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Acute lung injury/acute respiratory distress syndrome (ALI/ARDS) is a respiratory disorder with high morbidity and mortality caused by various causes. Exosomes can mediate cell communication through paracrine pathways, transfer proteins, lipids, nucleic acids, etc., and interfere with the biological functions of recipient cells. Various cell-derived exosomes have been reported to play an immunomodulatory role in the ALI/ARDS inflammatory model. This article reviews the mechanism of exosomes involved in immune regulation of ALI/ARDS and possible therapeutic approaches.
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As one of the important means for saving severely burned patients, mechanical ventilation can not only improve the function of important organs such as heart, lung, and kidney, but also stabilize the homeostasis of the body, thus promoting the recovery of patients. Improper use of mechanical ventilation, however, can lead to many complications, among which the ventilator-induced lung injury (VILI) is one of the most common and serious complications, accompanying with a high mortality rate. The target of preventing VILI is to minimize the risk of lung injury caused by mechanical ventilation. This article reviews the pathogenesis, diagnosis, and early prevention and treatment of VILI caused by mechanical ventilation in burned patients.
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Acute lung injury (ALI) is a clinically common critical disease with various treatment methods. Stem cell has drawn great attention for excellent performance in treatment of ALI. However, due to its high apoptosis rate, the further clinical application of stem cell is restricted. Exosomes are a kind of extracellular vesicles secreted by cells, which play important role in injury repair with further research about exosomes. This article reviews current situation, brief introduction to exosomes, repair effects of exosomes on ALI, and the potential signal pathway.
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Objective@#To investigate the effect of recombinant human keratinocyte growth factor 2 (rhKGF-2) on lung tissue of rabbits with severe smoke inhalation injury.@*Methods@#A total of 120 New Zealand rabbits were divided into 5 groups by random number table after being inflicted with severe smoke inhalation injury, with 24 rats in each group. Rabbits in the simple injury group inhaled air, while rabbits in the injury+phosphate buffer solution (PBS) group inhaled 5 mL PBS once daily for 7 d. Rabbits in injury+1 mg/kg rhKGF-2 group, injury+2 mg/kg rhKGF-2 group, and injury+5 mg/kg rhKGF-2 group received aerosol inhalation of 1 mg/kg, 2 mg/kg, and 5 mg/kg rhKGF-2 (all dissolved in 5 mL PBS) once daily for 7 d, respectively. On treatment day 1, 3, 5, and 7, blood samples were taken from the ear central artery of 6 rabbits in each group. After the blood was taken, the rabbits were sacrificed, and the tracheal carina tissue and lung were collected. Blood pH value, arterial oxygen partial pressure (PaO2), arterial blood carbon dioxide pressure (PaCO2), and bicarbonate ion were detected by handheld blood analyzer. The expressions of pulmonary surfactant-associated protein A (SP-A) and vascular endothelial growth factor (VEGF) in lung tissue were detected by Western blotting. Pathomorphology of lung tissue and trachea was observed by hematoxylin-eosin staining. Data were processed with analysis of variance of two-way factorial design and Tukey test.