Barriers and motivations for participation in preventive vaccine clinical trials: Experience of 5 clinical research sites

Recruitment in preventive vaccine trials (PVT) is challenging due to common barriers to clinical research and lack of vaccine confidence. Identifying determinants of participation can help to improve recruitment. A prospective survey was conducted in 5 French clinical investigational sites. People asked to participate in a PVT were given a questionnaire whether they decided to participate or not in the trial. A total of 341 people answered the survey: 210 accepting and 131 declining to participate in a PVT. Acceptors were significantly younger (38.5 vs 54.9 years old), more likely to be involved in early phase trials, had a higher level of education (p < 0.005) and a significantly better general opinion concerning vaccines (92.3% versus 72.3%, p < 0.005) compared with those who declined. Factors associated with acceptance or refusal were evaluated in 224 people in the 4 sites where both groups were included. In a multivariate analysis, three factors: older age, having heard about PVT through multiple sources and financial incentives were significantly associated with refusal to participate in the PVT. A generally favourable opinion of vaccines was associated with acceptance. The main motivation for participation was altruism (93.2%) whereas fear of side effects was at the forefront of the barriers (36.6%). Information given by the physician was a key point for decision-making in 70.2% of those who accepted. In brief, vaccine hesitancy may decrease recruitment in PVTs; reinforcing altruism and quality of information given are key points in acceptance of participation in PVT.

Dextromethorphan Analgesia in a Human Experimental Model of Hyperalgesia

Editor’s Perspective

What We Already Know about This Topic

What This Article Tells Us That Is New

Background

Central pain sensitization is often refractory to drug treatment. Dextromethorphan, an N-methyl-d-aspartate receptor antagonist, is antihyperalgesic in preclinical pain models. The hypothesis is that dextromethorphan is also antihyperalgesic in humans.

Methods

This randomized, double-blind, placebo-controlled, crossover study explores the antihyperalgesic effect of single and repeated 30-mg dose of oral dextromethorphan in 20 volunteers, using the freeze-injury pain model. This model leads to development of primary and secondary hyperalgesia, which develops away from the site of injury and is associated with central sensitization and activation of N-methyl-d-aspartate receptor in the spinal cord. The primary outcome was antihyperalgesia calculated with the area under the curve of the percentage change in mechanical pain threshold (electronic von Frey) on the area of secondary hyperalgesia. The secondary outcomes were mechanical pain threshold on the area of primary hyperalgesia and cognitive (reaction time) effect.

Results

Single 30-mg results are reported. Antihyperalgesia (% · min) is significantly higher on the area of secondary hyperalgesia with dextromethorphan than placebo (median [interquartile range]: 3,029 [746; 6,195] vs. 710 [–3,248; 4,439], P = 0.009, Hedge’s g = 0.8, 95% CI [0.1; 1.4]). On primary hyperalgesia area, mechanical pain threshold 2 h after drug intake is significantly higher with dextromethorphan (P = 0.011, Hedge’s g = 0.63, 95% CI [0.01; 1.25]). No difference in antinociception is observed after thermal painful stimuli on healthy skin between groups. Reaction time (ms) is shorter with placebo than with dextromethorphan (median [interquartile range]: 21.6 [–37.4; 0.1] vs. –1.2 [–24.3; 15.4], P = 0.015, Hedge’s g = 0.75, 95% CI [0.12; 1.39]). Nonserious adverse events occurrence (15%, 3 of 20 volunteers) was similar in both groups.

Conclusions

This study shows that low-dose (30-mg) dextromethorphan is antihyperalgesic in humans on the areas of primary and secondary hyperalgesia and reverses peripheral and central neuronal sensitization. Because dextromethorphan had no intrinsic antinociceptive effect in acute pain on healthy skin, N-methyl-d-aspartate receptor may need to be sensitized by pain for dextromethorphan to be effective.

[Comparison of two opioids with different kinetics for intravenous analgesia in outpatient multiple third molar avulsions]

INTRODUCTION

We had for aim to compare the effects of intra-operative opioid analgesia according to the drug kinetics.

PATIENTS AND METHODS

We conducted a prospective, controlled, randomized, double-blinded trial including 60 patients scheduled for ambulatory multiple third molar avulsion. The general anesthesia, performed with propofol and analgesia was a target-controlled infusion of either remifentanil or sufentanil. The anesthesia was set to reach an optimal bispectral index and adjusted to a clinical target throughout the procedure. The main endpoints were: postoperative request for morphine and other opioids; postoperative pain; postoperative adverse effects of opioids.

