Comparison Between Esketamine and Alfentanil for Hysteroscopy: A Prospective, Double-Blind, Randomized Controlled Trial.

Purpose: This study aimed to establish the 95% effective dose (ED95) of esketamine in combination with propofol for hysteroscopy and then to evaluate its efficacy and safety profile. Patients and Methods: This prospective, double-blind, randomized controlled trial consisted of two cohorts. In cohort 1, 45 women aged 18-65 years undergoing hysteroscopy were randomly assigned to either group E (esketamine + propofol) or group A (alfentanil + propofol). Dixon's up-and-down method was used to determine the ED95 of esketamine and alfentanil. In cohort 2, 86 patients were randomized to group E and group A, with the calculated ED95 dose of the study drugs used for induction. The success rate of anesthesia using the ED95% dose, along with parameters related to anesthesia induction, recovery, and adverse events were also recorded. Results: The ED95 of esketamine was 0.254 mg/kg (95% CI: 0.214-1.004), while that of alfentanil was 9.121 µg/kg (95% CI: 8.479-13.364). The anesthesia success rate was 93.0% in group E and 95.2% in group A (p = 0.664). After resuscitation, both groups achieved a 100% success rate. The induction time was significantly shorter in group E (60.0 [55.0-70.0] s) compared to group A (67.0 [61.0-79.3] s) (p = 0.006). Group E had lower rates of respiratory depression (p < 0.001), hypoxia (p = 0.006), minimum perioperative SpO2 (p = 0.010), and hypotension (p = 0.001). Esketamine had less effect on respiratory rate, heart rate, mean blood pressure, and end-tidal carbon dioxide compared to alfentanil (all p < 0.001). There were no significant differences in postoperative pain between the two groups. Conclusion: This study determined the ED 95 dose of esketamine for intravenous general anesthesia during hysteroscopy. Esketamine showed less respiratory and hemodynamic depression, as well as fewer adverse effects compared to alfentanil. Esketamine is an ideal anesthetic agent compared to alfentanil for hysteroscopic anesthesia. Trial Registration: www.chictr.org.cn, (ChiCTR2300077283); registered November 3, 2023.

Effects of different doses of alfentanil on cardiovascular response to rapid sequence intubation in elderly patients: a parallel-controlled randomized trial.

BACKGROUND: Rapid sequence intubation (RSI) have been shown to be effective in preventing reflux aspiration in patients with a full stomach during anaesthesia induction and endotracheal intubation. However, there is currently no standardized operation protocol or anaesthesia induction drug standard for RSI. Furthermore, there is a lack of evidence regarding the use of RSI in patients older than 65. In this study, we aimed to investigate the cardiovascular effects of different doses of alfentanil combined with propofol and etomidate during RSI in elderly patients aged 65-80 years. METHODS: A total of 96 patients aged 65-80 years who underwent general anaesthesia with tracheal intubation were selected for this study. The patients were randomly assigned to one of four groups using a random number table. Group A patients received an induction dose of 10 µg/kg alfentanil, group B patients received 15 µg/kg alfentanil, group C patients received 20 µg/kg alfentanil, and group D patients received 25 µg/kg alfentanil. Heart rate (HR), mean arterial pressure (MAP), cardiac index (CI), and ejection fraction (EF) were measured at three time points: 5 min before anaesthesia induction (T0), 1 min after endotracheal intubation (T1), and 5 min after endotracheal intubation (T2). Concurrently, 4 ml of arterial blood was collected from patients at three time points, and the concentrations of norepinephrine (NE) and cortisol (Cor) in plasma were detected. Occurrences of hypertension, hypotension, bradycardia and tachycardia during anesthesia induction to 5 min after tracheal intubation were noted. RESULTS: Compared with T0, the HR, MAP, NE and Cor concentrations in group A and group B were increased at the T1 and T2 time points, CI and EF values were decreased (P < 0.05). HR and MAP in groups C and D were increased at the T1 time point, while they were decreased at the T2 time point in group D (P < 0.05). The changes in CI and EF values, concentrations of NE and Cor, were not significant at T1 and T2 time points in group C (P > 0.05). Additionally, they were not significant in group D at the T1 time point (P > 0.05), but decreased at the T2 time point (P < 0.05). Compared with group A, the HR, MAP, NE and Cor concentrations in groups C and D were decreased at T1 and T2 time points (P < 0.05). The CI and EF values of groups C and D were increased at T1 time point but decreased at T2 time point in group D (P < 0.05). The incidence of hypertension and tachycardia in group A was significantly higher than that in group C and group D (P < 0.05), and the incidence of hypotension and bradycardia in group D was significantly higher than that in group A and group B (P < 0.05). CONCLUSION: Alfentanil 20 µg/kg for RSI in elderly patients, can effectively inhibit the violent cardiovascular reaction caused by intubation, and avoid the inhibition of cardiovascular system caused by large dose, hemodynamics more stable. TRIAL REGISTRATION: ChiCTR2200062034 ( www.chictr.org.cn ).

