Blood Propofol Concentrations Research Articles

Recovery of driving skills after endoscopy under propofol sedation: a prospective pilot study to assess the driving skills after endoscopic sedation using driving simulation

BackgroundPatients are recommended not to drive for at least the first 24 h after endoscopy with propofol sedation. However, the evidence underlying these recommendations is scarce. We hypothesized that after endoscopic procedures performed under propofol sedation, the subject’s driving ability was restored in less than 24 h.MethodsWe prospectively enrolled thirty patients between 20 and 70 years possessing a legitimate driver’s license scheduled for endoscopy at our hospital. The sample chosen was a convenience sample. Gastroscopy or colonoscopy was performed with propofol sedation. Before and after endoscopy, the investigator drove the subjects to the laboratory to assess their driving skills using a driving simulation system, which employs 3 driving scenarios designed by professional transportation researchers. The blood propofol concentration was estimated before endoscopy, and 2 and 4 h after endoscopy. The primary outcome was the time required for subjects to recover their driving ability after propofol sedation. The secondary outcome was the blood propofol concentration before and after endoscopic procedures under propofol anesthesia.ResultsThirty volunteers participated in the study and 18 of them completed all the interventions. In the low-risk S-curve scene, the mean acceleration, lane deviation, and number of deviations from the path at baseline (0.016 cm/s2, 42.50 cm, and 0.83, respectively) were significantly less than that at post-2 h (0.029 cm/s2, P = 0.001; 53.80 cm, P = 0.014; 2.06, P = 0.022). In the moderate-(overtaking) and high-risk (emergency collision avoidance) scenes, the tested parameters at baseline and post-2 h were statistically comparable. In the low-, moderate-, and high-risk scenes the tested parameters at baseline and post-4 h were statistically comparable. The total range of propofol was 120-280 mg.The mean blood concentration of propofol at post-2 h was 0.81 ± 0.40 µg/mL, and at post-4 h was below the limit of detection.ConclusionAfter endoscopy performed under propofol sedation, subjects’ driving abilities were completely restored at 4 h when tested on a simulator.

Selective Reagent Ion-Time-of-Flight-Mass Spectrometric Investigations of the Intravenous Anaesthetic Propofol and Its Major Metabolite 2,6-Diisopropyl-1,4-benzoquinone

The first detailed selected reagent ion-time-of-flight-mass spectrometric fundamental investigations of 2,6-diisopropylphenol, more commonly known as propofol (C12H18O), and its metabolite 2,6-diisopropyl-1,4-benzoquinone (C12H16O2) using the reagent ions H3O+, H3O+.H2O, O2+• and NO+ are reported. Protonated propofol is the dominant product ion resulting from the reaction of H3O+ with propofol up to a reduced electric field strength (E/N) of about 170 Td. After 170 Td, collision-induced dissociation leads to protonated 2-(1-methylethyl)-phenol (C9H13O+), resulting from the elimination of C3H6 from protonated propofol. A sequential loss of C3H6 from C9H13O+ also through collision-induced processes leads to protonated phenol (C6H7O+), which becomes the dominant ionic species at E/N values exceeding 170 Td. H3O+.H2O does not react with propofol via a proton transfer process. This is in agreement with our calculated proton affinity of propofol being 770 kJ mol−1. Both O2+• and NO+ react with propofol via a charge transfer process leading to two product ions, C12H18O+ (resulting from non-dissociative charge transfer) and C11H15O+ that results from the elimination of one of the methyl groups from C12H18O+. This dissociative pathway is more pronounced for O2+• than for NO+ throughout the E/N range investigated (approximately 60–210 Td), which reflects the higher recombination energy of O2+• (12.07 eV) compared to that of NO+ (9.3 eV), and hence the higher internal energy deposited into the singly charged propofol. Of the four reagent ions investigated, only H3O+ and H3O+.H2O react with 2,6-diisopropyl-1,4-benzoquinone, resulting in only the protonated parent at all E/N values investigated. The fundamental ion-molecule studies reported here provide underpinning information that is of use for the development of soft chemical ionisation mass spectrometric analytical techniques to monitor propofol and its major metabolite in the breath. The detection of propofol in breath has potential applications for determining propofol blood concentrations during surgery and for elucidating metabolic processes in real time.

