Conventional Mechanical Ventilation Group Research Articles

ECMO is associated with decreased hospital mortality in COVID-19 ARDS

This study determined whether compared to conventional mechanical ventilation (MV), extracorporeal membrane oxygenation (ECMO) is associated with decreased hospital mortality or fibrotic changes in patients with COVID-19 acute respiratory distress syndrome. A cohort of 72 patients treated with ECMO and 390 with conventional MV were analyzed (February 2020–December 2021). A target trial was emulated comparing the treatment strategies of initiating ECMO vs no ECMO within 7 days of MV in patients with a PaO2/FiO2 < 80 or a PaCO2 ≥ 60 mmHg. A total of 222 patients met the eligibility criteria for the emulated trial, among whom 42 initiated ECMO. ECMO was associated with a lower risk of hospital mortality (hazard ratio [HR], 0.56; 95% confidence interval [CI] 0.36–0.96). The risk was lower in patients who were younger (age < 70 years), had less comorbidities (Charlson comorbidity index < 2), underwent prone positioning before ECMO, and had driving pressures ≥ 15 cmH2O at inclusion. Furthermore, ECMO was associated with a lower risk of fibrotic changes (HR, 0.30; 95% CI 0.11–0.70). However, the finding was limited due to relatively small number of patients and differences in observability between the ECMO and conventional MV groups.

Effects of driving pressure-guided ventilation on postoperative pulmonary complications in patients with COVID-19 undergoing abdominal surgery: A post-hoc propensity score-matched analysis

BackgroundApplication of individualized positive end-expiratory pressure (PEEP) based on minimum driving pressure facilitates to prevent from postoperative pulmonary complications (PPCs). Whether lung protective ventilation strategy can reduce the risk of PPCs in COVID-19 patients remains unclear. In this study, we compared the effects of driving pressure-guided ventilation with conventional mechanical ventilation on PPCs in patients with COVID-19. MethodsPatients infected COVID-19 within 30-day before surgery were retrospectively enrolled consecutively. Patients were divided into two group: driving pressure-guided lung protective ventilation strategy group (LPVS group) and conventional mechanical ventilation group (Control group). Propensity score matching for variables selected was used by logistic regression with the nearest-neighbor method. The outcomes were the incidence of PPCs and hypoxemia in post-anesthesia care unit. ResultsThere was no significant difference in the baseline data between both groups (P > 0.05). The incidence of PPCs (12.73 % vs 36.36 %, χ2 = 7.068, P = 0.008) and hypoxemia [18.18 % vs 38.18 %, χ2 = 4.492, P = 0.034], and lung ultrasound scores [4.68 ± 1.60 vs 8.39 ± 1.87, t = 8.383, P < 0.001] in LPVS group were lower than control group. The PEEP, airway pressure and plateau pressure in LPVS group were higher than control group, but driving pressure and tidal volume was lower than control group, the difference was statistically significant (P < 0.05). ConclusionIndividualized PEEP ventilation strategy guided by minimum driving pressure could improve oxygenation and reduce the incidence of PPCs in surgical patients with COVID-19.

Total liquid ventilation in an ovine model of extreme prematurity: a randomized study.

This study aimed at comparing cardiorespiratory stability during total liquid ventilation (TLV)-prior to lung aeration-with conventional mechanical ventilation (CMV) in extremely preterm lambs during the first 6 h of life. 23 lambs (11 females) were born by c-section at 118-120 days of gestational age (term = 147 days) to receive 6 h of TLV or CMV from birth. Lung samples were collected for RNA and histology analyses. The lambs under TLV had higher and more stable arterial oxygen saturation (p = 0.001) and cerebral tissue oxygenation (p = 0.02) than the lambs in the CMV group in the first 10 min of transition to extrauterine life. Although histological assessment of the lungs was similar between the groups, a significant upregulation of IL-1a, IL-6 and IL-8 RNA in the lungs was observed after TLV. Total liquid ventilation allowed for remarkably stable transition to extrauterine life in an extremely preterm lamb model. Refinement of our TLV prototype and ventilation algorithms is underway to address specific challenges in this population, such as minimizing tracheal deformation during the active expiration. Total liquid ventilation allows for remarkably stable transition to extrauterine life in an extremely preterm lamb model. Total liquid ventilation is systematically achievable over the first 6 h of life in the extremely premature lamb model. This study provides additional incentive to pursue further investigation of total liquid ventilation as a transition tool for the most extreme preterm neonates.

Use of venovenous extracorporeal membrane oxygenation in trauma patients with severe adult respiratory distress syndrome: A retrospective study.

