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Biomedical subjects

F Bonnet

Publications and source records attributed to F Bonnet.

At least 91 records · Page 5Linked to original sources
PubMed1998

[Motor deficit of the lower limbs and urinary incontinence following peridural anesthesia].

Neurological complications of epidural anaesthesia are rare, but can be severe. We report the case of a 49-year-old man, with a history of non equilibrated diabetes, who experienced after an epidural anaesthesia for peripheral vascular surgery a polyneuropathy with muscle weakness of the lower extremities associated with a transient urinary incontinence. A spinal compression was excluded by computed tomography and magnetic resonance imaging. Electromyography showed an impaired nervous motor conduction. An aggravation of a pre-existing diabetic and alcoholic polyneuropathy, associated with possible spinal ischaemia of multifactorial origin could be the cause of these complications. This case emphasizes the importance, during preanesthetic assessment of candidates for epidural or spinal anaesthesia, to search for a possible unrecognized neuropathy at risk of aggravation by regional anaesthesia.

Alcoholism↗
PubMed1998

[Total spinal anesthesia after posterior lumbar plexus block].

We report a case of total spinal anaesthesia which occurred after a lumbar plexus block using a posterior approach. After total hip arthroplasty under general anaesthesia, a lumbar plexus block was performed according to Winnie's landmarks at the L4 interspace using a nerve stimulator. Aspiration test for blood and spinal fluid were both negative, as well as a test dose of 3 mL lidocaine 2%-bupivacaine 0.5%. One minute after the injection of 27 mL of the same mixture, a complete anaesthetic block occurred with hypotension and loss of consciousness requiring intubation and controlled ventilation during 3h30, without sequelae. Lumbar plexus block using a posterior approach must be performed cautiously and a slow and fractionated injection of the full dose is recommended.

Aged↗
PubMed1998

Immune thrombocytopenic purpura after recombinant hepatitis B vaccine: retrospective study of seven cases.

Recombinant hepatitis B vaccine is usually well tolerated. Clinical and laboratory test manifestations with immunologic mechanisms have nonetheless been described following use of this vaccine. We retrospectively report 7 cases of thrombocytopenia occurring within 3 months (7 weeks on the average) of 1 or following injections of recombinant hepatitis B vaccine. Four boys and 3 girls, average age 12 y, were involved. Three had a history of immune thrombocytopenic purpura. Four had haemorrhagic manifestations. The haemogram showed thrombocytopenia (24 x 10(9)/l on the average) without alterations of the other lines. Infectious and immune aetiologies were excluded in all cases. The course varied after treatment by corticosteroids, high-dose intravenous immunoglobulin, or both. After describing the different manifestations subsequent to recombinant hepatitis B vaccination, we discuss post-vaccinal thrombocytopenias (vaccines in question, mechanisms) and the reality of this entity.

Adolescent↗
PubMed1998

Meta-analysis of the efficacy of extradural clonidine to relieve postoperative pain: an impossible task.

Clonidine, an alpha2 adrenoceptor agonist, has anti-hypertensive and anti-nociceptive effects. It is commonly used in association with local anaesthetics and opioids to enhance the quality and duration of extradural analgesia in the postoperative period, and to decrease the incidence of side effects. As a sole analgesic, it has seldom been used to relieve postoperative pain. The dose of extradural clonidine to achieve good pain relief without deleterious side effects remains undetermined. In order to address this problem, we performed a computer search via two well-known databases, Medline and Excerpta Medica, covering the period from 1985 to September 1997. One hundred and fifty-nine articles were retrieved of which 38 dealt with extradural clonidine and postoperative pain. All but 16 studies suffered from serious design flaws, such as lack of controls and/or randomization, or inadequate statistical analysis. The data from these studies were difficult to interpret because of the tremendous variation in variables, especially dose of clonidine, level of extradural injection, time of administration, type of anaesthesia, type of surgery, and reference and rescue drugs. The simultaneous extradural use of local anaesthetics and opioids further hindered data interpretation, and precluded any meta-analysis. Proposals for a standard study design are made to help comparison between studies involving extradural clonidine and postoperative pain.

Adrenergic alpha-Agonists↗
PubMed1998

Sedation depends on the level of sensory block induced by spinal anaesthesia.

