Propofol infusion rate does not affect local pain on injection

BACKGROUND: Local pain at the site of an i.v. injection of propofol is a well-known problem, particularly in infants. This randomised investigator-blinded crossover study was designed to assess the effect of the i.v. bolus infusion rate on propofol-induced pain at the site of injection. METHODS: Thirty unpremedicated patients scheduled for ear-nose-throat or plastic surgery at Malmö University Hospital, Sweden, were given two consecutive 2.0 ml injections of propofol 10 mg/ml (Diprivan, AstraZeneca, Sweden/UK), at different infusion rates (0.2 or 1.0 ml/s), immediately before induction of general anesthesia. Half of the patients (n=15) received the first bolus of propofol over 2 s and the second bolus over 10 s, and the other half (n=15) had their injections in reversed order. After each injection, the patient was asked by an investigator to indicate pain intensity on a visual analog scale (VAS) and to report the times of the appearance, maximum point and disappearance of pain. The injections were given approximately 2 min apart. The investigators scoring pain intensity, as indicated by the patients on a 10-point numerical rate scale, were blinded to the order in which the injections were given, as were the patients themselves. RESULTS: There were no statistically significant differences in the incidence (both 86%) of intensity (median; 25th; 75th percentiles, in VAS units: 3.1; 1.0; 5.3 and 3.3; 1.4; 5.0, respectively) or duration (66+/-31 and 73+/-26 s, respectively) of pain between the faster (1.0 ml/s) and slower (0.2 ml/s) bolus infusion rates of propofol studied. CONCLUSIONS: We conclude that the i.v. bolus infusion rate of propofol does not influence drug-induced local pain on injection, at least not within the infusion rate interval studied. Therefore, adjusting i.v. injection speed does not seem to be a clinically useful tool for reducing the intensity or duration of propofol-induced pain at the site of administration

Individual participant data (IPD)-level meta-analysis of randomised controlled trials to estimate the vitamin D dietary requirements in dark-skinned individuals resident at high latitude

Context and purpose There is an urgent need to develop vitamin D dietary recommendations for dark-skinned populations resident at high latitude. Using data from randomised controlled trials (RCTs) with vitamin D3-supplements/fortified foods, we undertook an individual participant data-level meta-regression (IPD) analysis of the response of wintertime serum 25-hydroxyvitamin (25(OH)D) to total vitamin D intake among dark-skinned children and adults residing at ≥ 40° N and derived dietary requirement values for vitamin D. Methods IPD analysis using data from 677 dark-skinned participants (of Black or South Asian descent; ages 5–86 years) in 10 RCTs with vitamin D supplements/fortified foods identified via a systematic review and predefined eligibility criteria. Outcome measures were vitamin D intake estimates across a range of 25(OH)D thresholds. Results To maintain serum 25(OH)D concentrations ≥ 25 and 30 nmol/L in 97.5% of individuals, 23.9 and 27.3 µg/day of vitamin D, respectively, were required among South Asian and 24.1 and 33.2 µg/day, respectively, among Black participants. Overall, our age-stratified intake estimates did not exceed age-specific Tolerable Upper Intake Levels for vitamin D. The vitamin D intake required by dark-skinned individuals to maintain 97.5% of winter 25(OH)D concentrations ≥ 50 nmol/L was 66.8 µg/day. This intake predicted that the upper 2.5% of individuals could potentially achieve serum 25(OH)D concentrations ≥ 158 nmol/L, which has been linked to potential adverse effects in older adults in supplementation studies. Conclusions Our IPD-derived vitamin D intakes required to maintain 97.5% of winter 25(OH)D concentrations ≥ 25, 30 and 50 nmol/L are substantially higher than the equivalent estimates for White individuals. These requirement estimates are also higher than those currently recommended internationally by several agencies, which are based predominantly on data from Whites and derived from standard meta-regression based on aggregate data. Much more work is needed in dark-skinned populations both in the dose–response relationship and risk characterisation for health outcomes.Peer reviewe

