The screening of atracurium in MHS swine

Dose-response relationship of atracurium besylate in the halothane-anaesthetised pig

The dose response relationship for the intermediate-acting non-depolarising muscle relaxant, atracurium besylate in the pig was determined using evoked electromyography. An incremental dose technique was used in seven Large White/Landrace crossbred pigs anaesthetised with nitrous oxide and halothane. ED50 and ED95 were 510 +/- 87 micrograms kg-1 and 1150 +/- 270 micrograms kg-1, respectively. Although these values may represent an overestimate, they provide a reasonable guideline for the use of atracurium by veterinary anaesthetists.

[Management of a patient with malignant hyperthermia susceptibility during anesthesia and daily living]

Death from malignant hyperthermia (MH) still occurs in France. However, anaesthesia of the MH susceptible (MhS) patient is quite possible without any more risk than for patients who are not MhS. Guidelines have been worked out: "trigger" drugs such as volatile anaesthetics (halothane, enflurane, isoflurane) and depolarizing muscle relaxants must be imperatively avoided; "non-trigger" drugs should be used, such as nitrous oxide, barbiturates, benzodiazepines, propofol, opiates, non-depolarizing muscle relaxants, amide or ester local anaesthetics at the usual doses without adrenaline. Moreover, dantrolene should be available in all hospitals, 12 bottles being a minimum at hand, or, better, 30 (about 10 mg.kg-1). In some cases, such as emergencies, an unprepared operating theatre, or an unprepared ventilator, the patient should be premedicated with 2.5 mg.kg-1 dantrolene intravenously. The ventilator, the circuit and the operating theatre should not contain any trace of halogenated vapour. The usual parameters, as well as temperature and expired CO2 concentration, should be closely monitored. MhS patients must also be given counselling. This includes explanations about MH, its genetic features, the main laboratory tests used to detect susceptibility, as well as advice about lifestyle, the use of drugs other than general and local anaesthetics, and a discussion concerning the association of MH with other diseases. This counselling is not always easy to provide, because many answers are not, as yet, definitive.

Atypical malignant hyperthermia with persistent hyperkalaemia during renal transplantation

A 35-year-old 110 kg male developed marked hyperkalaemia, hyponatraemia, hypercapnia and hyperthermia during living-related renal transplantation under anaesthesia with oxygen-nitrous oxide, isoflurane and muscle relaxation with atracurium. This is the first report of successfully treated malignant hyperthermia triggered by isoflurane during renal transplantation with early appearance and persistent (to 12 hours after surgery) electrolyte abnormalities.