Propofol Cp Research Articles

Determining the Target Concentration of Propofol for Sedation in Patients Undergoing Endoscopic Retrograde Cholangiopancreatography: A Target-Controlled Infusion Approach.

Introduction Endoscopic retrograde cholangiopancreatography (ERCP) is vital for diagnosing and treating biliary and pancreatic diseases, necessitating deep sedation typically achieved through total intravenous anesthesia. Propofol, with its favorable pharmacokinetic profile, is the preferred sedative, but conventional administration methods of mg/kg boluses or infusion rates pose challenges. Target-controlled infusion (TCI) systems offer a solution that ensures precise dose delivery of propofol. Despite its widespread use, the literature lacks specific guidance on the target plasma concentration (Cp) of propofol for sedation in patients undergoing ERCP. Methods A prospective interventional study was conducted at the Institute of Liver and Biliary Sciences, Delhi, India to determine the target Cp of propofol for sedation during ERCP. The study enrolled 86 American Society of Anesthesiologists (ASA) grade I and II patients aged 18-70 years. The primary objective was to establish the optimal propofol concentration for sedation as guided by a bispectral index (BIS) value of 60-70. Secondary outcomes included induction time, recovery time, total propofol consumption, and the occurrence of adverse events (if any). The Marsh pharmacokinetic model guided the TCI pump, adjusting Cp until the target sedation was achieved. Results The mean Cp of propofol to maintain the BIS value 60-70 was 2.21 ± 0.42 µg/ml. Age-wise analysis revealed variations, emphasizing the need for individualized dosing. Induction time was 4.21 ± 0.68 minutes; recovery times were seven minutes (median, IQR: 5-10 minutes) for BIS >80 and seven minutes (median, IQR: 5-10 minutes) for achieving a Modified Observer's Assessment of Alertness/Sedation score of ≥5. The mean propofol consumption was 6.24 mg/kg/hr. Side effects were minimal, with 1.16% experiencing transient hypoxia and hypotension. Conclusion The study establishes a mean target propofol concentration of 2.21 ± 0.42 µg/ml for sedation in ASA I and II patients undergoing ERCP.

The effect of preoperative sleep quality on the target plasma concentration of propofol and postoperative sleep in patients undergoing painless gastroscopy

BackgroundThis study aims to investigate the effect of preoperative sleep quality on the target plasma concentration of propofol and postoperative sleep in patients undergoing painless gastroscopy.MethodsNinety-three outpatients aged 45 to 64 years with body mass index (BMI) of 18.5–30 kg/m2 and ASA grades of I or II, who underwent painless gastroscopy, were selected. All patients were evaluated by the Athens insomnia scale (AIS) before the painless gastroscopy. The patients were divided into two groups according to the AIS score evaluated before painless gastroscopy: normal sleep group (group N, AIS score < 4 points, 47 cases) and sleep disorder group (group D, AIS score > 6 points, 46 cases). The target-controlled infusion (TCI) of propofol (Marsh model) was used for general anesthesia, the Bispectral index (BIS) was used to monitor the depth of anesthesia, and the BIS was maintained between 50 and 65 during the painless gastroscopy. The target plasma concentration (Cp) of propofol was recorded when the patient’s eyelash reflex disappeared (T1), before the painless gastroscopy (T2), at the time of advancing the gastroscope (T3) and during the painless gastroscopy (T4), and the infusion rate per body surface area of propofol was calculated. The patient’s AIS score was followed up by telephone at day 1, day 3, 1 week, and 1 month after the painless gastroscopy to assess the postoperative sleep of the patient. The occurrence of adverse reactions during the painless gastroscopy was recorded; the patient’s satisfaction and the endoscopist’s satisfaction with the anesthesia effect were compared between the two groups.ResultsCompared with group N, the Cp at each time point and the infusion rate per body surface area of propofol in group D was increased significantly (P < 0.05); compared with the AIS scores before the painless gastroscopy, the AIS scores of the two groups of patients were significantly increased day 1 after the painless gastroscopy (P < 0.05); there were no significant differences in the AIS scores of the two groups at day 3, 1 week, and 1 month after the painless gastroscopy (P > 0.05). There were no statistically significant differences in the occurrence of adverse reactions and the patient’s satisfaction and the endoscopist’s satisfaction with the anesthesia effect between the two groups (P > 0.05).ConclusionThe preoperative sleep disturbance will increase the Cp and the infusion rate per body surface area of propofol in patients undergoing painless gastroscopy. Propofol only affects the patients’ sleep for day 1 after the painless gastroscopy.Trial registrationChinese Clinical Trial Registry (ChiCTR2100045332) on 12/04/2021.