We have investigated the relationship between the extent of spinal block and occurrence of sedation. In a first series of 43 patients, the distribution of sedation score (measured on the Ramsey scale) was related to the extent of spinal block (pinprick). In a second series of 33 patients, the relationship between sedation score and spinal block persisted after injection of midazolam 1 mg. This study confirmed that high spinal block was associated with increased sedation.

Adolescent↗
PubMed1998

Clonidine does not impair redistribution hypothermia after the induction of anesthesia.

UNLABELLED: Clonidine is commonly given for premedication, and it impairs normal thermoregulatory responses to warm and cold stimuli while depressing sympathetic tone. We studied the effect of premedication by clonidine on redistribution hypothermia induced by the induction of anesthesia. Sixteen ASA physical status I or II patients were randomly assigned to receive either clonidine 150 micrograms or a placebo. Anesthesia was induced 45 min later by thiopental, fentanyl, and vecuronium i.v. and was maintained by the administration of 0.6% isoflurane. We monitored central core (tympanic) temperature and skin surface temperatures at the forearm and the fingertip during the 2 h after the induction of anesthesia before surgery. We estimated skin blood flow at the level of the forearm by using laser Doppler during the same period. The core temperature decreased comparably in the two groups of patients, from 37.1 +/- 0.2 degrees C to 35.3 +/- 0.4 degrees C and from 37.1 +/- 0.2 degrees C to 35.5 +/- 0.3 degrees C in the clonidine and placebo groups, respectively. The forearm-fingertip surface temperature gradient decreased similarly in the two groups. There was no evidence of cutaneous vasoconstriction. The laser Doppler index at the fingertip increased similarly in the two groups, as did the forearm-fingertip temperature gradient. We conclude that premedication with clonidine does not significantly impair the profile of central hypothermia induced by heat redistribution after the induction of anesthesia. IMPLICATIONS: The induction of general anesthesia is associated with redistribution hypothermia. This study shows that premedication with oral clonidine does not worsen the decrease in core temperature resulting from general anesthesia.

Adrenergic alpha-Agonists↗
PubMed1998

Infection after transurethral resection of the prostate: variation among centers and correlation with a long-lasting surgical procedure. Association pour la Recherche en Anesthésie-Réanimation.

OBJECTIVES: The purpose of this study was to analyze the risk factors of postoperative infection following transurethral resection of the prostate (TURP). METHODS: 857 consecutive patients scheduled for TURP were included in a French multicenter prospective study (12 surgical centers). For each patient, data were collected and analyzed as risk factors of postoperative infection. Statistical analysis used the chi 2 test or Student's test for univariate analysis, then stepwise logistic regression for multivariate analysis. RESULTS: The incidence of post-TURP infection was 21.6%: urinary tract infection (19.3%) and bacteremia and/or septic shock (2.3%). Multivariate analysis documented three independent risk factors of postoperative infection: preoperative bacteriuria (p < 0.003), duration of surgical procedure > 70 min (p < 0.01) and the surgical center (p < 0.00001). CONCLUSION: The duration of the surgical procedure is an important postoperative risk factor of infection and there is a major difference between centers in terms of postoperative risk of infection. Further studies are needed to explain this last phenomenon.

Aged↗
PubMed1998

Changes in cerebral blood flow during PaCO2 variations in patients with severe closed head injury: comparison between the Fick and transcranial Doppler methods.

OBJECT: The aim of this study was to reassess whether middle cerebral artery blood flow velocity (MCAv) variations measured by transcranial Doppler ultrasonography during acute PaCO2 manipulation adequately reflect cerebral blood flow (CBF) changes in patients with severe closed head injury. METHODS: The study was performed by comparing MCAv variations to changes in CBF as assessed by measurements of the difference in the arteriovenous content in oxygen (AVDO2). The authors initiated 35 CO2 challenges in 12 patients with severe closed head injury during the acute stage. By simultaneous recording of systemic and cerebral hemodynamic parameters, 105 AVDO2 measurements were obtained. Patients were stratified into two groups, "high" and "low," with respect to whether their resting values of MCAv were greater than 100 cm/second during moderate hyperventilation. Four patients displayed an elevated MCAv, which was related to vasospasm in three cases and to hyperemia in one case. The PaCO2 and intracranial pressure levels were not different between the two groups. The slope of the regression line between 1 divided by the change in (delta)AVDO2 and deltaMCAv was not different from identity in the low group (1/deltaAVDO2 = 1.08 x deltaMCAv - 0.07, r = 0.93, p < 0.001) and significantly differed (p < 0.05) from the slope of the high group (1/deltaAVDO2 = 1.46 x deltaMCAv - 0.4, r = 0.83, p < 0.001). CONCLUSIONS: In patients with severe closed head injury, MCAv variations adequately reflect CBF changes as assessed by AVDO2 measurements in the absence of a baseline increase in MCAv. These observations indicate that both moderate variations in PaCO2 and variations in cerebral perfusion pressure do not act noticeably on the diameter of the MCA. The divergence from the expected relationship in the high group seems to be due to the heterogeneity of CO2-induced changes in cerebrovascular resistance between differing arterial territories.