Determination of ED50 and ED95 of remimazolam besylate combined with alfentanil for adult gastroscopy: a prospective dose-finding study.

BACKGROUND: To explore the median effective dose (ED50) and 95% effective dose (ED95) of remimazolam besylate combined with alfentanil for adult gastroscopy. METHODS: This prospective studyenrolled 31 patients scheduled to painless gastroscopy at Anhui No. 2 Provincial People's Hospital between April and May, 2022. 5 µg.kg-1 of alfentanil hydrochloride was used for pre-analgesia. The initial single loading dose of remimazolam besylate was 0.12 mg.kg-1, increased or reduced by 0.01 mg.kg-1 for the next patient with modified Dixon sequential method. The modified Observer's Assessment of Alertness/Sedation Scale (MOAA/S) was used to assess sedation. RESULTS: Combined with alfentanil, the ED50 of remimazolam besylate was 0.147 mg.kg-1 (95% CI: 0.138-0.160 mg.kg-1) and ED95 0.171 mg.kg-1 (95% CI: 0.159-0.245 mg.kg-1). The induction time after injection of remimazolam besylate was 70 ± 25 s, with the anesthesia recovery time and the observation time in resuscitation room 5.13 ± 2.13 min and 2.32 ± 1.6 min, respectively. Twenty nine patients' vital signs were within acceptable limits during gastroscopy. CONCLUSIONS: The ED50 of remimazolam besylate combined with alfentanil for painless gastroscopy was 0.147 mg.kg-1, and the ED95 was 0.171 mg.kg-1.

Low-Dose Alfentanil Inhibits Sufentanil-Induced Cough During Anesthesia Induction: A Prospective, Randomized, Double-Blind Study.

Background: Cough is one of the most common complications following intravenous administration of sufentanil during anesthesia induction. The study aimed to investigate the protective effect of alfentanil, afentanyl derivative with short onset time and short duration, in reducing sufentanil-induced cough. Patients and methods: Eighty patients that scheduled for thyroid surgery under general anesthesia were randomly divided into the alfentanil group and normal saline group, with 40 cases per group. Patients in the alfentanil group received intravenous administration of 2 µg/kg alfentanil prior to sufentanil injection during general anesthesia induction, while the same dose of normal saline was administered in the normal saline group. The outcomes measures included the incidence and severity of cough and common side effects of opioids following the administration of sufentanil during the induction of general anesthesia, intraoperative hemodynamics parameters and major adverse events during anesthesia recovery period. Results: The incidence of cough within one minute after the injection of sufentanil during anesthesia induction was 40% in the normal saline group, and the pretreatment of alfentanil significantly reduced the incidence of sufentanil-induced cough to 5% (p < 0.05). Correspondingly, the patients in the alfentanil group had decreased severity of sufentanil-induced cough compared with the normal saline group (p < 0.05). No significant differences in the incidences of common side effects of opioids (dizziness, nausea and vomiting, chest tightness and respiratory depression) within one minute after sufentanil injection were found (p > 0.05). Furthermore, there were no significant differences between the two groups in intraoperative hemodynamic parameters, extubation time, or the incidences of emergence agitation, respiratory depression, delayed recovery from anesthesia and postoperative nausea and vomiting during Postanesthesia Care Unit stay (p > 0.05). Conclusion: Pretreatment with low-dose alfentanil (2 µg/kg) effectively and safely reduced both the incidence and severity of sufentanil-induced cough during anesthesia induction. Clinical Trial Registration Number: Chinese Clinical Trial Registry (identifier: ChiCTR2300069286).

