Marsupials have two uteri, each of which connect to a lateral vagina and which both use a third, middle "vagina" which functions as the birth canal. Marsupial embryos form a choriovitelline placenta (which can be thought of as something between a monotreme egg and a "true" placenta), in which the eggs yolk sac supplies a large part of the embryos nutrition but also attaches to the uterine wall and takes nutrients from the mothers bloodstream. However, bandicoots also have a rudimentary chorioallantoic placenta, similar to those of placental mammals. The fetus usually develops fully in placental mammals and only partially in marsupials including kangaroos and opossums. In marsupials the uterus forms as a duplex organ of two uteri. In monotremes (egg-laying mammals) such as the platypus, the uterus is duplex and rather than nurturing the embryo, secretes the shell around the egg. It is essentially identical with the shell gland of birds and reptiles, with which the uterus is homologous.In mammals, the four main forms of the uterus are: duplex, bipartite, bicornuate and simplex. Duplex
There are two wholly separate uteri, with one fallopian tube each. Found in marsupials (such as kangaroos, Tasmanian devils, opossums, etc. ), rodents (such as mice, rats, and guinea pigs), and lagomorpha (rabbits and hares). Bipartite
The two uteri are separate for most of their length, but share a single cervix. Found in ruminants (deer, moose, elk etc. ), hyraxes, cats, and horses. Bicornuate
The upper parts of the uterus remain separate, but the lower parts are fused into a single structure.
The time required to flush a machine varies for different machines and volatile anesthetics. This prevention technique was optimized to prepare older generation anesthesia machines. Modern anesthetic machines have more rubber and plastic components which provide a reservoir for volatile anesthetics, and should be flushed for 60 minutes.Charcoal filters can be used to prepare an anesthesia machine in less than 60 seconds for people at risk of malignant hyperthermia. These filters prevent residual anesthetic from triggering malignant hyperthermia for up to 12 hours, even at low fresh gas flows. Prior to placing the charcoal filters, the machine should be flushed with fresh gas flows greater than 10 L/min for 90 seconds. Treatment
The current treatment of choice is the intravenous administration of dantrolene, the only known antidote, discontinuation of triggering agents, and supportive therapy directed at correcting hyperthermia, acidosis, and organ dysfunction. Treatment must be instituted rapidly on clinical suspicion of the onset of malignant hyperthermia. Dantrolene
Dantrolene is a muscle relaxant that appears to work directly on the ryanodine receptor to prevent the release of calcium. After the widespread introduction of treatment with dantrolene, the mortality of malignant hyperthermia fell from 80% in the 1960s to less than 5%. Dantrolene remains the only drug known to be effective in the treatment of MH. The recommended dose of dantrolene is 2.5 mg/kg, repeated as necessary. It is recommended that each hospital keeps a minimum stock of 36 dantrolene vials (720 mg), sufficient for four doses in a 70-kg person.