Browsing by Author "Bravo, Sebastián"

Now showing 1 - 2 of 2
  • Thumbnail Image
    Item
    Capillary refill time response to a fluid challenge or a vasopressor test: an observational, proof-of-concept study
    (2024) Hernández, Glenn; Valenzuela, Emilio Daniel; Kattan, Eduardo; Castro, Ricardo; Guzmán, Camila; Kraemer, Alicia Elzo; Sarzosa, Nicolás; Alegria, Leyla; Contreras, Roberto; Oviedo, Vanessa; Bravo, Sebastián; Soto, Dagoberto; Sáez, Claudia; Ait-Oufella, Hafid; Ospina Tascón, Gustavo; Bakker, Jan
    Background: Several studies have validated capillary refill time (CRT) as a marker of tissue hypoperfusion, and recent guidelines recommend CRT monitoring during septic shock resuscitation. Therefore, it is relevant to further explore its kinetics of response to short-term hemodynamic interventions with fluids or vasopressors. A couple of previous studies explored the impact of a fluid bolus on CRT, but little is known about the impact of norepinephrine on CRT when aiming at a higher mean arterial pressure (MAP) target in septic shock. We designed this observational study to further evaluate the effect of a fluid challenge (FC) and a vasopressor test (VPT) on CRT in septic shock patients with abnormal CRT after initial resuscitation. Our purpose was to determine the effects of a FC in fluid-responsive patients, and of a VPT aimed at a higher MAP target in chronically hypertensive fluid-unresponsive patients on the direction and magnitude of CRT response. Methods Thirty-four septic shock patients were included. Fluid responsiveness was assessed at baseline, and a FC (500 ml/30 mins) was administered in 9 fluid-responsive patients. A VPT was performed in 25 patients by increasing norepinephrine dose to reach a MAP to 80–85 mmHg for 30 min. Patients shared a multimodal perfusion and hemodynamic monitoring protocol with assessments at at least two time-points (baseline, and at the end of interventions). Results CRT decreased significantly with both tests (from 5 [3.5–7.6] to 4 [2.4–5.1] sec, p = 0.008 after the FC; and from 4.0 [3.3–5.6] to 3 [2.6 -5] sec, p = 0.03 after the VPT. A CRT-response was observed in 7/9 patients after the FC, and in 14/25 pts after the VPT, but CRT deteriorated in 4 patients on this latter group, all of them receiving a concomitant low-dose vasopressin. Conclusions Our findings support that fluid boluses may improve CRT or produce neutral effects in fluid-responsive septic shock patients with persistent hypoperfusion. Conversely, raising NE doses to target a higher MAP in previously hypertensive patients elicits a more heterogeneous response, improving CRT in the majority, but deteriorating skin perfusion in some patients, a fact that deserves further research.
  • No Thumbnail Available
    Item
    Machine learning analysis of a Chilean breast cancer registry
    (2021) Acevedo, Francisco; Causa, Leonardo; Bravo, Sebastián; García, Pablo; Cuevas, Ricardo; Bravo, Maria Loreto; Avellaira, Carla; Muñiz, Sabrina; Petric, Militza; Martinez, Raúl; Guerra, Constanza; Navarro, Marisel; Taramasco, Carla; Sanchez, Cesar
    In recent years, artificial intelligence (AI) and machine learning (a form of AI) have offered valuable tools for medicine by applying and training algorithms in order to make predictions. Herein, we applied a machine learning algorithm to analyze data from a >20 year breast cancer (BC) registry elaborated in two Chilean health institutions (a public hospital and a private center) that includes a total of 4838 patients and their basic clinicalpathological characteristics. Preliminary results suggest that this cohort of patients can be subdivided into five clusters according to key variables that also correlate with overall survival and disease-free survival rates. To our knowledge this is the first Latin American report of its kind. Our laboratory is currently expanding these analyses.