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Biomedical subjects

G Boulard

Publications and source records attributed to G Boulard.

At least 37 records · Page 2Linked to original sources
PubMed2003

[The impact of a French guideline on the clinical management of severe head injury (SHI) published in 1999].

OBJECTIVE: To evaluate the impact of a French guideline on the clinical management of severe head injury (SHI) published in 1999. STUDY DESIGN: Nationwide survey. METHODS: 182 medical centres answered the inquiry. RESULTS: 111 centres declared to manage such patients suffering from SHI. 68% of doctors from these clinical departments did report to have read these guidelines. Fifty percent of them found in these guidelines useful data for their clinical practice. Forty four percent of centres could not monitor ICP lacking neurosurgical facility in their hospital. Conversely, all hospitals with neurosurgery available did monitor ICP. Seventy six percent of centres reported difficulties to find a facility, which would take these patients in charge when discharged from ICU. We analysed the main items included in the guidelines and report their impact. Seventy four percent of responders found that clinical management of SHI patients had improved during the last years. CONCLUSION: The French guidelines had a significant impact and seem to have provided a useful aid to clinical management of SHI patients. ICP monitoring and the shortage in post-ICU facilities are remaining issues.

Craniocerebral Trauma↗
PubMed2003

[Osmotic cerebral oedema: the role of plasma osmolarity and blood brain barrier].

There are five types of oedema: vasogenic, cytotoxic, interstitial, hyperemic and osmotic. The differences lie on the type and localization of the oedema, the state of the blood-brain barrier (BBB) and the pathological context. Under physiological conditions, the osmolarity of extra cellular fluids (ECFs) is equal on both sides of the BBB. However, the pathophysiological variations of circulating osmolarity (including acute hyponatremia and hypernatremia) do not affect, at the same time, the osmolarity of cerebral ECFs. This situation generates an osmotic gradient on either side of the BBB. The latter, if intact, behaves like a semi-permeable membrane allowing water transport according to the osmotic laws. Depending on its direction, water movement could induce cerebral liquid inflation (i.e. osmotic oedema) or cerebral dehydration. In case of osmotic insult, cerebral cell modify their active osmotic molecular contents in order to limit volume variation. There are two types of osmoactive molecules, organic (i.e. ideogenic osmoles: amino acids, polyols and trimethylamines) and non organic (i.e. electrolytes). In the event of plasma hypotonicity, cerebral cells expel active osmotic molecules to reduce the osmotic gradient and water movement thereby reducing edema. The opposite reaction is observed in the case of hypertonic insult. This cerebral osmoregulation becomes more effective, the slower the osmotic disorder. It explains, for example, why patients with chronic and severe hyponatremia could be asymptomatic. Severe osmotic oedema is observed mainly in water intoxication, acute hyponatremia or too rapid reduction of hyperosmolarity. However, osmotic oedema is not limited to extreme clinical circumstances. Hyponatremia, even modest, could modify cerebral blood volume and impair osmoregulation. Generally these minor modifications do not affect normal brain tissue. In the presence of cerebral lesion, osmoregulation operates only in areas of preserved BBB. The pathological zones are therefore exposed to osmotic oedema (even in cases of moderate hyponatremia) with deterioration of both clinical status and intracranial pressure. This authentic phenomenon could be insidious and difficult to differentiate from osmotic central oedema. Hyponatremia constitutes an authentic secondary cerebral insult of systemic origin, an entity clearly identified by experimental studies to justify the choice between crystalloids and colloids in neuroanaesthesia and neurointensive care. These studies have revealed an increase in water content in normal brain tissues after administration of hypotonic solutions. The increase in plasma osmolarity as a treatment modality using mannitol or hypertonic saline is based on the same concepts. The most remote indication is the occurrence of a reactive mydriasis in the context of trauma for example. More recently, therapeutic hypernatremia has been proposed to control intracranial hypertension.

Blood-Brain Barrier↗
PubMed2003

[Spectral analysis of the ECG R-R interval permits early detection of vagal responses to neurosurgical stimuli].

OBJECTIVE: To assess the efficacy of ECG spectral analysis, compared with heart rate (HR) monitoring in the detection of vagal response to surgical stimuli. METHODS: Twenty Asa II-III patients (age: 65 +/- 13 years) scheduled for surgery of cerebellopontine angle or implantation of sacral root stimulator were examined. Target controlled infusion of propofol (2-4 microg x ml(-1)) and remifentanil (4 ng x ml(-1)) was guided by the bispectral index (Bis). Arterial pressure via a radial catheter, pulse oximetry and end tidal CO2 were continuously monitored. Spectral analysis was achieved by connecting a computer to the cardiorespiratory monitor. Online power spectrum densities were calculated from the ECG R-R interval by software based on the fast Fourier transform (LabView, National Instruments, USA). Low frequency (LF: 0.04-0.15Hz) and high frequency (HF: 0.15-0.4Hz) were associated with sympathetic and parasympathetic activities respectively. We defined vagal reaction as a decrease in FC or an increase in HF >10% of the prestimuli value. HF and FC were compared according to the detection delay (by a Student t test with p < 0.05 considered significant) and a concordance test with a kappa coefficient (kappa): -1 = total discordance to 1 = total concordance. RESULTS: Twelve vagal reactions (observed in 8 patients) were detected within 5.5 +/- 1.3 s (HF) and 12.4 +/- 1.6 (FC); p < 0.001. Concordance between the 2 parameters was 95% (kappa =0.9). CONCLUSION: The ECG spectral analysis is a non-invasive technique, which permits the detection of intra-operative vagal reactions earlier than conventional monitoring of HR.

