Search PubMed⌕ Search

Biomedical subjects

M Pinaud

Publications and source records attributed to M Pinaud.

At least 55 records · Page 3Linked to original sources
PubMed1997

A novel supraclavicular approach to brachial plexus block.

We describe a novel supraclavicular approach to the brachial plexus. Designated as the intersternocleidomastoid technique, this new approach was tested in unembalmed cadavers. It was then applied for evaluation to 150 ASA grade I or II patients scheduled for elective surgery or physiotherapy of the upper limb or for treatment of reflex sympathetic dystrophy associated with painful shoulder. The new approach was easy to master because of a very simple surface landmark, i.e., the triangle formed by the sternocleidomastoid heads, which were visible and palpable in most patients studied (90%). The procedure was effective intraoperatively, providing satisfactory anesthesia in 140 patients (93%), partially satisfactory blocks in 6 (4%), and unsatisfactory blocks in only 4 (3%). The catheter entry point is cephalad enough not to obscure the surgical field on the shoulder. Catheter insertion was successful in 63 of 70 patients. Postoperative analgesia was provided for 48 h or more in 45 patients and for 24 h in 18 patients. Only minor complications were observed: asymptomatic phrenic nerve block in 89 patients (60%), transient Horner's syndrome in 15 (10%), transient recurrent laryngeal nerve blockade in 2, and misplacement of the catheter into the subclavian vein in 1 patient. No pneumothorax was observed.

Adult↗
PubMed1997

The effects of a nonsteroidal antiinflammatory drug (ketoprofen) on morphine respiratory depression: a double-blind, randomized study in volunteers.

Nonsteroidal antiinflammatory drugs (NSAIDs) decrease the postoperative requirements for opioid analgesic medication. To determine whether NSAIDs potentiate the respiratory effects of opioids, we studied the effects of ketoprofen (K), an NSAID, on respiratory depression induced by morphine (M) in volunteers. After ethics committee approval, 12 healthy male volunteers received infusions of K (1.5 mg/kg), M (0.1 mg/ kg), and KM (1.5 mg/kg + 0.1 mg/kg) in a double-blind, randomized, three-treatment, three-period cross-over trial. During the three sessions, CO2 rebreathing challenges for ventilatory and occlusion pressure responses to CO2 were performed immediately before and 10, 70, 130, 190, and 250 min after drug infusion over 10 min. Venous blood samples for plasma drug concentrations were withdrawn at the same times. Comparisons were made on slopes of ventilatory and occlusion pressure responses to CO2. Venous blood samples confirmed that morphine plasma concentrations were similar when subjects had received morphine alone and when they had received the combination of drugs. Morphine alone induced a respiratory depression with a decrease in both ventilatory and occlusion pressure responses to CO2. Ketoprofen alone did not produce any respiratory effects. The combination of drugs induced a decrease in ventilatory responses to CO2, but intergroup comparisons showed that this was significantly less marked than the decrease induced by morphine alone. In conclusion, for similar morphine plasma concentrations, respiratory depression was less marked with the combination of drugs than with morphine alone. Therefore, ketoprofen may reduce the respiratory depression induced by morphine.

Adult↗
PubMed1997

Neurotoxicological assessment after intracisternal injection of liposomal bupivacaine in rabbits.

