Objective To explore the effect of lung strain on breathing mechanics in dogs with acute respiratory distress syndrome (ARDS).Methods Twenty-four healthy male Beagle dogs were recruited to reproduce medium ARDS models with venous injection of 0.18 mL/kg oleic acid, and they were randomly assigned to five groups with random numbers table method. In lung protective ventilation (LPV) group (n = 4), the ventilation was supported for 24 hours with tidal volume (VT) at 6-8 mL/kg, and in lung strain 1.0, 1.5, 2.0, 2.5 groups (S1.0, S1.5, S2.0, S2.5 groups), the VT was calculated from lung strain, the volume recruitment by positive end expiratory pressure (VPEEP) and functional residual capacity (FRC). Five groups were given mechanical ventilation for 24 hours or until reaching the end point of the experiment [when the dosage of norepinephrine was higher than 1.4μg·kg-1·min-1, the blood pressure was still lower than 60 mmHg (1 mmHg = 0.133 kPa) for more than 30 minutes, which was regarded as the end point of the experiment]. Static lung compliance (Cst), airway plateau pressure (Pplat) and lung stress during the experiment were recorded. Linear regression analysis was used to fit the regression equations of lung strain and Cst descending rate,Pplat and lung stress for analyzing their relationships.Results The VT of group LPV was (7.1±0.5) mL/kg. With the increase of lung strain, VT was gradually increased. VT of group S1.0 [(7.3±1.8) mL/kg] was similar to group LPV. VT of groups S1.5, S2.0, S2.5 was significantly higher than that of group LPV (mL/kg: 13.3±5.5, 18.7±5.4, 20.1±7.4 vs. 7.1±0.5, allP < 0.05). Moreover, under the same lung strain, the difference in VT among individuals was large. The Cst of each group was decreased significantly at the end of the experiment as compared with that before model reproduction. With the increase of lung strain, the rate of Cst descending was increased, Cst dropped more significantly in groups S2.0 and S2.5 than that in groups S1.0 and S1.5 [(48.0±15.0)％, (54.4±9.5)％ vs. (25.9±13.7)％, (38.6±8.1)％, all P < 0.05]. Pplat and pulmonary stress at model reproduction in all groups were significantly higher than those before model reproduction, and they increased with the prolongation of ventilation time. Pplat and lung stress at 4 hours of ventilation in group S1.5 were significantly higher than those in group LPV [Pplat (cmH2O, 1 cmH2O = 0.098 kPa):26.2±2.3 vs. 20.2±4.2, lung stress (cmH2O): 20.5±2.0 vs. 16.6±2.5, bothP < 0.05], and they increased with lung strain increasing till to the end of experiment. It was shown by correlation analysis that lung strain was positively related with Cst descending rate, Pplat and lung stress at 4 hours of ventilation (rvalue was 0.716, 0.660, 0.539, respectively, allP < 0.05), which indicated a strong linear correlation. It was shown by fitting linear regression analysis that when lung strain increased by 1, Cst descending rate increased by 19.0％ [95％ confidence interval (95％CI) = 14.6-23.3, P = 0.000], Pplat increased by 10.8 cmH2O (95％CI = 7.9-13.7,P = 0.002), and the lung stress increased by 7.4 cmH2O (95％CI = 4.7-10.2,P = 0.002).Conclusion In animal ARDS models, the larger the lung strain, the higher the Pplat and lung stress during mechanical ventilation, VT originated for lung strain 2.0 and 2.5 may further reduce Cst in ARDS models, when lung strain over 1.5, Pplat and lung stress increased significantly, which exceeded the safe range of LPV (35 cmH2O and 25 cmH2O, respectively), and further aggravated ventilator induced lung injury (VILI).

