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Hemraj C, Kalaivani M, Binu H, Ramachandran R. Application of isotonic regression in estimating ED g and its 95% confidence interval by bootstrap method for a biased coin up-and-down sequential dose-finding design. Indian J Anaesth 2023; 67:828-831. [PMID: 37829784 PMCID: PMC10566662 DOI: 10.4103/ija.ija_431_23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2023] [Revised: 06/23/2023] [Accepted: 06/23/2023] [Indexed: 10/14/2023] Open
Affiliation(s)
- Chitralok Hemraj
- Department of Biostatistics, Pain Medicine and Critical Care, All India Institute of Medical Sciences, Delhi, India
| | - Mani Kalaivani
- Department of Biostatistics, Pain Medicine and Critical Care, All India Institute of Medical Sciences, Delhi, India
| | - Harsha Binu
- Department of Biostatistics, Pain Medicine and Critical Care, All India Institute of Medical Sciences, Delhi, India
| | - Rashmi Ramachandran
- Department of Biostatistics, Pain Medicine and Critical Care, All India Institute of Medical Sciences, Delhi, India
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Meng W, Kang F, Dong M, Wang S, Han M, Huang X, Wang S, Li J, Yang C. Remifentanil requirement for i-gel insertion is reduced in male patients with Parkinson's disease undergoing deep brain stimulator implantation: an up-and-down sequential allocation trial. BMC Anesthesiol 2022; 22:197. [PMID: 35751029 PMCID: PMC9229424 DOI: 10.1186/s12871-022-01735-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2021] [Accepted: 06/13/2022] [Indexed: 11/10/2022] Open
Abstract
Background Laryngeal mask airways have been widely used in clinical practice. The aim of this study was to investigate whether the remifentanil requirement for facilitation of i-gel insertion in Parkinson’s disease (PD) patients undergoing deep brain stimulation (DBS) surgery was different from that in non-PD (NPD) patients undergoing intracranial surgery. Study design An up-and-down sequential allocation trial. Methods Male patients aged between 40 and 64 years old were enrolled. The first patient in each group (PD and NPD) group received an effect-site concentration (Ce) of remifentanil (Minto pharmacokinetic model) of 4.0 ng.ml−1 during a target-controlled infusion (TCI) of 3.5 μg.ml−1 propofol (Marsh pharmacokinetic model). The next dose of remifentanil was determined by the response of the previous patient. The Ce of remifentanil required for i-gel insertion in 50% of patients (EC50) was estimated by the modified Dixon’s up-and-down method and by probit analysis. Results The PD group included 24 patients and the NPD group included 23. The EC50 of remifentanil for i-gel insertion during a TCI of 3.5 μg.ml−1 propofol estimated by the modified Dixon’s up-and-down method in PD patients (2.38 ± 0.65 ng.ml−1) was significantly lower than in NPD patients (3.21 ± 0.49 ng.ml−1) (P = 0.03). From the probit analysis, the EC50 and EC95 (effective Ce in 95% of patients) of remifentanil were 1.95 (95% CI 1.52–2.36) ng.ml−1 and 3.12 (95% CI 2.53–5.84) ng.ml−1 in PD patients and 2.85 (95% CI 2.26–3.41) ng.ml−1 and 4.57 (95% CI 3.72–8.54) ng.ml−1 in NPD patients, respectively. Conclusions The remifentanil requirement for successful i-gel insertion is reduced in male PD patients undergoing DBS implantation during propofol TCI induction. Clinicians should closely monitor the remifentanil requirement in patients with PD. Trial registration Registered at http://www.chictr.org.cn (ChiCTR1900021760).
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Affiliation(s)
- Wenjun Meng
- Department of Anesthesiology, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, 230036, China
| | - Fang Kang
- Department of Anesthesiology, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, 230036, China
| | - Meirong Dong
- Department of Anesthesiology, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, 230036, China
| | - Song Wang
- Department of Anesthesiology, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, 230036, China
| | - Mingming Han
- Department of Anesthesiology, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, 230036, China
| | - Xiang Huang
- Department of Anesthesiology, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, 230036, China
| | - Sheng Wang
- Department of Anesthesiology, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, 230036, China
| | - Juan Li
- Department of Anesthesiology, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, 230036, China.
| | - Chengwei Yang
- Department of Anesthesiology, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, 230036, China.