The 90% effective concentration of alfentanil combined with 0.075% ropivacaine for epidural labor analgesia: a single-center, prospective, double-blind sequential allocation biased-coin design.

PURPOSE: More literature studies have reported that alfentanil is safe and effective for labor analgesia. However, there is no unified consensus on the optimal dosage of alfentanil used for epidural analgesia. This study explored the concentration at 90% of minimum effective concentration (EC90) of alfentanil combined with 0.075% ropivacaine in patients undergoing epidural labor analgesia to infer reasonable drug compatibility and provide guidance for clinical practice. METHODS: In this prospective, single-center, double-blind study, a total of 45 singleton term primiparas with vaginal delivery who volunteered for epidural labor analgesia were recruited. The first maternal was administered with 3 µg/mL alfentanil combined with 0.075% ropivacaine with the infusion of 10 mL of the mixture every 50 min at a background dose of 3 mL/h. In the absence of PCEA, a total of 15 mL of the mixture is injected per hour. The subsequent alfentanil concentration was determined on the block efficacy of the previous case, using an up-down sequential allocation with a bias-coin design. 30 min after epidural labor analgesia, the block of patient failed with visual analog score (VAS) > 3, the alfentanil concentration was increased in a 0.5 µg/mL gradient for the next patient, while the block was successful with VAS ≤ 3, the alfentanil concentration was remained or decreased in a gradient according to a randomized response list for the next patient. EC90 and 95% confidence interval were calculated by linear interpolation and prediction model with R statistical software. RESULTS: In this study, the estimated EC90 of alfentanil was 3.85 µg/mL (95% confidence interval, 3.64-4.28 µg/mL). CONCLUSION: When combined with ropivacaine 0.075%, the EC90 of alfentanil for epidural labor analgesia is 3.85 µg/mL in patients undergoing labor analgesia.

Randomized, Single-Blind, Comparative Study of Remimazolam Besylate vs Propofol for Facial Plastic Surgery.

BACKGROUND: Use of local anesthesia and conscious sedation with a combination of a sedative and anesthetic drug during a surgical procedure is an approach designed to avoid intubation, which produces fewer adverse events compared to general anesthesia. In the present study, a comparison was made between the efficacy and safety of remimazolam besylate and propofol for facial plastic surgery. OBJECTIVES: The objective was to evaluate the clinical efficacy, comfort, and incidence of adverse events of remimazolam compared with propofol combined with alfentanil in outpatient facial plastic surgery. METHODS: In this randomized, single-blind, single-center, comparative study, facial plastic surgery patients were randomly divided into remimazolam-alfentanil (n = 50) and propofol-alfentanil (n = 50) groups for sedation and analgesia. The primary endpoint was the incidence of hypoxemia, while secondary endpoints included efficacy and safety evaluations. RESULTS: There were no significant differences regarding the surgical procedure, sedation and induction times, pain and comfort scores, muscle strength recovery, heart rate, respiratory rate, and blood pressure, but the dosage of alfentanil administered to the remimazolam group (387.5 µg) was lower than that for the propofol group (600 µg). The incidence of hypoxemia (P = .046) and towing of the mandibular (P = .028), as well as wake-up (P = .027) and injection pain (P = .008), were significantly higher in the propofol group than the remimazolam group. CONCLUSIONS: Remimazolam and propofol had similar efficacies for sedation and analgesia during facial plastic surgery, but especially the incidence of respiratory depression was significantly lower in patients given remimazolam.

Effect of electroacupuncture on sedation requirements during colonoscopy: a prospective placebo-controlled randomised trial.