UNLABELLED: Experiments were performed on rabbits randomly assigned to intracisternally receive 0.3 mL of plain bupivacaine 5 mg/mL, liposomal bupivacaine 5 mg/mL, bupivacaine-free liposomes, or isotonic phosphate-buffered saline. Mechanical ventilation was initiated or intravenous dopamine was infused when respiratory depression or hypotension occurred. Seven days after the injection, the whole spinal cord was removed and histopathologic characteristics were studied on transverse sections. All preparations were devoid of phosphatidylcholine hydrolysis or oxidation compounds. Solutions without bupivacaine produced transient irritative signs that required sedation in most rabbits. Despite the similar duration of respiratory depression in groups receiving liposomal or plain bupivacaine, liposomes produced significantly prolonged motor blockade (126 vs 70 min). Correction of hypotension after plain bupivacaine required a longer dopamine infusion and larger doses than after liposomal bupivacaine (28 vs 18 min and 74 vs 47 mg). Necrosis was observed in the cervical area of two rabbits (one in the liposomal bupivacaine group and another in the phosphate buffer group). No demyelinated areas were noted in spinal cord examinations. We conclude that liposomal bupivacaine leads to a less severe sympathetic block and to a prolonged motor block, whereas histologic changes are not significantly different among groups. IMPLICATIONS: Multilamellar liposomes containing bupivacaine administered intracisternally to rabbits produce spinal cord histopathologic changes not significantly different from those observed with plain bupivacaine. Sustained release of bupivacaine from liposomes is suggested by the prolonged motor blockade and the reduced severity of arterial hypotension. Use of these liposomes could prolong the local anesthetic effects of bupivacaine.

Anesthetics, Local↗
PubMed1996

[Neurotoxicity of intrathecally administrated agents].

Spinal anaesthetics can induce histopathologic lesions and regional haemodynamic alterations in the spinal cord. There are numerous causes of neurologic lesions, including direct trauma of the spinal cord and nerve roots during puncture or catheter insertion, compromised spinal cord perfusion and direct neurotoxic effect. Histopathologic lesions are localized either in meninges (meningitis or arachnoiditis) or in neuraxis (myelitis or axonal degeneration). Neurotoxicity can result from decrease in neuronal blood supply, elicited by high concentrations of the solutions, long duration exposure to local anaesthetics, and the use of adjuvants. They have been implicated in the occurrence of cauda equina syndrome after continuous spinal anaesthesia using hyperbaric solution of lidocaine and tetracaine given through small diameter catheters. Selective spinal analgesia is induced by spinal opioids without motor blockade except for meperidine. Complications occurred in patients after high doses of morphine, which were related to one of its metabolites, morphine-3-glucuronide. Preservative-free opioid solutions are to be preferred for spinal anaesthesia. There is no report of neurotoxicity neither in animal studies, nor in humans, using spinal clonidine. In order to reduce the incidence of neurotoxicity, some safety rules should be followed. The lowest efficient dose of local anaesthetics must be given. Incomplete blockade should not necessarily lead to a reinjection. Large volume of hyperbaric lidocaine or repeated injections of such solutions must be avoided as well as preservative-containing solutions. The administration of new compounds by the spinal route must be supported by data of spinal neuropharmacology and the lack of neurotoxicity must have been previously checked with animal studies.

Analgesics, Opioid↗
PubMed1996

[Preoperative evaluation of coronary circulation].

To define a strategy for coronary circulation assessment is a difficult task as most of the studies have been carried out in vascular surgery, as some of them are controversial, and as no test has a 100% sensitivity and specificity. However patients with high perioperative risk of cardiac events have to be identified, in order to intensify medical treatment or to consider myocardial revascularisation. A first evaluation is based on history, physical examination and simple tests, such as rest electrocardiogram and thorax X-Ray. Additional tests are not required when surgery does not elicit a major activity of the cardiocirculatory system. Postoperative cardiac risk is low when none of the nine risk factors defined by Goldman and/or coronary insufficiency (residual angina elicited by minor physical activity, unstable angina, myocardial infarction) are present. The problem remains in patients with Goldman risk factors and/or at risk of coronary artery disease because of diabetes mellitus, heavy smoking, hypercholesterolaemia, arterial hypertension, undergoing major abdominal, thoracic or vascular surgery. Preoperative electrocardiographic Holter monitoring is still of value, especially in patients with known or supposed ischaemic heart disease and unable to make a physical effort. A poor exercise capacity and changes in electrocardiographic stress testing are factors of poor prognosis. The dobutamine stress echocardiography has a good sensitivity and specificity when an effort test cannot be performed. The value of dipyridamole-thallium 201 scintigraphy could be improved by a quantitative analysis of the number of affected segments and territories. Patients with angina or ischaemic episodes on continuous electrocardiogram, or with dobutamine echocardiography kinetic disturbances and with stress myocardic scintigraphy or stress exercise testing abnormalities could undergo a coronarography, in order to consider myocardic revascularization prior to surgery.