Intraoperative hand strength as an indicator of consciousness during awake craniotomy: a prospective, observational study

Awake craniotomy enables mapping and monitoring of brain functions. For successful procedures, rapid awakening and the precise evaluation of consciousness are required. A prospective, observational study conducted to test whether intraoperative hand strength could be a sensitive indicator of consciousness during the awake phase of awake craniotomy. Twenty-three patients who underwent awake craniotomy were included. Subtle changes of the level of consciousness were assessed by the Japan Coma Scale (JCS). The associations of hand strength on the unaffected side with the predicted plasma concentration (Cp) of propofol, the bispectral index (BIS), and the JCS were analyzed. Hand strength relative to the preoperative maximum hand strength on the unaffected side showed significant correlations with the Cp of propofol (ρ = − 0.219, p = 0.007), the BIS (ρ = 0.259, p = 0.002), and the JCS (τ = − 0.508, p = 0.001). Receiver operating characteristic curve analysis for discriminating JCS 0–1 and JCS ≥ 2 demonstrated that the area under the curve was 0.76 for hand strength, 0.78 for Cp of propofol, and 0.66 for BIS. With a cutoff value of 75% for hand strength, the sensitivity was 0.76, and the specificity was 0.67. These data demonstrated that hand strength is a useful indicator for assessing the intraoperative level of consciousness during awake craniotomy.

AWAKENING CHARACTERISTICS AND RECOVERY OF COGNITIVE FUNCTION IN PATIENTS UNDERGOING SHORT SURGICAL PROCEDURES: COMPARISON BETWEEN DESFLURANE AND PROPOFOL

Objectives: Early awakening and recovery of the cognitive function improves post-operative outcome and early discharge of the patients. Desflurane and Propofol offer rapid emergence from anesthesia. We compared the awakening and recovery of cognitive function between these two agents. Methods: A total of 50 patients aged 30–60 years belonging to ASA 1 and 2 were studied. In both the groups baseline, Mini Mental State Examination (MMSE) score was recorded and were induced with Target controlled infusion (TCI) of Propofol to achieve plasma site concentration (Cp) of 6 mcg/ml. Group P continued with TCI Propofol Cp 3 mcg ml-1 and in group D, TCI was stopped and started Desflurane 6% end tidal concentration followed by Desflurane 3%. Hemodynamic variables were noted and after stopping the agent, time to eye open, squeeze hands, removal of laryngeal mask airway, state name, and modified Aldrete score were noted. MMSE score was recorded 1, 6, and 24 h postoperatively. Results: Awakening time was significantly shorter in duration in Desflurane group compared to Propofol. The mean time to eye open in the Propofol group was 10.41±2:31 min and Desflurane group was 06.21±01.42 min (***p=0.000). There was an increase in the mean MMSE score postoperatively at 6 h and 24 h interval when compared to the baseline within the groups. However, there was no difference in recovery of cognitive function between the two groups. Conclusion: The use of inhalational agent Desflurane provided shorter awakening time than intravenous Propofol in short surgical procedures but the recovery of cognitive function was comparable. There were no significant side effects.

Comparison between continuous rate infusion and target-controlled infusion of propofol in dogs: a randomized clinical trial

ObjectiveTo compare a propofol continuous rate infusion (CRI) with a target-controlled infusion (TCI) in dogs. Study designRandomized prospective double-blinded clinical study. AnimalsA total of 38 healthy client-owned dogs. MethodsDogs premedicated intramuscularly with acepromazine (0.03 mg kg–1) and an opioid (pethidine 3 mg kg–1, morphine 0.2 mg kg–1 or methadone 0.2 mg kg–1) were allocated to P-CRI group (propofol 4 mg kg–1 intravenously followed by CRI at 0.2 mg kg–1 minute–1), or P-TCI group [propofol predicted plasma concentration (Cp) of 3.5 μg mL–1 for induction and maintenance of anaesthesia via TCI]. Plane of anaesthesia, heart rate, respiratory rate, invasive blood pressure, oxygen haemoglobin saturation, end-tidal carbon dioxide and body temperature were monitored by an anaesthetist blinded to the group. Numerical data were analysed by unpaired t test or Mann–Whitney U test, one-way analysis of variance and Dunnett’s post hoc test. Categorical data were analysed with Fisher’s exact test. Significance was set for p < 0.005. ResultsOverall, propofol induced a significant incidence of relative hypotension (mean arterial pressure 20% below baseline, 45%), apnoea (71%) and haemoglobin desaturation (65%) at induction of anaesthesia, with a higher incidence of hypotension and apnoea in the P-CRI than P-TCI group (68% versus 21%, p = 0.008; 84% versus 58%, p = 0.0151, respectively). Propofol Cp was significantly higher at intubation in the P-CRI than P-TCI group (4.83 versus 3.5 μg mL–1, p < 0.0001), but decreased during infusion, while Cp remained steady in the P-TCI group. Total propofol administered was similar between groups. Conclusions and clinical relevanceBoth techniques provided a smooth induction of anaesthesia but caused a high incidence of side effects. Titration of anaesthesia with TCI caused fewer fluctuations in Cp and lower risk of hypotension compared with CRI.

