Maria Fountoulaki

Background: Dexmedetomidine (Dex) is a well-known a2-adrenoceptor agonist with sedative, anxiolytic, sympatholytic, and analgesic effects that has been used principally as adjuvant sedation in the ICU. The enhanced clinical experience of Dex’s use and its physiological effects encourage its application beyond the initial indications. Aim: The purpose of this review is to summarize the current knowledge of Dex’s recently expanded applications in critically ill intensive care unit (ICU) adult patients. Methods: It is a narrative review that critically examines studies published since 2015 and referring to Dex’s use in ICU patients. Results: Despite the preliminary applications and the weak existing recommendation, the unique arousable sedation, in combination with mild opioid-spare analgesic effects, has been confirmed to effectively improve ICU outcomes. Moreover, the anxiolytic and sympatholytic actions have proved to sufficiently enhance sleep quality and prevent and treat ICU delirium and post-ICU syndrome, especially among elderly patients. Recently, increasing evidence advocates for promising neuro-, renal-, and cardio-protective and anti-inflammatory effects of Dex, which are attributed to autophagy and apoptosis inhibition and sympatholytic and ischemia/reperfusion (I/R) injury-protective effects. Conclusions: Beyond sedation, Dex seems to present promising neuroprotective, anti-inflammatory, and immunomodulating effects.

Background/Objectives: The aim of this study is to assess whether changes in Pulse Pressure Variation (PPV) and Stroke Volume Variation (SVV) following a VtC can predict the response to fluid administration in patients undergoing surgery under general anesthesia with protective mechanical ventilation. Methods: A total of 40 patients undergoing general surgery or vascular surgery without clamping the aorta were enrolled. Protective mechanical ventilation was applied, and the radial artery was catheterized in all patients. The protocol began one hour after the induction of general anesthesia and the stabilization of hemodynamic parameters. The parameters PPV₆ and SVV₆ were recorded during ventilation with a Vt of 6 mL/kg Ideal Body Weight (IBW) (T1). Then, the Vt was increased to 8 mL/kg IBW for 3 min without changing other respiratory parameters. After the VtC, the parameters PPV₈ and SVV₈ (T2) were recorded. After the stabilization of hemodynamic parameters, volume expansion (VE) was administered with colloid fluid of 6 mL/kg IBW. Parameters before (T3) and 5 min after fluid challenge (T4) were recorded. The change in the Stroke Volume Index (SVI) before and after VE was used to indicate fluid responsiveness. Patients were classified as fluid responders (SVI ≥ 10%) or non-responders (SVI < 10%). Results: The parameter ΔPPV(6–8) demonstrated good predictive ability to predict fluid responsiveness, evidenced by an Area Under the Curve (AUC) of 0.86 [95% Confidence Interval (CI) 0.74 to 0.95, p < 0.0001]. The threshold of ΔPPV(6–8) exceeding 2% identified responders with a sensitivity of 83% (95% CI 0.45 to 1.0, p < 0.0001) and a specificity of 73% (95% CI 0.48 to 1.0, p < 0.0001). The parameter ΔSVV(6–8) also revealed good predictive ability, reflected by an AUC of 0.82 (95% CI 0.67 to 0.94, p < 0.0001). The criterion ΔSVV(6–8) greater than 2% pinpointed responders with a sensitivity of 83% (95% CI 0.71 to 1.0, p < 0.001) and a specificity of 77% (95% CI 0.44 to 1.0, p < 0.001). Conclusions: This study demonstrates that VtC possesses good predictive ability for fluid responsiveness in patients undergoing general surgery.

Adolescents often experience insufficient sleep and have unhealthy sleep habits. Our aim was to investigate the sleep patterns of secondary education students in Heraklion, Crete, Greece and their association with school performance and health habits. We conducted a community-based cross-sectional study with 831 students aged 13–19 years who completed an online self-reported questionnaire related to sleep and health habits. The data are mostly numerical or categorical, and an analysis was performed using t-tests, chi-square tests and multiple logistic regression. During weekdays, the students slept for an average of 7 ± 1.1 h, which is significantly lower than the 7.8 ± 1.5 h average on weekends (p < 0.001). Nearly 79% reported difficulty waking up and having insufficient sleep time, while 73.8% felt sleepy at school at least once a week. Having sufficient sleep time ≥ 8 h) was positively correlated with better academic performance (OR: 1.48, CI: 1.06–2.07, p = 0.022) and frequent physical exercise (never/rarely: 13.5%, sometimes: 21.2%, often: 65.3%; p = 0.002). Conversely, there was a negative correlation between adequate sleep and both smoking (OR: 0.29, CI: 0.13–0.63) and alcohol consumption (OR: 0.51, CI: 0.36–0.71, p = 0.001). In conclusion, this study shows that students in Heraklion, Crete frequently experience sleep deprivation, which is associated with compromised academic performance, reduced physical activity and an increased likelihood of engaging in unhealthy behaviors like smoking and alcohol consumption.