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Biomedical subjects

Dominique Fletcher

Publications and source records attributed to Dominique Fletcher.

9 recordsLinked to original sources

Paradoxical reaction to epinephrine induced by beta-blockers in an anaphylactic shock induced by penicillin.

Increased risk of severe and resistant anaphylactic shock is a rare and not widely known adverse effect of beta-blocker treatment. It is illustrated in a case of refractory anaphylactic shock occurring in a 47-year-old woman who received beta-blockers. Actually, beta-blockers increase the release of anaphylactic mediators, decrease the cardiovascular compensatory changes to the anaphylactic shock and promote paradoxical reflex vagotonic effects when using epinephrine.

Adrenergic beta-Agonists↗

The effect of nefopam on morphine overconsumption induced by large-dose remifentanil during propofol anesthesia for major abdominal surgery.

Opioids may activate pain facilitatory systems opposing analgesia. We investigated whether large-dose remifentanil given during IV anesthesia caused postoperative morphine overconsumption and whether nefopam (a centrally acting analgesic) could reduce this. Sixty patients scheduled for abdominal surgery were included in this prospective, randomized study. The first 30 patients received either small-dose (Group S: 3 ng/mL) or large-dose (Group L: 8 ng/mL) remifentanil administrated by a target-controlled infusion during propofol anesthesia. Before skin closure, patients received morphine 0.15 mg/kg. Another 30 patients also received nefopam 20 mg intraoperatively. Postoperative pain was controlled by titration of morphine, followed by patient-controlled morphine analgesia (PCA). Morphine was requested earlier in Group L than in Group S (10 [1-63] min versus 37 [5-90] min, median [range]; P < 0.002). The dose of morphine by titration was larger in Group L than in Group S (0.28 [0.04-0.38] mg/kg versus 0.16 [0.03-0.41] mg/kg; P < 0.05). PCA morphine consumption and pain scores were similar. There were no differences between the nefopam groups in the time to first morphine request or in the dose of morphine by titration. Postoperative morphine overconsumption occurred after large-dose remifentanil and propofol anesthesia during the early postoperative period. Pretreatment with nefopam could be useful to prevent pain sensitization induced by opioids.

Adult↗

Details of the initial management of cardiac arrest occurring in the workplace in a French urban area.

INTRODUCTION: Our goal was to evaluate the details and management of cardiac arrest (CA) occurring in the working environment. MATERIALS AND METHODS: We conducted a 10-year retrospective study based on the medical records of the Garches mobile intensive care unit. CA occurring in the workplace ("Inside W." group) was matched with two CA outside the workplace ("Outside W." group), with regard to sex, age and year of occurrence. The Chain of Survival and prognosis factors were analysed in a bi-multivariate analysis. RESULTS: From 1993 to 2002, 72 CA were included in the "Inside W." group, with 79% arising from suspected cardiac aetiology (there was a similar proportion in the "Outside W." group). Some variables in the cardiac aetiology patients were higher in the "Inside W." group compared to the "Outside W." group (P < 0.05): early external chest compression [(ECC), 37%, n = 20 versus 16%, n = 16)] and ventricular fibrillation as initial recorded rhythm (40%, n = 33 versus 16%, n = 16). The proportion of use of automated external defibrillator (AED) was similar in the two groups. The workplace was not associated with a better outcome, with 9% patients discharged alive compared to 4% n = 6, P > 0.05. Early ECC and defibrillation attempted with an AED were associated with patients discharged alive from the intensive care unit in a multivariate analysis (P < 0.05), but not the workplace and cardiac aetiology. CONCLUSION: Although our study did not support that concept that the workplace was a safer place, there was a better chain of survival for CA applied within workplace settings. Basic Life Support teaching and installation of AEDs could be helpful, though further cost-effectiveness studies are needed.

Adult↗

Remifentanil-induced postoperative hyperalgesia and its prevention with small-dose ketamine.

BACKGROUND: Remifentanil-induced secondary hyperalgesia has been documented experimentally in both animals and healthy human volunteers, but never clinically. This study tested the hypotheses that increased pain sensitivity assessed by periincisional allodynia and hyperalgesia can occur after relatively large-dose intraoperative remifentanil and that small-dose ketamine prevents this hyperalgesia. METHODS: Seventy-five patients undergoing major abdominal surgery were randomly assigned to receive (1) intraoperative remifentanil at 0.05 microg x kg(-1) x min(-1) (small-dose remifentanil); (2) intraoperative remifentanil at 0.40 microg x kg(-1) x min(-1) (large-dose remifentanil); or (3) intraoperative remifentanil at 0.40 microg x kg(-1) x min(-1) and 0.5 mg/kg ketamine just after the induction, followed by an intraoperative infusion of 5 microg x kg(-1) x min(-1) until skin closure and then 2 microg x kg(-1) x min(-1) for 48 h (large-dose remifentanil-ketamine). Pain scores and morphine consumption were recorded for 48 postoperative hours. Quantitative sensory tests, peak expiratory flow measures, and cognitive tests were performed at 24 and 48 h. RESULTS: Hyperalgesia to von Frey hair stimulation adjacent to the surgical wound and morphine requirements were larger (P < 0.05) and allodynia to von Frey hair stimulation was greater (P < 0.01) in the large-dose remifentanil group compared with the other two groups, which were comparable. There were no significant differences in pain, pressure pain detection threshold with an algometer, peak flow, cognitive tests, or side effects. CONCLUSION: A relatively large dose of intraoperative remifentanil triggers postoperative secondary hyperalgesia. Remifentanil-induced hyperalgesia was prevented by small-dose ketamine, implicating an N-methyl-d-aspartate pain-facilitator process.

