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Biomedical subjects

R Souron

Publications and source records attributed to R Souron.

At least 109 records · Page 6Linked to original sources
PubMedDate not supplied

[Holter registration in ophthalmic surgery in adults. Peroperative arrhythmia under halothane or enflurane].

In 100 adult patients undergoing ophthalmic surgery under halothane or enflurane anaesthesia, the electrocardiogram was recorded on magnetic tape and analyzed subsequently for arrhythmias using a high-speed analyzer. Enflurane induced a much less premature atrial contractions (kappa 2 = 4.75; p less than 0.05) and a nodal rhythms (kappa 2 = 4.39; p less than 0.05) than halothane. There were no significant differences between the two drugs in the frequency of premature ventricular contractions and wandering pace maker. Our results confirm those of previous studies during oral surgery that enflurane produced significantly fewer arrhythmias than halothane. The lower incidence of cardiac dysrhythmias and the preservation of cardiovascular stability suggest that enflurane may be the agent of choice for this kind of surgery.

Adult↗
PubMedDate not supplied

[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↗
PubMedDate not supplied

[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↗
PubMedDate not supplied

[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↗