Failure to account for practice effects leads to clinical misinterpretation of cognitive outcome following carotid endarterectomy.

Carotid endarterectomy (CEA) is a surgical procedure to remove stenotic atherosclerotic plaque from the origin of the carotid artery to reduce the risk of major stroke. Its impact on postoperative cognitive function (POCF) remains controversial; complicated, in part, by a traditional failure to account for practice effects incurred during consecutive psychometric testing. To address this for the first time, we performed psychometric testing (learning and memory, working memory, attention and information processing, and visuomotor coordination) in 15 male patients aged 68 ± 8 years with symptomatic carotid stenosis the day before and 24 h following elective CEA (two consecutive tests, 48 h apart). Multiple baselining was also performed in a separate cohort of 13 educationally, anthropometrically and age-matched controls (63 ± 9 years) not undergoing revascularization at identical time points with additional measures performed over a further 96 h (four consecutive tests, each 48 h apart). A single consecutive test in the control group resulted in progressive improvements in learning and memory, working memory, and attention and information (P < 0.05 vs. Test 1), with three tests required before cognitive performance stabilized. Following correction for practice effects in the patient group, CEA was associated with a deterioration rather than an improvement in learning and memory as originally observed (P < 0.05). These findings highlight the potential for the clinical misinterpretation of POCF unless practice effects are taken into account and provide practical recommendations for implementation within the clinical setting.

Vascular surgery, ICU and HDU: a 14-year observational study.

INTRODUCTION: Over the course of the past decade, numerous changes have occurred in the management of patients undergoing vascular surgical operations. The introduction of high dependency units (HDUs) has meant that many patients previously requiring observation in intensive care units (ICUs) are now managed in this new environment. In addition, many vascular patients may now be suitable for management on a vascular ward immediately following their surgery. This study reports the chronological changes in resource utilisation of patients undergoing major vascular surgery in a district general hospital over a 14-year period. PATIENTS AND METHODS: Details of all patients admitted to either the ICU or HDU under the care of a single vascular surgeon during the period 1991-2004 were extracted from a prospectively maintained anaesthetic department database. Details of the age and gender of the patients were obtained together with source of admission, place of discharge and need for re-admission. Operative details for each patient were extracted from a prospectively maintained vascular surgery database including type of procedure undertaken and degree of urgency. RESULTS: During the 14-year period under study, there was a dramatic decrease in the use of ICU facilities for the management of vascular patients from 100% in 1991 to 36% in 2004. There was a corresponding increase in the use of HDU for major vascular cases during the same period from 0% to 66%. However, despite a significant increase in the total number of major vascular operations performed, from 67 in 1991 to 185 in 2004 as a result of sub-specialisation, overall use of all high-care facilities fell as the number of patients returned directly to the vascular ward increased from 34% in 1991 to 64% in 2004. The efficacy of the choice of management venue was confirmed by the observation that only 7.7% of those managed on ICU had been initially managed at a lower level of care. In addition, only 1.8% of patients managed on HDU had been admitted after initially being managed on the vascular ward. CONCLUSIONS: Sub-specialisation over the past decade has meant a significantly increased major vascular work-load. Since the introduction of the HDU, there has been a significant fall in the use of ICU facilities for routine cases. These changes in resource utilisation have significant implications in terms of budget allocation. It would appear that finances, in relation to vascular surgery, should be concentrated on expanding HDU facilities and ensuring vascular surgery expertise amongst ward nursing staff.