@*Results@#(1) Compared with those in simple injury group, the blood pH values of rabbits in the latter groups on treatment day 1-7 had no obvious change (P>0.05). The PaO2 of rabbits in injury+2 mg/kg rhKGF-2 group on treatment day 5 and 7 were (75.0±2.4) and (71.0±4.5) mmHg (1 mmHg=0.133 kPa), respectively, which were significantly higher than (62.0±6.8) and (63.0±3.0) mmHg in simple injury group (q=4.265, 8.202, P<0.05 or P<0.01). The PaO2 of rabbits in injury+5 mg/kg rhKGF-2 group on treatment day 7 was (82.0±4.9) mmHg, which was significantly higher than that in simple injury group (q=6.234, P<0.01). Compared with that in simple injury group, the PaCO2 of rabbits in injury+2 mg/kg rhKGF-2 group on treatment day 3 was significantly decreased (q=4.876, P<0.01) and significantly increased on treatment day 5 (q=5.562, P<0.01); the PaCO2 of rabbits in injury+5 mg/kg rhKGF-2 group was significantly increased on treatment day 5 and 7 (q=5.013, 4.601, P<0.05 or P<0.01). Compared with that in simple injury group, the serum bicarbonate ion of rabbits in injury+1 mg/kg rhKGF-2 group on treatment day 7 was significantly increased (q=5.142, P<0.01); the serum bicarbonate ion of rabbits in injury+2 mg/kg rhKGF-2 group on treatment day 5 and 7 were significantly increased (q=4.830, 6.934, P<0.01); the serum bicarbonate ion of rabbits in injury+5 mg/kg rhKGF-2 group on treatment day 5 were significantly increased (q=3.973, P<0.05). (2) The expressions of SP-A in lung tissue of rabbits in simple injury group and injury+PBS group in each treatment time point were close (P>0.05). The expressions of SP-A in lung tissue of rabbits in injury+2 mg/kg rhKGF-2 group and injury+5 mg/kg rhKGF-2 group on treatment day 3 were 0.091±0.007 and 0.101±0.009, respectively, significantly higher than 0.069±0.009 in simple injury group (q=10.800, 13.580, P<0.01). The expressions of SP-A in lung tissue of rabbits in injury+1 mg/kg rhKGF-2 group, injury+2 mg/kg rhKGF-2 group, and injury+5 mg/kg rhKGF-2 group on treatment day 5 and 7 were 0.127±0.008, 0.132±0.006, 0.194±0.006, 0.152±0.017, 0.166±0.004, 0.240±0.008, significantly higher than 0.092±0.003 and 0.108±0.005 in simple injury group (q=6.789, 12.340, 17.900, 9.875, 31.480, 40.740, P<0.01). (3) On treatment day 1 and 5, there was no significant difference in the expression of VEGF in lung tissue of rabbits among the 5 groups (P>0.05). Compared with those in simple injury group, the expressions of VEGF in lung tissue of rabbits in injury+2 mg/kg rhKGF-2 group on treatment day 3 and 7 were significantly increased (q=4.243, 8.000, P<0.05 or P<0.01), and the expression of VEGF in lung tissue of rabbits in injury+5 mg/kg rhKGF-2 group on treatment day 7 was significantly increased (q=20.720, P<0.01). (4) On treatment day 1, the injury of rabbits in each group was similar, with a large number of neutrophils infiltrated and abscess formed in the alveolar and interstitial tissue, thickened alveolar septum, some collapsed alveolar and atelectasis; large area of tracheal mucosa was degenerated and necrotic, with a large amount of inflammatory exudates blocking in the cavity. On treatment day 3, the inflammation of lung tissue and trachea in each group were improved, but the inflammation in simple injury group and injury+PBS group was also serious. On treatment day 5, the inflammation in lung tissue and trachea of rabbits in injury+2 mg/kg rhKGF-2 group and injury+5 mg/kg rhKGF-2 group were improved much obviously than those in the other groups. On treatment day 7, the inflammation in lung tissue of rabbits in injury+5 mg/kg rhKGF-2 group alleviated obviously than those in the other groups, most alveoli had no obvious exudative fluid, the alveolar cavity was intact and clear, the local alveolar dilated like a cyst, and the alveolar septum thinning; the improvement of inflammation of trachea was more obvious than the other groups, the tracheal mucosa tended to be more complete, and few neutrophils were infiltrated in the endotracheal cavity.@*Conclusions@#Atomization inhalation of rhKGF-2 can improve the PaO2 level of rabbits with severe smoke inhalation injury, reduce airway inflammation, increase the expression of SP-A and VEGF in lung tissue, thus promoting the repair of lung tissue.