Correlation of exhaled propofol with Narcotrend index and calculated propofol plasma levels in children undergoing surgery under total intravenous anesthesia -\xa0an observational study

BackgroundExhaled 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.MethodsA 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.ResultsNear-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.ConclusionIn 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 RegistrationThe study was registered in the German registry of clinical studies (DRKS-ID: DRKS00015795).

A "Smart" Biosensor-Enabled Intravascular Catheter and Platform for Dynamic Delivery of Propofol to "Close the Loop" for Total Intravenous Anesthesia.

Target-controlled infusion anesthesia is used worldwide to provide user-defined, stable, blood concentrations of propofol for sedation and anesthesia. The drug infusion is controlled by a microprocessor that uses population-based pharmacokinetic data and patient biometrics to estimate the required infusion rate to replace losses from the blood compartment due to drug distribution and metabolism. The objective of the research was to develop and validate a method to detect and quantify propofol levels in the blood, to improve the safety of propofol use, and to demonstrate a pathway for regulatory approval for its use in the USA. We conceptualized and prototyped a novel "smart" biosensor-enabled intravenous catheter capable of quantifying propofol at physiologic levels in the blood, in real time. The clinical embodiment of the platform is comprised of a "smart" biosensor-enabled catheter prototype, a signal generation/detection readout display, and a driving electronics software. The biosensor was validated in vitro using a variety of electrochemical methods in both static and flow systems with biofluids, including blood. We present data demonstrating the experimental detection and quantification of propofol at sub-micromolar concentrations using this biosensor and method. Detection of the drug is rapid and stable with negligible biofouling due to the sensor coating. It shows a linear correlation with mass spectroscopy methods. An intuitive graphical user interface was developed to: (1) detect and quantify the propofol sensor signal, (2) determine the difference between targeted and actual propofol concentration, (3) communicate the variance in real time, and (4) use the output of the controller to drive drug delivery from an in-line syringe pump. The automated delivery and maintenance of propofol levels was demonstrated in a modeled benchtop "patient" applying the known pharmacokinetics of the drug using published algorithms. We present a proof-of-concept and in vitro validation of accurate electrochemical quantification of propofol directly from the blood and the design and prototyping of a "smart," indwelling, biosensor-enabled catheter and demonstrate feedback hardware and software architecture permitting accurate measurement of propofol in blood in real time. The controller platform is shown to permit autonomous, "closed-loop" delivery of the drug and maintenance of user-defined propofol levels in a dynamic flow model.

Rapid quantitative determination of blood propofol concentration throughout perioperative period by negative photoionization ion mobility spectrometer with solvent-assisted neutral desorption

Rapid and quantitative determination of blood propofol concentration is important for anesthesiologists to accurately control intraoperative propofol dose, timely monitor physiological statuses of patients and greatly improve the safety of surgery. Herein, a dopant-assisted negative photoionization ion mobility spectrometer with the optimized ionization region structure and the three-way inlet design was developed, increasing the generation ratio of the reactant ions O2−, and improving the ionization efficiency of propofol molecules. Besides, the addition of methanol-anisole solution during injection promoted the neutral desorption of propofol in blood, further improving the detection sensitivity by an order of magnitude, eliminating any sample pretreatment and effectively reducing the single analysis time to less than 1 min compared to the previous article. The dual calibration quantitative method, i.e. the method of calibrating the O2− concentration and the sample concentration changes during the entire process of detecting propofol through the integral value of M·O2− and the maximum signal intensity of O2−, successfully achieved accurate quantification of blood propofol. And the linear calibration curve of propofol was obtained with the range of 0.1–15 ng μL−1 and with the limit of detection of 0.03 ng μL−1, which was fulfilled to conduct propofol determination throughout the perioperative period. Finally, this method was applied to clinically measure the blood propofol concentration in patients newly regained consciousness with concentrations ranging from 0.2 ng μL−1 to 3 ng μL−1, and it turned out that the older patient had the lower propofol concentration in blood.

