Effects Of Lung-protective Ventilation Research Articles

Neurological and respiratory effects of lung protective ventilation in acute brain injury patients without lung injury: brain vent, a single centre randomized interventional study

IntroductionLung protective ventilation (LPV) comprising low tidal volume (VT) and high positive end-expiratory pressure (PEEP) may compromise cerebral perfusion in acute brain injury (ABI). In patients with ABI, we investigated whether LPV is associated with increased intracranial pressure (ICP) and/or deranged cerebral autoregulation (CA), brain compensatory reserve and oxygenation.MethodsIn a prospective, crossover study, 30 intubated ABI patients with normal ICP and no lung injury were randomly assigned to receive low VT [6 ml/kg/predicted (pbw)]/at either low (5 cmH2O) or high PEEP (12 cmH2O). Between each intervention, baseline ventilation (VT 9 ml/kg/pbw and PEEP 5 cmH2O) were resumed. The safety limit for interruption of the intervention was ICP above 22 mmHg for more than 5 min. Airway and transpulmonary pressures were continuously monitored to assess respiratory mechanics. We recorded ICP by using external ventricular drainage or a parenchymal probe. CA and brain compensatory reserve were derived from ICP waveform analysis.ResultsWe included 27 patients (intracerebral haemorrhage, traumatic brain injury, subarachnoid haemorrhage), of whom 6 reached the safety limit, which required interruption of at least one intervention. For those without intervention interruption, the ICP change from baseline to “low VT/low PEEP” and “low VT/high PEEP” were 2.2 mmHg and 2.3 mmHg, respectively, and considered clinically non-relevant. None of the interventions affected CA or oxygenation significantly. Interrupted events were associated with high baseline ICP (p < 0.001), low brain compensatory reserve (p < 0.01) and mechanical power (p < 0.05).The transpulmonary driving pressure was 5 ± 2 cmH2O in both interventions. Partial arterial pressure of carbon dioxide was kept in the range 34–36 mmHg by adjusting the respiratory rate, hence, changes in carbon dioxide were not associated with the increase in ICP.ConclusionsThe present study found that most patients did not experience any adverse effects of LPV, neither on ICP nor CA. However, in almost a quarter of patients, the ICP rose above the safety limit for interrupting the interventions. Baseline ICP, brain compensatory reserve, and mechanical power can predict a potentially deleterious effect of LPV and can be used to personalize ventilator settings.Trial registrationNCT03278769. Registered September 12, 2017.Graphical

4: Intra-operative assessment of effects of positive end expiratory pressure compared with zero end-expiratory pressure on atelectasis during surgery under general anaesthesia using ultrasonography: A randomised controlled trial

Background and Aims:Many clinical trials have investigated the use of intraoperative lung protective ventilation to prevent post-operative pulmonary complications. But, few have visually confirmed if protective measures led to decreased intra-operative atelectasis. This study evaluates whether protective ventilation measures reduces peri-operative atelectasis, using ultrasonography.Methods:After obtaining informed consent, 30 patients going through surgery under general anaesthesia were randomly assigned to either lung protective ventilation group (n=15) or zero end expiratory pressure (ZEEP) group (n=15). Lung protective ventilation involved a positive end expiratory pressure (PEEP) of 7cm H2O and recruitment manoeuvres (30cm H2O for 20 seconds) done every 30 minutes during the course of surgery. Lung ultrasound was performed on the patients at four different time points before and after surgery. Lung ultrasound score (LUS) at each time point was then compared between the two groups to analyse the effects of lung protective ventilation on atelectasis.Results:Prior to lung protective ventilation, the LUS was similar between the two groups. Before emergence from general anaesthesia, the mean LUS was lower among patients in the lung protective ventilation group compared to patients in ZEEP group (p<0.05). Lower mean LUS signifies better aeration in lung protective ventilation group before emergence. However, there was no significant difference in mean LUS between the two groups post operatively.Conclusion:Intra-operative lung protective ventilation reduces atelectasis compared to zero end expiratory pressure during surgery as assessed by ultrasound. However, this reduction in aeration loss does not continue in the post-operative period.

Effect of Lung Protective Ventilation Combined With Flurbiprofen Axetil on Immune Function During Thoracoscopic Radical Resection of Lung Cancer.