The use of extracorporeal membrane oxygenation (ECMO) has increased, although its survival benefit in trauma patients with severe adult respiratory distress syndrome (ARDS) remains controversial. We investigated the effect of veno-venous (VV)-ECMO on the clinical outcomes of trauma patients with severe ARDS. This was a retrospective study at a single center comprising trauma patients admitted between January 2013 and December 2017, diagnosed with severe ARDS using the Berlin definition (PaO2/FiO2 ratio ⩽100), in the 7 days following trauma. Patients were managed with VV-ECMO or conventional mechanical ventilation (CMV). The primary outcome was in-hospital mortality (mortality at 60 days); secondary outcomes comprised 28-day mortality, hospital length of stay (LOS), intensive care unit (ICU) LOS, ICU-free days, duration of mechanical ventilation (MV), and MV-free days. Propensity score matching was performed to adjust for the baseline differences. Sixteen patients (22.5%) were managed with VV-ECMO and 55 were managed with CMV. After matching, the in-hospital mortality rate (43.8% vs 53.1%; p = 0.760), 28-day mortality rate (37.5% vs 31.3%; p = 0.750), median hospital LOS (39.5 vs 36.5 days; p = 0.533), ICU-free days (0 vs 0 days; p = 0.241), and MV-free days (0 vs 0 days; p = 0.272) did not significantly differ between the VV-ECMO and CMV groups. In-hospital mortality (mortality at 60 days) did not differ significantly between the VV-ECMO and CMV groups. Although the safety of ECMO in trauma patients requires further investigation, VV-ECMO may be considered as a rescue therapy.

Effects of Neurally Adjusted Ventilation Assist (NAVA) and conventional modes of mechanical ventilation on diaphragm functions: A randomized controlled trial

BackgroundBetter patient-ventilator interactions, during neurally adjusted ventilator assist (NAVA), are expected to result in lower rate of diaphragm dysfunction. ObjectiveThis study was planned to compare the rate of diaphragm dysfunction between the conventional modes of mechanical ventilation and NAVA. MethodsPatients who were initiated on mechanical ventilation for acute respiratory failure were randomized to continue either conventional mode of mechanical ventilation or switched to NAVA. The rates of diaphragm dysfunction were compared between two groups. ResultsThis study included 46 participants (male 30/46) with a mean age of 58 years. Mean APACHE II and SOFA scores were 15 and 3, respectively. The mean (SD) diaphragm thickness fraction in the conventional mechanical ventilation and NAVA group were 37.12% (18.48) and 39.27% (27.65), respectively. The diaphragm dysfunction was observed in 5 (22.7%) and 8 (34.7%) patients in NAVA and conventional arm, respectively. There was no statistically significant difference between the two groups (p-value = 0.37). Diaphragm excursion was better in the NAVA group as compared with the conventional mechanical ventilation group. Diaphragm thickness and thickness fraction were comparable between two groups. ConclusionSwitching from the conventional mode of mechanical ventilation to NAVA leads to statistically non-significant reduction in the occurrence of diaphragm dysfunction. Adequately powered studies are required to assess the exact role of NAVA on diaphragm functions.

The clinical effects of high-frequency oscillatory ventilation in the treatment of neonatal severe meconium aspiration syndrome complicated with severe acute respiratory distress syndrome

ObjectiveTo explore the efficacy and safety of high-frequency oscillatory ventilation (HFOV) in the treatment of severe meconium aspiration syndrome (MAS) complicated with severe acute respiratory distress syndrome (ARDS).MethodsA total of 65 infants with severe MAS complicated with severe ARDS were included in the study. The clinical efficacy of treatment for the HFOV group (n = 31) and the conventional mechanical ventilation (CMV) group (n = 34) was retrospectively analysed. The partial pressure of oxygen (PaO2), partial pressure of carbon dioxide (PaCO2), PaO2/fraction of inspired oxygen (FiO2), and oxygen index values before and at 6, 12, 24, 48, and 72 h after mechanical ventilation, the mechanical ventilation time, oxygen inhalation time, incidence of complications, and outcomes of the two groups were compared.ResultsAt 6, 12, 24, and 48 h after mechanical ventilation, the PaO2 in the HFOV group was significantly higher than in the CMV group, while the PaCO2 in the HFOV group was significantly lower than in the CMV group (P < 0.05). At 6, 12, 24, 48, and 72 h after mechanical ventilation, PaO2/FiO2 in the HFOV group was significantly higher than in the CMV group, and the OI in the HFOV group was significantly lower than in the CMV group (P < 0.05). Mechanical ventilation time, oxygen inhalation time, and the incidence of air leakage were significantly lower in the HFOV than in the CMV group (P < 0.05).ConclusionsOverall, HFOV can effectively improve lung ventilation and oxygenation function, shorten ventilator treatment time, and reduce the incidence rate of air leakage for neonatal MAS, making it a safe and effective treatment option.