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Optimized Planning and Evaluation of Dental Implant Fatigue Testing: A Specific Software Application. BIOLOGY 2020; 9:biology9110372. [PMID: 33142807 PMCID: PMC7693306 DOI: 10.3390/biology9110372] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/04/2020] [Revised: 10/29/2020] [Accepted: 10/30/2020] [Indexed: 11/17/2022]
Abstract
Mechanical complications in implant-supported fixed dental prostheses are often related to implant and prosthetic design. Although the current ISO 14801 provides a framework for the evaluation of dental implant mechanical reliability, strict adherence to it may be difficult to achieve due to the large number of test specimens which it requires as well as the fact that it does not offer any probabilistic reference for determining the endurance limit. In order to address these issues, a new software program called ProFatigue is presented as a potentially powerful tool to optimize fatigue testing of implant-supported prostheses. The present work provides a brief description of some concepts such as load, fatigue and stress-number of cycles to failure curves (S-N curves), before subsequently describing the current regulatory situation. After analyzing the two most recent versions of the ISO recommendation (from 2008 and 2016), some limitations inherent to the experimental methods which they propose are highlighted. Finally, the main advantages and instructions for the correct implementation of the ProFatigue free software are given. This software will contribute to improving the performance of fatigue testing in a more accurate and optimized way, helping researchers to gain a better understanding of the behavior of dental implants in this type of mechanical test.
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Monks DT, Palanisamy A. Intrapartum oxytocin: time to focus on longer term consequences? Anaesthesia 2019; 74:1219-1222. [DOI: 10.1111/anae.14746] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/30/2019] [Indexed: 01/15/2023]
Affiliation(s)
- D. T. Monks
- Department of Anesthesiology Washington University School of Medicine St. Louis MIUSA
| | - A. Palanisamy
- Department of Anesthesiology Washington University School of Medicine St. Louis MIUSA
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Lagos-Carvajal A, Queiroz-Williams P, da Cunha A, Liu CC. Determination of midazolam dose for co-induction with alfaxalone in sedated cats. Vet Anaesth Analg 2019; 46:299-307. [PMID: 30928240 DOI: 10.1016/j.vaa.2019.01.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2018] [Revised: 12/23/2018] [Accepted: 01/09/2019] [Indexed: 10/27/2022]
Abstract
OBJECTIVE To investigate the median effective dose 50 (ED50) of midazolam required for endotracheal intubation when used for co-induction of anesthesia with a low dose of alfaxalone in sedated cats. STUDY DESIGN Randomized up-and-down study. ANIMALS A group of 14 mixed-breed cats (eight males, six females), aged 5-12 years and weighing 4.4-6.8 kg. METHODS The cats were randomly assigned in a sequential allocation numbers from one to 14. Cats were sedated with dexmedetomidine (3 μg kg-1) and methadone (0.3 mg kg-1) intramuscularly. After 15 minutes, the quality of sedation was subjectively evaluated. Anesthesia induction was performed by intravenous (IV) administration of alfaxalone (0.25 mg kg-1) over a 60 second interval, followed by another 60 second interval, and then an IV dose of midazolam was administered over a 5 second interval. The initial midazolam dose was 0.3 mg kg-1; then, the midazolam dose was adjusted by ±0.1 mg kg-1 for each consecutive cat based on successful or unsuccessful endotracheal intubation of the previous animal following an up-and-down method. This sequence was followed until six nonsequential crossovers were observed. Crossover was defined as two opposite outcomes in two sequential animals. Data were analyzed using isotonic regression with bootstrapping for determination of midazolam ED50 and logistic regression for correlations (p < 0.05). RESULTS Overall, six independent crossovers were found, and ED50 of midazolam was 0.08 ± 0.04 mg kg-1. Sedation score and successful tracheal intubation had a strong positive correlation (p = 0.02). CONCLUSIONS AND CLINICAL RELEVANCE This study determined that 0.08 ± 0.04 mg kg-1 of midazolam co-administered with 0.25 mg kg-1 of alfaxalone IV allowed smooth endotracheal intubation in half of the cats sedated with methadone and dexmedetomidine at the doses used in this study.
