Measurement of cerebral blood flow and volume with positron emission tomography during isoflurane administration in the hypocapnic baboon.

Using positron emission tomography, cerebral blood flow (CBF) and cerebral blood volume (CBV) were measured after the addition of isoflurane (1.3 vols %, end-tidal concentration) to neuroleptanesthesia (fentanyl/droperidol) in hypocapnic baboons. The study was designed to determine whether isoflurane, when administered during hypocapnia, acted as a cerebral vasodilator to increase either CBF or CBV.

Pulling versus guiding: a modification of retrograde guided intubation.

We describe a modification of retrograde guided intubation. With the help of a gliding knot fixed around the side hole of the tracheal tube, we use the catheter to pull and guide the tracheal tube down the larynx and trachea. The technique offers several advantages: it is surprisingly fast, relatively atraumatic, easy to perform, and eliminates most causes of failure.

Changes in CSF pressure after mannitol in patients with and without elevated CSF pressure.

In view of the current concern that rapid infusion of mannitol might initially aggravate intracranial hypertension, the effects of a mannitol infusion on lumbar cerebrospinal fluid pressure (CSFP) were investigated in 49 patients. The studies were performed when the patients were under general anesthesia prior to elective craniotomy for tumor resection or intracerebral aneurysm clipping. The patients were divided into two groups: 24 patients with normal CSFP (Group I, mean CSFP 10.

Cerebral blood volume is increased in dogs during administration of nitrous oxide or isoflurane.

Positron emission tomography was used to study the effects of nitrous oxide (N2O) and isoflurane on regional cerebral blood volume (rCBV) in dogs during normocapnia and hypocapnia. Regional cerebral blood volume was measured serially during the addition of 50% N2O to a background anesthetic of fentanyl in normocapnic (group 1) and hypocapnic (PaCO2 25 mmHg, group 2) dogs. In each group, after 15 min of N2O administration accompanied by rCBV measurement, elimination of N2O with 100% O2 was continued for 15 min.

Does a bolus of mannitol initially aggravate intracranial hypertension? A study at various PaCO2 tensions in dogs.

In two groups of anaesthetized dogs, with (n = 28) or without (n = 28) induced intracranial hypertension, we compared the effects on intracranial pressure (ICP) of the rapid administration of mannitol 2 g kg-1 i.v. at PaCO2 2.

Selective neuromuscular blockade for intraoperative electrocorticography.

Local anesthesia is advocated for cortical mapping in certain neurological procedures. Occasionally, however, a modified general anesthetic is necessary. We describe a technique of balanced anesthesia in which the arm opposite to the craniotomy is selectively isolated from the effect of the neuromuscular blocking agent and hence preserves its motor response to cortical stimulation.

Effects of rapid mannitol infusion on cerebral blood volume. A positron emission tomographic study in dogs and man.

Positron emission tomography was used to study the effect of a rapid infusion of mannitol on cerebral blood volume (CBV) in five dogs and in three human subjects. The ability of mannitol to reduce intracranial pressure (ICP) has always been attributed to its osmotic dehydrating effect. The effects of mannitol infusion include increased osmolality, total blood volume, central venous pressure (CVP), and cerebral blood flow, and decreased hematocrit, hemoglobin concentration, serum sodium level, and viscosity.

The effects of rapid infusions of saline and mannitol on cerebral blood volume and intracranial pressure in dogs.

The role of osmotic brain dehydration in the early reduction of intracranial pressure (ICP) following mannitol administration has recently been questioned and a decrease in cerebral blood volume (CBV) proposed as the mechanism of action. To evaluate this hypothesis, relative CBV changes before and after mannitol infusion were determined by collimated gamma counting across the biparietal diameter of the exposed skull in six dogs. Red blood cells were labelled with chromium-51.

Anaesthetic considerations in percutaneous radiofrequency coagulation of the Gasserian ganglion.

This study determined the cardiovascular effects of percutaneous radiofrequency coagulation of the Gasserian ganglion, performed under neuroleptanalgesia and intermittent ultrashort-acting barbiturate anaesthesia. Twelve ASA physical status class II patients were studied. Highly significant increases in mean heart rate and arterial blood pressure followed the insertion of the cannula electrode into the Gasserian ganglion (p less than 0.

Use of hypertension and electroencephalographic monitoring during carotid endarterectomy.

Intraoperative hypertension and continuous electroencephalographic (eeg) monitoring were used during 42 carotid endarterectomies performed on 37 patients from 1970 to 1978. Computer spectral analysis of a majority of the electroencephalograms was also performed. Under supplemented nitrous oxide general anesthesia, elevation of the mean arterial blood pressure to 20% above the individual's preoperative mean blood pressure resulted in reversal to normal of an ischemic EEG pattern in 19% of the patients.

[Arterial hypotension induced by artificial cardiac pacing under general anaesthesia (author's transl)].

A case of haemodynamic decompensation is reported in a patient with a sick-sinus syndrome on a demand cardiac pacemaker, under-going surgery under general anaesthesia. While systemic arterial blood pressure showed adequate stability under the patient's own sinus drive, it consistently fell by 15 to 20 p. cent when artificial pacing was established.

Aetiology and control of cardiovascular reactions during trans-sphenoidal resection of pituitary microadenomas.

Two groups of 12 patients were studied to determine the causes of hypertension during trans-sphenoidal resection of pituitary microadenomas. Two concentrations of lidocaine, 0.5 and 1.

Anaesthesia for tracheal resection: a new way to manage the airway.

A case of lower tracheal resection is reported. A number 28 Foley catheter was modified and successfully used to ventilate the lungs through the short distal tracheal stump.

Reduced neuromuscular transmission safety factor in multiple sclerosis.

Regional intravascular injections of d-tubocurarine (0.3 mg) were administered in the hands of 23 normal subjects and 19 patients with multiple sclerosis. The degree of neuromuscular block and rate of recovery were determined by measuring the amplitude of the first dorsal interosseus muscle action potential which was evoked periodically by trains of five stimuli (3 Hz each) to the ulnar nerve.

[Metabolic effects of barbiturates on the anoxic brain:free radical trapping].

Different mechanisms have been proposed to explain the protector effect of barbiturates in cerebral ischemia. Among these is the particularly attractive hypothesis that the protection is obtained by an inhibition of the oxydo-reduction process in the respiratory chain in the mitochondria upstream of the Q coenzyme. Keeping this enzyme in the quinone state prevents the formation of the three radical at the level of lipoid complexes of the cellular and sub-cellular membranes, thus assuring the upkeep of the integrity of these structures.