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Objective@#To investigate the effects of non-muscle myosin ⅡA (NMⅡA) silenced bone marrow mesenchymal stem cells (BMSCs) on the lung damage of rats at early stage of smoke inhalation injury.@*Methods@#Forty Sprague-Dawley rats were divided into control, simple injury, NMⅡA-BMSCs, and BMSCs groups according to the completely random method, with 10 rats in each group. Rats in control group inhaled air normally, while rats in the latter 3 groups inhaled smoke to reproduce model of smoke inhalation injury. At 30 min post injury, rats in simple injury group were injected with 1 mL normal saline via caudal vein, and rats in group BMSCs were injected with 1 mL the fifth passage of BMSCs (1×107/mL), and rats in group NMⅡA-BMSCs were injected with 1 mL NMⅡA silenced BMSCs (1×107/mL). At post injury hour (PIH) 24, abdominal aorta blood and right lung of rats in each group were harvested, and then arterial partial pressure of oxygen (PaO2), arterial partial pressure of carbon dioxide (PaCO2), and pH value were detected by blood gas analyzer. Ratio of wet to dry weight of lung was determined by dry-wet weight method. Pathological changes of lung were observed with HE staining. Bronchoalveolar lavage fluid (BALF) were collected, and then tumor necrotic factor-α (TNF-α) and interleukin-10 (IL-10) content of BALF was determined by enzyme-linked immunosorbent assay. Data were processed with one-way analysis of variance, Kruskal-Wallis H test, and least-significant difference test.@*Results@#(1) At PIH 24, compared with those in control group, PaO2 values of rats in simple injury, BMSCs, and NMⅡA-BMSCs groups were obviously decreased (with P values below 0.05), and PaCO2 values were obviously increased (with P values below 0.05). Compared with those in simple injury group, PaO2 values of rats in groups NMⅡA-BMSCs and BMSCs were obviously increased (with P values below 0.05), while PaCO2 values were obviously decreased (with P values below 0.05). PaO2 value of rats in group NMⅡA-BMSCs was obviously increased as compared with that in group BMSCs (P<0.05). The pH value of arterial blood of rats in simple injury group was obviously lower than that in control group (P<0.05). (2) At PIH 24, ratios of wet to dry weight of lung of rats in control, simple injury, BMSCs, and NMⅡA-BMSCs groups were 4.36±0.15, 7.79±0.42, 5.77±0.18, and 5.11±0.20, respectively. Compared with that in control group, ratio of wet to dry weight of lung of rats was obviously increased in the other 3 groups (with P values below 0.05). Compared with that in simple injury group, ratio of wet to dry weight of lung of rats was obviously decreased in groups BMSCs and NMⅡA-BMSCs (with P values below 0.05). Compared with that in group BMSCs, ratio of wet to dry weight of lung of rats in group NMⅡA-BMSCs was obviously decreased (P<0.05). (3) At PIH 24, alveolar structure of rats in control group was complete without abnormality. Compared with those in simple injury group, lung injury and infiltration of inflammatory cells of rats in groups BMSCs and NMⅡA-BMSCs were obviously alleviated, and alveolar structure was relatively complete with no thickening of alveolar wall. (4) At PIH 24, compared with that in control group, TNF-α content of BALF of rats in simple injury and BMSCs groups was obviously increased (with P values below 0.05). Compared with that in simple injury group, TNF-α content of BALF in groups BMSCs and NMⅡA-BMSCs was obviously decreased (with P values below 0.05). Compared with that in control group, IL-10 content of BALF in simple injury, NMⅡA-BMSCs and BMSCs groups were obviously increased (with P values below 0.05). Compared with that in simple injury group, IL-10 content of BALF in groups BMSCs and NMⅡA-BMSCs was obviously increased (with P values below 0.05). Compared with that in group BMSCs, IL-10 content of BALF in group NMⅡA-BMSCs was obviously increased (P<0.05).@*Conclusions@#NMⅡA silenced BMSCs can alleviate lung damage of rats at early stage of smoke inhalation injury, showing better effectiveness than using BMSCs only.
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Silver has received much attention for its great anti-infection effect in wound. With the development of nanotechnology, the advantages of silver nanoparticles have gradually arisen in scientific practice and clinical application due to their large specific surface area etc. In this article, we conclude the antibacterial mechanisms of silver nanoparticles, the factors influencing their antibacterial effects, the methods of improving their performance and safety, and their application in burn treatment.