The decreased immune function of patients with lung cancer has always been the focus of clinical attention. However, the stress response caused by surgery, anesthesia and pain will further reduce the body's immune function and affect the prognosis of patients to a certain extent. It was found that both protective ventilation and flurbiprofen ester pretreatment could reduce the immunosuppression caused by stress response. In this study, 120 lung cancer patients treated with video-assisted thoracoscopic radical resection were divided into group A, group B, group C and group D, which were treated with conventional mechanical ventilation, lung protective ventilation, conventional mechanical ventilation + flurbiprofen axetil and lung protective ventilation + flurbiprofen axetil, respectively. The results showed that the levels of CD3+, CD4+, CD4/CD8+, and NK in groups A, B, and C were lower than T0 on T1, T2, and T3, while those indicators in group D were lower than T0 on T1 and T2 (P < 0.05). The above indicators in group D were higher than those in the other three groups on T1, T2, and T3 (P < 0.05). The above indicators were statistically significant compared with those in group A and group C, group B and group D, and group A and group B at T1, T2, and T3 (P < 0.05). The comparisons of CD3+, CD4+, CD4/CD8+, and NK among the four groups within different time groups, and the repeated - measures analysis of variance (repeated - measures ANOVA) showed that there were interactions among time, group, and between groups × within groups (P < 0.05). It was confirmed that lung protective ventilation combined with flurbiprofen axetil could alleviate the immunosuppression of patients undergoing thoracoscopic radical lung cancer, providing a new idea for clinical treatment.

Hemodynamic, renal and hormonal effects of lung protective ventilation during robot-assisted radical prostatectomy, analysis of secondary outcomes from a randomized controlled trial

BackgroundLung protective ventilation with low tidal volume (TV) and increased positive end-expiratory pressure (PEEP) can have unfavorable effects on the cardiovascular system. We aimed to investigate whether lung protective ventilation has adverse impact on hemodynamic, renal and hormonal variables.MethodsIn this randomized, single-blinded, placebo-controlled study, 24 patients scheduled for robot-assisted radical prostatectomy were included. Patients were equally randomized to receive either ventilation with a TV of 6 ml/IBW and PEEP of 10 cm H2O (LTV-h.PEEP) or ventilation with a TV of 10 ml/IBW and PEEP of 4 cm H2O (HTV-l.PEEP). Before, during and after surgery, hemodynamic variables were measured, and blood and urine samples were collected. Blood samples were analyzed for plasma concentrations of electrolytes and vasoactive hormones. Urine samples were analyzed for excretions of electrolytes and markers of nephrotoxicity.ResultsComparable variables were found among the two groups, except for significantly higher postoperative levels of plasma brain natriuretic peptide (p = 0.033), albumin excretion (p = 0.012) and excretion of epithelial sodium channel (p = 0.045) in the LTV-h.PEEP ventilation group compared to the HTV-l.PEEP ventilation group. In the combined cohort, we found a significant decrease in creatinine clearance (112.0 [83.4;126.7] ml/min at baseline vs. 45.1 [25.4;84.3] ml/min during surgery) and a significant increase in plasma concentrations of renin, angiotensin II, and aldosterone.ConclusionLung protective ventilation was associated with minor adverse hemodynamic and renal effects postoperatively. All patients showed a substantial but transient reduction in renal function accompanied by activation of the renin-angiotensin-aldosterone system.Trial registrationClinicalTrials, NCT02551341. Registered 13 September 2015.

Effect of Lung-Protective Ventilation in Organ Donors on Lung Procurement and Recipient Survival.

Rationale: Previous studies have shown that a lung-protective strategy, which aims at minimizing ventilator-induced lung injury (with low Vt/high positive end-expiratory pressure as the main pillars), in selected potential organ donors after brain death increased lung eligibility and procurement.Objectives: This prospective nationwide cohort study aimed to evaluate the impact of lung-protective ventilation (PV) in nonselected donors on lung procurement and recipient survival after lung transplantation.Methods: We included all reported donors aged 18-70 years after brain death without a lung recovery contraindication and with at least one organ recovered between January 2016 and December 2017. PV was defined as Vt ≤8 ml/kg predicted body weight and positive end-expiratory pressure ≥8 cm H2O. The association between PV at the time of lung proposal (T1) and lung procurement was determined by multivariable logistic regression stratified by propensity score quintile to account for PV and non-PV group differences in baseline characteristics. We studied 1-year survival of recipients from donors with or without PV at T1.Measurements and Main Results: Of 1,626 included lung donors, 1,109 (68%) had at least one lung proposed; 678 (61%) of these had at least one lung recovered. At T1, only 25.6% of donors with at least one lung proposed for lung transplantation were ventilated with a protective strategy. For donors with a lung proposal, the probability of lung procurement was increased with PV at T1 (odds ratio, 1.43; 95% confidence interval [CI], 1.03-1.98; P = 0.03). One-year survival did not differ between recipients of lungs from donors with and without PV (82.7%, 95% CI 76.0-87.8% vs. 82.3%, 95% CI 78.5-85.4%; P = 0.94).Conclusions: The use of lung PV in nonselected donors may increase lung procurement. One-year survival did not differ between recipients of lungs from donors with PV or from those without PV.

