Clinical Pharmacokinetics and Pharmacodynamics of Propofol

The Effects of Gene Variations of GABRA2, GABRB1, GABRG2, GAD1 and SLC1A3 on Patients with Propofol During Anesthesia Induction

Purpose

Propofol is one of the most commonly used intravenous sedatives in general anesthesia, while the individual variations of propofol are apparent. The objective of this study was to investigate the influence of genetic variations in GABAergic neurons and glutamatergic neurons on time to loss of consciousness (LOC) and the incidence of hypotension during anesthesia induction.

Patients and Methods

A total of 140 Chinese patients undergoing thyroid surgery or breast surgery were recruited. Genotyping of candidate genes was carried out using the Agena Bioscience MassARRAY system. Anesthesia induction was initiated with a propofol target plasma concentration (Cp) of 4.0 μg mL⁻¹. The LOC latency, systolic blood pressure, diastolic blood pressure, mean arterial pressure were documented.

Results

We found that GABRA2 rs35496835, GABRB1 rs1372496, GABRG2 rs11135176, GABRG2 rs209358, GAD1 rs3791878, SLC1A3 rs1049522 and gender were significant determinants of the patient’s LOC latency following propofol administration. GABRA2 rs11503014 was highly correlated with blood pressure reduction during anesthesia induction. Multiple linear regression analysis revealed that GABRB1 rs1372496, GABRG2 rs11135176, and SLC1A3 rs1049522 accounted for 35.3% variations in LOC latency following propofol administration.

Conclusion

Our findings indicate that genetic variants of GABRA2, GABRB1, GABRG2, GAD1 and SLC1A3 may have influence on propofol susceptibility, which would be an important guidance towards building clinical models that can precisely predict the efficacy of propofol with various populations before surgery.

Safety, Pharmacokinetics, and Pharmacodynamics of a Single Bolus of the γ-aminobutyric Acid (GABA) Receptor Potentiator HSK3486 in Healthy Chinese Elderly and Non-elderly

Background: The present clinical trial investigated the potential influences of dosage and age on the pharmacokinetic properties and safety profile of HSK3486, and whether any adjustment in dosing regimen is necessary in elderly patients.

Methods: Twenty-four elderly participants (65–73 years) were apportioned to three equal cohorts to receive a single IV bolus of 0.2, 0.3, and 0.4 mg/kg HSK3486, respectively. An additional control group comprised eight non-elderly participants (21–44 years), who each received a single IV bolus dose of 0.4 mg/kg. Safety was assessed throughout the study, and the clinical effects were assessed based on modified observer’s assessment of alertness/sedation and bispectral index (BIS) monitor. Pharmacokinetic parameters were calculated.

Results: The rates of drug-related adverse reactions among the elderly groups were a little higher than that of the non-elderly, and were slightly higher in the elderly receiving 0.4 mg/kg compared with the elderly given lower doses. The pharmacokinetic characteristics of 0.4 mg/kg HSK3486 in the elderly and non-elderly were comparable. The time to recovery was similar in elderly 0.3 mg/kg, elderly 0.4 mg/kg and non-elderly 0.4 mg/kg groups. In the elderly 0.2 mg/kg group, the time to loss of consciousness was a little longer, and the time to recovery was shorter, relative to the other three groups.

Conclusions: Administration of 0.3 mg/kg to the elderly and 0.4 mg/kg to the non-elderly were similarly efficacious. A dose of HSK3486 of 0.3 mg/kg may be chosen for clinical use in elderly patients.

Propofol Ameliorates Exaggerated Human Neutrophil Activation in a LPS Sepsis Model

Background

Sepsis is a leading cause of morbidity and mortality worldwide. Many patients suffering from sepsis are treated on intensive care units and many of them require mechanical ventilation under sedation or general anesthesia. Propofol, a drug used for these purposes, is known to interact with polymorphonuclear granulocytes (PMNs). Therefore, the aim of this study was to investigate the influence of propofol on PMN functions after experimental Gram-negative induced sepsis using lipopolysaccharide (LPS) stimulation.

Methods

A total of 34 granulocyte-enriched samples were collected from healthy subjects. PMNs were isolated by density gradient centrifugation and incubated simultaneously with either 6 µg/mL or 60 µg/mL propofol, or none (control). Additionally, the experimental sepsis samples were incubated with either 40 pg/mL or 400 pg/mL LPS. Live cell imaging was conducted in order to observe granulocyte chemotactic migration, ROS production, and NETosis. Flow cytometry was used to analyze viability and antigen expression.

Results

Propofol led to significantly reduced PMN track length (p < 0.001) and track speed (p < 0.014) after LPS-induced sepsis in a dose-dependent manner. NETosis (p = 0.018) and ROS production (p = 0.039) were accelerated by propofol without LPS incubation, indicating improved immune function. Propofol also ameliorated LPS-induced increased NETosis and ROS-production. Antigen expression for CD11b, CD62l and CD66b was unaffected by propofol.

Conclusion

Propofol improves LPS-induced exaggerated PMN activation in an ex vivo model. Beneficial effects due to restored immune function in septic patients might be possible, but needs further investigation.

Using Population Pharmacokinetic Modeling to Estimate Exposure to Δ9-Tetrahydrocannabinol in an Observational Study of Cannabis Smokers in Colorado

BACKGROUND

Self-report questionnaires, weighing products consumed, and Δ9-tetrahydrocannabinol (THC) biomarkers are established techniques for estimating cannabis exposure. Population pharmacokinetic modeling of plasma THC and metabolite concentrations by incorporating self-reported and weighed products as covariates could improve estimates of THC exposure in regular cannabis users.

METHODS

In this naturalistic study, blood samples were obtained from 36 regular smokers of cannabis for analysis of THC and its 2 metabolites at 4 time points: recruitment and during an experimental mobile laboratory assessment that included 3 time points: before, immediately after, and 1 hour after ad libitum legal market flower use. These data were analyzed using an established model of population pharmacokinetics developed from laboratory-controlled cannabis administration data. Elimination and metabolite production clearances were estimated for each subject as well as their daily THC doses and the dose consumed during the ad libitum event.

RESULTS

A statistically significant correlation existed between the daily THC dose estimated by self-report questionnaire and population pharmacokinetic modeling (correlation coefficient = 0.79, P < 0.05) between the weighed cannabis smoked ad libitum and that estimated by population pharmacokinetic modeling (correlation coefficient = 0.71, P < 0.05).

CONCLUSION

Inclusion of self-reported questionnaire data of THC consumption improved pharmacokinetic model-derived estimates based on measured THC and metabolite concentrations. In addition, the pharmacokinetic-derived dose estimates for the ad libitum smoking event underestimated the THC consumption compared with the weighed amount smoked. Thus, the subjects in this study, who smoked ad libitum and used cannabis products with high concentrations of THC, were less efficient (lower bioavailability) compared with computer-paced smokers of low potency, NIDA cannabis in a laboratory setting.

Quantitative analysis of human brain microdialysate for target site pharmacokinetics of major anesthetics ketamine, midazolam and propofol

Brain microdialysis samples of intensive care patients treated with the essential anesthetics ketamine, midazolam and propofol were investigated. Importantly, despite decades of clinical use, comprehensive human cerebral pharmacokinetic data of these drugs is still missing. To encounter this apparent lack of knowledge, we combined cerebral microdialysis with leading-edge analytical instrumentation to monitor the neurochemistry of living human patients. For the quantitative analysis, high performing analytical approaches were developed that can handle minute sample volumes and possible ultralow target analyte levels. The developed methods provided detection limits below 100 ng L^-1 for all target analytes and high precision (below 4% RSD intraday). Methods were linear between LODs and 100 μg L^-1 for ketamine, 75 μg L^-1 for midazolam and 10 μg L^-1 for propofol respectively, with coefficients of determination R²≥ 0.999. Further, being aware of the error-prone and demanding translation of microdialysis levels to interstitial concentrations, in vitro approaches for recovery testing of microdialysis probes as well as internal normalization approaches were conducted. Thus, we herein report the first cerebral pharmacokinetic data of ketamine, midazolam and propofol determined in microdialysis samples of 15 neurointensive care patients. We could prove blood-brain barrier penetration of all of the investigated anesthetics and could correlate applied dosages and actual brain exposition of ketamine. However, we emphasize the need of an expanded prospective study including individual microdialysis recovery testing as well as matched serum and/or cerebrospinal fluid collection for a more comprehensive cerebral pharmacokinetic understanding.

Effectiveness and Safety of Intravenous Sedation with Propofol in Non-Operating Room Anesthesia (NORA) for Dental Treatment in Uncooperative Paediatric Patients

Background: Uncooperative children require sedative approach for dental treatment. The aim was to assess the effectiveness of Propofol in “Non-Operating Room Anesthesia” (NORA) for paediatric dental treatment; intraoperative side effects; postoperative side effects; post-discharge effects. Methods: a prospective study, involving 109 uncooperative children undergoing sedation in NORA using Propofol for dental treatment, was performed. Working sessions, success/failure, intraoperative and postoperative side effects, number of treatment; type of procedure were assessed. Parents completed a post-discharge questionnaire on: pain; crying; fever; vomiting; headache; drowsiness; excitability; irritability; ability to eat; drugs and medical care needing. Results: Success: 96.7%. Intraoperative side effects: 33.3%. Postoperative side effects: 6.4%. Statistically significant association between: intraoperative side effects and age (p = 0.001), health status (p = 0.0007), weight (p = 0.038), respectively; intraoperative side effects and number/ type of dental treatment (p = 0.0055) and scaling (p = 0.0001), respectively. For post-discharge questionnaires, statistically significant association between: age and crying (p = 0.0001) and headache (p = 0.002), respectively; health status and crying (p = 0.015) and drugs needing (p = 0.04), respectively; weight and crying (p = 0.0004); extraction and pain (p = 0.0001) and crying (p= 0.0073), respectively; scaling and crying (p = 0.04), excitability and irritability (p = 0.03), respectively. Conclusion: Propofol in NORA was effective with minimal side effects.

