After teaching a class about agents commonly associated with the development of malignant hyperthermia, the instructor determines that additional teaching is needed when the students identify which drug as a possible cause?

Morphine

Explanation:

Malignant hyperthermia is a syndrome that manifests during general anesthesia, however morphine is not associated with malignant hyperthermia. Among the main characteristics are the rise in body temperature, hence the name, accompanied by the exhalation of carbon dioxide, muscle stiffness and increased heart rate.

Symptoms may also occur post-anesthetically, which is rarer. Usually, the suspicion of malignant hyperthermia occurs when the person under anesthesia is under adequate mechanical ventilation and yet has increased carbon dioxide and tachycardia. The clinical picture is considered serious, since there is the possibility of evolution to an irreversible shock, which may even lead to death (hence the malignant term) if not diagnosed and, if necessary, taken the appropriate measures.

the drugs can be any of the following-potent volatile anesthetic gases such as halothane, sevoflurane, desflurane and the depolarizing muscle relaxant succinylcholine

Explanation:

The incidence of MH episodes during anesthesia is between 1:5,000 and 1:50,000–100,000 anesthesias. Even though a MH crisis may develop at first exposure to anesthesia with those agents known to trigger an MH episode, on average, patients require three anesthesias before triggering. Reactions develop more frequently in males than females (2:1). All ethnic groups are affected, in all parts of the world. The highest incidence is in young people, with a mean age of all reactions of 18.3 years. It has been found that children under 15 years age comprised 52.1% of all reactions. Although described in the newborn, the earliest reaction confirmed by testing is six months of age [2]. The oldest is 78 years.

Genetically, MH is an autosomal dominant condition; the estimated prevalence of the genetic abnormalities may be as great as one in 3,000 individuals (range 1:3,000 to 1:8,500).

Numerous factors could be involved in triggering MH – age, type of anesthetic, environmental temperature, mitigating drugs administered simultaneously, and degree of stress [3]. Mauritz et al. [4] found an incidence of 1:37,500 in patients who had been diagnostically tested, which was similar to the incidence estimated by Robinson et al. (1:30,000) [5], although wide variability has been reported. A recent report suggested that the MH susceptible (MHS) trait may be present in 1:2,000–3,000 of the French population [6]. Bachand and colleagues examined the incidence of MH in Quebec, Canada, where many families had been biopsied [7]. They traced the pedigrees of the patients to the original immigrants from France and found an incidence of MH susceptibility of 0.2% in this province. However, that represented only five extended families.