Effects of lung protective ventilation on postoperative pulmonary outcomes for prolonged oral cancer combined with free flap surgery.

The intraoperative lung protective ventilation with low tidal volume, positive end expiratory pressure (PEEP) and intermittent lungs recruitment was found to decrease postoperative pulmonary complications. In this retrospective medical records study, we investigated the effects of lung protective ventilation on postoperative pulmonary outcomes among the patients received prolonged oral cancer combined with free flap surgery.We collected the medical records of the patients received oral cancer surgery with the operation time more than 12 hours from January 2011 to December 2015. We recorded1.the patients’ characteristics, past medical history, and laboratory data;2.intraoperative peak airway pressure, fluid intake, urine output, blood loss, and operation duration;3.postoperative PaO2/FiO2 (P/F) ratio when arrived at intensive care unit (ICU), infiltration on Chest X-ray (CXR), duration of ventilator use, ICU stay and hospital stay.Fifty nine cases were included. Thirty cases received the lung protective ventilation and 29 cases received conventional ventilation. Compared to the patients received conventional ventilation, the patients received intraoperative lung protective ventilation showed1.higher postoperative P/F ratio (556.6 ± 115.2) vs 341.9 ± 72.7, P < .001);2.lower incidence of infiltration on postoperative CXR (23.3% vs 51.7%, P = .047);3.shorter duration of ventilator use (6.2 ± 4.5 vs 12.8 ± 7.5 days, P < .001); and4.shorter duration of ICU stay (9.4 ± 5.3 vs 17.1 ± 8.3 days, P < .001).In conclusion, for the prolonged oral cancer combined with free flap surgery, the intraoperative lung protective ventilation improves postoperative pulmonary outcomes and decreases the duration of ICU stay.

Effect of lung protective ventilation on perioperative pulmonary infection in elderly patients with mild to moderate COPD under general anesthesia

ObjectiveThe research aims to explore the effects of different ventilation time on postoperative pulmonary infection in elderly patients with the mild and moderate chronic pulmonary obstructive disease (COPD), so as to provide evidence for reducing postoperative pulmonary infection complications in patients with COPD. Methods120 elderly patients with mild and moderate COPD were selected as the research objects. First, the general information of patients with COPD before surgery and the difference between healthy population and lung forced expiratory volume in 1s (FEV1), forced vital capacity (FVC), FEV1/FVC and maximum midexpiratory flow (MMEF) functional indexes were analyzed and detected. Patients with COPD were operated on with single lung ventilation and general anesthesia. Patients with mild and moderate COPD were divided into two groups according to lung ventilation time (ventilation time 1.0–2.0h group, ventilation time >2.0h group). The inflammatory factors of IL-6, IL-21, TNF-α, and CXCL13 as well as inflammatory indicators of polycaprolactam (PCT), C-reactive protein (CRP) and white blood cell (WBC) in serum of all patients were detected after the operation. The probability of pulmonary infection after COPD was diagnosed and analyzed. Finally, the regression analysis of postoperative pulmonary infection in COPD patients was analyzed. Results(1) The results showed that the smoking rate of mild and COPD patients was significantly higher than that of healthy people (P<0.05). (2) The lung function indexes of the mild and moderate groups were significantly lower than those of the control group (P<0.01), while the lung function indexes of the moderate group were significantly lower than those of the mild group (P<0.05). (3) All the inflammatory indicators of moderate COPD patients were significantly higher than those of mild COPD patients (P<0.05). (4) All inflammation-related indicators in patients with mild and moderate COPD with ventilation time of >2.0h were significantly higher than those in the 1.0–2.0h group (P<0.05). (5) The probability of postoperative pulmonary infection in moderate patients was significantly higher than that in mild patients (P<0.01). The probability of postoperative pulmonary infection in >2.0h group was significantly higher than that in the 1.0–2.0h group (P<0.01). (6) Multivariate Logistic regression analysis results showed that lung function, duration of lung ventilation and smoking were independent risk factors for postoperative pulmonary infection in COPD patients. ConclusionIt is important to detect pulmonary function before surgery, maintain single lung ventilation protection for no more than 2.0h during surgery, and quit smoking to improve pulmonary infection in patients with COPD after surgery. In addition, the incidence of postoperative pulmonary infection in patients with moderate COPD was higher than that in patients with mild COPD, suggesting that early treatment in patients with COPD was also of great significance in reducing the incidence of postoperative pulmonary infection.

