BACKGROUND Laparoscopic-assisted radical gastrectomy(LARG)is the standard treatment for early-stage gastric carcinoma(GC).However,the negative impact of this proce-dure on respiratory function requires the optimized i...BACKGROUND Laparoscopic-assisted radical gastrectomy(LARG)is the standard treatment for early-stage gastric carcinoma(GC).However,the negative impact of this proce-dure on respiratory function requires the optimized intraoperative management of patients in terms of ventilation.AIM To investigate the influence of pressure-controlled ventilation volume-guaranteed(PCV-VG)and volume-controlled ventilation(VCV)on blood gas analysis and pulmonary ventilation in patients undergoing LARG for GC based on the lung ultrasound score(LUS).METHODS The study included 103 patients with GC undergoing LARG from May 2020 to May 2023,with 52 cases undergoing PCV-VG(research group)and 51 cases undergoing VCV(control group).LUS were recorded at the time of entering the operating room(T0),20 minutes after anesthesia with endotracheal intubation(T1),30 minutes after artificial pneumoperitoneum(PP)establishment(T2),and 15 minutes after endotracheal tube removal(T5).For blood gas analysis,arterial partial pressure of oxygen(PaO_(2))and partial pressure of carbon dioxide(PaCO_(2))were observed.Peak airway pressure(P_(peak)),plateau pressure(Pplat),mean airway pressure(P_(mean)),and dynamic pulmonary compliance(C_(dyn))were recorded at T1 and T2,1 hour after PP establishment(T3),and at the end of the operation(T4).Postoperative pulmonary complications(PPCs)were recorded.Pre-and postoperative serum interleukin(IL)-1β,IL-6,and tumor necrosis factor-α(TNF-α)were measured by enzyme-linked immunosorbent assay.RESULTS Compared with those at T0,the whole,anterior,lateral,posterior,upper,lower,left,and right lung LUS of the research group were significantly reduced at T1,T2,and T5;in the control group,the LUS of the whole and partial lung regions(posterior,lower,and right lung)decreased significantly at T2,while at T5,the LUS of the whole and some regions(lateral,lower,and left lung)increased significantly.In comparison with the control group,the whole and regional LUS of the research group were reduced at T1,T2,and T5,with an increase in PaO_(2),decrease in PaCO_(2),reduction in P_(peak) at T1 to T4,increase in P_(mean) and C_(dyn),and decrease in Pplat at T4,all significant.The research group showed a significantly lower incidence of PPCs than the control group within 3 days postoperatively.Postoperative IL-1β,IL-6,and TNF-αsignificantly increased in both groups,with even higher levels in the control group.CONCLUSION LUS can indicate intraoperative non-uniformity and postural changes in pulmonary ventilation under PCV-VG and VCV.Under the lung protective ventilation strategy,the PCV-VG mode more significantly improved intraop-erative lung ventilation in patients undergoing LARG for GC and reduced lung injury-related cytokine production,thereby alleviating lung injury.展开更多
In order to study the effects of ventilation modes and outlet height on the airflow field of a nursery piggery,computational fluid dynamics (CFD) technology was used to simulate the wind speed and temperature of an ex...In order to study the effects of ventilation modes and outlet height on the airflow field of a nursery piggery,computational fluid dynamics (CFD) technology was used to simulate the wind speed and temperature of an experimental pig house in the cold northern region.This study was conducted with simulation and a comparative analysis of transverse ventilation,longitudinal ventilation and roof air intake modes.Furthermore,the effects of the air outlet height of 0.7,0.6 and 0.5 m with the roof air inlet mode on the environment in the pig house were studied.Field experiments verified the model of roof air intake model.The results showed inadequate ventilation in both the vertical and horizontal ventilation.However,the airfield gradients were less variable and more balanced when using the rooftop air intake mode.The variation of outlet height significantly affected nursery pig houses’ airflow velocity and temperature.Roof air inlet mode with an outlet height of 0.7 m was better than the other two.The normalized mean square error (NMSE) of air velocity and temperature was less than 0.01,and the simulation analysis could genuinely reflect the distribution of the airflow field in the nursery.展开更多