RESULTS

In the post-operative care unit (French acronym PACU), patients who received remifentanil were extubated earlier (17 vs. 26 min.), but had more pain and required twice more morphine for analgesia (6 vs. 3 mg), than those who had received sufentanil. However, the need for post-surgery oral opioid intake was greater in the sufentanil group, so the overall postoperative opioid consumption and patient satisfaction were identical in both groups. The time spent in the PACU was also identical for both groups.

DISCUSSION

Using an ultra-short kinetic opioid such as remifentanil does not seem useful, since the shorter delay before extubation is compensated by a greater need for morphine in the PACU.

[Post-partum haemorrhage in delivery room: anaesthetists' practioner in Auvergne]

OBJECTIVE

To assess the management of post-partum haemorrhage (PPH) in delivery rooms by the anaesthetists of the Auvergne region.

STUDY DESIGN

Cross sectional study.

METHODS

An anonymous postal survey was sent to all the anaesthetists working in a public or private hospital with a maternity unit.

RESULTS

The response rate was about 70 %. Eight percent of the respondents never practiced in obstetrics; others all declared to have managed PPH at least once. Only 66 % declared to know the right definition of PPH, 98 % declared to have guidelines in the delivery room, 87 % to use graduate blood receipt pockets, 85 % to work under midwives-directed delivery at expulsion, 88 % to have a HemoCue™ system. More than 80 % declared to use first oxytocin and to switch for prostaglandins in case of failure, to put two venous catheters and a urinary catheter, to administer broad-spectrum prophylactic antibiotic and to draw a blood sample for early biology. Packed red cells, platelets and fresh frozen plasma were accessible in less than 30 minutes for 98 %. Transfusion guidelines were applied. Only 27 % could have arterial radiologic embolisation on site. The knowledge about PPH and its consensual care tended to be poorer in practitioners from the university hospital, and younger under 40 also.

CONCLUSION

This survey, with a good response rate, showed a practice generally fitting to the guidelines, although with some failures depending on the practioner's age and type of hospital.

Harmonisation of ethics committees' practice in 10 European countries

BACKGROUND

The Directive 2001/20/EC was an important first step towards consistency in the requirements and processes for clinical trials across Europe. However, by applying the same rules to all types of drug trials and transposing the Directive's principles into pre-existing national legislations, the Directive somewhat failed to meet its facilitation and harmonization targets. In the field of ethics, the Directive 2001/20/EC conditioned the way of understanding and transposing the "single opinion" process in each country. This led to a situation in which two models of research ethics committees organisation systems exist, being the model in which the "single opinion" is considered to be the decision made by a single ethics committee more effective and simpler in terms of administrative and logistic workload.

METHOD

A survey was conducted in 10 European countries. Members of the European Clinical Research Infrastructures Network working party number 1, with expertise in the field of ethics, responded.

RESULTS

There is a major heterogeneity in the composition of ethics committees among the surveyed countries based on the number of members, proportion of experts versus lay members and expertise of the scientific members. A harmonized education of the ethics committees' membership based in common curricula is recommended by the majority of countries.

CONCLUSIONS

Despite the efforts for harmonization of the European Clinical Trial Directive, from an ethical point of view, there remains a plurality of ethics committees' systems in Europe. It is important to comprehend the individual national systems to understand the problems they are facing.

An in-use microbiological comparison of two surgical hand disinfection techniques in cardiothoracic surgery: hand rubbing versus hand scrubbing

Surgical site infection after heart surgery increases morbidity and mortality. The method of presurgical hand disinfection could influence the infection risk. From February to April 2003, we compared the microbiological efficacy of hand-rubbing (R) and hand-scrubbing (S) procedures. The surgical team alternately used hand-scrubbing or hand-rubbing techniques every two weeks. Fingertip impressions were taken before and immediately after hand disinfection, every 2h and at the end of the operation. Acceptability of hand rubbing was assessed by a questionnaire. Mean durations of surgical procedures were 259+/-68 and 244+/-69min for groups S and R respectively (P=0.43). Bacterial counts immediately after hand disinfection were comparable with the two techniques, but significantly lower in group R at the end of surgery. No differences were observed between the percentages of negative samples taken after 2h, 4h and at the end of surgery between the two groups. Bacterial skin flora reduction immediately after hand disinfection, after 2h and 4h of operating time and at the end of surgery was better in group R, but the difference was not statistically significant. Before surgery, the hand-rubbing method with alcohol solution preceded by hand washing with mild neutral soap is as effective as hand scrubbing to reduce bacterial counts on hands. It decreased the bacterial counts both immediately after hand disinfection and at the end of long cardiothoracic surgical procedures. The acceptability of hand rubbing was excellent and it can be considered to be a valid alternative to the conventional hand-scrubbing protocol.

