Target-controlled Infusion Of Propofol Research Articles

Photoplethysmography Response to Laryngeal Mask Airway Insertion during Propofol-Remifentanil Anethesia.

The present study was aimed to evaluate the abilities of photoplethysmography (PPG)-derived parameters, including sample entropy of PPG (SampEn), amplitude of PPG (PPGA), pulse beat interval (PBI) and diastolic interval (DI) extracted by nonlinear or linear methods, to monitor the balance between nociception and antinociception. 26 ASA I or II patients were randomized into one of the three groups to receive a remifentanil effect-compartment target controlled infusion (Ceremi) of 1, 3 and 5 ng/ml and an effect-compartment target controlled propofol infusion (Ceprop) to keep the state entropy (SE) at 50 (40~60). Laryngeal mask airway (LMA) insertion was applied as a noxious stimulus. The percentage of change in SampEn (△SampEn, AUC=0.896), PBI (△PBI, AUC=0.896) and DI (ΔDI, AUC=0.972), but not in PPGA (△PPGA, AUC=0.667), were statistically excellent in discriminating low Ceremi (1 ng/ml) from higher Ceremi (3 and 5 ng/ml). Additionally, the prediction probabilities (Pk) values of △SampEn, ΔPBI and ΔDI were high as well with 0.795, 0.754 and 0.813 for discriminating Ceremi. These results demonstrated that nonlinear and linear parameters of SampEn, PBI and DI had strong dependency on Ceremi in response to LMA insertion and could provide nociceptive information during propofol-remifentanil anesthesia. This indicated that PPG-derived parameters were potential to develop the clinical assessment of nociception-antinociception balance under general anesthesia.

Phase lag entropy as a hypnotic depth indicator during propofol sedation.

Phase lag entropy, an electro-encephalography-based hypnotic depth indicator, calculates diversity in temporal patterns of phase relationship. We compared the performance of phase lag entropy with the bispectral index™ in 30 patients scheduled for elective surgery. We initiated a target-controlled infusion of propofol using the Schnider model, and assessed sedation levels using the Modified Observer's Assessment of Alertness/Sedation scale every 30s with each stepwise increase in the effect-site propofol concentration. Phase lag entropy and bispectral index values were recorded. The correlation coefficient and prediction probability between phase lag entropy or bispectral index and the sedation level or effect-site propofol concentration were analysed. We calculated baseline variabilities of phase lag entropy and bispectral index. In addition, we applied a non-linear mixed-effects model to obtain the pharmacodynamic relationships among the effect-site propofol concentration, phase lag entropy or bispectral index and sedation level. As sedation increased, phase lag entropy and bispectral index both decreased. The prediction probability values of phase lag entropy and bispectral index for sedation levels were 0.697 and 0.700 (p=0.261) and for the effect-site concentration of propofol were 0.646 and 0.630 (p=0.091), respectively. Baseline variability in phase lag entropy and bispectral index was 3.3 and 5.7, respectively. The predicted propofol concentrations, using the Schnider pharmacokinetic model, producing a 50% probability of moderate and deep sedation were 1.96 and 3.01μg.ml-1 , respectively. Phase lag entropy was found to be useful as a hypnotic depth indicator in patients receiving propofol sedation.

Effect of remifentanil combined with propofol on anesthesia in gynecological laparoscopic surgery

Objective To study the effect of remifentanil combined with propofol target-controlled infusion on anesthesia of gynecological laparoscopic surgery. Methods From August 2016 to August 2018, 132 patients who needed to undergo gynecological laparoscopy in the Maternal and Child Health Care Hospital of Qujing were selected.The patients were randomly divided into two groups according to the principle of simple randomization, with 66 cases in each group.The observation group was given.remifentanil combined with propofol administered by target-controlled infusion for anesthesia.The control group were given fentanyl intravenous anesthesia.The clinical efficacy of the two groups was observed. Results The onset time of anesthesia[(1.3±0.3)min], awake time[(5.2±1.5)min], anesthesia recovery time[(19.6±5.3)min]and analgesic time[(23.6±3.5)min]in the observation group were all shorter than those in the control group[(3.1±0.6)min, (5.0±3.5)min, (4.06±4.8)min, (48.3±4.4)min](t=12.742, 15.102, 11.265, 12.354, all P<0.0). At 1 min after hemodynamic intubation, 10 min after pneumoperitoneum, 30 min after operation and 30min after operation, the heart rate, systolic blood pressure (SBP) and diastolic blood pressure (DBP) in the observation group were (82.38±7.45)times/min, (85.65±8.54)times/min, (77.58±8.65)times/min, (80.12±7.77)times/min, SBP: (136.25±20.14)mmHg, (140.36±18.02)mmHg, (129.14±15.24)mmHg, (131.25±16.19)mmHg, DBP: (986.45±11.02)mmHg, (86.59±10.11)mmHg, (80.17±8.29)mmHg, (82.52±8.17)mmHg, which were better than those in the control group[herat rate: (88.14±10.01)times/min, (95.36±8.48)times/min, (86.58±7.33)times/min, (87.48±8.47)times/min; SBP: (140.28±21.57)mmHg, (144.59±21.35)mmHg, (137.33±18.47)mmHg, (136.25±18.47)mmHg; DBP: (90.0±10.14)mmHg, (90.25±11.24)mmHg, (84.25±10.14)mmHg, (82.55±8.84)mmHg](F=1.320, 1.245, 1.365, all P<0.05). Conclusion Remifentanil combined with propofol target controlled infusion for patients undergoing gynecological laparoscopic surgery is helpful to enhance the anesthetic effect, and has a short pharmacodynamic effect, which is conducive to ensuring the quality of surgery.Therefore, it is worthy of popularizing in clinical practice. Key words: remifentanil; Propofol; Gynecological surgical procedures; Laparoscopy; Anesthesia