The 1/15 reduced-scale experiments using Froude scaling were designed to study the effect on the smoke control efficiency for subway tunnel fires with natural ventilation mode.The propane gas fires with heat release r...The 1/15 reduced-scale experiments using Froude scaling were designed to study the effect on the smoke control efficiency for subway tunnel fires with natural ventilation mode.The propane gas fires with heat release rate 11.48 kW was used,which corresponds to the heat release rate 10 MW in the full-scale tunnel.The temperature distributions under the ceiling were measured by K-type thermocouples to investigate smoke movement,and the velocity of smoke in shafts was measured by hot-wire anemometer to obtain the smoke extract amount of ventilation shafts.The results show that the smoke temperature under the ceiling varies with the longitudinal different distance from fire source.The results also show that the smoke temperature distributions and the smoke control efficiency in tunnel vary with the space between ventilation shafts and vary with the area and the height of ventilation shaft.展开更多
Making the use of ventilation technology may decrease building energy consumption,improve indoor thermal environment,and ameliorate indoor air quality. Combining with the meteorological characteristics in the Changjia...Making the use of ventilation technology may decrease building energy consumption,improve indoor thermal environment,and ameliorate indoor air quality. Combining with the meteorological characteristics in the Changjiang river valley and focusing on Chongqing,this work makes an applied analysis of the feasibility of intermittent mechanical ventilation. By comparison of various ventilation modes,it gives a summary of the suitable ventilation ways for different weather conditions with the combination of testing data and experimental data.展开更多
Indoor air environment includes indoor thermal environment and air quality, and a reasonable ventilation provides guarantee for a good indoor environment. A numerical study of the indoor environment in different venti...Indoor air environment includes indoor thermal environment and air quality, and a reasonable ventilation provides guarantee for a good indoor environment. A numerical study of the indoor environment in different ventilation is presented in this paper. The External Energy Saving Lab of the WenYuan Building was selected for this purpose, and its indoor air quality and thermal performance in the typical summer climate were simulated. For the numerical simulation, the techniques of Fluent Air-pak was adopted to establish the physical and numerical model of lab. A attention is given to the velocity field and the distribution of pollutant concentration, followed by a discussion of two ventilation modes (displacement ventilation and up-in and up-out ventilation). By comparison, it is found that the Displacement ventilation in improving indoor air quality is obviously superior to the traditional up-in and up-out ventilation.展开更多
Factors contributing to ventilation quantity of the vehicle are ventilation modes, cabin characteristics and vehicle speeds. CO2 levels were investigated under different speeds and ventilation modes. Four modes were s...Factors contributing to ventilation quantity of the vehicle are ventilation modes, cabin characteristics and vehicle speeds. CO2 levels were investigated under different speeds and ventilation modes. Four modes were selected: A: vent closed and fan shut, B: vent closed and fan started, C: vent opened and fan shut, D: vent opened and fan started. In vent closed modes, CO2 levels reached several thousands of ppm in few minutes at any speeds. For mode C, CO2 levels exceeded the guideline at low speeds 50 km/h, while it reduced below one at higher speeds 80 km/h. Fan has no significant impact on ventilation during vent closed. The ventilation efficiency in each mode increased with the speed raising. To determine the ventilation rate of running vehicle, the experiment was implemented by using CO2 emitted from driver and passengers as tracer gas. Ventilation rate for the different modes and speeds were calculated.展开更多