Comparative study between noninvasive positive pressure ventilation and invasive mechanical ventilation in patients with respiratory failure

Abstract Background Noninvasive positive pressure ventilation (NIPPV) has been increasingly used in the management of respiratory failure in intensive care unit (ICU). Aim of the Work is to compare the efficacy and resource consumption of NIPPMV delivered through face mask against invasive mechanical ventilation (IMV) delivered by endotracheal tube in the management of patients with acute respiratory failure (ARF). Patients and Methods This prospective randomized controlled study included 78 adults with acute respiratory failure who were admitted to the intensive care unit. The enrolled patients were randomly allocated to receive either noninvasive ventilation or conventional mechanical ventilation (CMV). Results Severity of illness, measured by the simplified acute physiologic score 3 (SAPS 3), were comparable between the two patient groups with no significant difference between them. Both study groups showed a comparable steady improvement in PaO2:FiO2 values, indicating that NIPPV is as effective as CMV in improving the oxygenation of patients with ARF. The PaCO2 and pH values gradually improved in both groups during the 48 hours of ventilation. 12 hours after ventilation, NIPPMV group showed significantly more improvement in PaCO2 and pH than the CMV group. The respiratory acidosis was corrected in the NIPPV group after 24 hours of ventilation compared with 36 hours in the CMV group. NIPPV in this study was associated with a lower frequency of complications than CMV, including ventilator acquired pneumonia (VAP), sepsis, renal failure, pulmonary embolism, and pancreatitis. However, only VAP showed a statistically significant difference. Patients who underwent NIPPV in this study had lower mortality, and lower ventilation time and length of ICU stay, compared with patients on CMV. Intubation was required for less than a third of patients who initially underwent NIV. Conclusion Based on our study findings, NIPPV appears to be a potentially effective and safe therapeutic modality for managing patients with ARF.

Sequential non-invasive following short-term invasive mechanical ventilation in the treatment of tuberculosis with respiratory failure: a randomized controlled study

BackgroundInvasive and non-invasive mechanical ventilation (MV) have been combined as sequential MV in the treatment of respiratory failure. However, the effectiveness remains unclear. Here, we performed a randomized controlled study to assess the efficacy and safety of sequential MV in the treatment of tuberculosis with respiratory failure.MethodsForty-four tuberculosis patients diagnosed with respiratory failure were randomly divided into sequential MV group (n = 24) and conventional MV group (n = 20). Initially, the patients in both groups received invasive positive pressure ventilation. When the patients' conditions were relieved, the ventilation modality in sequential MV group was switched to oronasal face mask continuous positive airway pressure until weaning.ResultsAfter treatment, the patients in sequential MV group had similar respiratory rate, heart rate, oxygenation index, alveolo-arterial oxygen partial pressure difference (A-aDO2), blood pH, PaCO2 to those in conventional MV group (all P value > 0.05). There was no significant difference in ventilation time and ICU stay between the two groups (P > 0.05), but sequential MV group significantly reduced the time of invasive ventilation (mean difference (MD): − 36.2 h, 95% confidence interval (CI) − 53.6, − 18.8 h, P < 0.001). Sequential MV group also reduced the incidence of ventilator-associated pneumonia (VAP; relative risk (RR): 0.44, 95% CI 0.24, 0.83, P = 0.006) and atelectasis (RR:0.49, 95% CI 0.24,1.00, P = 0.040).ConclusionsSequential MV was effective in treating tuberculosis with respiratory failure. It showed advantages in reducing invasive ventilation time and ventilator-associated adverse events.Registration number for clinical trialChinese Clinical Trial Registry ChiCTR2000032311, April 21st, 2020

High frequency oscillatory ventilation and conventional mechanical ventilation in the treatment of infants with severe respiratory syncytial virus pneumonia: a randomized controlled trial

To compare the clinical efficacy of high frequency oscillatory ventilation (HFOV) and conventional mechanical ventilation (CMV) in the treatment of infants with severe respiratory syncytial virus (RSV) pneumonia. A prospective randomized controlled trial was conducted. The infants with severe RSV pneumonia who received invasive mechanical ventilation admitted to intensive care unit (ICU) of Children's Hospital Affiliated to Capital Institute of Pediatrics from January 2018 to December 2019 were enrolled. According to the order of admission, each infant was assigned to HFOV group or CMV group by random number table. The basic data, pediatric critical score, blood gas analysis, ventilator parameters, oxygenation index [OI, OI = mean airway pressure (Pmean)×fraction of inspired oxygen (FiO2)/arterial partial pressure of oxygen (PaO2)×100], duration of mechanical ventilation, length of ICU stay, complications, prognosis, use of muscle relaxants and vasoactive drugs and other clinical indicators of the two groups were recorded. A total of 28 infants were enrolled in the analysis, including 15 infants receiving CMV and 13 infants receiving HFOV. There were no significant differences in age, body weight, pediatric critical score and OI before enrollment, type II respiratory failure, multiple organ dysfunction, basic diseases and laboratory examination indexes before enrollment between the two groups. Six hours after enrollment, compared with CMV group, heart rate (HR), respiratory rate (RR), case of transcutaneous oxygen saturation (SpO2) decrease, case of HR decrease, case of cardiopulmonary resuscitation (CPR) and OI in HFOV group were significantly decreased [HR (bpm): 130 (125, 138) vs. 144 (140, 160), RR (times/min): 35 (34, 38) vs. 40 (35, 45), SpO2 decrease (case: 1 vs. 10), HR decrease (case: 0 vs. 6), CPR (case: 0 vs. 4), OI: 6.5 (4.4, 8.9) vs. 9.3 (8.0, 12.8)], while case of use of muscle relaxants (case: 3 vs. 0) and volume of 7-day positive fluid balance [mL/kg: 167.1 (113.8, 212.6) vs. 90.8 (57.8, 112.7)] were significantly higher, the differences were statistically significant (all P < 0.05). There was no use of blood purification treatment, no severe complications such as pneumothorax and intracranial hemorrhage, and no death within 28 days in the two groups. Compared with CMV, HFOV in the treatment of infants with severe RSV pneumonia can improve the oxygenation level and clinical physiological indexes earlier, reduce the incidence of adverse events such as HR, SpO2 decrease and CPR, increase the use of muscle relaxants and the positive fluid balance, and do not increase the incidence of severe complications such as pneumothorax and intracranial hemorrhage, so its clinical application is safe.