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<p><b>OBJECTIVE</b>To compare the effects of high frequency oscillatory ventilation (HFOV) combined with incremental positive end-expiratory pressure (IP) and those of pure HFOV on myocardial ischemia and hypoxia and apoptosis of cardiomyocytes in dogs with smoke inhalation injury.</p><p><b>METHODS</b>Twelve healthy male dogs were divided into group HFOV and group HFOV+IP according to the random number table, with 6 dogs in each group. After being treated with conventional mechanical ventilation, dogs in both groups were inflicted with severe smoke inhalation injury, and then they received corresponding ventilation for 8 hours respectively. After treatment, the blood samples were collected from heart to determine the activity of creatine kinase-MB (CK-MB) and lactate dehydrogenase 1 (LDH1) in plasma. The dogs were sacrificed later. Myocardium was obtained for determination of content of TNF-α per gram myocardium by ELISA, apoptotic rate of cardiomyocytes by flow cytometer, degree of hypoxia with HE staining, and qualitative and quantitative expression of actin (denoted as integral absorbance value) with streptavidin-biotin-peroxidase staining. Data were processed with t test. The relationship between the content of TNF-α per gram myocardium and the apoptotic rate of cardiomyocytes was assessed by Spearman linear correlation analysis.</p><p><b>RESULTS</b>(1) After treatment for 8 h, the values of activity of CK-MB and LDH1 in plasma of dogs in group HFOV+IP were respectively (734 ± 70) and (182 ± 15) U/L, which were both lower than those in group HFOV [(831 ± 79) and (203 ± 16) U/L, with t values respectively 2.25 and 2.35, P values below 0.05]. (2) Compared with that in group HFOV [(0.060 ± 0.018) µg], the content of TNF-α per gram myocardium of dogs in group HFOV+IP after treatment for 8 h was decreased significantly [(0.040 ± 0.011) µg, t=2.32, P<0.05]. (3) Compared with that in group HFOV [(33.4 ± 2.2)%], the apoptotic rate of cardiomyocytes of dogs in group HFOV+IP after treatment for 8 h was significantly decreased [(28.2 ± 3.4)%, t=3.15, P<0.05]. There was a positive correlation between the content of TNF-α per gram myocardium and the apoptotic rate of cardiomyocytes (r=0.677, P<0.05). (4) HE staining showed that myocardial fibers of dogs in both groups were arranged in wave shape in different degrees, indicating there was myocardial hypoxia in different degrees. Compared with that of group HFOV, the degree of hypoxia in group HFOV+IP was slighter. (5) The results of immunohistochemical staining showed that there was less loss of actin in myocardial fibers of dogs in group HFOV+IP than in group HFOV. The expression level of actin in myocardium of dogs in group HFOV+IP after treatment for 8 h (194.7 ± 3.1) was obviously higher than that in group HFOV (172.9 ± 2.6, t=13.20, P<0.01).</p><p><b>CONCLUSIONS</b>Compared with pure HFOV, HFOV combined with IP can alleviate the inflammatory reaction in myocardium of dogs, reduce the apoptosis of cardiomyocytes, and ameliorate the myocardial damage due to ischemia and hypoxia.</p>
Subject(s)
Animals , Dogs , Male , Apoptosis , Physiology , Burns, Inhalation , Therapeutics , High-Frequency Ventilation , Hypoxia , Myocardial Ischemia , Myocytes, Cardiac , Positive-Pressure Respiration , Respiration, Artificial , Smoke , Smoke Inhalation Injury , Therapeutics , Treatment Outcome , Tumor Necrosis Factor-alphaABSTRACT
<p><b>OBJECTIVE</b>To study the effects of high frequency oscillatory ventilation (HFOV) with different position on oxygenation and hemodynamics of dogs with severe smoke inhalation injury.</p><p><b>METHODS</b>After being treated with conventional mechanical ventilation, 12 dogs were inflicted with severe smoke inhalation injury and treated by HFOV for 30 min. They were divided into HFOV+prone positioning (PP) group and HFOV+supine positioning (SP) group according to the random number table, with 6 dogs in each group. They received HFOV with corresponding position for 8 hours respectively.