Based on the in situ XBT and other data sets, by analyzing the seasonal cycle of the mixed layer depth (MLD) and using the conservative potential vorticity (PV) as a tool, a clear description of the formation process ...Based on the in situ XBT and other data sets, by analyzing the seasonal cycle of the mixed layer depth (MLD) and using the conservative potential vorticity (PV) as a tool, a clear description of the formation process of the North Pacific Subtropical Mode Water (NPSTMW) is presented for explaining the well known 'Stommel Demon'. The forming of NPSTMW reflects well the ventilation process of the isotherms of the permanent thermocline. The formation process can be divided into the 'ventilation' phase and the 'formation' phase. In the first phase (October-March), with large heat losses at the sea surface from October, the mixed layer deepens and correspondingly, the water mass with low PV emerges and sinks. After continual cooling from October to March, the mixed layer reaches its maximum value ( >300 m) in March. Then, in the second phase (April-June), the mixed layer shoals rapidly from April, a large part of the low PV water mass is sheltered from further air-sea interaction by the emerging seasonal thermocline, and thus forms new NPSTMW. Further analysis indicates that the formation region of warm NPSTMW (17-18℃) is limited between 140°-150°E, while the relatively cold NPSTMW (16-17℃) originates in a wider longitude range (140°-170°E).Climate features of NPSTMW are presented with the use of climatological Levitus (1994 a, b) dataset. It is shown that NPSTMW lies in the region of (130°-170°E, 22°-34°N) with core temperature ranging from about 16-19℃ and potential density around 25-25.8σθ NPSTMW has a three-dimensional structure lying below the seasonal thermocline (about 100 m deep) and reaches almost to 350m depths.展开更多
Objective:To explore the effect of pressure-controlled inverse ratio ventilation on partial pressure of oxygen(PaO_(2)),partial pressure of carbon dioxide(PaC O2),dynamic lung compliance(Cdyn),white blood cell(WBC),pr...Objective:To explore the effect of pressure-controlled inverse ratio ventilation on partial pressure of oxygen(PaO_(2)),partial pressure of carbon dioxide(PaC O2),dynamic lung compliance(Cdyn),white blood cell(WBC),procalcitonin(PCT),C-reactive protein(CRP),and other indicators.Methods:A total of 100 healthy Wistar rats,aged 6-8 weeks and weighing 300-356 g,were used to establish gastric cancer models with 1-methyl-3-nitro-1-nitrosoguanidine(MNNG).60 gastric cancer rats were randomly divided into three groups and treated with laparoscopic radical gastrectomy after anesthesia.Rats in the VCV group were given volume control ventilation,rats in the PCV group were given pressure control ventilation,and rats in the PC-IRV group were given pressure control inverse ratio ventilation.The levels of WBC,PCT and CRP in the three groups were observed and compared on the 1st,3rd and 5th day after operation.Results:There were significant differences in PaO_(2)levels at 15 min after ventilation mode change and at the time of pneumoperitoneum closure,and in PaCO_(2)and Cdyn levels at 10 min after induction and at 15 min after ventilation mode change among the three groups(P<0.05).The PaO_(2)levels in PC-IRV group were higher than those in VCV group and PCV group at 15 min after the ventilation mode was changed and at the time of closing the pneumoperitoneum.The level of PaCO_(2)in PC-IRV group was lower than that in VCV group and PCV group 10 min after induction and 15 min after ventilation mode change,and the level of PaCO_(2)in PC-IRV group was lower than that in VCV group when pneumoperitoneum was turned off.The level of Cdyn in PC-IRV group was higher than that in VCV group and PCV group at 10 min after induction and 15 min after ventilation mode change.The level of Cdyn in PC-IRV group was higher than that in PCV group at the time of closing pneumoperitoneum.The Cdyn level in PCV group was lower than that in VCV group at 15 min after ventilation mode change.There were significant differences in WBC levels among the three groups on the 1st day after operation(P<0.05),and there were no significant differences in PCT and CRP levels among the three groups on the 1st day after operation(P>0.05).There were significant differences in WBC,PCT and CRP levels in