Rapid determination and continuous monitoring of propofol in microliter whole blood sample during anesthesia by paper spray ionization-mass spectrometry.

Propofol is a widely used intravenous anesthetic agent in sedation and general anesthesia. To improve the safety and maintain the depth of anesthesia, it is important to develop a rapid, sensitive, and reliable method to monitor the concentration of propofol in blood during anesthesia continuously. Here, we present a novel strategy based on paper spray ionization-mass spectrometry (PSI-MS) to detect propofol. Samples (in 10μL) were mixed with methanol as protein precipitation solvent and 2,6-dimethylphenol as internal standard. Protein micro-precipitation was achieved with methanol by vortexing and centrifuging for 5s each, and propofol was extracted to the supernatant. PSI-MS was performed in negative ionization mode, and MS signal lasted for 1min. The analysis of a single sample was completed within 2min. The area ratios of propofol to internal standard were calculated for quantification. Limit of detection of 5.5ngmL-1 and limit of quantification of 18.2ngmL-1 were achieved for propofol in whole blood. Calibration curve was linear in the range of 0.02-10μgmL-1. The developed method was used successfully in monitoring the propofol concentration in 3 patients' whole blood during anesthesia, showing its further application in controlling and feeding-back target concentration infusion. Graphical abstract.

Evaluating Propofol Concentration in Blood From Exhaled Gas Using a Breathing-Related Partition Coefficient.

The anesthetic side effects of propofol still occur in clinical practice because no reliable monitoring techniques are available. In this regard, continuous monitoring of propofol in breath is a promising method, yet it remains infeasible because there is large variation in the blood/exhaled gas partial pressure ratio (RBE) in humans. Further evaluations of the influences of breathing-related factors on RBE would mitigate this variation. Correlations were analyzed between breathing-related factors (tidal volume [TV], breath frequency [BF], and minute ventilation [VM]) and RBE in 46 patients. Furthermore, a subset of 10 patients underwent pulmonary function tests (PFTs), and the parameters of the PFTs were then compared with the RBE. We employed a 1-phase exponential decay model to characterize the influence of VM on RBE. We also proposed a modified RBE (RBEM) that was not affected by the different breathing patterns of the patients. The blood concentration of propofol was predicted from breath monitoring using RBEM and RBE. We found a significant negative correlation (R = -0.572; P < .001) between VM and RBE (N = 46). No significant correlation was shown between PFTs and RBE in the subset (N = 10). RBEM demonstrated a standard Gaussian distribution (mean, 1.000; standard deviation [SD], 0.308). Moreover, the predicted propofol concentrations based on breath monitoring matched well with the measured blood concentrations. The 90% prediction band was limited to within ±1 μg·mL. The prediction of propofol concentration in blood was more accurate using RBEM than when using RBE and could provide reference information for anesthesiologists. Moreover, the present study provided a general approach for assessing the influence of relevant physiological factors and will inform noninvasive and accurate breath assessment of volatile drugs or metabolites in blood.

