Use of a maze to detect cognitive dysfunction in a porcine model of hypothermic circulatory arrest.
BACKGROUND
Hypothermic circulatory arrest (HCA) can result in cognitive impairment not reflected by histopathology or gross neurologic observation. We tested the sensitivity of two multi-room maze tasks in detecting cerebral dysfunction after HCA in pigs.


METHODS
Twenty-seven pigs were studied, divided between two tasks. 13 underwent 90 minutes HCA at 20 degrees C and were trained from postoperative day (POD) 7; 14 were unoperated controls. The maze includes a holding area, 8 rooms, and a center hallway. One piece of apple is placed in each baited room on each of 10 days of learning evaluation. After a pig enters a room, doors to all other rooms close, and the pig must return to the holding area. In task 1, 6 of 8 rooms were baited, and each day's session ended when each baited room had been entered, or after 20 trials. In task 2, initially only the right- or left-sided rooms were baited. Pigs were evaluated each day until they entered 4 baited rooms, or for 15 trials; the process was then repeated, baiting the other side.


RESULTS
Intraoperative physiology and postoperative recovery showed no differences between task 1 or 2 pigs. Task 1 did not distinguish between control and HCA groups (p = 0.5), but task 2 revealed significantly (p = 0.04) better learning in controls.


CONCLUSIONS
The significantly poorer performance of pigs after HCA suggests that the reversal of baited rooms in task 2 provides the sensitivity to detect cognitive dysfunction. The maze is a promising tool to investigate in pigs the mild cerebral damage often seen after HCA.
Hagl
Christian
C
Department of Cardiothoracic Surgery, Mount Sinai School of Medicine, New York, New York 10029, USA.
Weisz
Donald J
DJ
Khaladj
Nawid
N
Griepp
Matthew M
MM
Spielvogel
David
D
Yang
Bo-Yi
BY
de Asla
Richard A
RA
Bodian
Carol A
CA
Griepp
Randall B
RB
D000818:Animals; D002315:Cardiopulmonary Bypass; D003072:Cognition Disorders / Q000175:diagnosis*; D004195:Disease Models, Animal; D006324:Heart Arrest, Induced / Q000009:adverse effects*; D018782:Maze Learning; D013552:Swine