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Biomedical subjects

Marcel Chauvin

Publications and source records attributed to Marcel Chauvin.

16 recordsLinked to original sources
PubMed2006

Reduction of paracetamol metabolism after hepatic resection.

INTRODUCTION: Paracetamol is often used as an analgesic following hepatic resection. During liver resection, vascular clamping is carried out to reduce blood loss. Previous studies have described transient postoperative rises in serum aminotransferase levels and decreases in prothrombin time and factor V levels. We have examined paracetamol metabolism after liver resection. METHODS: A prospective observational study was performed. All patients undergoing liver resection were included. Propacetamol was given every 6 h. Blood samples for plasma paracetamol concentrations were collected before, 1 h after the end of the first injection (T1), just before the second injection (6 h: T6), and just before the fifth injection (24 h: T24). RESULTS: 37 patients were recruited. 13 had hepatic vascular exclusion (HVE group), 13 had portal triad clamping (PTC group) and 11 had abdominal surgery with no liver resection (NLR group: control group). At T6, the plasma paracetamol concentration in the HVE group was significantly higher than in the NLR groups; at T24, this concentration was significantly higher in the HVE group than in the NLR and PTC groups, and was higher in the PTC group than in the NLR group. Prothrombin time and factor V was significantly lower in the HVE group than in the PTC group on the first postoperative day. DISCUSSION: This study showed a reduction of paracetamol metabolism in the liver resection group with significantly increased paracetamol levels. However, the maximum mean plasma concentration reached was not clinically or toxicologically significant. For these reasons, we cannot suggest that paracetamol should or should not be avoided in patients undergoing liver resection.

Acetaminophen↗
PubMed2006

Cardiac function during intraperitoneal CO2 insufflation for aortic surgery: a transesophageal echocardiographic study.

The effect of laparoscopy on cardiac function is controversial. We hypothesized that cardiac dysfunction related to increased afterload could be predominant in patients undergoing elective abdominal aortic repair. To test this hypothesis, we conducted a transesophageal echocardiographic study in 15 patients during laparoscopic aortic surgery. We systematically assessed left ventricular (LV) and right ventricular (RV) functions. Measurements were obtained in the supine position without pneumoperitoneum and with an intraabdominal pressure of 14 mm Hg. Then, patients were turned to the right lateral position without pneumoperitoneum and intraabdominal pressure was increased to 7 mm Hg and to 14 mm Hg. Pneumoperitoneum induced a 25% arterial blood pressure increase and a 38% increase in LV systolic wall stress. A 25% decrease in LV ejection fraction and an 18% decrease in LV stroke volume were observed, associated with an increase in LV end-systolic volume. LV diastolic function impairment was observed without change in LV end-diastolic volume. Respiratory alterations in superior vena cava diameter were never observed, suggesting that volume status remained optimal. Respiratory changes in RV stroke volume were increased according to intraabdominal pressure and body position, reflecting an increase in RV afterload. In conclusion, peritoneal CO2 insufflation in patients scheduled for laparoscopic aortic surgery could impair LV and RV systolic functions as a consequence of increased afterload.

Adult↗
PubMed2006

A single preoperative dose of gabapentin (800 milligrams) does not augment postoperative analgesia in patients given interscalene brachial plexus blocks for arthroscopic shoulder surgery.

BACKGROUND: Inadequate analgesia is common after shoulder arthroscopy. Both interscalene blocks and gabapentin are effective methods of pain management under various circumstances. We tested the hypothesis that gabapentin augments postoperative analgesia provided by interscalene brachial plexus block in patients having ambulatory arthroscopic shoulder surgery. METHODS: Sixty patients were randomly assigned to receive oral gabapentin, 800 mg, or placebo 2 h before surgery. An interscalene brachial plexus block with 0.3 mL/kg of 0.5% ropivacaine was performed. General anesthesia was maintained with sevoflurane and included a single 1-microg/kg dose of remifentanil. Postoperative analgesia was initially provided with morphine and subsequently with ketoprofene (150 mg orally twice daily) and a combination of 400 mg acetaminophen and 30 mg dextropropoxyphene as needed. Pain scores, analgesic requirements, and side effects were assessed in the ambulatory unit and at home for 48 h. RESULTS: Emergence from general anesthesia was similar in both groups. There were no significant differences in pain scores, first postoperative request for analgesia, or oral analgesic consumption. The incidence of side effects was comparable in both groups, except that headaches were less frequent in the gabapentin group. CONCLUSION: A single preoperative dose of gabapentin (800 mg) does not augment postoperative analgesia in patients given interscalene brachial plexus blocks for arthroscopic shoulder surgery.