Propofol sedation with a target-controlled infusion pump in elderly patients undergoing ERCP

Advanced age is an important risk factor for adverse events (AEs) during propofol sedation for endoscopic procedures. This study aimed to evaluate the safety and efficacy of nonanesthesiologist-administered propofol (NAAP) sedation with a target-controlled infusion (TCI) system in elderly patients during ERCP. This study retrospectively analyzed 482 patients who underwent ERCP under propofol sedation with a TCI system at Iwakuni Medical Center between January 2014 and October 2016. Patients were divided into 3 groups according to their age: group A,<70 years (n= 130); group B,≥70 and<85 years (n= 224); and group C,≥85 years (n= 125). We compared the propofol dose and AEs during ERCP. The median total infusion dose and minimum and maximum target blood concentrations of propofol were 336 mg, 2.2 μg/mL, and 2.2 μg/mL in group A; 184 mg, 1.0 μg/mL, and 1.4 μg/mL in group B; and 99 mg, .6 μg/mL, and 1.0 μg/mL in group C, respectively, with older groups requiring a lower dose (P< .0001). Hypotension was observed in 23 patients (4.8%), with no significant difference between groups (group A, 2.3%; group B, 6.3%; group C, 4.8%; P= .24). Hypoxemia was observed in 16 patients (3.3%), with no significant difference between groups (group A, 3.1%; group B, 4.9%; group C, .8%; P= .17). All AEs were immediately resolved, and no procedures were aborted. NAAP sedation with a TCI system during ERCP may be acceptable in elderly patients with a lower dose of propofol than that used in younger patients.

Research progress on rapid detection of propofol

Propofol is a main representative of intravenous anesthetics, with the advantages of rapid onset, rapid awakening, and perfect function recovery. However, at present, there is no clinical method for monitoring its concentration in a real-time manner. Due to the disadvantages of traditional methods, such as complex sample pretreatment, long-time measurement, and large equipment in some assays which is unable to be placed in the operating room, increasing attention has been drawn towards rapid detection of propofol. The current paper is designed to comprehensively describe how to perform rapid detection of propofol concentrations. This article mainly discusses the rapid detection methods and principles of blood propofol concentrations and exhaled concentrations, so as to facilitate clinical application and to instruct anesthesiologists for evaluating anesthesia depth in a fast and real-time manner. Key words: Propofol; Drug concentration; Blood concentration; Expiratory gas; Rapid detection

Online monitoring of end-tidal propofol in balanced anesthesia by anisole assisted positive photoionization ion mobility spectrometer

Online measuring end-tidal propofol concentration during balanced anesthesia is important for anesthetists to learn the patient's anesthesia depth as exhaled propofol concentration is well related to blood propofol concentration. In previous work, exhaled propofol was detected using acetone assisted negative photoionization ion mobility spectrometer, however, the existence of high concentration sevoflurane interfered the response of propofol. In this work, an anisole assisted photoionization ion mobility spectrometer operated in positive mode was developed to sensitively and selectively measure the end-tidal propofol by eliminating the interferences of exhaled humidity and sevoflurane during balanced anesthesia. Anisole molecular ion is stable enough not to go under proton transfer reaction with water presents in the exhaled breath. Hence, the exhaled humidity related peaks were eliminated and only one propofol product ion peak (K0 = 1.50 cm2 V−1 s−1) was observed. The relative standard deviation (RSD) ranging from 0.64%–0.91% showed good repeatability and the quantitative range was 0.2–40 ppbv with a response time of 4 s. Finally, the performance of the proposed method was demonstrated by monitoring end-tidal propofol of balanced anesthetized patients during gastric cancer surgery.

Target-controlled propofol infusion with or without bispectral index monitoring of sedation during advanced gastrointestinal endoscopy.

