2019 Volume 46 Issue 2 Pages 131-138
[Background] Various causes of postoperative cognitive dysfunction (POCD) following cardiac surgery have been speculated, including a previous report that found use of a heart-lung machine to be a causative factor.
[Methods] We investigated 160 consecutive patients who underwent a heart valve operation with a cardiopulmonary bypass, and received 4 different types of pre- and postoperative recognition function tests. Those who showed a greater than 20% reduction in postoperative test values or experienced difficulty with the assessments following surgery were judged to be POCD. Factors related to POCD occurrence were then evaluated using multivariate analysis.
[Results] POCD occurred in 49 cases (30.6%). Comparisons between the onset and non-onset groups revealed that patients with onset were significantly older, while many of those had a medical history of cognitive impairment and blood symptoms, as well as higher HbA1c values. The onset group also had a significantly shorter rewarming time during cardiopulmonary bypass, and significantly lower perfusion index (PI), hemoglobin, and oxygen delivery (DO2i) values during rewarming. During the postoperative course, the onset group had a significantly higher creatinine value, greater rate of increase in postoperative serum creatinine, longer intubation time, and longer length of ICU or hospital stay. Multivariate analysis showed age (cut-off value 72 years, AUC 0.71, OR 6.09, CI 2.40-15.5; P=0.0021) and DO2i during rewarming at 35°C (cut-off value 276mL/min/m2, AUC 0.79, OR 9.28, CI 4.22-20.4; P<0.0001) as independent risk factors for POCD occurrence.
[Discussion] POCD following cardiac surgery results not only in a decline of cognitive capacity, but also has a negative influence on the postoperative course. Notably, for effective cardiopulmonary bypass management in elderly patients, maintaining an adequate DO2i value during rewarming is important.
[Conclusion] Both age and DO2i during the rewarming period following a cardiopulmonary bypass were found to be factors related to POCD occurrence in cardiac surgery patients.