INTRODUCTION: Propofol provides excellent sedation during colonoscopy. However, its application, namely when used together with an opioid, is associated with cardiopulmonary depression. Acupuncture is used nowadays for the treatment of pain and anxiety, and also to induce sedation. We hypothesised that electroacupuncture (EA) during colonoscopy would have sedative effects, thereby reducing propofol requirements to achieve an adequate level of sedation. METHOD: The study was designed and conducted as a single centre, patient and observer blinded, sham- and placebo-controlled randomised trial. Patients scheduled for elective colonoscopy under deep propofol/alfentanil sedation were randomly assigned to receive unilateral EA, sham-acupuncture (SA) or placebo-acupuncture (PA) at ST36, PC6 and LI4. The primary outcome parameter was the total dosage of propofol. Secondary outcomes included the patients' and endoscopists' satisfaction levels evaluated by questionnaires. RESULTS: The dosage of propofol required (median [IQR]) was not significantly different between the three groups (EA group 147 µg/kg/min [109-193] vs SA group 141 µg/kg/min [123- 180] vs PA group 141 µg/kg/min [112-182]; P=0.776). There was also no significant difference in alfentanil consumption (P=0.634). Global satisfaction (median [IQR]) among patients (EA group 6.6 [6.0-7.0] vs SA group 6.8 [6.0-7.0] vs PA group 6.5 [6.0-7.0]; P=0.481) and endoscopists (6.0 [5.0-6.0] for all groups; P=0.773) did not significantly differ between the three groups. There was no significant difference in the number of cardiorespiratory events. CONCLUSION: For colonoscopy, the applied mode of EA did not show any propofol-sparing sedative effect compared with sham or placebo acupuncture. TRIAL REGISTRATION: The trial is registered in the Netherland's Trial Registry (NTR4325).

Evaluation of two different radiotherapy anaesthetic protocols for dogs: a randomized clinical crossover trial.

OBJECTIVES: To describe alfentanil-propofol admixture for induction of anaesthesia for canine radiotherapy and compare it to alfentanil-atropine followed by propofol induction in terms of heart rate (HR), mean arterial pressure (MAP), recovery duration and quality. STUDY DESIGN: Prospective, masked, randomized clinical crossover trial. ANIMALS: A group of 40 client-owned dogs anaesthetized from October 2017 to June 2018. METHODS: Dogs were randomly assigned to be administered one of two protocols. For both protocols, IV preanaesthetic medication was given 30 seconds before rapid IV administration of a set volume of induction agent, with further induction agent administered as needed to permit intubation. For protocol ADMIX, the preanaesthetic medication was 0.04 mL kg-1 0.9% sodium chloride and the induction agent was 0.2 mL kg-1 propofol-alfentanil admixture. For protocol ATRO, the preanaesthetic medication was 10 µg kg-1 alfentanil with 12 µg kg-1 atropine (0.04 mL kg-1 total volume) and the induction agent was 0.2 mL kg-1 propofol. Anaesthesia was maintained with sevoflurane. Cardiorespiratory variables, agitation, hypotension, or inadequate depth of anaesthesia requiring supplemental boluses of propofol or increased vaporizer settings were recorded. Time to extubation, sternal recumbency and walking was noted. Videos were recorded for recovery quality scoring. Owner questionnaires gave feedback about recoveries at home. The other protocol was administered for the next radiotherapy session. RESULTS: The only significantly different variable between protocols was mean HR during anaesthesia, which was lower in ADMIX (p < 0.001). Hypotension was recorded in seven (17.5%) dogs in ATRO and three (7.5%) in ADMIX, with an association (p < 0.005) between ATRO and hypotension. Owners reported animals recovered 'normal' behaviour and appetite by the next morning. CONCLUSIONS AND CLINICAL RELEVANCE: Both protocols were acceptable for dogs undergoing radiotherapy, with minimal differences in anaesthetic quality, recovery duration and quality. Although MAP did not differ overall, the incidence of hypotension was higher in ATRO.

Plasma concentration based response surface model predict better than effect-site concentration based model for wake-up time during gastrointestinal endoscopy sedation.

