Brain protective effect of dexmedetomidine vs propofol for sedation during prolonged mechanical ventilation in non-brain injured patients

BACKGROUND Dexmedetomidine and propofol are two sedatives used for long-term sedation.It remains unclear whether dexmedetomidine provides superior cerebral protection for patients undergoing long-term mechanical ventilation.AIM To compare the neuroprotective effects of dexmedetomidine and propofol for sedation during prolonged mechanical ventilation in patients without brain injury.METHODS Patients who underwent mechanical ventilation for>72 h were randomly assigned to receive sedation with dexmedetomidine or propofol.The Richmond Agitation and Sedation Scale(RASS)was used to evaluate sedation effects,with a target range of-3 to 0.The primary outcomes were serum levels of S100-βand neuron-specific enolase(NSE)every 24 h.The secondary outcomes were remifentanil dosage,the proportion of patients requiring rescue sedation,and the time and frequency of RASS scores within the target range.RESULTS A total of 52 and 63 patients were allocated to the dexmedetomidine group and propofol group,respectively.Baseline data were comparable between groups.No significant differences were identified between groups within the median duration of study drug infusion[52.0(IQR:36.0-73.5)h vs 53.0(IQR:37.0-72.0)h,P=0.958],the median dose of remifentanil[4.5(IQR:4.0-5.0)μg/kg/h vs 4.6(IQR:4.0-5.0)μg/kg/h,P=0.395],the median percentage of time in the target RASS range without rescue sedation[85.6%(IQR:65.8%-96.6%)vs 86.7%(IQR:72.3%-95.3),P=0.592],and the median frequency within the target RASS range without rescue sedation[72.2%(60.8%-91.7%)vs 73.3%(60.0%-100.0%),P=0.880].The proportion of patients in the dexmedetomidine group who required rescue sedation was higher than in the propofol group with statistical significance(69.2%vs 50.8%,P=0.045).Serum S100-βand NSE levels in the propofol group were higher than in the dexmedetomidine group with statistical significance during the first six and five days of mechanical ventilation,respectively(all P<0.05).CONCLUSION Dexmedetomidine demonstrated stronger protective effects on the brain compared to propofol for long-term mechanical ventilation in patients without brain injury.

Driving pressure in mechanical ventilation:A review

Driving pressure(ΔP)is a core therapeutic component of mechanical ventilation(MV).Varying levels ofΔP have been employed during MV depending on the type of underlying pathology and severity of injury.However,ΔP levels have also been shown to closely impact hard endpoints such as mortality.Considering this,conducting an in-depth review ofΔP as a unique,outcome-impacting therapeutic modality is extremely important.There is a need to understand the subtleties involved in making sureΔP levels are optimized to enhance outcomes and minimize harm.We performed this narrative review to further explore the various uses ofΔP,the different parameters that can affect its use,and how outcomes vary in different patient populations at different pressure levels.To better utilizeΔP in MV-requiring patients,additional large-scale clinical studies are needed.

Effect of protective lung ventilation strategy combined with lung recruitment maneuver in patients with acute respiratory distress syndrome (ARDS)