</p><p><b>RESULTS</b>of blood gas analysis (pH, PaO₂ and PaCO₂ levels), oxygen index (OI) and hemodynamic parameters [heart rate, mean arterial pressure (MAP), and cardiac output (CO)] were recorded or calculated before injury, immediately after injury, and at post ventilation hour (PVH) 2, 4, 6, 8. Data were processed with analysis of variance of repeated measurement, and LSD- t test.</p><p><b>RESULTS</b>(1) At PVH 8, pH value of dogs in group HFOV+PP was significantly higher than that in group HFOV+SP (t = 3.0571, P < 0.05). Compared with those observed immediately after injury, except for group HFOV+SP at PVH 2 and 4 (with t values respectively 2.066 5 and 1.440 7, P values all above 0.05), the pH values in both groups at other treatment time points were decreased (with t values from 2.449 5 to 3.985 3, P < 0.05 or P < 0.01). At PVH 2, 4, 8, the PaO₂ levels in group HFOV+PP [(131 ± 26), (150 ± 40), (112 ± 30) mmHg, 1 mmHg = 0.133 kPa] were higher than those in group HFOV+SP [(81 ± 15), (96 ± 5), (83 ± 6) mmHg, with t values from 2.366 4 to 4.083 5, P < 0.05 or P < 0.01]. The PaO₂ levels in both groups from PVH 2 to PVH 8 were increased, compared with those observed immediately after injury [(55 ± 15) mmHg in group HFOV+SP and (48 ± 11) mmHg in group HFOV+PP, with t values from 2.473 6 to 7.2310, P < 0.05 or P < 0.01]. No statistically significant differences were observed in PaCO₂ level at each time point between two groups (with t values from 0.661 0 to 2.141 9, P values all above 0.05). No statistically significant differences were observed in PaCO₂ levels from PVH 2 to PVH 8 compared with those observed immediately after injury in both groups (with t values from 0.126 2 to 1.768 3, P values all above 0.05). (2) The OI values in group HFOV+SP were significantly higher than those in group HFOV+PP from PVH 2 to PVH 8 (with t values from 3.091 9 to 3.791 6, P < 0.05 or P < 0.01). The OI values in both groups from PVH 2 to PVH 8 were significantly decreased, compared with those observed immediately after injury (with t values from 2.702 0 to 5.969 3, P < 0.05 or P < 0.01). (3) At PVH 6 and PVH 8, heart rate in group HFOV+PP was significantly higher than that in group HFOV+SP (with t values respectively 4.255 9 and 4.765 9, P values both below 0.01). Compared with that observed immediately after injury, heart rate in group HFOV+PP was significantly decreased (with t values from 3.006 2 to 5.135 5, P < 0.05 or P < 0.01) except for PVH 2 (t = 1.938 2, P > 0.05). However, there was no statistical significant difference at each treatment time point in group HFOV+PP (with t values from 0.786 5 to 1.525 8, P values all above 0.05). There was no statistically significant difference in MAP between two groups at each time point (with t values from 0.045 8 to 1.783 4, P values all above 0.05). Compared with that observed immediately after injury, MAP in group HFOV+SP was significantly decreased at PVH 8 (t = 2.368 3, P < 0.05); MAP in group HFOV+PP was significantly decreased at PVH 2 (t = 3.580 1, P < 0.01). At PVH 2 and 4, the CO values in group HFOV+SP were significantly higher than those in group HFOV+PP (with t values respectively 2.310 3 and 4.526 5, P values both below 0.01). Except for group HFOV+SP at PVH 2 (t = 1.294 1, P > 0.05), CO values at other treatment time points in both groups were significantly lower than that observed immediately after injury (with t values from 2.247 0 to 4.067 8, P < 0.05 or P < 0.01).</p><p><b>CONCLUSIONS</b>HFOV+ PP can improve oxygenation with no obvious CO₂ retention or adverse effect on hemodynamic parameters of dogs with severe smoke inhalation injury. Therefore, it is recommended for clinical application.</p>
Subject(s)
Animals , Dogs , Male , Carbon Dioxide , Blood , Disease Models, Animal , Hemodynamics , High-Frequency Ventilation , Oxygen , Blood , Prone Position , Smoke Inhalation Injury , Therapeutics , Supine PositionABSTRACT
