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Biomedical subjects

H Gervais

Publications and source records attributed to H Gervais.

At least 19 recordsLinked to original sources
PubMed2004

Initial chemotherapy in gliomatosis cerebri.

BACKGROUND: Because of the diffuse nature of gliomatosis cerebri (GC), surgery is not suitable, and large field radiotherapy carries the risk of severe toxicity. In this setting, initial chemotherapy warrants further investigation. METHODS: The authors treated 63 consecutive patients with GC with initial chemotherapy consisting of either PCV (procarbazine, 60 mg/m2 on days 8 to 21; CCNU, 110 mg/m2 on day 1; and vincristine, 1.4 mg/m2 on days 8 and 29) or temozolomide (TMZ; 150 to 200 mg/m2 for 5 days every 4 weeks). There were 40 men and 23 women, with a median age of 48 years (range, 17 to 74 years) and a median Karnofsky performance status of 90 (range, 50 to 100). GC was initially present at diagnosis in 49 patients (primary GC), whereas 14 patients with a circumscribed glioma at onset developed secondary GC after a median follow-up period of 5.11 years. GC was classified based on the predominant tumor cells as astrocytic, oligodendroglial, or mixed GC. RESULTS: Seventeen patients received 1 to 6 cycles (median, 5) of PCV, and 46 received 2 to 24 courses (median, 13) of TMZ. Grade 3 to 4 hematologic toxicity was seen in 4 of 17 (23.5%) patients treated with PCV and in 4 of 46 (8.6%) of those treated with TMZ. Clinical objective responses were observed in 21 of 63 (33%) patients, and radiologic responses were seen in 16 of 62 (26%), with no significant difference between the two regimens. For all patients combined, the median progression-free survival (PFS) and overall survival (OS) were 16 months and 29 months, respectively. Regardless of the chemotherapeutic regimen, oligodendroglial GC had a better prognosis than astrocytic and oligoastrocytic GC in terms of PFS (p < 0.02) and OS (p < 0.0001). CONCLUSION: Initial chemotherapy is useful for some patients with gliomatosis cerebri. Temozolomide is well tolerated and appears to be a valuable alternative to procarbazine-CCNU-vincristine, especially for those with slow-growing, low-grade GC.

Adolescent↗
PubMed2004

Superior temporal sulcus anatomical abnormalities in childhood autism: a voxel-based morphometry MRI study.

The underlying neurobiology of autism, a severe pervasive developmental disorder, remains unknown. Few neocortical brain MRI abnormalities have been reported. Using rest functional brain imaging, two independent studies have described localized bilateral temporal hypoperfusion in children with primary autism. In order to search for convergent evidence of anatomical abnormalities in autistic children, we performed an anatomical MRI study using optimized whole-brain voxel-based morphometry (VBM). High-resolution 3-D T1-weighted MRI data sets were acquired in 21 children with primary autism (mean age 9.3 +/- 2.2 years) and 12 healthy control children (mean age 10.8 +/- 2.7 years). By comparing autistic children to normal children, we found bilaterally significant decreases of grey matter concentration located in superior temporal sulcus (STS) (P < 0.05 corrected, after small volume correction; SVC). Children with autism were also found to have a decrease of white matter concentration located in the right temporal pole and in cerebellum (P < 0.05, corrected) compared to normal children. These results suggest that autism is associated with bilateral anatomical abnormalities localized in the STS and are remarkably consistent with functional hypoperfusion previously reported in children with autism. The multimodal STS areas are involved in highest level of cortical integration of both sensory and limbic information. Moreover, the STS is now recognized as a key cortical area of the "social brain" and is implicated in social perceptual skills that are characteristically impaired in autism. Therefore, the convergent anatomical and functional temporal abnormalities observed in autism may be important in the understanding of brain behavior relationships in this severe developmental disorder.

Adolescent↗
PubMed2001

[Hemichorea, hemiballism disclosing non-ketotic hyperglycemia].

Non ketotic hyperglycemia is a metabolic disorder which can induce various hyperkinetic disorders. We report the case of a 74-year old woman admitted to hospital because of choreo-ballic movements of her left hemibody. Laboratory tests revealed non-ketotic hyperglycemia. CT scan showed an increased density in the right putamen and head of caudate. Magnetic resonance imaging disclosed a hyperintense signal involving the right putamen on T1-weighted images. On T2-weighted images, there was a slight hyperintensity in the right putamen and head of caudate. Correction of the underlying hyperglycemia led to complete resolution of abnormal movements. Pathophysiology of this clinicoradiologic syndrome is briefly discussed.