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Affiliation(s)
- Angie Lagos-Carvajal
- Department of Veterinary Clinical Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge, LA, USA
| | - Patricia Queiroz-Williams
- Department of Veterinary Clinical Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge, LA, USA.
| | - Anderson da Cunha
- Department of Veterinary Clinical Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge, LA, USA
| | - Chin-Chi Liu
- Department of Veterinary Clinical Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge, LA, USA
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Remifentanil Requirement for Inhibiting Responses to Tracheal Intubation and Skin Incision Is Reduced in Patients With Parkinson's Disease Undergoing Deep Brain Stimulator Implantation. J Neurosurg Anesthesiol 2017; 28:303-8. [PMID: 26368663 DOI: 10.1097/ana.0000000000000229] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND Parkinson's disease (PD) is a common neurodegenerative disease affecting the quality of life in the elderly. We speculated that PD patients might have abnormal pharmacodynamics due to the degenerative neural system, and the present study was performed to investigate the pharmacodynamics of remifentanil in PD patients. MATERIALS AND METHODS Two arms of patients were recruited, including 31 PD patients undergoing pulse generator placement after deep brain stimulator implantation and 31 pair-controlled patients undergoing intracranial surgery without PD (NPD). Patients were anesthetized with target-controlled infusion of propofol and remifentanil. The effective concentration of remifentanil to inhibit responses to intubation and skin incision in 50% and 95% patients (EC50 and EC95) was determined by the up and down method. RESULTS Demographic data, bispectral index, and hemodynamic values were similar between the PD and the NPD groups. The average remifentanil concentration used in the PD group for tracheal intubation is significantly lower than in the NPD group (P<0.001). The EC50 for inhibiting the response to tracheal intubation were 1.86 ng/mL (95% confidential interval [CI], 1.77-1.96 ng/mL) in the PD group and 3.20 ng/mL (95% CI, 3.13-3.27 ng/mL) in the NPD group. The average remifentanil concentration used in the PD group for skin incision is significantly lower than in the NPD group (P<0.001). EC50 for inhibiting the response to skin incision were 2.17 ng/mL (95% CI, 2.09-2.25 ng/mL) in the PD group and 3.09 ng/mL (95% CI, 3.02-3.17 ng/mL) in the NPD group. CONCLUSIONS The remifentanil concentrations required for inhibiting responses to tracheal intubation and skin incision are reduced markedly in PD patients undergoing pulse generator placement (NCT01992692).
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Görges M, Zhou G, Brant R, Ansermino JM. Sequential allocation trial design in anesthesia: an introduction to methods, modeling, and clinical applications. Paediatr Anaesth 2017; 27:240-247. [PMID: 28211193 DOI: 10.1111/pan.13088] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 12/01/2016] [Indexed: 02/06/2023]
Abstract
Estimation of the dose-response curve for new anesthetic protocols typically focuses on identifying minimum effective doses. The application of a sequential experimental method is appropriate, as it minimizes sample size requirements by updating dose assignments based on information accrued from successive subjects. One approach is the up-and-down method for estimating the median effective dose in a patient population (ED50 ). Designs better suited for achieving greater than 50% effectiveness, include the biased coin approach, and continual reassessment method. In this review we introduce different sequential design methods, provide examples of their use, and show through simulation how the method employed influences sample size and the accuracy of the estimated dose. Simulation studies are presented to illustrate the effects of dose parameter and stopping rule choice for up-and-down method and biased coin approach. For continual reassessment method, the effects of assumed dose-response model, prior guess, and cohort size are simulated. A binary response regression curve was fit to the data in Saidman and Eger's endtidal halothane dose-finding study to provide a dose-response curve for generating simulations. A range of options exist when designing a study using sequential allocation with biased coin approach or continual reassessment method. Method choice influences the required sample size and confidence in estimated effect. In the halothane example, up-and-down method decreases the required sample size by 20-30% when the choice of design parameters is optimal. For both up-and-down method and biased coin approach designs, greater sample sizes, arising from adjusted stopping criteria, might be required to achieve reliable estimates. The continual reassessment method is only efficient if a limited range of doses can be chosen a priori. In conclusion the up-and-down method can be more efficient than nonsequential designs for the estimation of the median dose/intervention level for a given intervention (ED50 ). The biased coin approach or continual reassessment method are preferred for the estimation of higher or lower tail quantiles such as ED90 or ED10 . Continual reassessment method may be superior if knowledge of the dose-response relationship is available for the drug of interest.