<p><b>OBJECTIVE</b>To observe and compare the effects of two kinds of lung recruitment maneuvers, namely sustained inflation (SI) and incremental positive end-expiratory pressure (PEEP) (IP) on oxygenation, respiratory mechanics, and hemodynamics of dogs with severe smoke inhalation injury.</p><p><b>METHODS</b>After being treated with conventional mechanical ventilation, 12 dogs were inflicted with severe smoke inhalation injury. They were divided into group SI and group IP according to the random number table, with 6 dogs in each group. Dogs in group SI were subjected to continuous positive airway pressure ventilation, with inspiratory pressure of 25 cmH2O (1 cmH2o = 0. 098 kPa), and it was sustained for 20 s. PEEP level in group IP was gradually increased by 5 cmH2O every 5 min up to 25 cmH2O, and then it was decreased by 5 cmH2O every 5 min until reaching 2-3 cmH2O. Then the previous ventilation mode was resumed in both groups for 8 hours. Blood gas analysis (pH value, PaO2, and PaCO2), oxygenation index (OI), respiratory mechanics parameters [peak inspiratory pressure (PIP), mean airway pressure, and dynamic lung compliance], and hemodynamic parameters [heart rate, mean arterial pressure (MAP), pulmonary arterial pressure (PAP), and cardiac output (CO)] were recorded or calculated before injury, immediately after injury, and at post ventilation hour (PVH) 2, 4, 6, 8. Data were processed with analysis of variance of repeated measurement and LSD-t test.</p><p><b>RESULTS</b>(1) At PVH 6 and 8, pH values of dogs in group SI were significantly lower than those in group IP (with t values respectively 2. 431 and 2. 261, P values below 0.05); PaO2 levels in group SI [(87 ± 24), (78 ± 14) mmHg, 1 mmHg =0. 133 kPa] were lower than those in group IP [ (114 ± 18) , (111 ± 17) mmHg, with t values respectively 2. 249 and 3.671, P <0.05 or P <0.01]; OI values in group SI were significantly higher than those in group IP (with t values respectively 2.363 and 5.010, P <0.05 or P <0.01). No significant differences were observed in PaCO2 level within each group or between the two groups (with t values from 0. 119 to 1. 042, P values above 0.05). Compared with those observed immediately after injury, the pH values were significantly lowered (except for dogs in group IP at PVH 6 and 8, with t values from 2.292 to 3.222, P <0.05 or P <0.01), PaO2 levels were significantly elevated (with t values from 4. 443 to 6.315, P <0.05 or P <0.01), and OI values were significantly lowered (with t values from 2.773 to 9.789, P <0.05 orP <0.01) in both groups at all the treatment time points. (2) The PIP level at each time point showed no significant differences between two groups (with t values from 0. 399 to 1. 167, P values above 0. 05). At PVH 4 and 8, the mean airway .pressure values of dogs in group SI were significantly higher than those in group IP (with t values respectively 1.926 and 1. 190, P values below 0.05). At PVH 4, 6, and 8, the dynamic lung compliance levels of dogs in group SI [(9.5 ± 1.9), (12.8 ± 2. 1), (13. 1 ± 1.8) mL/cmH2O] were significantly lower than those in group IP [(11.6 ± 1.2), (15.4 ± 1.8), (14.9 ± 0.8) mL/cmH2O], with t values respectively 2. 289, 2. 303, 2. 238, P values below 0.05. Compared with those observed immediately after injury, PIP and the mean airway pressure values of dogs in two groups were significantly lowered at each treatment time point (with t values from 2. 271 to 7. 436, P <0. 05 or P < 0.01); the dynamic lung compliance levels were significantly elevated in both groups at PVH 6 and 8 (with t values from 2. 207 to 4. 195, P < 0.05 or P <0.01). (3) Heart rate, MAP, and PAP levels at each time point between two groups showed no significant differences (with t values from 0. 001 to 1. 170, P values above 0. 05). At PVH 4, 6, and 8, CO levels in group IP [(0. 6 + 0. 3), (0. 6 + 0. 4), (0. 5 + 0. 7) L/min] were significantly lower than those in group SI [(1.5 0.7), (1.8 + 1.1), (1.6 +0.9) L/min], with t values respectively 3. 028, 2.511, 2.363, P values below 0.05. Compared with that observed immediately after injury, CO level in group IP was significantly lowered at PVH 4, 6, or 8 (with t values respectively 2. 363, 2. 302, 2. 254, P values below 0. 05).</p><p><b>CONCLUSIONS</b>Both lung recruitment maneuvers can effectively improve oxygenation and lung compliance of dogs with severe smoke inhalation injury. IP is more effective in improving lung compliance, while SI shows less impact on the hemodynamic parameters.</p>