Adult↗

Small-dose ketamine infusion improves postoperative analgesia and rehabilitation after total knee arthroplasty.

We designed this study to evaluate the effect of small-dose IV ketamine in combination with continuous femoral nerve block on postoperative pain and rehabilitation after total knee arthroplasty. Continuous femoral nerve block was started with 0.3 mL/kg of 0.75% ropivacaine before surgery and continued in the surgical ward for 48 h with 0.2% ropivacaine at a rate of 0.1 mL . kg(-1) . h(-1). Patients were randomly assigned to receive an initial bolus of 0.5 mg/kg ketamine followed by a continuous infusion of 3 mug . kg(-1) . min(-1) during surgery and 1.5 mug . kg(-1) . min(-1) for 48 h (ketamine group) or an equal volume of saline (control group). Additional postoperative analgesia was provided by patient-controlled IV morphine. Pain scores and morphine consumption were recorded over 48 h. The maximal degree of active knee flexion tolerated was recorded daily until hospital discharge. Follow-up was performed 6 wk and 3 mo after surgery. The ketamine group required significantly less morphine than the control group (45 +/- 20 mg versus 69 +/- 30 mg; P < 0.02). Patients in the ketamine group reached 90 degrees of active knee flexion more rapidly than those in the control group (at 7 [5-11] versus 12 [8-45] days, median [25%-75% interquartile range]; P < 0.03). Outcomes at 6 wk and 3 mo were similar in each group. These results confirm that ketamine is a useful analgesic adjuvant in perioperative multimodal analgesia with a positive impact on early knee mobilization. No patient in either group reported sedation, hallucinations, nightmares, or diplopia, and no differences were noted in the incidence of nausea and vomiting between the two groups.

Aged↗

'Boussignac' continuous positive airway pressure system: practical use in a prehospital medical care unit.

Continuous positive airway pressure in acute cardiogenic pulmonary edema is rarely used by prehospital emergency care units, because of the particular technical drawbacks of existing equipment. The aim of this one year prospective descriptive open study without a control group was to assess the technical feasibility of using the Boussignac continuous positive airway pressure system (Vygon) in a prehospital medical care service. Statistical comparisons were performed using Student's t-test or a Wilcoxon T-test. There were 57 decisions to use continuous positive airway pressure. Seven records were excluded. Four patients were intubated on the scene and six within one hour after hospital admission. The respiratory rate and transcutaneous oxygen saturation improved significantly for all of the other patients (Student's t-test P < 0.001). The Boussignac continuous positive airway pressure system has many advantages, including flexibility and pressure monitoring, lower oxygen consumption, and ease of use. These should allow this technique to be used more widely by prehospital teams.

Aged↗

Interaction of a combination of morphine and ketamine on the nociceptive flexion reflex in human volunteers.

Experimental studies in animals have suggested that a combination of morphine and N-methyl-D-aspartate (NMDA) receptor antagonists may have additive or synergistic analgesic effects. To further study the nature of the interaction between these two classes of analgesic agents, we analyzed the effects of morphine, ketamine and their combination on electrophysiological recordings of the nociceptive flexion RIII reflex in 12 healthy volunteers. Morphine (0.1 mg/kg), ketamine (0.1 mg/kg followed by 4 microg/kg/min) or their combination were administered intravenously according to a double-blind, placebo controlled and cross-over design. The RIII reflex was recorded from the biceps femoris and elicited by electrical stimulation of the sural nerve. The effects of the drugs were tested on: (1) the stimulus-response curves of the reflex up to the tolerance threshold (frequency of stimulation: 0.1Hz); (2) the progressive increase of the reflex and painful sensations (i.e. wind-up phenomenon) induced by a series of 15 electrical stimuli at a frequency of 1Hz (intensity: 20% above threshold). The stimulus-response curve of the nociceptive RIII reflex was significantly reduced after injection of a combination of ketamine and morphine, but was not modified when placebo or each of the active drugs was administered alone. The wind-up of the RIII reflex and painful sensation was not significantly altered after the injection of placebo, ketamine, morphine or their combination. In conclusion, the present electrophysiological results in humans demonstrate a synergistic interaction between morphine and ketamine, which tends to confirm the interest of using this type of combination in the clinical context. The differential effects observed on the recruitment curve and wind-up indicate, however, that the mechanisms of the interaction between opiates and NMDA receptor antagonists are not univocal but depend on the modality of activation of the nociceptive afferents.

Adult↗