A pharmacokinetic model optimized by covariates for propofol target-controlled infusion in dogs

ObjectiveTo develop a population pharmacokinetic model for propofol target-controlled infusion (TCI) in dogs and to evaluate its performance for use in the clinical setting. Study designProspective clinical study. AnimalsA group of 40 client-owned dogs undergoing general anaesthesia for magnetic resonance imaging. MethodsPropofol was administered to 26 premedicated dogs and arterial blood samples were collected during the infusion and over 240 minutes after terminating the infusion. Propofol concentrations were measured by high-performance liquid chromatography. A population pharmacokinetic analysis was performed using a nonlinear mixed-effects modelling approach, allowing inter- and intra-individual variability estimation and quantitative evaluation of the influence of the following covariates: weight, body condition score, age, size-related age (Age_size), sex, premedication type, size and contrast agent administration. A final model was obtained using a stepwise approach in which individual covariate effects on each pharmacokinetic variable were incorporated. The performance of the developed TCI model was subsequently evaluated while inducing and maintaining anaesthesia in 14 premedicated dogs and assessed by comparing predicted and measured concentrations at specific time points. ResultsPropofol pharmacokinetics was best described by a three-compartment model. Weight, Age_size, premedication and sex showed significant pharmacokinetic effects. Addition of the significant covariate/variable associations to the final model resulted in a reduction of the objective function value from 285.53 to –22.34. The median values of prediction error and absolute performance error were 3.1% and 28.4%, respectively. Induction targets between 4.0 and 6.5 μg mL–1 allowed intubation within 5.0 ± 0.9 minutes. Anaesthesia was achieved with targets between 3.0 and 6.5 μg mL–1. Mean time to extubation was 9.7 ± 2.6 minutes. All dogs recovered smoothly and without complications. Conclusions and clinical relevanceOverall predictive performance of the pharmacokinetic model-driven infusion developed was clinically acceptable for administering propofol to dogs in routine anaesthesia.

Comparison of Propofol Target-Controlled Infusion Anesthesia and Bolus Injection in Electroconvulsive Therapy

Comparison of Propofol Target-Controlled Infusion Anesthesia and Bolus Injection in Electroconvulsive Therapy

A study protocol for a feasibility study: Propofol Target-Controlled Infusion in Emergency Department Sedation (ProTEDS)\u2014a multi-centre feasibility study protocol

BackgroundProcedural sedation is a core skill of the emergency physician. Bolus administration of propofol is widely utilised in UK emergency departments to provide procedural sedation. Bolus administration of propofol, titrated to an endpoint of sedation, has a rapid effect but can easily result in apnoea and loss of airway patency. The use of a target-controlled infusion of propofol allows for controlled titration to an effect site concentration and may reduce the rate of adverse incidents. Target-controlled infusion of propofol is not currently used in emergency departments.The primary aim of this feasibility study is to ensure that propofol target-controlled infusion (TCI) is acceptable to the patient and that recruitment rates are adequate to power a randomised controlled trial comparing propofol target-controlled infusion versus bolus administration.MethodsThis study will recruit in four emergency departments in Scotland, UK. Patients aged 18–65 years with anterior shoulder dislocation, weighing ≥ 50 kg and fasted ≥ 90 min, will be screened. Recruited patients will undergo emergency reduction of a dislocated shoulder facilitated by procedural sedation utilising TCI of propofol.The widespread adoption of TCI propofol by emergency departments will require evidence that it is safe, potentially effective, patient centred and a timely method of providing procedural sedation. The primary endpoint will be acceptability measured by patient satisfaction. The secondary endpoints will include incidence and severity of adverse events, number of shoulder reduction attempts, nursing opinion of patient experience, patient’s reported pain score and time from commencement of TCI propofol sedation to desired sedation level.The study will be open for recruitment from April 2017 to December 2018.DiscussionIf the study demonstrates patient acceptability with adequate recruitment, we will be in a position to determine the feasibility of progression to a randomised controlled clinical trial of TCI compared to bolus administration of propofol.Trial registrationClinicalTrials.gov Identifier: NCT03442803. Registered retrospectively on 22 February 2018.