Propofol Suppresses Cell Progression by Inhibiting CCL18 Expression in Hepatoblastoma

Background

Propofol is an anesthetic commonly used clinically and has been found to have antitumor activity in various cancers. The purpose of this study was to investigate the role of propofol in hepatoblastoma (HB).

Methods

CCK-8 and transwell were used to measure cell proliferation, migration, and invasion in HB cells. Cell apoptosis rate was measured by FCM. The expression of CCL18 in HB tissues and cells was detected by RT-qPCR. Western blotting was used to explore the protein expression of CCK18- and PI3K/AKT-related proteins.

Results

The expression of CCL18 in HB tissues and cells was overexpressed compared with control groups. CCL18 knockdown was found to notably block cell proliferation and progression, while enhancing cell apoptosis in HuH-6 and HepT1 cells. Furthermore, propofol suppressed the proliferation of HB cells in a dose-dependent manner. According to the results, we chose 5 μg/mL of propofol-treated cells for 48 hours as the subsequent experimental conditions. We found that propofol (5 μg/mL, 48 h) significantly blocked cell migration and invasion, but induced cell apoptosis in HuH-6 and HepT1 cells. In addition, CCK18 overexpression facilitated cell progression in HB cells, while propofol dramatically suppressed the effect of CCK18. Besides that, propofol suppressed the PI3K/AKT pathway.

Conclusion

Propofol suppressed the development of HB cells by inhibiting CCK18 expression and the PI3K/AKT pathway. Therefore, we infer that propofol plays a role in the treatment of HB.

Remimazolam: Non-Clinical and Clinical Profile of a New Sedative/Anesthetic Agent

A program to identify novel intravenous sedatives with a short and predictable duration of action was initiated in the late 1990's by Glaxo Wellcome. The program focussed on the identification of ester-based benzodiazepine derivatives that are rapidly broken down by esterases. Remimazolam was identified as one of the lead compounds. The project at Glaxo was shelved for strategic reasons at the late lead optimization stage. Via the GSK ventures initiative, the program was acquired by the small biotechnology company, TheraSci, and, through successive acquisitions, developed as the besylate salt at CeNeS and PAION. The development of remimazolam besylate has been slow by industry standards, primarily because of the resource limitations of these small companies. It has, however, recently been approved for anesthesia in Japan and South Korea, procedural sedation in the United States, China, and Europe, and for compassionate use in intensive care unit sedation in Belgium. A second development program of remimazolam was later initiated in China, using a slightly different salt form, remimazolam tosylate. This salt form of the compound has also recently been approved for procedural sedation in China. Remimazolam has the pharmacological profile of a classical benzodiazepine, such as midazolam, but is differentiated from other intravenous benzodiazepines by its rapid conversion to an inactive metabolite resulting in a short onset/offset profile. It is differentiated from other intravenous hypnotic agents, such as propofol, by its low liability for cardiovascular depression, respiratory depression, and injection pain. The benzodiazepine antagonist flumazenil can reverse the effects of remimazolam in case of adverse events and further shorten recovery times. The aim of this review is to provide an analysis of, and perspective on, published non-clinical and clinical information on 1) the pharmacology, metabolism, pharmacokinetics, and pharmacodynamic profile of remimazolam, 2) the profile of remimazolam compared with established agents, 3) gaps in the current understanding of remimazolam, 4) the compound's discovery and development process and 5) likely future developments in the clinical use of remimazolam.

Prospective, randomized comparison of two supplemental oxygen methods during gastroscopy with propofol mono-sedation in obese patients. World J Clin Cases 2021;9:5479-5489. [PMID: 34307602 PMCID: PMC8281412 DOI: 10.12998/wjcc.v9.i20.5479]

BACKGROUND

Hypoxemia is a common complication in obese patients during gastroscopy with sedation. The Wei nasal jet tube (WNJT) is a new special nasopharyngeal airway with the ability to provide supraglottic jet ventilation and oxygen insufflation via its built-in wall channels. The aim of this study was to compare the efficacy and safety of the WNJT vs a nasal cannula for supplemental oxygen during gastroscopy with propofol mono-sedation in obese patients.

AIM

To compare the efficacy and safety of the WNJT vs a nasal cannula for supplemental oxygen during gastroscopy with propofol mono-sedation in obese patients.

METHODS

A total of 103 obese patients with a body mass index of 30 kg/m² or more undergoing elective gastroscopy under propofol mono-sedation were randomly assigned to receive supplemental oxygen at 5 L/min through either a WNJT (WNJT group, n = 51) or a nasal cannula (nasal cannula group, n = 52). The lowest pulse oxygen saturation (SpO₂) and mild and severe hypoxemia during gastroscopy were recorded. The primary outcome was the incidence of hypoxemia.

RESULTS

The lowest SpO₂ during gastroscopy with propofol mono-sedation was significantly increased in the WNJT group compared with the nasal cannula group. The incidence of mild hypoxemia and total incidence of hypoxemia were significantly lower in the WNJT group than in the nasal cannula group. Other than a higher incidence of epistaxis in the WNJT group, the occurrence of adverse events was similar between the devices. While neither device demonstrated a statistically significant difference in satisfaction among patients, the WNJT did result in improved satisfaction among anesthetists and physicians.

CONCLUSION

During gastroscopy with propofol mono-sedation in obese patients, the WNJT, when compared with a nasal cannula for supplemental oxygen, can significantly reduce the occurrence of hypoxemia and improve both arterial oxygenation and satisfaction among anesthetists and physicians. The use of the WNJT may, however, lead to epistaxis in a few patients. In view of this clinically acceptable risk-benefit ratio, the WNJT may be recommended as an alternative tool for supplemental oxygen for the prevention of hypoxemia during gastroscopy with propofol mono-sedation in obese patients.

LncRNA DiGeorge syndrome critical region gene 5: A crucial regulator in malignant tumors

Long non-coding RNA (lncRNA), a subgroup of ncRNA with a length of more than 200 nt without protein coding function, has been recognized by the academia for its mediating effects of dysregulated expression on the tumorigenesis and development of a variety of tumors. LncRNA DiGeorge syndrome critical region gene 5 (DGCR5), originally found to induce DiGeorge syndrome, has been confirmed to be extremely dysregulated in multiple tumors, which mediates the malignant phenotypes of hepatocellular carcinoma, pancreatic cancer, lung cancer, etc. through the regulation of Wnt/β-catenin, MEK/ERK1/2 and other cancerous signaling pathways as a molecular sponge. Researches on the cancerous derivation-related pathways involved in DGCR5 can provide potential molecular intervention targets for tumor precision treatment. Moreover, liquid biopsy based on the detection of DGCR5 in body fluids is also expected to provide a non-invasive evaluation method for the early diagnosis and prognostic evaluation of malignant tumors.

Propofol detection for monitoring of intravenous anaesthesia: a review

This paper presents a review of established and emerging methods for detecting and quantifying the intravenous anaesthetic propofol in solution. There is growing evidence of numerous advantages of total intravenous anaesthesia using propofol compared to conventional volatile-based anaesthesia, both in terms of patient outcomes and environmental impact. However, volatile-based anaesthesia still accounts for the vast majority of administered general anaesthetics, largely due to a lack of techniques for real-time monitoring of patient blood propofol concentration. Herein, propofol detection techniques that have been developed to date are reviewed alongside a discussion of remaining challenges.

Inhibition of human UDP-glucuronosyltransferase enzyme by Dabrafenib: Implications for drug-drug interactions

Dabrafenib is a novel small molecule tyrosine kinase inhibitor (TKI) which is used to treat metastatic melanoma. The aim of this research was to survey the effects of dabrafenib on human UDP-glucuronosyltransferases (UGTs) and to evaluate the risk of drug-drug interactions (DDIs). The formation rates for 4-methylumbelliferone (4-MU) glucuronide and trifluoperazine-glucuronide in 12 recombinant human UGT isoforms with or without dabrafenib were measured and HPLC was used to investigate the inhibitory effects of dabrafenib on UGTs. Inhibition kinetic studies were also conducted. In vitro-in vivo extrapolation approaches were further used to predict the risk of DDI potentials of dabrafenib via inhibition of UGTs. Our data indicated that dabrafenib had a broad inhibitory effect on 4-MU glucuronidation by inhibiting the activities of UGTs, especially on UGT1A1, UGT1A7, UGT1A8, and UGT1A9, and dabrafenib could increase the area under the curve of co-administered drugs. Dabrafenib is a strong inhibitor of several UGTs and the co-administration of dabrafenib with drugs primarily metabolized by UGT1A1, 1A7, 1A8 or 1A9 may induce potential DDIs.