Objective:To evaluate the efficacy and safety of protective lung ventilation strategy combined with lung recruitment maneuver (RM) in the treatment patients with acute respiratory distress syndrome (ARDS).Methods:Totally 74 patients with ARDS admitted to the Department of Intensive Care Unit, Changshu Second People's Hospital in Jiangsu Province between September 2010 and June 2013 were selected and randomly divided into lung recruitment group and non-lung recruitment group, and the initial ventilation solution for both groups was synchronized intermittent mandatory ventilation (SIMV). For RM, SIMV mode (pressure control and pressure support) was adopted. Positive end expiratory pressure (PEEP) was increased by 5 cm H2O every time and maintained for 40-50 s before entering the next increasing period, and the peak airway pressure was kept below 45 cm H2O. After PEEP reached the maximum value, it was gradually reduced by 5 cm H2O every time and finally maintained at 15 cm H2O for 10 min.Results:A total of 74 patients with mean age of (49.0±18.6) years old were enrolled, 36 patients were enrolled in lung recruitment maneuver (RM) group and 38 patients were enrolled into non-lung recruitment maneuver (non-RM) group. 44 were male and accounted for 59.5% of all the patients. For the indicators such as PEEP, pressure support (PS), plateau airway pressure (Pplat), peak airway pressure (Ppeak), vital capacity (VC) and fraction of inspired oxygen (FiO2), no statistical differences in the indicators were found between the RM group and non-RM group on D1, D3 and D7 (P>0.05), except that only FiO2 of RM group on D7 was significantly lower than that of non-RM group (47.2±10.0) vs. (52.2±10.5),P<0.05]. For the indicators of blood gas analysis, including pH, arterial oxygen pressure (PaO2), arterial carbon dioxide pressure (PaCO2) and oxygenation index (PaO2/FiO2), PaO2 and PaO2/FiO2 of RM group were significantly higher than those of non-RM group on D7, and the values were [(90.2±16.1) mmHg vs. (76.4±11.3) mmHg,P<0.05] and [(196.5±40.7) mmHg vs. (151.7±37.3) mmHg,P<0.05] respectively. There was no statistical difference in heart rate (HR), cardiac index (CI), central venous pressure (CVP) or mean arterial pressure (MAP) between RM group and non-RM group on D1, D3 and D7 (P>0.05). 28-day mortality, ICU mortality and in-hospital mortality were 25% vs. 28.9%, 25% vs. 26.3% and 36.1% vs. 39.5% respectively between RM group and non-RM group (allP>0.05).Conclusion:Protective lung ventilation strategy combined with lung recruitment maneuver can improve the indicators such as PaO2, FiO2 and PaO2/FiO2 on D7, but failed to improve the final outcomes such as 28-day mortality, ICU mortality and in-hospital mortality.

Effects of acetylcysteine on micro-inflammation and pulmonary ventilation in chronic obstructive pulmonary disease exacerbation

BACKGROUND Acute exacerbation of chronic obstructive pulmonary disease(AECOPD)is a serious complication of chronic obstructive pulmonary disease,often characterized by increased morbidity and mortality.In traditional Chinese medicine,AECOPD is linked to phlegm-heat and blood-stasis,presenting symptoms like thick sputum,fever,and chest pain.It has been shown that acetylcysteine inhalation in conjunction with conventional therapy significantly reduced inflammatory markers and improved lung function parameters in patients with AECOPD,suggesting that acetylcysteine may be an important adjunctive therapy for patients with phlegm-heat-blood stasis type AECOPD.AIM To investigate the effect of acetylcysteine on microinflammation and lung ventilation in patients with phlegm-heat and blood-stasis-type AECOPD.METHODS One hundred patients with phlegm-heat and blood-stasis-type AECOPD were randomly assigned to two groups.The treatment group received acetylcysteine inhalation(10%solution,5 mL,twice daily)along with conventional therapy,whereas the control group received only conventional therapy.The treatment duration was 14 d.Inflammatory markers(C-reactive protein,interleukin-6,and tumor necrosis factor-alpha)in the serum and sputum as well as lung function parameters(forced expiratory volume in one second,forced vital capacity,and peak expiratory flow)were assessed pre-and post-treatment.Acetylcysteine inhalation led to significant reductions in inflammatory markers and improvements in lung function parameters compared to those in the control group(P<0.05).This suggests that acetylcysteine could serve as an effective adjunct therapy for patients with phlegm-heat and blood-stasis-type AECOPD.RESULTS Acetylcysteine inhalation significantly reduced inflammatory markers in the serum and sputum and improved lung ventilation function parameters in patients with phlegm-heat and blood-stasis type AECOPD compared with the control group.These differences were statistically significant(P<0.05).The study concluded that acetylcysteine inhalation had a positive effect on microinflammation and lung ventilation function in patients with this type of AECOPD,suggesting its potential as an adjuvant therapy for such cases.CONCLUSION Acetylcysteine inhalation demonstrated significant improvements in reducing inflammatory markers in the serum and sputum,as well as enhancing lung ventilation function parameters in patients with phlegm-heat and bloodstasis type AECOPD.These findings suggest that acetylcysteine could serve as a valuable adjuvant therapy for individuals with this specific type of AECOPD,offering benefits for managing microinflammation and optimizing lung function.