BACKGROUND: Sedation for esophagogastroduodenoscopy (EGD) and colonoscopy is characterized by rapid patient induction and emergence. The drugs midazolam and alfentanil have long been used for procedural sedation; however, the relationship between plasma or effect-site concentrations (Cp or Ce, respectively) and emergence remains unclear. The aim of this study is to develop patient wake-up prediction models for both Cp and Ce using response surface modeling, a pharmacodynamics tool for assessing patients' responses. METHODS: The Observer's Alertness/Sedation (OAA/S) score was used to monitor sedation depth during the examinations. Concentration pairs of midazolam and alfentanil were calculated for each of Cp and Ce using pharmacokinetic simulation software. Response surface models were developed using the Greco construct. Temporal analysis was done by comparing model-predicted wake-up time with true patient wake-up time. RESULTS: Thirty-three patients with an average body mass index of 21.85 ± 2.3 kg/m2 were pooled for analysis. The average duration of examination were 2.9 ± 1.4 min for EGD and 6.6 ± 2.7 min for colonoscopy. Seventy-five concentration pairs of midazolam and alfentanil were obtained for each Cp and Ce. The Cp-based Greco response surface model showed significant synergy between midazolam and alfentanil and was a better predictor of patient wake-up time, with an average deviation of 1.0 ± 3.9 min, while the Ce model show time deviation greater than 20 min. CONCLUSION: The early phases of drug distribution are unique and complicated by nonsteady-state concentrations, and our study revealed that Ce-based wake-up time prediction is more difficult under these circumstances.

Pupillary Pain Index Changes After a Standardized Bolus of Alfentanil Under Sevoflurane Anesthesia: First Evaluation of a New Pupillometric Index to Assess the Level of Analgesia During General Anesthesia.

BACKGROUND: The pupillary pain index (PPI) is a novel pupillometric index, designed to assess intraoperative analgesia. It is based on the evaluation of the pupillary response to electrical stimuli of increasing intensity. It ranges from 1 (low level of pupillary reactivity, high level of analgesia) to 10 (high level of pupillary reactivity, low level of analgesia). In this first evaluation of the PPI, our objective was to investigate the PPI changes after a bolus of 10 µg·kg(-1) of alfentanil in children under sevoflurane general anesthesia. METHODS: After ethics committee approval and informed consent, 20 healthy children (9 ± 5 years) undergoing elective surgery under general anesthesia were included in this prospective, open, registered pilot study (NCT02646592). Anesthetic induction was standardized with sevoflurane 6% and propofol 1 mg·kg(-1). After tracheal intubation, sevoflurane concentration was maintained at 2% for 10 minutes. A first PPI measurement was performed (PPI-1), and a bolus of 10 µg·kg(-1) was administered. Two minutes after this bolus, a second PPI measurement was performed (PPI-2). Heart rate, blood pressure, and bispectral index were recorded before and after each PPI measurement. Resting pupillary diameter was recorded before each PPI measurement. PPI scores before and after the bolus of alfentanil were compared using a Wilcoxon signed rank test. RESULTS: PPI scores decreased after administration of a bolus of alfentanil (median difference: -3 [95% confidence interval, -4 to -2]). The median (quartiles) of PPI-1 (baseline, before alfentanil) was 6 (4, 7), and the median (quartiles) of PPI-2 (after alfentanil) was 2 (2, 3) (P < .001). No difference was found in resting pupillary diameter before PPI-1 and PPI-2 (2.2 ± 0.2 and 2.2 ± 0.3 mm, respectively; P = .86). There were no significant changes in heart rate or blood pressure after PPI measurements (P = .46 and .49, respectively). Bispectral index was slightly increased after PPI measurements (P = .01; mean bispectral index increase <5%). No withdrawal movements occurred during PPI measurements. CONCLUSIONS: There was a significant decrease in PPI after alfentanil administration. The results of this pilot study suggest that PPI score decreases when the level of analgesia increases. PPI measurement was not associated with a clinical or hemodynamic nociceptive response. This new index might provide useful information to individually adapt opioid administration before nociceptive stimuli under general anesthesia.

Patient response prediction with logistic regression in gastrointestinal endoscopy under midazolam-alfentanil sedation performed as well as response surface model.