Comparison of tolerance of facemask vs. mouthpiece for non-invasive ventilation

This prospective, single centre, randomised, cross-over study compares patient tolerance of the facemask and mouthpiece for delivery of non-invasive ventilation in an intensive care unit. Twenty-seven patients with acute respiratory failure were scheduled for two 45-min sessions of non-invasive ventilation with facemask and mouthpiece. The order of the sessions was chosen at random. Nurses and patients assessed the tolerance of both techniques using a visual analogue scale. The time spent by nurses and the changes in respiratory parameters were recorded. The facemask was better tolerated than the mouthpiece; all the cases of non-invasive ventilation withdrawal (n = 5) occurred with mouthpieces (p = 0.026). Less nursing time was required using the facemask for the 22 patients who underwent both procedures (p = 0.01). However, the difference in tolerance scores was not significant. Non-invasive ventilation with both facemask and mouthpiece improved the P(a)o(2)/F(i)o(2) ratio, increased the pH and decreased the P(a)co(2). Only non-invasive ventilation with the facemask lowered the respiratory rate. The facemask appears to be a better initial choice for non-invasive ventilation when compared to mouthpiece, but both can be effective.

Perispinal analgesia for labour followed by patient-controlled infusion with bupivacaine and sufentanil: combined spinal-epidural vs. epidural analgesia alone

BACKGROUND AND OBJECTIVE

Combined spinal-epidural is an alternative technique to epidural analgesia for labour, but its benefits are not clearly identified.

METHODS

A prospective, blinded, randomized study was undertaken involving 113 women attending a university hospital obstetric department. Analgesia was initiated with intrathecal bupivacaine 0.25% 1 mL + sufentanil 5 microg in the combined spinal-epidural group (n = 54), and with bupivacaine 0.125% + epinephrine 2.5 microg mL(-1) + sufentanil 7.5 microg in the epidural group (n = 59). In both cases this was followed by patient-controlled epidural analgesia with bupivacaine 0.125% (+ sufentanil 0.25 microg mL(-1)). Duration of labour, quality of analgesia and side-effects were compared between groups.

RESULTS

In the combined spinal-epidural group, the onset of analgesia was faster (5 vs. 15 min, P < 0.001), the consumption of bupivacaine was lower (7.5 vs. 11.3 mg h(-1), P = 0.003) and there was less unilateral analgesia (14.8% vs. 40.7%, P = 0.002) than in the epidural group. The characteristics of labour were similar in both groups. However, in the combined spinal-epidural group, there was a higher incidence of posterior presentation (25.9% vs. 10%, P = 0.03), pruritus (P < 0.001), hypotension (P = 0.002), somnolence (P = 0.01), nausea (P = 0.02) and one case of meningitis.

CONCLUSIONS

The combined spinal-epidural technique provided more effective analgesia during labour than epidural analgesia alone but offered no other advantage. It induced more adverse effects and this should be considered before routinely using the combined spinal-epidural technique.

Epidural versus intrathecal morphine for postoperative analgesia after Caesarean section

BACKGROUND

Perispinal anaesthesia for Caesarean section allows injection of epidural (ED) or intrathecal (i.t.) morphine to provide long-lasting postoperative analgesia. To compare these two routes, a prospective, randomized, double-blinded study of 53 patients undergoing elective Caesarean section was performed.

METHODS

Combined spinal-epidural anaesthesia with 6 mg of i.t. hyperbaric bupivacaine plus sufentanil 5 microg, and additional ED lidocaine was used. Additionally, each patient received either 2 mg (2 ml) of ED morphine plus 1 ml of i.t. normal saline (ED group, n=28), or 0.075 mg (1 ml) of i.t. morphine plus 2 ml of ED normal saline (i.t. group, n=25). Additional postoperative analgesia was given in the form of propacetamol and ketoprofen, plus self-administered i.v. morphine.

RESULTS

No major respiratory depression occurred. Time to first demand of morphine was similar in the ED (307.5 min) and i.t. (310 min) groups, as was the incidence of side-effects such as sedation, pruritus, nausea, and vomiting. During the first 24 postoperative hours, VAS pain scores were greater in the i.t. group (P=0.032), as was additional morphine consumption (4 vs 1.5 mg) (P=0.03).