Case Report: Pink Urine Syndrome Following Exposure to Propofol: A Rare, Impressive but Benign Complication

Drug-induced changes in urine color induced by drugs may have clinical significance. Pink urine syndrome (PUS), which has been associated with urinary uric acid (UA) disorders, is most frequently reported in patients with morbid obesity undergoing gastric bypass surgery and/or from propofol anesthesia use in those who potentially have preexisting UA metabolism disorders. However, PUS has rarely occurred following exposure to propofol in non-obese patients, and literature on long-term follow-up after PUS is scarce. We report a case of PUS induced by propofol in a previously healthy non-obese woman after undergoing thoracoscopic wedge resection of pulmonary nodules under general anesthesia using propofol. The patient suddenly developed pink urine 4 h after surgery. A pink sediment rapidly precipitated at the bottom of the test tube following centrifugation of the urine. Amorphous, colorless UA-like crystals were identified under a polarizing microscope. The diagnosis of PUS was confirmed by examining the urinary UA concentration. The patient recovered and as followed-up for 1 month, during which she did not experience any urinary complications. To our knowledge, this is the first report to describe in detail a case of PUS caused by propofol in a non-obese patient with follow-up. PUS is usually benign and can resolve by rapidly on administering lactated Ringer’s solution; however, the potential risk of urinary complications, particularly UA lithiasis, should be fully realized.

Baclofen therapeutics, toxicity, and withdrawal: A narrative review

Baclofen is an effective therapeutic for the treatment of spasticity related to multiple sclerosis, spinal cord injuries, and other spinal cord pathologies. It has been increasingly used off-label for the management of several disorders, including musculoskeletal pain, gastroesophageal reflux disease, and alcohol use disorder. Baclofen therapy is associated with potential complications, including life-threatening toxicity and withdrawal syndrome. These disorders require prompt recognition and a high index of suspicion. While these complications can develop following administration of either oral or intrathecal baclofen, the risk is greater with the intrathecal route. The management of baclofen toxicity is largely supportive while baclofen withdrawal syndrome is most effectively treated with re-initiation or supplementation of baclofen dosing. Administration of other pharmacologic adjuncts may be required to effectively treat associated withdrawal symptoms. This narrative review provides an overview of the historical and emerging uses of baclofen, offers practical dosing recommendations for both oral and intrathecal routes of administration, and reviews the diagnosis and management of both baclofen toxicity and withdrawal.

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) 100 μg kg^-1 administered exactly 1 minute following propofol (AstraZeneca) 2 mg kg^-1 . In 20 male 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 (C_p ) at loss-of-behavioral response (LOBR) using bispectral index (BIS); cisatracurium onset time, lag time, and C_p 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 C_p at LOBR was 33.60% lower than men and cisatracurium C_p 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 C_p at LOBR and cisatracurium C_p 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.

Evaluation of anaesthetic depth and cardiopulmonary effects of propofol infusion rate in Sapajus apella previously chemically contained with dextroketamine-midazolam

BACKGROUND

This study evaluated the cardiopulmonary effects and anaesthetic depth induced by a propofol infusion rate of 0.8 mg/kg/min in monkeys (Sapajus apella).

MATERIALS AND METHODS

Five capuchin monkeys received dextroketamine-midazolam intramuscularly. After a maximum duration of 5 min, the values of the physiological parameters were recorded, and a venous catheter was placed. After recovery from chemical restraint, the animals were anaesthetized with propofol intravenously, which was maintained for 1 h. Physiological parameters, anaesthetic depth, the time and quality of anaesthetic recovery were evaluated.

RESULTS

Heart and respiratory rates, systolic blood pressure and rectal temperature during propofol infusion were lower than those during anaesthesia induction with dextroketamine-midazolam. Unconsciousness, muscle relaxation and lack of response to tail clamping were observed during propofol infusion. No animals showed excitement or vocalization during anaesthetic recovery.

CONCLUSION

Propofol infusion rate of 0.8 mg/kg/min promoted surgical general anaesthesia, with transient hypotension, which showed excellent anaesthetic recovery.

Correlation of exhaled propofol with Narcotrend index and calculated propofol plasma levels in children undergoing surgery under total intravenous anesthesia - an observational study

BACKGROUND

Exhaled propofol concentrations correlate with propofol concentrations in adult human blood and the brain tissue of rats, as well as with electroencephalography (EEG) based indices of anesthetic depth. The pharmacokinetics of propofol are however different in children compared to adults. The value of exhaled propofol measurements in pediatric anesthesia has not yet been investigated. Breathing system filters and breathing circuits can also interfere with the measurements. In this study, we investigated correlations between exhaled propofol (exP) concentrations and the Narkotrend Index (NI) as well as calculated propofol plasma concentrations.

METHODS

A multi-capillary-column (MCC) combined with ion mobility spectrometry (IMS) was used to determine exP. Optimal positioning of breathing system filters (near-patient or patient-distant) and sample line (proximal or distal to filter) were investigated. Measurements were taken during induction (I), maintenance (M) and emergence (E) of children under total intravenous anesthesia (TIVA). Correlations between ExP concentrations and NI and predicted plasma propofol concentrations (using pediatric pharmacokinetic models Kataria and Paedfusor) were assessed using Pearson correlation and regression analysis.

RESULTS

Near-patient positioning of breathing system filters led to continuously rising exP values when exP was measured proximal to the filters, and lower concentrations when exP was measured distal to the filters. The breathing system filters were therefore subsequently attached between the breathing system tubes and the inspiratory and expiratory limbs of the anesthetic machine. ExP concentrations significantly correlated with NI and propofol concentrations predicted by pharmacokinetic models during induction and maintenance of anesthesia. During emergence, exP significantly correlated with predicted propofol concentrations, but not with NI.

CONCLUSION

In this study, we demonstrated that exP correlates with calculated propofol concentrations and NI during induction and maintenance in pediatric patients. However, the correlations are highly variable and there are substantial obstacles: Without patient proximal placement of filters, the breathing circuit tubing must be changed after each patient, and furthermore, during ventilation, a considerable additional loss of heat and moisture can occur. Adhesion of propofol to plastic parts (endotracheal tube, breathing circle) may especially be problematic during emergence.

TRIAL REGISTRATION

The study was registered in the German registry of clinical studies (DRKS-ID:  DRKS00015795 ).

The effects of remifentanil combined with propofol on the oxidative damage and the stress and inflammatory responses in cardiac surgery patients

OBJECTIVE

This paper aims to explore the effects of remifentanil combined with propofol on the stress responses, oxidative damage, and inflammatory responses in cardiac surgery patients.

METHODS

One hundred and four patients who underwent cardiac surgery in our hospital from August 2017 to March 2019, were recruited as the study cohort and divided into control and observation groups. The 50 patients in the control group were anesthetized with fentanyl and propofol, and the 54 patients in the observation group were anesthetized with remifentanil and propofol. The general clinical data were observed and compared between the two groups. At different time points, changes in the oxidative stress response indicators (mean artery pressure (MAP) and heart rate (HR)) and in the cardiac function indexes (left ventricular ejection fraction (LVEF), stroke volume (SV), and cardiac output (CO)) were observed. The inflammatory cytokine levels (high-sensitivity C-reactive protein (hs-CRP), interleukin-10 (IL-10), and tumor necrosis factor-α (TNF-α)) were analyzed using enzyme-linked immunosorbent assays (ELISA). The patients' postoperative recovery (time to spontaneous respiration, time to opening eyes, extubation time) and their Visual Analogue Scale (VAS) scores were observed. Their pain at half an hour and at 24 hours after the operation were observed, as well as their postoperative adverse reactions.

RESULTS

There were no differences in the general data between the two groups (P>0.05). Compared with the patients in the control group, the patients in the observation group had better oxidative stress levels and better cardiac function indexes (P<0.05), better postoperative inflammatory cytokine levels (P<0.05), better postoperative recovery (P<0.05), lower postoperative pain scores (P<0.05), and a lower total incidence of adverse reactions (P<0.05).

CONCLUSION

Remifentanil combined with propofol can effectively reduce oxidative stress and inflammatory responses in cardiac surgery patients.

Current status of perioperative hypnotics, role of benzodiazepines, and the case for remimazolam: a narrative review

Anaesthesiologists and non-anaesthesiologist sedationists have a limited set of available i.v. hypnotics, further reduced by the withdrawal of thiopental in the USA and its near disappearance in Europe. Meanwhile, demand for sedation increases and new clinical groups are using what traditionally are anaesthesiologists' drugs. Improved understanding of the determinants of perioperative morbidity and mortality has spotlighted hypotension as a potent cause of patient harm, and practice must be adjusted to respect this. High-dose propofol sedation may be harmful, and a critical reappraisal of drug choices and doses is needed. The development of remimazolam, initially for procedural sedation, allows reconsideration of benzodiazepines as the hypnotic component of a general anaesthetic even if their characterisation as i.v. anaesthetics is questionable. Early data suggest that a combination of remimazolam and remifentanil can induce and maintain anaesthesia. Further work is needed to define use cases for this technique and to determine the impact on patient outcomes.

