Bispectral index analysis during cardiac arrest and cardiopulmonary resuscitation in a propofol-anesthetized calf

To describe bispectral index (BIS) findings and compare them with cardiovascular and respiratory trends during cardiac arrest and successful CPR in a propofol-anesthetized calf.

A 3-month-old calf was anesthetized as part of a research project. A thromboxane analog drug (U46619) was administered IV to induce pulmonary hypertension. Within 10 minutes following U46619 administration, cardiac activity deteriorated, leading to asystole. At this point, BIS and suppression rate were 0 and 100, respectively. Anesthetic drug delivery was discontinued and external chest compressions were initiated. During CPR, end-tidal CO2 concentration decreased and BIS increased, but no spontaneous cardiac activity was noted, thus IV epinephrine was administered. Return of spontaneous circulation was achieved and systemic arterial hypertension developed, while BIS briefly decreased and then increased during the following 2 minutes. The calf's cardiopulmonary variables returned to physiological ranges within 10 minutes after the return of spontaneous circulation and remained stable.

This is the first report in which BIS is documented together with standard monitoring techniques during cardiopulmonary arrest and resuscitation in a calf. BIS varied with cardiovascular performance, and may be indicative of cerebral blood flow in this context. Further research may be warranted to define the role of BIS for monitoring cerebral activity during CPR.