An analysis of the subjective pungencies of inhalational anesthetics.

Selection of an inhalational anesthetic is often based upon anecdotal reports suggesting that certain drugs are "less pungent," "smoother" and better tolerated during certain inhalant techniques. The authors tested the hypothesis that there would not be demonstrable preference for the inhalant halothane over the modern ether-based agents. Results suggest that (1) agent selection should be based upon physiopharmacological criteria rather than alleged patient acceptance, and (2) technique and experience in use are the primary factors predicting efficaciousness. When gaseous anesthetics are employed for anesthetic induction and maintenance, it is important that they be non-irritating and rapidly produce desired alveolar concentrations. Reports of the incidence of undesirable reflex activity, such as coughing, breath-holding and laryngospasm, are highly variable. Generally halothane (H) is preferentially employed over enflurane (E) or isoflur-ane (I) for inhalation induction as it is considered to be the least irritating and pungent and best received by patients. 1. 2 This practice appears to be primarily anecdotal in nature. Controlled studies of olfaction and patient acceptance are lacking. Selection of an inhalant for clinical use is a multidimensional process with factors such as experience and technique being largely responsible for the reported differences among the agents utilized. It has been shown that induction/emergence times are either similar or better with the modern ethers when H, E and I have been compared. 3-5 Both E and I have been shown usable with pedi-atric mask inductions, extending the pharmaco-logic advantages of these agents to all patients. 0 " 7 These studies are tempered by reports that the reflex response to the pungency of I represents a major drawback to the induction and maintenance of anesthesia with this drug.. 2 ' s-11 The authors' experience with I as an induction agent in adults and children has been favorable and differs markedly from the unsatisfactory reports of other investigators. I is preferentially employed by the authors over other inhalants because of its significant physical-chemical, pharmacological and physiological advantages. 12-15 The authors tested the hypothesis that there are no significant differences in the perceived pungencies of the inhalation anesthetics H, E or I in a healthy young adult population. Methodology Three hundred individuals aged 17 to 41, in excellent health and free from deficits of olfaction, participated in the investigation. There were 178 males and 122 females. Participants were selected at random from a non-medical population at large. Each individual received a brief explanation as …