the three groups of rats on the 3rd and 5th days after surgery(P<0.05).Except for PCT and CRP on the 1st day after operation,the WBC on the 1st,3rd and 5th days after operation,PCT and CRP on the 3rd and 5th days after operation in PCV group and PC-IRV group were lower than those in VCV group(P<0.05).Except for WBC,PCT and CRP on 1st day after operation,the levels of WBC,PCT and CRP on the 3rd and 5th days after operation in PC-IRV group were lower than those in PCV group(P<0.05).Conclusion:During laparoscopic radical gastrectomy for gastric cancer,pressure-controlled inverse ratio ventilation can help rats maintain good respiratory status and lung compliance during the operation,which can effectively alleviate the postoperative inflammatory response.展开更多
Objective:To study the intraoperative oxygenation function and trauma degree of pressure-controlled ventilation-volume guaranteed (PCV-VG) and volume-controlled ventilation (VCV) mode for elderly patients with laparos...Objective:To study the intraoperative oxygenation function and trauma degree of pressure-controlled ventilation-volume guaranteed (PCV-VG) and volume-controlled ventilation (VCV) mode for elderly patients with laparoscopic abdominal surgery. Methods:60 elderly patients with laparoscopic abdominal surgery were selected for study and randomly divided into two groups (n=30), group A received ventilation in accordance with sequential VCV-PCV-VG mode, group B received ventilation in accordance with the sequential PCV-VG-VCV mode, and the respiratory function parameters and arterial blood gas parameters and serum damage indexes were determined before the start of pneumoperitoneum (T0), 1 h after the start of the first ventilation mode after the start of pneumoperitoneum (T1), 1 h after the switch of ventilation mode (T2) and after the end of pneumoperitoneum (T3). Results:At T1, Ppeak, mean airway pressure (Pmean) and plateau airway pressure (Pplant) of group A were significantly higher than those of group B (P<0.05), partial pressure of oxygen (PaO2) was significantly lower than that of group B (P<0.05), and pulse oxygen saturation (SpO2) and partial pressure of carbon dioxide (PaCO2) were not significantly different from those of group B;at T2 and T3, Ppeak, Pmean and Pplant of group A were significantly lower than those of group B (P<0.05), PaO2 were significantly lower than those of group B (P<0.05), and SpO2 and PaCO2 were not significantly different from those of group B. At T1, serum soluble receptor for advanced glycation end-product (sRAGE), KL-6 (krebs. von den Iungen-6), tumor necrosis factor-α(TNF-α) and malondialdehyde (MDA) content of group A were significantly higher than those of group B (P<0.05);at T3, serum sRAGE, KL-6, TNF-αand MDA content of group A were significantly lower than those of group B (P<0.05). Conclusions:PCV-VG mode for elderly patients with laparoscopic abdominal surgery can reduce airway pressure, improve lung compliance and alveolar oxidation, and reduce lung injury and systemic trauma.展开更多
文摘BACKGROUND Laparoscopic-assisted radical gastrectomy(LARG)is the standard treatment for early-stage gastric carcinoma(GC).However,the negative impact of this proce-dure on respiratory function requires the optimized intraoperative management of patients in terms of ventilation.AIM To investigate the influence of pressure-controlled ventilation volume-guaranteed(PCV-VG)and volume-controlled ventilation(VCV)on blood gas analysis and pulmonary ventilation in patients undergoing LARG for GC based on the lung ultrasound score(LUS).METHODS The study included 103 patients with GC undergoing LARG from May 2020 to May 2023,with 52 cases undergoing PCV-VG(research group)and 51 cases undergoing VCV(control group).LUS were recorded at the time of entering the operating room(T0),20 minutes after anesthesia with endotracheal intubation(T1),30 minutes after artificial pneumoperitoneum(PP)establishment(T2),and 15 minutes after endotracheal tube removal(T5).For blood gas analysis,arterial partial pressure of oxygen(PaO_(2))and partial pressure of carbon dioxide(PaCO_(2))were observed.Peak airway pressure(P_(peak)),plateau pressure(Pplat),mean airway pressure(P_(mean)),and dynamic pulmonary compliance(C_(dyn))were recorded at T1 and T2,1 hour after PP establishment(T3),and at the end