Intravenous anesthesia involves injecting drugs directly into the bloodstream to accomplish certain anesthetic goals like rendering a patient unconscious, reducing reflex response, calming stress or others. Very often, this term is used to refer to general anesthesia, frequently required during surgery to promote total unconsciousness of a patient. Such anesthesia is often given by means of a well-controlled intravenous drip, in which medicines and other solutions like fluid slowly drip into an intravenous catheter connected to a vein. Sometimes a single dose of intravenous anesthesia is given by injection straight into a vein instead, and doesn’t need to produce total unconsciousness.
It’s easy to contrast intravenous anesthesia to other methods of providing different levels of sedation or pain control. A noted alternative is anesthesia provided by oral route, which may be used in many settings. One difference between these two types is that any anesthetic directly injected into a vein immediately is in the bloodstream, so it is both faster, and available in larger supply.
Another form of anesthesia can be inhaled, and this usually faster-acting than oral routes with greater bioavailability, since it reaches the bloodstream more quickly. Some people might have more than one type of anesthetic prior to surgery and could possibly inhale some medicines, have an intravenous or IV drip that delivers others and possibly take something orally before a procedure. If additional medications are needed, they might even be injected instead of administered via IV drip.
There are different goals of anesthesia and different types of medicines used in intravenous anesthesia. Some of the goals of anesthesia are to produce amnesia and unconsciousness, to dull reflex response (areflexia), and to remove sensation of pain. These three goals when taken together are sometimes called total intravenous anesthesia (TIVA). A fourth goal of reducing anxiety is often added.
To achieve TIVA, different medications are mixed together in precise ways. Types of medicines used can include drugs like benzodiazepines, barbiturates, opioids, analgesics like non-steroidal anti-inflammatory drugs, a variety of muscle relaxants and dissociative anesthetics like ketamine or other anesthetics like propofol. The exact combination of what people receive depends on how many parts of TIVA are required for the procedure and also on a person’s medical history, experience with anesthesia in the past, and anesthesiologist preference. Dosing also takes into account a person’s size, age and other factors.
In most cases, this makes intravenous anesthesia a highly individualized and selective process that depends on numerous elements. Patients may also have some choice about types of anesthetic they’d like to receive. Some procedures are done with minimal anesthetic and others can employ either sleeping sedation or full general anesthesia. Patients may be asked by physicians to decide on how much sedation level they desire, usually knowing that if sedation level is not adequate, additional anesthetics could be given. If intravenous anesthesia is already established during a procedure, additional medicines can usually be easily added to the intravenous drip.