Propofol nervous system

Unlike isoflurane, desflurane may stimulate the sympathetic nervous system at concentrations above 1 MAC. Sudden and unexpected increases in arterial blood pressure and heart rate have been reported in some patients, accompanied by increases in plasma catecholamine and vasopressin concentrations and increased plasma renin activity. These pressor effects may increase morbidity or mortality in susceptible patients. The mechanism of sympathetic activation is unclear but does not appear to be baroreceptor-mediated. Clonidine, esmolol, fentanyl and propofol partially block the response but lignocaine (lignocaine) is ineffective. 

Seizures induced by local anesthetics can also be treated with small doses (given intravenously) of thiopental 1-2 mg/kg, propofol 0.5-1 mg/kg, midazolam 2-4 mg total dose, or diazepam 0.1 mg/kg. The muscular manifestations of seizures can be suppressed by a short-acting neuromuscular blocking agent (eg, succinylcholine, 0.5-1 mg/kg IV). It should be emphasized that succinylcholine does not obliterate central nervous system manifestations of seizure activity. Rapid tracheal intubation and mechanical ventilation can prevent pulmonary aspiration of gastric contents and facilitate hyperventilation therapy. 

Central nervous system. Propofol causes dose-dependent cortical depression and is an anticonvulsant. It depresses laryngeal reflexes more than barbiturates, which is an advantage when inserting a laryngeal mask airway. 

Propofol is a cardiodepressant and resets the baroreflex set-point, with a tendency to bradycardia (which occurs in some 5% of cases), hypotension (16%), or both (1.3%) (8). The hypotension may be brought about by peripheral vasodilatation, reduced myocardial contractility, and inhibition of sympathetic nervous system outflow (9). Four deaths due to cardiovascular collapse during induction have been reported in patients aged 78-92 years given propofol 1.1-1.8 mg/kg (10). The patients were of ASA classes 3 or 4. 

Propofol causes bradydysrhythmias by reducing sympathetic nervous system activity. 

At the molecular level intravenous anaesthetics interact mainly with GABAa receptors (thiopental, propofol...) or with other ligand-gated ion channels (ketamine) synthetic opioids (phentanyl congeners) act in a more specific way as agonists of p-opioid receptors. However, all the anaesthetics, in addition to their action at the level of central nervous system, have also a variety of effects at other levels in particular, a temporary impairment of the immune system involving phagocytes can be induced. 

Nervous System The CNS effects of propofol are similar to those of barbiturates, but, unlike thiopental, propofol is not a proven acute intervention for seizures. 

Nervous system Although propofol has anticonvulsant action it can rarely cause seizures [78 ]. 

NERVOUS SYSTEM A case report describes a healthy male patient who developed involxmtary movements of the arms and head after exposure to fentanyl [31 ]. In a randomised controlled trial of 112 children undergoing anaesthesia, 14.9% experience emergence delirium after fentanyl/propofol anaesthesia as compared to 38.9% receiving sevoflurane [32 j. 

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