of the operation(T4).Postoperative pulmonary complications(PPCs)were recorded.Pre-and postoperative serum interleukin(IL)-1β,IL-6,and tumor necrosis factor-α(TNF-α)were measured by enzyme-linked immunosorbent assay.RESULTS Compared with those at T0,the whole,anterior,lateral,posterior,upper,lower,left,and right lung LUS of the research group were significantly reduced at T1,T2,and T5;in the control group,the LUS of the whole and partial lung regions(posterior,lower,and right lung)decreased significantly at T2,while at T5,the LUS of the whole and some regions(lateral,lower,and left lung)increased significantly.In comparison with the control group,the whole and regional LUS of the research group were reduced at T1,T2,and T5,with an increase in PaO_(2),decrease in PaCO_(2),reduction in P_(peak) at T1 to T4,increase in P_(mean) and C_(dyn),and decrease in Pplat at T4,all significant.The research group showed a significantly lower incidence of PPCs than the control group within 3 days postoperatively.Postoperative IL-1β,IL-6,and TNF-αsignificantly increased in both groups,with even higher levels in the control group.CONCLUSION LUS can indicate intraoperative non-uniformity and postural changes in pulmonary ventilation under PCV-VG and VCV.Under the lung protective ventilation strategy,the PCV-VG mode more significantly improved intraop-erative lung ventilation in patients undergoing LARG for GC and reduced lung injury-related cytokine production,thereby alleviating lung injury.
基金Supported by the National Natural Science Foundation of China(32072787)。
文摘In order to study the effects of ventilation modes and outlet height on the airflow field of a nursery piggery,computational fluid dynamics (CFD) technology was used to simulate the wind speed and temperature of an experimental pig house in the cold northern region.This study was conducted with simulation and a comparative analysis of transverse ventilation,longitudinal ventilation and roof air intake modes.Furthermore,the effects of the air outlet height of 0.7,0.6 and 0.5 m with the roof air inlet mode on the environment in the pig house were studied.Field experiments verified the model of roof air intake model.The results showed inadequate ventilation in both the vertical and horizontal ventilation.However,the airfield gradients were less variable and more balanced when using the rooftop air intake mode.The variation of outlet height significantly affected nursery pig houses’ airflow velocity and temperature.Roof air inlet mode with an outlet height of 0.7 m was better than the other two.The normalized mean square error (NMSE) of air velocity and temperature was less than 0.01,and the simulation analysis could genuinely reflect the distribution of the airflow field in the nursery.
文摘The 1/15 reduced-scale experiments using Froude scaling were designed to study the effect on the smoke control efficiency for subway tunnel fires with natural ventilation mode.The propane gas fires with heat release rate 11.48 kW was used,which corresponds to the heat release rate 10 MW in the full-scale tunnel.The temperature distributions under the ceiling were measured by K-type thermocouples to investigate smoke movement,and the velocity of smoke in shafts was measured by hot-wire anemometer to obtain the smoke extract amount of ventilation shafts.The results show that the smoke temperature under the ceiling varies with the longitudinal different distance from fire source.The results also show that the smoke temperature distributions and the smoke control efficiency in tunnel vary with the space between ventilation shafts and vary with the area and the height of ventilation shaft.
基金Projects(2006BAJ02A02-052006BAJ01A05-06-04) supported by the National Key Technology R&D Program of China
文摘Making the use of ventilation technology may decrease building energy consumption,improve indoor thermal environment,and ameliorate indoor air quality. Combining with the meteorological characteristics in the Changjiang river valley and focusing on Chongqing,this work makes an applied analysis of the feasibility of intermittent mechanical ventilation. By comparison of various ventilation modes,it gives a summary of the suitable ventilation ways for different weather conditions with the combination of testing data and experimental data.