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Affiliation(s)
- Matthias Görges
- Department of Anesthesiology, Pharmacology, and Therapeutics, The University of British Columbia, Vancouver, Canada.,Research Institute, BC Children's Hospital, Vancouver, Canada
| | - Guohai Zhou
- Department of Statistics, The University of British Columbia, Vancouver, Canada
| | - Rollin Brant
- Department of Statistics, The University of British Columbia, Vancouver, Canada
| | - J Mark Ansermino
- Department of Anesthesiology, Pharmacology, and Therapeutics, The University of British Columbia, Vancouver, Canada
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Liu H, Huang Y, Diao M, Li H, Ma Y, Lin X, Zhou J. Determination of the 90% effective dose (ED90) of phenylephrine for hypotension during elective cesarean delivery using a continual reassessment method. Eur J Obstet Gynecol Reprod Biol 2015; 194:136-40. [PMID: 26372882 DOI: 10.1016/j.ejogrb.2015.07.001] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2015] [Revised: 06/24/2015] [Accepted: 07/06/2015] [Indexed: 11/29/2022]
Abstract
OBJECTIVE The purpose of this study was to determine, by continual reassessment, the 90% effective dose (ED90) of phenylephrine for hypotension after combined spinal-epidural anesthesia. STUDY DESIGN Term pregnant women scheduled for elective cesarean delivery received combined spinal epidural anesthesia. Subjects received phenylephrine at one of 6 incremental doses ranging from 60 to 160μg (n=3 for each dose). While the first cohort received a conservative, predetermined dose of 60μg, subsequent cohorts received phenylephrine doses determined using Bayesian-based software. One of the predetermined bolus doses of phenylephrine was given in the event of both hypotension [defined as systolic blood pressure (SBP)<80% of baseline or below 100mmHg] and tachycardia [defined as heart rate >120% of baseline or >100beatsmin(-1)]. Treatment was considered successful if SBP returned to within 80% of the baseline or ≥100mmHg within 2min. RESULTS Twenty-four subjects with hypotension and tachycardia were included. T6 block was achieved within 15min in 20 patients and after additional epidural chloroprocaine in the remaining four. The estimated ED90 was 100μg, with a response probability of 90.7% (95% CI 74.1-99.5%). Treatment was successful in 20 patients. Probability of success at each bolus dose (in μg) was as follows: 60, 58.9%; 80, 80.3%; 100, 90.7%; 120, 95.5%; 140, 98.3%; and 160, 99.2%. CONCLUSIONS The ED90 of a phenylephrine bolus dose for hypotension in term pregnant women is approximately 100μg, based on continual reassessment.