Adult↗
PubMed2005

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↗
PubMed2005

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↗
PubMed2005

Nefopam and ketamine comparably enhance postoperative analgesia.

Opioids alone sometimes provide insufficient postoperative analgesia. Coadministration of drugs may reduce opioid use and improve opioid efficacy. We therefore tested the hypothesis that the administration of ketamine or nefopam to postoperative patients with pain only partly alleviated by morphine reduces the amount of subsequent opioid necessary to produce adequate analgesia. Patients (n=77) recovering from major surgery were given up to 9 mg of IV morphine. Those who still had pain were randomly assigned to blinded administration of 1) isotonic saline (control group; n=21), 2) ketamine 10 mg (ketamine group; n=22), or 3) nefopam 20 mg (nefopam group; n=22). Three-milligram morphine boluses were subsequently given at 5-min intervals until adequate analgesia was obtained, until 60 min elapsed after the beginning of study drug administration, or until ventilation became insufficient (respiratory rate <10 breaths/min or saturation by pulse oximetry <95%). Supplemental morphine (i.e., after test drug administration) requirements were significantly more in the control group (mean +/- sd; 17 +/- 10 mg) than in the nefopam (10 +/- 5 mg; P <0.005) or ketamine (9 +/- 5 mg; P <0.001) groups. Morphine titration was successful in all ketamine and nefopam patients but failed in four control patients (two because of respiratory toxicity and two because of persistent pain). Tachycardia and profuse sweating were more frequent in patients given nefopam, and sedation was more intense with ketamine; however, the incidence of other potential complications did not differ among groups.

Adolescent↗
PubMed2005

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↗
PubMed2005

Preoperative gabapentin decreases anxiety and improves early functional recovery from knee surgery.

Gabapentin has antihyperalgesic and anxiolytic properties. We thus tested the hypothesis that premedication with gabapentin would decrease preoperative anxiety and improve postoperative analgesia and early postoperative knee mobilization in patients undergoing arthroscopic anterior cruciate ligament repair under general anesthesia. Forty patients were randomly assigned to receive 1200 mg oral gabapentin or placebo 1-2 h before surgery; anesthesia was standardized. Patients received morphine, 0.1 mg/kg, 30 min before the end of surgery and postoperatively via a patient-controlled pump. Pain scores and morphine consumption were recorded over 48 h. Degrees of active and passive knee flexion and extension were recorded during physiotherapy on days 1 and 2. Preoperative anxiety scores were less in the gabapentin than control group (visual analog scale scores of 28 +/- 16 mm versus 66 +/- 15 mm, respectively; P < 0.001). The gabapentin group required less morphine than the control group (29 +/- 22 mg versus 69 +/- 40 mg, respectively; P < 0.001). Visual analog scale pain scores at rest and after mobilization were significantly reduced in the gabapentin group. First and maximal passive and active knee flexions at 24 and 48 h were significantly more extensive in the gabapentin than in the control group. In conclusion, premedication with 1200 mg gabapentin improved preoperative anxiolysis, postoperative analgesia, and early knee mobilization after arthroscopic anterior cruciate ligament repair.

Adult↗
PubMed2004

Nefopam, a nonsedative benzoxazocine analgesic, selectively reduces the shivering threshold in unanesthetized subjects.

