Cognitive dysfunction 1-2 years after non-cardiac surgery in the elderly. ISPOCD group. International Study of Post-Operative Cognitive Dysfunction.

BACKGROUND: Postoperative cognitive dysfunction (POCD) is a well-recognised complication of cardiac surgery, but evidence of POCD after general surgery has been lacking. We recently showed that POCD was present in 9.9% of elderly patients 3 months after major non-cardiac surgery. The aim of the present study was to investigate whether POCD persists for 1-2 years after operation. METHODS: A total of 336 elderly patients (median age 69 years, range 60-86) was studied after major surgery under general anesthesia. Psychometric testing was performed before surgery and at a median of 7, 98 and 532 days postoperatively using a neuropsychological test battery with 7 subtests. A control group of 47 non-hospitalised volunteers of similar age were tested with the test battery at the same intervals. RESULTS: 1-2 years after surgery, 35 out of 336 patients (10.4%, CI: 7.2-13.7%) had cognitive dysfunction. Three patients had POCD at all three postoperative test sessions (0.9%). From our definition of POCD, there is only a 1:64000 likelihood that a single subject would have POCD at all three test points by chance. Logistic regression analysis identified age, early POCD, and infection within the first three postoperative months as significant risk factors for long-term cognitive dysfunction. Five of 47 normal controls fulfilled the criteria for cognitive dysfunction 1-2 years after initial testing (10.6%, CI: 1.8-19.4%), i.e. a similar incidence of age-related cognitive impairment as among patients. CONCLUSION: POCD is a reversible condition in the majority of cases but may persist in approximately 1% of patients.

Do blood concentrations of neurone specific enolase and S-100 beta protein reflect cognitive dysfunction after abdominal surgery?ISPOCD Group.

Neurone specific enolase (NSE) and S-100 beta protein have been used as markers of brain damage. We hypothesized that blood concentrations of NSE and S-100 beta protein reflect cognitive dysfunction after abdominal surgery. We studied 65 elderly patients in whom neuropsychological testing was performed before abdominal surgery, at discharge from hospital and after 3 months. Serum concentrations of NSE and S-100 beta protein were measured before surgery and after 24, 48 and 72 h. Serum concentrations of S-100 beta protein increased significantly while NSE concentrations decreased significantly. The increase in S-100 beta protein concentration after 48 h was significantly greater in patients with delirium. No correlation was found between cognitive dysfunction and S-100 beta protein or NSE concentration. We conclude that blood concentrations of S-100 beta protein increase after abdominal surgery and may be related to postoperative delirium.

Changes in plasma potassium concentration during carbon dioxide pneumoperitoneum.

Hyperkalaemia with ECG changes had been noted during prolonged carbon dioxide pneumoperitoneum in pigs. We have compared plasma potassium concentrations during surgery in 11 patients allocated randomly to undergo either laparoscopic or open appendectomy and in another 17 patients allocated randomly to either carbon dioxide pneumoperitoneum or abdominal wall lifting for laparoscopic colectomy. Despite an increasing metabolic acidosis, prolonged carbon dioxide pneumoperitoneum resulted in only a slight increase in plasma potassium concentrations, which was both statistically and clinically insignificant. Thus hyperkalaemia is unlikely to develop in patients with normal renal function undergoing carbon dioxide pneumoperitoneum for laparoscopic surgery.

Benzodiazepines and postoperative cognitive dysfunction in the elderly. ISPOCD Group. International Study of Postoperative Cognitive Dysfunction.

Postoperative cognitive dysfunction (POCD) has been attributed to long-acting sedatives. We hypothesized that diazepam and its active metabolites could be detected in blood after surgery and correlated with POCD, 1 week after surgery in elderly patients. We studied 35 patients, 60 yr or older, undergoing abdominal surgery with general anaesthesia, including diazepam. Neuropsychological tests were performed before surgery and at discharge, where blood concentrations (free fraction) of benzodiazepines were also measured. POCD was found in 17 patients (48.6%). Diazepam or desmethyldiazepam was detected in 34 patients; median postoperative blood concentrations were 0.06 and 0.10 mumol kg-1, respectively. In a multiple regression analysis considering age, duration of anaesthesia and blood concentrations of diazepam and desmethyldiazepam, only age was found to correlate with the composite z-score (F test, P < 0.01). The postoperative cognitive dysfunction we found in elderly patients after operation could not be explained by benzodiazepine concentrations detected in blood.

Long-term postoperative cognitive dysfunction in the elderly ISPOCD1 study. ISPOCD investigators. International Study of Post-Operative Cognitive Dysfunction.

BACKGROUND: Long-term postoperative cognitive dysfunction may occur in the elderly. Age may be a risk factor and hypoxaemia and arterial hypotension causative factors. We investigated these hypotheses in an international multicentre study. METHODS: 1218 patients aged at least 60 years completed neuropsychological tests before and 1 week and 3 months after major non-cardiac surgery. We measured oxygen saturation by continuous pulse oximetry before surgery and throughout the day of and the first 3 nights after surgery. We recorded blood pressure every 3 min by oscillometry during the operation and every 15-30 min for the rest of that day and night. We identified postoperative cognitive dysfunction with neuropsychological tests compared with controls recruited from the UK (n=176) and the same countries as study centres (n=145). FINDINGS: Postoperative cognitive dysfunction was present in 266 (25.8% [95% CI 23.1-28.5]) of patients 1 week after surgery and in 94 (9.9% [8.1-12.0]) 3 months after surgery, compared with 3.4% and 2.8%, respectively, of UK controls (p<0.0001 and p=0.0037, respectively). Increasing age and duration of anaesthesia, little education, a second operation, postoperative infections, and respiratory complications were risk factors for early postoperative cognitive dysfunction, but only age was a risk factor for late postoperative cognitive dysfunction. Hypoxaemia and hypotension were not significant risk factors at any time. INTERPRETATION: Our findings have implications for studies of the causes of cognitive decline and, in clinical practice, for the information given to patients before surgery.

Adverse events with continuous doxapram infusion against late postoperative hypoxaemia.

OBJECTIVE: A randomized double-blind controlled trial of doxapram versus placebo against late postoperative hypoxaemia was planned to include 40 patients (2 x 20). RESULTS: After inclusion of 18 patients a serious adverse event was encountered with development of a brain stem infarction in a 90-year-old woman receiving doxapram. At this point the randomization code was broken and we decided to terminate the trial. Three of nine patients receiving doxapram had had an adverse event whereas none of the patients receiving placebo had adverse events (P = 0.2). In the 18 patients studied, there was an insignificant trend towards higher mean oxygen saturation in the doxapram group, and a significantly higher minimum oxygen saturation and reduced number of hypoxaemic events on the first postoperative night. CONCLUSION: Although these preliminary data on the effect of doxapram on postoperative hypoxaemia seem promising, further studies on the effect of continuous nocturnal postoperative doxapram infusion on levels of arterial oxygen saturation should be postponed until more knowledge about the pharmacokinetics of doxapram in this particular clinical situation has been gathered.