The Comparative Risk of Delirium with Different Opioids: A Systematic Review.

OBJECTIVE: There is substantial evidence that the use of opioids increases the risk of adverse outcomes such as delirium, but whether this risk differs between the various opioids remains controversial. In this systematic review, we evaluate and discuss possible differences in the risk of delirium from the use of various types of opioids in older patients. METHODS: We performed a search in MEDLINE by combining search terms on delirium and opioids. A specific search filter for use in geriatric medicine was used. Quality was scored according to the quality assessment for cohort studies of the Dutch Cochrane Institute. RESULTS: Six studies were included, all performed in surgical departments and all observational. No study was rated high quality, one was rated moderate quality, and five were rated low quality. Information about dose, route, and timing of administration of the opioid was frequently missing. Pain and other important risk factors of delirium were often not taken into account. Use of tramadol or meperidine was associated with an increased risk of delirium, whereas the use of morphine, fentanyl, oxycodone, and codeine were not, when compared with no opioid. Meperidine was also associated with an increased risk of delirium compared with other opioids, whereas tramadol was not. The risk of delirium appeared to be lower with hydromorphone or fentanyl, compared with other opioids. Numbers used for comparisons were small. CONCLUSION: Some data suggest that meperidine may lead to a higher perioperative risk for delirium; however, high-quality studies that compare different opioids are lacking. Further comparative research is needed.

The Effect of Treatment of Anemia with Blood Transfusion on Delirium: A Systematic Review.

OBJECTIVES: Treating the precipitating factors of delirium is the mainstay of the prevention and treatment of delirium. We aim to investigate the role of anemia and blood transfusion within the multicomponent prevention and treatment strategy of delirium. DESIGN: Systematic review. SETTING: We included cohort studies or Randomized Controlled Trials (RCTs) that considered blood transfusion as treatment for delirium or risk factor, and had delirium as outcome. PARTICIPANTS: Hospitalized patients above 55 years old. MEASUREMENTS: We searched MEDLINE from 1946 through November 2014. Quality assessment and data extraction were performed systematically. RESULTS: We included 23 studies (n = 29,471). The majority of the studies (n = 22) had a limited quality and for one study quality was uncertain. Two studies evaluated the association between transfusion strategy and postoperative delirium and found no association. Twenty-one studies investigated blood transfusion as a risk factor for delirium. In four of the 21 studies it could be assumed that delirium occurred after transfusion. One of these studies stated that transfusion was a significant risk factor for subsequent delirium (odds ratio (OR) = 3.68, 95% confidence interval (CI) = 1.32-10.94). The other three studies found no association between transfusion and delirium. In the remaining 17 studies, it was not clear whether delirium occurred before or after transfusion, so no conclusion could be drawn on the role of transfusion in delirium development. CONCLUSION: The majority of the included studies was not suited to answer the research question properly as the time course of the beginning of delirium as to transfusion was lacking. Our review shows that there is no good quality evidence available for blood transfusion to be a risk factor for delirium or to be a preventive or treatment option.