Coronary Angiography↗
PubMed1996

Ketamine and norketamine plasma concentrations after i.v., nasal and rectal administration in children.

It has been suggested that nasal administration of ketamine may be used to induce anaesthesia in paediatric patients. We have examined the pharmacokinetics of ketamine and norketamine after nasal administration compared with rectal and i.v. administration in young children. During halothane anaesthesia, 32 children, aged 2-9 yr, weight 10-30 kg, were allocated randomly to receive ketamine 3 mg kg-1 nasally (group IN3) or ketamine 9 mg kg-1 nasally (group IN9); ketamine 9 mg kg-1 rectally (group IR9); or ketamine 3 mg kg-1 i.v. (group IV3). Venous blood samples were obtained before and up to 360 min after administration of ketamine. Plasma concentrations of ketamine and norketamine were measured by gas liquid chromatography. Statistical comparisons were performed using ANOVA and the Kruskall-Wallis test, with P < 0.05 as significant. Mean plasma concentrations of ketamine peaked at 496 ng ml-1 in group IN3 within 20 min, 2104 ng ml-1 in group IN9 within 21 min, and 632 ng ml-1 in group IR9 within 42 min. Plasma concentrations of norketamine peaked at approximately 120 min after nasal ketamine, but appeared more rapidly after rectal administration of ketamine and were always higher than ketamine concentrations in the same situation. Calculated bioavailability was 0.50 in groups IN3 and IN9 and 0.25 in group IR9. We conclude that nasal administration of low doses of ketamine produced plasma concentrations associated with analgesia, but using high doses via the nasal route produced high plasma concentrations of ketamine similar to those that induce anaesthesia. However, the large volume of ketamine required was partly swallowed and led to an unacceptable variability of effect that precludes this route for induction of anaesthesia.

Administration, Intranasal↗
PubMed1996

Pharmacodynamic dose-response and safety study of cisatracurium (51W89) in adult surgical patients during N2O-O2-opioid anesthesia.

After administration of doses ranging from 0.025 to 0.25 mg/kg, the neuromuscular blocking effect of cisatracurium was assessed in 119 adult surgical patients receiving N2O-opioid-midazolam-thiopental anesthesia. The calculated 95% effective dose (ED95) for inhibition of adductor pollicis twitch evoked at 0.1 Hz was 0.053 mg/kg. With 0.10 mg/kg injected over 5-10 and 20-30 s, median onset times (range) were 5.8 (3.0-7.7) and 4.8 (1.2-10.2) min, respectively, and median times to 5% and 95% recovery (range) were 27 (19-46) and 48 (25-68) min, respectively. For doses of 0.10, 0.20, and 0.25 mg/kg, median 5%-95% and 25%-75% recovery indexes ranged from 48 to 90 min and 8 to 9 min, respectively. After administration of neostigmine (0.06 mg/kg) at 10%-15% or 16%-30% recovery, the median times to 95% recovery (range) were 6 (2-22) and 4 (2-5) min, respectively. There were no changes in heart rate, blood pressure, or plasma histamine concentrations during the first 5 min after administration of cisatracurium at doses up to 5 x ED95 injected over 5-10 s. No cutaneous flushing or bronchospasm was noted. In summary, cisatracurium is a potent neuromuscular blocking drug with an intermediate duration of action, characterized by excellent cardiovascular stability, with no apparent histamine release.

Adolescent↗
PubMed1995

Comparison between oxygen consumption calculated by Fick's principle using a continuous thermodilution technique and measured by indirect calorimetry.