Aged↗
PubMed2002

[Cerebrospinal fluid shunting: anesthetic particularities].

The symptomatic treatment of hydrocephalus remains cerebrospinal fluid (CSF) drainage to an external reservoir (external CSF drainage) or to an internal cavity mainly the peritoneum or the right atrium via a unidirectional valve (internal CSF drainage) and finally by endoscopic ventriculocisternostomy. Local anaesthesia is adequate for external CSF drainage in adults and children above 10 years while general anaesthesia is required in all other cases. The main problems encountered in these patients are difficult intubation and full stomach associated with increased intracranial pressure. The anaesthetic approach should favour homeostasis. With the exception of ketamine and enflurane, the majority of anaesthetic drugs can be used. Anti-epileptic drug are mandatory. Antibioprophylaxis mainly against staphylococcus is systematic in internal CSF drainage. Rapid emergence from anaesthesia and extubation should be encouraged. Complications (infectious, mechanical and bleeding kinds) are frequent and are often the cause of reinterventions or revisions of the device, exposing the patients to iterative anaesthesia. Furthermore, patients with shunts are at risk of malfunction of the device when exposed to situations like pregnancy, magnetic resonance imaging, or laparoscopy. Under these circumstances, it is recommended to associate the neurosurgical team in the management of these patients and to verify that the shunt is working well before and after the procedure or event.

Anesthesia↗
PubMed2002

[Anesthesiologists in France. First results of the national survey conducted in 1999 by the French College of Anesthesiologist, The French National Society of Anesthesia and Intensive Care with the scientific support of the National Institute for Demographic Studies].

OBJECTIVES: Fears related to the future of anaesthesia manpower in France have led the French College of Anaesthesiologists (Cfar) and the French Society of Anaesthesia and Intensive Care (Sfar), in scientific partnership with the National Institute for Demographic Studies (Ined), to set-up a national survey among French anaesthetists (MAR) practicing in France, to describe their demographic evolution and to analyse their professional activities. METHODS: The survey was based on a personal questionnaire, filled by each individual, approved by the National Commission on Informatics and Freedoms (CNIL). The survey was conducted in November 1998, in the 1484 hospitals, public (590) and private (894) where anaesthetics are performed, under the control of local and regional referents. RESULTS: The anaesthesiologists positions count gave a total of 9741 positions shared between 5694 in public practice (58%), 3569 in private practice (37%) and 478 in private hospitals taking part to the national health service-PSPH (5%). The evaluation of the number of anaesthesiologists from the number of positions has made necessary a methodology of rectification of the survey to take in account the lack of response and the multiple sites of activity. The survey allows an evaluation of around 8876 physicians practising anaesthesia and intensive care in France at the beginning of 1999, among them 216 overseas. This census is in concordance with the count made by the Medical Council--Ordre des médecins--which published a number of 8716 anaesthesiologists in France, and 234 overseas, at the 1st January 1999, corresponding to a total of 8950. The annual demographic growth has felt from 9% per year, before 1989, to reach the level zero, in 1999. The masculinisation of the speciality is growing with a proportion of 35.7% of females, as well as ageing, the overage of age increasing from 42.8 in 1989 to 45.9 years in 1999. The pyramid of ages does not correspond to a growing population but to ageing people due to a decrease of the youngest classes. The medical density of 14.75 anaesthesiologists for 100,000 inhabitants in 1999, compared to 12.9 in 1989, is slightly above the European average, but the geographic distribution is very unequal between north and south, the large cities, centre of a university hospital, and the smaller one even if a reduction of differences is observed. The study and the analysis of professional activities bring important data to take in account side of demographic evolution. CONCLUSION: The demographic evolution must integrate non-only the reduction of the entries in the speciality, of the retirements, but also the sociological evolutions linked to the working time reduction. The solutions face to the promised shortcut of manpower consist of a reorganisation of the structures, a new definition of tasks and managements, without the possibility to avoid and adjustment of the anaesthesiologists population.

Adult↗
PubMed2002

Multivariate analysis of determinants of bacterial contamination of whole-blood donations.