Target-controlled infusion (TCI) uses averaged pharmacokinetic datasets derived from population samples to automatically control the infusion rate. Bispectral index (BIS) technology non-invasively measures levels of consciousness during surgical procedures. We compared the efficacy and safety of propofol TCI with or without BIS monitoring for sedation during advanced gastrointestinal endoscopy. This prospective study enrolled 200 patients who were premedicated with midazolam 2mg and alfentanil 0.4mg before undergoing advanced gastrointestinal endoscopy. The initial target blood concentration of propofol was set at 1.0μg/mL, and adjustments of 0.2μg/mL were made as necessary to maintain moderate-to-deep sedation. Patients were randomized to either the BIS-blind group and evaluated for depth of anesthesia by monitoring scores of 1-2 on the Modified Observer's Assessment of Alertness/Sedation scale (n=100) or to the BIS-open group and monitored by BIS scores of 60-80 (n=100). The primary outcome was the total amount of propofol required to maintain anesthesia. Secondary outcomes were sedation-induced adverse events, recovery, and quality of sedation (endoscopist and patient satisfaction). The mean propofol infusion rate was significantly higher in patients not monitored by BIS scores than in those who were (5.44±2.12 vs 4.76±1.84mg/kg/h; P=0.016). Levels of satisfaction were higher for endoscopists who used BIS monitoring than in those who did not. Mean infusion rates were higher in propofol TCI without BIS monitoring compared with propofol TCI with BIS during advanced gastrointestinal endoscopy. Endoscopists expressed satisfaction with BIS monitoring.

Rapid determination of intraoperative blood propofol concentration in operating theatre by dopant-enhanced neutral release and negative photoionization ion mobility spectrometry

The concentration of propofol in blood is an important indicator for anesthesiologists to monitor and regulate the anesthesia depth of patients during surgery. Herein, a negative photoionization ion mobility spectrometry with acetone as the dopant was developed for rapid and direct determination of intraoperative blood propofol concentration in the operating theatre. High concentration of acetone molecules in the carrier gas was used not only to enhance neutral desorption and release free propofol molecules from the whole blood, but also to increase the intensity of reactant O2− and reduce the amount of non-reactive CO3− ions simultaneously, which allowed to measure trace propofol in less than 2 min without any tedious pretreatment. Under optimized conditions, a linear calibration curve of propofol was obtained with the range of 0.5–20 ng μL−1 and with a limit of detection of 0.14 ng μL−1, which met the clinical requirements and correlated well with standard HPLC methods. Finally, the method was applied to detect intraoperative blood propofol concentration in nearly 100 surgical patients, demonstrating its excellent detection capability and facilitating the study of propofol pharmacokinetics.

The number and kind of antiepileptics affect propofol dose requirement for anesthesia: observational study.

The propofol dose requirement and the emergence time are affected by antiepileptic use. The effects on anesthesia of the number and kind of antiepileptic agents have not been reported. We investigated the relationship between the kind and number of antiepileptic agents and the propofol dose requirement for anesthesia and emergence time in intravenous general anesthesia for dental treatment for patients with neurological disorders. We studied 247 patients with neurological disorders who underwent dental treatment under intravenous general anesthesia. Patients were categorized according to the number of antiepileptics (none, single agent, two kinds, and three or more kinds of antiepileptics) and the kind of antiepileptic (carbamazepine, valproate, phenobarbital, phenytoin, zonisamide, clobazam, or topiramate) being received. The propofol dose requirement for anesthesia, emergence time, and predicted blood propofol concentration at emergence were evaluated. Patients on three or more kinds of antiepileptics had significantly lower propofol dose requirement (reduction in 25%, compare with no use) and predicted blood propofol concentration at emergence (reduction in 41%) and significantly longer emergence time (extension in 50%) (P < 0.05). Valproate and clobazam reduced the propofol dose (valproate 9% and clobazam 19%) and predicted blood propofol concentration at emergence (valproate 18% and clobazam 33%), while phenobarbital increased these parameters (30% and 125%) (P < 0.05). The number and kind of antiepileptics effects propofol dose requirement. In particular, valproate and clobazam reduce the propofol dose requirement, while phenobarbital increases this.Clinical trial registration UMIN No. UMIN000014179.