Aged↗
PubMed2000

Improved outcome prediction in unconscious cardiac arrest survivors with sensory evoked potentials compared with clinical assessment.

OBJECTIVE: To compare the prognostic ability of sensory evoked potentials in cardiac arrest survivors with the outcome predicted by a panel of experienced emergency physicians based on detailed prehospital, clinical, and laboratory data. DESIGN: Inception cohort study. SETTING: Medical intensive care unit and department of emergency medicine at a university hospital. PATIENTS: A total of 162 unconscious, mechanically ventilated patients who survived > or =24 hrs after resuscitation from cardiac arrest. INTERVENTIONS: Recording of sensory evoked potentials and outcome prediction after review of detailed clinical and laboratory data by emergency physicians within 24 hrs after cardiac arrest. MEASUREMENTS AND MAIN RESULTS: At 6 months, the outcome of 36 patients was classified as favorable and 126 patients were rated as poor. After review of prehospital data, emergency physicians predicted favorable vs. poor outcome with a sensitivity of 70% and a specificity of 65%. After additional assessment of data 1 hr after cardiac arrest, the sensitivity of emergency physician predictions increased to 80%, whereas the specificity decreased to 48%. Outcome prediction by emergency physicians was most accurate after obtaining detailed patient data 24 hrs after cardiac arrest (sensitivity, 81%; specificity, 58%). In 35 of 36 patients with favorable outcomes, the cortical evoked potential N70 peak was detected between 72 and 128 msec. Of 113 patients with an N70 peak latency >130 msec or an absent N70 peak, all except one had a poor outcome. By using a cutoff of 130 msec, the N70 peak latency alone had a sensitivity of 94% and a specificity of 97%. The predictive accuracy of the N70 peak latency was significantly higher than the clinical assessment 24 hrs after cardiac arrest (91% vs. 76%, p = .0003). CONCLUSION: In unconscious cardiac arrest survivors, a recording of long-latency sensory evoked potentials is more accurate in predicting individual outcome than an emergency physician review of clinical data.

Analysis of Variance↗
PubMed1999

Pharmacokinetics and pharmacodynamics of hydroxyethyl starch in hypovolemic pigs; a comparison of peripheral and intraosseous infusion.

Intraosseous (i.o.) infusion is considered a useful technique for the administration of medications and fluids in emergency situations when peripheral intravascular access is not possible. This study investigated the effectiveness of i.o. versus intravenous (i.v.) infusion of hydroxyethyl starch (HES 200/0.5) in hypovolemic pigs. Twenty-three pigs (8- to 9-week-old) were anaesthesized, instrumented and blood was withdrawn (25-30 ml/kg) to < 50 mmHg mean arterial pressure (MAP). The animals were left untreated in haemorrhage for 30 min. Relevant haemodynamic parameters were monitored and blood samples were collected for blood gas and HES concentration analysis. Infusion of HES via i.v. or i.o. line (20 ml/kg per h) carried out over a period of 30 min for volume resuscitation and measurements were taken every 5 min. Infusion was discontinued after 30 min and the animals were monitored for 1 h. Analysis of HES-pharmacokinetics and pharmacodynamics revealed no significant differences between i.o. and the i.v. administration. The results demonstrate i.o. infusion of HES to be a rapid and effective method for fluid resuscitation in hypovolemic shock.

Animals↗
PubMed1996

Cerebral resuscitation from cardiac arrest: treatment potentials.

