Examinando por Autor "Ramirez, Yennys"

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  • Miniatura
    Ítem
    Capnometry after an inspiratory breath hold, PLATCO2, as a surrogate for PaCO2 in mild to moderate Pediatric Acute Respiratory Distress Syndrome: A feasibility study
    (Wiley Periodicals, 2023-07-10) Cruces, Pablo; Moreno, Diego; Reveco, Sonia; Améstica, Marjorie; Araneda, Patricio; Ramirez, Yennys; Vásquez-Hoyos, Pablo; Díaz, Franco
    Objective: Accurate and reliable noninvasive methods to estimate gas exchange are necessary to guide clinical decisions to avoid frequent blood samples in children with pediatric acute respiratory distress syndrome (PARDS). We aimed to investigate the correlation and agreement between end‐tidal PCO2 measured immediately after a 3‐s inspiratory‐hold (PLATCO2) by capnometry and PaCO2 measured by arterial blood gases (ABG) in PARDS. Measurements and Main Results: All patients were in volume‐controlled ventilation mode. The regular end‐tidal P P CO ETCO ( ) 2 2 (without the inspiratory hold) was registered immediately after the ABG sample. An inspiratory‐hold of 3 s was performed for lung mechanics measurements, recording PETCO2 in the breath following the inspiratory‐hold. (PLATCO2). End‐tidal alveolar dead space fraction (AVDSf) was calculated as [( – )/ PP P aCO ETCO aCO ] 2 2 2 and its surrogate (S)AVDSf as [( CO – )/ CO PLAT 2 ETCO PLAT 2 P ] 2 . Measurements of PaCO2 were considered the gold standard. We performed concordance correlation coefficient (ρc), Spearman's correlation (rho), and Bland–Altmann's analysis (mean difference ± SD [limits of agreement, LoA]). Eleven patients were included, with a median (interquartile range) age of 5 (2–11) months. Tidal volume was 5.8 (5.7–6.3) mL/kg, PEEP 8 (6–8), driving pressure 10 (8–11), and plateau pressure 17 (17–19) cm H2O. Forty‐one paired measurements were analyzed. PaCO2 was higher than PETCO2 (52 mmHg [48–54] vs. 42 mmHg [38–45], p < 0.01), and there were no significant differences with PLATCO2 (50 mmHg [46–55], p > 0.99). The concordance correlation coefficient and Spearman's correlation between PaCO2 and PLATCO2 were robust (ρc = 0.80 [95% confidence interval [CI]: 0.67–0.90]; and rho = 0.80, p < 0.001.), and for PETCO2 were weak and strong (ρc = 0.27 [95% CI: 0.15–0.38]; and rho = 0.63, p < 0.01). The bias between PLATCO2 and PaCO2 was −0.4 ± 3.5 mmHg (LoA −7.2 to 6.4), and between PETCO2 and PaCO2 was −8.5 ± 4.1 mmHg (LoA −16.6 to −0.5). The correlation between AVDSf and (S)AVDSf was moderate (rho = 0.55, p < 0.01), and the mean difference was −0.5 ± 5.6% (LoA −11.5 to 10.5) Conclusion: This pilot study showed the feasibility of measuring end‐tidal CO2 after a 3‐s end‐inspiratory breath hole in pediatric patients undergoing controlled ventilation for ARDS. Encouraging preliminary results warrant further study of this technique.
  • Miniatura
    Ítem
    Plateau pressure and driving pressure in volume- and pressure- controlled ventilation: comparison of frictional and viscoelastic resistive components in Pediatric Acute Respiratory Distress Syndrome
    (Society of Critical Care Medicine​ and The World Federation of Pediatric Intensive and Critical Care Societies, 2023-09) Cruces, Pablo; Moreno, Diego; Reveco, Sonia; Ramirez, Yennys; Díaz, Franco
    Objectives: To examine frictional, viscoelastic, and elastic resistive components, as well threshold pressures, during volume-controlled ventilation (VCV) and pressure-controlled ventilation (PCV) in pediatric patients with acute respiratory distress syndrome (ARDS). Measurements and main results: All patients were in VCV mode during measurement of pulmonary mechanics, including: the first pressure drop (P1) upon reaching zero flow during the inspiratory hold, peak inspiratory pressure (PIP), plateau pressure (P PLAT ), and total positive end-expiratory pressure (tPEEP). We calculated the components of the working pressure, as defined by the following: frictional resistive = PIP-P1; viscoelastic resistive = P1-P PLAT ; purely elastic = driving pressure (ΔP) = P PLAT -tPEEP; and threshold = intrinsic PEEP. The procedures and calculations were repeated on PCV, keeping the same tidal volume and inspiratory time. Measurements in VCV were considered the gold standard. We performed Spearman correlation and Bland-Altman analysis. The median (interquartile range [IQR]) for patient age was 5 months (2-17 mo). Tidal volume was 5.7 mL/kg (5.3-6.1 mL/kg), PIP cm H 2 O 26 (23-27 cm H 2 O), P1 23 cm H 2 O (21-26 cm H 2 O), P PLAT 19 cm H 2 O (17-22 cm H 2 O), tPEEP 9 cm H 2 O (8-9 cm H 2 O), and ΔP 11 cm H 2 O (9-13 cm H 2 O) in VCV mode at baseline. There was a robust correlation (rho > 0.8) and agreement between frictional resistive, elastic, and threshold components of working pressure in both modes but not for the viscoelastic resistive component. The purely frictional resistive component was negligible. Median peak inspiratory flow with decelerating-flow was 21 (IQR, 15-26) and squared-shaped flow was 7 L/min (IQR, 6-10 L/min) ( p < 0.001). Conclusions: P PLAT , ΔP, and tPEEP can guide clinical decisions independent of the ventilatory mode. The modest purely frictional resistive component emphasizes the relevance of maintaining the same safety limits, regardless of the selected ventilatory mode. Therefore, peak inspiratory flow should be studied as a mechanism of ventilator-induced lung injury in pediatric ARDS