Lethal self-administration of propofol and atracurium: Two case reports and literature review

Propofol is an intravenous anesthetic agent widely used in the induction and maintenance of general anesthesia. Acute intoxications with propofol are rare and remain primarily related to the acquisition of the product in hospital. If propofol can induce fatal respiratory depression alone, in a number of cases the clinical situation is exacerbated by the presence of other drugs like neuromuscular-blocking agents. Laudanosine, the circulating form of atracurium or cisatracurium, two non-depolarizing neuromuscular-blocking agents, is more frequently observed in toxicology. Such agents are widely used for tracheal intubations. Laudanosine has no pharmacological activity, which is exclusively due to the parent drugs. These agents can be fatal at any concentration, due to respiratory failure. Here, two cases of anesthesiologists’ suicide following self-administration of propofol-atracurium combination are reported. Case 1: a 48-years-old anesthesiologist was found without vital signs at his office. The drugs and paraphernalia used for delivery were discovered at the scene. Case 2: a 61-years-old anesthesiologist was found dead at home with a cannula connected to an infusion set at the bend of the elbow. Next to the body several empty ampoules of Diprivan ® and Atracurium besylate ® were found. For both cases, several biological specimens were collected for toxicological investigation. Comprehensive screenings of drugs and toxic compounds were performed using LC-DAD and GC-MS. Ethanol concentrations were determined using GC-FID. Laudanosine was quantified using LC-DAD. Propofol was quantified using GC-MS and LC-MS/MS. Propofol blood concentrations were 1 and 1.91 mg/L for case 1 and case 2, respectively (therapeutic range: 2–8 mg/L). Laudanosine blood concentrations were 0.13 and 1.18 mg/L for case 1 and case 2, respectively. Paroxetine, N-demethyldiazepam and ethanol were detected in the first case. Hydroxyzine was detected in the second case. In both cases, levels of these substances could not explain the death. Propofol related fatalities are rare, even more when combined with neuromuscular- blocking agents [1] . Propofol and atracurium concentrations documented here, are in agreement with those reported in the literature, these being characterized by a high inter-individual variability [2] . However, the concentrations observed in suicide cases compared to those observed in accidental fatalities (chronic abusers) appear to be much higher. In fact, three manners of death have been described with propofol: suicide, accidental overdose in chronic abusers, and more exceptionally, murder [3] . In the cases described here, circumstances and the use of atracurium suggest suicide. It should be noted that the concentrations of laudanosine and propofol observed here are in the usual anesthetic range. Albeit, it should be pointed out that for anesthetic agents, therapeutic concentrations are established for patients being supported respiratory-wise, while in non-supported or non-intubated patients such concentrations may be fatal. Therefore, the interpretation of the blood concentration in the forensic toxicological analysis must take into account the context and the circumstances of the death.

Maternal and neonatal wellbeing during elective C-section induced with a combination of propofol and dexmedetomidine: How effective is the placental barrier in dogs?

Anaesthetics administered during C-section (CS) can cross the placenta and the foetal blood-brain barrier contributing to distress up to neonatal mortality. Therefore, to prevent neonatal risks, sedatives and analgesics are not commonly administered to the bitch until all pups are delivered. This study aims to evaluate the effect of a new anaesthetic and analgesic protocol for elective CS in dogs, focused on both maternal and neonatal wellbeing. General anaesthesia was induced by a combination of propofol (PPF) and dexmedetomidine (DEX) and maintained with isoflurane. DEX was added to PPF in order to provide analgesia and to reduce PPF dose. Propofol and DEX concentrations in maternal blood, amniotic fluid, and placenta were correlated to maternal and neonatal parameters. Maternal pain score was assessed with Glasgow Composite Measure Pain Scale short-form. Nine healthy purebred dogs scheduled for elective CS delivered 54 pups. The 77.8% of pups were vigorous at birth and assigned to the highest Apgar score (AS). The lowest AS was recorded in pups from mothers receiving additional doses of PPF (p < 0.001). Apgar scores improved with the increase in time between induction and pups' extraction, starting from 30 min after induction (p < 0.01). This study could contribute to clarify the controversy about the optimal extraction's time of pups after induction i.e. the best time between PPF administration and birth. No bitch showed post-operative pain or required additional analgesic doses based on their pain score. Maternal blood PPF and DEX, as well as placental PPF concentrations, decreased over time (p < 0.01). Conversely, placental DEX was fair uniformly detected in littermate pups. Both PPF and DEX were not detectable in amniotic fluid. Placenta resulted an effective barrier against foetal DEX exposure, making this protocol safe, analgesic and advisable for elective CS in dogs.