BACKGROUND: Researchers have used logistic regression (LR) and non-linear response surface models (RSMs) to predict patient responses to sedation. The reduced Greco and hierarchy RSMs have proven to be more appropriate than other RSMs in gastrointestinal endoscopies using midazolam and alfentanil. In this study, we evaluate the performance of a simpler model, LR, and compared it with that of RSM. METHODS: Thirty-three patients who received esophagogastroduodenoscopy (EGD) and colonoscopy sedation with midazolam and alfentanil were enrolled in the study. LR was performed for the EGD group and validated using the colonoscopy group. The two RSMs were performed using the same process, and performances and receiver operating characteristic (ROC) curves of the models were evaluated. RESULTS: The native EGD LR model had an ROC curve area of 0.94. For external validation, the ROC curves were 0.92, 0.94, and 0.94 for the reduced Greco, hierarchy, and LR models, respectively. Pairwise comparison between models was not significant. CONCLUSION: The LR model performed as well as RSM in generalizing the predicted sedative effect of midazolam and alfentanil during gastrointestinal endoscopies. LR may be used for generalization across patients experiencing procedures with similar stimulus intensities.

Adaptation of non-linear mixed amount with zero amount response surface model for analysis of concentration-dependent synergism and safety with midazolam, alfentanil, and propofol sedation.

BACKGROUND: The non-linear mixed amount with zero amounts response surface model can be used to describe drug interactions and predict loss of response to noxious stimuli and respiratory depression. We aimed to determine whether this response surface model could be used to model sedation with the triple drug combination of midazolam, alfentanil and propofol. METHODS: Sedation was monitored in 56 patients undergoing gastrointestinal endoscopy (modelling group) using modified alertness/sedation scores. A total of 227 combinations of effect-site concentrations were derived from pharmacokinetic models. Accuracy and the area under the receiver operating characteristic curve were calculated. Accuracy was defined as an absolute difference <0.5 between the binary patient responses and the predicted probability of loss of responsiveness. Validation was performed with a separate group (validation group) of 47 patients. RESULTS: Effect-site concentration ranged from 0 to 108 ng ml-1 for midazolam, 0-156 ng ml-1 for alfentanil, and 0-2.6 µg ml-1 for propofol in both groups. Synergy was strongest with midazolam and alfentanil (24.3% decrease in U50, concentration for half maximal drug effect). Adding propofol, a third drug, offered little additional synergy (25.8% decrease in U50). Two patients (3%) experienced respiratory depression. Model accuracy was 83% and 76%, area under the curve was 0.87 and 0.80 for the modelling and validation group, respectively. CONCLUSION: The non-linear mixed amount with zero amounts triple interaction response surface model predicts patient sedation responses during endoscopy with combinations of midazolam, alfentanil, or propofol that fall within clinical use. Our model also suggests a safety margin of alfentanil fraction <0.12 that avoids respiratory depression after loss of responsiveness.

Pharmacokinetics of Fentanyl and Its Derivatives in Children: A Comprehensive Review.

Fentanyl and its derivatives sufentanil, alfentanil, and remifentanil are potent opioids. A comprehensive review of the use of fentanyl and its derivatives in the pediatric population was performed using the National Library of Medicine PubMed. Studies were included if they contained original pharmacokinetic parameters or models using established routes of administration in patients younger than 18 years of age. Of 372 retrieved articles, 44 eligible pharmacokinetic studies contained data of 821 patients younger than 18 years of age, including more than 46 preterm infants, 64 full-term neonates, 115 infants/toddlers, 188 children, and 28 adolescents. Underlying diagnoses included congenital heart and pulmonary disease and abdominal disorders. Routes of drug administration were intravenous, epidural, oral-transmucosal, intranasal, and transdermal. Despite extensive use in daily clinical practice, few studies have been performed. Preterm and term infants have lower clearance and protein binding. Pharmacokinetics was not altered by chronic renal or hepatic disease. Analyses of the pooled individual patients' data revealed that clearance maturation relating to body weight could be best described by the Hill function for sufentanil (R 2 = 0.71, B max 876 mL/min, K 50 16.3 kg) and alfentanil (R 2 = 0.70, B max (fixed) 420 mL/min, K 50 28 kg). The allometric exponent for estimation of clearance of sufentanil was 0.99 and 0.75 for alfentanil clearance. Maturation of remifentanil clearance was described by linear regression to bodyweight (R 2 = 0.69). The allometric exponent for estimation of remifentanil clearance was 0.76. For fentanyl, linear regression showed only a weak correlation between clearance and bodyweight in preterm and term neonates (R 2 = 0.22) owing to a lack of data in older age groups. A large heterogeneity regarding study design, clinical setting, drug administration, laboratory assays, and pharmacokinetic estimation was observed between studies introducing bias into the analyses performed in this review. A limitation of this review is that pharmacokinetic data, based on different modes of administration, dosing schemes, and parameter estimation methods, were combined.

