Intraoperative EEG changes in relation to the surgical procedure during isoflurane-nitrous oxide anesthesia: hysterectomy versus mastectomy.

Study Objectives: To investigate topographical changes in electroencephalographic (EEG) frequencies and spectral power density in relation to different surgical procedures (abdominal hysterectomy versus mastectomy) during steady-state isoflurane-nitrous oxide (N2O) anesthesia.

Design: Prospective, nonrandomized, open study.

Setting: University hospital.

The effects of surgical stimulation on intracranial hemodynamics.

This study investigates the effects of surgical stimulation on cerebral blood flow velocity using transcranial Doppler sonography (TCD) in 1 and 2 maximum alveolar concentration (MAC) isoflurane anesthetized patients. Sixty ASA I and II patients undergoing breast surgery were studied. Anesthesia was maintained with 0.

Sevoflurane improves neurological outcome after incomplete cerebral ischaemia in rats.

We have studied the effects of sevoflurane on neurological outcome in a rat model of incomplete cerebral ischaemia. After institutional approval, 30 non-fasted male Sprague-Dawley rats (455-555 g) were anaesthetized, the trachea intubated and the lungs ventilated mechanically with isoflurane and 30% oxygen in air. Catheters were inserted into the right femoral artery, both femoral veins and into the right jugular vein for measurement of arterial pressure, drug administration and blood sampling.

Transcranial Doppler sonography indicates critical brain perfusion during hemorrhagic hypotension in dogs.

This study investigated the effects of hemorrhagic hypotension on cerebral blood flow velocity and brain electrical activity (by electroencephalogram [EEG]). Eleven mongrel dogs were anesthetized with isoflurane (1 minimum alveolar anesthetic concentration [MAC]) and catheters were placed into both femoral arteries and veins for mean arterial blood pressure (MAP) measurement, blood withdrawal, and drug administration. Brain temperature, arterial blood gases, and pH were maintained constant.

Surgical stimulation increases median nerve somatosensory evoked responses during isoflurane-nitrous oxide anaesthesia.

Median nerve somatosensory evoked responses (MnSSER) were recorded in 15 healthy adult patients, ASA I-II, before and during orthopaedic surgery. After induction of anaesthesia with fentanyl 0.1-0.

[Enflurane blocks ion current through the nicotinic acetylcholine receptor].

Aim: The study investigates the influence of enflurane (EN) on macroscopic currents of the nicotinic acetylcholinergic receptor channel (nAChR). This ion channel is a representative member of the superfamily of ligand-gated receptor channels and is better characterized than all the other receptors in respect of structure and function.

Methods: For the experiments the patch-clamp technique was used to study the embryonic type of the nAChR expressed by cultured mouse-myotubes.

Effects of sufentanil on cerebral hemodynamics and intracranial pressure in patients with brain injury.

Background: The current study investigates the effects of sufentanil on cerebral blood flow velocity and intracranial pressure (ICP) in 30 patients with intracranial hypertension after severe brain trauma (Glasgow coma scale < 6).

Methods: Mechanical ventilation (FIO2 0.25-0.

Tumor oxygenation in a transplanted rat rhabdomyosarcoma during fractionated irradiation.

Purpose: To quantify the changes in tumor oxygenation in the course of a fractionated radiation treatment extending over 4 weeks.

Methods And Materials: Rhabdomyosarcomas R1H of the rat were irradiated with 60Co-gamma-rays with a total dose of 60 Gy, given in 20 fractions over 4 weeks. Oxygen partial pressure (pO2) in tumors was measured at weekly intervals using polarographic needle probes in combination with a microprocessor-controlled device (pO2-Histograph/KIMOC).

Electrophysiological monitoring and mild hypothermia.

Hypothermia affects cerebral metabolism including a variety of neurotransmitter systems. Neurophysiologic changes during hypothermia are characterized by decreases in the membrane resting potential and amplitude. The duration of the action potential is prolonged and nerve conduction velocity is decreased.

[Propofol-alfentanil reduced cerebrovascular CO2 reactivity in comparison with isoflurane].

The present study compared the effects of propofol/alfentanil versus isoflurane anaesthesia on cerebral vascular reactivity to changes in carbon dioxide (CO2) using transcranial Doppler sonography (TCD). METHODS. Seventeen ASA class I patients undergoing minor elective surgery were studied following IRB approval and informed consent.

