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Biomedical subjects

M Pinaud

Publications and source records attributed to M Pinaud.

174 records · Page 10Linked to original sources

[Hypotension induced by molsidomine or trinitroglycerin].

Molsidomine--a new vasodilator agent with predominant venous effect--is used for the treatment of coronary artery disease. Haemodynamic effects of i.v. molsidomine (300 micrograms X kg-1) during deliberate hypotension were investigated in 11 dogs and compared with nitroglycerin-induced-hypotension, at the same decrease in MAP (-25%). Hypotension was only obtained in 5 dogs with both drugs. Hypotension resulted from decrease in stroke volume due to a decrease in preload. Decrease in systemic vascular resistance and tachycardia were less important with molsidomine than with nitroglycerin. After molsidomine MAP decreased progressively over 30 minutes.

Animals↗

[Bilateral adrenal pheochromocytoma associated with pregnancy. Simultaneous cesarean section and adrenalectomy].

An-25-year-old primigravida with bilateral phaeochromocytomas was managed from 6 weeks' gestation until 2 years following combined caesarean section and removal of adrenal tumours. Preoperative alpha-blockade was achieved by oral prazosin without deleterious effects. Intraoperative management comprised neuroleptanalgesia, arterial and pulmonary pressures monitoring, adequate heart loading with fluid replacement and sodium nitroprusside. Postoperatively mother and baby remained normotensive.

Adrenal Gland Neoplasms↗

[Deep hypotension induced by sodium nitroprusside in neurosurgery. I.--Systemic hemodynamic effects (author's transl)].

The systemic hemodynamic effects of deep hypotension (MAP: 38 +/- 6 mm Hg) induced by sodium nitroprusside (S.N.) were studied in 20 patients who underwent surgery for cerebral aneurysm. The hemodynamic measurements were performed four times.: (1) during the preoperative period, (2) during stable anesthesia just before hypotension, (3) during stable hypotension, (4) 20 minutes after stopping nitroprusside. All patients were mechanically ventilated with a constant tidal volume and rate. Parameters for acid-base balance and Pa O2 were also recorded. Nitroprusside produces arterial and venous dilatation which results in a decrease of afterload and preload. The mean dosage of S. N. was 18 mcg/kg/mn. Systemic vascular resistances decreased by 62 p. cent. Mean arterial pressure decreased by 53 p. cent; it reached 40 mm Hg. Fall in preload resulted in a decrease in pulmonary wedge pressure by 28 p. cent. This fall in preload produced a decrease in stroke index according to Frank-Starling's mechanisms. However tachycardia allowed a rise in cardiac index by 20 p. cent. Increase of pulmonary wedge pressure at 8-10 mm Hg by blood volume expansion maintains stroke index at control level. Under these conditions the elevation of cardiac index is due to tachycardia. Cardiac rhythm disorders (wandering pace-maker, nodal rhythm) are observed in 5 patients after having stopped nitroprusside.

Adult↗

[Deep hypotension induced by sodium nitroprusside in neurosurgery. II.--Cerebral hemodynamic effects and metabolic rate of oxygen (author's transl)].

The cerebral hemodynamic effects of sodium nitroprusside (S. N.) have been the object of animal studies mainly. During the only human study performed, the drop in mean arterial pressure (MAP) is limited to 67 mm Hg. The study of the evolution of cerebral blood flow (CBF) in cases of more severe hypotension (MAP less than 45 mm Hg) seems of some interest. The study was composed of the measurement of the CBF using Xenon 133 and the calculation of cerebral vascular resistances (CVR) as well as cerebral metabolic rate of oxygen (CMRO2). Eleven patients with an average age of 37 years underwent surgery for cerebral aneurism 10 to 15 days after the inaugural hemorrhagic accident, under narconeuroleptanalgesia and stable ventilatory conditions. They are divided into 2 groups: Group I, 9 patients with normal levels of consciousness; Group II, 2 patients either agitated or obnubilated. The study is composed of 3 successive measures: (1) (T0) during stable anesthesia just prior to hypotension; (2) (T1) after 5 minutes of hypotension (MAP = 40 +/- 7 MM Hg); (3) (T2) 20 minutes after having stopped S. N. infusion. For the 9 patients in Group I, CBF remains unchanged at T1, the CVR decreases (p less than 0.001) and CMRO2 decreases (p less than 0.05). At T2 all of these parameters return to T0 values. The postoperative clinical evolution is favorable and uncomplicated. For the 2 patients in Group II the CBF, initially higher, falls from 20 to 30 p. cent at T1 with a drastic reduction in CMRO2. Despite the improvement of these parameters at T2, a prolonged postoperative coma is observed. This study suggests that CBF and CMRO2 are important parameters to monitor during controlled severe hypotension. Decrease in MAP must be less than 50 p. cent of control value and time-limited.

Acid-Base Equilibrium↗