Article

Accelerating the washout of inhalational anesthetics from the Dräger Primus anesthetic workstation: effect of exchangeable internal components.

Department of Anesthesia, The Hospital for ick Children, University of Toronto, Canada.
Anesthesiology (Impact Factor: 6.17). 02/2007; 106(2):289-94.
Source: PubMed

ABSTRACT To establish guidelines for the preparation of the Primus anesthetic workstation (Dräger, Lübeck, Germany) for malignant hyperthermia-susceptible patients, the authors evaluated the effect of replacing the workstation's exchangeable internal components on the washout of isoflurane.
Primus workstations were exposed to isoflurane, and contaminated internal components were replaced as follows: group 1, no replacement; group 2, new ventilator diaphragm; group 3, autoclaved ventilator diaphragm; group 4, autoclaved integrated breathing system; group 5, flushed integrated breathing system; group 6, autoclaved ventilator diaphragm and integrated breathing system. The fresh gas flow was set at 10 l/min, and subsequently reduced to 3 l/min when a concentration of 5 ppm was achieved. Isoflurane concentration was measured in the inspiratory limb of the circle circuit every minute.
Washout times for isoflurane decreased in the following order: group 1 (67 +/- 6.5 min) > groups 2 and 3 (50 +/- 4.1 and 50 +/- 5.7 min, respectively) > group 5 (43 +/- 9.5 min) > group 4 (12 +/- 1.5 min) > group 6 (3.2 +/- 0.4 min). Isoflurane concentration increased approximately threefold when the fresh gas flow was reduced to 3 l/min.
Washout of isoflurane increased 20-fold with the use of an autoclaved ventilator diaphragm and integrated breathing system. To prepare the Primus for malignant hyperthermia-susceptible patients, the authors recommend replacing the ventilator diaphragm and integrated breathing system with autoclaved components, flushing the workstation for 5 min at a fresh gas flow of 10 l/min, and maintaining this flow for the duration of anesthesia.

0 Followers
 · 
89 Views
  • [Show abstract] [Hide abstract]
    ABSTRACT: Malignant hyperthermia is a potentially lethal inherited disorder characterized by disturbance of calcium homeostasis in skeletal muscle. Volatile anesthetics and/or the depolarizing muscle relaxant succinylcholine may induce this hypermetabolic muscular syndrome due to uncontrolled sarcoplasmic calcium release via functionally altered calcium release receptors, resulting in hypoxemia, hypercapnia, tachycardia, muscular rigidity, acidosis, hyperkalemia, and hyperthermia in susceptible individuals. Since the clinical presentation of malignant hyperthermia is highly variable, survival of affected patients depends largely on early recognition of the symptoms characteristic of malignant hyperthermia, and immediate action on the part of the attending anesthesiologist. Clinical symptoms of malignant hyperthermia, diagnostic criteria, and current therapeutic guidelines, as well as adequate management of anesthesia in patients susceptible to malignant hyperthermia, are discussed in this review.
    Therapeutics and Clinical Risk Management 05/2014; 10:355-362. DOI:10.2147/TCRM.S47632 · 1.34 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: If a malignant hyperthermia-susceptible patient is to receive an anesthetic, an anesthesia machine that has been used previously to deliver volatile anesthetics should be flushed with a high fresh gas flow. Conflicting results from previous studies recommend flush times that vary from 10 to 104 minutes. In a previously proposed alternative decontamination technique, other investigators placed an activated charcoal filter in the inspired limb of the breathing circuit. We placed activated charcoal filters on both the inspired and expired limbs of several contaminated anesthesia machines and measured the time needed to flush the machine so that the delivered concentrations of isoflurane, sevoflurane, and desflurane would be <5 parts per million (ppm). We next simulated the case for which malignant hyperthermia is diagnosed 90 minutes after induction of anesthesia and measured how well activated charcoal filters limit further exposure. Activated charcoal filters decrease the concentration of volatile anesthetic delivered by a contaminated machine to an acceptable level in <2 minutes. The concentrations remained well below 5 ppm for at least 60 minutes. When malignant hyperthermia is diagnosed after induction of anesthesia, we found that with charcoal filters in place, the current anesthesia machine may be used for at least 67 minutes before the inspired concentration exceeds 5 ppm. Activated charcoal filters provide an alternative approach to the 10 to 104 minutes of flushing that are normally required to prepare a machine that has been used previously to deliver a volatile anesthetic.
    Anesthesia and analgesia 06/2011; 112(6):1363-70. DOI:10.1213/ANE.0b013e318213fad7 · 3.42 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Preoperative flushing of an anesthesia workstation is an alternative for preparation of the anesthesia workstation before use in malignant hyperthermia-susceptible patients (MHS). We studied in vitro, using a test lung, the washout profile of sevoflurane in 7 recent workstations during adult and, for the first time, pediatric ventilation patterns. Anesthesia workstations were first primed with 3% sevoflurane for 2 hours and then prepared according to the recommendations of the Malignant Hyperthermia Association of the United States. The flush was done with maximal fresh gas flow (FGF) with a minute ventilation equal to 600 mL × 15, to reach a sevoflurane concentration of <5 parts per million. After flush, 2 clinical situations were simulated in vitro to test the efficiency of preparation: decrease of FGF from max to 10 L/min, or decrease of minute ventilation to 50 mL × 30, to simulate the ventilation of an MHS infant. We report washout delays for MHS patients for previously studied workstations (Primus®, Avance®, and Zeus®) and more interestingly, for machines not previously tested (Felix®, Flow-I®, Perseus®, and Leon®). An increase of sevoflurane concentration was observed when decreasing FGF (except for flow-I® and Leon®) and during simulation of MHS infant ventilation (except for Felix®). This descriptive study strongly suggests that washout profiles may differ for each anesthesia workstation. We advise the use of maximal FGF during preparation and anesthesia. Required flushing times are longer when preparing an anesthesia workstation before providing anesthesia for MHS infants.
    Anesthesia and analgesia 05/2014; 119(1). DOI:10.1213/ANE.0000000000000208 · 3.42 Impact Factor