The influence of small amount of substances present in tissue on immunosuppressive drug optical spectrum

In this paper, we describe how commonly present in tissue substances - sodium chloride and glucose - affect the optical spectrum of an immunosuppressive drug (Cyclaid® by Apotex). Prepared samples were investigated using the spectrophotometer in the spectrum range from 250 nm to 1100 nm. The maximum wavelength shift calculated on the basis of measurement results is not bigger than the measurement wavelength step. So, it can be concluded, that the small amount of sodium chloride or glucose does not influence the measurement and it is possible to apply spectrophotometry in a point-of-care sensor of the Cyclaid® by Apotex level. Full Text: PDF ReferencesL. Taylor, C. J. E. Watson, and J. A. Bradley, "Immunosuppressive agents in solid organ transplantation: Mechanisms of action and therapeutic efficacy", Crit. Rev. Oncol. Hematol. 56, 23 (2005). CrossRef C. C. Mok, "Calcineurin inhibitors in systemic lupus erythematosus", Best Pract. Res. Clin. Rheumatol. 31, 429 (2017). CrossRef C. E. M. Griffiths et al., "Striae gravidarum in primiparae", Br. J. Dermatol. 155, 1 (2006). CrossRef F. Stucker and D. Ackermann, "Immunsuppressiva - Wirkungen, Nebenwirkungen und Interaktionen", Ther. Umschau. Rev. thérapeutique, 68 ,679 (2011). CrossRef A. Fahr, "Cyclosporin Clinical Pharmacokinetics", Clin. Pharmacokinet. 24, 472 (1993). CrossRef Cyclosporine – UpToDate, DirectLink P. Strakowska, R. Beutner, M. Gnyba et al., "Electrochemically assisted deposition of hydroxyapatite on Ti6A14V substrates covered by CVD diamond films – coating characterization and first cell biological results", Mater Sci Eng C Mater Biol Appl. 59, 624 (2016). CrossRef M. Gnyba, M. S. Wróbel, K. Karpienko et al., "Combined analysis of whole human blood parameters by Raman spectroscopy and spectral-domain low-coherence interferometry", Proc. SPIE 9537, 95371N (2015). CrossRef M. S. Wróbel, M. Gnyba, R. Urniaz et al., "Detection of propofol concentrations in blood by Raman spectroscopy", Proc. SPIE 9537, 95370Z (2015). CrossRef M. Gnyba, et al., "SAVE TO MY LIBRARY Raman spectroscopic investigation of blood and related materials", Proc. SPIE 9448, 944809 (2015). CrossRef H. S. Cho et al., "High frame-rate intravascular optical frequency-domain imaging in vivo", Biomed. Opt. Express 5, 223 (2013). CrossRef T. A. Valdez et al., "Multi-color reflectance imaging of middle ear pathology in vivo", Anal. Bioanal. Chem. 407, 3277 (2015). CrossRef M. Ali Ansari, S. Alikhani, and E. Mohajerani, "A hybrid imaging method based on diffuse optical tomography and optomechanical method to detect a tumor in the biological phantom", Opt. Commun. 342, 12 (2015). CrossRef M. S. Wróbel et al., "Multi-layered tissue head phantoms for noninvasive optical diagnostics", J. Innov. Opt. Health Sci. 08, 1541005 (2015). CrossRef D. A. Skoog, F. J. Holler, and S. R. Crouch, Principles of instrumental analysis, (Belmont, CA, Thomson Brooks/Cole 2007). CrossRef M. Hof, Basics of Optical Spectroscopy in Handbook of Spectroscopy, (Weinheim , Wiley-VCH Verlag GmbH &amp; Co. KGaA 2005). CrossRef M. Marzejon et al,. "Optical-Spectrometry-Based Method for Immunosuppressant Medicine Level Detection in Aqueous Solutions", Sensors, 18, 2001 (2018). CrossRef UV-9000 Double Beam UV/VIS, http://en.metash.com/ProductShow_172.html CrossRef