Current State of Analgesia and Sedation in the Pediatric Intensive Care Unit

Critically ill pediatric patients often require complex medical procedures as well as invasive testing and monitoring which tend to be painful and anxiety-provoking, necessitating the provision of analgesia and sedation to reduce stress response. Achieving the optimal combination of adequate analgesia and appropriate sedation can be quite challenging in a patient population with a wide spectrum of ages, sizes, and developmental stages. The added complexities of critical illness in the pediatric population such as evolving pathophysiology, impaired organ function, as well as altered pharmacodynamics and pharmacokinetics must be considered. Undersedation leaves patients at risk of physical and psychological stress which may have significant long term consequences. Oversedation, on the other hand, leaves the patient at risk of needing prolonged respiratory, specifically mechanical ventilator, support, prolonged ICU stay and hospital admission, and higher risk of untoward effects of analgosedative agents. Both undersedation and oversedation put critically ill pediatric patients at high risk of developing PICU-acquired complications (PACs) like delirium, withdrawal syndrome, neuromuscular atrophy and weakness, post-traumatic stress disorder, and poor rehabilitation. Optimal analgesia and sedation is dependent on continuous patient assessment with appropriately validated tools that help guide the titration of analgosedative agents to effect. Bundled interventions that emphasize minimizing benzodiazepines, screening for delirium frequently, avoiding physical and chemical restraints thereby allowing for greater mobility, and promoting adequate and proper sleep will disrupt the PICU culture of immobility and reduce the incidence of PACs.

Effects of anesthetic agents on inflammation in Caco-2, HK-2 and HepG2 cells

Anesthetic agents are often used in surgical procedures to relieve pain in patients with traumatic injuries. Several anesthetic agents can cause immunosuppression by suppressing the secretion of immune factors such as cytokines. However, the effects of different anesthetic agents on inflammation are not completely understood. In the present study, three cell lines, Caco-2, HK-2 and HepG2, were treated with five anesthetic agents, including sodium barbiturate, midazolam, etomidate, ketamine and propofol, to investigate the effects of different anesthetic agents on inflammation in in vitro models. The expression levels of inflammatory genes, including NF-κB and its downstream cytokines, were detected via reverse transcription-quantitative PCR. The results indicated that anesthetic agents, including sodium barbiturate, ketamine and propofol, but not midazolam and etomidate, exerted significant inhibitory effects on NF-κB expression in the three different cell lines. Sodium barbiturate, ketamine and propofol also decreased the expression levels of the NF-κB downstream cytokines, including IL-1β and IL-18. Moreover, sodium barbiturate, ketamine and propofol reduced the effect of TNF-α on inflammatory activity in the three cell lines. The results of the present study may provide novel insight into the effects of anesthetic agents on inflammation and may aid with selecting the most appropriate anesthetic agent in surgical procedures.

Influence of anesthetic induction of propofol combined with esketamine on perioperative stress and inflammatory responses and postoperative cognition of elderly surgical patients

OBJECTIVE

To analyze the influence of anesthetic induction of propofol combined with esketamine on perioperative stress and inflammatory responses and postoperative cognition in elderly surgical patients.

METHODS

A total of 80 elderly surgical patients were randomly divided into a control group (n=40) and a study group (n=40). The control group received anesthetic induction with propofol combined with sufentanil, while the study group received anesthetic induction with propofol combined with esketamine. Hemodynamics, stress and inflammatory responses and changes in cognitive function, perioperative related indexes and adverse responses were compared between the two groups.

RESULTS

At T₁, the levels of adrenaline, norepinephrine, endothelin, C-reactive protein, white blood cell and procalcitonin in the two groups were not markedly changed compared with those at T₀. The levels of the indices at T₂ and T₃ were elevated compared with those at T₁. However, the levels of the indices at T₄ were almost close to those at T₀, and the levels in the study group were higher than those in the control group. There were statistically significant differences in the comparison of the interaction of the levels of the aforementioned indices between groups, between time points, and between groups and time points (P < 0.05). At 24 h after surgery, the Montreal Cognitive Assessment (MoCA) scores were decreased in both groups, and the MoCA scores in the study group were higher than those in the control group (P < 0.05). The anesthesia time and consciousness recovery time in the study group were shorter than those in the control group (P < 0.05).

CONCLUSION

The anesthetic induction of propofol combined with esketamine, exhibits a good safety profile and reliability, it can improve hemodynamics and surgical stress and inflammatory responses, shorten anesthesia time, promote the recovery of postoperative cognitive function, and cause relatively mild adverse responses.

Effects of propofol on cardiac function and miR-494 expression in rats with hepatic ischemia/reperfusion injury

OBJECTIVE

This study aimed to investigate the effects of propofol on cardiac function and miR-494 expression in rats with hepatic ischemia/reperfusion (I/R) injury.

METHODS

Forty healthy adult male Sprague-Dawley rats were allocated to the sham operation group and three hepatic I/R injury groups. The I/R injury groups included I/R injury only (I/R group), treatment with propofol (propofol group), and treatment with propofol + overexpressed miR-494 (propofol+miR-494 group). Apoptosis of myocardial cells and changes in cardiac function indices, including left ventricular end-diastolic diameter, left ventricular end-systolic diameter, and left ventricular posterior wall thickness, as well as changes in miR-494, were monitored.

RESULTS

The apoptotic rate of myocardial cells in the I/R group was higher, cardiac function was deteriorated, and miR-494 levels were elevated compared with the sham group. The apoptotic rate was lower, cardiac function was improved, and miR-494 levels were suppressed in the propofol group compared with the I/R group. The apoptotic rate was higher, cardiac function was deteriorated, and miR-494 levels were elevated in the propofol+miR-494 group compared with the propofol group.

CONCLUSION

Propofol plays a vital role in preventing myocardial cell apoptosis and improvement of cardiac function by suppressing miR-494 in a hepatic I/R injury rat model.

Challenges in Sedation Management in Critically Ill Patients with COVID-19: a Brief Review

Purpose of Review

To highlight the challenges associated with providing sedation and analgesia to critically ill patients with coronavirus disease 2019 (COVID-19) and also understand the pathophysiological alterations induced by the disease process as well as the logistical difficulties encountered by providers caring for these patients. We also discuss the rationale and risks associated with the use of common sedative agents specifically within the context of COVID-19 and provide evidence-based management strategies to help manage sedation and analgesia in such patients.

Recent Findings

A significant proportion of patients with COVID-19 require intensive care and mechanical ventilation, thus requiring sedation and analgesia. These patients tend to require higher doses of sedative medications and often for long periods of time. Most of the commonly used sedative and analgesic agents carry unique risks that should be considered within the context of the unique pathophysiology of COVID-19, the logistical issues the disease poses, and the ongoing drug shortages.

Summary

With little attention being paid to sedation practices specific to patients with COVID-19 in critical care literature and minimal mention in national guidelines, there is a significant gap in knowledge. We review the existing literature to discuss the unique challenges that providers face while providing sedation and analgesia to critically ill patients with COVID-19 and propose evidence-based management strategies.

Guidelines for accreditation of endoscopy units: quality measures from the Korean Society of Coloproctology

Purpose

Colonoscopy is an effective method of screening for colorectal cancer (CRC), and it can prevent CRC by detection and removal of precancerous lesions. The most important considerations when performing colonoscopy screening are the safety and satisfaction of the patient and the diagnostic accuracy. Accordingly, the Korean Society of Coloproctology (KSCP) herein proposes an optimal level of standard performance to be used in endoscopy units and by individual colonoscopists for screening colonoscopy. These guidelines establish specific criteria for assessment of safety and quality in screening colonoscopy.

Methods

The Colonoscopy Committee of the KSCP commissioned this Position Statement. Expert gastrointestinal surgeons representing the KSCP reviewed the published evidence to identify acceptable quality indicators and indicators that lacked sufficient evidence.

Results

The KSCP recommends an optimal standard list for quality control of screening colonoscopy in the following 6 categories: training and competency of the colonoscopist, procedural quality, facilities and equipment, performance indicators and auditable outcomes, disinfection of equipment, and sedation and recovery of the patient.

Conclusion

The KSCP recommends that endoscopy units performing CRC screening evaluate 6 key performance measures during daily practice.

Neurocognitive Impairment After Propofol With Relevance for Neurosurgical Patients and Awake Craniotomies-A Prospective Observational Study

Background: Short-acting anesthetics are used for rapid recovery, especially for neurological testing during awake craniotomy. Extent and duration of neurocognitive impairment are ambiguous.

Methods: Prospective evaluation of patients undergoing craniotomy for tumor resection during general anesthesia with propofol (N of craniotomies = 35). Lexical word fluency, digit span and trail making were tested preoperatively and up to 24 h after extubation. Results were stratified for age, tumor localization and hemisphere of surgery. Results in digit span test were compared to 21 patients during awake craniotomies.

Results: Word fluency was reduced to 30, 33, 47, and 87% of preoperative values 10, 30, 60 min and 24 h after extubation, respectively. Digit span was decreased to 41, 47, 55, and 86%. Performances were still significantly impaired 24 h after extubation, especially in elderly. Results of digit span test were not worse in patients with left hemisphere surgery. Significance of difference to baseline remained, when patients with left or frontal lesions, i.e., brain areas essential for these tests, were excluded from analysis. Time for trail making was increased by 87% at 1 h after extubation, and recovered within 24 h. In 21 patients undergoing awake craniotomies without pharmacological sedation, digit span was unaffected during intraoperative testing.