Location matters: Overlooked ethnic-geographic effect in China and Austria on propofol/cisatracurium sex differences among a population pharmacokinetic/pharmacodynamic (PopPK/PD) covariate analysis in men, women, and one transgender subject.

A quick literature search using "sex/gender" vs. the commonly used hypnotic propofol or neuromuscular-blocking agent cisatracurium will reveal numerous contradictory sex difference publications depending on the ethnic-geographic location of where these studies were conducted. We induced anesthesia with cisatracurium besylate (GlaxoSmithKline) 100μgkg-1 administered exactly 1minute following propofol (AstraZeneca) 2mgkg-1 . In 20male and 20 female ethnic Han-Chinese test set patients (Xi'an China), and in similar ethnic white Austrian validation set patients (Graz Austria), we quantified propofol/cisatracurium pharmacodynamic parameters namely propofol onset time, lag time, plasma concentrations (Cp ) at loss-of-behavioral response (LOBR) using bispectral index (BIS); cisatracurium onset time, lag time, and Cp at T1 % (first twitch of train-of-four) complete twitch suppression using mechanomyography (MMG). Serial arterial blood samples were collected for population pharmacokinetic (PopPK) analysis of all demographic and biological covariates (region, sex, age, weight, and height) versus volumes of distribution and clearances pharmacokinetic parameters. In Chinese women (but not in white women), propofol Cp at LOBR was 33.60% lower than men and cisatracurium Cp at T1 % complete twitch suppression was 21.49% lower than men, a clear pharmacodynamic assertion. Region and weight were significant PopPK covariates. We demonstrated that sex differences are influenced by ethnic-geographic location as only in Chinese women (but not in white women) propofol Cp at LOBR and cisatracurium Cp at T1 % complete twitch suppression were lower than in men. When defining sex differences, ethnic-geographic location should be taken into consideration as a predictive factor for optimizing propofol/cisatracurium initial loading recommended dosages.

Propofol infusions using a human target controlled infusion (TCI) pump in chimpanzees (Pan troglodytes)

Chimpanzees are genetically and physiologically similar to humans. Several pharmacokinetic models of propofol are available and target controlled infusion (TCI) of propofol is established in humans, but not in chimpanzees. The purpose of this study was to investigate if human pharmacokinetic models can accurately predict propofol plasma concentration (Cp) in chimpanzees and if it is feasible to perform TCI in chimpanzees. Ten chimpanzees were anaesthetized for regular veterinary examinations. Propofol was used as an induction or maintenance agent. Blood samples were collected from a catheter in a cephalic vein at 3–7 time points between 1 and 100 min following the propofol bolus and/or infusion in five chimpanzees, or TCI in six chimpanzees. Cp was measured using high-performance liquid chromatography. The Marsh, Schnider and Eleveld human pharmacokinetic models were used to predict Cp for each case and we examined the predictive performances of these models using the Varvel criteria Median PE and Median APE. Median PE and Median APE for Marsh, Schnider and Eleveld models were within or close to the acceptable range. A human TCI pump was successfully maintained propofol Cp during general anesthesia in six chimpanzees. Human propofol pharmacokinetic models and TCI pumps can be applied in chimpanzees.

Propofol-Bispectral Index (BIS) Electroencephalography (EEG) Pharmacokinetic-Pharmacodynamic Model in Patients With Post-Cerebral Hemorrhage Hydrocephalus.

