Objective To study the positive end-expiratory pressure (PEEP) adjustment after recruitment maneuver during acute respiratory distress syndrome (ARDS) especially in the presence of tonic diaphragm electrical activity (Tonic EAdi) in order to obtain optimum PEEP and in turn to get successful oxygenation.Methods Rabbit model of ARDS was nade by intratracheal instillation of hydrochloric acid.After sufficient recruitment maneuvers,the rabbits were randomly (random number) divided into two groups,namely Tonic EAdi group ( n =5 ) and maximum oxygenation group ( n =5 ).In Tonic EAdi group,the regulation of PEEP was guided by Tonic EAdi.In maximum oxygenation group,PEEP was adjusted as per maximum oxygenation.The differences in magnitude of PEEP,pulmonary mechanics,gas exchange and hemodynamics were compared between two groups.The t-test was used to compare continuous variables between the two independent samples,and the difference was statistically significant when P ＜ 0.05.Results (1) PEEP:The PEEP was (10.7 + 1.4) cmH2O (1 cm H2O=0.098 kPa) in Tonic EAdi group and (10.0 ± 2.8) cm H2O in maximum oxygenation group (P ＞ 0.05). (2) Pulmonary mechanics:After PEEP adjustment,there was no significant difference in tidal volume ( Vr),peak pressure (Ppeak) and mean pressure (Pmean) between the two groups (P ＞ 0.05 ).(3) Gas exchange:After PEEP adjustment,there was no significant difference in oxygenation index (PaO2/FiO2) and partial pressure of arterial carbon dioxide ( PaCO2 ) between the two groups (P ＞ 0.05).Conclusions Tonic EAdi could be a good indicator for regulating PEEP in ARDS.

Objective To evaluate the effect of the pulmonary stretch reflex on the lung injury in acute respiratory distress syndrome (ARDS). Method ARDS models of rabbits were induced by intratracheal infusion hydrochloric acid and ventilated with neurally adjusted ventilatory assist (NAVA) with a tidal volume ( VT) of 6 mL/kg and the electrical activity of diaphragm ( Eadi)-determined PEEP level. The rabbits were randomly ( random number) divided into two groups: ( 1 ) sham operation (Sham) group ( n = 5 ),(2) bilateral vagotom (VAG) group( n = 5 ). Gas exchange and pulmonary mechanics were determined at baseline, after lung injury and ventilation 1, 2, 3 h respectively. Indices about pulmonary permeability,pathological changes and inflammatory response were also measured. Results Compared with Sham group,the PaO2/FiO2in VAG group decreased significantly at ventilation 2 h, 3 h (P ＜0.05). There was no significant difference on PaCO2 between Sham and VAG group (P ＞ 0.05 ), and VAG group had the higher VT,peak pressure ( Ppeak), mean pressure (Pm) compared with Sham group at the time point of ventilation 1 h, 2 h, 3 h (P＜0.05). Compared with Sham group, the dead space fraction (VD/VT) and the respiratory system elastance (Ers) in VAG group increased (P ＜ 0.05 ) and the static pulmonary compliance (Cst)decreased markedly (P ＜ 0.05 ) after 3 h ventilation. The wet/dry weight (W/D), lung injury score, tumor necrosis factor-α ( TNF-α), interleukin-8 ( IL-8 ), myeloperoxidase ( M PO ) and malondialdehyde ( M DA )in VAG group elevated significantly when compared with Sham group ( P ＜ 0.05 ). Conclusions The lung injury in ARDS was aggravated after bilateral vagotomy, which demonstrated that the pulmonary stretch reflex may have the lung protective effect.