A Comparison of Arterial Oxygenation between 60% O2 CPAP and 100% O2 CPAP during One-Lung Ventilation: A Prospective Randomized Controlled Study

Background: One-lung ventilation (OLV) is generally adopted for thoracic surgery. The systemic application of a high fraction of inspiratory oxygen (F1O2) and continuous positive airway pressure (CPAP) to the non-ventilated lung is useful for preventing arterial oxygen desaturation. The adverse effects of elevated F1O2 include oxidative lung injury, resorption atelectasis and coronary and peripheral vasoconstriction. It is preferable to avoid hyperoxemia in patients with complications such as chronic obstructive pulmonary disease, idiopathic pneumonia, and bleomycin-treated lungs. We aimed to determine whether the application of 60% O2 CPAP to the non-ventilated lung is sufficient to provide adequate oxygenation with 60% O2 to the ventilated lung. Methods: A total of 70 patients scheduled to receive elective thoracic surgery requiring OLV were recruited. Left double-lumen tubes were applicable in all surgeries. Patients were randomly allocated to one of two groups, to receive either 60% O2 CPAP (60% CPAP group, n = 35), or 100% O2 CPAP (100% CPAP group, n = 35) at a setting of 2 - 3 cmH2O, applied to the non-ventilated lung. Arterial blood gas analyses were obtained at the following stages: RA, spontaneous breathing under room air (RA);TLV, during total lung ventilation (TLV) prior to the initiation of OLV;T5, 5 min after the initiation of OLV;T15, 15 min after the initiation of OLV;T30, 30 min after the initiation of OLV. Results: The PaO2 value in 60% CPAP group vs. 100% CPAP group at each measurement were as follows: RA (mean [standard deviation: SD], 89.7 [8.2] mmHg vs. 85.8 [11.9] mmHg);TLV (277.9 [52.9] mmHg vs. 269.2 [44.0] mmHg);T5 (191.4 [67.9] mmHg vs. 192.3 [66.0] mmHg);T15 (143.2 [67.3] mmHg vs. 154.7 [60.8] mmHg) and T30 (95.6 [32.0] mmHg vs. 112.5 [36.5] mmHg), respectively. Among the five measurement points, T30 was the only time point at which the 100% CPAP group showed a significantly greater PaO2 value than the 60% CPAP group (p = 0.0495). The SaO2 at T30 in the 100% CPAP group (97.4 [2.0]%) was also significantly greater than that in the 60% CPAP group (96.3 [2.2]%, p = 0.039). No differences were found between the groups regarding changes to the overall PaO2 values (p = 0.44) and SaO2 values (p = 0.23) during the study period. Conclusions: Oxygenation could be safely maintained in relatively healthy patients with 60% O2 OLV and 60% O2 CPAP. The application of 60% O2 CPAP during OLV for patients who are not suited to exposure to high F1O2 may be an alternative form of respiratory management.

Effect of High Frequency Oscillatory Ventilation on EVLW and Lung Capillary Permeability of Piglets with Acute Respiratory Distress Syndrome Caused by Pulmonary and Extrapulmonary Insults

The effect of high frequency oscillatory ventilation（HFOV） at early stage on hemodynamic parameters, extravascular lung water（EVLW）, lung capillary permeability, CC16 and s ICAM-1 in piglets with pulmonary or extrapulmonary acute respiratory distress syndrome（ARDS） was explored. Central vein pressure（CVP） and pulse indicator continuous cardiac output（Pi CCO） were monitored in 12 anesthetized and intubated healthy piglets. Pulmonary ARDS（ARDSp） and extrapulmonary ARDS（ARDSexp） models were respectively established by lung lavage of saline solution and intravenous injection of oleic acid. Then the piglets received HFOV for 4 h. EVLW index（EVLWI）, EVLW/intratroracic blood volume（ITBV） and pulmonary vascular permeability index（PVPI） were measured before and after modeling（T0 and T1）, and T2（1 h）, T3（2 h）, T4（3 h） and T5（4 h） after HFOV. CC16 and s ICAM-1 were also detected at T1 and T5. Results showed at T1, T3, T4 and T5, EVLWI was increased more significantly in ARDSp group than in ARDSexp group（P〈0.05）. The EVLWI in ARDSp group was increased at T1（P=0.008）, and sustained continuously within 2 h（P=0.679, P=0.216）, but decreased at T4（P=0.007） and T5（P=0.037）. The EVLWI in ARDSexp group was also increased at T1（P=0.003）, but significantly decreased at T3（P=0.002） and T4（P=0.019）. PVPI was increased after modeling in both two groups（P=0.004, P=0.012）, but there was no significant change within 4 h（T5） under HFOV in ARDSp group, while PVPI showed the increasing trends at first, then decreased in ARDSexp group after HFOV. The changes of EVLW/ITBV were similar to those of PVPI. No significant differences were found in ΔEVLWI（P=0.13）, ΔPVPI（P=0.28） and ΔEVLW/ITBV between the two groups（P=0.63）. The significant decreases in both CC16 and s ICAM-1 were found in both two groups 4 h after HFOV, but there was no significant difference between the two groups. It was concluded that EVLWI and lung capillary permeability were markedly increased in ARDSp and ARDSexp groups. EVLW could be decreased 4 h after the HFOV treatment. HFOV, EVLW/ITBV and PVPI were increased slightly at first, and then decreased in ARDSexp group, while in ARDSp group no significant difference was found after modeling. No significant differences were found in the decreases in EVLW and lung capillary permeability 4 h after HFOV.