Background. Titrating hypnotic agents for patients who suffer from a cerebral insult is a challenging task. To date there is no real gold standard to precisely quantify electroencephalography (EEG) response in a fashion that could be utilized for patients with post-cerebral hemorrhage hydrocephaly. While we must administer "as per usual" analgesics for noxious stimuli, we have to administer the hypnotic agents more "sparingly" due to lack of objective monitoring. Methods. We compared 15 adult post-cerebral hemorrhage hydrocephalus patients undergoing ventriculo-peritoneal shunt placement with 15 controls matched for gender and approximate age. We set propofol target controlled infusion estimated plasma concentrations (Cp) to gradually reach 4 µg/mL over 4 minutes. To precisely quantify post-cerebral hemorrhage mental dysfunction, we used electronically retrieved bispectral index (BIS) and propofol Cp data points to create individual inhibitory monophasic mathematical model for each patient that incorporates an independent hysteresis "lag" function. Results. In post-cerebral hemorrhage patients Cp-BIS curve, C50 (propofol concentration associated with inhibitory 50% BIS response) cutoff point was significantly shifted to the left by 39%. Whereas before infusion and at stable propofol 4 µg/mL aneurismal surgical sides ipsilateral (75 ± 13, 25 ± 9) and contralateral (73 ± 15, 27 ± 9) mean ± SD BIS values were significantly lower than ipsilateral (95 ± 3, 46 ± 12) and contralateral (94 ± 3, 46 ± 12) matched controls. Conclusions. Using BIS as surrogate marker of propofol hypnotic effect, BIS monitoring in patients with post-cerebral hemorrhage hydrocephaly showed a pattern of change and trend that was similar albeit 39% significantly lower than subjects without.

Suspected propofol infusion syndrome during normal targeted propofol concentration.

To this day, the pathophysiology and risk factors of propofol infusion syndrome (PRIS) remain unknown. Moreover, there is no widely accepted definition of PRIS, even though it is a potentially fatal condition. While many suspected cases of PRIS have been reported in both pediatric and adult populations, the actual propofol plasma concentration (Cp) has never been clarified. In this clinical report, we described the first suspected PRIS case in which the propofol Cp was measured 25min after 226min of propofol infusion (7.2µg/mL), which was 12 times higher than the predicted value (0.6µg/mL). In the presented case, we observed gradually progressive uncontrollable hypercapnia and tachycardia, followed by severe lactic acidosis during surgical anesthesia based on the target-controlled infusion of propofol. Levels of liver enzymes were slightly elevated which suggests little or no liver damage though propofol is mainly metabolized by the liver. Meanwhile, renal impairment, a common secondary feature of PRIS, occurred concomitantly when hypercapnia and metabolic acidosis were manifested. In this case, low or delayed propofol clearance might have been a triggering factor causing severe lactic acidosis.

Age progression from vicenarians (20-29year) to nonagenarians (90-99year) among a population pharmacokinetic/pharmacodynamic (PopPk-PD) covariate analysis of propofol-bispectral index (BIS) electroencephalography.

Pharmacokinetic/pharmacodynamic (PK/PD) modeling has made an enormous contribution to intravenous anesthesia. Because of their altered physiological, pharmacological and pathological aspects, titrating general anesthesia in the elderly is a challenging task. Eighty patients were consecutively enrolled divided by decades from vicenarians (20-29year) to nonagenarians (90-99year) into eight groups. Using target controlled infusion (TCI) and electroencephalographic (EEG)-derived bispectral index (BIS) we set propofol plasma concentration (Cp) to gradually reach 3.5μgmL-1 over 3.5-min. In each patient, we constructed a PK/PD model and conducted a population PK/PD (PopPK-PD) covariate analysis. Age was significant covariate for baseline BIS effect (E0), inhibitory propofol concentration at 50% BIS decline (IC50) and maximum BIS decline (Emax). First-order rate constant Ke0 of 0.47min-1 in vicenarians (20-29year) gradually increased with age-progression to 1.85min-1 in nonagenarians (90-99year). Simulation modelling showed that clinically recommended Cp of 3.5μgmL-1 for 20-29year BIS 50 should be reduced to 3.0 for 30-49year, 2.5 for 50-69year and 2.0 for 80-89year. We quantified and graded EEG-BIS age-progression among different age groups divided by decades. We demonstrated deeper BIS values with decades' age progression. Our data has important implications for propofol dosing. The practical information for physicians in their daily clinical practice is using propofol Cp of 3.5μgmL-1 might not yield BIS value of 50 in elderly patients. Our simulations showed that the recommended regimen of Cp 3.5μgmL-1 for 20-29year should be gradually decreased to 2.0μgmL-1 for 80-89year. European Community Clinical Trials Database EudraCT (http://eudract.emea.eu) initial trial registration number: 2011-002847-81, and subsequently registered at www.clinicaltrials.gov; trial registration number: NCT02585284. Xijing Hospital of Fourth Military Medical University ethics committee approval number 20110707-4.