Conclusion: Selected aspects of higher cognitive functions are compromised for up to 24 h after propofol anesthesia for craniotomy. Propofol and the direct effects of surgical resection on brain networks may be two major factors contributing (possibly jointly) to the observed deficits. Neurocognitive testing was unimpaired in patients undergoing awake craniotomies without sedation.

Understanding the Effects of Anesthesia on Cortical Electrophysiological Recordings: A Scoping Review

General anesthesia in animal experiments is an ethical must and is required for all the procedures that are likely to cause more than slight or momentary pain. As anesthetics are known to deeply affect experimental findings, including electrophysiological recordings of brain activity, understanding their mechanism of action is of paramount importance. It is widely recognized that the depth and type of anesthesia introduce significant bias in electrophysiological measurements by affecting the shape of both spontaneous and evoked signals, e.g., modifying their latency and relative amplitude. Therefore, for a given experimental protocol, it is relevant to identify the appropriate anesthetic, to minimize the impact on neuronal circuits and related signals under investigation. This review focuses on the effect of different anesthetics on cortical electrical recordings, examining their molecular mechanisms of action, their influence on neuronal microcircuits and, consequently, their impact on cortical measurements.

The influence of depth of anesthesia and blood pressure on muscle recorded motor evoked potentials in spinal surgery. A prospective observational study protocol

For high-risk spinal surgeries, intraoperative neurophysiological monitoring (IONM) is used to detect and prevent intraoperative neurological injury. The motor tracts are monitored by recording and analyzing muscle transcranial electrical stimulation motor evoked potentials (mTc-MEPs). A mTc-MEP amplitude decrease of 50–80% is the most common warning criterion for possible neurological injury. However, these warning criteria often result in false positive warnings. False positives may be caused by inadequate depth of anesthesia and blood pressure on mTc-MEP amplitudes. The aim of this paper is to validate the study protocol in which the goal is to investigate the effects of depth of anesthesia (part 1) and blood pressure (part 2) on mTc-MEPs. Per part, 25 patients will be included. In order to investigate the effects of depth of anesthesia, a processed electroencephalogram (pEEG) monitor will be used. At pEEG values of 30, 40 and 50, mTc-MEP measurements will be performed. To examine the effect of blood pressure on mTc-MEPs the mean arterial pressure will be elevated from 60 to 100 mmHg during which mTc-MEP measurements will be performed. We hypothesize that by understanding the effects of depth of anesthesia and blood pressure on mTc-MEPs, the mTc-MEP monitoring can be interpreted more reliably. This may contribute to fewer false positive warnings. By performing this study after induction and prior to incision, this protocol provides a unique opportunity to study the effects of depths of anesthesia and blood pressure on mTc-MEPs alone with as little confounders as possible.

Trial registration number NL7772.

Exhaled Propofol Concentrations Correlate With Plasma and Brain Tissue Concentrations in Rats

BACKGROUND

Propofol can be measured in exhaled gas. Exhaled and plasma propofol concentrations correlate well, but the relationship with tissue concentrations remains unknown. We thus evaluated the relationship between exhaled, plasma, and various tissue propofol concentrations. Because the drug acts in the brain, we focused on the relationship between exhaled and brain tissue propofol concentrations.

METHODS

Thirty-six male Sprague-Dawley rats were anesthetized with propofol, ketamine, and rocuronium for 6 hours. Animals were randomly assigned to propofol infusions at 20, 40, or 60 mg·kg·h (n = 12 per group). Exhaled propofol concentrations were measured at 15-minute intervals by multicapillary column-ion mobility spectrometry. Arterial blood samples, 110 µL each, were collected 15, 30, and 45 minutes, and 1, 2, 4, and 6 hours after the propofol infusion started. Propofol concentrations were measured in brain, lung, liver, kidney, muscle, and fat tissue after 6 hours. The last exhaled and plasma concentrations were used for linear regression analyses with tissue concentrations.

RESULTS

The correlation of exhaled versus plasma concentrations (R = 0.71) was comparable to the correlation of exhaled versus brain tissue concentrations (R = 0.75) at the end of the study. In contrast, correlations between plasma and lung and between lung and exhaled propofol concentrations were poor. Less than a part-per-thousand of propofol was exhaled over 6 hours.

CONCLUSIONS

Exhaled propofol concentrations correlate reasonably well with brain tissue and plasma concentrations in rats, and may thus be useful to estimate anesthetic drug effect. The equilibration between plasma propofol and exhaled gas is apparently independent of lung tissue concentration. Only a tiny fraction of administered propofol is eliminated via the lungs, and exhaled quantities thus have negligible influence on plasma concentrations.

L-Carnitine and Acylcarnitines: Mitochondrial Biomarkers for Precision Medicine

Biomarker discovery and implementation are at the forefront of the precision medicine movement. Modern advances in the field of metabolomics afford the opportunity to readily identify new metabolite biomarkers across a wide array of disciplines. Many of the metabolites are derived from or directly reflective of mitochondrial metabolism. L-carnitine and acylcarnitines are established mitochondrial biomarkers used to screen neonates for a series of genetic disorders affecting fatty acid oxidation, known as the inborn errors of metabolism. However, L-carnitine and acylcarnitines are not routinely measured beyond this screening, despite the growing evidence that shows their clinical utility outside of these disorders. Measurements of the carnitine pool have been used to identify the disease and prognosticate mortality among disorders such as diabetes, sepsis, cancer, and heart failure, as well as identify subjects experiencing adverse drug reactions from various medications like valproic acid, clofazimine, zidovudine, cisplatin, propofol, and cyclosporine. The aim of this review is to collect and interpret the literature evidence supporting the clinical biomarker application of L-carnitine and acylcarnitines. Further study of these metabolites could ultimately provide mechanistic insights that guide therapeutic decisions and elucidate new pharmacologic targets.

Continuous monitoring of propofol in human serum with fouling compensation by support vector classifier

We present a new method for electrochemical sensing, which compensates the fouling effect of propofol through machine learning (ML) model. Direct and continuous monitoring of propofol is crucial in the development of automatic systems for control of drug infusion in anaesthesiology. The fouling effect on electrodes discourages the possibility of continuous online monitoring of propofol since polymerization of the surface produces sensor drift. Several approaches have been proposed to limit the phenomenon at the biochemical interface; instead, here, we present a novel ML-based calibration procedure. In this paper, we analyse a dataset of 600 samples acquired through staircase cyclic voltammetry (SCV), resembling the scenario of continuous monitoring of propofol, both in PBS and in undiluted human serum, to demonstrate that ML-based model solves electrode fouling of anaesthetics. The proposed calibration approach is based on Gaussian radial basis function support vector classifier (RBF-SVC) that achieves classification accuracy of 98.9% in PBS, and 100% in undiluted human serum. The results prove the ability of the ML-based model to correctly classify propofol concentration in the therapeutic range between 1μM and 60μM with levels of 10μM, continuously up to ten minutes, with one sample every 30s.

The anesthetist's choice of inhalational vs. intravenous anesthetics has no impact on survival of glioblastoma patients

Recent data suggest that the type of anesthesia used during the resection of solid tumors impacts the long-term survival of patients favoring total-intravenous-anesthesia (TIVA) over inhalative-anesthesia (INHA). Here we sought to query this impact on survival in patients undergoing resection of glioblastoma (GBM). All patients receiving elective resection of a newly diagnosed, isocitrate-dehydrogenase-1-(IDH1)-wildtype GBM under general anesthesia between January 2010 and June 2017 in the Department of Neurosurgery, Heidelberg University Hospital, were included. Patients were grouped according to the applied anesthetic technique. To adjust for potential prognostic confounders, patients were matched in a 1:2 ratio (TIVA vs. INHA), taking into account the known prognostic factors: age, extent of resection, O-6-methylguanine-DNA-methyltransferase-(MGMT)-promoter-methylation-status, pre-operative Karnofsky-performance-index and adjuvant radio- and chemotherapy. The primary endpoint was progression-free-survival (PFS) and the secondary endpoint was overall-survival (OS). In the study period, 576 patients underwent resection of a newly diagnosed, IDH-wildtype GBM. Patients with incomplete follow-up-data, on palliative treatment, having emergency or awake surgery; 54 patients remained in the TIVA-group and 417 in the INHA-group. After matching, 52 patients remained in the TIVA-group and 92 in the INHA-group. Median PFS was 6 months in both groups. The median OS was 13.5 months in the TIVA-group and 13.0 months in the INHA-group. No significant survival differences associated with the type of anesthesia were found either before or after adjustment for known prognostic factors. This retrospective study supports the notion that the current anesthetic approaches employed during the resection of IDH-wildtype GBM do not impact patient survival.

Effect of intravenous administration of lidocaine on the ED50 of propofol induction dose during gastroscopy in adult patients: A randomized, controlled study

WHAT IS KNOWN AND OBJECTIVE

Propofol provides a prominent sedation effect in gastroscopy. However, sedation with propofol alone during gastroscopy might result in circulatory and respiratory depression. This study aimed to test the hypothesis that the addition of intravenous lidocaine to propofol-based sedation could decrease the ED50 of propofol induction dose during gastroscopy in adult patients while the respiratory and haemodynamic stability were not compromised.