The tidal volume fix and more….

In the past 30 years the medical literature has been enriched with numerous publications reporting on randomized clinical trials, meta-analysis and service reviews on invasive ventilation in critically ill patients ( Figure 1 ). For many years the investigations on lung-protective ventilation focused on patients with acute respiratory distress syndrome (ARDS). Interest in the effects of lung-protective ventilation in patients without ARDS is rapidly increasing, however, resulting in a steep rise of the number of publications on lung-protection in patients without ARDS.

A Comparison of the Effects of Lung Protective Ventilation and Conventional Ventilation on Thermoregulation During Anaesthesia.

During prolonged surgery, hypothermia is an unwanted condition that frequently develops and increases complication rates. It has been shown that positive end-expiratory pressure (PEEP) during mechanical ventilation reduces hypothermia development by providing earlier peripheral vasoconstriction. In the present study, an investigation was made of the effect of two different ventilation models on perioperative hypothermia development. A total of 40 patients undergoing elective lumbar disc surgery were randomised to either the conventional group (Group C, n=20, tidal volume=10 mL kg-1, PEEP=0 cm H2O) or the lung protective ventilation group (Group P, n=20, tidal volume=6 mL kg-1, PEEP=5 cm H2O). Demographic data on gender, age, weight, height, preoperative-postoperative temperatures and haemodynamic values were recorded. The point where the forearm to fingertip skin temperature difference reached 0°C was determined as the peripheral vasoconstriction development. At this point, the core temperature was recorded as the thermoregulatory vasoconstriction threshold. Demographic characteristics of the patients and haemodynamic variables were similar between the groups. Preoperative and postoperative temperature gradients were not significantly different between the two groups (p=0.827). There was also no significant difference between the two groups in respect of the vasoconstriction threshold of the patients (p=0.432). The study results showed that lung protective ventilation has no advantage in preserving the perioperative core temperature compared to conventional ventilation.

Effects of Lung Protective Ventilation on the Cognitive Function Level of Patients with Esophageal Cancer

We intended to investigate the effects of lung protective ventilation on the cognitive function level of patients with esophageal cancer. Overall, 132 patients with esophageal cancer admitted to Taian Central Hospital, Taian China from January 2013 to January 2017 were enrolled in the study. According to the random number table method, they were divided into observation group and control group, 66 cases each. All patients underwent general anesthesia for thoracoscopic esophageal cancer radical operation, and lung protective ventilation and conventional positive pressure ventilation were used respectively. The levels of SOD, NSE and MDA, MMSE score and WMS memory quotient in the blood of the elbow vein were compared between the two groups at different times. The levels of SOD and MMSE in the observation group at T2 and T3 were higher than those in the control group, and the NSE and MDA levels were lower than those in the control group (P=0.013, 0.033, 0.015, 0.044, 0.034, 0.029, 0.014, 0.017). The incidence of postoperative cognitive impairment was lower in the observation group than in the control group (P=0.007). The WMS memory quotient scores of the patients in the T2, T3, and T4 observation groups were higher than those in the control group (p=0.009, 0.032, 0.040). Lung protective ventilation can reduce the oxidative stress injury for patients and improve their postoperative cognitive function and memory ability.