EEG profiles during general anesthesia in children: A comparative study between sevoflurane and propofol.

In this prospective study, we describe the electroencephalographic (EEG) profiles in children anesthetized with sevoflurane or propofol. Seventy-three subjects (11years, range 5-18) were included and randomly assigned to two groups according to the anesthetic agent. Anesthesia was performed by target-controlled infusion of propofol (group P) or by sevoflurane inhalation (group S). Steady-state periods were performed at a fixed randomized concentration between 2, 3, 4, 5, and 6μg.ml-1 of propofol in group P and between 1, 2, 3, 4, and 5% of sevoflurane in group S. Remifentanil was continuously administered throughout the study. Clinical data, Bispectral Index (BIS), and raw EEG were continuously recorded. The relationship between BIS and anesthetic concentrations was studied using nonlinear regression. For all steady-state periods, EEG traces were reviewed to assess the presence of epileptoid signs, and spectral analysis of raw EEG was performed. Under propofol, BIS decreased monotonically and EEG slowed down as concentrations increased from 2 to 6μg.ml-1 . Under sevoflurane, BIS decreased from 0% to 4% and paradoxically rose from 4% to 5% of expired concentration: this increase in BIS was associated with the occurrence of fast oscillations and epileptoid signs on the EEG trace. Propofol was associated with more delta waves and burst suppression periods compared to sevoflurane. Under deep anesthesia, the BIS and electroencephalographic profiles differ between propofol and sevoflurane. For high concentrations of sevoflurane, an elevated BIS value may be interpreted as a sign of epileptoid patterns or EEG fast oscillations rather than an insufficient depth of hypnosis.

Measuring the accuracy of propofol target-controlled infusion (TCI) before and after surgery with major blood loss.

Target-controlled infusion (TCI) is based on pharmacokinetic models designed to achieve a desired drug level in the blood. TCI's predictive accuracy of plasma propofol levels at the end of surgery with major blood loss has not been well established. This prospective observational study included adult patients (BMI 20-35kg/m2) undergoing surgery with expected blood loss ≥ 1500mL. The study was conducted with the Schnider TCI propofol model (Alaris PK Infusion Pump, CareFusion, Switzerland). Propofol levels were assessed in steady-state at the end of anaesthesia induction (Tinitial) and before the end of surgery (Tfinal). Predicted propofol levels (CTCI) were compared to measured levels (Cblood). Twenty-one patients were included. The median estimated blood loss was 1600mL (IQR 1000-2300), and the median fluid balance at Tfinal was + 3200mL (IQR 2320-4715). Heart rate, mean arterial blood pressure, and blood lactate did not differ significantly between Tinitial and Tfinal. The median bispectral index (0-100) was 50 (IQR 42-54) and 49 (IQR 42-56) at the two respective time points. At Tinitial, median CTCI was 2.2µmol/L (IQR 2-2.45) and Cblood was 2.0µmol/L (bias 0.3µmol/L, limits of agreement - 1.1 to 1.3, p = 0.33). CTCI and Cblood at Tfinal were 2.0µmol/L (IQR 1.6-2.2) and 1µmol/L (IQR 0.8-1.4), respectively (bias 0.6µmol/L, limits of agreement - 0.89 to 1.4, p < 0.0001). Propofol TCI allows clinically unproblematic conduct of general anaesthesia. In cases of major blood loss, the probability of propofol TCI overestimating plasma levels increases.Trial registration German Clinical Trials Register (DRKS; DRKS00009312).

Propofol TCI Reductions Do Not Attenuate Significant Falls in Cardiac Output Associated With Anesthesia Induction and Knee-Chest Positioning in Spinal Surgery.

