Postoperative cognitive dysfunction in middle-aged patients

BACKGROUND: Postoperative cognitive dysfunction (POCD) after noncardiac surgery is strongly associated with increasing age in elderly patients; middle-aged patients (aged 40-60 yr) may be expected to have a lower incidence, although subjective complaints are frequent. METHODS: The authors compared the changes in neuropsychological test results at 1 week and 3 months in patients aged 40-60 yr, using a battery of neuropsychological tests, with those of age-matched control subjects using Z-score analysis. They assessed risk factors and associations of POCD with measures of subjective cognitive function, depression, and activities of daily living. RESULTS: At 7 days, cognitive dysfunction as defined was present in 19.2% (confidence interval [CI], 15.7-23.1) of the patients and in 4.0% (CI, 1.6-8.0) of control subjects (P < 0.001). After 3 months, the incidence was 6.2% (CI, 4.1-8.9) in patients and 4.1% (CI, 1.7-8.4) in control subjects (not significant). POCD at 7 days was associated with supplementary epidural analgesia and reported avoidance of alcohol consumption. At 3 months, 29% of patients had subjective symptoms of POCD, and this finding was associated with depression. Early POCD was associated with reports of lower activity scores at 3 months. CONCLUSIONS: Postoperative cognitive dysfunction occurs frequently but resolves by 3 months after surgery. It may be associated with decreased activity during this period. Subjective report overestimates the incidence of POCD. Patients may be helped by recognition that the problem is genuine and reassured that it is likely to be transient.     

How to study postoperative nausea and vomiting

Anesthesiological journals are flooded by innumerable studies of postoperative nausea and vomiting (PONV). Nevertheless, PONV remains a continuing problem with an average incidence of 20-30%. This paper should provide essential information for the design, conduct, and presentation of these studies. It should also increase comparability among future studies and help clinicians in assessing and reading the literature on PONV. First, future studies should address new and relevant questions instead of repeatedly investigating prophylactically given antiemetics whose main results are predictable (e.g. already proven by meta-analysis). Second, group comparability should be based on well-proven risk factors and a simplified risk score for predicting PONV. Endless listings of doubtful risk factors should be avoided. Third, a realistic sample size estimation should be performed, i.e. in most cases at least 100 patients per group are necessary. Fourth, nausea, vomiting and rescue medication should be recorded and reported separately with the corresponding incidences (and number of patients with these separate symptoms), and the main end-point should be PONV. The entire observation period should cover 24 h. Additional reporting of the early (0-2 h) and delayed (2-24 h) postoperative period is desirable and should consider single and cumulative incidences. Lastly, interpretation of results should take into account the study hypothesis, sources of potential bias or imprecision, and the difficulties associated with multiplicity of analysis and outcomes.     

Increased Serum Concentrations of Lactic, Pyruvic and Uric Acid and Bilibubin After Postoperative Xylitol Infusion

Xylitol has been suggested as a more advantageous calory source for intravenous administration than glucose in certain clinical situation, but the general suitability of intravenous xylitol infusion has not been confirmed. Thirty-middle-aged women were infused with 100 g of xylitol as postoperative fluid therapy after gynaecological laparotomy and general anaesthesia. Another 10 women received 50 g of glucose in a similar manner and served as a reference group. Infusion of xylitol both at the rate of 0.25 g/kg/h (1000 ml 10% xylitol in approx. 8 h) and 0.5 g/kg/h (1000 ml 10% xylitol in approx. 4 h) caused a distinct increase in the serum concentrations of lactic acid, pyruvic acid, and uric acid; such an increase was not seen with glucose infusion. The faster infusion of xylitol also distinctly increased serum bilirubin concentrations. Because of the possibility of lactic acidosis and urate deposits in kidneys, infusion of 100 g or more of xylitol at a rate of 0.25 g/kg/h or faster is not safe for postoperative fluid therapy in routine clinical work.     