Effect of Lung Protective Ventilation in Organ Donors on Lung Procurement and Recipient Survival: Results from a Nationwide Cohort Study

Purpose Previous studies have shown that lung protective strategy in selected potential organ donors after brain death (DBD) increased lung eligibility and procurement. This prospective nationwide cohort study aimed to evaluate the impact of lung protective ventilation (PV) in nonselected DBD upon lung procurement and recipient survival. Methods All reported DBD aged 18-70 years without lung recovery contraindication and with at least one organ recovered between January 2016 and December 2017 were included. Donor characteristics and management were collected at several times until decision on lung offer to transplant teams (t2). PV was defined as tidal volume ≤8 ml/kg of predicted body weight and PEEP≥ 8 cm H2O. The association between PV and lung procurement was determined with multivariable logistic regression stratified by propensity score quintile to account for PV and non PV group differences in baseline characteristics. Survival rates were estimated using Kaplan-Meier method and compared using log-rank test. Results Of the 1,626 included lung donors, 1,109 (68%) had at least one lung offered among whom 678 (61%) had at least one lung recovered. Among donors with lung offered, factors associated with reduced lung procurement were female gender (OR:0.63; 95%CI: 0.43-0.92, p=0.02), age (OR:0.97; 95%CI: 0.96-0.98, p 3 days (OR:0.51 95%CI: 0.38-0.69, p Conclusion The use of lung protective ventilation in nonselected DBD increased probability of lung procurement by 43%. Intermediate analysis suggests that 1-year survival did not differ between recipients of lungs from donors with or without PV.

Lung protective ventilation during pulmonary resection in children: a prospective, single-centre, randomised controlled trial

BackgroundPerioperative ventilatory strategies for lung protection in children are underexplored. This study evaluated the effects of lung protective ventilation (LPV) on postoperative clinical outcomes in children requiring one-lung ventilation (OLV) for pulmonary resection. MethodsChildren age ≤5 yr scheduled for video-assisted thoracoscopic lung lobectomy or segmentectomy were randomly assigned to LPV or control ventilation. For LPV, tidal volume (VT) was 6 ml kg−1 during two-lung ventilation (TLV(VT)), 4 ml kg−1 during OLV, with 6 cm H2O PEEP maintained throughout. In the control group, TLV(VT) was 10 ml kg−1, 8 ml kg−1 during OLV, but without PEEP. The primary outcome was the incidence of pulmonary complications within 72 h after operation. Secondary outcomes included intraoperative desaturation, arterial oxygen partial pressure/inspiratory fraction of oxygen (P/F) ratio >40 kPa, and development of consolidation and B-lines (assessed by lung ultrasound at the end of surgery, by an investigator masked to group allocation). Odds ratio (OR) with 95% confidence intervals are reported. ResultsOverall, 19/110 (17.3%) children sustained pulmonary complications after surgery. LPV reduced pulmonary complications (5/55; 9.1%), compared with 14/55 (25.5%) children sustaining complications in the control group (OR=0.29 [0.10–0.88]; P=0.02). Masked ultrasound assessment showed less consolidation, and fewer B-lines, after LPV (P<0.001). Intraoperative desaturation was more common in control mode (eight/55; 14.5%), compared with 1/55 (1.8%) after LPV (OR=9.2 [1.1–76]; P=0.015). LPV maintained (P/F) ratio >40 more frequently (53/55; 96.4%) than control-mode (45/55; 81.8%) ventilation (OR=5.9 [1.2–28.3%]; P<0.01). ConclusionsLung protective ventilation decreased postoperative pulmonary complications compared with conventional ventilation in children requiring one-lung ventilation for pulmonary resection. Clinical trial registrationNCT02680925.

Effect of lung protective ventilation on coronary heart disease patients undergoing lung cancer resection