Preemptive mechanical ventilation can block progressive acute lung injury

Mortality from acute respiratory distress syndrome(ARDS) remains unacceptable, approaching 45% in certain high-risk patient populations. Treating fulminant ARDS is currently relegated to supportive care measures only. Thus, the best treatment for ARDS may lie with preventing this syndrome from ever occurring. Clinical studies were examined to determine why ARDS has remained resistant to treatment over the past several decades. In addition, both basic science and clinical studies were examined to determine the impact that early, protective mechanical ventilation may have on preventing the development of ARDS in at-risk patients. Fulminant ARDS is highly resistant to both pharmacologic treatment and methods of mechanical ventilation. However, ARDS is a progressive disease with an early treatment window that can be exploited. In particular, protective mechanical ventilation initiated before the onset of lung injury can prevent the progression to ARDS. Airway pressure release ventilation(APRV) is a novel mechanical ventilation strategy for delivering a protective breath that has been shown to block progressive acute lung injury(ALI) and prevent ALI from progressing to ARDS. ARDS mortality currently remains as high as 45% in some studies. As ARDS is a progressive disease, the key to treatment lies with preventing the disease from ever occurring while it remains subclinical. Early protective mechanical ventilation with APRV appears to offer substantial benefit in this regard and may be the prophylactic treatment of choice for preventing ARDS.

High-flow nasal cannula oxygen therapy and noninvasive ventilation for preventing extubation failure during weaning from mechanical ventilation assessed by lung ultrasound score: A single-center randomized study

BACKGROUND: We sought to demonstrate the superiority of a targeted therapy strategy involving high-flow nasal cannula oxygen(HFNCO_(2)) therapy and noninvasive ventilation(NIV) using lung ultrasound score(LUS) in comparison with standard care among patients in the intensive care unit(ICU) who undergo successful weaning to decrease the incidence of extubation failure at both 48 hours and seven days.METHODS: During the study period, 98 patients were enrolled in the study, including 49 in the control group and 49 in the treatment group. Patients in the control group and patients with an LUS score <14 points(at low risk of extubation failure) in the treatment group were extubated and received standard preventive care without NIV or HFNCO_(2). Patients with an LUS score ≥14 points(at high risk of extubation failure) in the treatment group were extubated with a second review of the therapeutic optimization to identify and address any persisting risk factors for postextubation respiratory distress;patients received HFNCO2 therapy combined with sessions of preventive NIV(4-8 hours per day for 4-8 sessions total) for the first 48 hours after extubation.RESULTS: In the control group, 13 patients had the LUS scores ≥14 points, while 36 patients had scores <14 points. In the treatment group, 16 patients had the LUS scores ≥14 points, while 33 patients had scores <14 points. Among patients with the LUS score ≥14 points, the extubation failure rate within 48 hours was 30.8% in the control group and 12.5% in the treatment group, constituting a statistically significant difference(P<0.05). Conversely, among patients with an LUS score <14 points, 13.9% in the control group and 9.1% in the treatment group experienced extubation failure(P=0.61). The length of ICU stay(9.4±3.1 days vs. 7.2±2.4 days) was significantly different and the re-intubation rate(at 48 hours: 18.4% vs. 10.2%;seven days: 22.4% vs. 12.2%) significantly varied between the two groups(P<0.05). There was no significant difference in the 28-day mortality rate(6.1% vs. 8.2%) between the control and treatment groups.CONCLUSIONS: Among high-risk adults being weaned from mechanical ventilation and assessed by LUS, the NIV+HFNCO_(2) protocol does not lessen the mortality rate but reduce the length of ICU stay, the rate of extubation failure at both 48 hours and seven days.