Induction of anesthesia and the knee-chest position are associated with hemodynamic changes that may impact patient outcomes. The aim of this study was to assess whether planned reductions in target-controlled infusion propofol concentrations attenuate the hemodynamic changes associated with anesthesia induction and knee-chest position. A total of 20 patients scheduled for elective lumbar spinal surgery in the knee-chest position were included. In addition to standard anesthesia monitoring, bispectral index and noninvasive cardiac output (CO) monitoring were undertaken. The study was carried out in 2 parts. In phase 1, target-controlled infusion propofol anesthesia was adjusted to maintain BIS 40 to 60. In phase 2, there were 2 planned reductions in propofol target concentration: (1) immediately after loss of consciousness-reduction calculated using a predefined formula, and (2) before positioning-reduction equal to the average percentage decrease in CO after knee-chest position in phase 1. Changes from baseline in CO and other hemodynamic variables following induction of anesthesia and knee-chest positioning were compared. Induction of anesthesia led to decreases of 25.6% and 19.8% in CO from baseline in phases 1 and 2, respectively (P<0.01). Knee-chest positioning resulted in a further decrease such that the total in CO reduction from baseline to 10 minutes after positioning was 38.4% and 46.9% in phases 1 and 2, respectively (P<0.01). There was no difference in CO changes between phases 1 and 2, despite the planned reductions in propofol during phase 2. There was no significant correlation between changes in CO and mean arterial pressure. Planned reductions in propofol concentration do not attenuate anesthesia induction and knee-chest position-related decreases in CO. The knee-chest position is an independent risk factor for decrease in CO. Minimally invasive CO monitors may aid in the detection of clinically relevant hemodynamic changes and guide management in anesthetized patients in the knee-chest position.

A follow-up survey of total intravenous anesthesia usage in children in the U.K. and Ireland.

Total intravenous anesthesia usage in children remains relatively unpopular in the UK and Ireland. A postal survey by Hill et al in 2008 indicated that only 26% of Consultants used a propofol infusion at least once a month. Following an increase in teaching and training opportunities in pediatric total intravenous anesthesia in the UK, we repeated the survey among Consultant members of Association of Paediatric Anaesthetists of Great Britain and Ireland and Society for Intravenous Anaesthesia, to see if this had affected total intravenous anesthesia usage in children and how practice may have changed. We used an anonymous online survey sent to Association of Paediatric Anaesthetists of Great Britain and Ireland and Society for Intravenous Anaesthesia members. A total of 291 responses were analyzed. Total intravenous anesthesia was the default method of anesthesia in 8% of respondents and a further 46% used total intravenous anesthesia at least monthly. Overall total intravenous anesthesia usage had increased in the past year in 53%. The main indications were malignant hyperthermia susceptibility, and postoperative nausea and vomiting. Ear/nose/throat surgery was the most popular surgical specialty. The main reasons for not using total intravenous anesthesia were that it was too "fiddly" and lack of confidence in the user. Most respondents used propofol in combination with remifentanil. Over 80% used propofol target-controlled infusion. The potential for propofol-related infusion syndrome concerned many, with 74% limiting infusion duration as a result. Bispectral Index was not used routinely by the majority of anesthetists. Even though most anesthetists did not use total intravenous anesthesia routinely, 98% felt they would be confident to anesthetize an malignant hyperpyrexia-positive patient using the technique. This survey has shown that although total intravenous anesthesia is not the default anesthetic technique for most anesthetists, overall usage in children has more than doubled in the past 10years, with many happy to use it in a wide variety of patients and procedures.

Pharmacodynamic Analysis of the Influence of Propofol on Left Ventricular Long-Axis Systolic Performance in Cardiac Surgical Patients.

BackgroundPropofol induced a decline in the left ventricular (LV) systolic performance in non-cardiac surgery. We tested the hypothesis that propofol decreased the LV contractile function by dose dependent manner in cardiac surgery patients.MethodsAnesthesia was maintained with target-controlled infusions of propofol and remifentanil in cardiac surgery patients. With a fixed effect-site concentration (Ce) of remifentanil (20 ng/mL) after sternotomy, the Ce of propofol was adjusted to maintain a Bispectral index of 40–60 (Ce1). Mitral annular Doppler tissue image tracings and other echocardiographic variables, including end-diastolic and end-systolic volumes, stroke volume, and mitral inflow pulse wave Doppler profile at Ce1, were recorded using transesophageal echocardiography. Echocardiographic recordings were repeated after the Ce-values of propofol were doubled and tripled at 10-minute intervals (defined as Ce2 and Ce3, respectively). Serial changes in echocardiographic variables for each Ce of propofol were assessed using generalized linear mixed effect modeling. The pharmacodynamic relationship between the Ce of propofol and peak systolic mitral annular velocity (Sm) was analyzed by logistic regression using non-linear mixed effect modeling (NONMEM).ResultsMeans of Ce1, Ce2, and Ce3 were 0.8, 1.6, and 2.4 μg/mL, respectively, and their means of Sm (95% confidence interval) were 9.7 (9.3–10.2), 8.7 (8.2–9.1), and 7.5 cm/sec (7.0–8.0), respectively (P < 0.01). Ce values of propofol and Sm showed a significant inter-correlation and predictability (intercept, 10.8; slope–1.0 in generalized mixed linear modeling; P < 0.01). Ce values producing 10% and 20% decline of Sm with 50%-probability were 1.4 and 2.1 μg/mL, respectively.ConclusionPropofol reduces LV systolic long-axis performance in a dose-dependent manner.Trial RegistrationClinicalTrials.gov Identifier: NCT01826149