Mechanical ventilation, especially large tidal volume (Vt) one-lung ventilation (OLV), can cause ventilator-induced lung injury (VILI) that can stimulate cytokines. Meanwhile, cytokines are considered very important factor influencing coronary heart disease (CHD) patient prognosis. So minimization of pulmonary inflammatory responses by reduction of cytokine levels for CHD undergoing lung resection during OLV should be a priority. Because previous studies have demonstrated that lung-protective ventilation (LPV) reduced lung inflammation, this ventilation approach was studied for CHD patients undergoing lung resection here to evaluate the effects of LPV on pulmonary inflammatory responses. This is a single center, randomized controlled trial. Primary endpoint of the study are plasma concentrations of tumor necrosis factor-α (TNF-α), interleukin (IL)-6, IL-10 and C-reactive protein (CRP). Secondary endpoints include respiratory variables and hemodynamic variables. 60 CHD patients undergoing video-assisted thoracoscopic lung resection were randomly divided into conventional ventilation group [10 mL/kg Vt and 0 cmH2O positive end-expiratory pressure (PEEP), C group] and protective ventilation group (6 mL/kg Vt and 6 cmH2O PEEP, P group; 30 patients/group). Hemodynamic variables, peak inspiratory pressure (Ppeak), dynamic compliance (Cdyn), arterial oxygen tension (PaO2) and arterial carbon dioxide tension (PaCO2) were recorded as test data at three time points: T1-endotracheal intubation for two-lung ventilation (TLV) when breathing and hemodynamics were stable; T2-after TLV was substituted with OLV when breathing and hemodynamics were stable; T3-OLV was substituted with TLV at the end of surgery when breathing and hemodynamics were stable. The concentrations of TNF-α, IL-6, IL-10 and CRP in patients' blood in both groups at the very beginning of OLV (beginning of OLV) and the end moment of the surgery (end of surgery) were measured. The P group exhibited greater PaO2, higher Cdyn and lower Ppeak than the C group at T2, T3 (P<0.05). At the end moment of the surgery, although the P group tended to exhibit higher TNF-α and IL-10 values than the C group, the differences did not reach statistical significance(P=0.0817, P=0.0635). Compared with C group at the end moment of the surgery, IL-6 and CRP were lower in P group, the differences were statistically significant (P=0.0093, P=0.0005). There were no significant differences in hemodynamic variables between the two groups (P>0.05). LPV can effectively reduce the airway pressure, improve Cdyn and PaO2, reduce concentrations of IL-6 and CRP during lung resection of CHD patients.Trial registration: The trial was registered in the Chinese Clinical Trial Registry.

Effect of Lung Protective Ventilation on Lung Procurement in a Real-life Setting

Effect of Lung Protective Ventilation on Lung Procurement in a Real-life Setting

Lung-protective effect of lung-protective ventilation combined with pressure-controlled ventilation-volume guaranteed in elderly patients undergoing one-lung ventilation

Objective To evaluate the lung-protective effect of lung-protective ventilation(LPV)combined with ventilatory mode pressure-controlled ventilation-volume guaranteed(PCV-VG)in elderly patients undergoing one-lung ventilation(OLV). Methods Eighty American Society of Anesthesiologists physical statusⅠ-Ⅲ patients, aged 65-80 yr, with body mass index of 15-28 kg/m2, scheduled for elective radical resection for esophageal cancer performed via video-assisted thoracoscope, were divided into 4 groups(n=20 each)using a random number table: control group(group C), PCV-VG group, LPV group and LPV combined with PCV-VG group(group LPV+ PCV-VG). At 20 min after changing the body position during two-lung ventilation(T1), 30 min of OLV(T2)and 20 min after restoration of two-lung ventilation(T3), blood samples were collected from the radial artery for blood gas analysis and for determination of peak airway pressure(Ppeak), mean airway pressure(Pmean)and dynamic lung compliance(Cdyn). Alveolar-arterial oxygen gradient, intrapulmonary shunt(Qs/Qt), dead space fraction(Vd/VT)and respiratory index were calculated at T2.Blood samples were collected from the radial artery before induction of anesthesia and at the end of operation for determination of plasma neutrophil elastase(NE)concentrations by enzyme-linked immunosorbent assay.The Clinical Pulmonary Infection Score(CPIS)was assessed at 1 and 7 days after operation, and the development of pulmonary complications such as respiratory failure, pulmonary atelectasis and pulmonary infection was recorded within 7 days after operation. Results Compared with group C, Ppeak was significantly decreased, and Pmean was increased in group PCV-VG, Ppeak and PaCO2 were significantly increased and pH value, Vd/VT and Qs/Qt were decreased in group LPV, Ppeak, Vd/VT, Qs/Qt, pH value and postoperative CPIS were significantly decreased, and Pmean, Cdyn and PaO2 were increased in group LPV+ PCV-VG, and the NE concentration at the end of operation was significantly decreased in PCV-VG, LPV and LPV+ PCV-VG groups(P<0.05). Compared with group PCV-VG, Pmean, Cdyn and PaO2 were significantly increased, and pH value, Qs/Qt, NE concentration at the end of operation and CPIS were decreased in group LPV+ PCV-VG(P<0.05). Compared with group LPV, Ppeak, Qs/Qt, NE concentration at the end of operation and CPIS were significantly decreased, and Cdyn was increased in group LPV+ PCV-VG(P<0.05). Pulmonary complications such as respiratory failure, pulmonary atelectasis and pulmonary infection were not observed after operation in the four groups. Conclusion LPV combined with PCV-VG can optimize the lung-protective effect in elderly patients undergoing OLV. Key words: Respiration, artificial; Aged