METHODS

Patients undergoing gastroscopy were randomly enrolled into lidocaine + propofol (L + P) group or normal saline + propofol (NS + P) group. Subjects were initially administered intravenous bolus of 1.5 mg/kg lidocaine in L + P group or equivalent volume of 0.9% saline in NS + P group. Anaesthesia was then induced with a single bolus of 1.0 μg sufentanil followed by injection of propofol in all patients. The induction dose of propofol for each individual patient was determined by the protocol of Dixon "up-and-down" method for both groups. The primary end point was the ED50 of propofol induction dose.

RESULTS

Totally, 48 patients were enrolled and completed this study. Compared with the NS + P group, the ED50 of propofol induction dose was significantly reduced in the L + P group (2.01 mg/kg vs. 1.69 mg/kg) (U = 61.5, p < 0.001).

WHAT IS NEW AND CONCLUSION

The addition of intravenous lidocaine significantly reduced the ED50 of propofol induction dose during gastroscopy in adult patients.

TRIAL REGISTRATION

The present clinical trial was registered at http://www.chictr.org.cn/ (registration No. ChiCTR1900024025, 23 June 2019).

A Co-Induction Technique Utilizing 4% Sevoflurane Followed by 0.75 mg/kg Propofol in Elderly Patients Undergoing Minimally Invasive Procedures: A Prospective Randomized Control Study

Background and Objectives: Elderly patients constitute a large segment of healthcare receivers. Considering the functional deterioration of multiple organ systems with aging, achieving a safe perioperative approach is challenging. Our aim is to study the safety and effectiveness of a genuinely regimented co-induction technique in order to minimize anesthesia-related complications. Materials and Methods: One hundred and five patients were assigned to three groups according to the induction technique: propofol, sevoflurane and co-induction group. Inclusion criteria: patients with age ≥65 and American Society of Anesthesiologists physical status classification (ASA) II-III who underwent endoscopic urological procedures. The propofol group received a dose of 1.5 mg kg⁻¹ of propofol over two minutes for induction. The sevoflurane group received 8% of sevoflurane and 100% oxygen through a plastic facemask with the fresh gas flow set at 8 L min⁻¹. The co-induction group received 4% sevoflurane through plastic facemask for two minutes, followed by a 0.75 mg kg⁻¹ dose of propofol. After ensuring full range jaw relaxation, the laryngeal mask airway (LMA) was inserted. Results: Overall, the co-induction technique had a favorable profile in terms of respiratory adverse events, while the sevoflurane group had a favorable profile in terms of hemodynamic stability. Furthermore, 24 (68.6%) patients receiving inhalational sevoflurane had episodes of transient apnea, which constitutes 77.4% of the 31 episodes of transient apnea in the studied sample (p < 0.001). Moreover, six (17.1%) patients in the sevoflurane group had an episode of partial laryngospasm (p = 0.034). Compared with the co-induction group, we found that the propofol group had significantly less systolic and diastolic blood pressures in the second minute, with p values of (0.018) and (0.015), respectively. Conclusions: The co-induction technique utilizing 4% sevoflurane at 8 L min⁻¹ flow of oxygen inhaled over two minutes followed by 0.75 mg kg⁻¹ of propofol achieved less respiratory adverse events compared with the sevoflurane group, and less hemodynamic instability compared with the propofol group.

Best practice & research clinical anesthesiology: Safety and quality in perioperative anesthesia care. Update on safety in pediatric anesthesia

Pediatric anesthesia is large part of anesthesia clinical practice. Children, parents and anesthesiologists fear anesthesia because of the risk of acute morbidity and mortality. Modern anesthesia in otherwise healthy children above 1 year of age in developed countries has become very safe due to recent advance in pharmacology, intensive education, and training as well as centralization of care. In contrast, anesthesia in these children in low-income countries is associated with a high risk of mortality due to lack of basic resources and adequate training of health care providers. Anesthesia for neonates and toddlers is associated with significant morbidity and mortality. Anesthesia-related (near) critical incidents occur in 5% of anesthetic procedures and are largely dependent on the skills and up-to-date knowledge of the whole perioperative team in the specific needs for children. An investment in continuous medical education of the perioperative staff is required and international standard operating protocols for common procedures and critical situations should be defined.

The influence of cardiac output on propofol and fentanyl pharmacokinetics and pharmacodynamics in patients undergoing abdominal aortic surgery

Cardiac output (CO) is expected to affect elimination and distribution of highly extracted and perfusion rate-limited drugs. This work was undertaken to quantify the effect of CO measured by the pulse pressure method on pharmacokinetics and pharmacodynamics of propofol and fentanyl administrated during total intravenous anesthesia (TIVA). The data were obtained from 22 ASA III patients undergoing abdominal aortic surgery. Propofol was administered via target-controlled infusion system (Diprifusor) and fentanyl was administered at a dose of 2-3 µg/kg each time analgesia appeared to be inadequate. Hemodynamic measurements as well as bispectral index were monitored and recorded throughout the surgery. Data analysis was performed by using a non-linear mixed-effect population modeling (NONMEM 7.4 software). Three compartment models that incorporated blood flows as parameters were used to describe propofol and fentanyl pharmacokinetics. The delay of the anesthetic effect, with respect to plasma concentrations, was described using a biophase (effect) compartment. The bispectral index was linked to the propofol and fentanyl effect site concentrations through a synergistic Emax model. An empirical linear model was used to describe CO changes observed during the surgery. Cardiac output was identified as an important predictor of propofol and fentanyl pharmacokinetics. Consequently, it affected the depth of anesthesia and the recovery time after propofol-fentanyl TIVA infusion cessation. The model predicted (not observed) CO values correlated best with measured responses. Patients' age was identified as a covariate affecting the rate of CO changes during the anesthesia leading to age-related difference in individual patient's responses to both drugs.

Membrane nanodomains homeostasis during propofol anesthesia as function of dosage and temperature

Some anesthetics bind and potentiate γ-aminobutyric-acid-type receptors, but no universal mechanism for general anesthesia is known. Furthermore, often encountered complications such as anesthesia induced amnesia are not understood. General anesthetics are hydrophobic molecules easily dissolving into lipid bilayers. Recently, it was shown that general anesthetics perturb phase separation in vesicles extracted from fixed cells. Unclear is whether under physiological conditions general anesthetics induce perturbation of the lipid bilayer, and whether this contributes to the transient loss of consciousness or anesthesia side effects. Here we show that propofol perturbs lipid nanodomains in the outer and inner leaflet of the plasma membrane in intact cells, affecting membrane nanodomains in a concentration dependent manner: 1 μM to 5 μM propofol destabilize nanodomains; however, propofol concentrations higher than 5 μM stabilize nanodomains with time. Stabilization occurs only at physiological temperature and in intact cells. This process requires ARP2/3 mediated actin nucleation and Myosin II activity. The rate of nanodomain stabilization is potentiated by GABA_A receptor activity. Our results show that active nanodomain homeostasis counteracts the initial disruption causing large changes in cortical actin. SIGNIFICANCE STATEMENT: General anesthesia is a routine medical procedure with few complications, yet a small number of patients experience side-effects that persist for weeks and months. Very young children are at risk for effects on brain development. Elderly patients often exhibit subsequent amnesia. Here, we show that the general anesthetic propofol perturbs the ultrastructure of the lipid bilayer of the cell membrane in intact cells. Initially propofol destabilized lipid nanodomains. However, with increasing incubation time and propofol concentration, the effect is reversed and nanodomains are further stabilized. We show that this stabilization is caused by the activation of the actin cortex under the membrane. These perturbations of membrane bilayer and cortical actin may explain how propofol affects neuronal plasticity at synapses.

Estimation of effective dose of propofol mono-sedation for successful insertion of upper gastrointestinal endoscope in healthy, non-obese Chinese adults

WHAT IS KNOWN AND OBJECTIVE

Propofol is effective in sedation for upper gastrointestinal (UGI) endoscopy. However, the optimum dose is ill-defined. This study aimed to estimate the effective dose of propofol mono-sedation for successful endoscope insertion in healthy, non-obese Chinese adults undergoing single UGI endoscopy.

METHODS

Twenty-six adult patients undergoing elective single UGI endoscopy were enrolled in this study. A modified Dixon's up-and-down method was utilized to assess the effective dose of propofol for successful endoscope insertion. The initial dose of propofol administered, 1.6 mg/kg, was adjusted with 0.1 mg/kg as a step size. The patient's responses to endoscope insertion were classified as either 'movement' or 'no movement'. When patient's responses were changed from 'movement' to 'no movement' or from 'no movement' to 'movement', a crossover was defined. After eight crossovers had been obtained, patient recruitment was stopped. The mean of midpoints of all crossovers obtained by the modified Dixon's up-and-down method in all 26 patients was defined as calculated median effective dose (ED₅₀ ) of propofol for successful endoscope insertion. Furthermore, probit regression analysis was used to determine the dose of propofol where 50% (ED₅₀ ) and 95% (ED₉₅ ) of endoscope insertion attempts were successful.