Propofol post-conditioning after temporary clipping reverses oxidative stress in aneurysm surgery

Purpose: Animal studies have demonstrated that propofol post-conditioning produces long-term neuroprotection in focal cerebral ischemia–reperfusion injury. However, whether propofol post-conditioning provides neuroprotection in human beings has never been explored. The aim of this study was to evaluate the role of propofol post-conditioning on oxidative stress and post-operative cognitive function following aneurysm clipping.Materials and Methods: Sixty patients undergoing intracranial aneurysm clipping were randomized into a propofol post-conditioning group or a sevoflurane group. Sevoflurane (0.5–2%) was used for maintenance anesthesia in both groups. In the propofol post-conditioning group, the inhaled concentration of sevoflurane was reduced after temporary clip removal to keep the bispectral index (BIS) value between 40 and 60, and propofol (Cp 1.2 µg/mL) was subsequently started. Blood samples were drawn at six time points: before induction, immediately after clip removal, at the end of the operation, 24-h post-surgery, 3 days post-surgery, and 7 days post-surgery. Oxidative stress and cognitive function were measured.Results: Between the conclusion of the operation to 7 days after surgery, propofol post-conditioning decreased the serum concentration of •OH and 8-isoprostane and increased γ-tocopherol and SOD. Reduced micronuclei and nucleoplasmic bridges were observed in the propofol post-conditioning group. Mini-Mental State Examination (MMSE) and Montreal Cognitive Assessment (MoCA) scores were improved by propofol post-conditioning compared to the group that received no propofol.Conclusions: Together, our data suggest that propofol post-conditioning (Cp 1.2 µg/mL) may protect the brain from oxidative stress injury up to 7 days post-surgery after temporary parent artery clipping. Furthermore, the neuroprotection induced by propofol post-conditioning may contribute to improvement in cognitive function.Trial registration: ClinicalTrials.gov identifier: NCT02691416.

Propofol-fentanyl interaction in Beagles - Apnea, response to mechanical ventilation, endotracheal tube, and tetanic stimulation

The objective of this study was to characterize the propofol-fentanyl interaction in Beagles for four pharmacodynamic endpoints: apnea, response to mechanical ventilation, endotracheal tube, and tetanic stimulation.After anesthesia was induced with varying combinations of propofol and fentanyl, the pharmacodynamic endpoints were assessed in intubated dogs (n=6) using the cross-over design. Effective concentrations of propofol plasma concentration (Cp) and fentanyl Cp were assessed using additive, reduced Greco, Minto, and hierarchical interaction models.The interaction was best described as synergistic by the hierarchical model. A 1ng/mL fentanyl Cp reduced the effective propofol Cp to half or less of that without fentanyl for all endpoints. An additional increment of fentanyl Cp to 5ng/mL or higher hardly reduced effective propofol Cp for all endpoints except response to tetanic stimulation. Additionally, the effective propofol Cp in 50% dogs for response to tetanic stimulation (15% increase of heart rate) was lower than that for the other endpoints at fentanyl Cp >7ng/mL. Peripheral oxygen saturation decreased below 90% after extubation in five treatments in which fentanyl Cps were ≥5ng/mL.Propofol and fentanyl interacted synergistically. To avoid patient-ventilator dyssynchrony and hypoxemia after extubation, fentanyl Cp at 1–5ng/mL may be appropriate in intubated dogs. When a dog responds to mechanical ventilation or endotracheal tube at a high fentanyl Cp >5ng/mL under propofol anesthesia even if the dog tolerate to tetanic stimulation, it may be necessary to increase propofol Cp to eliminate the responses because an additional fentanyl may be little impact.

Pharmacodynamic analysis of target-controlled infusion of propofol in patients with hepatic insufficiency.

The effect of liver dysfunction on target-controlled infusion (TCI) of propofol remains poorly documented. The pharmacodynamic performance of propofol TCI was evaluated in a cohort of Chinese patients with hepatic insufficiency. Fifty-three patients with hepatic insufficiency were enrolled in the current prospective, observational study. Anesthesia was induced with propofol via TCI to a plasma concentration of 3 µg/ml. Following loss of consciousness (LOC), fentanyl and cisatracurium were administered. Pharmacodynamic parameters were recorded during TCI, including time to LOC, bispectral index (BIS), heart rate (HR) and blood pressure. Patients were divided into two groups based on model of end stage liver disease (MELD) score: Those with a MELD score of ≤9 and those with a MELD score of ≥10. BIS, mean arterial pressure and HR were demonstrated to vary according to time, but were not affected by liver dysfunction. Hypotension was prominent in patients with a MELD score of ≥10 30 min after induction. The proportion of bradycardia and hypotension at the other time points was not significantly different between MELD scores of ≤9 and ≥10. Notably, no bradycardia was observed in MELD of ≥10. Thus, bradycardia and hypotension was observed in patients with hepatic insufficiency over time, although patients with different severities of hepatic insufficiency did not present with different depths of anesthesia. TCI of propofol to 3 µg/ml may be not suitable for patients with hepatic insufficiency, particularly those with severe liver dysfunction. Predictive concentrations (Cp) of TCI propofol requires further investigation and adjustment in patients with hepatic insufficiency (trial registration no. ChiCTR-OCH-12002255).

