Objective:To explore the patient-ventilator interaction of neurally adjusted ventilatory assist (NAVA) in patients with severe neurological diseases.Methods:A prospective study was conducted. Sixteen severe neurological patients with tracheotomy admitted to neurosurgery intensive care unit (NSICU) of Yijishan Hospital of the First Affiliated Hospital of Wannan Medical College from September 2019 to February 2020 were enrolled. According to the random number table method, they were treated with pressure support ventilation (PSV) mode followed by NAVA mode or NAVA mode followed by PSV mode mechanical ventilation. Each mode was ventilated for 24 hours. The number of auto-triggering, ineffective trigger, double trigger, inspiratory trigger delay, premature cycling, late cycling, and patient-ventilator asynchronous time (inspiratory trigger delay time, premature cycling time, and late cycling time) within 1 minute were recorded every 8 hours for 3 minutes. The average number of asynchronies per minute, asynchrony index (AI), total AI, asynchrony time, arterial blood gas analysis, and coefficient variation (CV%) of respiratory mechanics parameters of each asynchrony type between the two modes were compared.Results:There were significant decrease in the number or AI of auto-triggering, ineffective trigger, inspiratory trigger delay, premature cycling, and late cycling with NAVA mode ventilation compared with PSV mode ventilation [auto-triggering times (times/min): 0.00 (0.00, 0.00) vs. 0.00 (0.00, 0.58), auto-triggering AI: 0.00 (0.00, 0.00) vs. 0.00 (0.00, 0.02), ineffective trigger times (times/min): 0.00 (0.00, 0.33) vs. 1.00 (0.33, 2.17), ineffective trigger AI: 0.00 (0.00, 0.02) vs. 0.05 (0.02, 0.09), inspiratory trigger delay times (times/min): 0.00 (0.00, 0.58) vs. 0.67 (0.33, 1.58), inspiratory trigger delay AI: 0.00 (0.00, 0.02) vs. 0.05 (0.02, 0.09), premature cycling times (times/min): 0.00 (0.00, 0.33) vs. 0.33 (0.08, 1.00), premature cycling AI: 0.00 (0.00, 0.01) vs. 0.02 (0.00, 0.05), late cycling times (times/min): 0.00 (0.00, 0.00) vs. 1.17 (0.00, 4.83), late cycling AI: 0.00 (0.00, 0.00) vs. 0.07 (0.00, 0.25), all P < 0.05]. But there was significant increase in the number or AI of double trigger with NAVA mode ventilation as compared with PSV mode ventilation [times (times/min): 1.00 (0.33, 2.00) vs. 0.00 (0.00, 0.00), AI: 0.04 (0.02, 0.11) vs. 0.00 (0.00, 0.00), both P < 0.05]. Total AI and incidence of total AI > 0.1 showed significant decrease during NAVA mode ventilation as compared with PSV mode ventilation [total AI: 0.08 (0.04, 0.14) vs. 0.22 (0.18, 0.46), incidence of total AI > 0.1: 37.50% (6/16) vs. 93.75% (15/16), both P < 0.01]. There was no significant difference in asynchronous time or arterial blood gas analysis between the two modes. There were significant increases in variances of peak airway pressure (Ppeak) and expiratory tidal volume (VTe) during NAVA mode ventilation as compared with PSV mode ventilation [Ppeak coefficient of variation (CV%): 11.25 (7.12, 15.17)% vs. 0.00 (0.00, 2.82)%, VTe CV%: (8.93±5.53)% vs. (4.71±2.61)%, both P < 0.05]. Conclusions:Compared with PSV mode, NAVA mode can reduce the occurrence of patient-ventilator asynchronous events, reduce the AI and the occurrence of serious patient-ventilator asynchronous events, so as to improve the patient-ventilator interaction. NAVA and PSV modes can achieve the same gas exchange effect. At the same time, NAVA mode has potential advantages in avoiding insufficient or excessive ventilation support, diaphragm protection and prevention of ventilator-induced lung injury.

The purpose of this study is to provide a culture for mouse bone marrow-derived macrophages (BMDM) and peritoneal macrophages (PM) and to characterize their molecular and cellular biology. The cell number and purity from the primary culture were assessed by cell counter and flow cytometry, respectively. Morphological features were evaluated by inverted microscope. Phagocytosis by macrophages was detected by the neutral red dye uptake assay. Phenotypic markers were analyzed by real-time fluorescent quantitative PCR. Our results show that the cell number was much higher from culture of BMDM than PM, while there was no significant difference regarding the percentage of F4/80+CD11b+ cells (98.30%±0.53% vs. 94.83%±1.42%; P>0.05). The proliferation rate of BMDM was significantly higher than PM in the presence of L929 cell conditioned medium, by using CCK-8 assay. However, PM appeared to adhere to the flask wall and extend earlier than BMDM. The phagocytosis capability of un-stimulated BMDM was significantly higher than PM, as well as lipopolysaccharide (LPS)-stimulated BMDM, except the BMDM stimulated by low dose LPS (0.1 μg/mL). Furthermore, Tnfα expression was significantly higher in un-stimulated BMDM than PM, while Arg1 and Ym1 mRNA expression were significantly lower than PM. The expression difference was persistent if stimulated by LPS+IFN-γ or IL-4. Our data indicate that bone marrow can get larger amounts of macrophages than peritoneal cavity. However, it should be aware that the molecular and cellular characteristics were different between these two culture systems.
Animals ; Bone Marrow Cells ; physiology ; Cells, Cultured ; Culture Media, Conditioned ; Lipopolysaccharides ; metabolism ; Macrophages ; classification ; physiology ; Mice ; Phagocytosis