In 1961, in Pittsburgh, PA, "cerebral" was added to the cardiopulmonary resuscitation system (CPR --> CPCR). Cerebral recovery is dependent on arrest and cardiopulmonary resuscitation times, and numerous factors related to basic, advanced, and prolonged life support. Postischemic-anoxic encephalopathy (the cerebral postresuscitation disease or syndrome) is complex and multifactorial. The prevention or mitigation of this syndrome requires that there be development and trials of special, multifaceted, combination treatments. The selection of therapies to mitigate the postresuscitation syndrome should continue to be based on mechanistic rationale. Therapy based on a single mechanism, however, is unlikely to be maximally effective. For logistic reasons, the limit for neurologic recovery after 5 mins of arrest must be extended to achieve functionally and histologically normal human brains after 10 to 20 mins of circulatory arrest. This goal has been approached, but not quite reached. Treatment effects on process variables give clues, but long-term outcome evaluation is needed for documentation of efficacy and to improve clinical results. Goals have crystallized for clinically relevant cardiac arrest-intensive care outcome models in large animals. These studies are expensive, but essential, because positive treatment effects cannot always be confirmed in the rat forebrain ischemia model. Except for a still-elusive breakthrough effect, randomized clinical trials of CPCR are limited in their ability to statistically document the effectiveness of treatments found to be beneficial in controlled outcome models in large animals. Clinical studies of feasibility, side effects, and acceptability are essential. Hypertensive reperfusion overcomes multifocal no-reflow and improves outcome. Physical combination treatments, such as mild resuscitative (early postarrest) hypothermia (34 degrees C) plus cerebral blood flow promotion (e.g., with hypertension, hemodilution, and normocapnia), each having multiple beneficial effects, achieved complete functional and near-complete histologic recovery of the dog brain after 11 mins of normothermic, ventricular fibrillation cardiac arrest. Calcium entry blockers appear promising as a treatment for postischemic-anoxic encephalopathy. However, the majority of single or multiple drug treatments explored so far have failed to improve neurologic outcome. Assembling and evaluating combination treatments in further animal studies and determining clinical feasibility inside and outside hospitals are challenges for the near future. Treatments without permanent beneficial effects may at least extend the therapeutic window. All of these investigations will require coordinated efforts by multiple research groups, pursuing systematic, multilevel research--from cell cultures to rats, to large animals, and to clinical trials. There are still many gaps in our knowledge about optimizing extracerebral life support for cerebral outcome.

Animals↗
PubMed1994

Thiopentone, thiopentone/ketamine, and ketamine for induction of anaesthesia in caesarean section.

Seventy-five healthy patients were randomly allocated to receive thiopentone, thiopentone/ketamine or ketamine for induction of anaesthesia for elective Caesarean section. Thiopentone resulted in the most pronounced and ketamine in the smallest drop in blood pressure, while the combination induced only moderate haemodynamic changes. Intra-operative awareness occurred in one patient in the thiopentone group, six of the ketamine patients had nightmares, and one patient of the combination group reported pleasant dreams but no awareness. The muscle tone of neonates in the thiopentone group was more reduced than in neonates in the other two groups. Infants delivered after uterine incision-to-delivery intervals exceeding 3 min more often had Apgar scores < 7 than those delivered in less than 3 min.

Adult↗
PubMed1991

Epinephrine dosage effects on cerebral and myocardial blood flow in an infant swine model of cardiopulmonary resuscitation.

Although epinephrine increases cerebral blood flow (CBF) and left ventricular blood flow (LVBF) during cardiopulmonary resuscitation (CPR), the effects of high dosages on LVBF and CBF and cerebral O2 uptake have not been examined during prolonged CPR. We determined whether log increment dosages of epinephrine would enhance LVBF and CBF and cerebral O2 uptake in an infant swine CPR model. We compared these responses with epinephrine to those with the alpha-adrenergic agonist, phenylephrine. CPR was performed in five groups (n = 6) of pentobarbital-anesthetized piglets (3.5-5.6 kg) receiving a continuous epinephrine infusion (0, 1, 10, and 100 micrograms.kg-1.min-1) or phenylephrine infusion (40 micrograms.kg-1.min-1). Plasma epinephrine concentrations increased 10-100-fold in the control group during CPR and in a stepwise manner such that concentrations were increased by more than 10(4) in the 100 micrograms.kg-1.min-1 epinephrine group. In the control group with no epinephrine infusion, LVBF decreased to less than 10 ml.min-1.100 g-1 by 5 min of CPR. With epinephrine in dosages of 10 and 100 micrograms.kg-1.min-1, LVBF at 5 min was 75 +/- 19 and 44 +/- 15 ml.min-1.100 g-1, respectively, which was significantly greater than values in the control group. With more prolonged CPR, LVBF remained significantly greater than that in the control group but only at 10 micrograms.kg-1.min-1 of epinephrine. Phenylephrine also increased LVBF for 10 min of CPR when compared with the control group. All dosages of epinephrine and phenylephrine maintained CBF close to prearrest values for 20 min of CPR. With prolonged CPR, 10 and 100 micrograms.kg-1.min-1 epinephrine resulted in significantly greater CBF than that in the control group. Incremental dosages of epinephrine did not statistically increase cerebral O2 uptake or lower the cerebral fractional O2 extraction when compared with the control group, despite the higher CBF that was generated. In this immature animal CPR model, 10 micrograms.kg-1.min-1 epinephrine is an optimal dosage for maximizing both CBF and LVBF, a dosage that substantially exceeds the current recommended epinephrine dosage for human infant CPR. In addition, for short periods of CPR, 40 micrograms.kg-1.min-1 phenylephrine increases CBF and LVBF to levels similar to those generated by high dosages of epinephrine.