Efficacy of different doses of dexmedetomidine combined with propofol for drug-induced sleep endoscopy in patients with snoring

Objective To evaluate the efficacy of different doses of dexmedetomidine combined with propofol for drug-induced sleep endoscopy(DISE)in the patients with snoring. Methods Sixty patients with snoring, aged 24-62 yr, with body mass index of 24-37 kg/m2, of American Society of Anesthesiologists physical status Ⅰ or Ⅱ, scheduled for elective DISE, were randomly divided into either group Ⅰor groupⅡ, with 30 patients in each group.In Ⅰ and Ⅱ groups, dexmedetomidine was infused over 10 min in a loading dose of 0.4 and 0.8 μg/kg, respectively, followed by an infusion of 0.4 μg·kg-1·h-1.At 15 min of dexmedetomidine infusion, propofol was given by target-controlled infusion with the initial target plasma concentration(Cp)of 1.0 μg/ml.At 2 min after the target effect-site and plasma concentrations were balanced, the Cp of propofol was increased/decreased by 0.2 μg/ml to maintain the Cp of propofol stable during DISE.Bispectral index(BIS)value was recorded before anesthesia(T1), at 10 and 15 min of dexmedetomidine infusion(T2, 3), at 2 min after the target effect-site and plasma concentrations were balanced(T4), at the beginning of DISE(T5), when the fiberoptic laryngoscope was placed at the site of oropharynx(T6), at the end of DISE(T7), at emergence(T8), and while discharge from the examination room(T9). Richmond Agitation Sedation Scale(RASS)scores were recorded at T1-4.Sleep was recorded within 15 min of dexmedetomidine infusion.The emergence time, discharge time, and anesthetics-related adverse events were recorded. Results All the patients completed DISE successfully.BIS values were maintained at 75-90, and RASS scores ≤ 4 during dexmedetomidine infusion.BIS values were maintained at 65-75 during DISE.Compared with groupⅠ, BIS values were significantly decreased at T4, and RASS scores were significantly increased at T2-4, the sleep rate was significantly increased within 15 min of dexmedetomidine infusion, the Cp of propofol was significantly decreased during DISE, the emergence time was significantly prolonged(P 0.05). Conclusion Dexmedetomidine infused at 0.4 μg·kg-1·h-1 after infusion of a loading dose of 0.8 μg/kg combined with propofol provides better efficacy for DISE in the patients with snoring. Key words: Dexmedetomidine; Propofol; Snoring; Endoscopy; Sleep

Neuromuscular effects of cisatracurium besylate in obese patients

To explore the neuromuscular effects of cisatracurium besylate in morbidly obese patients when dosed according to real body weight under total intravenous anesthesia with propofol. Thirty-six ASA I-II patients aged 18-65 years scheduled for elective procedures at our hospital during July 2012 to December 2012 were allocated into 2 groups according to body mass index (normal weight: body mass index: <24, overweight: body mass index >28). Anesthesia was induced with target-controlled infusion of propofol (Cp 3 µg/ml) and remifentanil (Ce 3-5 ng/ml). A bolus of cisatracurium 0.2 mg/kg was administered intravenously over 5-10 s as soon as a patient lost consciousness. Neuromuscular block was monitored with TOF-Watch SX (Oaganon, the Netherlands). Single stimulation (0.1 Hz) was applied to ulnar nerve at wrist. The maximal degree of neuromuscular block, onset time, clinical duration and recovery index were recorded. They were intubated and mechanically ventilated when neuromuscular block reached the maximal degree. The intubation condition was evaluated. The average onset time was (164 ± 25) s in obese group versus (201 ± 48) s in normal weight group. And there was significant difference between groups (t = 2.83, P < 0.05) . The clinical duration was (68.4 ± 9.6) min in obese group versus (62.0 ± 6.5) min in normal weight group. And there was significant difference between groups (t = 2.33, P < 0.05). The recovery index was (15.6 ± 4.7) min in obese group versus (10.8 ± 4.2) min in normal weight group. And there was significant difference between groups (t = 3.03, P < 0.05) . Also 75% recovery time was (83.9 ± 11.5) min in obese group versus (73.0 ± 9.2) min in normal weight group. And there was significant difference between groups (t = 2.94, P < 0.05). But no differences existed in intubation conditions. When dosed according to real body weight, onset time of cisatracurium is shorter while clinical duration and recovery index are prolonged in morbidly obese patients compared with normal weight counterparts.

