PROPOFOL

Propofol is a short acting intravenous sedative-hypnotic. Propofol has several advantages over other anesthetic agents.

The main advantages of propofol include

1.  rapid induction of general anesthesia

2.  rapid return of consciousness

3.  minimal residual effect on the central nervous system

4.  decreased incidence of nausea and vomiting.

Use:

1.  as an anesthetic induction agent

2.  maintenance of general anesthesia

3.  for short term sedation in intensive care patients that are intubated and mechanically ventilated.

Propofol is formulated in an emulsion as a1% solution. The emulsion contains soybean oil, glycerol, and egg lecithin (derived from egg yolk).The emulsion may cause pain with injection. The emulsion supports bacterial growth and strict aseptic technique must be carried out. When a vial is opened the contents should be used within 6 hours. The rest of the contents should be discarded. Never share the same medication with other patients. The date and time, of when propofol was drawn up, should be recorded on the syringe to avoid administering it after 6 hours.

Effects:

• Propofol interacts with gamma-aminobutyric acid (GABA), the principle inhibitory neurotransmitter in the central nervous system.

• The high lipid solubility of propofol is responsible for its rapid onset. Propofol has ashort distribution half life, allowing for rapid awakening.

• The liver is responsible for removing and metabolizing propofol. The kidneys are responsible for excreting the metabolites.

• Onset of action for propofol is 40 seconds.

The peak effect is 1 minute.

The duration ofaction is 5-10 minutes.

• The effects of propofol on the cardiovascular system include a decreased systemicvascular resistance (vasodilatation), decreased contractility of the heart, and decreased preload. These factors cause a decrease in blood pressure. Severe hypotension may be seen in patients who are dehydrated, actively bleeding, elderly, and/or those with poorheart function.

• The effects of propofol on the respiratory system include a dose dependant depression of ventilation and apnea.

Propofol can easily and rapidly cause an airway obstruction. It also alters the normal respiratory responses to hypoxia and hypercarbia. When administering propofol airway equipment should be immediately available including a bag-mask-valve device or anesthesia circuit, oral airways, oxygen, and intubating equipment.

• Propofol solutions that contain sulfites as a preservative should not be administered to asthmatic or actively wheezing patients. Sulfites can cause bronchoconstriction.

• Propofol may cause spontaneous movements and movements that look like tonic-clonicseizures.

• Pain is often associated with injection. A large vein should be used. Smaller veins, such as those on the dorsum of the hand, are often associated with pain. To reduce pain 2 -5 ml of 1% lidocaine can be administered immediately prior to the induction dose ofpropofol.

• Reduced doses should be used in the elderly and those that are dehydrated.

Dose:

• Adults: 2-2.5 mg/kg slowly over 30 seconds for induction of anesthesia.

For maintenance ofanesthesia a continuous infusion of 0.1-0.2 mg/kg/min or alternatively intermittent bolus of20-50 mg

.• Children: 2.5-3.5 mg/kg slowly over 30 seconds for induction of anesthesia.

For maintenance of anesthesia a continuous infusion of 0.125-0.3 mg/kg/min. Contraindications:

• Do not use in hemorrhaging patients.

• Do not use in patients with poor heart function.

• Do not use in patients that are allergic to egg yolks and soy products.

• Administration of propofol for cesarean section may be associated with neonatal depression.

• Not recommended for patients with increased intracranial pressure.