Anesthesiology and Intensive Care

  Propofol and thiopental sodium are both intravenous anesthetic agents used for the induction of anesthesia, but there are several differences between the two agents: Onset and duration of action: Propofol has a more rapid onset of action compared to thiopental sodium, meaning it takes effect more quickly after administration. Propofol also has a shorter duration of action compared to thiopental sodium, which allows for quicker recovery after the procedure. Mechanism of action: Propofol works by enhancing the activity of the inhibitory neurotransmitter GABA, while thiopental sodium enhances the activity of GABA and also inhibits the excitatory neurotransmitter glutamate. Cardiovascular effects: Propofol has a dose-dependent decrease in blood pressure and can cause vasodilation, while thiopental sodium has less of an effect on blood pressure and can cause less vasodilation. Antiemetic properties: Propofol has antiemetic properties, meaning it can reduce the incidence of nausea an...

Anatomical Sites of Action General anaesthetic agents affect both brain and spinal cord to account for physiological responses to nociception, loss of consciousness and inhibition of explicit memory. Auditory and sensory evoked potential data implicate the thalamus as the most likely primary target, but secondary sites such as the limbic system (associated with memory) and certain cortical areas are also

  Generally, in obese patients, the blood distributes more to nonadipose than to adipose tissues, resulting in higher plasma drug concentrations in obese patients with mg/kg dosing than in normal patients with less adipose mass. ➡

Propofol-related Infusion Syndrome is an acute refractory bradycardia leading to asystole and one or more of: Metabolic acidosis (base deficit > 10 mmol.l(-1)) Rhabdomyolysis Hyperlipidaemia Enlarged or fatty liver Risk Factors: Assosiated with propofol infusions at doses higher than 4 mg/kg/h  for greater than 48 h duration. Young age Low carbohydrate intake Corticosteroids intake Catecholamine infusion Pathogenesis:      Unclear, but may be associated with    impaired mitochondrial fatty acid metabolism,  mediated by propofol.   Clinical signs: Hemodynamic instability Requirement of  inotrope support Green urine ECG: right bundle branch block with convex-curved ('coved type') ST elevation in the right praecordial leads (V1 to V3). Blood gases: lactic acidosis;  Electrolytes: hyperkalaemia (in case of rhabdomyolysis, acute kidney failure) Lipaemic serum Treatment: ...

Propofol was discovered in the Biology Department at ICI Pharmaceuticals Division (now  AstraZeneca )  in the UK (1977)

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Different clinical scenarios lend themselves to the use of certain induction agents when rapid sequence intubation (RSI) is needed. Head injury or stroke   —  In the patient with potentially elevated intracranial pressure (ICP) from head injury or stroke or other conditions, adequate cerebral perfusion pressure must be maintained to prevent secondary brain injury. This means avoiding elevations in ICP and maintaining adequate mean arterial pressure. For these reasons, etomidate or ketamine are used for induction of these patients. If the patient is hypertensive at the time of induction, etomidate is preferable, as it will not further elevate the blood pressure. In normotensive or hypotensive patients, either agent can be used. In the severely hypotensive patient, ketamine is preferable. Ketamine's analgesic effects minimize the adverse sympathetic stimulation of laryngoscopy, while etomidate lacks such effect. Pretreatment with a low do...