Effect of Nalmefene on Delayed Neurocognitive Recovery in Elderly Patients Undergoing Video-assisted Thoracic Surgery with One Lung Ventilation

The intravenous use of nalmefene has been found to exert neuroprotective effect in patients with severe traumatic brain injury and acute cerebral infarction;nonetheless,it is unknown whether nalmefene alleviates delayed neurocognitive recovery.Our purpose of the current research was to clarify the impact of nalmefene on delayed neurocognitive recovery in aged patients experiencing video-assisted thoracic surgery(VATS)with intraoperative use of one lung ventilation(OLV).The present study involved 120 paticents undergoing selective VATS,randomized to accept low-dose nalmefene(N1 group,n=40),high-dose nalmefene(N2 group,1n=40)or equal volume of physiologic saline(control group,1=40).A battery of neuropsychological tests were used to estimate cognitive function I day before surgery(o)and 10 days after surgery or before discharge(t).Regional cerebral oxygen saturation(rSO2)was detected 5 min before induction(t),5 min after induction(1),15 and 60 min after onset of OLV(62 and 13),and 15 min after termination of OLV(4).The plasma values of interleukin(IL)-1β,IL-6,tumor necrosis factor(TNF)-a1 and adiponectin(ADP)were also detected prior to induction of anesthesia(T0),1 h,2 h and 6 h after surgery(TI,T2,T3).On 1,delayed neurocognitive recovery occurred in 5/40(12.5%)patients of NI group,in 5/40(12.5%)patients of N2 group and in 13/40(32.5%)patients of control group(P<0.05).There were no statistical differences in rSO2 among three groups at different time points.At Tl,T2 and T3,IL-1β,IL-6 and TNF-a values significantly increased and ADP value significantly decreased(P<0.05)in control group.In contrast,at TI,T2 and T3,IL-1β,IL-6 and TNF-a values decreased and ADP value decreased less in N1 and N2 groups(P<0.05).At TI,T2 and T3,IL-1β,IL-6 and TNF-a concentrations presented a trend of N2 group<N1 group<control group and ADP presented a trend of N2 group>Nl group>control group(P<0.05).The result of our present research supports the hypothesis that the perioperative intravenous treatment with nalmefene to VATS with OLV ameliorates postoperative cognitive function and decreases the incidence of delayed neurocognitive recovery,most likely by suppression of inflammatory responses.

Oxygenation,inflammatory response and lung injury during one lung ventilation in rabbits using inspired oxygen fraction of 0.6 vs.1.0

Maintaining adequate oxygenation during one-lung ventilation（OLV） requires high inspired oxygen fraction（FiO_2）.However,high FiO_2 also causes inflammatory response and lung injury.Therefore,it remains a great interest to clinicians and scientists to optimize the care of patients undergoing OLV.The aim of this study was to determine and compare oxygenation,inflammatory response and lung injury during OLV in rabbits using FiO_2 of 0.6 vs.1.0.After 30 minutes of two-lung ventilation（TLV） as baseline,30 rabbits were randomly assigned to three groups receiving mechanical ventilation for 3 hours：the sham group,receiving TLV with 0.6 FiO_2;the 1.0 FiO_2 group,receiving OLV with 1.0 FiO_2;the 0.6 FiO_2 group,receiving OLV with 0.6 FiO_2.Pulse oximetry was continuously monitored and arterial blood gas analysis was intermittently conducted.Histopathologic study of lung tissues was performed and inflammatory cytokines and the mRNA and protein of nuclear factor kappa B（NF-κB） p65 were determined.Three of the 10 rabbits in the 0.6 FiO_2 group suffered hypoxemia,defined by pulse oximetric saturation（SpO_2） less than 90%.Partial pressure of oxygen（PaO_2）,acute lung injury（ALI） score,myeloperoxidase（MPO）,tumor necrosis factor-a（TNF-α）,interleukin-6（IL-6）,mRNA and protein of NF-kB p65 were lower in the 0.6 FiO_2group than in the 1.0 FiO_2 group.In conclusion,during OLV,if FiO_2 of 0.6 can be tolerated,lung injury associated with high FiO_2 can be minimized.Further study is needed to validate this finding in human subjects.