Effects of propofol and fentanil compounded different doses of dexmedetomidine on hymodynamics and intraoperative somatosensory and motor evoked potentials monitoring of senile patient

Objective To evaluate the effects of different doses of dexmedetomidine compounded propofol and fentanil on hymodynamics and intraoperative somatosensory evoked potentials (SEPs) and motor evoked potentials (MEPs) monitoring on the senile people.Methods Forty-five patients undergoing selected anterior spinal fusion surgery were randomly divided into three groups by the dose of dexmedetomidine: group C (normal saline,NS); group D1 (dexmedetomidine injected by 0.3 μg·kg-1·h-1);group D2(dexmedetomidine injected by 0.8 μg·kg-1·h-1).The induction of all patients in three groups:midazolam 2 mg-3 mg,propofol Cp 1.5 mg/L (Marsh model),fentanil 1.5 μg/kg-2 μg/kg.When the patient's consciousness disappeared,a LMA was intubated and mechanical ventilation was made.In group D1 and group D2,dexmedetomidine (0.5 μg/kg over 10 min) was administered and then followed by an infusion of 0.3 μg·kg-1 ·h-1 or 0.8 μg ·kg-1 ·h-1 until the end of surgery.In group C,the same dose of NS instead of dexmedetomidine was administered.Anesthesia was maintained by target controlled injection of propofol.Bispectral index (BIS) were kept in the range of 45-55 by adjusting the concentration of propofol.Muscle relaxant wasn't be used in whole operation.SEPs and MEPs were monitored by a specialist during the operation.Results Heart rate were lower in group D1 and D2 than group C,but mean arterial pressure (MAP) were no different in three groups.The latency and the amplitude of SEPs P15-N20 were also no different in three groups (P＞0.05).Three patients's amplitudes of MEPs were disappeared in different degrees among the group D2.The positive rate is 3/15.There was a significant difference from the cases of group D1 (0/14) and C (0/14).After dexmedetomidine was stopped about 20 min-30 min,the amplitudes of MEPs recoveried in all the three patients.Conclusions In scnile paticnts,dexmedetomidine possibly prolonged analepsia time and decreased heart rate.Dexmedetomidine does not significantly influence the SEPs,but higher dose of dexmedetomidine depressed MEPs. Key words: Anesthesia, general; Senile; Anesthetics, intravenous; Evoked potentials; Medetomidine; Propofol

Effects of UDP glucuronosyltransferase 1A9 I399 C ＞ T single nucleotide polymorphism on postoperative analgesia with propofol in patients undergoing breast surgery

Objective To investigate the effects of UDP glucuronosyhransferase （UGT） 1A9 I399 C 〉 T single nucleotide polymorphism on postoperative sedation with propofol in patients undergoing breast surgery. Methods One hundred and fifty-two ASA I or Ⅱ female patients, aged 20-50 yr, weighing 50-70 kg, scheduled for elective benign breast tumor excision under general anesthesia, were enrolled in this study. The polymorphic sites of the UGT1A9 I399 C 〉 T allele were analyzed by polymerase chain reactionestriction fragment length polymorphism. The patients were assigned to one of 3 groups according to their genotypes： wild homozygote （C/C） group, mutation heterozygote （C/T） group and mutation homozygote （T/T） group. During induction and maintenance of anesthesia, propofol was given by target-controlled infusion with the plasma concentration （Cp） of 3 tLg/ml. Blood samples were taken at 60 min after target-controlled infusion of propofol was started for determination of the Cp of propofol using high-performance liquid chromatography. The time when OAAS was 4 after stopping the infusion of propofol was recorded and the BIS value and effect-site concentration of propofol were also recorded at this time. The time when BIS value was 80 was recorded and the effect-site concentration of propofol was also recorded at this time. Results Genotyping analysis revealed that genotype distribution of UGT1 A9 1399 C 〉 T polymorphism wasC/C 24 cases, C/T 96 cases and T/T 32 cases. The T allele frequency was 53 %. The C allele frequency was 47.4%. There was no significant difference in the Cp of propofol, time when OAAS was 4, BIS value and effectsite concentration of propofol when OAAS was d, time when BIS value was 80 and effect-site concentration of propotbl when BIS value was 80 among the three groups （ P 〉 0.05）. Conclusion UGT1 A9 I399C 〉 T single nucleotide polymorphism is not the＇ genetic factor contributing to the individual variation in the patient s response to postoperative analgesia with propofol in patients undergoing breast surgery. Key words: Propofol ; Conscious sedation ; Glucosyltransferases ; Polymorphism, single nucleotide

Evaluation of the predictive performance of a pharmacokinetic model for propofol in Japanese macaques (Macaca fuscata fuscata)