Objective To explore the effect of noninvasive ventilation (NIV) with helmet or facial mask on clinical efficacy, tolerability, and prognosis in patients with acute respiratory failure. Methods Fifty patients with acute respiratory failure according to the inclusion criteria were recruited from January 2018 to July 2018 in Emergency Intensive Care Unit of the First Affiliated Hospital of Zhengzhou University. Included patients were randomly allocated into the helmet group or facial mask group. Based on conventional drug therapy, pressure support mode was performed with the interface of the helmet or facial mask. Oxygenation index, arterial carbon dioxide partial pressure, and respiratory rates were measured before and after the treatment, and the data were compared and analyzed by the repeated measures ANOVA. Tolerance score, complication rate, tracheal intubation rate, and mortality rate were recorded at each observation time point of the two groups. Results The oxygenation index before NIV, at 4 h and at the end of NIV treatment of the helmet group were significantly increased from (160.29±50.32) mmHg to (249.29±83.47) mmHg and (259.24±87.09) mmHg; the oxygenation index of the facial mask group were increased from (168.63±38.63) mmHg to (225.00±74.96) mmHg and (217.69±77.80) mmHg, and there was no significant difference within the two groups (P <0.05). The respiratory rates before NIV, at 4 h and at the end of NIV treatment of the helmet group were obviously decreased from (27.60±7.64) breaths/min to (17.92±4.55) breaths/min and (16.88±3.90) breaths/min; the respiratory rates of the facial mask group were decreased from (24.68±6.14) breaths/min to (20.36±4.25) breaths/min and (19.68±3.34) breaths/min, and the differences within the two groups were statistically significant (P <0.05). However, there were no significant differences on oxygenation index and respiratory rates between the helmet group and facial mask group (P >0.05). Patients in the helmet was better tolerated than those in the facial mask group [ratio of good tolerance 96％ (24/25) vs 56％ (14/25) (P = 0.001) and fully tolerance 80％ (20/25) vs 36％ (9/25) (P =0.002)] and had less complications (1/25 vs 10/25, P = 0.002). 84％ patients in the helmet group and 76％ patients in the facial mask group were successfully weaned and discharged after NIV treatment (P =0.480). Conclusions Similar clinical efficacy in improving blood gas exchange and relieving dyspnea were observed in the helmet group and the facial mask group in patients with acute respiratory failure. However, the helmet is better tolerant, and had lower complication rate, which is especially suitable for patients with chest trauma combined with facial injuries.

Objective To investigate the effect of extracorporeal membrane oxygenation (ECMO) on critical patients with non-pulmonary primary disease in the emergency department. Methods The literature of English and Chinese clinical studies on the ECMO treating critical patients with non-pulmonary primary disease published before August 2017 were electronically searched on PubMed, Embase and other databases. The obtained articles were selected, their qualities were strictly evaluated, and the in-hospital survival rate, 3-month, 6-month and 1-year survival rate, as well as the average intensive care unit (ICU) and length of hospital stay were extracted. This meta-analysis were performed using RevMan software (Version 5.0, Cochrane collaboration). Results A total of 11 articles (n=3043) were enrolled including 616 cases of ECMO treatment group and 2427 cases of control group. Fitting results showed that compared with the traditional treatment, application of ECMO can improve the in-hospital survival rate[52.1％(321/616) vs. 32.1％ (780/2427); OR=2.02; 95％CI:1.11-3.67, P=0.02] and the survival rate more than 90 days[42.1％ (61/145) vs. 17.1％ (38/222); OR=3.98; 95％CI:2.30-6.89, P<0.01];and prolong the average length of hospital stay (MD=-5.35, 95％CI:-8.10--2.60, P<0.01) and ICU time(MD=-8.99, 95％CI:-8.20--1.80, P<0.01). Conclusions Meta-analysis of existing studies showed that application of ECMO can improve the short-term and long-term prognosis of critical patients with non-pulmonary primary disease. However, due to the small number of studies and the large heterogeneity of the study population, it is necessary to carry out more, large samples and high quality randomized controlled clinical trials.

Objective:To investigate the effect and tolerance of non-invasive ventilation (NIV) with helmet in patients with respiratory failure caused by acute exacerbation of chronic obstructive pulmonary disease (AECOPD) and the effect on improving blood gas, alleviating dyspnea and the occurrence of complications.Methods:Patients with AECOPD and respiratory failure admitted to emergency intensive care unit (EICU) and respiratory intensive care unit (RICU) of the First Affiliated Hospital of Zhengzhou University from January 1st, 2018 to May 31st, 2019 were enrolled. After obtaining the informed consent of the patients or their authorized family members, the patients were divided into two groups: the helmet group and the facial mask group by random number table. NIV was carried out by using helmet or facial mask, respectively. During the course of NIV (immediately, 1 hour, 4 hours and at the end of NIV), the tolerance score, blood gas analysis, heart rate (HR), respiratory rate (RR) of patients were monitored, and the incidence of tracheal intubation, in-hospital mortality and complications were observed. Kaplan-Meier survival curve was plotted to analyze the 30-day cumulative survival of the two groups.Results:A total of 82 patients with AECOPD and respiratory failure were included during