RESULTS

The calculated ED₅₀ of propofol for successful endoscope insertion was 1.89 ± 0.12 mg/kg. The probit regression analysis showed that ED₅₀ and ED₉₅ of propofol for successful endoscope insertion were 1.90 mg/kg (95% CI, 1.78-2.10 mg/kg) and 2.15 mg/kg (95% CI, 2.01-3.56 mg/kg), respectively. No any patient had hypoxaemia and gag reflex during the UGI endoscopy with propofol mono-sedation.

WHAT IS NEW AND CONCLUSION

In healthy, non-obese Chinese adults, propofol mono-sedation can provide excellent conditions of UGI endoscopy and the estimated ED₅₀ of propofol for successful endoscope insertion is 1.89 ± 0.12 mg/kg.

Population pharmacokinetics of propofol in neonates and infants: Gestational and postnatal age to determine clearance maturation

AIMS

Develop a population pharmacokinetic model describing propofol pharmacokinetics in (pre)term neonates and infants, that can be used for precision dosing (e.g. during target-controlled infusion) of propofol in this population.

METHODS

A nonlinear mixed effects pharmacokinetic analysis (Monolix 2018R2) was performed, based on a pooled study population in 107 (pre)term neonates and infants.

RESULTS

In total, 836 blood samples were collected from 66 (pre)term neonates and 41 infants originating from 3 studies. Body weight (BW) of the pooled study population was 3.050 (0.580-11.440) kg, postmenstrual age (PMA) was 36.56 (27.00-43.00) weeks and postnatal age (PNA) was 1.14 (0-104.00) weeks (median and min-max range). A 3-compartment structural model was identified and the effect of BW was modelled using fixed allometric exponents. Elimination clearance maturation was modelled accounting for the maturational effect on elimination clearance until birth (by gestational age [GA]) and postpartum (by PNA and GA). The extrapolated adult (70 kg) population propofol elimination clearance (1.64 L min^-1 , estimated relative standard error = 6.02%) is in line with estimates from previous population pharmacokinetic studies. Empirical scaling of BW on the central distribution volume in function of PNA improved the model fit.

CONCLUSIONS

It is recommended to describe elimination clearance maturation by GA and PNA instead of PMA on top of size effects when analyzing propofol pharmacokinetics in populations including preterm neonates. Changes in body composition in addition to weight changes or other physio-anatomical changes may explain the changes in central distribution volume. The developed model may serve as a prior for propofol dose finding and target-controlled infusion in (preterm) neonates.

Safety of conscious sedation in electroanatomical mapping procedures and cryoballoon pulmonary vein isolation

Immobilization of patients during electrophysiological procedures, to avoid complications by patients' unexpected bodily motion, is achieved by moderate to deep conscious sedation using benzodiazepines and propofol for sedation and opioids for analgesia. Our aim was to compare respiratory and hemodynamic safety endpoints of cryoballoon pulmonary vein isolation (PVI) and electroanatomical mapping (EAM) procedures. Included patients underwent either cryoballoon PVI or EAM procedures. Sedation monitoring included non-invasive blood pressure measurements, transcutaneous oxygen saturation (tSpO₂) and transcutaneous carbon-dioxide (tpCO₂) measurements. We enrolled 125 consecutive patients, 67 patients underwent cryoballoon atrial fibrillation ablation and 58 patients had an EAM and radiofrequency ablation procedure. Mean procedure duration of EAM procedures was significantly longer (p < 0.001) and propofol doses as well as morphine equivalent doses of administered opioids were significantly higher in EAM patients compared to cryoballoon patients (p < 0.001). Cryoballoon patients display higher tpCO₂ levels compared to EAM patients at 30 min (cryoballoon: 51.1 ± 7.0 mmHg vs. EAM: 48.6 ± 6.2 mmHg, p = 0.009) and at 60 min (cryoballoon: 51.4 ± 7.3 mmHg vs. EAM: 48.9 ± 6.6 mmHg, p = 0.07) procedure duration. Mean arterial pressure was significantly higher after 60 min (cryoballoon: 84.7 ± 16.7 mmHg vs. EAM: 76.7 ± 13.3 mmHg, p = 0.017) in cryoballoon PVI compared to EAM procedures. Regarding respiratory and hemodynamic safety endpoints, no significant difference was detected regarding hypercapnia, hypoxia and episodes of hypotension. Despite longer procedure duration and deeper sedation requirement, conscious sedation in EAM procedures appears to be as safe as conscious sedation in cryoballoon ablation procedures regarding hemodynamic and respiratory safety endpoints.

Status Epilepticus: Work-Up and Management in Adults

Status epilepticus is one of the most common neurological emergencies and is likely to have increasing prevalence in coming years given an aging "baby boomer" population in the United States. Because status epilepticus is associated with significant morbidity and mortality, identification and treatment are paramount. Care should be taken to exclude nonorganic mimics and infectious and metabolic causes. Status epilepticus can be classified into stages with associated recommendations for escalation in therapy, increasing from push-dose benzodiazepines to continuous anesthetic infusions and other nontraditional therapies. Concurrent electroencephalogram monitoring helps to identify, localize, and assess resolution of ictal patterns alongside antiseizure drug administration. A protocol is proposed for the management of status epilepticus in a step-wise fashion.

Remifentanil-based propofol-supplemented vs. balanced sevoflurane-sufentanil anesthesia regimens on bispectral index recovery after cardiac surgery: a randomized controlled study

Background

The present study was to compare the potential impact of remifentanil-based propofol-supplemented anesthesia regimen vs. conventional sevoflurane-sufentanil balanced anesthesia on postoperative recovery of consciousness indicated by bispectral index (BIS) values in patients undergoing cardiac surgery.

Methods

Patients undergoing cardiac surgery were randomly allocated to get the remifentanil-based propofol-supplemented anesthesia employing target-controlled infusion (TCI) of remifentanil and propofol (Group-PR, n = 15) or a balanced-anesthesia employing sevoflurane-inhalation and TCI-sufentanil (Group-C, n = 19). In Group-PR, plasma concentration (Cp) of TCI-remifentanil was fixed at 20 ng/ml, and the effect-site concentration of TCI-propofol was adjusted within 0.8–2.0 μg/ml to maintain BIS value of 40–60. In Group-C, sevoflurane dosage was adjusted within 1–1.5 minimum alveolar concentration to maintain BIS of 40–60, and Cp of TCI-sufentanil was fixed at 0.4 ng/ml. The inter-group difference in the time for achieving postoperative BIS > 80 (T-BIS80) in the intensive care unit was determined as the primary outcome. The inter-group difference in the extubation time was determined as the secondary outcome.

Results

T-BIS80, was shorter in Group-PR than Group-C (121.4 ± 64.9 min vs. 182.9 ± 85.1 min, respectively; the difference of means –61.5 min; 95% CI –115.7 to –7.4 min; effect size 0.812; P = 0.027). The extubation time was shorter in Group-PR than in Group-C (434.7 ± 131.3 min vs. 946.6 ± 393.3 min, respectively, P < 0.001).

Conclusions

Compared with the conventional sevoflurane-sufentanil balanced anesthesia, the remifentanil-based propofol-supplemented anesthesia showed significantly faster postoperative conscious recovery in patients undergoing cardiac surgery.

[Sensations of patients and their satisfaction during awake craniotomy]

Awake craniotomy (AC) has gained fantastic popularity over the past years. This approach is no longer the destiny of only highly specialized neurosurgical centers. Technical features of AC are completely developed. However, certain aspects of patients' sensations and their satisfaction are still unclear. The review is devoted to these issues. It was shown that AC is positively evaluated by the vast majority of patients. Many patients would choose this technique for redo surgery. However, there are certain important details that can adversely affect satisfaction of patients. Thus, these features should be considered in AC.

Population Pharmacokinetics of Caspofungin among Extracorporeal Membrane Oxygenation Patients during the Postoperative Period of Lung Transplantation

Little is known about the influence of extracorporeal membrane oxygenation (ECMO) on the pharmacokinetics (PK) of caspofungin. The aim of this study was to describe population PK of caspofungin in patients with and without ECMO during the postoperative period of lung transplantation (LTx) and to investigate covariates influencing caspofungin PK. We compared ECMO patients with non-ECMO patients, and patients before and after ECMO weaning as self-controls, to analyzed changes in caspofungin PK. Eight serial blood samples were collected from each patient for PK analysis. The population PK of caspofungin was described using nonlinear mixed-effects modeling. Twelve ECMO and 7 non-ECMO lung transplant recipients were enrolled in this study. None of the patients received renal replacement therapy during any part of the study period. The PK of caspofungin was best described by a two-compartment model. There were no significant differences in the PK parameters and concentrations of caspofungin among the ECMO, non-ECMO, and self-control group. In the final covariate model, we found that there was a significant association between the male gender and increased distribution volume, that a higher sequential organ failure assessment score was related to an increase in intercompartmental clearance, and that a longer operative time was related to an increase in clearance and the volume of distribution. ECMO did not have a significant impact on the PK of caspofungin in patients after LTx. Some factors were identified as statistically significant covariates related to the PK of caspofungin; however, their impact on clinical practice of caspofungin needs to be investigated further in more studies. (This study has been registered at ClinicalTrials.gov under identifier NCT03766282.).

