Negative arterial to end-tidal carbon dioxide gradient: an additional sign of malignant hyperthermia during desflurane anesthesia.

Widespread use of desflurane anesthesia has changed the clinical presentation of malignant hyperthermia (MH). Delayed onset of MH symptoms has been reported previously. A negative gradient between arterial to end-tidal CO2 ([a-ET]Pco2) was observed during anesthesia in pregnant patients and infants and has been associated with increased CO2 production, increased cardiac output, reduced functional residual capacity, and low lung compliance. The same conditions exist in cases of MH crisis. We describe an unusual case of MH in which a negative value of (a-ET) Pco2 gradient has been used as diagnostic and monitoring tool.