the study period. After excluding patients with the oxygenation index (PaO 2/FiO 2) > 200 mmHg (1 mmHg = 0.133 kPa), with tracheal intubation or invasive ventilation, suffering from acute myocardial infarction, severe trauma within 2 weeks, excessive secretion, sputum discharge disorder or refusal to participate in the study, 26 patients were finally enrolled in the analysis, randomly assigned to the helmet group and the facial mask group, with 13 patients in each group. The PaO 2/FiO 2 after NIV of patients in both groups was increased significantly as compared with that immediately after NIV, without significant difference between the two groups, but the increase in PaO 2/FiO 2 at the end of NIV compared with immediately after NIV in the helmet group was significantly higher than that in the facial mask group (mmHg: 75.1±73.2 vs. 7.7±86.0, P < 0.05). RR at each time point after NIV in the two groups was lower than that immediately after NIV, especially in the helmet group. There were significant differences between the helmet group and facial mask group at 1 hour, 4 hours, and the end of NIV (times/min: 17.5±4.1 vs. 23.1±6.3 at 1 hour, 16.2±2.5 vs. 20.0±5.5 at 4 hours, 15.5±2.5 vs. 21.2±5.9 at the end of NIV, all P < 0.05). The NIV tolerance score of the helmet group at 4 hours and the end was significantly higher than that of the facial mask group (4 hours: 3.9±0.3 vs. 3.3±0.9, at the end of NIV: 3.8±0.6 vs. 2.9±0.9, both P < 0.05). There was no significant difference in the improvement of pH value, arterial partial pressure of carbon dioxide (PaCO 2), or HR between helmet group and facial mask group. The total number of complications (cases: 3 vs. 8) and the nasal skin lesions (cases: 0 vs. 4) in the helmet group were significantly less than those in the facial mask group (both P < 0.05). Only 2 patients in the helmet group received endotracheal intubation, and 1 of them died; 5 patients in the facial mask group received endotracheal intubation, and 3 of them died; there was no significant difference between the two groups (both P > 0.05). The Kaplan-Meier survival curve analysis showed that the cumulative survival rate of 30 days in the helmet group was lower than that in the facial mask group, but the difference was not statistically significant (Log-Rank test: χ 2 = 1.278, P = 0.258). Conclusion:NIV with helmet has better comfort for patients with AECOPD combined with respiratory failure, and better effect on improving oxygenation and relieving dyspnea, and its effect on carbon dioxide emissions is not inferior to that of traditional mask NIV.

Background The health effects of forest therapy have been widely recognized, while the previous studies mostly focused on a single activity mode of forest walks. The effects of different types of forest therapy activities remain unclear. Objective To explore the effects of short-term forest therapy on cardiopulmonary health, psychological health, and sleep quality, and the health effects of different types of forest therapy activities, aiming to provide population empirical study data for the development of forest therapy. Methods A self-control study was conducted in a national forest park in suburb of Beijing from August to September 2018. A total of 31 healthy college students were recruited as the study subjects, with a total forest stay for 3 days and 2 nights. During the period of study, each subject practiced walking therapy, sitting therapy with five senses experience (sitting therapy thereafter), and handmade work therapy, successively. Each type of forest therapy lasted about 2 h. Changes of blood pressure, oxygen saturation (SpO₂), lung function, and fractional exhaled nitric oxide (FeNO) were estimated by measuring corresponding indicators before and after the forest therapy. Psychological health and sleep quality were assessed by Profile of Mood States and Pittsburgh Sleep Quality Index respectively at the same time. Mixed effects models were used to analyze the changes of these health indicators. The health effects of different types of forest therapy activities were further analyzed. Results The average age and body mass index of subjects in this study were (24.5±2.6) years and (20.7±1.7) kg·m⁻², respectively. After a short-term forest therapy, the selected indicators of cardiopulmonary health, psychological health, and sleep quality of subjects were all improved. In particular, the pulse pressure (PP) and FeNO decreased by 3.02 mmHg and 1.10 ppb, respectively, while the SpO₂ and peak expiratory flow (PEF) increased by 0.65% and 0.50 L·s⁻¹, respectively, and the negative emotion and global sleep quality also presented significant positive changes (all P<0.05). Furthermore, different therapy activities presented differential effects in the health indicators. Walking therapy significantly improved pulmonary function, SpO₂, and confusion (CON) emotion, in which the SpO₂, forced expiratory volume in the first second (FEV₁), and forced vital capacity (FVC) increased by 0.48%, 0.14 L, and 0.12 L, respectively, and the score of CON decreased by 0.97 (all P<0.05). Sitting therapy significantly reduced blood pressure and tension (TEN) emotion of subjects, including a decrease of the systolic blood pressure (4.45 mmHg), PP (4.19 mmHg), and the score of TEN (0.84) (all P<0.05). The diastolic blood pressure (DBP) increased slightly after handmade work therapy (ΔDBP=2.44 mmHg, P=0.016), but there were no significant changes in other indicators. Conclusion Short-term forest therapy could significantly improve cardiopulmonary health, psychological health, and sleep quality of young healthy individuals, and different types of forest therapy activities may have differential health effects.