HFOV vs CMV for neonates with moderate-to-severe perinatal onset acute respiratory distress syndrome (NARDS): a propensity score analysis.

This study aimed to evaluate whether high-frequency oscillatory ventilation (HFOV) could reduce mortality and the incidence of bronchopulmonary dysplasia (BPD) of perinatal-onset neonatal acute respiratory distress syndrome (NARDS) compared with conventional mechanical ventilation (CMV). Medical records were collected and retrospectively analyzed. Among the 700 neonates with NARDS who needed invasive ventilation, 501 (71.6%) received CMV, while 199 (28.4%) received HFOV. One-to-one propensity score matching (127:127) was used to match the baseline characteristics of patients who received CMV and HFOV. The results showed that birth weight and oxygenation index (OI) were independently associated with mortality in the multivariate logistic regression. No significant differences were observed in mortality or the incidence of BPD between the two groups. The incidence of intraventricular hemorrhage (IVH) and ventilation-free days were significantly lower in the HFOV group than in the CMV group (3.9 vs 11.80%, p=0.02; 15.226 vs 20.967 days, p=0.01). There were no significant differences between the two groups regarding other secondary outcomes.Conclusion: HFOV was associated with a decreased incidence of IVH in infants with NARDS compared with CMV. However, there were significantly more VFDs in the CMV group than in the HFOV group, and HFOV did not appear to be superior to CMV in decreasing the mortality and incidence of BPD in infants with NARDS.What is Known:• The diagnostic criteria of neonatal acute respiratory distress syndrome (Montreux criteria) were established in 2017.• To date, studies comparing high-frequency oscillatory ventilation and conventional mechanical ventilation in the treatment of neonatal acute respiratory distress syndrome are insufficient.What is New:• High-frequency oscillatory ventilation did not appear to be superior to conventional mechanical ventilation in decreasing the mortality and incidence of bronchopulmonary dysplasia in infants with moderate-to-severe perinatal-onset neonatal acute respiratory distress syndrome.• High-frequency oscillatory ventilation was associated with a decreased incidence of intraventricular hemorrhage in infants with moderate-to-severe perinatal-onset acute respiratory distress syndrome compared with conventional mechanical ventilation.

ПРИМЕНЕНИЕ ВЫСОКОЧАСТОТНОЙ ИСКУССТВЕННОЙ ВЕНТИЛЯЦИИ ЛЕГКИХ В РОДИЛЬНОМ ЗАЛЕ У НЕДОНОШЕННЫХ НОВОРОЖДЕННЫХ ДЕТЕЙ С РЕСПИРАТОРНЫМ ДИСТРЕСС-СИНДРОМОМ

Objective of the research: comparison of two methods of initial respiratory support: high-frequency positive pressure ventilation (HFPPV) and conventional mechanical ventilation (CMV) in extremely low birth weight (ELBW) infants. Materials and methods: prospective, randomized, pilot study, carried out in one level III perinatal center. Thirty-two ELBW babies was randomly separated in two groups: group A – HFPPV (n=17), group B – CMV (n=15). Results: the recovery time for heart rate more than 100 beats per minute in group A was faster than in group B (33,9 seconds vs. 79,2 seconds, p=0,002). Maximum FiO2 for the period of staying in hospital was significantly higher in group B (0,37 vs. 0,73, p&lt;0,001). Mortality in CMV group was significantly higher (0% versus 27%, p=0,038). Conclusion: HFPPV in the delivery room in ELBW babies effectively restores heart rate, reduces the risk of lungs injury and the risk of death before discharge from the hospital.

Prognosis of conventional vs. high-frequency ventilation for congenital diaphragmatic hernia: a retrospective cohort study.

To determine the appropriate initial ventilatory mode for neonatal congenital diaphragmatic hernia (CDH) by comparing patient prognosis following conventional mechanical ventilation (CMV) versus high-frequency oscillatory ventilation (HFO). This multicenter retrospective cohort study was performed at 15 participating hospitals in Japan between 2011 and 2016. The 328 eligible CDH infants were classified into CMV (n = 78) and HFO groups (n = 250) to compare mortality and incidence of bronchopulmonary dysplasia (BPD). Propensity score matching was applied to reduce confounding by indication. While crude mortality was significantly higher in the HFO than the CMV group, adjusted odds ratio (OR) did not show significant difference in mortality between groups (OR of HFO group: 0.98, 95% confidence interval (CI): 0.57-1.67). Adjusted OR of BPD incidence showed no significant difference between groups (OR of HFO group: 1.66, 95%CI: 0.50-5.49). Initial ventilatory mode in CDH patients, whether CMV or HFO, does not affect prognosis.