Neuroprotection: fact or fantasy?

Several strategies have been proposed for protecting the brain from ischaemic and hypoxic insults, based on an understanding of the pathophysiological processes involved. They include hypervolaemic haemodilution, anaesthesia, hypothermia, normoglycaemia, calcium channel blockers, adenosine modulators, NMDA- and AMPA-receptor antagonisms and lazeroids. Some have only been shown to be effective in animals and some have clinical relevance.

Effect of renal function on neuromuscular block induced by continuous infusion of mivacurium.

We have studied the effect of renal function on the pharmacodynamics of mivacurium. Sixty patients were allocated to three groups according to creatinine clearance: group C (control), creatinine clearance > 50 ml min-1; group P (preterminal renal failure), creatinine clearance < 50 ml min-1 > 20 ml min-1; group T(terminal renal failure), creatinine clearance < 20 ml min-1. Neuromuscular transmission (train-of-four) was monitored using electromyography from the hypothenar muscle with stimulation of the ulnar nerve.

[Ketamine and evoked potentials].

Ketamine-induced changes in the spontaneous and evoked electroencephalogram have been well documented in animals and humans. In contrast to the action of hypnotics, ketamine does not result in a dose-dependent suppression of neural activity. Many studies have revealed excitatory activity with induction of synchronized high-voltage slow waves in the electroencephalogram (EEG).

Surgical stimulation induces changes in brain electrical activity during isoflurane/nitrous oxide anesthesia. A topographic electroencephalographic analysis.

Background: The aim of this study was to investigate topographic changes in electroencephalographic (EEG) power and frequency induced by abdominal surgery during anesthesia with 0.6% or 1.2% isoflurane in 66% nitrous oxide.

[Expert systems in medicine: possible uses in anesthesia].

The euphoric assumption that powerful computers fed with sophisticated software programmes may serve as a substitute for human knowledge and decision making has been replaced by a more realistic concept of how computers may help in collecting data and their interpretation on the basis of human knowledge and experience. The computer is now used as a dedicated tool to support man in overtaking cumbersome and monotonous processes and tedious calculations. Running 24 hours a day, a specific feature of the computer is that depending on unequivocal software programmes it does neither forget or alter commands and information.

Improvement of brain electrical activity during treatment of porcine malignant hyperthermia with dantrolene.

Three months before this study, susceptibility for malignant hyperthermia (MH) had been tested in 15 pigs. In all pigs, MH was triggered by administration of 1% halothane. Brain electrical activity was examined during therapy of MH with and without administration of dantrolene.

Cerebral blood flow and cerebral blood flow velocity during angiotensin-induced arterial hypertension in dogs.

Pressure-passive perfusion beyond the upper limit of cerebral blood flow (CBF) autoregulation may be deleterious in patients with intracranial pathology. Therefore, monitoring of changes in CBF would be of clinical relevance in situations where clinical evaluation of adequate cerebral perfusion is impossible. Noninvasive monitoring of cerebral blood flow velocity using transcranial Doppler sonography (TCD) may reflect relative changes in CBF.

Cerebral blood flow velocity in relation to cerebral blood flow, cerebral metabolic rate for oxygen, and electroencephalogram analysis during isoflurane anesthesia in dogs.

The purpose of this study was to correlate changes in cerebral blood flow velocity (Vmean) with cerebral blood flow (CBF) during isoflurane anesthesia in dogs. The relation between cerebral oxygen consumption (CMRO2) and electroencephalogram (EEG) analysis also was investigated. Blood flow velocity was measured in the middle cerebral artery using a pulsed transcranial Doppler (TCD).

The effects of propofol on cerebral and spinal cord blood flow in rats.

The effects of low and high doses of propofol on global cerebral blood flow (CBF) and spinal cord blood flow (SCBF) as a function of mean arterial blood pressure were investigated. CBF and SCBF during propofol infusion were compared to the levels in rats anesthetized with nitrous oxide (N2O) and fentanyl. Rats in the fentanyl/N2O group (control, n = 13) received 70% N2O in O2 plus fentanyl (bolus: 10 micrograms/kg; infusion: 25 micrograms.