A randomized double-blind controlled trial comparing three sedation regimens during flexible bronchoscopy: Dexmedetomidine, alfentanil and lidocaine.

INTRODUCTION: No standardized sedation protocol is available for flexible bronchoscopy (FB). OBJECTIVES: The aim of this study was to evaluate the efficacy and safety of three regimens used for sedation during FB. METHODS: This randomized double-blind controlled trial assessed patients undergoing bronchoscopy and receiving lidocaine alone (C) or combined with dexmedetomidine (D) or alfentanil (A). Tolerance was assessed using the bronchoscopy score, and level of sedation was assessed using the Nursing Instrument for the Communication of Sedation. Safety was evaluated in terms of pulmonary function and vital signs. RESULTS: A total of 162 patients were enrolled. The bronchoscopy score was identical in all groups. Group D subjects were the most sedated (P = .013), whereas group A subjects were the least agitated. Linear regression showed a negative association between bronchoscopy score and age in A (ß = -0.06; P = .001). Positive predictors of bronchoscopy score were female gender (ß = 1.96; P = .003) in D and obesity (ß = 2.41; P = .012), longer procedures (ß = 0.08; P = .009) and female gender (ß = 1.15; P = .038) in C. Longer procedures (ß = -0.12; P = .010) was a negative predictor of bronchoscopy score in D. Desaturation, hypoxia and heart rate changes were most prevalent in group A. Hypotension was mostly observed in D. CONCLUSIONS: No consistent differences were present between the three regimens; however, each was more appropriate in certain patient profiles. We consequently proposed a protocol as a first step towards standardizing sedation practice in FB in a patient-tailored manner. A more comprehensive and detailed protocol including other sedative agents with their corresponding doses should be developed.

Effects of alfentanil or fentanyl added to propofol for sedation in colonoscopy on cognitive functions: Randomized controlled trial.

BACKGROUND/AIMS: To assess the effect of propofol supplemented with alfentanil or fentanyl on cognitive functions for sedation during elective colonoscopy. MATERIALS AND METHODS: Patients (n=150, 18-65 years old, American Society of Anesthesiologists risk group I-III) scheduled undergo elective colonoscopy were included. They were randomized into three groups using the closed envelope methodpropofol-alfentanil (Group A), propofol-fentanyl (Group F), and propofol only (Group P).Group A patients were given an alfentanil (10 mcg/kg)-supplemented propofol bolus infusion and 5 mcg/kg alfentanil when necessary. Group F patients were given fentanyl (1 mcg/kg)-supplemented propofol and 0.5 mcg/kg fentanyl when necessary. Group P patients were given 1 mg/kg propofol and 0.5 mg/kg propofol when necessary. Vital signs, depth of sedation, recovery parameters, and patient and endoscopist satisfaction were recorded. Trieger dot test (TDT) and Digit Symbol Substitution Test (DSST) were performed post procedure. RESULTS: Demographic data were similar among all patients in the groups. Bispectral index values were lower in Group P (p<0.001). DSST scores were higher in Group A (p=0.004). TDT scores and Facial Pain Scale scores were higher in Group P (p<0.005). Apnea incidence (p=0.009) and Observer's Assessment of Alertness/Sedation Scale scores (p=0.002) were also higher in Group P. Patient satisfaction and endoscopist satisfaction were similar among all patients. CONCLUSIONS: Compared with propofol-alfentanil and propofol-fentanyl, propofol alone is associated with an increased incidence of apnea, drug consumption, and reported pain. Propofol-alfentanil has a less negative effect on cognitive functions than propofol alone or propofol-fentanyl.

Investigating Power Density and the Degree of Nonlinearity in Intrinsic Components of Anesthesia EEG by the Hilbert-Huang Transform: An Example Using Ketamine and Alfentanil.