Effect of perfluorocarbon partial liquid ventilation-induced hypothermia on dogs with acute lung injury.

Acute lung injury (ALI) is the damage of alveolar epithelial cells and capillary endothelial cells caused by various direct and indirect injury factors, resulting in diffuse pulmonary interstitial and alveolar edema, resulting in acute hypoxic respiratory insufficiency. This study aimed to investigate the effects of hypothermia induced by partial fluid ventilation on dogs with ALI. The experimental dogs were randomly divided into a conventional mechanical ventilation group (CMV) group, a normal temperature perfluorocarbon liquid ventilation group (NPLV) group, and a hypothermic perfluorocarbon liquid ventilation group (HPLV) group. After induction of ALI, the dogs of the CMV group was treated with CMV for respiratory support, the HPLV group was given a 15 °C low-temperature perfluorocarbon partial liquid ventilation (PLV), and the NPLV group was given partial fluid permeation of perfluorocarbon (PFC) at a room temperature of 37 °C. Anesthesia was stable at 0.5 h (T0), and successful modeling (T1), at 1 h (T2), 2 h (T3), 3 h (T4) and 4 h (T5) was completed. Blood gas analysis was performed, and rectum temperature, peak airway pressure (PIP), and lung compliance were measured. We performed enzyme-linked immunosorbent assay (ELISA) for peripheral blood and postoperative bronchoalveolar lavage fluid (BALF), calculation of lung tissue wet weight/dry weight ratio, and Western blot detection of NF-κB p65. In the HPLV group, the blood gas index of dogs with ALI was close to normal. In T2¬-T5, the rectal temperature of the HPLV group was significantly lower than that of the NPLV group and the CMV group the lung compliance in the HPLV group and the NPLV group was lower than that in the CMV group at the T2-T5 time point, while the CLst value was significantly increased. The detection of peripheral blood and BALF in dogs showed that interleukin-10 (IL-10) was significantly increased and TNF-α was significantly decreased in the HPLV group compared with the CMV group and NPLV group. Compared with CMV group, the wet/dry ratio of lung tissue in the BALF of HPLV group was decreased. The results indicate that mild hypothermia caused by partial fluid ventilation can increase oxygenation capacity, oxygen partial pressure, the expression of anti-inflammatory factor IL-10 and improve lung compliance in dogs with ALI.

Marathoners' Breathing Pattern Protects Against Lung Injury by Mechanical Ventilation: An Ex Vivo Study Using Rabbit Lungs.

Breathing during a marathon is often empirically conducted in a so-called "2:2 breathing rhythm," which is based on a four-phase cycle, consisting of the 1st and 2nd inspiratory and the 1st and 2nd expiratory phases. We developed a prototype ventilator that can perform intermittent positive pressure ventilation, mimicking the breathing cycle of the 2:2 breathing rhythm. This mode of ventilation was named the marathoners' breathing rhythm ventilation (MBV). We hypothesized that MBV may have a lung protective effect. We examined the effects of the MBV on the pulmonary pre-edema model in isolated perfused rabbit lungs. The pulmonary pre-edema state was induced using bloodless perfusate with low colloid osmotic pressure. The 14 isolated rabbit lung preparations were randomly divided into the conventional mechanical ventilation (CMV) group and MBV group, (both had an inspiratory/expiratory ratio of 1/1). In the CMV group, seven rabbit lungs were ventilated using the Harvard Ventilator 683 with a tidal volume (TV) of 8 mL/kg, a respiratory rate (RR) of 30 cycles/min, and a positive end-expiratory pressure (PEEP) of 2 cmH2O for 60 min. In the MBV group, seven rabbit lungs were ventilated using the prototype ventilator with a TV of 6 mL/kg, an RR of 30 cycles/min, and a PEEP of 4 cmH2O (first step) and 2 cmH2O (second step) for 60 min. The time allocation of the MBV for one cycle was 0.3 s for each of the 1st and 2nd inspiratory and expiratory phases with 0.2 s of intermittent resting between each phase. Peak airway pressure and lung wet-to-dry ratio after 60 min of ventilation were lower in the MBV group than in the CMV group. MBV was considered to have a lung-protective effect compared to CMV.