Propofol infusion rate does not affect local pain on injection

Background: Local pain at the site of an i.v. injection of propofol is a well-known problem, particularly in infants. This randomised investigator-blinded crossover study was designed to assess the effect of the i.v. bolus infusion rate on propofol-induced pain at the site of injection. Methods: Thirty unpremedicated patients scheduled for earnose-throat or plastic surgery at Malmö University Hospital, Sweden, were given two consecutive 2.0 ml injections of propofol 10 mg/ml (Diprivan A , AstraZeneca, Sweden/UK), at different infusion rates (0.2 or 1.0 ml/s), immediately before induction of general anesthesia. Half of the patients (nΩ15) received the first bolus of propofol over 2 s and the second bolus over 10 s, and the other half (nΩ15) had their injections in reversed order. After each injection, the patient was asked by an investigator to indicate pain intensity on a visual analog scale (VAS) and to report the times of the appearance, maximum point and disappearance of pain. The injections were given approximately 2 min apart. The investigators scoring pain intensity, as indicated by the patients on a 10-point numerical rate scale, were blinded to the order in which the injections were given, as were the patients themselves

Randomisierte Cross-Over-Bewertung vom Geschlecht des Untersuchers auf die Schmerzschwelle bei gesunden Freiwilligen

Background and aims: This randomized cross-over study in healthy volunteers was designed primarily to evaluate the potential impact of investigator gender on electrical pain threshold (EPT) and corresponding pain intensity levels, and secondly to evaluate potential differences in those interventions between female and male study participants.Methods: Forty adult volunteers (22 females) were included. An electrical stimulation device was used to determine EPT levels (in pain magnitude scores) in series of three in each study participant - once by a female, and once by a male investigator - according to a predefined cross-over design schedule. Corresponding levels of pain intensity were scored on a visual analog scale (VAS) slide ruler.Results: Study data was obtained and analysed in all participants. Significantly higher EPT levels were determined by the female investigator compared with the male investigator (median 22 (IQR 12-31) vs. 8 (6-10) pain magnitude scores; p 0.300). There were no differences in EPT levels between female and male subjects evaluated by female (p >0.300) and male (p =0.125) investigators, or between the first and second series of stimulation (p >0.300).Conclusions: Our finding of significantly higher EPT levels when study participants of both genders - despite no difference in reported pain intensity - were evaluated by a female than by a male investigator, indicates a potential impact of investigator gender on the individual perception of pain.Implications: By contributing to a better understanding of how individual pain threshold levels are potentially influenced by investigator gender, this study might facilitate future evaluation of pain conditions in both preclinical and clinical settings.Hintergrund und Ziele: Diese präklinische randomisierte Cross-Over-Studie wurde entwickelt, um 1) einen möglichen Einfluss des Geschlechts der Untersucher auf die Schwellenwerte für elektrische Schmerzen (EPT) und entsprechende Schmerzintensität bei gesunden Freiwilligen zu bewerten, und 2) mögliche Unterschiede bei diesen Interventionen zwischen weiblichen und männlichen Studienteilnehmern zu bewerten.Methoden: Vierzig gesunde erwachsene Freiwillige (22 Frauen) wurden eingeschlossen. Mit einem elektrischen Stimulationsgerät wurden die EPT-Spiegel in Dreierreihen bei jedem Studienteilnehmer - einmal von einem weiblichen und einmal von einem männlichen Untersucher - gemäß einem vordefinierten Cross-Over-Entwurfsplan bestimmt. Entsprechende Niveaus der Schmerzintensität wurden auf einem VAS-Lineal bewertet.Ergebnisse: Studiendaten wurden bei allen Teilnehmern erhoben und analysiert. Im Vergleich zum männlichen Untersucher wurden von der weiblichen Untersucherin signifikant höhere EPT-Spiegel bestimmt (Median 22 (IQR 12-31) vs. 8 (6-10) Schmerzstärkeneinheiten; p 0,300). Es gab keine Unterschiede in EPT zwischen weiblichen und männlichen Teilnehmern, die von weiblichen (p >0,300) und männlichen (p =0,125) Untersuchern bewertet wurden, oder zwischen der ersten und zweiten Stimulationsreihe (p >0,300).Schlussfolgerungen: Dass signifikant höhere EPT-Werte bei Studienteilnehmern beiden Geschlechts vorlagen, wenn sie von einer weiblichen statt einer männlichen Person untersucht wurden - trotz gleicher gemeldeter Schmerzintensität -, zeigt einen möglichen Einfluss des Geschlechts des Untersuchers auf die individuelle Wahrnehmung von Schmerz.Implikationen: Durch diesen Beitrag zu einem besseren Verständnis, wie die individuellen EPT-Werte möglicherweise vom Geschlecht des Untersuchers beeinflusst werden, könnte diese Studie die zukünftige Bewertung von Schmerzzuständen sowohl im präklinischen als auch im klinischen Umfeld erleichtern