A New Pharmacokinetic Model of Propofol for Japanese Patients

Target-controlled infusion (TCI) of propofol is used for general anesthesia. However, the only pharmacokinetic parameter commercially used for Japanese patients is weight, and pharmacokinetic models are based on European physical attributes. Drug metabolism also differs in races. This study aimed to identify optimal continuous doses of propofol for Japanese patients and to create a simulated pharmacokinetic (PK) model. Thirty Japanese patients were enrolled. Patients received a constant infusion of 9 mg/kg/h of propofol. Arterial blood samples were collected and the time course of plasma propofol concentrations was modeled using the nonlinear mixed effects model (NONMEM) three-compartmental PK model. We validated the model by intravenously injecting 10 patients with a TCI driver system programmed with the NONMEM model. Our model’s performance was evaluated using the median prediction error (MDPE), median absolute prediction error (MDAPE), and Wobble. We analyzed 320 blood samples for model building and 160 samples for validating our new model. The calculated parameters for the three-compartmental PK model were volume [V1, 3.58; V2, 13.0 + 0.49 × (Age—64); and V3, 186] and elimination clearance [CL1, 0.77 + (WT—54) × 0.04 + (HT—158) × 0.03; CL2, 0.89 + 0.12 × (Age—64); and CL3, 0.98 × exp ((Age—64)/10)]. The new model improved MDPE, MDAPE, and Wobble values (11.5% ± 43.8%, 14.3% ± 33.0%, and 25.0% ± 21.3%, respectively). We created a new pharmacokinetic model for Japanese patients, which is more accurate than the three existing models applied to Japanese populations. Electronic document is a “live” template. The various components of your paper [title, text, heads, etc.] are already defined on the style sheet, as illustrated by the portions given in this document.

Low-dose S+ ketamine in target-controlled intravenous anaesthesia with remifentanil and propofol for open gynaecological surgery: A randomised controlled trial.

Background and Aims:Using remifentanil–propofol target-controlled infusion (TCI) in open gynaecological surgeries could be associated with opioid-induced hyperalgesia postoperatively. This study's aim was to investigate the effect of low-dose S-ketamine compared with control on cumulative morphine consumption 24 h postoperatively in women undergoing open abdominal hysterectomy with remifentanil–propofol TCI technique.Methods:Ninety female patients above 21 years old who underwent elective open abdominal hysterectomy under general anaesthesia with remifentanil–propofol TCI were recruited. They were randomised to receive either normal saline as control (n = 44) or 0.25 mg/kg intravenous boluses of S-ketamine before skin incision and after complete removal of uterus (n = 45). The primary outcome measure was cumulative morphine consumption measured over 24 h postoperatively. The secondary outcome measures were incidences of opioid-related and psychotomimetic side effects, pain and level of sedation scores.Results:The cumulative 24-h morphine consumption postoperatively (P = 0.0547) did not differ between both the groups. S-ketamine group had slower emergence from general anaesthesia (P = 0.0308) and lower pain scores (P = 0.0359) 15 min postoperatively. Sedation level, common opioid-related side effects (nausea, vomiting, pruritus), respiratory depression and psychotomimetic side effects were similar between both the study groups.Conclusion:Low-dose S-ketamine did not reduce the total cumulative morphine consumption in patients undergoing major open gynaecological surgeries with remifentanil–propofol TCI.

Propofol administration by anesthesiologists versus endoscopists during colonoscopy: Does it make a difference?

Background: Propofol anesthesia for endoscopic procedures has gained wide acceptance among physicians and patients. Much debate remains though whether propofol can be safely administered by non-anesthesiologists. Objective: To compare the procedural outcome of patients undergoing colonoscopy with Propofol target-controlled infusion administered by anesthesiologists vs. non-anesthesiologists. Design: A retrospective review. Setting: A private community hospital in Dubai, United Arab Emirates. Patients and Methods: All consecutive patients (age > 13 years, with American Society of Anesthesiologists class I-II and no other contraindications to administration of sedation by non-anesthesiologists) who underwent colonoscopy between January 1, 2017 and September 30, 2017. In the initial part of the study, propofol was administered by an anesthesiologist until the endoscopists were trained to provide propofol anesthesia via targeted-controlled infusion [TCI] by syringe pump. Intraprocedural data was collected in a prospective registry. Statistical analysis was performed using Chi square and student t test. Main Outcome Measures: Cecal intubation rate, procedural time, procedural-related complications, and polypectomy/biopsy rate. Sample Size: 347 patients. Results: Group 1 [anesthesiologists] 84 patients, Group 2 [endoscopists] 263 patients. Mean age was 44.8 and 46.9 years in Group 1 and 2, respectively (P = 0.17). There was no difference in gender distribution. The mean procedural time was 21 minutes in both groups (P = 0.93). The cecal intubation rate was similar [92.9% in Group 1 vs. 94.3% in Group 2, P = 0.40). No difference in procedural-related complications was noted between groups, with 1 patient in Group 2 sustaining endoscopic perforation during balloon dilation of a near obstructing anastomotic stricture. Except for the patient with endoscopic perforation, no patient required advanced airway management. Conclusions: Propofol can be safely administered by endoscopists using target-controlled infusion. Similar total procedural time and cecal intubation rate can be achieved without increased risk of procedural-related complications. Limitations: Retrospective review, community-based hospital, elective cases, small cohort size. Conflict of Interest: None.