Extracorporeal membrane oxygenation versus conventional ventilatory support for patients with acute respiratory distress syndrome

Background Venovenous extracorporeal membrane oxygenation (VV-ECMO) should be considered when conventional mechanical ventilation failed to maintain adequate gas exchange. ECMO improved gas exchange and thus preventing hypoxia and ventilator-induced lung injury. Aim To compare between VV-ECMO and conventional mechanical ventilatory support with protective lung strategy in patients with acute respiratory distress syndrome regarding selection of patients, efficacy, complications, and outcome. Patients and methods We retrospectively studied 83 patients referred for VV-ECMO consideration to ECMO center in the ICU in Chest Disease Hospital in Kuwait between January 2015 and October 2018. We had two groups: ECMO group (N=38) and conventional mechanical ventilation group (control group) (N=45). We excluded from ECMO all patients with contraindication to ECMO. After 7 days, five patients shifted to rescue ECMO owing to worsening of their condition. Clinical, laboratory, ventilator parameters, complications, and survival rate were compared between both groups. Result The clinical, laboratory, and ventilator parameters of the patients on randomization were very bad for both groups. After 5 days, significant improvement was recorded among ECMO group. At the end point of the study, weaning from ECMO was successful in 32 (74.4%) of the 43 patients, whereas in the control group, 28 (70%) patients were weaned successfully. Mortality was nonsignificantly higher in the control group (30 vs. 25.6% for ECMO group). The most common fatal complication among ECMO group was bleeding (63.6%), whereas it was respiratory failure among the control group (75%). Advanced age, long duration of mechanical ventilation before ECMO, immunocompromised state, higher blood lactate level and higher Acute Physiology and Chronic Health Evaluation II score, and the underlying lung disease before ECMO were associated with poor outcome. Conclusion VV-ECMO can be considered as an alternative therapy for patients with severe but potentially reversible acute respiratory distress syndrome when conventional ventilation failed. ECMO reduced the risk of ventilator-induced lung injury. ECMO significantly improved most of the clinical, laboratory, and ventilator parameters within days after ECMO application. ECMO had more favorable outcome and lower rate of mortality but with higher complications.

Partial liquid ventilation–induced mild hypothermia improves the lung function and alleviates the inflammatory response during acute respiratory distress syndrome in canines

Background Acute respiratory distress syndrome (ARDS), which is the severest form of pulmonary injury, is the leading cause of death in critical care. At present, the mortality remains high in ARDS. Partial liquid ventilation (PLV) using perfluorocarbon (PFC) has been proven to improve gas exchange and respiratory dynamics of the lungs during ARDS. However, PLV has not been shown to reduce the mortality of ARDS. Some studies have shown that mild hypothermia therapy can reduce lung injuries in animal models of ARDS by reducing inflammatory cytokine levels in lung tissues. However, hypothermia cannot produce a lung protection effect alone, and it may have a synergistic effect with other protective measures. To explore the possible role of PLV combined with mild hypothermia in the treatment of ARDS, in this study, we used PFC liquid ventilation to induce mild hypothermia in dogs suffering from ARDS and analyzed the effects of PFC liquid ventilation-induced mild hypothermia on the levels of inflammatory factors and lung histopathology in dogs with ARDS. The experimental dogs were randomly divided into conventional mechanical ventilation (CMV), normal temperature PFC liquid ventilation (NPLV), hypothermic PFC liquid ventilation (HPLV), and mechanical ventilation (MV) groups. After induction of ARDS, the CMV group was treated with CMV for respiratory support, the HPLV group was treated with PLV-induced mild hypothermia using 15 °C PFC and maintained the rectal temperature at 34–36 °C, the NPLV group was treated with PLV using 36 °C PFC and maintained the rectal temperature at 36–38 °C. The MV group served as the control group. Analyses of the pulmonary pathology, partial pressure of oxygen in the blood, and lung wet-dry weight ratio (W/T) of each dog revealed that PLV-induced mild hypothermia significantly increased the PaO2 values and attenuated lung injury, and there were no adverse effects on hemodynamics. Furthermore, treatment with PLV-induced mild hypothermia significantly increased the expression of the anti-inflammatory factor IL-10 in bronchoalveolar lavage fluid (BALF) and attenuated the expression of interleukin (IL-6) and tumor necrosis factor-α (TNF-α) in peripheral blood and in lung BALF. Moreover, the results showed that the expression of myeloperoxidase (MPO) and NF-κB p65 in lung tissues was significantly decreased by PLV-induced mild hypothermia compared with NPLV and CMV. Our results indicated that PLV combined with mild hypothermia can provide protection against oleic acid-induced ARDS in dogs.

Effect of flurbiprofen axetil combined with lung-protective ventilation on postoperative cellular immune function in patients undergoing thoracoscopic radical resection of lung cancer