Factorial design provides evidence to guide practice of anaesthesia

Many scientific articles are written merely to get something published, neglecting the clinician who would like the medical literature to guide their practice. Evidence-based medicine is expected to help in clinical decision-making. Systematic reviews of the literature followed by a meta-analysis of randomized, controlled trials (RCT) have claimed to represent the highest strength of evidence. However, the results published in meta-analyses have not always been confirmed in subsequent large RCTs. An analysis of 12 large RCTs and 19 meta-analyses addressing the same questions found that the outcomes of these large RCTs were not predicted accurately 35% of the time by previously published meta-analyses. Therefore, meta-analyses of several small RCTs do not obviate the need for large, multicentre RCTs, which can still be considered as a gold standard for the development of clinical guidelines or practice plans. Moreover, large RCTs using a factorial design can be highly efficient because they can answer several clinical questions at the same time and offer the only systematic approach to investigate an interaction of combinations in multimodal approaches.     

Polyethylene Glycol as a Solvent for Diazepam: Bioavailability and Clinical Effects after Intramuscular Administration,Comparison of Oral,Intramuscular and Rectal Administration,and Precipitation from Intravenous Solutions

Abstract The bioavailability of diazepam (10 mg) was compared in a doubleblind cross–over manner in two studies on 15 healthy subjects. Serum diazepam levels were measured and the occurrence of pain at the injection site as well as fatigue was noted 20, 40, 60, 90 and 180 min. after the administration of 0.15 mg/kg of diazepam to seven subjects. Three intramuscular preparations were used: valium® (Roche), diapam® (Orion) and 301–K 2/74 (Orion). The last–mentioned preparation contained only half the propylene glycol contained in the other preparations, and polyethylene glycol (Macrogol) was the main solvent. The other eight subjects were similarly tested after the administration of diazepam orally, intramuscularly and rectally. In addition the precipitation of diazepam from intravenous solutions was investigated with diazepam in both solvents. Bioavailability and fatigue were similar after each treatment. 301–K 2/74 and its solvent placebo caused significantly less pain in the thigh than valium® or diapam®. The results suggest that an intramuscular injection of diazepam, deep into vastus lateralis muscle, and rectal and oral administration result in comparable bioavailability and clinical effects. A reduction in the amount of propylene glycol solvent used was associated with less pain at the injection site. When diapam® was injected into an infusion tube at a rate of 5 mg/min., the rate of infusion of 5 % glucose or 0.9 % saline had to be as fast as 20 ml/min. in order to prevent visible precipitation, whereas no precipitation was observed when 301–K 2/74 was injected at the 5 mg/min. rate into infusions moving at 5 ml/min. Further clinical studies with intramuscular and intravenous 301–K 2/74 are warranted.     

Intrathecal hyperbaric bupivacaine 3 mg + fentanyl 10 microg for outpatient knee arthroscopy with tourniquet

BACKGROUND: Combination of local anesthetic and opioid enables the use of less spinal anesthetic and increases the success of anesthesia. Intrathecal opioid does not prolong motor recovery and thus should not delay discharge home. We hypothesized that 3 mg of hyperbaric bupivacaine with 10 microg of fentanyl permits fast-tracking or shorter stay in post anesthesia care unit (PACU), and earlier discharge home, compared with 4 mg of hyperbaric bupivacaine. METHODS: In this double-blind study, 100 outpatients undergoing knee arthroscopy received randomly either 4 mg of bupivacaine (B4) or 3 mg of bupivacaine + 10 microg fentanyl (B3F) intrathecally. The volume of 0.8 ml was injected at the L2/3 interspace over a 2-min period. A lateral decubitus position was maintained for 10 min. The sensory block was recorded by using thermal stimuli, and motor block was assessed according to a modified Bromage scale. Fast-tracking criteria were complete recovery of motor block, sensory block Th12 or lower and stable vital signs. RESULTS: One block (1%) failed. Motor recovery was faster in the B3F group: 60% of the patients recovered in 80 min or less compared with 28% in group B4 (P = 0.002). The PACU-time was shorter: 36 (10-103) vs. 55 (10-140) min, respectively (P = 0.005). Seventeen (B3F) vs. nine patients (B4) could bypass PACU (NS). Time to discharge home was similar in both groups. In the B3F group, 75% of the patients developed pruritus. CONCLUSION: Both solutions produced reliable spinal anesthesia for outpatient knee arthroscopy. The PACU-time was shorter in the bupivacaine-fentanyl group, but both groups reached home-readiness equally.     