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Ultrasound-guided tranversus abdominis plane block for herniorrhaphy in children: what is the optimal dose of levobupivacaine? Eur J Anaesthesiol 2015; 32:366. [PMID: 25793759 DOI: 10.1097/eja.0000000000000241] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
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Minimum Effective Volume of Combined Lidocaine-Bupivacaine for Analgesic Subparaneural Popliteal Sciatic Nerve Block. Reg Anesth Pain Med 2014; 39:108-11. [DOI: 10.1097/aap.0000000000000051] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Sverdlov O, Wong WK, Ryeznik Y. Adaptive clinical trial designs for phase I cancer studies. STATISTICS SURVEYS 2014. [DOI: 10.1214/14-ss106] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Lilot M, Meuret P, Bouvet L, Caruso L, Dabouz R, Deléat-Besson R, Rousselet B, Thouverez B, Zadam A, Allaouchiche B, Boselli E. Hypobaric spinal anesthesia with ropivacaine plus sufentanil for traumatic femoral neck surgery in the elderly: a dose-response study. Anesth Analg 2013; 117:259-64. [PMID: 23592605 DOI: 10.1213/ane.0b013e31828f29f8] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
BACKGROUND In this randomized, prospective trial, we sought to determine the effective dose of hypobaric ropivacaine with sufentanil providing 95% success (ED95) in spinal anesthesia for traumatic femoral neck surgery in the elderly. METHODS Sixty-eight elderly patients with unilateral hip fracture randomly received 6, 8, 10, or 12 mg spinal hypobaric ropivacaine combined with 5 µg sufentanil. Patients remained in a lateral position for 15 minutes after spinal injection. The dose was considered successful if a unilateral sensory block >T12 was achieved, and there was no need for additional analgesia or conversion to general anesthesia. The ED95 was determined using logit analysis. The incidence of severe and very severe hypotension (systolic blood pressure decrease by >30% and >40% baseline, respectively) and the use of remifentanil were compared among groups using χ(2) test for trend. RESULTS Three patients were excluded because of failure to reach the subarachnoid space. No differences in baseline demographic data were observed among groups. The ED95 for hypobaric ropivacaine was determined to be 9 mg (95% confidence interval, 8-14). Increasing doses of ropivacaine (6, 8, 10, and 12 mg) demonstrated a positive trend with respect to incidence of hypotension (53%, 47%, 87%, and 81%, P = 0.0004) and a negative trend with respect to the use of remifentanil (41%, 12%, 0%, and 0%, P = 0.0004). A significant difference in the level of sensory block (P < 0.0001) was observed among operative and nonoperative sides but not among ropivacaine dosing groups (P = 0.16). No difference in motor blockade, incidence of very severe hypotension, total dose of ephedrine, duration of surgery, patient satisfaction, operating conditions, or surgeon satisfaction scores was observed among groups. No cases of bradycardia were observed. No patient had a preoperative sensory level <T12 after 15 minutes in the lateral decubitus position, and no cases were converted to general anesthesia. There was no difference in undesirable outcomes or postoperative troponin values among groups. CONCLUSIONS The effective dose of hypobaric ropivacaine combined with sufentanil 5 µg providing 95% success in spinal anesthesia for traumatic femoral neck surgery in the elderly is ED95 = 9 mg (95% confidence interval, 8-14). Using doses exceeding the ED95 may increase the incidence of hypotension. If doses less than the ED95 are chosen, the use of additional analgesia may be necessary.
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Affiliation(s)
- Marc Lilot
- Service d'anesthésie-réanimation, Hôpital Édouard Herriot, 5 place d'Arsonval, 69003 Lyon, France.
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Minimum Effective Volume of Lidocaine for Double-Injection Ultrasound-Guided Axillary Block. Reg Anesth Pain Med 2013; 38:16-20. [DOI: 10.1097/aap.0b013e3182707176] [Citation(s) in RCA: 74] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Do WS, Kim TK, Kim HK, Kim CH. The EC(50) of remifentanil to minimize the cardiovascular changes during head holder pinning in neurosurgery. Korean J Anesthesiol 2012; 63:327-33. [PMID: 23115685 PMCID: PMC3483491 DOI: 10.4097/kjae.2012.63.4.327] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2012] [Revised: 04/05/2012] [Accepted: 05/09/2012] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND During neuroanesthesia, head holder pinning commonly results in sympathetic stimulation manifested by hemodynamic changes, such as increased heart rate and arterial blood pressure. Remifentanil has been used successfully to control acute autonomic responses during neurosurgical procedures. The objective of this study was to determine effect-site concentration of remifentanil for suppressing the hemodynamic response to head holder pinning with the probability of 50% (EC(50)). METHODS Forty-one ASA physical status I or II patients, between the ages of 20-70, who were scheduled for neurosurgery were recruited into this study. After arrival in the operating room, standard monitoring was applied throughout the study, which included a bispectral index monitor. Both propofol and remifentanil were administered by Target-control infusion device. The Dixon "up-and-down" sequential allocation method was used to determine the EC(50) of remifentanil. RESULTS The EC(50) of remifentanil was 2.19 ± 0.76 ng/ml by the turning point estimate (TPE). In probit analysis, EC(50) was 2.42 ng/ml (95% CI : -0.62-4.66) and EC(95) was 5.70 ng/ml (95% CI : 4.02-67.53). The EC(50) estimator comes from isotonic regression is 2.90 ng/ml (95% CI : 1.78-3.65). The EC(95) estimator comes from isotonic regression is 4.28 ng/ml (95% CI : 3.85-4.41). CONCLUSIONS This study showed that EC(50) of remifentanil was 2.19 ± 0.76 ng/ml by TPE. EC(50) was 2.42 ng/ml (95% CI -0.62-4.66) in probit analysis, as back up analysis. The EC(50) estimator comes from isotonic regression is 2.90 ng/ml (95% CI : 1.78-3.65).
