It is reported that 17% of gastrointestinal (GI) units in the United States use propofol in endoscopy, and 43% of units considered using propofol in 2005. The advantages of this method may include rapid induction and recovery, and improving the comfort of patients and doctors. However, these benefits come at a cost. Many GI units in Canada are satisfied with the benzodiazepines and narcotics they currently use. Can you review the characteristics of propofol?
Propofol is a kind of isopropyl phenol, which is injected intravenously as a 1% solution for inducing anesthesia or as an intravenous sedative. It was introduced in the mid-1980s and has been used in hundreds of millions of operations worldwide. It is speculated that propofol is γ The interaction of aminobutyric acid receptor (the main inhibitory neurotransmitter in the brain) plays a role. Propofol is rapidly removed from the blood circulation when administered intravenously. Its clearance may enter the lungs through redistribution, and more importantly, the liver. Only 0.3% of the dose was excreted unchanged through urine. The elimination half-life of propofol is about 0.5 to 1.5 hours. The clearance rate of this drug is very fast, so it can be continuously injected or repeatedly injected without any cumulative effect. Propofol has been used as the first choice drug for inducing anesthesia and intravenous sedation.
In healthy adults, the total anesthetic dose of propofol for intravenous induction or deep sedation is 1.5 mg/kg to 2.5 mg/kg, which should be reduced by 50% in the elderly or frail patients. Within 10 to 15 minutes after stopping the administration, consciousness will recover. If auxiliary drugs such as fentanyl and midazolam are not used or in very small doses.
Propofol has a quick recovery, less residual sedation, and low incidence of nausea and vomiting, making it the first choice for conscious sedation in outpatient anesthesia. Continuous intravenous injection of propofol (25 μ g/kg/min ~ 100 μ G/kg/min). The patient usually recovers within 5 - 10 minutes after drug withdrawal. If the clinician chooses to use adjuvant drugs, such as midazolam and fentanyl, the recovery period may be prolonged. In addition to this sedative and hypnotic effect, propofol also provides some antiemetic and antipruritic effects. It has no analgesic effect.
The most common side effect of propofol is hypotension caused by peripheral vasodilation. Peripheral vasodilation is mainly due to the reduction of sympathetic outflow from the central nervous system. Propofol may produce some negative inotropic effects due to the decrease of intracellular calcium availability. During the use of propofol, there is a risk of death associated with bradycardia, with 1.4 deaths reported per 100000 patients. Propofol also produces a dose dependent ventilatory depression, resulting in apnea in approximately 25% - 35% of patients. Other co inducers and anesthetics, such as midazolam and fentanyl, may enhance this ventilatory inhibition. Other minor side effects include injection pain, which can be alleviated by simultaneous or pre intravenous administration of docaine. Propofol also promotes bacterial growth; Therefore, the drug cannot be stored for more than 4 hours after being prescribed. At present, there is no known propofol reversal agent.