Cognitive dysfunction after minor surgery in the elderly

BACKGROUND: Major surgery is frequently associated with postoperative cognitive dysfunction (POCD) in elderly patients. Type of surgery and hospitalization may be important prognostic factors. The aims of the study were to find the incidence and risk factors for POCD in elderly patients undergoing minor surgery. METHODS: We enrolled 372 patients aged greater than 60 years scheduled for minor surgery under general anesthesia. According to local practice, patients were allocated to either in- (199) or out-patient (173) care. Cognitive function was assessed using neuropsychological testing preoperatively and 7 days and 3 months postoperatively. Postoperative cognitive dysfunction was defined using Z-score analysis. RESULTS: At 7 days, the incidence (confidence interval) of POCD in patients undergoing minor surgery was 6.8% (4.3-10.1). At 3 months the incidence of POCD was 6.6% (4.1-10.0). Logistic regression analysis identified the following significant risk factors: age greater than 70 years (odds ratio [OR]: 3.8 [1.7-8.7], P = 0.01) and in- vs. out-patient surgery (OR: 2.8 [1.2-6.3], P = 0.04). CONCLUSIONS: Our finding of less cognitive dysfunction in the first postoperative week in elderly patients undergoing minor surgery on an out-patient basis supports a strategy of avoiding hospitalization of older patients when possible.     

Buprenorphine as premedication and as analgesic during and after light isoflurane-N2O-O2 anaesthesia. A comparison with oxycodone plus fentanyl

Sixty patients undergoing gynaecological laparotomies under isoflurane anaesthesia received 0.4 mg of buprenorphine sublingually or 0.12 mg/kg of oxycodone intramuscularly in random order for preanaesthetic medication. Patients premedicated with buprenorphine were given buprenorphine before, during and after anaesthesia and patients premedicated with oxycodone received fentanyl before and during anaesthesia and oxycodone after anaesthesia. Buprenorphine premedication produced less drowsiness and sedation and alleviated patients' apprehension significantly (P less than 0.05) less than oxycodone. Systolic and diastolic blood pressure and heart rate were significantly (P less than 0.05 to P less than 0.01) higher after intubation in the buprenorphine group when compared with the oxycodone plus fentanyl group. After anaesthesia, spontaneous respiration started rapidly; the return of consciousness and immediate recovery occurred at the same rate in both groups. In the recovery room moderate to severe pain was more common (P less than 0.05) in the oxycodone plus fentanyl group than in the buprenorphine group. The respiratory rate in the recovery room was lower among patients given buprenorphine, and two patients given buprenorphine developed severe respiratory depression. In the ward (2 to 24 h after operation) sublingual buprenorphine provided pain relief as good as intramuscularly administered oxycodone. No differences were noted in the incidence or severity of emetic symptoms between the groups. It is concluded that buprenorphine can provide good postoperative pain relief for gynaecological laparotomies performed under light isoflurane anaesthesia, but patients need to be monitored carefully after operation because of the possibility of respiratory depression.     

Nausea and vomiting after gynaecological laparoscopy depends upon the phase of the menstrual cycle

Postoperative nausea and vomiting were compared in 68 women with regular menstrual periods undergoing gynaecological laparoscopy. The patients were divided into four group on the basis of the phase of the menstrual cycle as follows: premenstrum-menstrum (pre + menstrum) (Pd 25-6), early follicular phase (Pd 8-12), ovulatory phase (Pd 13-15) and luteal phase (Pd 20-24). The overall incidence of nausea and vomiting was 46%. Statistically significant differences in the incidence of nausea and retching were found among the groups by regression analysis. The incidence of nausea and vomiting was highest in women undergoing laparoscopy during the luteal phase (77%), which was greater than during the follicular phase (32%) or during pre + menstruation (18%). The need for antimetic was highest in women undergoing laparoscopy during the luteal phase (69%) and this was different from the follicular (18%, P less than 0.01) and pre + menstrum (19%, P less than 0.01) phases. It is concluded that the highest incidence of postoperative nausea and vomiting after gynaecological laparoscopy occurs during the luteal phase.