Lars S. Rasmussen, MD, PhD, Department of Anaesthesia, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark.

Postoperative Cognitive Dysfunction (POCD) is a decline in cognitive function detected days or weeks after surgery. It is usually subtle and lasts for weeks or months. The impairment must be evidenced by neuropsychological testing that is, unfortunately, associated with many problems related to its administration, statistical analysis and the interpretation of the test results. Risk factors for POCD are increasing age and type of surgery, with a very high risk after cardiac surgery (incidence 30-70% one week after surgery) and a low risk after minor, non-cardiac procedures, especially if performed on an outpatient basis.
Key words: cognitive function, postoperative, anesthesia, neuropsychological testing.

Michael J. Borrie, BSc, MB, ChB, FRCPC, Chair, Division of Geriatric Medicine, University of Western Ontario, London, ON.

Acute urinary retention (AUR) occurs predominantly in men and the incidence increases with age. The most common cause of urinary retention is benign prostatic hypertrophy (BPH). For men in their 40s who have no or mild obstructive symptoms (American Urologic Association Symptom Score 7 or less), the incidence of acute urinary retention is 2.6/1000 person years and 3.0/1000 person years in people with moderate to severe symptoms. In contrast, men in their 70's with mild to moderate symptoms have an incidence of AUR of 9.3/1000 person years and this rises to 34.7/1000 person years in those with moderate to severe symptoms.¹ Over five years, the risk of AUR for men in their 70s is 10% and for men in their 80s it is almost 30%.¹ These findings are based on a cohort of over 2,000 men 40-79, followed over four years and is one of the few longitudinal epidemiologic studies in the area.

Definition
Acute urinary retention has been defined as painful inability to void with a urine volume on catheterization of less than 800 ml.^2,3 Chronic retention has been defined as the presence of the post-void residual urine volume greater than 500 mls (estimated on bladder ultrasound scan) with or without upper tract dilatation on ultrasound and/or uremia occurring in a patient who is still able to void spontaneously.

D'Arcy Little, MD, CCFP
Director of Medical Education,
York Community Services, Toronto, ON.

Introduction
The nurses inform you that the elderly woman in Bed 140-B is agitated, and is complaining that a ghost-like man has been frightening her in her room at night. She is recovering from hip surgery that took place the day before yesterday. When you examine her in the morning, she is drowsy. Later that afternoon she is awake but has difficulty attending to your questions. You begin a work-up for postoperative delirium.

At one time or another, all physicians have faced the challenge of treating a delirious elderly patient in hospital. Delirium is a common, serious, yet potentially preventable cause of morbidity and mortality that primarily affects the elderly and is very common in the elderly post-surgical patient.^1-3 The condition is characterized by a disturbance of consciousness and a change in cognition that develops over a short period of time and tends to have a fluctuating course over the day. It is caused by the direct physiological consequences of a general medical condition (See Table 1).^2,4 The following article will review the epidemiology and etiology of delirium with a view to presenting an approach to the prevention of postoperative delirium in the elderly surgical patient.