The impact of remote ischemic preconditioning on cardiac biomarker and functional response to endurance exercise.

Remote ischemic preconditioning (RIPC; repeated short reversible periods of ischemia) protects the heart against subsequent ischemic injury. We explored whether RIPC can attenuate post-exercise changes in cardiac troponin T (cTnT) and cardiac function in healthy individuals. In a randomized, crossover design, 14 participants completed 1-h cycling time trials (TT) on two separate visits; preceded by RIPC (arms/legs, 4 × 5-min 220 mmHg), or SHAM-RIPC (20 mmHg). Venous blood was sampled before and 0-, 1-, and 3-h post-exercise to assess high sensitivity (hs-)cTnT and brain natriuretic peptide (NT-proBNP). Echocardiograms were performed at the same time points to assess left and right ventricular systolic (ejection fraction; EF and right ventricular fractional area change; RVFAC, respectively) and diastolic (early transmitral flow velocities; E) function. Baseline hs-cTnT was not different between RIPC and SHAM. Post-exercise hs-cTnT levels were consistently lower following RIPC (18 ± 3 vs 21 ± 3; 19 ± 3 vs 23 ± 3; and 20 ± 2 vs 25 ± 2 ng/L at 0, 1 and 3-h post-exercise, respectively; P < 0.05). There was no main effect of time, trial, or interaction for NT-proBNP and left ventricular EF or RVFAC (all P < 0.05). A main effect of time was evident for E which transiently declined immediately after exercise to a similar level in both trials (0.85 ± 0.04 vs 0.74 ± 0.04 m/s, respectively; P < 0.05). In summary, RIPC was associated with lower hs-cTnT levels after exercise but there was no independent effect of RIPC for NT-proBNP or LV systolic and diastolic function. The lower hs-cTnT levels after RIPC suggests that further research should evaluate the role of ischemia in exercise-induced elevation in hs-cTnT.

Benzodiazepine use as a cause of cognitive impairment in elderly hospital inpatients.

BACKGROUND: Benzodiazepine drugs are used very frequently by the elderly and have been associated with a number of untoward events in them. In an earlier publication, we showed that there was an association between benzodiazepine use and episodes of confusion in hospital. The purpose of this study was to examine that association in more detail by studying only patients with intact cognitive function on admission and by taking into consideration a range of demographic, drug use, and clinical confounders. METHODS: A prospective cohort study was carried out of inpatients who had normal cognitive function on admission to hospital. The subjects were 418 hospital inpatients who had a normal result of a Mini-Mental State Examination (MMSE) performed within 24 hours of admission. They were aged 59-88 years. A clinical history and detailed drug use history were taken on admission and then the patients were followed prospectively for 10 days or until discharge, whichever was sooner. The MMSE was repeated every 2 days and all significant clinical events and episodes of delirium noted. RESULTS: 10.8% (95% Confidence Interval [CI]: 7.8-13.8%) of patients developed cognitive impairment (as indicated by a decrease in the MMSE). Factors that were statistically significantly related to the development of cognitive impairment included admission diagnoses of cancer or central nervous system (CNS) disease, alcohol consumption > 40 gms/day, hypoxia, and presence of benzodiazepines in the urine on admission. After adjusting for age, alcohol consumption, and admission diagnoses, those who reported taking benzodiazepines in daily doses equivalent to 5 mg or more of diazepam were at significantly higher risk of cognitive impairment than those who had not taken benzodiazepines (adjusted odds ratio = 3.5; 95% CI: 1.4-8.8). Twenty-one (5.0%, 95% CI: 2.9-7.1%) patients developed delirium as defined by the DSM-IIIR criteria. Age and hypoxia were statistically significantly related to the development of delirium. Due to the small number of cases of delirium, the power of the study to detect significant associations was low. CONCLUSIONS: Elderly hospital inpatients who have intact cognitive function on admission to hospital have a low risk of developing cognitive impairment and delirium during their hospital stay. In this population, however, benzodiazepine use accounted for 29% of cases of cognitive impairment which did occur. The data also suggest that dehydration, urinary retention, and an admission diagnosis of CNS disease may be important risk factors for delirium.