ABSTRACT
BACKGROUND: Right ventricular failure (RVF) is a major cause of early mortality after heart transplantation (HT). Isoproterenol has chronotropic, inotropic, and vasodilatory properties which might improve right ventricle function in this setting. We aimed to investigate the hemodynamic effects of isoproterenol on patients with post-HT RVF. METHODS: We conducted a one-year retrospective observational study including patients receiving isoproterenol and dobutamine for early RVF after HT. A comprehensive multiparametric hemodynamic evaluation was performed successively at three times: no isoproterenol, low doses: 0.025 µg/kg/min and high doses: 0.05 µg/kg/min (henceforth respectively called no-iso, low-iso and high-iso). RESULTS: From June 2022 to June 2023, 25 patients, median [IQR25-75] age 54 [38-61] years, were included. Before isoproterenol introduction, all patients received dobutamine and 15 (60%) were on veno-arterial extracorporeal membrane oxygenation. Isoproterenol significantly increased heart rate from 84 [77-99] (no-iso) to 91 [88-106] (low-iso) and 102 [90-122] bpm (high-iso, p<0.001). Similarly, cardiac index raised from 2.3 [1.4-3.1] to 2.7 [1.8-3.4] and 3 [1.9-3.7] l/min/m2 (p<0.001) with concomitant increase of indexed stroke volume (28 [17-34] to 31 [20-34] and 33 [23-35] mL/m2, p<0.05). Effective pulmonary arterial elastance and pressures were not modified by isoproterenol. Pulmonary vascular resistance tended to decrease from 2.9 (1.4-3.6) WU to 2.3 (1.3-3.5) WU, p=0.06. Right ventricular ejection fraction/systolic PAP evaluating RV-PA coupling increased after isoproterenol from 0.8 to 0.9 and 1 %.mmHg-1 (p=0.001). CONCLUSIONS: In post-HT RVF, isoproterenol exhibits chronotropic and inotropic effects, thereby improving RV-PA coupling and resulting in a clinically relevant increase in the cardiac index.
ABSTRACT
BACKGROUND: Venovenous extracorporeal membrane oxygenation (VV ECMO) is frequently associated with deep sedation and neuromuscular blockades, that may lead to diaphragm dysfunction. However, the prevalence, risk factors, and evolution of diaphragm dysfunction in patients with VV ECMO are unknown. We hypothesized that the prevalence of diaphragm dysfunction is high and that diaphragm activity influences diaphragm function changes. METHODS: Patients with acute respiratory distress syndrome (ARDS) requiring VV ECMO were included in two centers. Diaphragm function was serially assessed by measuring the tracheal pressure in response to phrenic nerve stimulation (Ptr,stim) from ECMO initiation (Day 1) until ECMO weaning. Diaphragm activity was estimated from the percentage of spontaneous breathing ventilation and by measuring the diaphragm thickening fraction (TFdi) with ultrasound. RESULTS: Sixty-three patients were included after a median of 4 days (3-6) of invasive mechanical ventilation. Diaphragm dysfunction, defined by Ptr, stim ≤ 11 cmH2O, was present in 39 patients (62%) on Day 1 of ECMO. Diaphragm function did not change over the study period and was not influenced by the percentage of spontaneous breathing ventilation or the TFdi during the 1 week. Among the 63 patients enrolled in the study, 24 (38%) were still alive at the end of the study period (60 days). CONCLUSIONS: Sixty-two percent of patients undergoing ECMO for ARDS related to SARS CoV-2 infection had a diaphragm dysfunction on Day 1 of ECMO initiation. Diaphragm function remains stable over time and was not associated with the percentage of time with spontaneous breathing. CLINICALTRIALS: gov Identifier NCT04613752 (date of registration February 15, 2021).
ABSTRACT
BACKGROUND: Fulminant myocarditis is a rare and severe disease whose definite and etiological diagnoses rely on pathological examination. Albeit, myocardial biopsy can be associated with significant morbidity and mortality, its therapeutic consequences are unclear. We conducted a study to determine the diagnostic yield, the safety and the therapeutic consequences of myocardial biopsy in patients with fulminant clinically suspected myocarditis unweanable from mechanical circulatory support (MCS). METHODS: Monocenter, retrospective, observational cohort study in a 26-bed French tertiary ICU between January 2002 and February 2019. Inclusion of all fulminant clinically suspected myocarditis patients undergoing in-ICU myocardial biopsy while being on MCS. The primary endpoint was the proportion of patients classified as definite myocarditis using Bonaca criteria before and after including myocardial biopsy results. RESULTS: Forty-seven patients (median age 41 [30-47], female 53%) were included: 55% died before hospital discharge, 34% could be bridged-to-recovery and 15% bridged-to-transplant. Myocardial biopsy was endomyocardial or surgical in 36% and 64% cases respectively. Tamponade requiring emergency pericardiocentesis occurred in 29% patients after endomyocardial biopsy. After adding the biopsy results in the Bonaca classification algorithm the percentage of definite myocarditis raised from 13 to 55% (p < 0.0001). The rate of biopsy-related treatments modifications was 13%, leading to patients' recovery in only 4% patients. CONCLUSIONS: In clinically suspected myocarditis unweanable from MCS, myocardial biopsy increased the rate of definite myocarditis but was associated with a low rate of treatment modification and a significant proportion of adverse events. We believe the benefit/risk ratio of myocardial biopsy should be more carefully weighted in these frail and selected patients than suggested by actual guidelines. Further prospective studies are now needed to determine its value in patients under MCS.
ABSTRACT
BACKGROUND: The data on incidence, clinical presentation, and outcomes of ventilator-associated pneumonia (VAP) in patients with severe coronavirus disease 2019 (COVID-19) pneumonia requiring mechanical ventilation (MV) are limited. We performed this retrospective cohort study to assess frequency, clinical characteristics, responsible pathogens, and outcomes of VAP in patients COVID-19 pneumonia requiring MV between March 12th and April 24th, 2020 (all had RT-PCR-confirmed SARS-CoV-2 infection). Patients with COVID-19-associated acute respiratory distress syndrome (ARDS) requiring ECMO were compared with an historical cohort of 45 patients with severe influenza-associated ARDS requiring ECMO admitted to the same ICU during the preceding three winter seasons. RESULTS: Among 50 consecutive patients with Covid-19-associated ARDS requiring ECMO included [median (IQR) age 48 (42-56) years; 72% male], 43 (86%) developed VAP [median (IQR) MV duration before the first episode, 10 (8-16) days]. VAP-causative pathogens were predominantly Enterobacteriaceae (70%), particularly inducible AmpC-cephalosporinase producers (40%), followed by Pseudomonas aeruginosa (37%). VAP recurred in 34 (79%) patients and 17 (34%) died. Most recurrences were relapses (i.e., infection with the same pathogen), with a high percentage occurring on adequate antimicrobial treatment. Estimated cumulative incidence of VAP, taking into account death and extubation as competing events, was significantly higher in Covid-19 patients than in influenza patients (p = 0.002). Despite a high P. aeruginosa-VAP rate in patients with influenza-associated ARDS (54%), the pulmonary infection recurrence rate was significantly lower than in Covid-19 patients. Overall mortality was similar for the two groups. CONCLUSIONS: Patients with severe Covid-19-associated ARDS requiring ECMO had a very high late-onset VAP rate. Inducible AmpC-cephalosporinase-producing Enterobacteriaceae and Pseudomonas aeruginosa frequently caused VAP, with multiple recurrences and difficulties eradicating the pathogen from the lung.