Effect of dexmedetomidine on perioperative stress and postoperative pain in patients with radical resection of esophageal cancer under combined thoracoscope and laparoscope

Objective: To investigate the effects of dexmedetomidine on perioperative stress and postoperative pain in patients with radical resection of esophageal cancer under combined thoracoscope and laparoscope. Methods: In this prospective study, one hundred patients undergoing radical resection of esophageal cancer in Affiliated Cancer Hospital of Zhengzhou University from January 2016 to October 2017, were randomly divided into control group (group C) and dexmedetomidine group (group D), n=50. All patients were anaesthetized (induced and maintained) with intravenous target-controlled infusion(TCl) of propofol and remifentanil, and intermittent intravenous injection of cisatracuriumbesylate. Bispectral index(BIS) was used to monitor the depth of anesthesia and maintained between 45-60 during operation.All patients received sufentanil (0.3 μg/kg) 30 min before the end of the operation and then received intravenous analgesia pump for postoperative patient controlled analgesia(PCA). Patients in group D received intravenous infusion of dexmedetomidine(1 μg/kg) 20 min before anesthesia induction, followed by intravenous pumping of dexmedetomidine(0.2 μg·kg(-1)·h(-1)) intraoperatively.Postoperative intravenous patient-controlled analgesia(PCA) was performed in all patients, with background doses of sufentanil 0.04 μg· kg(-1)·h(-1) for patients in group C, and sufentanil 0.025 μg·kg(-1)·h(-1) plus dexmedetomidine 0.1 μg· kg(-1)·h(-1) for patients in group D. The operation time, liquid input and output during operation, the number of PCA pressings after operation were recorded. At these time points: T(0)(the day before operation), T(1)(immediate before anesthesia induction), T(2)(1 h after emergence), T(3)(24 h after operation), T(4)(3 d after operation), T(5)(7 d after operation), T(6)(one month after operation), T(7)(3 months after operation) and T(8)(6 month after operation) , venous blood samples of patients were collected for detection of epinephrine, norepinephrine and corticosterone. The pain visual analogue scale(VSA) was used to assess pain levels in patients at T(2), T(3), T(4), T(5), T(6), T(7), T(8). Results: The age, sex ratio, body mass index (BMI) and ASA grading ratio in two groups were not significantly different(all P>0.05). There were no Significant differences in operation time, liquid input and blood output between group C and group D(all P>0.05). Within 24 h after operation, the sufentanil consumption in group D[(35.86±8.65)μg]was significantly less than that in group C[(59.53±15.26) μg, t=7.061, P<0.05], and the number of PCA pressing in group D(2.15±1.38) was obviously less than that in group C(5.85±2.16, t=4.971, P<0.05). Compared with group C, serum norepinephrines in group D was significantly less (t=13.276, 16.027, 14.319, 12.771, 12.296, respectively; all P<0.05) at T(1), T(2), T(3), T(4), T(5).And there were no difference between these two groups at T(0), T(6), T(7), T(8)(all P>0.05). Serum epinephrine in group D were significantly lower than them in group C at T(2), T(3), T(4), T(5) (t=6.153, 8.774, 9.127, 8.409, respectively; all P<0.05), but there were no difference between these two groups at T(0), T(1), T(6), T(7), T(8)(all P>0.05). Serum corticosterone in group D were sharply less than them in group C at T(2), T(3), T(4), T(5) (t=16.364, 15.306, 12.153, 12.592, respectively; all P<0.05), but at T(0), T(1), T(6), T(7), T(8), there were no difference between these two groups (all P>0.05). Compared with group C, the number of patients with postoperative pain(VAS score≥4) in group D was obviously less at T(6), T(7), T(8)(10 vs 20, 4 vs 12, 3 vs 10; χ(2)=4.762, 4.762, 4.332, respectively; all P<0.05). Conclusion: Perioperative application of dexmedetomidine can effectively decrease the perioperative stress response, obviously cut down the perioperative opioid consumption, and prevent the transition from postoperative acute pain to chronic pain in patients with radical resection of esophageal cancer under combined thoracoscope and laparoscope.

