Objective To investigate the impact of lower inspiratory peak flow rates on airway peak pressure when using a ventilator to maintain respiratory function during the advanced life support phase of in-hospital cardiopulmonary resuscitation(CPR).Methods A prospective study was conducted,30 patients who underwent CPR for more than 20 minutes admitted to Lishui Municipal Central Hospital between September 2021 and December 2023 were enrolled as the study subjects.Volume controlled ventilation(VCV)with a descending flow waveform was used,while other preset parameters remained unchanged.Airway peak pressure was measured at different peak flow rates(55,50,45,and 40 L/min).The influence of varying flow rates on peak pressure was analyzed.Results During CPR,patients were in a continuous state of chest compressions.When the ventilator parameters were set conventionally,alarms for high airway pressure,low tidal volume(VT),and high respiratory rate often occurred,which affected the effectiveness of ventilatory support.There was a significant variation in airway peak pressure among different patients.As the peak flow rate increased from 40 L/min to 55 L/min,the airway peak pressure gradually increased.During the process of reducing the peak flow rate,the pulse oxygen saturation(SpO2)of all patients remained stable without significant changes.The 40 L/min group had significantly lower peak pressures than the 50 and 55 L/min groups,whereas the 55 L/min group had significantly higher pressures than all others[cmH2O(1 cmH2O≈0.098 kPa):41.20±9.06 vs.47.90±9.04 and 53.70±7.96,all P<0.05].When comparing patients with peak flow rates of 40 L/min and 50 L/min,as well as 45 L/min and 55 L/min,the average airway peak pressure increased significantly with each 10 L/min increment in inspiratory peak flow rate.However,the SpO2 remained essentially unchanged or slightly increased as the peak flow rate decreased.There were no statistically significant differences in SpO2 among patients at different peak flow rate levels.When the peak flow rate was set at 55,50,45,and 40 L/min,the proportions of patients with airway peak pressure>40 cmH2O were 100.0%,83.3%,63.3%,and 53.3%,respectively.Among them,the proportions of patients with airway peak pressure>50 cmH2O were 66.7%,40.0%,16.6%,and 16.6%,respectively.As the peak flow rate decreased,the proportion of patients with airway peak pressure>40 cmH2O gradually decreased.If the peak flow rate was set at 45 L/min or lower,the number of patients with airway peak pressure>50 cmH2O during CPR was less than 50.0%of the total number of cases.Conclusions During mechanical ventilation in CPR,using volume-controlled ventilation(VCV)mode with a decelerating waveform,improper peak flow rate settings can easily trigger high airway pressure alarms and result in low tidal volume(VT),leading to poor synchrony between the ventilator and the patient.Compared to peak flow rates of 55 L/min and above,selecting an inspiratory peak flow rate of 40 L/min and setting the high-pressure alarm at 50 cmH2O is suitable for the mechanical ventilation needs of most patients and does not affect oxygenation levels.This is a more appropriate choice.

Objective To investigate the impact of lower inspiratory peak flow rates on airway peak pressure when using a ventilator to maintain respiratory function during the advanced life support phase of in-hospital cardiopulmonary resuscitation(CPR).Methods A prospective study was conducted,30 patients who underwent CPR for more than 20 minutes admitted to Lishui Municipal Central Hospital between September 2021 and December 2023 were enrolled as the study subjects.Volume controlled ventilation(VCV)with a descending flow waveform was used,while other preset parameters remained unchanged.Airway peak pressure was measured at different peak flow rates(55,50,45,and 40 L/min).The influence of varying flow rates on peak pressure was analyzed.Results During CPR,patients were in a continuous state of chest compressions.When the ventilator parameters were set conventionally,alarms for high airway pressure,low tidal volume(VT),and high respiratory rate often occurred,which affected the effectiveness of ventilatory support.There was a significant variation in airway peak pressure among different patients.As the peak flow rate increased from 40 L/min to 55 L/min,the airway peak pressure gradually increased.During the process of reducing the peak flow rate,the pulse oxygen saturation(SpO2)of all patients remained stable without significant changes.The 40 L/min group had significantly lower peak pressures than the 50 and 55 L/min groups,whereas the 55 L/min group had significantly higher pressures than all others[cmH2O(1 cmH2O≈0.098 kPa):41.20±9.06 vs.47.90±9.04 and 53.70±7.96,all P<0.05].When comparing patients with peak flow rates of 40 L/min and 50 L/min,as well as 45 L/min and 55 L/min,the average airway peak pressure increased significantly with each 10 L/min increment in inspiratory peak flow rate.However,the SpO2 remained essentially unchanged or slightly increased as the peak flow rate decreased.There were no statistically significant differences in SpO2 among patients at different peak flow rate levels.When the peak flow rate was set at 55,50,45,and 40 L/min,the proportions of patients with airway peak pressure>40 cmH2O were 100.0%,83.3%,63.3%,and 53.3%,respectively.Among them,the proportions of patients with airway peak pressure>50 cmH2O were 66.7%,40.0%,16.6%,and 16.6%,respectively.As the peak flow rate decreased,the proportion of patients with airway peak pressure>40 cmH2O gradually decreased.If the peak flow rate was set at 45 L/min or lower,the number of patients with airway peak pressure>50 cmH2O during CPR was less than 50.0%of the total number of cases.Conclusions During mechanical ventilation in CPR,using volume-controlled ventilation(VCV)mode with a decelerating waveform,improper peak flow rate settings can easily trigger high airway pressure alarms and result in low tidal volume(VT),leading to poor synchrony between the ventilator and the patient.Compared to peak flow rates of 55 L/min and above,selecting an inspiratory peak flow rate of 40 L/min and setting the high-pressure alarm at 50 cmH2O is suitable for the mechanical ventilation needs of most patients and does not affect oxygenation levels.This is a more appropriate choice.

