Clinical question: Are a longer duration of delirium and higher doses of sedatives associated with cognitive impairment in the hospital?
Background: Survivors of critical illness are at risk for prolonged cognitive dysfunction. Delirium (and factors associated with delirium, namely sedative and analgesic medications) has been implicated in cognitive dysfunction.
Study design: Prospective cohort study.
Setting: Multi-center, academic, and acute care hospitals.
Synopsis: The study examined 821 adults admitted to the ICU with respiratory failure, cardiogenic shock, or septic shock. Patients excluded were those with pre-existing cognitive impairment, those with psychotic disorders, and those for whom follow-up would not be possible. Two risk factors measured were duration of delirium and use of sedative/analgesics. Delirium was assessed at three and 12 months using the CAM-ICU algorithm in the ICU by trained psychology professionals who were unaware of the patients’ in-hospital course.
At three months, 40% of patients had global cognition scores that were 1.5 standard deviations (SD) below population mean (similar to traumatic brain injury), and 26% had scores two SD below population mean (similar to mild Alzheimer’s). At 12 months, 34% had scores similar to traumatic brain injury patients, and 24% had scores similar to mild Alzheimer’s. A longer duration of delirium was associated with worse global cognition at three and 12 months. Use of sedatives/analgesics was not associated with cognitive impairment.
Bottom line: Critically ill patients in the ICU who experience a longer duration of delirium are at risk of long-term cognitive impairments lasting 12 months.
Citation: Pandharipande PP, Girard TD, Jackson JC, et al. Long-term cognitive impairment after critical illness. N Engl J Med. 2013;369(14):1306-1316.
Holding Chambers (Spacers) vs. Nebulizers for Acute Asthma
Clinical question: Are beta-2 agonists as effective when administered through a holding chamber (spacer) as they are when administered by a nebulizer?
Background: During an acute asthma attack, beta-2 agonists must be delivered to the peripheral airways. There has been considerable controversy regarding the use of a spacer compared with a nebulizer. Aside from admission rates and length of stay, factors taken into account include cost, maintenance of nebulizer machines, and infection control (potential of cross-infection via nebulizers).
Study design: Meta-analysis review of randomized controlled trials (RCTs).
Setting: Multi-centered, worldwide studies from community setting and EDs.
Synopsis: In 39 studies of patients with an acute asthma attack (selected from Cochrane Airways Group Specialized Register), the hospital admission rates did not differ on the basis of delivery method in 729 adults (risk ratio=0.94, confidence interval 0.61-1.43) or in 1,897 children (risk ratio=0.71, confidence interval 0.47-1.08). Secondary outcomes included the duration of time in the ED and the duration of hospital admission. Time spent in the ED varied for adults but was shorter for children with spacers (based on three studies). Duration of hospital admission also did not differ when modes of delivery were compared.
Bottom line: Providing beta-2 agonists using nebulizers during an acute asthma attack is not more effective than administration using a spacer.
Citation: Cates CJ, Welsh EJ, Rowe BH. Holding chambers (spacers) versus nebulisers for beta-agonist treatment of acute asthma. Cochrane Database Syst Rev. 2013;9:CD000052.