Effect of lung-protective ventilation on acute lung injury after liver transplantation

Objective To evaluate the effects of lung-protective ventilation on acute lung injury after liver transplantation. Methods Sixty patients of both sexes, aged 21-64 yr, with body mass index of 18-28 kg/m2, of American Society of Anesthesiologists physical status Ⅱ-Ⅳ, scheduled for elective orthotopic liver transplantation, were divided into 2 groups(n=30 each)using a random number table: conventional mechanical ventilation group(group CMV)and lung-protective ventilation group(group LPV). In group LPV, the patients were mechanically ventilated(tidal volume 6-8 ml/kg, respiratory rate 10-15 breaths/min, positive end-expiratory pressure 3-10 cmH2O), and lung recruitment maneuver was performed every 2 h. Before skin incision(T1), at 3 h of preanhepatic phase(T2), at 30 min of anhepatic phase(T3)and at 2 and 4 h of neohepatic phase(T4, 5), bronchoalveolar lavage fluid(BALF)was collected and blood samples from the radial artery were simultaneously collected for determination of tumor necrosis factor-alpha and interleukin-8 concentrations in BALF and serum by enzyme-linked immunosorbent assay.At 2 h after operation(T6), before tracheal extubation(T7)and at 2 days after operation(T8), blood samples from the radial artery were collected for blood gas analysis, and oxygenation index was calculated.The concentrations of serum Clara cell secretory protein 16, surfactant protein D and soluble receptor for advanced glycation end-products were determined at T1-T8 using enzyme-linked immunosorbent assay.The postoperative emergence time, extubation time, duration of intensive care unit stay and development of acute lung injury were recorded. Results Compared with group CMV, the extubation time was significantly shortened, serum concentrations of Clara cell secretory protein 16 at T2, T3, T6 and T7, serum surfactant protein D concentrations at T5 and serum concentrations of soluable receptor for advanced glycation end-products at T5 and T6 were decreased(P 0.05). Conclusion Although lung-protective ventilation dose not decrease the development of acute lung injury after liver transplantation, it attenuates lung tissue injury to some extent. Key words: Respiration, artificial; Respiratory distress syndrome, adult; Liver transplantation

Effects of lung protective ventilation on pulmonary function, inflammation, and oxidative stress in patients undergoing craniotomy: study protocol for a multi-center, randomized, parallel, controlled trial

Background: Conventional mechanical ventilation often leads to lung inflammatory responses and oxidative stress, influencing a patient's prognosis. Lung protective ventilation has been widely used during one-lung ventilation and abdominal surgeries as it can reduce lung tissue injury and improve systemic oxygenation. However, there are few reports on its use during craniotomy. Methods/Design: This multi-center, randomized, parallel, controlled trial will be performed at Anhui Provincial Hospital (Southern District), and the Renmin Hospital of Wuhan University, China. Sixty patients scheduled to undergo craniotomy and meeting our eligibility criteria will be randomly allocated to undergo either lung protective ventilation (6 mL/kg tidal volume, 10 cmH 2 O positive end-expiratory pressure, respiratory frequency 15 breaths/min; n = 30) or conventional mechanical ventilation (10 mL/kg tidal volume, respiratory frequency 12 breaths/min; n = 30). All patients will be evaluated from just prior to surgery (at changing of the ventilation mode) to immediately after extubation. The primary outcome measure will be dynamic lung compliance. The secondary outcome measures will be respiratory index, mean airway pressure, plateau pressure, alveolar and plasma markers of inflammation, and oxidative stress. Discussion: The outcomes will reveal the effects of a protective ventilation strategy using low tidal volumes and the use of positive end-expiratory pressure on respiratory status, postoperative pulmonary and systemic inflammation, and oxidative stress in patients undergoing craniotomy. This will provide objective evidence for the safety of protective ventilation during craniotomy. Trial registration: This trial was registered at Chinese Clinical Trial Registry (registration number: ChiCTR-IPR-16008029) on 1 March 2016. Ethics: The study protocol was approved by the Ethics Committee of Anhui Provincial Hospital, China (approval number: 2014-59) on 27 November 2014 and will be performed in accordance with the guidelines of the Declaration of Helsinki, formulated by the World Medical Association. Informed consent: Written informed consent will be obtained from participants or their guardians.