Animals↗
PubMed1991

Improved blood flow during prolonged cardiopulmonary resuscitation with 30% duty cycle in infant pigs.

BACKGROUND: Sustained compression is recommended to maximize myocardial and cerebral blood flow during cardiopulmonary resuscitation (CPR) in adults and children. We compared myocardial and cerebral perfusion during CPR in three groups of 2-week-old anesthetized swine using compression rates and duty cycles (duration of compression/total cycle time) of 100 per minute, 60%; 100 per minute, 30%; and 150 per minute, 30%. METHODS AND RESULTS: Ventricular fibrillation was induced and CPR was begun immediately with a sternal pneumatic compressor. Epinephrine was continuously infused during CPR. Microsphere-determined blood flow and arterial and sagittal sinus blood gas measurements were made before cardiac arrest was induced and after 5, 10, 20, 35, and 50 minutes of CPR. At 5 minutes of CPR, ventricular and cerebral blood flows were greater than 25 ml.min-1 x 100 g-1 and were not significantly different between groups. When CPR was prolonged, however, myocardial and cerebral blood flows were significantly higher with the 30% duty cycle than with the 60% duty cycle. By 35 minutes, all myocardial regions had less than 5 ml.min-1 x 100 g-1 flow with the 60% duty cycle. In contrast, CPR with the 30% duty cycle at either compression rate provided more than 25 ml.min-1 x 100 g-1 to all ventricular regions for 50 minutes. By 20 minutes, most brain regions received 50% less flow with the 60% duty cycle compared with animals undergoing CPR with the 30% duty cycle (p less than 0.05). Cerebral oxygen uptake was better preserved with the 30% duty cycle. Chest deformation from loss of recoil was greater with the 60% duty cycle compared with the 30% duty cycle. CONCLUSIONS: We conclude that the shorter duty cycle provides markedly superior myocardial and cerebral perfusion during 50 minutes of CPR in this infant swine model. These data do not support recommendations for prolonged compression at rates of 100 per minute during CPR in infants and children.

Animals↗
PubMed1990

[Characteristics of cardiopulmonary resuscitation in pregnant women].

Cardiopulmonary resuscitation (CPR) during pregnancy is a rare event, but due to the increasing number of pregnant women with significant medical disorders it will gain more importance in the near future. Effective CPR with respect to survival of mother and infant can only be accomplished under optimal conditions. We discuss important pathophysiological alterations during pregnancy and, including recommendations in the available literature, we present a standardized protocol for life support for mother and infant. The protocol depends on the progress of the pregnancy. Compared to non-pregnant patients, pregnant women must be placed in a left lateral position immediately. If possible, the decision to perform open-chest CPR has to be made within 15 min of unsuccessful closed-chest CPR. In addition, during late pregnancy there should be no delay in performing an emergency cesarean section, even during CPR.

Female↗
PubMed1989

Organ blood flow and somatosensory-evoked potentials during and after cardiopulmonary resuscitation with epinephrine or phenylephrine.

