IntroductionPost-cardiac surgery delirium is a severe complication. The circadian rhythm of melatonin secretion has been shown to be altered postoperatively.Aim of the studyIt was hypothesized that restoring normal sleeping patterns with a substance that is capable of resynchronizing circadian rhythm such as exogenous administration of melatonin may possibly reduce the incidence of postoperative delirium.Material and methodsThis paper represents a prospective clinical observational study. Two consecutive groups of 250 consecutive patients took part in the study. Group A was the control group and group B was the melatonin group. In group B, the patients received prophylactic melatonin treatment. The main objectives were to observe the incidence of delirium, to identify any predictors of delirium, and to compare the two groups based on the delirium incidence.ResultsThe incidence of delirium was 8.4% in the melatonin group vs. 20.8% in the control group (p = 0.001). Predictors of delirium in the melatonin group were age (p = 0.001) and higher EuroSCORE II value (p = 0.001). In multivariate analysis, age and EuroSCORE II value (p = 0.014) were predictors of postoperative delirium. Comparing the groups, the main predictors of delirium were age (p = 0.001), EuroSCORE II value (p = 0.001), cardio-pulmonary bypass (CPB) time (p = 0.001), aortic cross-clamping (ACC) time (p = 0.008), sufentanil dose (p = 0.001) and mechanical ventilation (p = 0.033).ConclusionsAdministration of melatonin significantly decreases the incidence of postoperative delirium after cardiac surgery. Prophylactic treatment with melatonin should be considered in every patient scheduled for cardiac surgery.

Background: Tumor necrosis factor-· (TNF-·) is involved in the pathogenesis of chronic active hepatitis C. Polymorphisms in the promoter region of the TNF-· gene can alter the TNF-· expression and modify the host immune response. The present study aimed at the correlation of the G308A TNF-· polymorphism with the response to antiviral combination therapy in chronic hepatitis C. Patients and Methods: 62 patients with HCV and 119 healthy unrelated controls were genotyped for the G308A TNF-· promoter polymorphism. The patients received 3 ! 3 million units of interferon alfa-2a and 1,000-1,200 mg ribavirin daily according to their body weight. A response was defined as absence of HCV-RNA and normalization of S-ALT after 6 months of combination therapy. Results: With respect to the allele and genotype frequency, a significant difference was not observed between controls and patients with chronic hepatitis C. Furthermore, such a difference was also not observed if responders and non-responders to antiviral therapy were compared. Conclusions: The promoter polymorphism of the TNF-· gene investigated herein is equally distributed in healthy individuals and patients with hepatitis C and does not seem to predict the response to therapy with interferon alfa-2a and ribavirin.

Predmet výskumu: Delírium po kardiochirurgických operáciách predstavuje závažnú komplikáciu. Klinická štúdia mala za úlohu posúdiť včasné rizikové faktory delíria a identifi kovať, ktoré z nich by mohli byť potenciálne modifi kované za účelom optimalizovania perioperačného manažmentu. Metodika: Pôvodná práca predstavuje prospektívnu klinickú observačnú štúdiu. Štúdia pozostáva z 250 po sebe nasledujúcich pacientov. Operačné postupy, spôsob vedenia anestézie ako aj pooperačný manažment pacientov boli realizované štandardným spôsobom. Incidencia a rizikové faktory pooperačného delíria boli analyzované v prvom kroku použitím analýzy s jednou premennou. Premenné považované za klinicky významné boli následne použité v analýze s viacerými premennými za účelom identifi kovania nezávislých rizikových faktorov delíria. Prítomnosť delíria bola hodnotená pomocou skórovacej škály-The Confusion Assessment Method for the Intensive Care Unit (CAM-ICU)-každých 12 hodín po operácii. Výsledky: Pooperačné delírium sa rozvinulo u 52 pacientov (20,8 %). Analýza s použitím jednej premennej potvrdila, že pokročilý vek (p = 0,0001), vyššia hodnota EuroSCORE II (p = 0,0001), dlhšie trvanie mimotelového obehu (p = 0,0001), dlhšie trvajúce naloženie aortálnej svorky (p = 0,0001) a dávka sufentanilu (p = 0,010) boli signifi kantne asociované so vznikom pooperačného delíria. Podávanie benzodiazepínov sa ukázalo ako intermediárny prediktor pooperačného delíria (p = 0,055). Zhrnutie: Pokročilý vek, vyššia hodnota EuroSCORE II, dlhšie trvanie mimotelového obehu a dlhšie naloženie aortálnej svorky, vyššie dávky sufentanilu podané v priebehu anestézie predstavujú všetko rizikové faktory vzniku pooperačného delíria. Jediným modifi kovateľným rizikovým faktorom pooperačného delíria bola dávka podaného sufentanilu, ktorá súvisela s dĺžkou trvania samotnej operácie. Nové preventívne stratégie a podanie nižšej dávky sufentanilu počas samotnej operácie, ako aj použitie iných opiátových prípravkov by malo byť preskúmané a v prípade priaznivých výsledkov aplikované do praxe za účelom zníženia výskytu pooperačného delíria.

Study of the relationship between ventilation parameters: monitored expiratory time constant -τedyn and breathing -trigger frequency (ftrig) and time of breathing cycle (Tcy) are main goals of this article. Parameters were analyzed during last 4±2 h before weaning from ventilation in 66 patients ventilated in pressure support mode (PSV). We have found out, that there exist mathematical relationships, observed during adequate gas exchange, yet not described. Monitored parameters are represented by τedyn, ftrig and Tcy. The analysis showed close negative correlation between Tcy and ftrig (R 2 =0.903). This implies that each increasing of τedyn causes decreasing of ftrig and vice versa. The calculation of regression equation between τedyn and Tcy outlined that Tcy = 5.2625 * τedyn + 0.1242 (R 2 =0.85). Regulation of respiratory cycles by the respiratory center in the brain is probably based on evaluation of τedyn as the τedyn probably represents a regulatory element and Tcy regulated element. It can be assumed, that respiratory center can optimize the work of breathing in order to minimize energy in system patient + ventilator. The unique relationship, described above could be useful in clinical practice for development of new ventilation modes. Key words Time constant • Weaning from ventilator • Time of breathing cycle • Breathing cycle

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