Reliability of Respiratory System Compliance Calculation During Assisted Mechanical Ventilation: A Retrospective Study.

OBJECTIVES: To compare respiratory system compliance (C rs ) calculation during controlled mechanical ventilation (MV) and, subsequently, during assisted MV. DESIGN: This is a single-center, retrospective, observational study. SETTING: This study was conducted on patients admitted to Neuro-ICU of Niguarda Hospital (tertiary referral hospital). PATIENTS: We analyzed every patient greater than or equal to 18 years old having a C rs measurement in controlled and in assisted MV within 60 minutes. Plateau pressure (P plat ) was considered reliable if it was deemed visually stable for at least 2 seconds. INTERVENTIONS: Inspiratory pause was incorporated to detect P plat in controlled and assisted MV. Calculation of C rs and driving pressure were achieved. MEASUREMENTS AND MAIN RESULTS: A total of 101 patients were studied. An acceptable agreement was found (Bland-Altman plot bias -3.9, level of agreement upper 21.6, lower -29.6). C rs in assisted MV was 64.1 (52.6-79.3) and in controlled MV it was 61.2 (50-71.2) mL/cm H 2o ( p = 0.006). No statistical difference was found in C rs (assisted vs controlled MV) when peak pressure was lower than P plat nor when peak pressure was higher than P plat . CONCLUSIONS: A P plat visually stable for at least 2 seconds leads to reliable C rs calculation during assisted MV.

Emergently planned exclusive hub-and-spoke system in the epicenter of the first wave of COVID-19 pandemic in Italy: the experience of the largest COVID-19-free ICU hub for time-dependent diseases.

BACKGROUND: Lombardy was the epicenter in Italy of the first wave of COVID-19 pandemic. To face the contagion growth, from March 8 to May 8, 2020, a regional law redesigned the hub-and-spoke system for time-dependent diseases to better allocate resources for COVID-19 patients. METHODS: We report the reorganization of the major hospital in Lombardy during COVID-19 pandemic, including the rearrangement of its ICU beds to face COVID-19 pandemic and fulfill its role as extended hub for time-dependent diseases while preserving transplant activity. To highlight the impact of the emergently planned hub-and-spoke system, all patients admitted to a COVID-19-free ICU hub for trauma, neurosurgical emergencies and stroke during the two-month period were retrospectively collected and compared to 2019 cohort. Regional data on organ procurement was retrieved. Observed-to-expected (OE) in-ICU mortality ratios were computed to test the impact of the pandemic on patients affected by time-dependent diseases. RESULTS: Dynamic changes in ICU resource allocation occurred according to local COVID-19 epidemiology/trends of patients referred for time-dependent diseases. The absolute increase of admissions for trauma, neurosurgical emergencies and stroke was roughly two-fold. Patients referred to the hub were older and characterized by more severe conditions. An increase in crude mortality was observed, though OE ratios for in-ICU mortality were not statistically different when comparing 2020 vs. 2019. An increase in local organ procurement was observed, limiting the debacle of regional transplant activity. CONCLUSIONS: We described the effects of a regional emergently planned hub-and-spoke system for time-dependent diseases settled in the epicenter of COVID-19 pandemic in Italy.

Role of immune cells in animal models for inherited neuropathies: facts and visions.

Mice heterozygously deficient in the peripheral myelin adhesion molecule P0 (P0+/- mice) are models for some forms of Charcot-Marie-Tooth (CMT) neuropathies. In addition to the characteristic hallmarks of demyelination, elevated numbers of CD8-positive T-lymphocytes and F4/80-positive macrophages are striking features in the nerves of these mice. These immune cells increase in number with age and progress of demyelination, suggesting that they might be functionally related to myelin damage. In order to investigate the pathogenetic role of lymphocytes, the myelin mutants were cross-bred with recombination activating gene 1 (RAG-1)-deficient mice, which lack mature T- and B-lymphocytes. The immunodeficient myelin mutants showed a less severe myelin degeneration. The beneficial effect of lymphocyte-deficiency was reversible, since demyelination worsened in immunodeficient myelin-mutants when reconstituted with bone marrow from wild-type mice. Ultrastructural analysis revealed macrophages in close apposition to myelin and demyelinated axons. We therefore cross-bred the P0+/- mice with spontaneous osteopetrotic (op) mutants deficient in the macrophage colony-stimulating factor (M-CSF), hence displaying impaired macrophage activation. In the corresponding double mutants the numbers of macrophages were not elevated in the peripheral nerves, and the demyelinating phenotype was less severe than in the genuine P0+/- mice, demonstrating that macrophages are also functionally involved in the pathogenesis of genetically mediated demyelination. We also examined other models for inherited neuropathies for a possible involvement of immune cells. We chose mice deficient in the gap junction component connexin 32, a model for the X-linked form of CMT. Similar to P0-deficient mice, T-lymphocytes and macrophages were elevated and macrophages showed a close apposition to degenerating myelin. We conclude that the involvement of T-lymphocytes and macrophages is a common pathogenetic feature in various forms of slowly progressive inherited neuropathies.