Adolescent↗
PubMed1998

[Scleroderma renal crisis. 7 cases and review of the literature].

We report a series of seven patients who had scleroderma renal crisis. Their primary clinical and laboratory features along with the details of their management were compared with those of similar cases from the literature. The seven patients died within one to four months of the diagnosis with a pattern of acute renal failure, left ventricular failure and malignant hypertension. Histopathologic examination was performed in four of the patients, in two of whom it revealed thickening of the wall of the interlobular arteries related to the scleroderma, and in the other two patients nonspecific lesions of malignant hypertension. This histopathologic particularity led us to propose, on the basis of multiple renal biopsies performed in patients with scleroderma, a lesion chronology of the kidney in patients with scleroderma. Nevertheless, the triggering factors and pathophysiologic mechanisms of scleroderma renal crisis remain unclear and its prognosis is severe. Early treatment with angiotensin-converting enzyme inhibitors and other vasodilatators administered intravenously can prevent death and dialysis.

Acute Kidney Injury↗
PubMed1998

Hemodynamic effects of epinephrine associated to an epidural clonidine-bupivacaïne mixture during combined lumbar epidural and general anesthesia.

Clonidine or epinephrine are frequently combined to epidural local anesthetics to strengthen sensory block and prolong analgesia. Both drugs impair the hemodynamic profile of central neural blockade but the effects of their combination on arterial pressure and heart rate are not known and were examined in this double-blind prospective randomised study. Forty four patients scheduled for lumbar disc surgery were allocated to two groups. Epidural anesthesia was obtained by administration of 150 micrograms clonidine in 15 ml bupivacaine 0.25% solution without (group C) or with (group C + E) 37.5 micrograms epinephrine. Systolic, mean, diastolic arterial pressure and heart rate were measured throughout the study. Combined epidural and general anesthesia induced a significant decrease in arterial pressure and heart rate in both groups. SAP and MAP decreased significantly less in the patients receiving epinephrine. Low dose epidural epinephrine decreases arterial pressure instability during combined epidural and general anesthesia.

Adolescent↗
PubMed1997

[Brain death and organ procurement: a specific context].

Brain death is defined as an irreversible damage to the brain stem associated with lesions of the hemispheres. It determines the irremediable destruction of the whole body which occurs within a short delay. Brain death diagnosis is identified from a series of neurological criteria, i.e.: the loss of consciousness, the disappearance of brainstem reflexes, the lack of spontaneous breathing movements. Legal considerations in use in France imply that brain death must be confirmed by two isoelectric encephalographs or by the absence of cerebral perfusion on cerebral arteriography. The diagnosis must be established by two practitioners who are not involved in transplantation activity. Prexisting cardiac activity and organ perfusion allow indeed organs and tissue procurement for transplantation. Organ procurement is supported by intensive care of the brain dead patient aiming to correct hemodynamic, ventilatory and metabolic disorders related to brain death. Organ donation implies that one would know the patient's will which would have been clearly expressed during his lifetime. Organ harvesting is organized according to guidelines for local practice and regional and national allocation. In consideration of transplantation requirements there is a persisting organ shortage for several years. Efforts must be directed toward an improvement in brain dead patients identification and management.

Brain Death↗
PubMed1997

Sleep apnea-like syndrome induced by nitrous oxide inhalation in normal men.