Expression Changes of Early Response Genes in Lung Due to High Volume Ventilation

The expression changes of early response genes due to ventilation with high volume in adult rats in vivo were observed. Forty SD male rats were randomly divided into control and 30, 60, 90 and 120 min ventilation groups, respectively (n=8 in each group). The animals were ventilated with tidal volume of 42 ml/kg and a PEEP level of 0 cmH_2O at a rate of 40 breaths per minute in room air with a ventilator was given to the small animals. The expression of Egr-1, C-jun and IL-1β mRNA and proteins was detected by RT-PCR and immunohistochemical technique, respectively. The pathological changes in lung tissues were examined by HE staining. The results indicated that the expression of Egr-1, C-jun and IL-1β mRNA was detectable at 30th min after overventilation, but there was no significant difference in comparison with that in control group until overventilation for 60 min. However, at 90 and 120 min there was a significent increase as compared with 30 min or control group (P<0.05). The expression of Egr-1, C-jun and IL-1β deteced by immunohistochemical assay also showed a similar tendency of the gradual increase. In the 120 min ventilation group, the expression intensity of Egr-1, C-jun and IL-1β proteins in lung cells was the strongest and the nuclear translocation was increased markedly in comparison with any other groups (P<0.05). HE staining suggested that the degree of lung injury was aggravated gradually with the ventialtion going on and had a similar tendency to the expression of these early response genes and proteins. The current data suggested that overventilation activated and upregulated the expression of early response genes and the expression of these genes may be taken as the early signal to predict the onset and degree of lung injury. These results may demonstrated partially that the expression of early response genes induced by the mechanical stretch is associated with biochamic lung injury.

Zinc-deficient diet aggravates ventilation-induced lung injury in rats

We investigated the effects of zinc deficiency on acute lung injury （ALI） induced by mechanical ventilation. Male Sprague-Dawley rats were fed with a zinc-deficient or zinc-proficient diet for 4 weeks, and then received mechanical ventilation at normal frequency and pressure for 30 min. Total protein, cell count, the number of poly- morphonuclear neutrophil （PMN） in the bronchoalveolar lavage （BAL）, and vascular endothelial growth factor （VEGF） expression in the lung were determined. Activation of nuclear factor-t^B （NF-~cB） was detected by exam- ining the phosphorylation of NF-kB （pNF-kB p65） and the expression of inhibitor of NF-kB （pI-kBa）. Compared to the controls, total cell count and the number of PMNs were significantly increased to 160% and 140%, respec- tively, in zinc-deficient rats treated with ventilation. Activation of NF-kB was significantly increased and VEGF was also increased to three-folds. Zinc deficiency aggravated the inflammatory response in rats and was associated with the overexpression of VEGF in response to mechanical ventilation. Zinc supplementation may be beneficial to zinc-deficient patients during mechanical ventilation.

Structured Graded Lung Rehabilitation for Children with Mechanical Ventilation

Lung rehabilitation is safe and feasible,and it has positive benefits in weaning the machine as soon as possible,shortening the time of hospitalization and improving the prognosis of children with mechanical ventilation.However,at present,the traditional medical concept is deep-rooted,and doctors'understanding of early rehabilitation is inadequate.It is necessary to make in-depth exploration in the relevant guidelines and expert consensus to formulate standardized early rehabilitation diagnosis and treatment procedures and standards for mechanically ventilated children.In the paper,a structured graded lung rehabilitation program is constructed for children with mechanical ventilation to improve their respiratory function,shorten the time of mechanical ventilation and pediatric intensive care unit(PICU)hospitalization,and reduce their anxiety,based on the principal component analysis of functional pneumonia data.Scientific evaluation and dynamic monitoring ensure the safety of the implementation of the program and promote the prognosis and prognosis of the disease.The proposed lung reha-bilitation program provides a reference basis for the formulation of lung rehabilitation guidelines for children with mechanical ventilation.And It has important reference significance for clinical pulmonary rehabilitation to alleviate the concerns of clinicians and lay the foundation for the large-scale promotion of early lung rehabilitation.