Effectiveness of preanesthetic administration of gabapentin on sedative action during intravenous sedation with propofol

There are no sufficient evidences for the sedative effect of gabapentin during anesthesia, especially intravenous sedation (IVS). The purpose of this study was to evaluate the sedative effect of gabapentin as preanesthetic medication during the IVS with propofol. 10 volunteer subjects joined this study. They underwent propofol IVS three times on separate days. On the first day, the IVS without gabapentin was performed as a control. On the second and the third day, gabapentin 200mg and 400mg were administered before the IVS, respectively. The target blood concentration (CT) of propofol was gradually increased, and the bispectral index (BIS) value and Ramsay sedation score (RSS) were evaluated at each propofol CT. Postanesthetic complications and influences on vital signs were also evaluated. Compared to the control group, the propofol CTs in the gabapentin 400mg group significantly reduced at the BIS values of 60 and 70 (p = 0.031 and p = 0.043, respectively), and at RSS 3, 4, 5 and 6 (p = 0.040, p = 0.004, p = 0.001 and p = 0.004, respectively). There was no significant difference in propofol CTs between the control group and the gabapentin 200mg group. There were no abnormality and no deterioration in circulation and respiration in all groups. There were no significant increases in complications with the administration of gabapentin. The oral administration of 400mg dose of gabapentin reduced the propofol CTs for achieving an adequate sedation level on IVS.

Precision and Bias of Target-Controlled Prolonged Propofol Infusion for General Anesthesia and Sedation in Neurosurgical Patients.

The aim of this study was to determine the relationship, precision, and bias of a propofol target-controlled infusion (TCI) system during prolonged infusion in neurosurgical patients. We retrospectively included patients undergoing general anesthesia for elective neurosurgical removal of brain tumors and postoperative sedation in the intensive care unit over a period of 3 months. TCI of propofol (Diprifusor - Marsh model) and remifentanil were used for general anesthesia and sedation. We compared propofol blood concentration (Cmeas ) measured by liquid chromatography-mass spectroscopy with predicted concentrations (Cpred ) by the TCI system at 40minutes (T0), 2hours (T1), and 4hours (T2) and every 8 hours after starting the drug infusion and at the time of emergence from sedation. Ninety-four paired determinations of Cmeas and Cpred from 15 adult ASA I patients (8 men and 7 women 54.9±13 years old; BMI, 24±3.2 kg/m2 ) were analyzed. Mean duration of drug administration was 31±6hours. The coefficient of determination (R2 ) of the linear regression model for the relationship of Cmeas and Cpred was 0.43. At the time of emergence, Cmeas was 0.5±0.18μg/mL. The bias of the TCI system (median performance error) was -34.7%, and the precision (median absolute performance error) was 36%. Wobble and divergence were 0.3% and 12.3%, respectively. This study found bias of the system out of the range of tolerability and showed a high tendency toward overestimation. These findings may lead to undersedation when propofol TCI is used for prolonged infusion.

Anesthesia Medication Handling Needs a New Vision.

Anesthesia Medication Handling Needs a New Vision.

Exhaled breath condensate as an alternative sample for drug monitoring.

Exhaled breath condensate as an alternative sample for drug monitoring.