BACKGROUND: The analgesic nefopam does not compromise ventilation, is minimally sedating, and is effective as a treatment for postoperative shivering. The authors evaluated the effects of nefopam on the major thermoregulatory responses in humans: sweating, vasoconstriction, and shivering. METHODS: Nine volunteers were studied on three randomly assigned days: (1) control (saline), (2) nefopam at a target plasma concentration of 35 ng/ml (low dose), and (3) nefopam at a target concentration of 70 ng/ml (high dose, approximately 20 mg total). Each day, skin and core temperatures were increased to provoke sweating and then reduced to elicit peripheral vasoconstriction and shivering. The authors determined the thresholds (triggering core temperature at a designated skin temperature of 34 degrees C) by mathematically compensating for changes in skin temperature using the established linear cutaneous contributions to control of each response. RESULTS: Nefopam did not significantly modify the slopes for sweating (0.0 +/- 4.9 degrees C. microg-1. ml; r2 = 0.73 +/- 0.32) or vasoconstriction (-3.6 +/- 5.0 degrees C. microg-1. ml; r2 = -0.47 +/- 0.41). In contrast, nefopam significantly reduced the slope of shivering (-16.8 +/- 9.3 degrees C. microg-1. ml; r2 = 0.92 +/- 0.06). Therefore, high-dose nefopam reduced the shivering threshold by 0.9 +/- 0.4 degrees C (P < 0.001) without any discernible effect on the sweating or vasoconstriction thresholds. CONCLUSIONS: Most drugs with thermoregulatory actions-including anesthetics, sedatives, and opioids-synchronously reduce the vasoconstriction and shivering thresholds. However, nefopam reduced only the shivering threshold. This pattern has not previously been reported for a centrally acting drug. That pharmacologic modulations of vasoconstriction and shivering can be separated is of clinical and physiologic interest.

Adult↗
PubMed2004

Quality control programme for acute pain management in emergency medicine: a national survey.

OBJECTIVE: This national survey was carried out to evaluate the quality programme for acute pain management in the emergency department (ED) and in pre-hospital emergency medical services (EMS). METHODS: Two types of questionnaires were sent to the chief consultant and the chief nurse of all ED and EMS. Data collected were: the type of structure, quality programme organization, acute pain management, and the training needs to initiate a pain quality programme. RESULTS: A total of 363 questionnaires were recorded (198 from chief consultants) with 98% of questionnaires being usable. A pain management committee existed in 71% of cases, a quality committee in 83%. A complete quality control procedure existed in 53% of units. An audit on pain management was carried out in only 23% of cases. Training in quality was performed for 64% of physicians and 68% of nurses. Training specifically for pain management was carried out for physicians in 56% of cases and for nurses in 68% of cases. Pain therapeutics protocols existed in 69% of cases. Pain intensity was evaluated 'systematically or often' in 64% at the beginning of patient management, and in 56% at the end of patient management. The staff was 'not very motivated' for a pain management quality programme in less than 3% of responses. A total of 61% of chief consultants and 58% of chief nurses requested advice. CONCLUSION: Most ED and EMS units seem to master the quality control programme methodology. Units are highly motivated to initiate a quality control programme on pain. Nevertheless, its implementation could benefit from some external support.

Acute Disease↗
PubMed2003

'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↗
PubMed2002

Mild hypothermia does not increase bacterial proliferation on implanted vascular grafts.

BACKGROUND: Mild hypothermia may offer protection against spinal cord ischemia during aortic surgery. However, hypothermia also promotes postoperative infection via two mechanisms: peripheral vasoconstriction and impairment of various immune functions. If mild hypothermia aggravates graft infections, immune function impairment would presumably be the most important factor because thermoregulatory vasoconstriction does not appreciably reduce aortic blood flow. We therefore tested the hypothesis that resistance to vascular graft infection is not reduced by mild perioperative hypothermia in dogs. METHODS: After colonization with a solution of Staphylococcus epidermidis, prostheses were used to replace the infrarenal aorta in 20 dogs. During surgery, the dogs were randomly assigned to maintain of normothermia or passive cooling. Seven days later, grafts were recovered for bacteriologic study. RESULTS: Colony counts for the grafts removed from the normothermic and hypothermic dogs did not differ significantly. CONCLUSIONS: Mild perioperative hypothermia does not increase proliferation of S epidermidis on aortic vascular grafts.