Nonintubated laryngomicrosurgery with Transnasal Humidified Rapid-Insufflation Ventilatory Exchange: A case series

Nonintubation anaesthesia for laryngomicrosurgery (LMS) provides both excellent visualization of the surgical field and complete examination on vocal cord. However, adequate oxygenation remains challenging during nonintubated LMS. Recently, transnasal humidified rapid-insufflation ventilator exchange (THRIVE) has been reported effectively maintaining apneic oxygenation in patient with difficult airways. The feasibility and safety of nonintubated LMS with THRIVE was evaluated in this case series. From September 2016 to February 2017, a total of 23 patients receiving nonintubated LMS were included. Anaesthesia was induced and maintained through target-controlled propofol infusion and muscle relaxation with THRIVE oxygen support. Perioperative data were collected from medical records and analysed. The mean (±SD) duration of the operation was 12.4 (±4.4) min. The mean (±SD) total anaesthesia time (from induction to emergence) was 24.1 (±6.4) min. 22 patients received nonintubated LMS with surgical satisfaction without intraoperative desaturation. One patient who underwent laryngeal tumour biopsy experienced a single episode of desaturation. A 5.5-mm tracheal tube was needed for short-term mechanical ventilation to regain SpO2 to 100%. No significant complication was noted in all patients. All patients discharged as per schedule on the next day after surgery as intubated LMS patients in our hospital. Nonintubated LMS with THRIVE is a feasible and safe alternative to intubated LMS with a small size tracheal tube to provide a better surgical field. However, for patients with easy-bleeding tumor, intubated LMS remains suggestive for better airway protection.

Effects of neoadjuvant chemotherapy on the depth of total intravenous anesthesia in patients with breast cancer undergoing unilateral modified radical mastectomy: A prospective observational study.

Toxic effects of neoadjuvant chemotherapy (NC) on nervous, hepatorenal, and pulmonary systems might affect general anesthesia depth. This study aimed to evaluate the effects of NC on depth of total intravenous anesthesia.This prospective observational study enrolled 60 patients undergoing elective unilateral modified radical mastectomy during total intravenous anesthesia with propofol and remifentanil (January–June 2015; Liaocheng People's Hospital, China): the NC group (n = 30) received NC, while the control group (n = 30) did not. Propofol and remifentanil dosages were adjusted according to indexes of consciousness (IoC1: sedation; IoC2: analgesia) to control fluctuations of blood pressure and heart rate within 20% of baseline values. Parameters reflecting propofol/remifentanil dosages, intraoperative adverse events, and quality of anesthetic recovery were recorded.The duration of propofol infusion (1.3 ± 0.4 vs 1.8 ± 0.5 hours, P < .05), mean propofol dosage (8.0 ± 1.0 vs 9.3 ± 1.5 mg kg−1 h−1, P < .05), and adjustment frequency of target-controlled remifentanil infusion (2.9 ± 1.8 vs 4.4 ± 2.6 times/surgery, P < .05) were significantly lower in the NC group than in the control group; adjustment frequency of target-controlled propofol infusion was also numerically lower (2.0 ± 1.1 vs 2.7 ± 1.5 times/surgery, P = .053). Duration of remifentanil infusion, mean remifentanil dosage, voluntary eye opening, extubation time, and recovery score were not significantly different between groups. The incidence of tachycardia was lower in the NC group than in the control group (7.1% vs 37.0%, P < .05), but there was no significant difference in the incidence of total adverse events between groups.NC can enhance the sensitivity of breast cancer patients to the anesthetic effect of propofol.

Impact of CYP3A4*1G Polymorphism on Fentanyl Analgesia Assessed by Analgesia Nociception Index in Chinese Patients Undergoing Hysteroscopy.

Background:The clinical efficacy of fentanyl for pain control differs greatly across individuals. The purpose of this study was to investigate the impact of CYP3A4*1G polymorphism including wild-type homozygote (CYP3A4*1/*1, GG), mutant heterozygote (CYP3A4*1/*1G, GA), and mutant homozygote (CYP3A4*1G/*1G, AA) on fentanyl analgesia in Chinese patients undergoing hysteroscopy by the assessment of analgesia nociception index (ANI).Methods:A total of 200 gynecologic patients scheduled for elective hysteroscopy under general anesthesia at Peking University People's Hospital from May to December in 2017 were enrolled in this study. Venous blood was withdrawn for genotyping of CYP3A4*1G before operation. Fentanyl 1 μg/kg was administered preoperatively followed by target-controlled infusion of propofol for induction and maintenance. Intraoperative analgesic efficacy of fentanyl was assessed by ANI monitoring at T0 (entering room), T1 (cervical dilation), T2 (start of cervical aspiration), and T3 (end of cervical aspiration) time points. The duration of propofol infusion and total dosage of propofol were recorded as well.Results:The patients were divided into three groups according to CYP3A4*1G polymorphism, including 143 in GG group, 47 in GA group, and 10 in AA group. There was no significant difference in clinical demographics among three groups. The frequency of CYP3A4*1G variant alleles accounted for 16.8% and the distribution of variant alleles was consistent with Hardy–Weinberg equilibrium. Using a multilevel model, ANI values at T1 (63.81 ± 19.61), T2 (63.63 ± 17.82), and T3 (65.68 ± 17.79) were significantly lower than that at T0 (77.16 ± 12.93) in the study population (F = 23.50, P < 0.001), suggesting that higher levels of pain at T1, T2, and T3 than T0. Patients with GG genotype showed significantly lower ANI than those with GA or AA genotypes during hysteroscopy under the same dose of fentanyl.Conclusion:CYP3A4*1G polymorphism associated with the analgesic efficacy of intraoperative fentanyl in the patients undergoing hysteroscopy under general anesthesia.