Objective To investigate the effect of flurbiprofen axetil combined with lung-protective ventilation on postoperative cellular immune function in the patients undergoing thoracoscopic radical resection of lung cancer. Methods Eighty American Society of Anesthesiologists physical status Ⅰor Ⅱ patients of both sexes, with no abnormal lung function during the preoperative examination, aged 35-64 yr, with body mass index of 18-28 kg/m2, scheduled for elective thoracoscopic radical resection of lung cancer under general anesthesia, were divided into 4 groups(n=20 each)using a random number table method: conventional mechanical ventilation group(group C), flurbiprofen axetil combined with conventional mechanical ventilation group(group F+ C), lung-protective ventilation group(group P)and flurbiprofen axetil combined with lung-protective ventilation group(group F+ P). Flurbiprofen axetil 2 mg/kg was intravenously injected at 5 min before induction of anaesthesia in F+ C and F+ P groups.Patients were mechanically ventilated in volume-controlled mode in four groups.Conventional ventilator settings were adjusted with tidal volume(VT)10 ml/kg and respiratory rate 10-20 breaths/min during two-lung ventilation and with VT 8 ml/kg and respiratory rate 13-16 breaths/min during one-lung ventilation.Lung-protective ventilator settings were adjusted with VT 8 ml/kg and respiratory rate 12-14 breaths/min during two-lung ventilation and with positive end-expiratory pressure 5 cmH2O, VT 6 ml/kg and respiratory rate 14-16 breaths/min during one-lung ventilation.All patients received patient-controlled intravenous analgesia(PCIA)at the end of surgery until 24 h after surgery.PCIA solution contained sufentanil 100 μg and ondansetron 16 mg in 100 ml of normal saline in group C and group P. PCIA solution contained sufentanil 100 μg, flurbiprofen axetil 2 mg/kg and ondansetron 16 mg in 100 ml of normal saline in group F+ C and group F+ P.The PCIA pump was set up with a 0.5 ml bolus dose, a 15-min lockout interval and background infusion at a rate of 2 ml/h.Visual analog scale score was maintained ≤3.When visual analog scale score >3, tramadol 2 mg/kg was intravenously injected.Before induction of anesthesia(T0), at the end of surgery(T1), at 24 and 72 h after surgery(T2, 3)and at 1 week after surgery(T4), blood samples were collected from the central vein for measurement of the levels of T lymphocyte subsets CD3+ , CD4+ , CD8+ and NK cells.The CD4+ /CD8+ ratio was calculated. Results Compared with the baseline at T0, the levels of CD3+ , CD4+ and NK cells and CD4+ /CD8+ ratio were significantly decreased at T1-3 in C, F+ C and P groups and at T1, 2 in group F+ P(P<0.05). Compared with group C, the levels of CD3+ , CD4+ and NK cells and CD4+ /CD8+ ratio were significantly increased at T1-3 in the other three groups(P<0.05). Compared with group F+ C or group P, the levels of CD3+ , CD4+ and NK cells and CD4+ /CD8+ ratio were significantly increased at T1-3 in group F+ P(P<0.05). Conclusion Flurbiprofen axetil combined with lung-protective ventilation improves postoperative cellular immune function and provides better efficacy than either alone in the patients undergoing thoracoscopic radical resection of lung cancer. Key words: Cyclooxygenase inhibitors; Respiration, artificial; Immunity, cellular; Thoracoscopy

An experiment on the pathogenesis of early biotrauma in ventilator-induced lung injury

To investigate the pathogenesis of early biotrauma in ventilator-induced lung injury (VILI). Twenty-four 8-week-old male specific-pathogen-free Sprague-Dawley (SD) rats weighing 250-300 g were randomly divided into sham group (S group), conventional mechanical ventilation group (L group) and high tidal volume (VT) mechanical ventilation group (H group) with 8 rats in each group. All rats received tracheostomy after anesthesia. Rats in S group received no mechanical ventilation but breathe room air spontaneously. All other parameters of the ventilator were the same in both mechanical ventilation groups, and the fraction of oxygen was set to 0.21, the rats in L group received 7 mL/kg VT, and those in H group received 28 mL/kg VT. Four hours after ventilation all rats were sacrificed and the lung tissues were harvested for wet/dry (W/D) ratio. Pathological injury score was evaluated by hematoxylin and eosin (HE) staining. Transferase-mediated deoxyuridine triphosphate-biotin nick end labeling stain (TUNEL) was performed to count the apoptosis cell in lung epithelial. Western Blot was performed to evaluate hemi-channel protein Pannexin-1 expression in lung homogenate. Bronchoalveolar lavage fluid (BALF) was collected, and the concentration of lactate dehydrogenase (LDH), isoprostane, adenosine triphosphate (ATP) and white cell count in BALF were measured. Yo-pro-1/propidium iodide (PI) double stain was performed to evaluate early apoptosis cell in BALF. There was no significant difference in lung injury between S group and L group. Compared with S group and L group, rats in H group showed significant lung injury, represented as alveolar rupture, inflammatory cell infiltration, interstitial edema and airway epithelial exfoliation, and the lung W/D ratio was increased significantly (5.1±0.2 vs. 4.4±0.2, 4.3±0.4, both P < 0.01), pathological score was significantly increased [4.00 (4.00, 8.00) vs. 1.00 (0, 4.00), 2.00 (0, 4.75), both P < 0.01], the white cell in BALF was significantly increased (×106/L: 2.97±0.46 vs. 1.03±0.26, 0.79±0.19, both P < 0.01), the level of LDH was significantly increased (U/L: 148.6±38.2 vs. 34.4±13.5, 78.6±13.9, both P < 0.01), and the expression of Pannexin-1 in lung homogenate was significantly increased (Pannexin-1/GAPDH: 0.89±0.21 vs. 0.48±0.25, 0.61±0.17, both P < 0.01), the ATP concentration in BALF was also significantly increased (nmol/L: 456.84±148.72 vs. 19.23±13.34, 113.26±57.90, both P < 0.01). There was no significant difference in the apoptosis cell in lung tissue or the apoptosis cell rate, isoprostane level in BALF among the three groups [apoptosis cell in lung (cells/HP): 4.00 (3.00, 5.00) vs. 5.00 (4.00, 6.00), 4.00 (3.25, 6.00); apoptosis cell rate in BALF: (0.57±0.20)% vs. (0.42±0.16)%, (0.58±0.19)%; isoprostane in BALF (μg/L): 3.85±0.46 vs. 3.83±0.60, 3.59±0.69, all P > 0.05]. The early pathogenesis of biotrauma in VILI is related to the release of inflammation mediator via membrane channel after activating by pressure stress, but not apoptosis and lipid peroxidation.