Objective To evaluate the predictive performance of neuro-mechanical coupling (NMC) and neuro-ventilatory coupling (NVC) in the weaning outcome in patients with chronic obstructive pulmonary disease (COPD). Methods Sixteen patients were enrolled when the criteria for their first spontaneous breathing trial (SBT) was met. A 30-minute SBT was attempted, with the measurement of electrical activity of the diaphragm (Edi) , NMC, NVC, NVC ×NMC, index of rapid shallow breathing (f/Vt) , airway occlusion pressure (P0.1) and f/Vt ×P0.1 at 0, 5 and 30 min. The receiver operating characteristic (ROC) curve was calculated to evaluate the predictive performance of each index. Results Successful weaning(S group) was observed in 6 patients while weaning failure(F group) in 10 patients. (1)The predictive capacity of Edi: at 30 min of SBT, Edi showed higher values in the F group (P ＜ 0. 05), the area under the ROC curves(AUC) was 0. 817(P ＜0. 05). (2) The predictive capacity of NVC and NMC:at 5, 30 min of SBT, NVC and NMC showed higher values in the S group (P ＜0. 05); at 30 min of SBT NVC presented the largest AUC than any other time of SBT (0. 822, P ＜ 0. 05), while the AUC of NMC was 0. 800 (P ＞ 0. 05). (3) The predictive capacity of NVC × NMC: at 30 min of SBT, the AUC of NVC × NMC was larger than NVC (0. 864, P ＜ 0. 05) , showing greater sensitivity (100. 0%) and specificity (83. 3%) .(4) The predictive capacity of f/Vt and P0.1: f/Vt and f/Vt × P0.1 presented poor predictive performance in the failed patients. Conclusions Edi, NVC and NVC × NMC were good predictor for the weaning outcome in patients with COPD.

Objective:To investigate the efficacy of therapeutic plasma exchange with continuous renal replacement therapy in patients with early septic shock.Methods:A total of 55 patients with septic shock admitted to ICU of Mindong Hospital Affiliated to Fujian Medical University from December 2017 to December 2020 were retrospectively analyzed. The patients were divided into the therapeutic plasma exchange group ( n=29) and standard-therapy group ( n=26) according to whether plasma exchange combined with hemofiltration was used. Patients in both groups were treated according to the 2016 Surviving Sepsis Campaign guidelines. No hemofiltration or/and plasma exchange therapy was performed in the standard-therapy group. In the therapeutic plasma exchange group, hemofiltration was performed immediately after plasma exchange within 24 h. The inflammatory indexes, hemodynamic indexes, organ function scores and 28-day mortality were monitored before and 24 h after treatment. χ2 test was used for counting data, t-test was used for measurement data, and Kaplan-Meier curve was used to evaluate 28-day survival status. Results:(1) There were no differences in sex, age, underlying diseases, acute physiology and chronic health evaluationⅡ (APACHEⅡ) score and sequential organ failure assessment (SOFA) score before treatment between the two groups. (2) There were no significant differences in PCT, CRP and IL-6 between the two groups at enrollment. After treatment, PCT, CRP and IL-6 in the therapeutic plasma exchange group were significantly lower than those in the standard-therapy group [PCT (ng/mL): (50.07±14.54) vs. (57.93±13.42), P=0.043; CRP (mg/L): (85.71±46.05) vs. (115.10±44.42), P=0.042; IL-6 (pg/mL): (5 957.45±2 344.48) vs. (7 522.94±3 218.94), P=0.043], but there was no significant difference in WBC between the two groups. (3) There were no significant differences in norepinephrine dose, mean arterial pressure, heart rate, systemic vascular resistance index (SVRI), extravascular lung water index (EVLWI) and Lactate level between the two groups. After treatment, the norepinephrine dose, lactate level and EVLWI in the therapeutic plasma exchange group decreased significantly, while SVRI increased significantly {norepinephrine dose [μg/(kg·min): (0.76±0.39) vs. (0.54±0.39), P=0.044; lactate (μmmol/ L): (7.74±4.22) vs. (4.51±1.62), P<0.001; EVLWI (mL/kg): (10.04±2.77) vs. (8.23±2.23), P=0.008; SVRI (dyn·s/cm 2): (1 103.14±364.94) vs. (1 403.31±264.46), P=0.001}. Compared with the standard-therapy, the 24-h intravenous infusion volume was significantly decreased [(3 852.07±686.43) mL vs. (4 474.81±572.71) mL, P=0.001]. (4) There were no significant differences in APACHEⅡscore and SOFA score between the two groups at enrollment. After treatment, the APACHEⅡscore and SOFA score of the therapeutic plasma exchange group were significantly lower than those of the standard-therapy group [APACHEⅡscore: (14.07±4.30) vs. (19.23±5.44), P<0.001; SOFA score: (9.93±1.16) vs. (11.69±1.81), P<0.001)]. There were no significant differences in ICU mortality and 28-day mortality between the two groups ( P>0.05). Conclusions:Therapeutic plasma exchange with continuous renal replacement therapy can reduce the inflammatory response and improve hemodynamics in patients with septic shock. However, 24 h treatment did not improve the mortality of patients.