Person: Mercado, Pablo
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Mercado
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Pablo
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Pablo Vladimir Mercado Irribarren
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Publication Mitral annular plane systolic excursion for assessing left ventricular systolic dysfunction in patients with septic shock(2023) Mercado, Pablo; Brault, Clément; Zerbib, Yoann; Diouf, Momar; Michaud, Audrey; Tribouilloy, Christophe; Maizel, Julien; Slama, MichelBackground: Using easy-to-determine bedside measurements, we developed an echocardiographic algorithm for predicting left ventricular ejection fraction (LVEF) and longitudinal strain (LVLS) in patients with septic shock. Methods: We measured septal and lateral mitral annular plane systolic excursion (MAPSE), septal and lateral mitral S-wave velocity, and the left ventricular longitudinal wall fractional shortening in patients with septic shock. We used a conditional inference tree method to build a stratification algorithm. The left ventricular systolic dysfunction was defined as an LVEF <50%, an LVLS greater than -17%, or both. Results: We included 71 patients (males: 61%; mean [standard deviation] age: 61 [15] yr). Septal MAPSE (cut-off: 1.2 cm) was the best predictor of left ventricular systolic dysfunction. The level of agreement between the septal MAPSE and the left ventricular systolic dysfunction was 0.525 [0.299-0.751]. A septal MAPSE ≥1.2 cm predicted normal LVEF in 17/18 patients, or 94%. In contrast, a septal MAPSE <1.2 cm predicted left ventricular systolic dysfunction with impaired LVLS in 46/53 patients (87%), although 32/53 (60%) patients had a preserved LVEF. Conclusions: Septal MAPSE is easily measured at the bedside and might help clinicians to detect left ventricular systolic dysfunction early-especially when myocardial strain measurements are not feasible.Publication Lung recruitment maneuver improves right and left ventricular function in patients with acute respiratory distress syndrome(2025) Lambour, Alexis; Zerbib, Yoann; Mercado, Pablo; Kontar, Loay; De Cagny, Bertrand; Maizel, Julien; Slama, Michel; Brault, ClémentBACKGROUND: Lung recruitment maneuvers (LRM) and high positive end-expiratory pressure (PEEP) may benefit some patients by reopening non- or poorly aerated alveoli. However, the effects of opening the lung with LRM on hemodynamics remain uncertain. This study aimed to evaluate the direct impact of LRM on cardiac function in patients with moderate-to-severe acute respiratory distress syndrome (ARDS). METHODS: This post-hoc analysis included 34 patients with moderate-to-severe ARDS from two prospective cohort studies. The LRM consisted in a gradual increase in PEEP, starting from 25 cmH2O (PEEPpre, before the recruitment maneuver at PEEP 25 cmH2O) until reaching 40 cmH2O. After LRM, PEEP was decreased to 25 cmH2O (PEEPpost, after the recruitment maneuver, also at PEEP 25 cmH2O) followed by a decremental PEEP titration. We compared the size and function of the right ventricle (RV) and left ventricle (LV) between PEEPpre and PEEPpost. RESULTS: The respiratory system compliance significantly increased from 21 ± 7 ml/cmH2O at PEEPpre to 24 ± 7 ml/cmH2O at PEEPpost (p < 0.001), indicating effective lung recruitment. The RV end-diastolic diameter and the RV/LV ratio decreased after LRM (51 ± 11 vs. 41 ± 9 mm; p < 0.001, and 1.05 ± 0.21 vs. 0.90 ± 0.18; p < 0.001, respectively), suggesting reduced pulmonary vascular resistance. The RV free wall strain improved from -22 ± 10 to -25 ± 8% (p = 0.040). The cardiac index significantly increased from 2.1 ± 0.6 to 2.4 ± 0.7 L/min/m2 (p < 0.001) due to improved LV function, as demonstrated by a lower LV global longitudinal strain at PEEPpost (-16 ± 4% vs. -19 ± 3%, p = 0.002). CONCLUSIONS: LRM may benefit both the lungs and the heart. The increase in transpulmonary pressure leads to an expansion in aerated lung volume, potentially reducing lung overdistension and collapse, thereby lowering RV afterload and improving RV systolic function.Publication Heterogeneous cardiovascular responses to acute mean arterial pressure augmentation in septic shock: the role of ventriculo-arterial coupling and venous return(2026) Valenzuela, Emilio; Mercado, Pablo; Medel, Juan; Oviedo, Vanessa; Gabrielli, Luigi; Slama, Michel; Bakker, Jan; Castro, Ricardo; Retamal, JaimeBackground: In patients with septic shock, vasopressor-induced mean arterial pressure (MAP) augmentation is commonly used to restore tissue perfusion; however, patients may exhibit divergent