Breathing Pattern and Occlusion Pressure Waveform in Humans Anesthetized With Halothane or Sevoflurane

Abstract

To examine the ventilatory effects of sevoflurane, breathing pattern, airway occlusion pressure waveform, and the mechanical variables of the respiratory system were determined in seven subjects anesthetized with sevoflurane and in an additional seven subjects anesthetized with halothane. All patients breathed 1 MAC of anesthetic using oxygen as the carrier gas, and the measurements were performed in the absence of surgical stimulation. The durations of inspiration and expiration were significantly longer during sevoflurane than during halothane administration. Tidal volumes were larger in the sevoflurane group than in the halothane group. Occlusion pressure waveforms were also markedly different between the two groups. Occlusion pressure during the initial 300-400 ms tended to be less in the sevoflurane-anesthetized than in the halothane-anesthetized subjects. There was no evidence of an active Hering-Breuer reflex with either anesthetic. Mechanical variables of the respiratory system were essentially identical between the two anesthetics. We conclude that (a) the ventilatory effects of halothane and sevoflurane are different, (b) the difference in the respiratory timing and depth of breathing originates from the action of the anesthetics on the central respiratory neural network, and (c) the different shape of the tracheal occlusion pressure may be largely due to the different effects of halothane and sevoflurane on the muscles of the rib cage.

The Hering-Breuer reflex in anesthetized infants: end-inspiratory vs. end-expiratory occlusion technique

“…3-5). No difference in HBIR EE activity was observed between halothane and sevoflurane, which agrees with findings in adults (21). Although infants were premedicated with atropine, an agent known to decrease vagal activity, the oral dose of 20 µg/kg is minimal compared with the intravenous dose required for ablation of a vagal response in dogs (1.5 mg/kg) (34).…”

“…The HBIR persists beyond the newborn period (36,44) and remains active even at 1 yr of age (37), although longitudinal measurements show a reduction in activity from 90% in early infancy (36,44) to 50% at 1 yr of age (37). Unlike in anesthetized adults, in whom there is no response (21), end-expiratory airway occlusion (EEO) during tidal breathing, a maneuver that removes the inspiratory-inhibitory effect of lung inflation, results in a prolongation of inspiration by ϳ20% in anesthetized infants (3).…”

Effects of Halothane, Enflurane, Isoflurane, and Sevoflurane on Slowly Adapting Pulmonary Stretch Receptor Activity in Anesthetized Dogs

“…Clark and Euler [4] suggested that the difference of respiratory timing among inhalation anesthetics may depend on the degree of strength of the Hering-Breuer inflation reflex by those drugs. Several studies have reported the ventilatory effects of inhalation anesthetics from the aspect of reflex actions [3,7,9,10]; however, only a few studies have been performed as to the effects of recent available inhalation anesthetics on vagal inputs originating from SARs.…”

Respiratory Mechanics During Sevoflurane Anesthesia in Children With and Without Asthma

“…Increasing the concentration of sevoflurane was followed by a similar decrease in Rrs in both groups. There was also a reduction in tidal volume with increased sevoflurane, which may be related to a great depression of intercostal muscle function with increasing depth of anesthesia (20). There was a significant tachypnea in both groups, which has recently been reported after induction of sevoflurane in adults (21).…”