Protective effects of lung protective ventilation on lungs in patients undergoing radical resection for esophageal cancer

Objective To evaluate the protective effects of lung protective ventilation on the lungs in patients undergoing radical resection for esophageal cancer. Methods Sixty-eight patients of both sexes, aged 40-64 yr, of ASA physical status Ⅰ or Ⅱ, with body mass index 17-40 kg/m2, scheduled for elective radical resection for esophageal cancer, were randomly divided into conventional ventilation group (CV group, n = 34) and protective ventilation group (PV group, n = 34) using a random number table.Double lumen tube was inserted after induction of anesthesia, an anesthesia machine was connected, and the patients were mechanically ventilated.In group CV, VT was set at 10 ml/kg during two-lung ventilation, and VT was set at 7 ml/kg, and I∶E was set at 1∶2 during one-lung ventilation.In group PV, VT was set at 7 ml/kg during two-lung ventilation, VT was set at 5 ml/kg, I∶E was set at 1∶2, and PEEP was set at 10 cmH2O during one-lung ventilation, and bilateral lung recruitment maneuver was performed every 45 min.Before induction of anesthesia, and at days 1, 3, and 5 after surgery, blood gas analysis was performed, and Clinical Pulmonary Infection Score was recorded.Before induction of anesthesia, and at 5 days after surgery, point-of-care testing for pulmonary function was performed, and percentages of maximum ventilatory volume (MVV%), forced vital capacity (FVC%), and forced expiratory volume in 1 second (FEV1%) were recorded, and FEV1/FVC was calculated.The development of respiratory failure, pulmonary atelectasis and incision infection was recorded within 5 min after surgery. Results Compared with group CV, MVV%, FVC%, FEV1% and FEV1/FVC were significantly increased, Clinical Pulmonary Infection Score was decreased at each time point after surgery, SaO2 and PaO2 were increased, and no significant changes were found in pulmonary atelectasis and incision infection in group PV. Conclusion Lung protective ventilation can effectively protect the lungs in the patients undergoing radical resection for esophageal cancer. Key words: Respiration, artificial; Esophageal neoplasms; Esophagectomy

Effect of lung-protective ventilation with lower tidal volumes on clinical outcomes among patients undergoing surgery: a meta-analysis of randomized controlled trials.

In anesthetized patients undergoing surgery, the role of lung-protective ventilation with lower tidal volumes is unclear. We performed a meta-analysis of randomized controlled trials (RCTs) to evaluate the effect of this ventilation strategy on postoperative outcomes. We searched electronic databases from inception through September 2014. We included RCTs that compared protective ventilation with lower tidal volumes and conventional ventilation with higher tidal volumes in anesthetized adults undergoing surgery. We pooled outcomes using a random-effects model. The primary outcome measures were lung injury and pulmonary infection. We included 19 trials (n=1348). Compared with patients in the control group, those who received lung-protective ventilation had a decreased risk of lung injury (risk ratio [RR] 0.36, 95% confidence interval [CI] 0.17 to 0.78; I2=0%) and pulmonary infection (RR 0.46, 95% CI 0.26 to 0.83; I2=8%), and higher levels of arterial partial pressure of carbon dioxide (standardized mean difference 0.47, 95% CI 0.18 to 0.75; I2=65%). No significant differences were observed between the patient groups in atelectasis, mortality, length of hospital stay, length of stay in the intensive care unit or the ratio of arterial partial pressure of oxygen to fraction of inspired oxygen. Anesthetized patients who received ventilation with lower tidal volumes during surgery had a lower risk of lung injury and pulmonary infection than those given conventional ventilation with higher tidal volumes. Implementation of a lung-protective ventilation strategy with lower tidal volumes may lower the incidence of these outcomes.

Carbon Dioxide Clearance in Critical Care

Lung protective ventilation limiting tidal volumes and airway pressures were proven to reduce mortality in patients with acute severe respiratory failure. Hypercapnia and hypercapnic acidosis is often noted with lung protective ventilation. While the protective effects of lung protective ventilation are well recognised, the role of hypercapnia and hypercapnic acidosis remains debatable. Some clinicians argue that hypercapnia and hypercapnic acidosis protect the lungs and may be associated with improved outcomes. To the contrary, some clinicians do not tolerate hypercapnic acidosis and use various techniques including extracorporeal carbon dioxide elimination to treat hypercapnia and acidosis. This review aims at defining the effects of hypercapnia and hypercapnic acidosis with a focus on the pros and cons of clearing carbon dioxide and the modalities that may enhance carbon dioxide clearance.