System-Level Analysis of Closed-Loop Anesthesia Control Under Temporal Sensor Faults via UPPAAL-SMC

Hypnosis control is an essential process commonly used during medical surgeries and operations. In clinical practice, this process is achieved by an anesthesiologist who estimates the required dose for a patient and monitors the hypnotic status of the patient. For closed-loop sedation control systems to be approved for clinical practice, they have to demonstrate efficiency and robustness under parameter uncertainties and potential device faults. In this paper, new modeling and analysis of the closed-loop anesthesia administration are proposed using priced timed automata. The modeling involved the physiological system, the closed-loop controllers, and the fault scenario. The physiological model is based on a general model that accounts for parameter variability and residual errors from a broad group of data-sets. Two control techniques are analyzed: the proportional-integral-derivative controller and a variant of the sliding mode controller. The results have shown that the performance of both controllers was impacted by the sensor fault with the later one outperforming the former.Clinical relevance- The proposed in-silico methodology is used to estimate the performance degradation in closedloop anesthesia administration as a result of temporal faults. Moreover, it allows for evaluating different control techniques and help design reliable automatic control.

Effect of Patient State Index Monitoring on the Recovery Characteristics in Morbidly Obese Patients: Comparison of Inhalation Anesthesia and Total Intravenous Anesthesia

PURPOSE

Obese patients have a significantly higher risk of adverse effects associated with general anesthesia. The purpose of this study was to evaluate the effects of Patient State Index (PSI) monitoring on recovery from anesthesia and the incidence of any postoperative complications among patients undergoing bariatric surgery with total intravenous anesthesia (TIVA) and inhalational anesthesia.

DESIGN

This prospective, double-blind, and randomized controlled trial was conducted between February 2017 and August 2017 and included 120 morbidly obese patients (body mass index >40 kg/m²).

METHODS

Patients were randomly divided into four groups; group P-PSI (n = 30): TIVA with PSI monitoring; group P (n = 30): TIVA without PSI monitoring; group D-PSI (n = 30): desflurane with PSI monitoring; and group D (n = 30): desflurane without PSI monitoring. The discharge time from the postanesthesia care unit (PACU), postoperative complications, and hemodynamic parameters were recorded and evaluated.

FINDINGS

No significant differences were found in demographic data, duration of anesthesia, admittance to PACU, discharge from PACU, modified Aldrete scores, and perioperative mean blood pressure and heart rate. Nausea and vomiting scores were significantly lower in group P-PSI, group P, and group D-PSI compared with group D.

CONCLUSIONS

Although TIVA and inhalational anesthesia can be safely used for obese patients, intraoperative PSI monitoring may decrease the discharge time from PACU and reduces incidence of postoperative nausea and vomiting caused by inhalation anesthetics.

Role and Prognosis of Extracorporeal Life Support in Patients Who Develop Cardiac Arrest during or after Office-Based Cosmetic Surgery

Background

Cardiac arrest during or after office-based cosmetic surgery is rare, and little is known about its prognosis. We assessed the clinical outcomes of patients who developed cardiac arrest during or after cosmetic surgery at office-based clinics.

Methods

Between May 2009 and May 2016, 32 patients who developed cardiac arrest during or after treatment at cosmetic surgery clinics were consecutively enrolled. We compared clinical outcomes, including complications, between survivors (n=19) and non-survivors (n=13) and attempted to determine the prognostic factors of mortality.

Results

All 32 of the patients were female, with a mean age of 30.40±11.87 years. Of the 32 patients, 13 (41%) died. Extracorporeal life support (ECLS) was applied in a greater percentage of non-survivors than survivors (92.3% vs. 47.4%, respectively; p=0.009). The mean duration of in-hospital cardiopulmonary resuscitation (CPR) was longer for the non-survivors than the survivors (31.55±33 minutes vs. 7.59±9.07 minutes, respectively; p=0.01). The mean Acute Physiology and Chronic Health Evaluation score was also higher among non-survivors than survivors (23.85±6.68 vs. 16.79±7.44, respectively; p=0.01). No predictor of death was identified in the patients for whom ECLS was applied. Of the 19 survivors, 10 (52.6%) had hypoxic brain damage, and 1 (5.3%) had permanent lower leg ischemia. Logistic regression analyses revealed that the estimated glomerular filtration rate was a predictor of mortality.

Conclusion

Patients who developed cardiac arrest during or after cosmetic surgery at office-based clinics experienced poor prognoses, even though ECLS was applied in most cases. The survivors suffered serious complications. Careful monitoring of subjects and active CPR (when necessary) in cosmetic surgery clinics may be essential.

Influence of an "Electroencephalogram-Based" Monitor Choice on the Delay Between the Predicted Propofol Effect-Site Concentration and the Measured Drug Effect

BACKGROUND

Clinicians can optimize propofol titration by using 2 sources of pharmacodynamic (PD) information: the predicted effect-site concentration for propofol (Ceprop) and the electroencephalographically (EEG) measured drug effect. Relation between these sources should be time independent, that is, perfectly synchronized. In reality, various issues corrupt time independency, leading to asynchrony or, in other words, hysteresis. This asynchrony can lead to conflicting information, making effective drug dosing challenging. In this study, we tried to quantify and minimize the hysteresis between the Ceprop (calculated using the Schnider model for propofol) and EEG measured drug effect, using nonlinear mixed-effects modeling (NONMEM). Further, we measured the influence of EEG-based monitor choice, namely Bispectral index (BIS) versus qCON index (qCON) monitor, on propofol PD hysteresis.

METHODS

We analyzed the PD data from 165 patients undergoing propofol-remifentanil anesthesia for outpatient surgery. Drugs were administered using target-controlled infusion (TCI) pumps. Pumps were programmed with Schnider model for propofol and Minto model for remifentanil. We constructed 2 PD models (direct models) relating the Schnider Ceprop to the measured BIS and qCON monitor values. We quantified the models' misspecification due to hysteresis, on an individual level, using the root mean squared errors (RMSEs). Subsequently, we optimized the PD models' predictions by adding a lag term to both models (lag-time PD models) and quantified the optimization using the RMSE.

RESULTS

There is a counterclockwise hysteresis between Ceprop and BIS/qCON values. Not accounting for this hysteresis results in a direct PD model with an effect-site concentration which produces 50% of the maximal drug effect (Ce50) of 6.24 and 8.62 µg/mL and RMSE (median and interquartile range [IQR]) of 9.38 (7.92-11.23) and 8.41(7.04-10.2) for BIS and qCON, respectively. Adding a modeled lag factor of 49 seconds to the BIS model and 53 seconds to the qCON model improved both models' prediction, resulting in similar Ce50 (3.66 and 3.62 µg/mL for BIS and qCON) and lower RMSE (median (IQR) of 7.87 (6.49-9.90) and 6.56 (5.28-8.57) for BIS and qCON.

CONCLUSIONS

There is a significant "Ceprop versus EEG measured drug effect" hysteresis. Not accounting for it leads to conflicting PD information and false high Ce50 for propofol in both monitors. Adding a lag term improved the PD model performance, improved the "pump-monitor" synchrony, and made the estimates of Ce50 for propofol more realistic and less monitor dependent.

Cerebral autoregulation after aneurysmal subarachnoid haemorrhage. A preliminary study comparing dexmedetomidine to propofol and/or midazolam

BACKGROUND

Cerebral autoregulation is often impaired after aneurysmal subarachnoid haemorrhage (aSAH). Dexmedetomidine is being increasingly used, but its effects on cerebral autoregulation in patients with aSAH have not been studied before. Dexmedetomidine could be a useful sedative in patients with aSAH as it enables neurological assessment during the infusion. The aim of this preliminary study was to compare the effects of dexmedetomidine on dynamic and static cerebral autoregulation with propofol and/or midazolam in patients with aSAH.

METHODS

Ten patients were recruited. Dynamic and static cerebral autoregulation were assessed using transcranial Doppler ultrasound during propofol and/or midazolam infusion and then during three increasing doses of dexmedetomidine infusion (0.7, 1.0 and 1.4 μg/kg/h). Transient hyperaemic response ratio (THRR) and strength of autoregulation (SA) were calculated to assess dynamic cerebral autoregulation. Static rate of autoregulation (sRoR)% was calculated by using noradrenaline infusion to increase the mean arterial pressure 20 mm Hg above the baseline.

RESULTS

Data from nine patients were analysed. Compared to baseline, we found no statistically significant changes in THRR or sROR%. THRR was (mean ± SD) 1.20 ± 0.14, 1.17 ± 0.13 (P = .93), 1.14 ± 0.09 (P = .72) and 1.19 ± 0.18 (P = 1.0) and sROR% was 150.89 ± 84.37, 75.22 ± 27.75 (P = .08), 128.25 ± 58.35 (P = .84) and 104.82 ± 36.92 (P = .42) at baseline and during 0.7, 1.0 and 1.4 μg/kg/h dexmedetomidine infusion, respectively. Dynamic SA was significantly reduced after 1.0 μg/kg/h dexmedetomidine (P = .02).

CONCLUSIONS

Compared to propofol and/or midazolam, dexmedetomidine did not alter static cerebral autoregulation in aSAH patients, whereas a significant change was observed in dynamic SA. Further and larger studies with dexmedetomidine in aSAH patients are warranted.