Identifying consciousness alterations during intravenous anesthesia with the depth of anesthesia index and bispectral index: a randomized multicenter study

Objective To evaluate the validity of the depth of anesthesia index (Ai), based on sample entropy of electroencephalogram, in identifying the status of the consciousness during total intravenous anesthesia. Methods EEG electrode strips for recording Ai and BIS were randomly positioned on the left or right side of each patient′s forehead. Target-controlled infusion of propofol was increased by 0.5 mg/L per minute in a stepwise manner until loss of consciousness (LOC) was achieved. Values of Ai, BIS and estimated effect-site concentration (Ce) of propofol were recorded and analyzed during induction and emergence of general anesthesia. Logistic regression was used to analyze the relationship between consciousness state and values of Ai or BIS. Results One hundred and forty four patients in six medical centers were enrolled and have accomplished this protocol safely. In patients at LOC, the values of Ai and BIS were 61±12 and 62±11, which were respectively reduced by 15.0% and 9.3% one minute after LOC. When patients regained consciousness (ROC), Ai and BIS respectively reached 74±14 and 76±8, and increased by 15.0% and 7.0%, correspondingly, one minute after ROC. The estimated values of Ai and BIS were 48.3 and 52.3 for 95% LOC, and were 55.7 and 63.1 for 5% ROC. Conclusions At LOC, ROC, estimated 50% LOC and 50% ROC, the values of Ai and BIS were close to each other and they are equivalent for clinical monitoring. When consciousness states altered, changes of Ai were significantly greater than those of BIS. It suggests that Ai is a better parameter to estimate alterations of consciousness state. Key words: Loss of consciousness; Recovery of consciousness; Total intravenous anesthesia; Depth of anesthesia index; Bispectral index

Early post-operative cognitive dysfunction after closed-loop versus manual target controlled-infusion of propofol and remifentanil in patients undergoing elective major non-cardiac surgery: Protocol of the randomized controlled single-blind POCD-ELA trial.

Introduction:Post-operative cognitive dysfunction (POCD) is frequent in patients older than 60 years undergoing major non-cardiac surgery, and increases both morbidity and mortality. Anesthetic drugs may exert neurotoxic effects and contribute to the genesis of POCD. The hypothesis of the POCD-ELA trial was that closed-loop target-controlled infusion of propofol and remifentanil could reduce the occurrence of POCD by decreasing the risk of excessive depth of anesthesia and the dose of anesthetic drugs.Methods and analysis:We designed a single-center, single-blind, randomized, controlled, parallel trial and aim to include 204 patients aged >60 years undergoing elective major non-cardiac surgery. Patients will be randomized to receive closed-loop versus manual target-controlled infusion of propofol and remifentanil guided by bispectral index monitoring. Cognitive assessment will be performed the day before surgery (baseline) and within 72 hours after surgery, using a battery of validated neuropsychological tests. The primary outcome is the incidence of POCD within 72 hours after surgery. POCD is defined as a Z-score value > 1.96 for at least 2 different tests or a Z-score composite value >1.96. The calculation of the Z-score is based on data from an age-matched control population who did not undergo surgery or general anesthesia.Ethics and dissemination:This study was approved by the Ethics Committee (Comité de Protection des Personnes Est-II) and authorized by the French Health Products Agency (Agence Nationale de Sécurité des Médicaments, Saint-Denis, France). The University Hospital of Besancon is the trial sponsor and the holder of all data and publication rights. Results of the study will be submitted for publication in a peer-review international medical journal and for presentation in abstract (oral or poster) in international peer-reviewed congresses.Registration:The trial is registered with ClinicalTrials.gov (Identifier: NCT02841423, principal investigator: Prof Emmanuel Samain, date of registration: July 22, 2016). Last amendment of protocol: version 8.0 April 2018.