide range of patient groups and clinical conditions. Further prospective evaluation of the model is needed.
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Affiliation(s)
- Douglas J Eleveld
- From the *Department of Anesthesiology, University Medical Center Groningen, University of Groningen, The Netherlands; †Departmento de Anestesiología, Escuela de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile; and ‡Department of Anesthesia, Ghent University, Gent, Belgium
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Fischer JH, Sarto GE, Hardman J, Endres L, Jenkins TM, Kilpatrick SJ, Jeong H, Geller S, Deyo K, Fischer PA, Rodvold KA. Influence of gestational age and body weight on the pharmacokinetics of labetalol in pregnancy. Clin Pharmacokinet 2014; 53:373-83. [PMID: 24297680 PMCID: PMC4310214 DOI: 10.1007/s40262-013-0123-0] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
BACKGROUND AND OBJECTIVES Labetalol is frequently prescribed for the treatment of hypertension during pregnancy; however, the influence of pregnancy on labetalol pharmacokinetics is uncertain, with inconsistent findings reported by previous studies. This study examined the population pharmacokinetics of oral labetalol during and after pregnancy in women receiving labetalol for hypertension. METHODS Data were collected from 57 women receiving the drug for hypertension from the 12th week of pregnancy through 12 weeks postpartum using a prospective, longitudinal design. A sparse sampling strategy guided collection of plasma samples. Samples were assayed for labetalol by high-performance liquid chromatography. Estimation of population pharmacokinetic parameters and covariate effects was performed by nonlinear mixed effects modeling using NONMEM. The final population model was validated by bootstrap analysis and visual predictive check. Simulations were performed with the final model to evaluate the appropriate body weight to guide labetalol dosing. RESULTS Lean body weight (LBW) and gestational age, i.e. weeks of pregnancy, were identified as significantly influencing oral clearance (CL/F) of labetalol, with CL/F ranging from 1.4-fold greater than postpartum values at 12 weeks' gestational age to 1.6-fold greater at 40 weeks. Doses adjusted for LBW provide more consistent drug exposure than doses adjusted for total body weight. The apparent volumes of distribution for the central compartment and at steady-state were 1.9-fold higher during pregnancy. CONCLUSIONS Gestational age and LBW impact the pharmacokinetics of labetalol during pregnancy and have clinical implications for adjusting labetalol doses in these women.
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Affiliation(s)
- James H Fischer
- Department of Pharmacy Practice, College of Pharmacy, University of Illinois at Chicago, 833 S Wood Street, Room 164, Chicago, IL, 60612, USA,
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Yu S, Visvanathan T, Field J, Ward LC, Chapman I, Adams R, Wittert G, Visvanathan R. Lean body mass: the development and validation of prediction equations in healthy adults. BMC Pharmacol Toxicol 2013; 14:53. [PMID: 24499708 PMCID: PMC3833312 DOI: 10.1186/2050-6511-14-53] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2013] [Accepted: 10/09/2013] [Indexed: 12/22/2022] Open
Abstract
Background There is a loss of lean body mass (LBM) with increasing age. A low LBM has been associated with increased adverse effects from prescribed medications such as chemotherapy. Accurate assessment of LBM may allow for more accurate drug prescribing. The aims of this study were to develop new prediction equations (PEs) for LBM with anthropometric and biochemical variables from a development cohort and then validate the best performing PEs in validation cohorts. Methods PEs were developed in a cohort of 188 healthy subjects and then validated in a convenience cohort of 52 healthy subjects. The best performing anthropometric PE was then compared to published anthropometric PEs in an older (age ≥ 50 years) cohort of 2287 people. Best subset regression analysis was used to derive PEs. Correlation, Bland-Altman and Sheiner & Beal methods were used to validate and compare the PEs against dual X-ray absorptiometry (DXA)-derived LBM. Results The PE which included biochemistry variables performed only marginally better than the anthropometric PE. The anthropometric PE on average over-estimated LBM by 0.74 kg in the combined cohort. Across gender (male vs. female), body mass index (< 22, 22- < 27, 27- < 30 and ≥30 kg/m2) and age groups (50–64, 65–79 and ≥80 years), the maximum mean over-estimation of the anthropometric PE was 1.36 kg. Conclusions A new anthropometric PE has been developed that offers an alternative for clinicians when access to DXA is limited. Further research is required to determine the clinical utility and if it will improve the safety of medication use.
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Affiliation(s)
- Solomon Yu
- Aged and Extended Care Services, Level 8B Main Building, The Queen Elizabeth Hospital, Central Adelaide Local Health Network, 21 Woodville Road, 5011 Woodville South, SA, Australia.
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Goudra BG, Ortego A, Selassie M, Sinha AC. Lessons from providing total intravenous anesthesia (TIVA) to a morbidly obese patient (294 kg [648 lbs], body mass index 85.5 kg/m2). J Clin Anesth 2013; 25:428-429. [PMID: 23965200 DOI: 10.1016/j.jclinane.2013.03.008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2013] [Revised: 02/11/2013] [Accepted: 03/03/2013] [Indexed: 01/14/2023]
Affiliation(s)
- Basavana Gouda Goudra
- Department of Anesthesiology and Critical Care University of Pennsylvania Health System, Philadelphia PA 19104, USA.
| | - Alexandra Ortego
- Department of Anesthesiology and Critical Care University of Pennsylvania Health System, Philadelphia PA 19104, USA
| | - Meron Selassie
- Department of Anesthesiology and Critical Care University of Pennsylvania Health System, Philadelphia PA 19104, USA
| | - Ashish C Sinha
- Anesthesiology and Perioperative Medicine, Drexel University College of Medicine Philadelphia, PA 19102, USA
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Sigmond N, Baechtold M, Schumacher P, Hartwich V, Schnider T, Luginbühl M. Pharmacokinetic parameter sets of alfentanil revisited: optimal parameters for use in target controlled infusion and anaesthesia display systems. Br J Anaesth 2013; 111:197-208. [DOI: 10.1093/bja/aet049] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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