Inhalation Anesthesia: Today and Tomorrow

All potent anesthetics today possess inherent toxicity. Consequently, a progressive decrease in central nervous system activity is also accompanied by equivalent or greater decrease in some other major organ system function (respiratory, cardiovascular, renal, etc.). Therefore, in my opinion, the secret to the safe administration of anesthetics in the clinical setting is careful titration of the drug against the anesthetic effect desired. For this reason, inhalation anesthetics will continue to occupy an important part of the anesthetist’s armamentarium for the foreseeable future. There are no other drugs whose effects can be reversed by removing the drug from the body in a short period of time. The limited solubility of clinically useful inhalation anesthetics allows such removal by ventilation of the lungs with a drug-free mixture, thus reversing the gas pressure gradient which was responsible for the induction of the anesthetic state in the first place. Although there is some evidence that the acute toxicity of all potent inhalation anesthetics at the present time is somewhat greater than intravenous drugs, this remarkable ability to either increase the effect of the anesthetic by increasing anesthetic delivery through the lungs or, more importantly, to decrease or abolish the effect by ventilating the anesthetic out of the body is a very notable property of these drugs.