文摘Indoor air environment includes indoor thermal environment and air quality, and a reasonable ventilation provides guarantee for a good indoor environment. A numerical study of the indoor environment in different ventilation is presented in this paper. The External Energy Saving Lab of the WenYuan Building was selected for this purpose, and its indoor air quality and thermal performance in the typical summer climate were simulated. For the numerical simulation, the techniques of Fluent Air-pak was adopted to establish the physical and numerical model of lab. A attention is given to the velocity field and the distribution of pollutant concentration, followed by a discussion of two ventilation modes (displacement ventilation and up-in and up-out ventilation). By comparison, it is found that the Displacement ventilation in improving indoor air quality is obviously superior to the traditional up-in and up-out ventilation.
文摘Factors contributing to ventilation quantity of the vehicle are ventilation modes, cabin characteristics and vehicle speeds. CO2 levels were investigated under different speeds and ventilation modes. Four modes were selected: A: vent closed and fan shut, B: vent closed and fan started, C: vent opened and fan shut, D: vent opened and fan started. In vent closed modes, CO2 levels reached several thousands of ppm in few minutes at any speeds. For mode C, CO2 levels exceeded the guideline at low speeds 50 km/h, while it reduced below one at higher speeds 80 km/h. Fan has no significant impact on ventilation during vent closed. The ventilation efficiency in each mode increased with the speed raising. To determine the ventilation rate of running vehicle, the experiment was implemented by using CO2 emitted from driver and passengers as tracer gas. Ventilation rate for the different modes and speeds were calculated.
基金supported by Free Application(No.40276009)NSFC Project for Oversea Young Scientist Found(No.40028605).
文摘Based on the in situ XBT and other data sets, by analyzing the seasonal cycle of the mixed layer depth (MLD) and using the conservative potential vorticity (PV) as a tool, a clear description of the formation process of the North Pacific Subtropical Mode Water (NPSTMW) is presented for explaining the well known 'Stommel Demon'. The forming of NPSTMW reflects well the ventilation process of the isotherms of the permanent thermocline. The formation process can be divided into the 'ventilation' phase and the 'formation' phase. In the first phase (October-March), with large heat losses at the sea surface from October, the mixed layer deepens and correspondingly, the water mass with low PV emerges and sinks. After continual cooling from October to March, the mixed layer reaches its maximum value ( >300 m) in March. Then, in the second phase (April-June), the mixed layer shoals rapidly from April, a large part of the low PV water mass is sheltered from further air-sea interaction by the emerging seasonal thermocline, and thus forms new NPSTMW. Further analysis indicates that the formation region of warm NPSTMW (17-18℃) is limited between 140°-150°E, while the relatively cold NPSTMW (16-17℃) originates in a wider longitude range (140°-170°E).Climate features of NPSTMW are presented with the use of climatological Levitus (1994 a, b) dataset. It is shown that NPSTMW lies in the region of (130°-170°E, 22°-34°N) with core temperature ranging from about 16-19℃ and potential density around 25-25.8σθ NPSTMW has a three-dimensional structure lying below the seasonal thermocline (about 100 m deep) and reaches almost to 350m depths.