Racemic ketamine does not abolish cerebrovascular autoregulation in the pig.

Background: Little is known about the influence of racemic ketamine on autoregulation of cerebral blood flow (CBF), and available reports regarding its influence on cerebral hemodynamics are contradictory. This study was designed to evaluate cerebrovascular responses to changes in the mean arterial pressure (MAP) during ketamine anesthesia. Methods: In eight normoventilated pigs anesthesia was induced with propofol and maintained by i.v. infusion of ketamine (15.0 mg kg-1.h-1) during measurements. The intra-arterial xenon clearance technique was used to calculate CBF. Balloon-tipped catheters were introduced in the inferior caval vein and mid-aorta, and increases or decreases by up to 40% in mean arterial pressure (MAP) in random order were achieved by titrated inflation of these balloon catheters. Cerebral blood flow was determined at each MAP level. Regression coefficients of linear pressure-flow curves were calculated in all animals. Results: From the mean baseline level (101 mmHg) MAP was reduced by 20% and 40%, and increased by 26% and 43%. The maximal mean increase and decrease in MAP induced a 12% increase and a 15% decrease, respectively, of CBF from the mean baseline level (52.6 ml.100 g-1.min1). The 95% confidence interval (-0.02; 0.38) of the mean regression coefficient of individual pressure-flow curves does not include the regression coefficient (0.64) of a linear correlation between MAP and CBF including origo (correlation coefficient 0.99), which indicates complete lack of cerebrovascular autoregulation. Conclusions: We conclude that autoregulation of CBF is not abolished during continuous ketamine infusion in normoventilated pigs and that previous divergent conclusions are unlikely to be associated with severe impairment of cerebrovascular autoregulation

Management of Inadvertent Arterial Catheterisation Associated with Central Venous Access Procedures

OBJECTIVE: This study aims to describe the clinical management of inadvertent arterial catheterisation after attempted central venous catheterisation. METHODS: Patients referred for surgical or endovascular management for inadvertent arterial catheterisation during a 5-year period were identified from an endovascular database, providing prospective information on techniques and outcome. The corresponding patient records and radiographic reports were analysed retrospectively. RESULTS: Eleven inadvertent arterial (four common carotid, six subclavian and one femoral) catheterisations had been carried out in 10 patients. Risk factors were obesity (n=2), short neck (n=1) and emergency procedure (n=4). All central venous access procedures but one had been made using external landmark techniques. The techniques used were stent-graft placement (n=6), percutaneous suture device (n=2), external compression after angiography (n=1), balloon occlusion and open repair (n=1) and open repair after failure of percutaneous suture device (n=1). There were no procedure-related complications within a median follow-up period of 16 months. CONCLUSIONS: Inadvertent arterial catheterisation during central venous cannulation is associated with obesity, emergency puncture and lack of ultrasonic guidance and should be suspected on retrograde/pulsatile catheter flow or local haematoma. If arterial catheterisation is recognised, the catheter should be left in place and the patient be referred for percutaneous/endovascular or surgical management