We calculated oxygen consumption by the reverse Fick principle (cVO2) using cardiac output measured with a new technique of continuous thermal dilution and compared these values with measurements made at the same time using a gas exchange method (mVO2). We studied nine patients in a stable condition after cardiac surgery. In each patient six successive measurements of continuous cardiac output and mVO2 were made over 5 min at 10-min intervals. The mean difference between the estimates (mVO2-cVO2) was 15 ml min-1 m2 (95% confidence limits, -3 to 33 ml min-1 m2). The relative error of each method was 5% and 4% (continuous cardiac output and gas exchange methods, respectively). Calculation of VO2 using the new cardiac output technology had good repeatability compared with direct measurement, probably because of the high precision of measurement of cardiac output.

Aged↗
PubMed1995

A new axillary approach for continuous brachial plexus block. A clinical and anatomic study.

Catheter insertion in the neurovascular space by axillary approach allows a continuous brachial plexus block and/or postoperative analgesia. We developed a perivenous technique whereby the approach to the neurovascular sheath is guided under fluoroscopy by a preopacified axillary vein. A randomized study compared this technique to the technique of Selander in ASA grade I-II patients scheduled for surgery or painful physiotherapy of the hand. The study was performed in 36 patients randomly divided into two groups. In Group 1 (n = 18), the catheter was placed according to the technique described by Selander. In Group 2 (n = 18), the catheter was placed using our perivenous technique. A complete block was obtained in all the patients of Group 2 vs only 50% of the patients in Group 1 (P < 0.05). In Group 1 a partial block was observed in 17%, with failure in 33% of the patients. There was no difference in the two groups regarding the time required to perform either technique, the duration of the complete block, the pain score, or the amount of continuously administrated bupivacaine during the first 48 h postoperatively. The plasma concentrations of total bupivacaine (high-performance liquid chromatography) were low in successful blocks, with no differences in the two groups; the median value was 0.68 microgram/mL (95% confidence interval: 0.62-0.89). The concentrations were higher (P < 0.01) in failed blocks; the median value was 1.69 micrograms/mL (95% confidence interval: 0.58-2.8). A complementary anatomic study of three arms from fresh cadavers allowed verification of the correct localization of the Teflon cannula and flexible catheter, as well as homogeneous diffusion of the methylene blue inside the brachial plexus. The perivenous technique for continuous axillary brachial plexus block may improve the success rate due to its radiologic and accurate location of the neurovascular sheath.

Adult↗
PubMed1995

Premedication with midazolam in children. Effect of intranasal, rectal and oral routes on plasma midazolam concentrations.

We report a study performed to compare the time and plasma drug concentrations necessary to achieve a similar state of sedation after midazolam premedication given by various routes in children of 2-5 years old. Children were randomly allocated to one of three groups to receive midazolam 0.2 mg.kg-1 given intranasally, 0.5 mg.kg-1 given orally or 0.3 mg.kg-1 given rectally. Sedation was measured regularly until venepuncture was possible in a cooperative child. At this time, a first blood sample was taken to measure plasma concentration, followed by another 10 min later. Anaesthesia consisted of intravenous propofol supplemented with regional analgesia. At recovery from anaesthesia, a third blood sample was taken. Adequate sedation occurred sooner (7.7, SD 2.4 min) with intranasal than oral (12.5, SD 4.9 min) or rectal (16.3, SD 4.2 min) midazolam. The initial blood levels were lower when the drug was given by the alimentary routes despite higher doses (146, SD 51 ng.ml-1 in 11.5, SD 3.9 min; 104, SD 34 ng.ml-1 in 21 +/- 6 min; and 93, SD 63 ng.ml-1 in 23.1, SD 3.5 min for the intra nasal, rectal and oral routes respectively). Duration of surgical procedures, and of propofol infusion, and recovery from anaesthesia was similar for the three groups. The only problem arose in a 30-month-old boy in the intranasal group who developed respiratory depression with a plasma midazolam concentration of 169 ng.ml-1. Intranasal midazolam is an excellent alternative for rapid premedication provided that respiratory monitoring is used.