Animals↗
PubMed2002

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↗
PubMed2002

The role of ketamine in preventing fentanyl-induced hyperalgesia and subsequent acute morphine tolerance.

UNLABELLED: Perioperative opioids increase postoperative pain and morphine requirement, suggesting acute opioid tolerance. Furthermore, opioids elicit N-methyl-D-aspartate (NMDA)-dependent pain hypersensitivity. We investigated postfentanyl morphine analgesic effects and the consequences of NMDA-receptor antagonist (ketamine) pretreatment. The rat nociceptive threshold was measured by the paw-pressure vocalization test. Four fentanyl boluses (every 15 min) elicited a dose-dependent (a) increase followed by an immediate decrease of the nociceptive threshold and (b) reduction of the analgesic effect of a subsequent morphine administration (5 mg/kg): -15.8%, -46.6%, -85.1% (4 x 20, 4 x 60, 4 x 100 microg/kg of fentanyl, respectively). Ketamine pretreatment (10 mg/kg) increased the fentanyl analgesic effect (4 x 60 microg/kg), suppressed the immediate hyperalgesic phase, and restored the full effect of a subsequent morphine injection. Fentanyl also elicited a delayed dose-dependent long-lasting decrease of the nociceptive threshold (days) that was prevented by a single ketamine pretreatment before fentanyl. However, a morphine administration at the end of the fentanyl effects restored the long-lasting hyperalgesia. Repeated ketamine administrations were required to obtain a complete preventive effect. Although ketamine had no analgesic effect per se at the dose used herein, our results indicate that sustained NMDA-receptor blocking could be a fruitful therapy for improving postoperative morphine effectiveness. IMPLICATIONS: Fentanyl-induced analgesia is followed by early hyperalgesia (hours), acute tolerance to the analgesic effects of morphine, and long-lasting hyperalgesia (days). All these phenomena are totally prevented by repeated administrations of the NMDA-receptor antagonist, ketamine, simultaneously with fentanyl and morphine administration.

Analgesics, Opioid↗
PubMed2002

Supplementing desflurane-remifentanil anesthesia with small-dose ketamine reduces perioperative opioid analgesic requirements.

UNLABELLED: Relative large-dose intraoperative remifentanil could lead to the need for more postoperative analgesics. Intraoperative N-methyl-D-aspartate receptor antagonists, such as ketamine, decrease postoperative opioid use. We therefore tested the hypothesis that intraoperative small-dose ketamine improves postoperative analgesia after major abdominal surgery with remifentanil-based anesthesia. Fifty patients undergoing abdominal surgery under remifentanil-based anesthesia were randomly assigned to intraoperative ketamine or saline (control) supplementation. The initial ketamine dose of 0.15 mg/kg was followed by 2 microg. kg(-1). min(-1). In both groups, desflurane was kept constant at 0.5 minimum alveolar anesthetic concentration without N(2)O, and a remifentanil infusion was titrated to autonomic responses. All patients were given 0.15 mg/kg of morphine 30 min before the end of surgery. Pain scores and morphine consumption were recorded for 24 postoperative h. Less of the remifentanil was required in the Ketamine than in the Control group (P < 0.01). Pain scores were significantly larger in the Control group during the first 15 postoperative min but were subsequently similar in the two groups. The Ketamine patients required postoperative morphine later (P < 0.01) and received less morphine during the first 24 postoperative h: 46 mg (interquartile range, 34-58 mg) versus 69 mg (interquartile range, 41-87 mg, P < 0.01). No psychotomimetic symptoms were noted in either group. In conclusion, supplementing remifentanil-based anesthesia with small-dose ketamine decreases intraoperative remifentanil use and postoperative morphine consumption without increasing the incidence of side effects. Thus, intraoperative small-dose ketamine may be a useful adjuvant to intraoperative remifentanil. IMPLICATIONS: Supplementing remifentanil-based anesthesia with small-dose ketamine decreased intraoperative remifentanil use and postoperative morphine consumption. These data demonstrate that N-methyl-D-aspartate antagonists, such as ketamine, can be a useful adjuvant to intraoperative remifentanil.

Adjuvants, Anesthesia↗