[An activated charcoal filter for eliminating volatile anesthetics. A contribution to the management of malignant...

Anesthesia machines may not be contaminated with anesthetic vapors when a patient susceptible to malignant hyperthermia (MHS) is to be anesthetized. A clean machine may not always be available, and recommended protocols for preparing a contaminated machine are cumbersome and time-consuming. We suggest the use of an activated charcoal filter that is easily assembled from spare parts available in many anesthesiology departments (Fig. 2). It consists of an HME container (Servo-Humidifier 150, Siemens-Elema), a sieve set from an anesthesia circuit (7a/8-ISO, Dräger, Lübeck), and grained activated charcoal (2.5 mm, Merck, Darmstadt). All parts are autoclavable. The filter adsorbs anesthetic vapors quantitatively (Fig. 3) without affecting humidity, nitrous oxide concentration, or circuit resistance. Storage of such a filter may obviate the need to keep a clean anesthesia machine available for MHS patients.