Differential Age Effects of Mean Arterial Pressure and Rewarming on Cognitive Dysfunction After Cardiac Surgery

Abstract

Central nervous system dysfunction is a common consequence of otherwise uncomplicated cardiac surgery. Many mechanisms have been postulated for the cognitive dysfunction that is part of these neurologic sequelae. The purpose of our investigation was to evaluate the effects of mean arterial pressure (MAP) during cardiopulmonary bypass (CPB) and the rate of rewarming on cognitive decline after cardiac surgery. Two hundred thirty-seven patients completed preoperative and predischarge neuropsychologic testing. MAP and temperature were recorded at 1-min intervals using an automated anesthesia record keeper. MAP area less than 50 mm Hg (time and degree of hypotension), as well as the maximal rewarming rate, were determined for each patient. Multivariable linear regression revealed that the rate of rewarming and MAP were unrelated to cognitive decline. However, interactions significantly associated with cognitive decline were found between age and MAP area less than 50 mm Hg on one measure, and between age and rewarming rate in another, identifying susceptibility of the elderly to these factors. Although MAP and rewarming were not the primary determinates of cognitive decline in this surgical population, hypotension and rapid rewarming contributed significantly to cognitive dysfunction in the elderly.

Jugular bulb oximetry during cardiac surgery

“…Therefore, the higher incidence of neuropsychological impairment in patients with marked S j o 2 desaturation during rewarming may have been caused by abnormalities in flow/metabolism coupling and/or brain pathology that were present before rewarming, rather than desaturation that occurs during rewarming per se. In addition, Newman et al [67] reported that the rewarming speed had no independent effect on postoperative neuropsychological outcome. Similarly, S j o 2 desaturation had only a minor independent effect on neuropsychological outcome when baseline neuropsychological status, educational level and age are considered.…”

Cerebral oxygenation is better during mild hypothermic than normothermic cardiopulmonary bypass

“…Recent reports from Duke University demonstrated that a reduction in SjvO 2 value had only a minor effect on neuropsychologic outcome. 15 However, Goto et alreported that a reduction in SjvO 2 in patients with preexisting neurological disorder may have great influence on neurologic outcome. 16 We did not examine neurological outcome in patients treated by normothermic CPB.…”

Haemodilution tolerance in patients with mitral regurgitation

“…min ¹1 ) infusions [5,6]. After tracheal intubation a triple-lumen central venous catheter and a pulmonary artery catheter were inserted via the right internal jugular vein.…”