Influences of low dose volatile anesthetic agents on ventilatory control in humans: a comparison of the Knill and Leiden studies

Abstract

Knowledge on the effects of low- and high-dose volatile anesthetic agents on ventilatory control is import since it influences, at least partly, the clinical management of all patients. It concerns patients during general anesthesia that breathe spontaneously, most postoperative patients after general anesthesia, patients during Monitored Anesthesia Care and patients during labor and dental surgery that require anesthesia and analgesia. Spontaneous respiration during general anesthesia remains popular because of its many advantages: the patient regulates his/her own anesthetic depth, the occurrence of awareness is uncommon, immediate transportation after deep extubation to the Anesthesia Care Unit is possible and there is no need for reversal of muscle relaxants. Disadvantages are respiratory depression, delayed recovery, the risk of upper airway obstruction and aspiration. Some of these may be of lesser importance when using an anesthetic with a low blood-gas partition coefficient that ensures rapid emergence. Sevoflurane and desflurane are examples of new generation halogenated anesthetic agents with such rapid pharmacokinetic characteristics. Lately, the number of patients breathing spontaneously during general anesthesia has increased even more due to the introduction of the Laryngeal Mask Airway.