Maintaining the airway. Was Guedel wrong?

Malfunctioning unidirectional valves of Ohmeda Series 5 and 5A carbon dioxide absorbers

“…Lee and Kwon on their excellent case presentation of "Shivering following retrobulbar block'. 1 We are pleased to see that Ihey support our hypothesis regarding the mechanism by which the central nervous system complications after retrobulbar block occur. 2 However, in our experience shivering is not only a warning sign, it is indeed one of the protean manifestations of brainstem anaesthesia.…”