CONCLUSIONS

The ED protocol was more effective than the i.t. protocol, whilst side-effects were similar.

Systemic morphine reduces the wind-up of trigeminal nociceptive neurons

We assessed the effects of intravenous morphine on the wind-up of nociceptive neurons of the spinal trigeminal nucleus oralis (Sp5O). Extracellular recordings of Sp5O nociceptive convergent neurons were performed in intact halothane-anesthetized rats. Wind-up of C-fiber-evoked responses was elicited by repetitive electrical stimulation (train of 16 shocks, 0.66 Hz) of their receptive field at C-fiber intensity (3 times the threshold). Wind-up was tested for its sensitivity to morphine (6 mg/kg,i.v.), and the specificity of the effects was verified with naloxone (0.4 mg/kg, i.v.). Nineteen convergent neurons displaying wind-up were recorded. Morphine reduced the wind-up of all but one. In five cases, notwithstanding a reduced wind-up, the neuronal response evoked by the first stimulus in the train (initial input) was unexpectedly increased. Naloxone always antagonized morphine inhibitory effects on the wind-up. When administered systemically, morphine reduced the wind-up of trigeminal nociceptive neurons. This inhibitory effect occurred independently of morphine's ability to affect the initial C-fiber-evoked input. Our findings support the idea that systemic morphine probably blocks wind-up by acting at opioid receptors located postsynaptically to nociceptive primary afferents.

[Physiopathologic consequences of laparoscopic surgery]

The aim of this present review was to study the effects of the intraperitoneal carbon dioxide insufflation, on the different physiological functions in order to prevent or to treat the side effects or complications which may occur in laparoscopic surgery. The major data from literature are confronted with the practical knowledge from a group of anesthetists with large experience in gynecological laparoscopic surgery.

Morphine microinjected into the nucleus raphe magnus does not block the activity of spinal trigeminal nucleus oralis convergent neurons in the rat

This study investigated the effects of morphine microinjection into the nucleus raphe magnus (RMg) on electrically evoked C-fiber activities of convergent neurons in the spinal trigeminal nucleus oralis (Sp5O), in halothane-anesthetized rats. Although the neurons could be depressed by systemic morphine (6 mg/kg, i.v.) in a naloxone-reversible fashion, morphine microinjected into the RMg (2. 5 microgram or 5 microgram) neither depressed their C-fiber-evoked responses, nor the diffuse noxious inhibitory controls acting on them. It is concluded that the RMg is not involved in reinforcing descending inhibitory controls that are tonic or triggered by noxious stimuli acting on Sp5O convergent neurons.

Morphine administered in the substantia gelatinosa of the spinal trigeminal nucleus caudalis inhibits nociceptive activities in the spinal trigeminal nucleus oralis

The present study investigates the effects of morphine microinjection into the spinal trigeminal nucleus caudalis (Sp5C) or the spinal trigeminal nucleus oralis (Sp5O) on C-fiber-evoked activities of Sp5O convergent neurons, after supramaximal percutaneous electrical stimulation in halothane-anesthetized rats. When it was microinjected into the Sp5O, morphine (2.5 microg in 0. 25 microl) never depressed the C-fiber-evoked responses of Sp5O convergent neurons (n = 13), whereas these neurons were responsive to the inhibitory effects of systemic morphine (6 mg/kg, i.v.) in a naloxone-reversible manner. On the contrary, morphine microinjected into the Sp5C produced a naloxone-reversible inhibition of the C-fiber-evoked responses of Sp5O neurons (n = 14). The magnitude and the time course of this effect varied according to the location of the injection sites. After microinjection into the superficial laminae (n = 7), a strong depressive effect of morphine (7 +/- 5% of control) on the C-fiber-evoked responses was apparent as soon as 5 min after the injection and could always be reversed by naloxone, administered either intravenously (0.4 mg/kg) or locally (2.5 microg in 0.6 microl) at the same site as morphine. After microinjection into deeper laminae (V-VI), a significant depressive effect (34 +/- 5% of control) of morphine could be detected only 20 min after the injection and was reversed only by intravenous administration of naloxone. These results suggest that morphine exerts its antinociceptive action on Sp5O convergent neurons by blocking the C-fiber inputs that relay in the Sp5C substantia gelatinosa. The mechanisms that underlie the activation of Sp5O convergent neurons by C-fibers and the inhibition of C-fiber-evoked responses of Sp5O convergent neurons by morphine microinjected into the Sp5C are discussed.