文摘Objective:To explore the effect of pressure-controlled inverse ratio ventilation on partial pressure of oxygen(PaO_(2)),partial pressure of carbon dioxide(PaC O2),dynamic lung compliance(Cdyn),white blood cell(WBC),procalcitonin(PCT),C-reactive protein(CRP),and other indicators.Methods:A total of 100 healthy Wistar rats,aged 6-8 weeks and weighing 300-356 g,were used to establish gastric cancer models with 1-methyl-3-nitro-1-nitrosoguanidine(MNNG).60 gastric cancer rats were randomly divided into three groups and treated with laparoscopic radical gastrectomy after anesthesia.Rats in the VCV group were given volume control ventilation,rats in the PCV group were given pressure control ventilation,and rats in the PC-IRV group were given pressure control inverse ratio ventilation.The levels of WBC,PCT and CRP in the three groups were observed and compared on the 1st,3rd and 5th day after operation.Results:There were significant differences in PaO_(2)levels at 15 min after ventilation mode change and at the time of pneumoperitoneum closure,and in PaCO_(2)and Cdyn levels at 10 min after induction and at 15 min after ventilation mode change among the three groups(P<0.05).The PaO_(2)levels in PC-IRV group were higher than those in VCV group and PCV group at 15 min after the ventilation mode was changed and at the time of closing the pneumoperitoneum.The level of PaCO_(2)in PC-IRV group was lower than that in VCV group and PCV group 10 min after induction and 15 min after ventilation mode change,and the level of PaCO_(2)in PC-IRV group was lower than that in VCV group when pneumoperitoneum was turned off.The level of Cdyn in PC-IRV group was higher than that in VCV group and PCV group at 10 min after induction and 15 min after ventilation mode change.The level of Cdyn in PC-IRV group was higher than that in PCV group at the time of closing pneumoperitoneum.The Cdyn level in PCV group was lower than that in VCV group at 15 min after ventilation mode change.There were significant differences in WBC levels among the three groups on the 1st day after operation(P<0.05),and there were no significant differences in PCT and CRP levels among the three groups on the 1st day after operation(P>0.05).There were significant differences in WBC,PCT and CRP levels in the three groups of rats on the 3rd and 5th days after surgery(P<0.05).Except for PCT and CRP on the 1st day after operation,the WBC on the 1st,3rd and 5th days after operation,PCT and CRP on the 3rd and 5th days after operation in PCV group and PC-IRV group were lower than those in VCV group(P<0.05).Except for WBC,PCT and CRP on 1st day after operation,the levels of WBC,PCT and CRP on the 3rd and 5th days after operation in PC-IRV group were lower than those in PCV group(P<0.05).Conclusion:During laparoscopic radical gastrectomy for gastric cancer,pressure-controlled inverse ratio ventilation can help rats maintain good respiratory status and lung compliance during the operation,which can effectively alleviate the postoperative inflammatory response.
文摘Objective:To study the intraoperative oxygenation function and trauma degree of pressure-controlled ventilation-volume guaranteed (PCV-VG) and volume-controlled ventilation (VCV) mode for elderly patients with laparoscopic abdominal surgery. Methods:60 elderly patients with laparoscopic abdominal surgery were selected for study and randomly divided into two groups (n=30), group A received ventilation in accordance with sequential VCV-PCV-VG mode, group B received ventilation in accordance with the sequential PCV-VG-VCV mode, and the respiratory function parameters and arterial blood gas parameters and serum damage indexes were determined before the start of pneumoperitoneum (T0), 1 h after the start of the first ventilation mode after the start of pneumoperitoneum (T1), 1 h after the switch of ventilation mode (T2) and after the end of pneumoperitoneum (T3). Results:At T1, Ppeak, mean airway pressure (Pmean) and plateau airway pressure (Pplant) of group A were significantly higher than those of group B (P<0.05), partial pressure of oxygen (PaO2) was significantly lower than that of group B (P<0.05), and pulse oxygen saturation (SpO2) and partial pressure of carbon dioxide (PaCO2) were not significantly different from those of group B;at T2 and T3, Ppeak, Pmean and Pplant of group A were significantly lower than those of group B (P<0.05), PaO2 were significantly lower than those of group B (P<0.05), and SpO2 and PaCO2 were not significantly different from those of group B. At T1, serum soluble receptor for advanced glycation end-product (sRAGE), KL-6 (krebs. von den Iungen-6), tumor necrosis factor-α(TNF-α) and malondialdehyde (MDA) content of group A were significantly higher than those of group B (P<0.05);at T3, serum sRAGE, KL-6, TNF-αand MDA content of group A were significantly lower than those of group B (P<0.05). Conclusions:PCV-VG mode for elderly patients with laparoscopic abdominal surgery can reduce airway pressure, improve lung compliance and alveolar oxidation, and reduce lung injury and systemic trauma.