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Affiliation(s)
- Wang Seok Do
- Department of Anesthesia and Pain Medicine, School of Medicine, Pusan National University, Busan, Korea
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Abstract
BACKGROUND The aim of this study was to determine the minimum effective volume of lidocaine 1.5% with epinephrine 5 μg/mL in 90% of patients (MEV90) for double-injection ultrasound-guided supraclavicular block (SCB). METHODS Using an in-plane technique and a lateral to medial direction, a double-injection ultrasound-guided SCB was performed. A 17-gauge, 8-cm Tuohy needle was initially advanced until its tip was positioned at the intersection of the first rib and subclavian artery ("corner pocket"). Half the volume of lidocaine was injected in this location. Subsequently, the needle was redirected toward the neural cluster formed by the trunks and divisions of the brachial plexus. The remaining volume of lidocaine was deposited in this location. Volume assignment was carried out using a biased coin design up-and-down sequential method, where the total volume of local anesthetic administered to each patient depended on the response of the previous one. In case of failure, the next subject received a higher volume (defined as the previous volume with an increment of 2.5 mL). If the previous patient had a successful block, the next subject was randomized to a lower volume (defined as the previous volume with a decrement of 2.5 mL), with a probability of b = 0.11, or the same volume, with a probability of 1 - b = 0.89. Each increment or decrement was evenly distributed between the "corner pocket" (1.25 mL) and neural cluster (1.25 mL). Lidocaine 1.5% with epinephrine 5 μg/mL was used in all subjects. Success was defined, at 30 minutes, as a minimal score of 14 of 16 points using a composite scale encompassing sensory and motor block. Patients undergoing surgery of the elbow, forearm, wrist, or hand were prospectively enrolled until 45 successful blocks were obtained. RESULTS Fifty-four patients were included in the study. Using isotonic regression and bootstrap confidence interval, the MEV90 for double-injection ultrasound-guided SCB was estimated to be 32 mL (95% confidence interval, 30-34 mL). All patients with a minimal composite score of 14 points at 30 minutes achieved surgical anesthesia intraoperatively. CONCLUSIONS For double-injection ultrasound-guided SCB, the MEV90 of lidocaine 1.5% with epinephrine 5 μg/mL is 32 mL. Further dose finding studies are required for other concentrations of lidocaine, other local anesthetic agents and single-injection techniques.
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Minimum Effective Volume of Lidocaine for Ultrasound-Guided Infraclavicular Block. Reg Anesth Pain Med 2011; 36:190-4. [DOI: 10.1097/aap.0b013e31820d4266] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Frawley G, Smith K, Ingelmo P. Relative potencies of bupivacaine, levobupivacaine, and ropivacaine for neonatal spinal anaesthesia. Br J Anaesth 2009; 103:731-8. [DOI: 10.1093/bja/aep259] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
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Ingelmo P, Frawley G, Astuto M, Duffy C, Donath S, Disma N, Rosano G, Fumagalli R, Gullo A. Relative analgesic potencies of levobupivacaine and ropivacaine for caudal anesthesia in children. Anesth Analg 2009; 108:805-13. [PMID: 19224787 DOI: 10.1213/ane.0b013e3181935aa5] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
BACKGROUND Comparing relative potency of new local anesthetics, such as levobupivacaine and ropivacaine, by the minimum local analgesic concentration model has not been described for caudal anesthesia. Therefore, we performed a prospective, randomized, double-blind study to determine the minimum local analgesic concentrations of a caudal single shot of ropivacaine and levobupivacaine in children and to describe the upper dose-response curve. METHODS We performed a two-stage prospective, randomized, double-blind study comparing the dose-response curves of caudal ropivacaine and levobupivacaine in children. In phase 1, 80 boys were randomized to receive either ropivacaine or levobupivacaine. In the second phase a further 32 patients were randomly allocated to receive caudal anesthesia with doses designed to delineate the upper dose-response range (the 50% effective dose [ED(50)]-ED(95) range). RESULTS There were no significant differences in ED(50) values for caudal ropivacaine and levobupivacaine. The ED(50) for levobupivacaine estimated from the Dixon Massey method was 0.069% (95% CI 0.056%-0.082%) and for ropivacaine was 0.075% (95% CI 0.058%-0.092%). Estimated by isotonic regression the ED(50) and ED(95) respectively of levobupivacaine were 0.068 (0.04-0.09) and 0.20% (95% CI 0.16%-0.24%). For ropivacaine ED 50 and ED95 were 0.066 (0.033-0.098) and 0.225% (95% CI 0.21%-0.24%). CONCLUSIONS In children receiving one minimum alveolar anesthetic concentration of sevoflurane, there were no significant differences in the ED(50) for caudal levobupivacaine and ropivacaine. The potency ratio at ED(50) was 0.92 and 0.89 at ED(95), indicating that caudal levobupivacaine and ropivacaine have a similar potency.