To study the relationship between sedation and respiration under N2O, we performed polysomnographic recordings in 15 healthy men with documented normal breathing patterns during sleep. In a first study in five subjects, we found that 50% N2O in O2 compared to 50% O2 increased sleep latency to stage 2 (59 +/- 12 vs. 17 +/- 3 min), total sleep duration (59 +/- 12 vs. 26 +/- 11 min), depth of sleep and respiratory events during sleep (18 +/- 5 vs. 1 +/- 1/h of sleep). In a second study, ten subjects were exposed to N2O (30 and 50%) in O2 during two consecutive experimental periods. Eight subjects had EEG features of physiological sleep, but nevertheless exhibited a total of 181 respiratory events. Respiratory disturbance index (RDI) during sleep was similar under 30 and 50% N2O (25 +/- 7 and 25 +/- 5/h of sleep, respectively). Obstructive events predominated, except in three subjects during N2O 30% and one during N2O 50% exposure. We conclude that N2O can induce central and obstructive sleep apneas.

Administration, Inhalation↗
PubMed1997

[Interviews with families of organ donors: analysis of motivation for acceptance or refusal of donation].

OBJECTIVE: The reasons for organ donation acceptance or refusal are still unclear. This study analysed the influence of the circumstances of the conversations with the relatives of brain dead patients on their consent for organ donation. STUDY DESIGN: Prospective study. MATERIAL: The analysis included 41 questionnaires collected over nine months in one organ harvesting centre and focusing on the circumstances of death, the conditions of the conversations and the reasons for acceptance or refusal. METHODS: Questionnaire filled in by the physicians after the interviews of the relatives of brain dead patients. RESULTS: The refusal rate was higher (54 vs 21%) when only one physician participated in the conversation, when more than two relatives had to decide (42 vs 24%), when conversations took place during night or when the request for organ donation followed immediately the announcement of death (43 vs 20%). Most often the relatives gave their decision within minutes following the request. CONCLUSION: The circumstances of conversation with families play an essential role in their decision-making. A written guideline implementation for these conversations would probably be beneficial for the decisions of families in favour of organ donation.

Adolescent↗
PubMed1997

Intra-articular morphine and clonidine produce comparable analgesia but the combination is not more effective.

Both intra-articular morphine and clonidine produce analgesia. This study was designed to compare the analgesic effects of the two drugs, used separately and in combination. We studied 90 patients undergoing arthroscopy of the knee under general anaesthesia. Patients were allocated randomly to receive 20 ml of intra-articular isotonic saline solution containing morphine 2 mg, clonidine 150 micrograms or both. Pain was assessed on an visual analogue scale after operation and time for rescue medication was measured. There was no difference in VAS scores between the three groups and the time for rescue analgesic was comparable. We conclude that intra-articular morphine and clonidine have comparable analgesic effects in the doses used. The combination of both drugs did not seem to increase analgesia.

Adolescent↗
PubMed1997

Changes in cerebral hemodynamics after a single dose of clonidine in severely head-injured patients.

alpha 2-Adrenergic agonists induce cerebral vasoconstriction, reduce intracranial pressure (ICP) in experimental animals and may be useful in the hemodynamic management of head-injured patients. We studied the effects of the alpha 2 agonist clonidine on the cerebral circulation in 12 head-injured patients (Glasgow Coma Scale score < 8). Middle cerebral artery flow velocity (MCAV), ICP, mean arterial pressure (MAP), and cerebral perfusion pressure (CPP), were continuously recorded before (T0), at the end (T1), and 30 min after (T2) a 10-min intravenous (i.v.) infusion of 2.5 micrograms/kg clonidine. The cerebral arteriovenous oxygen content difference (AVDO2) and Paco2 were sequentially obtained. ICP, Paco2, AVDO2, and MCAV did not change after clonidine administration. In contrast, MAP and CPP decreased (P < 0.05 and P < 0.05, respectively, at T1 and T2). Three subjects displayed a transient increase in ICP (> 10 mm Hg) at T1; this increase was concomitant with the decrease in MAP. Clonidine administered as an i.v. infusion may induce a critical but transient increase in ICP in some severely head-injured patients. This effect may result from cerebral autoregulatory vasodilation and increased cerebral blood volume as a response to the hypotensive effects of clonidine.

Adrenergic alpha-Agonists↗