Alzheimer's disease (AD) is a leading cause of dementia in the elderly. Mitogen-activated protein kinase phosphatase 1 (MKP-1) plays a neuroprotective role in AD. However, the molecular mechanisms underlying the effects of MKP-1 on AD have not been extensively studied. MicroRNAs (miRNAs) regulate gene expression at the post-transcriptional level, thereby repressing mRNA translation. Here, we reported that the microRNA-429-3p (miR-429-3p) was significantly increased in the brain of APP23/PS45 AD model mice and N2A^APP AD model cells. We further found that miR-429-3p could downregulate MKP-1 expression by directly binding to its 3'-untranslated region (3' UTR). Inhibition of miR-429-3p by its antagomir (A-miR-429) restored the expression of MKP-1 to a control level and consequently reduced the amyloidogenic processing of APP and Aβ accumulation. More importantly, intranasal administration of A-miR-429 successfully ameliorated the deficits of hippocampal CA1 long-term potentiation and spatial learning and memory in AD model mice by suppressing extracellular signal-regulated kinase (ERK1/2)-mediated GluA1 hyperphosphorylation at Ser831 site, thereby increasing the surface expression of GluA1-containing α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors (AMPARs). Together, these results demonstrate that inhibiting miR-429-3p to upregulate MKP-1 effectively improves cognitive and synaptic functions in AD model mice, suggesting that miR-429/MKP-1 pathway may be a novel therapeutic target for AD treatment.

Objective To investigate the effects and related mechanisms of ghrelin on myocardial neovascularization in diabetic rats with experimental myocardial infarction (MI).Methods Adult male SD rats were divided into six groups (n =20 each group):control,diabetes mellitus (DM),MI,DM + MI,DM +MI + ghrelin,DM + MI + ghrelin + D-Lys3-GHRP-6 (GHSRla inhibitor).DM was induced by streptozotocin (STZ,60 mg/kg),3 months later,MI was induced by left anterior descending artery ligation in DM rats.DM + MI + ghrelin group received ghrelin 200 μg · kg-1 · d-1 and DM + MI + ghrelin + D-Lys3-GHRP-6 group received ghrelin 200 μg · kg-1 · d-1 and D-Lys3-GHRP-6 50 mg · kg-1 · d-1 for 4 weeks.Then,cardiac function was measured by echocardiography,microvascular density (MVD) was measured by CD34 immunohistochemistry,myocardial infarct size was determined by Masson staining,the mRNA and protein expressions of vascular endothelial growth factor (VEGF) and receptors Flk-1,Flt-1 were detected by real-time PCR and Western-blot,respectively.Results Compared with MI group,MVD(15.3 ± 1.0 vs.20.7 ± 1.6,P ＜ 0.05),left ventricular ejection fraction (LVEF) ((64.2 ± 3.4) ％ vs.(81.3 ±3.8) ％,P ＜ 0.01),left ventricular fractional shortening (LVFS) ((31.7 ± 1.1) ％ vs.(48.8 ± 3.3) ％,P ＜ 0.01) and the mRNA and protein expression of VEGF,Flk-1 and Flt-1 (P ＜ 0.01) were reduced,while myocardial infarct size ((55.8 ± 3.1) ％ vs.(35.7 ± 2.5) ％,P ＜ 0.01) was increased in DM + MI group.These effects were partly reversed in DM + MI + ghrelin group and the beneficial effects of ghrelin were partly abolished by D-Lys3-GHRP-6 (all P ＜ 0.05).Conclusions Our results demonstrate that ghrelin could improve microvascular density,cardiac function,and reduce myocardial infarct size of diabetic rats with myocardial infarction via modulating GHSR1 a-mediated expressions of VEGF,Flk-1 and Flt-1.