Circuit change during extracorporeal membrane oxygenation: single-center retrospective study of 48 changes.

BACKGROUND: Bleeding and thrombosis induce major morbidity and mortality in patients under extracorporeal membrane oxygenator (ECMO). Circuit changes can be performed for oxygenation membrane thrombosis but are not recommended for bleeding under ECMO. The objective of this study was to evaluate the course of clinical, laboratory, and transfusion parameters before and after ECMO circuit changes warranted by bleeding or thrombosis. METHODS: In this single-center, retrospective, cohort study, clinical parameters (bleeding syndrome, hemostatic procedures, oxygenation parameters, transfusion) and laboratory parameters (platelet count, hemoglobin, fibrinogen, PaO2) were collected over the seven days surrounding the circuit change. RESULTS: In the 274 patients on ECMO from January 2017 to August 2020, 48 circuit changes were performed in 44 patients, including 32 for bleeding and 16 for thrombosis. Mortality was similar in the patients with vs. without changes (21/44, 48% vs. 100/230, 43%) and in those with bleeding vs. thrombosis (12/28, 43% vs. 9/16, 56%, P = 0.39). In patients with bleeding, numbers of bleeding events, hemostatic procedures, and red blood cell transfusions were significantly higher before vs. after the change (P < 0.001); the platelet counts and fibrinogen levels decreased progressively before and increased significantly after the change. In patients with thrombosis, numbers of bleeding events and red blood cell transfusions did not change after membrane change. No significant differences were demonstrated between oxygenation parameters (ventilator FiO2, ECMO FiO2, and PaO2) and ECMO flow before vs. after the change. CONCLUSIONS: In patients with severe and persistent bleeding, changing the ECMO circuit decreased clinical bleeding and red blood cell transfusion needs and increased platelets and fibrinogen levels. Oxygenation parameters did not change significantly in the group with thrombosis.

Including Organ Dysfunctions in a Predictive Score for Nosocomial Pneumonia After Cardiothoracic Surgery.

BACKGROUND: Clinical diagnosis of ICU-acquired pneumonia after cardiothoracic surgery is challenging. Johanson criteria (chest radiograph infiltrate, purulent tracheal secretions, fever, and leukocytosis) fail in half the cases. A high Clinical Pulmonary Infection Score (CPIS) and ≥ 2-point increase in Sequential Organ Failure Assessment (SOFA) score (SOFA↑ ≥ 2) may improve diagnosis. The aim of the study was to evaluate whether CPIS or SOFA↑ ≥ 2 contributes to predict ICU-acquired pneumonia in subjects after cardiothoracic surgery. METHODS: We used a prospective observational design. Spiegelhalter-Knill-Jones scoring systems including CPIS or SOFA↑ ≥ 2, together with other clinical and laboratory variables, were developed in a derivation cohort. A positive quantitative pulmonary sample culture was required to confirm ICU-acquired pneumonia. Area under the receiver operating characteristic curve (AUROC) was computed for each of the 2 scoring systems. The best system was evaluated in a validation cohort. RESULTS: Derivation and validation cohorts included 172 and 108 subjects, with 410 and 216 suspected ICU-acquired pneumonia episodes, respectively. AUROC was 0.53 ± 0.03 for CPIS (P = .29) and 0.54 ± 0.03 for SOFA↑ ≥ 2 (P = .29). Adding purulent tracheal secretions and leukocytosis to SOFA↑ ≥ 2 (SOFA model) increased AUROC to 0.65 ± 0.03 (P < .001). Adding catecholamine use to CPIS (CPIS model) increased AUROC only slightly, to 0.57 ± 0.03. The probabilities predicted by the SOFA model were reliable, especially when high or low. CONCLUSIONS: A clinical scoring system including at least SOFA↑ ≥ 2 increase barely improved ICU-acquired pneumonia prediction in subjects after cardiothoracic surgery.

Oxygenation versus driving pressure for determining the best positive end-expiratory pressure in acute respiratory distress syndrome.

OBJECTIVE: The aim of this prospective longitudinal study was to compare driving pressure and absolute PaO2/FiO2 ratio in determining the best positive end-expiratory pressure (PEEP) level. PATIENTS AND METHODS: In 122 patients with acute respiratory distress syndrome, PEEP was increased until plateau pressure reached 30 cmH2O at constant tidal volume, then decreased at 15-min intervals, to 15, 10, and 5 cmH2O. The best PEEP by PaO2/FiO2 ratio (PEEPO2) was defined as the highest PaO2/FiO2 ratio obtained, and the best PEEP by driving pressure (PEEPDP) as the lowest driving pressure. The difference between the best PEEP levels was compared to a non-inferiority margin of 1.5 cmH2O. MAIN RESULTS: The best mean PEEPO2 value was 11.9 ± 4.7 cmH2O compared to 10.6 ± 4.1 cmH2O for the best PEEPDP: mean difference = 1.3 cmH2O (95% confidence interval [95% CI], 0.4-2.3; one-tailed P value, 0.36). Only 46 PEEP levels were the same with the two methods (37.7%; 95% CI 29.6-46.5). PEEP level was ≥ 15 cmH2O in 61 (50%) patients with PEEPO2 and 39 (32%) patients with PEEPDP (P = 0.001). CONCLUSION: Depending on the method chosen, the best PEEP level varies. The best PEEPDP level is lower than the best PEEPO2 level. Computing driving pressure is simple, faster and less invasive than measuring PaO2. However, our results do not demonstrate that one method deserves preference over the other in terms of patient outcome. CLINICAL TRIAL NUMBER: #ACTRN12618000554268 . Registered 13 April 2018.