I also read this interesting set of case reports and have two comments:

1) Among the most commonly used drug classes in anesthesia, neuromuscular blocking agents have the highest reported incidence of anaphylactoid/anaphylactic reactions. (Not antibiotics as many believe.)

2) i recall that both of the patients in this report were taking spironolactone, a potassium-sparing diuretic. The authors do not report their pre-op K+ levels. Could the slight increase in K+ (0.5 to 1.0 mEq/L) associated with SCh have partially contributed to these events? . . . hyperkalemic cardiac arrest?