[Value of transcranial Doppler ultrasonography in the management of severe head injuries]. / Intérêt du doppler transcrânien dans la prise en charge des traumatisés crâniens graves.

Transcranial doppler ultrasonography (TCD) is a non invasive technique for the assessment of cerebral blood flow (CBF). The aim of this prospective study was to evaluate the benefit of TCD for the monitoring of major head trauma patients. Therefore 10 of such patients, aged 17 to 37 years, had a TCD at admission and subsequently at least twice a day. Following data were measured simultaneously at the site of the right and the left middle cerebral arteries: the systolic (SV), diastolic (DV) and mean (MV) blood velocity, the resistance index (RI) of Pourcelot (RI = SV-DV/SV) and the pulsatility index (PI) of Gosling (PI = SV-DV/MV). Simultaneously, the mean intracranial pressure (ICP) obtained with a subarachnoid probe, the PaCO2 and the mean arterial pressure (Pa) were measured. The cerebral perfusion pressure (CPP) was calculated with the formula: CPP = Pa-ICP. A total of 132 measures were analysed. There was a linear relation between RI and CPP (r = 0.566; p < 0.001), between RI and ICP (r = 0.822; p < 0.001), as well as between PI and CPP (r = 0.563; p < 0.001) and between PI and ICP (r = 0.837; p < 0.001). In the opposite there was no statistically significant relation between ICP and MV (r = 0.18) nor between CPP and MV (r = 0.23). However, a MV over 100 cm.s-1 was regularly associated with a ICP over 60 mmHg. The close correlation between RI, PI and ICP allows to use RI or PI to estimate ICP.(ABSTRACT TRUNCATED AT 250 WORDS)

Heparin-associated thrombocytopenia syndrome: an underestimated etiology of adrenal hemorrhage.

A 74-year-old man developed bilateral arterial thrombosis of the lower limbs related to heparin-associated thrombocytopenia syndrome (HATS). On day 4 after thrombectomy of both limbs, abdominal pain, fever, hypotension, abdominal tenderness appeared. Acute acalculous cholecystitis was suspected and cholecystectomy was carried out although the gallbladder was not imflamed. Later on, hyponatremia in addition to the aforesaid signs suggested the diagnosis of adrenal insufficiency. Diagnosis was confirmed by low cortisol and aldosterone plasma concentration and by CT scan, which showen two enlarged adrenal glands. HATS might explain two unexpected facts: occurrence of adrenal hemorrhage during heparin therapy with coagulation tests within the therapeutic range and paradoxical thrombosis in the central vein of adrenal gland. HATS must be regarded as one cause of adrenal hemorrhage necrosis.

[Premedication with midazolam in infants. A comparison of different modes of administration]. / Prémédication par le midazolam chez l'enfant. Comparaison des différents modes d'administration.

Midazolam presents the properties of a good premedication because of its sedative and anxiolytic activity. The aim of this study, concerning 84 children, was to compare the efficacy of midazolam according to the three ways of administration: intrarectal, oral and intranasal, in reference to a group without premedication. Results have shown the superiority of intrarectal midazolam at the dose of 0.35 mg.kg-1 30 minutes before surgery. The tolerance of this way of administration is excellent and it allows a greater sedative activity compared to the control group and to the intranasal group.

[The effect of a combination of propofol and fentanyl on cerebral blood flow. A study using transcranial doppler]. / Effet de l'association propofol-fentanyl sur les flux sanguins cérébraux. Etude par doppler transcrânien.

The results of the association propofol fentanyl on the velocity of the middle cerebral artery were studied by means of a transcranial doppler on twenty ASA I patients without any intracranial pathology. Anaesthesia induction by propofol (2.5 mg.kg-1) and fentanyl (2 micrograms.kg-1) induced a significant fall of average velocities (p: 0.0001) and an increase of the resistance index (p: 0.0001) without any associated variation of mean blood pressure and CO2 expiratory fraction. These results corroborate the variations of cerebral blood flow and cerebral vascular resistances reported in the literature and give evidence, in all probability, of a cerebral autoregulation phenomenon.

[Acute renal insufficiency following a snake bite in a 3-year-old child]. / Insuffisance rénale aiguë après morsure de vipère chez un enfant de 3 ans.

Acute renal failure after viper bite is rare in France. We describe a case in a 3 years-old child, treated with peritoneal dialysis. The physiopathology and the methods of treatment are discussed.

Effects of histamine H2 receptor antagonists on acid secretion stimulated by imidazoline derivatives in isolated parietal cells.

Both the effect of imidazoline derivatives on acid secretion and the mechanism of this effect were studied in the parietal cells isolated from guinea pigs. Clonidine and tolazoline both stimulated the parietal cells to elevate the concentration of cyclic AMP and the accumulation of [14C]aminopyrine concentration dependently, although these imidazoline derivatives are known as alpha 2-adrenoceptor agonist or antagonist. These stimulatory effects were inhibited by famotidine, ranitidine and cimetidine, histamine H2 receptor antagonists. However, [3H]clonidine binding to the membrane preparations of parietal cells was not affected by these H2 antagonists and yohimbine but was inhibited by imidazoline derivatives. These results suggest that imidazoline derivatives may bind to the specific binding sites (different from H2 receptor or alpha 2-adrenoceptor) and stimulate the acid secretion of parietal cells with an increase of cyclic AMP, and that H2 antagonists may not only compete with the agonists for receptor binding but also interfere with the receptor adenylate cyclase system.