Empirical mode decomposition (EMD) is an adaptive filter bank for processing nonlinear and non-stationary signals, such as electroencephalographic (EEG) signals. EMD works well to decompose a time series into a set of intrinsic mode functions with specific frequency bands. An IMF therefore represents an intrinsic component on its correspondingly intrinsic frequency band. The word of 'intrinsic' means the frequency is totally adaptive to the nature of a signal. In this study, power density and nonlinearity are two critical parameters for characterizing the amplitude and frequency modulations in IMFs. In this study, a nonlinearity level is quantified using degree of waveform distortion (DWD), which represents the characteristic of waveform distortion as an assessment of the intra-wave modulation of an IMF. In the application of anesthesia EEG analysis, the assessments of power density and DWD for a set of IMFs represent dynamic responses in EEG caused by two different anesthesia agents, Ketamine and Alfentanil, on different frequency bands. Ketamine causes the increase of power density and the decrease of nonlinearity on γ-band neuronal oscillation, which cannot be found EEG responses of group B using Alfentanil. Both agents cause an increase of power density and a decrease of nonlinearity on ß-band neuronal oscillation accompany with a loss of consciousness. Moreover, anesthesia agents cause the decreases of power density and nonlinearity (i.e. DWD) for the low-frequency IMFs.

Alfentanil versus ketamine combined with propofol for sedation during upper gastrointestinal system endoscopy in morbidly obese patients.

OBJECTIVES: To observe the effects of both propofol/alfentanil and propofol/ketamine on sedation during upper gastrointestinal system endoscopy in morbidly obese patients (UGSEMOP). METHODS: In a prospective, double-blinded, randomized clinical study, 52 patients scheduled for UGSEMOP were assigned to either group A (n=26; 10 µg/kg intravenous [IV] alfentanil) or group K (n=26; 0.5 mg/kg IV ketamine). Each patient was administered 0.7 mg/kg propofol for induction. If it was needed, the patients were administered an additional dose of IV propofol. This study was performed in Sehitkamil State Hospital, Gaziantep, Turkey, between January 2014-2015. Total propofol consumption, time to achieve Modified Aldrete Scores (MAS) of 5 and 10 following the procedure, physician and patient satisfaction scores, and instances of side effects, such as bradycardia and hypotension were recorded. Results: Time to onset of sedation and duration of sedation were both significantly shorter in group A. Patients in group A also required less time to achieve an MAS of 5. Total propofol consumption was significantly lower in group A. CONCLUSION: Both propofol/alfentanil and propofol/ketamine combinations provided appropriate hypnosis and analgesia during UGSEMOP. However, propofol consumption was significantly higher using the propofol/ketamine combination.

The safety and efficacy of alfentanil-based induction in bronchoscopy sedation: A randomized, double-blind, controlled trial.

BACKGROUND: Alfentanil in combination with propofol produces a synergistic sedative effect in patients undergoing flexible bronchoscopy (FB). However, the use of this combination is controversial due to the risk of cardiopulmonary depression. The aim of this study was to evaluate the proper induction regimen of alfentanil in propofol target-controlled infusion for FB sedation. METHODS: One hundred seventy-three patients were assigned randomly into 5 regimens: Group 1 and 2, alfentanil 2.5 and 5 µg/kg, respectively, immediately before propofol administration; Group 3 and 4, alfentanil 2.5 and 5 µg/kg, respectively, 2 minutes before propofol administration; and Group 5, propofol administration alone to achieve the observer assessment of alertness and sedation scale 3∼2. The bronchoscopists, physicians in charge of sedation, and patients were blind to the regimens. Adverse events, drug dose, induction, procedure and recovery time, cough severity, and propofol injection related pain were recorded. RESULTS: The patients in groups 2 and 4 required a lower dose of propofol (P = 0.031 and 0.019, respectively) and shorter time (P = 0.035 and 0.010) than group 5 for induction. Patients in group 2 experienced more hypoxemia than those in group 5 during induction (P = 0.031). The physician in charge of sedation scored a lower severity of cough in the patients in group 4 than in groups 3 and 5. There were no differences in terms of propofol injection related pain among the groups. CONCLUSION: Alfentanil 5 µg/kg given immediately before propofol infusion cannot be recommended. Further study is required to define conclusions about alfentanil 2.5 and 5 µg/kg because of the low power rating of subgroup in the present study.