Prolonged sevoflurane inhalation was not nephrotoxic in two patients with refractory status asthmaticus

Comparison of recovery in pediatric patients: a retrospective study

OBJECTIVE

The recovery after general anesthesia is influenced by the choice of inhalational agent. Stimulations might make patient's agitate. However, the recovery using no touch technique might be safer. In this study, we compared the recovery time, awakening end-tidal concentration, and respiratory complications among inhalational anesthetics in pediatric patients using no touch technique, retrospectively.

MATERIAL AND METHODS

The subjects were pediatric patients aged 3 months to 11 years under general anesthesia using sevoflurane, isoflurane, or desflurane. Background, awakening end-tidal concentration, respiratory complications, the time of eye open, body movement, and extubation were recorded.

RESULTS

A total of 170 patients were included in the study. There were no respiratory complications during emergence. Awakening end-tidal concentration in desflurane was 0.98%, sevoflurane (0.39%), and isoflurane (0.25%). In patients received desflurane, the time of body movement, eye open, and extubation were significantly shorter than patients who received other anesthetics (p < 0.05).

CONCLUSIONS

The recovery from desflurane was significantly shorter among three inhalational anesthetics with no touch technique. In addition, no airway-related complication occurred.

CLINICAL RELEVANCE

The recovery from desflurane might be useful to predict emergence by end-tidal inhalational concentration.

Targeted Versus Continuous Delivery of Volatile Anesthetics During Cholinergic Bronchoconstriction

Volatile anesthetics have been shown to reduce lung resistance through dilation of constricted airways. In this study, we hypothesized that that diffusion of inhaled anesthetics from airway lumen to smooth muscle would yield significant bronchodilation in vivo, and systemic recirculation would not be necessary to reduce lung resistance (RL ) and elastance (EL ) during sustained bronchoconstriction. To test this hypothesis, we designed a delivery system for precise timing of inhaled volatile anesthetics during the course of a positive pressure breath. We compared changes in RL , EL , and anatomic dead space (VD ) in canines (N=5) during pharmacologically-induced bronchoconstriction with intravenous methacholine, and following treatments with: 1) targeted anesthetic delivery to VD ; and 2) continuous anesthetic delivery throughout inspiration. Both sevoflurane and isoflurane were used during each delivery regimen. Compared to continuous delivery, targeted delivery resulted in significantly lower doses of delivered anesthetic and decreased end-expiratory concentrations. However, we did not detect significant reductions in RL or EL for either anesthetic delivery regimen. This lack of response may have resulted from an insufficient dose of the anesthetic to cause bronchodilation, or from the preferential distribution of air flow with inhaled anesthetic delivery to less constricted, unobstructed regions of the lung, thereby enhancing airway heterogeneity and increasing apparent RL and EL .

Toxicity of inhaled agents after prolonged administration

Inhaled anesthetics have been utilized mostly for general anesthesia in the operating room and oftentimes for sedation and for treatment of refractory status epilepticus and status asthmaticus in the intensive care unit. These contexts in the ICU setting are related to potential for prolonged administration wherein potential organ toxicity is a concern. Over the last decade, several clinical and animal studies of neurotoxicity attributable to inhaled anesthetics have been emerging, particularly in extremes of age. This review overviews potential for and potential mechanisms of neurotoxicity and systemic toxicity of prolonged inhaled anesthesia and clinical scenarios where inhaled anesthesia has been used in order to assess safety of possible prolonged use for sedation. High dose inhaled agents are associated with postoperative cognitive dysfunction (POCD) and other situations. However, thus far no strong indication of problematic neuro or organ toxicity has been demonstrated after prolonged use of low dose volatile anesthesia.

Volatile Anesthetics and the Treatment of Severe Bronchospasm: A Concept of Targeted Delivery

Status asthmaticus (SA) is a severe, refractory form of asthma that can result in rapid respiratory deterioration and death. Treatment of SA with inhaled anesthetics is a potentially life-saving therapy, but remarkably few data are available about its mechanism of action or optimal administration. In this paper, we will review the clinical use of inhaled anesthetics for treatment of SA, the potential mechanisms by which they dilate constricted airways, and the side effects associated with their administration. We will also introduce the concept of 'targeted' delivery of these agents to the conducting airways, a process which may maximize their therapeutic effects while minimizing associated systemic side effects. Such a delivery regimen has the potential to define a rapidly translatable treatment paradigm for this life-threatening disorder.