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Affiliation(s)
- Pablo Ingelmo
- Department of Perioperative Medicine and Intensive, A.O. San Gerardo, Monza, Italy
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19
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Tzvetanov T, Womelsdorf T. Predicting human perceptual decisions by decoding neuronal information profiles. BIOLOGICAL CYBERNETICS 2008; 98:397-411. [PMID: 18373103 PMCID: PMC2799009 DOI: 10.1007/s00422-008-0226-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/11/2006] [Accepted: 03/06/2008] [Indexed: 05/26/2023]
Abstract
Perception relies on the response of populations of neurons in sensory cortex. How the response profile of a neuronal population gives rise to perception and perceptual discrimination has been conceptualized in various ways. Here we suggest that neuronal population responses represent information about our environment explicitly as Fisher information (FI), which is a local measure of the variance estimate of the sensory input. We show how this sensory information can be read out and combined to infer from the available information profile which stimulus value is perceived during a fine discrimination task. In particular, we propose that the perceived stimulus corresponds to the stimulus value that leads to the same information for each of the alternative directions, and compare the model prediction to standard models considered in the literature (population vector, maximum likelihood, maximum-a-posteriori Bayesian inference). The models are applied to human performance in a motion discrimination task that induces perceptual misjudgements of a target direction of motion by task irrelevant motion in the spatial surround of the target stimulus (motion repulsion). By using the neurophysiological insight that surround motion suppresses neuronal responses to the target motion in the center, all models predicted the pattern of perceptual misjudgements. The variation of discrimination thresholds (error on the perceived value) was also explained through the changes of the total FI content with varying surround motion directions. The proposed FI decoding scheme incorporates recent neurophysiological evidence from macaque visual cortex showing that perceptual decisions do not rely on the most active neurons, but rather on the most informative neuronal responses. We statistically compare the prediction capability of the FI decoding approach and the standard decoding models. Notably, all models reproduced the variation of the perceived stimulus values for different surrounds, but with different neuronal tuning characteristics underlying perception. Compared to the FI approach the prediction power of the standard models was based on neurons with far wider tuning width and stronger surround suppression. Our study demonstrates that perceptual misjudgements can be based on neuronal populations encoding explicitly the available sensory information, and provides testable neurophysiological predictions on neuronal tuning characteristics underlying human perceptual decisions.
