Propofol and sevoflurane affect intra-operative memory formation of words differently: A prospective cohort study.

BACKGROUND: Memory priming seems possible even during apparently adequate anaesthesia. However, the effects of different anaesthetics and type of stimuli, by virtue of their specific neural underpinnings, have not been considered. OBJECTIVE: To determine if intra-operative implicit memory is affected by the type of anaesthesia (propofol or sevoflurane) or by the type of stimuli (abstract or concrete words). DESIGN: Two consecutive, randomised controlled experiments. SETTING: Neurological institute in Milan, Italy. PATIENTS: Forty-three patients undergoing anaesthesia with propofol (experiment 1) and 32 patients undergoing anaesthesia with sevoflurane (experiment 2). Patients were ASA I or II, age 18 to 65 years, native Italian speakers, right-handed and without any condition affecting memory or hearing. INTERVENTION: During anaesthesia, the patients heard a list of either concrete or abstract words or no words at all (controls). Explicit memory was tested with an explicit recall task and the Brice Interview; implicit memory was assessed through a word stem completion test. OUTCOME MEASURES: The number of explicitly recalled words, positivity to the Brice Interview, the proportion of target and nontarget hits, and a derived implicit memory score. RESULTS: With propofol, the proportion of target hits was significantly greater than the proportion of nontarget hits for the concrete word experimental group (P = 0.018). The implicit memory score of the concrete word experimental group was significantly higher than the score of both the abstract word experimental group (P  = 0.000) and the concrete word control group (P = 0.023). With sevoflurane, the proportion of target hits was significantly higher than the proportion of nontarget hits for the abstract word experimental group only (P = 0.027). No patients had a BIS above 60 and no one could recall intra-operative events or words. CONCLUSION: Intra-operative memory for words can form during apparently adequate BIS-guided anaesthesia but is modified by propofol or sevoflurane acting on different brain targets. Further studies on larger samples and using neuroimaging techniques are needed. TRIAL REGISTRATION: Clinicaltrials.gov identifier: NCT03727464.

Selenium supplementation in critically ill patients: a systematic review and meta-analysis.

PURPOSE: The oxidative stress is recognized as a constant feature in critical illness. Nevertheless, the use of antioxidant therapy remains controversial. We tried to demonstrate that intravenous selenium supplementation could promote antioxidant status and help protect against infection and organ failure, improving outcome in critically ill patients. MATERIALS AND METHODS: We conducted a systematic review and meta-analysis of randomized controlled trials (RCTs) comparing the exogenous supplementation of selenium versus standard therapy without any adjuvant in critically ill adults. RESULTS: Nine RCTs met inclusion criteria. Selenium supplementation was associated with a reduction in 28-day mortality of borderline statistical significance (risk ratio = 0.84, 95% confidence interval 0.71-0.99, P = .04). The analysis of pre-defined subgroups detected no significant effects regarding the supplementation with doses of selenium ≤ 500 µg/d, administration of a load dose with a bolus and duration of treatment. Only 2 studies analyzed 6-month mortality and could not show a difference. No effects could be demonstrated on hospital length of stay, pulmonary infections, or renal failure. CONCLUSIONS: The use of high-dose selenium might be associated with a beneficial effect on 28-day mortality in critically ill patients. Nevertheless, the use of selenium as adjuvant therapy needs further evaluations.