Cerebral injury during cardiopulmonary bypass: emboli impair memory.

Full Abstract

OBJECTIVES: Cognitive deficits occur in up to 80% of patients after cardiac surgery. We investigated the influence of cerebral perfusion and embolization during cardiopulmonary bypass on cognitive function and recovery. METHODS: Cerebrovascular reactivity was measured in 70 patients before coronary operations in which nonpulsatile bypass was used. Throughout the operations, middle cerebral artery flow velocity and embolization were recorded by transcranial Doppler and regional oxygen saturation was recorded by near-infrared spectroscopy. Cognitive function was measured by a computerized battery of tests before the operation and 1 week, 2 months, and 6 months after surgery. Elderly patients undergoing urologic surgery served as controls. RESULTS: Cerebrovascular reactivity was impaired preoperatively in 49 patients. Median (interquartile range) regional cerebral oxygen saturation fell during bypass by 10% (6%-15%), indicating increased oxygen extraction, whereas mean middle cerebral flow velocity increased significantly by a median of 6 cm/s (both P <.0001, Wilcoxon), suggesting increased arterial tone. More than 200 emboli were detected in 40 patients, mainly on aortic clamping and release, when bypass was initiated, and during defibrillation. Cognitive function deteriorated more in patients having cardiopulmonary bypass than in control patients having urologic operations but recovered in most tests by 2 months. Measures of cerebral perfusion (poor cerebrovascular reactivity, low arterial pressures, and flow velocity in the middle cerebral artery) predicted poor attention at 1 week (r = 0.3, P <.01, Spearman). Emboli were associated with memory loss (r = 0.3, P <.02, Spearman). CONCLUSIONS: Cognitive deficits were common after cardiopulmonary bypass. Occult cerebrovascular disease was more severe than expected and predisposed to attention difficulties, whereas emboli caused memory deficits. We believe this to be the first report of differing cognitive effects from emboli and hypoperfusion.

Author information

Author/s: Fearn, S J (SJ); Pole, R (R); Wesnes, K (K); Faragher, E B (EB); Hooper, T L (TL); McCollum, C N (CN);

Affiliation: Department of Surgery, South Manchester University Hospitals, Nell Lane, West Didsbury, Manchester, M20 2LR, United Kingdom.

Journal and publication information

Publication Type: Clinical Trial; Comparative Study; Controlled Clinical Trial; Journal Article; Research Support, Non-U.S. Gov't

Journal: The Journal of thoracic and cardiovascular surgery (J Thorac Cardiovasc Surg), published in United States. (Language: eng)

Reference: 2001-Jun; vol 121 (issue 6) : pp 1150-60

Dates: Created 2001/05/31; Completed 2001/07/05; Revised 2006/11/15;

PMID: 11385383, status: MEDLINE (last retrieved date: 2/18/2009)

Sourced from the National Library of Medicine. Abstract text and other information may be subject to copyright.

External Links for this article
(including full text providers, if available):

Click Electronic Full-text Provider Links to see options for finding the electronic full text links to this article. Note there may be a subscription or fee required for access to the full text. See our FAQ for information on finding FREE full text articles.

This article may also be located in paper journal collections available in many libraries. Use the Journal and Publication Information above to find the full article.