Administration, Intranasal↗
PubMed1994

[Comparison of cardiac output measured continuously by thermodilution and calculated according to Fick's principle].

Recently, a thermodilution technique for continuous measurement of cardiac output was introduced. The aim of this study was to evaluate the accuracy of continuous cardiac output measurement using the thermodilution technique (CCO) and to assess the correspondence between CCO and cardiac output obtained with the Fick's principle (Fick-CO). Nine patients were studied in the postoperative period after cardiac surgery. A new pulmonary artery catheter modified by attachment of a thermal filament (Intellicath, Model PA3-H-8Fr) was inserted and connected to a continuous cardiac output computer (Vigilance Monitor). Oxygen consumption was continuously measured using the gas exchange method (Deltatrac Metabolic Monitor). Fick-CO was calculated according to the Fick's principle. The study in each patient consisted of 6 serial determinations of both CCO and Fick-CO at 10 min intervals. For 54 pairs of measurements, the mean difference (Fick-CO-CCO) was 0,6 L.min-1. The limits of agreement were--0,6 to 1,8 L.min-1 respectively. The relative error was 6% for CCO and 10% for Fick-CO. It is concluded that CCO and Fick-CO cannot be considered as being interchangeable. However, the accuracy of CCO is acceptable. The technique does not require any user calibration and eliminates the need of bolus injections. Further studies are necessary to determine the benefits of this new technique in the various clinical situations.

Aged↗
PubMed1994

Ketoprofen for pain after hip and knee arthroplasty.

In a double-blind, randomized study, we have compared the effects of i.v. ketoprofen 200 mg followed by 12.5 mg h-1 over 13 h, with those of extradural morphine 4 mg in 32 patients after hip and knee arthroplasty. A visual analogue scale was used to score pain before analgesic administration (first complaint after operation), 1 h after and every 2 h subsequently. Pain reduction 1 h after the start of analgesia was mean 44% (SEM 17%) in the extradural morphine group and 54% (9%) in the ketoprofen group (ns). There were no significant differences between groups in pain scores, pain reduction and additional analgesia requirement (i.v. paracetamol). Naloxone 5 micrograms kg-1 h-1 was required for hypercapnia exceeding 6.0 kPa in three patients in the extradural morphine group (vs none in the ketoprofen group; ns). There were no differences between groups in side effects, except for urinary retention, which was more frequent in the extradural morphine group (P < 0.05). As there were few differences between i.v. ketoprofen and extradural morphine, we conclude that ketoprofen may be an efficient alternative to extradural morphine after hip and knee arthroplasty.

Adult↗
PubMed1994

Acute effects of urapidil on left ventricular function in hypertensive patients: comparison with clonidine using radionuclide angiography.

We have studied the effects of urapidil 0.4 mg kg-1 i.v. and clonidine 2.5 micrograms kg-1 i.v. on left ventricular volume and function in 20 patients with chronic coronary artery disease and essential hypertension. Patients were studied using 99mtechnetium radionuclide angiography with first-pass and ECG-gated equilibrium blood-pool techniques and non-invasive sphygmomanometry. Administration of both urapidil and clonidine caused a similar decrease in mean arterial pressure (20%), associated with an equivalent reduction in systemic vascular resistance. Despite the decrease in mean arterial pressure, heart rate did not change after administration of clonidine, but there was an early and transient increase of 13% after urapidil. There were no changes in cardiac index, but in contrast with clonidine, urapidil caused a decrease in stroke index. In both groups, global left ventricular ejection fraction did not change. Urapidil produced a mean decrease in end-diastolic volume of 8% and a mean decrease in end-systolic volume of 13%, in contrast with clonidine which caused little change. Reduced arterial pressure, systemic vascular resistance and preload after urapidil 0.4 mg kg-1 i.v., associated with lack of prolonged tachycardia and preserved global left ventricular performance, may have obvious clinical implications in anaesthesia.

Adrenergic alpha-Antagonists↗