Pure alpha-adrenergic agonists, such as phenylephrine, and mixed alpha- and beta-adrenergic agonists, such as epinephrine, raise perfusion pressure for heart and brain during cardiopulmonary resuscitation (CPR). However, with the high doses used during CPR, these drugs may directly affect vascular smooth muscle and metabolism in brain and heart. We determined whether at equivalent perfusion pressure, continuous infusion of phenylephrine (20 micrograms/kg/min) or epinephrine (4 micrograms/kg/min) leads to equal organ blood flow, cerebral O2 uptake, and cerebral electrophysiologic function. During 20 minutes of CPR initiated immediately upon ventricular fibrillation in anesthetized dogs, left ventricular blood flow was similar with epinephrine (45 +/- 9 ml/min/100 g) or phenylephrine (47 +/- 8 ml/min/100 g) infusion. The ratio of subendocardial to subepicardial blood flow fell equivalently during CPR with either epinephrine (1.23 +/- 0.06 to 0.70 +/- 0.05) or phenylephrine (1.32 +/- 0.07 to 0.77 +/- 0.05) administration. At similar levels of cerebral perfusion pressure (44 +/- 3 mm Hg), similar levels of cerebral blood flow were measured in both groups (27 +/- 3 ml/min/100 g). Cerebral O2 uptake was maintained at prearrest levels in both groups. Somatosensory-evoked potential amplitude was modestly reduced during CPR, but it promptly recovered after defibrillation. During CPR and at 2 hours after resuscitation, there were no differences between drug groups in the level of regional cerebral or coronary blood flow, cerebral O2 uptake, or evoked potentials. Therefore, with minimal delay in the onset of CPR and with equipotent pressor doses of phenylephrine and epinephrine, we found no evidence that one agent provides superior coronary or cerebral blood flow or that epinephrine by virtue of its beta-adrenergic properties adversely stimulates cerebral metabolism at a critical time that would impair brain electrophysiologic function. Moreover, epinephrine did not preferentially impair subendocardial blood flow as might be expected if it enhanced the strength of fibrillatory contractions.

Animals↗
PubMed1988

[Value of preoperative screening studies].

In order to develop a sensitive and economically reasonable preoperative screening program capable of identifying perioperative risk factors, we performed a prospective study on patients scheduled for elective urological surgery. According to age, 379 patients were assigned to six groups. After the history and physical examination had been completed the attending anesthesiologist classified the patient's anesthetic risk according to ASA criteria. Furthermore, based on his clinical impression he ordered an individual set of screening parameters (laboratory tests, X-ray films, electrocardiography (ECG), and other appropriate diagnostic procedures) to be done. This "individual" screening and its results were compared with the results of the larger "routine" preoperative screening program performed independently of the study for all patients. All cases were then followed up in order to document perioperative complications. We were thus, able to recognize risk-identifying screening parameters resp. pathological findings missed by the "individual" screening. Laboratory tests from the nonselective "routine" screening yielded pathological results in a relatively high percentage of 31.4% of cases. ECG alterations or chest X-ray findings relevant to the patient's anesthetic management were present in 26.1% resp. 13.6%. Observations missed by the "individual" screening, though important for the prevention of perioperative complications, were pathological ECGs in only 1.9% of all cases. An influence of patient age on the frequency of pathological screening results and perioperative complications could be shown. Laboratory tests, chest X-rays and additional diagnostic procedures should be restricted to patients with pathological results or physiological examination. Our results underline once more the importance of a carefully taken history, a meticulous physical examination and the preoperative performance of an ECG for patients of every age scheduled for anesthesia and surgery.

Adolescent↗
PubMed1988

[Models and methods in animal experiments in resuscitation].

Various animals models and several different methods are used in cardiopulmonary resuscitation (CPR) research. The animals used most frequently are dogs and pigs, but in each species thorax configurations, which might be an important factor in the mechanism of blood flow during CPR, are at great variance. The influence of anesthetics on cardiopulmonary and cerebral functions during and following resuscitation are largely unknown, and accordingly there is great variance in the techniques employed by individual researchers. The experimental design chosen with regard to the effect of heparin and epinephrine, induction, form, and duration of cardiac arrest as well as duration of CPR is often very different; comparisons are therefore difficult to make. During CPR ventilation is monitored using ventilatory pressure, frequency, tidal volume, and arterial blood gases. Thorax compressions are characterized by frequency, direction (sagittal, transversal), technique (mechanical, manual), relationship of time between compression and relaxation (50:50, 40:60), and depth of compression (power used, esophageal pressure, arterial blood pressure). Effects of CPR techniques are demonstrated during CPR by cardiovascular parameters. In addition to recording of blood pressure and blood flow, examination of regional perfusion rates using radioactive microsphere techniques is common. 24-h surveillance and extensive neurological tests are carried out during recovery following CPR.

Anesthesia↗