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Affiliation(s)
- Tzvetomir Tzvetanov
- Cognitive Neuroscience Laboratory, German Primate Center, Kellnerweg 4, 37077 Göttingen, Germany
- Max-Planck Institute for Dynamics and Self-Organization, Bunsenstrasse 10, 37073 Göttingen, Germany
- Bernstein Center for Computational Neuroscience, Göttingen, Germany
| | - Thilo Womelsdorf
- F.C. Donders Centre for Cognitive Neuroimaging, Radboud University Nijmegen, Kapittelweg 29, 6525 EN Nijmegen, The Netherlands
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Pace NL, Stylianou MP. Advances in and limitations of up-and-down methodology: a précis of clinical use, study design, and dose estimation in anesthesia research. Anesthesiology 2007; 107:144-52. [PMID: 17585226 DOI: 10.1097/01.anes.0000267514.42592.2a] [Citation(s) in RCA: 287] [Impact Index Per Article: 16.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Sequential design methods for binary response variables exist for determination of the concentration or dose associated with the 50% point along the dose-response curve; the up-and-down method of Dixon and Mood is now commonly used in anesthesia research. There have been important developments in statistical methods that (1) allow the design of experiments for the measurement of the response at any point (quantile) along the dose-response curve, (2) demonstrate the risk of certain statistical methods commonly used in literature reports, (3) allow the estimation of the concentration or dose-the target dose-associated with the chosen quantile without the assumption of the symmetry of the tolerance distribution, and (4) set bounds on the probability of response at this target dose. This article details these developments, briefly surveys current use of the up-and-down method in anesthesia research, reanalyzes published reports using the up-and-down method for the study of the epidural relief of pain during labor, and discusses appropriate inferences from up-and-down method studies.
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Affiliation(s)
- Nathan L Pace
- Department of Anesthesiology, University of Utah, Salt Lake City, Utah 84132-2304, USA.
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21
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Hall DB, Meier U, Diener HC. A group sequential adaptive treatment assignment design for proof of concept and dose selection in headache trials. Contemp Clin Trials 2005; 26:349-64. [PMID: 15911469 DOI: 10.1016/j.cct.2005.02.001] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2004] [Revised: 08/20/2004] [Accepted: 02/02/2005] [Indexed: 10/25/2022]
Abstract
The trial objective was to test whether a new mechanism of action would effectively treat migraine headaches and to select a dose range for further investigation. The motivation for a group sequential, adaptive, placebo-controlled trial design was (1) limited information about where across the range of seven doses to focus attention, (2) a need to limit sample size for a complicated inpatient treatment and (3) a desire to reduce exposure of patients to ineffective treatment. A design based on group sequential and up and down designs was developed and operational characteristics were explored by trial simulation. The primary outcome was headache response at 2 h after treatment. Groups of four treated and two placebo patients were assigned to one dose. Adaptive dose selection was based on response rates of 60% seen with other migraine treatments. If more than 60% of treated patients responded, then the next dose was the next lower dose; otherwise, the dose was increased. A stopping rule of at least five groups at the target dose and at least four groups at that dose with more than 60% response was developed to ensure that a selected dose would be statistically significantly (p=0.05) superior to placebo. Simulations indicated good characteristics in terms of control of type 1 error, sufficient power, modest expected sample size and modest bias in estimation. The trial design is attractive for phase 2 clinical trials when response is acute and simple, ideally binary, placebo comparator is required, and patient accrual is relatively slow allowing for the collection and processing of results as a basis for the adaptive assignment of patients to dose groups. The acute migraine trial based on this design was successful in both proof of concept and dose range selection.
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Affiliation(s)
- David B Hall
- Department of Biometrics and Data Management, Boehringer Ingelheim Pharmaceuticals, P.O. Box 368, Ridgefield, CT 06877, USA.
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22
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Vågerö M. A remark on small-sample properties of logistic regression in three-point designs. J Biopharm Stat 2000; 10:573-87. [PMID: 11104394 DOI: 10.1081/bip-100101985] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Nottingham and Birch (1) recently alleged that the maximum likelihood (ML) estimator beta of the steepness parameter in a logistic regression model could be seriously underestimated. They based their conclusion on a simulation study, investigating in particular a small-sample three-point design with a relatively large spacing between the doses. In the present work we study such situations in more detail and use complete enumeration to find the exact properties of the ML estimators. The result presented here show that the allegation by Nottingham and Birch was misleading. There is a substantial probability for an infinite outcome of beta, which appears to have been neglected by Nottingham and Birch. In fact, it will be demonstrated that the asymptotic normal approximation for beta fits quite well even with small samples, except in the upper tail where outcomes are infinite instead of large finite. The consequences for coverage probabilities of confidence intervals for both of the regression parameters are elucidated.
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Affiliation(s)
- M Vågerö
- Department of Biostatistics and Data Management, Pharmacia & Upjohn AB, Stockholm University, Sweden
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