cardiovascular responses despite achieving similar arterial pressure targets. We hypothesized that this heterogeneity reflects the differences in ventricular adaptation to increases in arterial load and venous return determinants. Methods: We conducted a prospective physiological observational study in mechanically ventilated adults with septic shock who underwent transient MAP augmentation from approximately 65 to 85 mmHg after the initial hemodynamic resuscitation. MAP was increased by norepinephrine dose escalation or by adding vasopressin according to clinical judgment. Comprehensive transthoracic echocardiography was performed immediately before and after MAP augmentation. Patients were classified a priori according to the relative changes in cardiac output (CO): flow recruitment (> 15% increase), stable flow (- 15% to + 15%), or flow deterioration (> 15% decrease). Changes in effective arterial elastance (Ea), end-systolic elastance (Ees), VA coupling (Ea/Ees), stroke volume, left ventricular ejection fraction (LVEF), analogue mean systemic filling pressure (Pmsa), and derived venous return variables were analyzed. Results: Thirty-two patients were included. Despite comparable increases in MAP, the cardiovascular responses were heterogeneous: 10 patients (31%) exhibited flow recruitment, 17 (53%) maintained a stable flow, and 5 (16%) developed flow deterioration. Patients with flow deterioration showed a greater increase in Ea without a proportional increase in Ees, resulting in worsening VA coupling (ΔEa/Ees + 0.22 IQR [0.01-0.81]), whereas VA coupling remained stable or improved in patients with preserved or increased flow (p = 0.035). Flow deterioration was also associated with reduced LVEF and changes in the derived venous return indices, which may have contributed to the observed reduction in forward flow. Changes in VA coupling correlated with changes in IVCT (ρ = 0.788, p < 0.0001), MPI (ρ = 0.599, p < 0.0003), stroke volume (ρ =-0.418, p = 0.017), and LVEF (ρ=-0.431, p = 0.0139). Conclusions: Acute MAP augmentation elicits heterogeneous cardiovascular responses in patients with septic shock despite similar increases in arterial pressure. Flow deterioration is characterized by worsening VA coupling, reduced stroke volume, and impaired systolic adaptation, potentially modulated by changes in the derived venous return indices.Publication Combined Approach with Ultrasound and Pressure-Volume Loops to Manage Mechanical Ventilation in Acute Hypoxemic Respiratory Failure(2026) Aguilera, Javiera; Adrião, Diana; Mercado, Pablo; Slama, Michel; De Vita, Nello; Vaschetto, Rosanna; Pozzi, Marco; Bouhemad, Belaïd; Mongodi, Silvia; Mojoli, FrancescoAcute hypoxemic respiratory failure (AHRF), particularly acute respiratory distress syndrome (ARDS), is characterized by marked heterogeneity in lung morphology and mechanics, requiring individualized mechanical ventilation strategies that balance adequate gas exchange with the prevention of ventilator-induced lung injury (VILI). Lung ultrasound (LUS) has become a cornerstone of critical care imaging, allowing differential diagnosis, quantitative assessment of lung aeration, phenotyping of ARDS morphology, and monitoring of disease evolution and complications. However, imaging alone does not provide direct guidance for optimizing ventilator settings. Some modern ventilators enable the rapid bedside acquisition of tidal pressure-volume (PV) loops, allowing tidal hysteresis to be measured and thereby providing complementary physiological information by identifying cyclic opening and closing of lung units and signs of overdistension. Emerging evidence supports the use of tidal hysteresis thresholds to identify insufficient positive end-expiratory pressure (PEEP) associated with tidal recruitment/derecruitment and to guide individualized PEEP titration during decremental PEEP trials. This review discusses the rationale and practical implementation of an integrated approach combining critical care ultrasound and PV loops throughout the management of mechanically ventilated patients with AHRF. We describe how ultrasound can support diagnosis, phenotyping, monitoring of lung aeration, and detection of ventilation-related complications, while PV loops provide a practical physiological framework for optimizing ventilator settings. This approach may provide a comprehensive, non-invasive, and repeatable bedside assessment of lung morphology, aeration, and respiratory mechanics, potentially facilitating personalized mechanical ventilation strategies aimed at reducing the risk of VILI and optimizing patient management.