BACKGROUND AND OBJECTIVES: Introduction of bacteria into blood components at the collection stage seems to be a frequent occurrence. We therefore assessed determinants of bacterial contamination of whole-blood donations to gain insight into contamination mechanisms and direct prevention. MATERIALS AND METHODS: A cross-sectional study was carried out on donors accepted for whole-blood donation in four French blood banks. Each blood bank used its own two-stage procedure for phlebotomy site preparation. Contamination was identified by culturing two 15-ml samples (collected aseptically at the outset of donation) in a BacT/Alert 240 system. Determinants were assessed by logistic regression analysis. RESULTS: Bacterial contamination, mainly by skin flora, occurred in 76 (2.2%) out of 3385 donations. Significant determinants were as follows: the blood bank (odds ratio [OR] range = 3.0-5.6, P < 0.001); lack of repetition of scrub (OR = 2.7, P = 0.032); and donor age > 35 years (OR = 1.8, P = 0.036). CONCLUSION: Systematic scrub repetition should be implemented to reduce bacterial contamination by skin flora at the collection stage. Further research is required to clarify the role of different antiseptic agents and of donor age.

Adult↗
PubMed2001

[Plasma osmolarity and cerebral volume].

Under normal physiological conditions, the osmolarity of extracellular fluids (ECFs) and natremia are controlled by two regulatory mechanisms modulating the water balance and sodium outflow from information collected by the osmoreceptors and baroreceptors, respectively. As well, under normal physiological conditions, water and electrolytes of brain ECFs are secreted by the endothelial cells of brain capillaries. Furthermore, isotonicity is present on both sides of the blood-brain barrier. In the event of systemic osmolarity disorders, water transport subject to osmosis laws occurs at the level of the blood-brain barrier. In the case of plasmatic hyperosmolarity cerebral dehydration is observed, while cerebral edema occurs in the contrary case. However, plasmatic osmolarity disorders have less effect on the cerebral volume when their introduction is slow. Experimentation in acute conditions shows that measured variations of the cerebral water content are lower than calculated variations, thus suggesting the existence of an adaptive mechanism, that is, the cerebral osmoregulation which limits the variation of the volume of brain cells by modulating their osmoactive molecule content. These osmoactive molecules are, on the one hand, the electrolytes, which are early and rapidly mobilized, and, on the other hand, the organic osmoles (amino acids, etc.), whose secretion is slower and delayed. This phenomenon should be taken into account in the treatment of osmolarity disorders. Thus, the related-risk of treatment for natremia disorders is therapeutic reversal of the osmotic gradient at the level of the blood-brain barrier. This reversal, which corresponds to a second osmotic stress, requires the implementation of a new procedure of cerebral osmoregulation in the opposite direction of the preceding one. As successive osmotic stresses decrease the effectiveness of brain osmoregulation, the risk for cerebral dehydration and pontine myelinolysis increases when the treatment of chronic hyponatremia is too aggressive. Finally, the choices for infusion solutions in neurosurgery and treatment for osmolarity disorders are also based on the relationships that exist between plasmatic osmolarity and the brain.

Animals↗
PubMed2001

Efficacy of a new collection procedure for preventing bacterial contamination of whole-blood donations.

BACKGROUND: Transfusion-related bacterial contamination is a serious problem. The introduction of bacteria into donations at the collection stage seems frequent, despite well-conducted phlebotomy site preparation. Additional preventive measures are required. STUDY DESIGN AND METHODS: The aim of this study was to assess the potential efficacy of excluding the first 15 mL of blood to reduce the bacterial contamination of donations. A special device allowed the aseptic collection of two samples at the beginning of donation: S1 (first 15 mL) and S2 (next 15 mL). Bacteriologic cultures of S1 and S2 were performed by using an automated system. The procedure's efficacy was measured by the proportion of positive donations in S1 that were then negative in S2. RESULTS: S1 and/or S2 were positive in 76 (2.2%) of 3385 donations. In about three-fourths of the culture-positive donations, contamination was detected in the first 15-mL sample only. Gram-positive cocci accounted for 81 percent of species, gram-positive bacilli for 14 percent, and gram-negative bacilli for 5 percent. The new procedure would have prevented the introduction of bacteria in 55 donations, reducing to 0.6 percent the risk of contamination from the first 15 mL collected. CONCLUSION: Although the final effect on blood component bacterial contamination rates cannot be derived from the study, excluding the first 15 mL of blood may reduce the rate of bacterial contamination in donations.

Adult↗
PubMed2000

Prospective survey of colonization and infection caused by SHV-4 producing Klebsiella pneumoniae in a neurosurgical intensive care unit.

The occurrence of extended-spectrum beta-lactamase producing enterobacteria (ESBLE) has been prospectively surveyed in a neurosurgical intensive care unit (ICU). Of the 47 patients examined, 8 were identified as faecal carriers, and 2 of them developed a subsequent urinary tract infection. ESBLE were also detected in the immediate environment of five colonized and/or infected patients. All isolates were Klebsiella pneumoniae of a particular biotype which exhibited a similar antibiotype and produced an SHV-4 type beta-lactamase. However, plasmid profiling and ribotyping revealed that strains isolated from seven patients of hall A were a single epidemic clone, whereas strains isolated from the eighth patient of hall B were different. Comparison between the characteristics of patients who carried an ESBLE during the surveillance period, and control patients who did not, showed that a recent surgery, and the length of ICU stay were significantly associated with the acquisition of ESBLE.

Cross Infection↗