Lung Ventilation Functional Monitoring Based on Electrical Impedance Tomography

Medically, electrical impedance tomography (EIT) is a relatively inexpensive, safe, non-invasive and portable technique compared with computerized tomography (CT) and magnetic resonance imaging (MRI). In this paper, EIT_TJU_Ⅱ system is developed including both the data collection system and image reconstruction algo-rithm. The testing approach of the system performance, including spatial resolution and sensitivity, is described through brine tank experiments. The images of the thorax physical model verify that the system can reconstruct the interior resistivity distribution. Finally, the lung ventilation functional monitoring in vivo is realized by EIT, and the visualized images indicate that the configuration and performance of EIT_TJU_ Ⅱsystem are feasible and EIT is a promising technique in clinical monitoring application.

The Effect of Dexmedetomidine on Oxygenation and Intrapulmonary Shunt during One Lung Ventilation

Background: The effect of intravenously administered dexmedetomidine on oxygenation during one-lung ventilation has not been studied. The hypothesis of this prospective, randomized study was that dexmedetomidine would be associated with an improvement in oxygenation during one-lung ventilation. The secondary outcome was the change in the intrapulmonary shunt. Materials and Methods: Thirty patients undergoing one-lung ventilation were included. Patients in Group D (n = 15) received a bolus dose of 1 μg·kg-1 dexmedetomidine at 10 min after induction of anaesthesia followed by an infusion of 0.4 μg·kg-1·hr-1 that was stopped at the end of the surgery, and those in the control group(Group C, n = 15) were given saline at the same dosage. Vital signs, PaO2, and pulmonary shunting (Qs/Qt) were compared. Results: During one-lung ventilation, the PaO2 in Group D increased significantly and Qs/Qt significantly decreased compared to Group C (PaO2, 203.7 ± 42.3 mmHg vs. 173 ± 37.6 mmHg [P = 0.04] and Qs/Qt 19.8% ± 4.5% vs. 31% ± 2.4% [P < 0.0001], Group D and Group C, respectively). Conclusion: Intravenous administration of dexmedetomidine achieved an improvement in oxygenation during one-lung ventilation. This was associated with a decrease in pulmonary shunt. Use of intraoperative dexmedetomidine during thoracic surgery can be suggested.

Characteristics of Neutrophils Infiltration in Ventilation-induced Lung Injury

Neutrophils play a critical role in ventilation-induced lung injury. This study was aimed to investigate the characteristics of neutrophils influx in lungs induced by high tidal volume ventilation. Anaesthetized rats were randomly divided into low tidal volume ventilation group (Vt: 7 mL/kg, LV group) or high tidal volume ventilation group (Vt:42mL/kg, HV group ) (n=40 in each). Rats in each group were ventilated for 0, 60, 90, 120 and 240 min. The wet/dry lung weight ratio (W/D) was measured. The levels of macrophage inflammatory protein-2 (MIP-2) and tumor necrosis factor-α (TNF-α), and the activity of myeloperoxidase (MPO) were detected by enzyme-linked immunosorbent assay (ELISA). The number of neutrophils in bronchoalveolar lavage fluid (BALF) was counted after Wright’s staining, and the percentage of netrophils in lung tissues calculated. Histopatholgical examination was used to observe the changes of lung tissues after different ventilations. The results showed that the W/D weight ratio was increased, and the levels of MIP-2 and TNF-α significantly enhanced in HV group at 90, 120 and 240 min. Neutrophils in BALF and the neutrophil percentage in lung tissues were also elevated at 120 and 240 min, which coincided with the enhanced activity of MPO in HV group. The lung injury was significantly related with the ventilation time and the infiltration of neutrophils in lungs in HV group. In conclusion, in ventilation-induced lung injury, neutrophil infiltration is present in a time-dependent manner and associated with the aggravated lung injury. Pulmonary structural damage may be the main reason for ventilation-induced lung injury.