Effects of high-tidal-volume mechanical ventilation on the expression of P2X7 receptor and inflammatory response in lung tissue of rats

Ventilator-induced lung injury is a severe complication mainly caused from mechanical ventilation (MV), associated with the upregulation of inflammation response. The mechanism still remains unclear. This study aims to explore the effects of pathological damage, neutrophil infiltration, expression of P2X7 receptor, and activation of Caspase-1 in lung tissue using a rat model. Sprague Dawley (SD) rats were randomly divided into sham group, conventional MV group, and high-tidal-volume ventilation group and fed with clean water and rat food. The sham group received tracheotomy without MV; conventional MV group was given 7 mL/kg tidal volume ventilation, and high-tidal-volume MV group was given 28 mL/kg tidal volume ventilation. All the rats were sacrificed after 4 h of ventilation or spontaneous breath. Lung wet/dry ratio was measured, and paraffin sections were prepared for pathological injury assessment and immunohistochemistry of P2X7 and myeloperoxidase levels. Lung homogenate was used for Western blot analysis of P2X7 receptor and Caspase-1 levels and real-time polymerase chain reaction (PCR) analysis of P2X7 gene expression level. Compared to sham group and conventional MV group, high-tidal-volume MV led to an increase in lung wet/dry ratio and histology score. High-tidal-volume ventilation also led to chemotaxis of neutrophils. The expression levels of protein and messenger RNA (mRNA) of P2X7 receptor were significantly upregulated. Cleaved-caspase-1 expression was also upregulated. All data provide the evidence that high-tidal-volume MV can lead to lung injury, neutrophils infiltration, and upregulation of cleaved-Caspase-1 level. This result may be related to the upregulation of P2X7 receptor expression.

Effects of high-frequency oscillatory ventilation on brain injury in preterm infants with respiratory distress syndrome

Objective To investigate the association between high-frequency oscillatory ventilation (HFOV) and the incidence of brain injury in premature infants(BIPI) with respiratory distress syndrome (RDS). Methods A total of 136 premature infants who were diagnosed as RDS and treated with mechanical ventilation between January 1, 2014 and June 30, 2016 were enrolled. After stratified by gestational age of 36-34 weeks, 33-32 weeks, 31-28 weeks and ≤27 weeks, the neonates were randomly divided into two groups (68 cases each): conventional mechanical ventilation (CMV) and HFOV groups. Duration of ventilation and changes in blood gas parameters following 24, 48 and 72 hours of ventilation were monitored and compared between the two groups. Incidences of BIPI and complications in the two groups were calculated and their associations with gestational age and birth weight were analyzed. Moreover, incidences of cure rates in the two groups were comparatively analyzed. Independent samples t-test, two-way analysis of variance, Chi-square test or Fisher's exact test was used for statistical analysis. Results (1)Significant difference was observed neither in the perinatal factors (prenatal glucocorticoid usage, and incidences of premature rupture of membrane and gestational diabetes mellitus), nor in the severity of RDS between the two groups (all P>0.05). (2) The average duration of ventilation in the CMV group was higher than that of the HFOV group [(68.4±10.3) vs (64.7±8.5) h, t=2.285, P 0.05). (3) Neither the incidence of hemorrhagic brain injury nor that of non-hemorrhagic brain injury showed any significant difference between the CMV and HFOV groups [36.8% (25/68) vs 39.7% (27/68); 16.2% (11/68) vs 14.7% (10/68), both P>0.05]. The total incidence of BIPI showed no significant difference [44.1%(30/68) vs 45.8%(33/68), χ2=0.266, P=0.606]. The smaller gestational age at birth and the lower birth weight, the higher incidence of BIPI, although no significant difference was shown in the incidence of BIPI when compared among different gestational age groups and different birth weight groups (all P>0.05). (4) The incidence of complications in the CMV group was higher than that in HFOV group [25.0%(17/68) vs 11.8%(8/68), χ2=3.970, P=0.044],while the cure rate of RDS was similar [94.1%(64/68) vs 95.6%(65/68), χ2=0.151, P=0.703]. Conclusions HFOV is a safe and reliable therapy for preterm infants with RDS. Compared with CMV, HFOV can shorten the duration of ventilation and reduce the incidence of complications without increasing the risk of BIPI. However, the cure rate of RDS is not increased by HFOV. Key words: Respiratory distress syndrome, newborn; High-frequency ventilation; Brain injuries; Cerebral hemorrhage; Infant, premature