Propofol is a short-acting intravenous anesthetic used for induction/maintenance anesthesia. The objective of this study was to assess a population pharmacokinetic (PPK) model for Japanese macaques during a step-down infusion of propofol. Five male Japanese macaques were immobilized with ketamine (10 mg/kg) and atropine (0.02 mg/kg). A bolus dose of propofol (5 mg/kg) was administrated intravenously (360 mg/kg/h) followed by step-down infusion at 40 mg/kg/h for 10 min, 20 mg/kg/h for 10 min, and then 15 mg/kg/h for 100 min. Venous blood samples were repeatedly collected following the administration. The plasma concentration of propofol (Cp) was measured by high-speed LC-FL. PPK analyses were performed using NONMEM VII. Median absolute prediction error and median prediction error (MDPE), the indices of prediction inaccuracy and bias, respectively, were calculated, and PE - individual MDPE vs. time was depicted to show the variability of prediction errors. In addition, we developed another population pharmacokinetic model using previous and current datasets. The previous PK model achieved stable prediction of propofol Cp throughout the study period, although it underestimates Cp. The step-down infusion regimen described in this study would be feasible in macaques during noninvasive procedures.

Difference in rocuronium-induced muscle relaxation between patients of Buyi and Han nationality

Objective To determine whether there is any difference in rocuronium-induced muscle relaxation between patients of Buyi and Han nationality.Methods Sixty ASA Ⅰ or Ⅱ patients of both sexes aged 20-55 yr,with body mass index of 20-25 kg/m2,undergoing laparoscopic or arthroscopic surgery under general anesthesia,were divided into 2 groups ( n =30 each):Han group (group H) and Buyi group (group B).Anesthesia was induced with midazolam,fentanyl and TCI of propofol (Cp=2-3 μg/ml).Tracheal intubation was facilitated with rocuronium 0.6 mg/kg.The patients were mechanically ventilated.PETCO2 was maintained at 30-35 mm Hg.Neuro-muscular (N-M) function was monitored by accelerography.N-M block was assessed by single stimulation of ulna nerve after loss of consciousness.The onset time,maximal N-M block time,clinical muscle relaxation time (from injection d rocuronium to 25％ recovery),75％ recovery time (from injection of rocuronium to 75％ recovery) and recovery index were recorded.The plasma concentration of albumin and α1-acid glycoprotein were measured by ELISA and biochemical analysis respectively.Results The onset time was significantly longer and plasma α1-acid glycoprotein concentration lower in group B than in group H.There was no significant difference in maximal N-M block time,clinical muscle relaxation time,75％ recovery time,recovery index and plasma albumin concentration between the 2 groups.Conclusion The onset time of rocuronium-induced N-M block is longer in patients of Buyi nationality as compared with patients of Han nationality.Lower plasma α1 -acid.glycoprotein concentration may be involved in the underlying mechanism. Key words: Androstanols; Ethnic groups; Han nationality; Neuromuscular blockade

Effect of ovarian cycle on sedative effect of propofol

Objective To investigate the effect of ovarian cycle on the sedative effect of propofol in patients. Methods Forty ASA Ⅰ or Ⅱ patients, aged 20-40 yr, with body mass index 20-25 kg/m2 , scheduled for elective gynecologic laparoscopic surgery, were divided into 2 groups according to the progesterone level ( n = 20 each): follicular phase group (group F, serum progesterone concentration 0.31-1.52 ng/ml) and luteal phase group (group L, serum progesterone concentration 5.16-18.56 ng/ml). Anesthesia was induced with target-controlled infusion (TCI) of propofol and iv injection of fentanyl and cisatracurium. The initial target plasma concentration (Cp) of propofol was set at 2 μg/ml, after the Cp reached the predetermined level, the Cp increased by 0.5 μg/ml every 30 s until the patients lost consciousness and BIS value was decreased to 50. The BIS value and Cp of propofol was recorded when the patients lost consciousness. The Cp of propofol was also recorded when BIS value was decreased to 50. The patients were tracheal intubated and mechanically ventilated. Anesthesia was maintained with TCI of propofol combined with remifentanil. BIS value was maintained at 45-55 by adjusting the Cp of propofol. Results The Cps of propofol were significantly higher when the patients lost consciousness and when BIS value was decreased to 50 in group F than in group L ( P ＜ 0.05 or 0.01) . There was no significant difference in BIS value when the patients lost consciousness between the two groups (P ＞ 0.05). Conclusion Ovarian cycle can affect the sedative effect of propofol in patients, which shows that the sedative effect during the follicular phase is lower than that during the luteal phase. Key words: Menstrual cycle; Propofol; Conscious sedation