Introduction to Use of Intravenous Anesthesia
Introduction to Use of Intravenous Anesthesia
Many different hypnotic drugs are currently available for use during intravenous (IV) anesthetic (Thiopentone, propofol, midazolam, Ketamine, benzodiazepines and others. However, it is clear that the ideal IV anesthetic is yet to be developed. Advantages of intravenous anesthesia include rapid and smooth induction of anesthesia, little equipment requirement (syringes, needles, catheters), and easy administration of drugs. Disadvantages include difficult retrieval of drug once administered, less control of depth and duration of anesthesia, lack of ventilatory support, and poor tolerability in debilitated and dehydrated patients.
The ideal characteristics of intravenous anesthetic agents include the following:
- High therapeutic index
- No toxic metabolites
- Non-cumulative
- Potent, so small volume is required for anesthetic induction/maintenance
- Long shelf life and resistance to microbial contamination
- Compatible with other drugs
- Quick and smooth induction and recovery
- Reversible with specific antagonist
- Non-allergenic
- No cardiopulmonary depression
- Independent of liver and kidneys for metabolism and excretion
- No pain on injection
- Inexpensive.
Ideally there is no such drug that has all, the above characteristics, therefore to achieve the ideal characteristics drugs are combined, titrated, tested...