Influence of the dexmedetomidine combined with parecoxib sodium on inflammatory factor, blood gas analysis and stress hormone levels in patients undergoing radical resection of esophageal carcinoma during one lung ventilation

Objective: To investigate the effect of dexmedetomidine combined with parecoxib sodium on the levels of inflammatory factors, blood gas analysis and stress hormone in patients undergoing radical resection of esophageal carcinoma during one lung ventilation. Methods:According to the random data table, 81 cases of esophageal cancer patients were divided into the control group (n=41) and observation group (n=40), the patients in the two groups underwent left thoracotomy esophageal cancer radical resection, the control group patients were treated with parecoxib sodium, and patients in the observation group were treated with parecoxib sodium combined with dexmedetomidine medetomidine treatment, before induction of anesthesia (T0), 30 min of one lung ventilation (T1) and 120 min after operation (T2) at three time points, the levels of inflammatory factors [tumor necrosis factor-α (TNF-α), C reactive protein (CRP)], blood gas analysis[oxygen partial pressure (PaO2), carbon dioxide partial pressure (PaCO2)] and stress hormone[epinephrine (E), norepinephrine (NE)] of the two groups were compared. Results: Intra group level comparison, compared with the levels of two groups at the T0 moment, the levels of TNF-α, CRPand NE of theT1 and T2 moment were significantly increased, the level of PaO2 were significantly decreased, and T2 moment levels were significantly higher than that of T1 moment, the difference was statistical significance;There were no significant differences between the two groups of the levels of TNF-α, CRP, PaO2, E and NE of the T0 moment, the levels of TNF-α, CRP, E and NE of the observation group at the T1 and T2 moment were significantly lower than the control group, at the same time the PaO2 level was significantly higher than the control group, the difference was statistically significant;There were no statistically significant differences in PaCO2 levels between groups and at any time. Conclusion: Dexmedetomidine combined with parecoxib sodium can effectively relieve the inflammatory stress, improve the levels of the blood gas analysis index and stress hormone during one lung ventilation, has an important clinical value.

Effect of lung lavage via fiber bronchoscope combined with non-invasive positive pressure ventilation on the blood gas results and systemic state of patients with COPD complicated by severe pneumonia

Objective: To discuss the effect of lung lavage via fiber bronchoscope combined with non-invasive positive pressure ventilation on the blood gas results and systemic state of patients with COPD complicated by severe pneumonia. Methods: A total of 68 patients with COPD complicated by severe pneumonia who were treated in the hospital between November 2015 and April 2017 were collected, retrospectively analyzed and then divided into the group A (n=35) who received noninvasive positive pressure ventilation and the group B (n=33) who received lung lavage via fiber bronchoscope combined with non-invasive positive pressure ventilation. The differences in arterial blood gas and serum index levels were compared between the two groups before and after treatment. Results: Before treatment, there was no statistically significant difference in arterial blood gas index levels as well as serum contents of inflammatory mediators, stress hormones and myocardial enzyme spectrum indexes between the two groups. After treatment, arterial blood gas indexes PH and PaO2 levels of group B were higher than those of group A;serum inflammatory mediators HMGB1, PCT and hs-CRP contents were lower than those of group A;serum stress hormones Cor, AngⅠ and AngⅡcontents were lower than those of group A;serum myocardial enzyme spectrum indexesα-HBDH and cTn-Ⅰ contents were lower than those of group A. Conclusion: Lung lavage via fiber bronchoscope combined with non-invasive positive pressure ventilation can effectively optimize the arterial blood gas levels, reduce systemic inflammatory stress state and protect the myocardial function of patients with COPD complicated by severe pneumonia.

Dimensionless Study on Secretion Clearance of a Pressure Controlled Mechanical Ventilation System with Double Lungs

A pressure controlled mechanical ventilator with an automatic secretion clearance function can improve secretion clearance safely and efficiently.Studies on secretion clearance by pressure controlled systems show that these are suited for clinical applications.However,these studies are based on a single lung electric model and neglect the coupling between the two lungs.The research methods applied are too complex for the analysis of a multi-parameter system.In order to understand the functioning of the human respiratory system,this paper develops a dimensionless mathematical model of doublelung mechanical ventilation system with a secretion clearance function.An experiment is designed to verify the mathematical model through comparison of dimensionless experimental data and dimensionless simulation data.Finally,the coupling between the two lungs is studied,and an orthogonal experiment designed to identify the impact of each parameter on the system.