The Effects Of Pulmonary Static Inflation With Different Ways During Cardiopulmonary Bypass On Postoperative Lung Function

Lung injury after extracorporeal circulation is one of common complications after heart surgery, almost all patients after cardiac surgery can appear pulmonary dysfunction. Postoperative pulmonary function injury after extracorporeal circulation clinical manifestations different degrees. Some persons may have only transient symptoms, some persons may be characterized by pulmonary dysfunction, the incidence of 25%, and even for the development of acute respiratory distress syndrome (ARDS), and the mortality can reach more than 50%. It has become one of the main death factors after cardiac surgery. About the mechanism of lung injury after extracorporeal circulation and lung protection have a lot of research reports.The mechanism of lung injury caused by CPB is very complex, many factors involved in the pathophysiological process. Although the exact mechanism of lung injury after extracorporeal circulation is still not very clear, but it is generally believed mainly related to the following factors:1, when exposed to artificial material surface, blood lead to complement activation, inflammatory cytokines release and cascade, activated platelet aggregation function, etc., and eventually lead to systemic inflammatory response syndrome (SIRS).2, During CPB, the pulmonary low perfusion cause lung ischemia and hypoxia state, cell energy metabolism disorder, release a series of inflammatory mediators, cytokines and protein enzymes such as oxygen free radicals, atelectasis, pulmonary vascular resistance increase, lung ischemic injury and ischemia/reperfusion (I/R) injury present.Common lung protective measures include extracorporeal circulation equipment and pipeline improvement, application of ultrafiltration technology, the application of drugs, pulmonary perfusion continuously, liquid ventilation, ischemic preconditioning, lung ventilation during CPB, the other application of mechanical ventilation, etc. Studies have shown that in a specific way of ventilation during extracorporeal circulation can reduce the lung injury after extracorporeal circulation, such as continuous positive airway pressure (CPAP), lung static inflation, positive end expiratory pressure (PEEP), using the effective ventilation (VCM, the airway peak pressure of 40 cm), continuous ventilation and so on, can improve the gas exchange, reduce the occurrence of atelectasis, improve postoperative lung function.Lung static inflation is one of the anesthesiologists can apply during CPB. The ventilation strategy do not need special equipment, and it does not affect the operation, the medical expenses no increase. Static inflation refers to that when mechanical ventilation stop during CPB, continued to blow the lungs into the gas and keep the airway pressure in 5-10 cmH20. However the method about static inflation literature reports vary, such as the pulmonary pressure of static inflation may be 5 cmH2O or 10 cmH20, even 15 cmH20, and the gas oxygen concentration of static inflation may be 21%,50%, or 100%. And the research conclusions are different. This study intends to compare the effects of different static inflation ways on postoperative pulmonary function.Objective1、To assess the effects of pulmonary static inflation with different pressures during cardiopulmonary bypass on postoperative lung function and tracheal intubation time in patients undergoing cardiac valve replacement surgery2、To assess the effects of pulmonary static inflation with different oxygen concentration during cardiopulmnonary bypass on postoperative lung function and tracheal intubation time in patients undergoing cardiac valve replacement surgery.3、To assess the effects of pulmonary static inflation with different concentration of sevoflurane during cardiopulmonary bypass on postoperative lung function and tracheal intubation time in patients undergoing cardiac valve replacement surgery.MethodsIn The effects of pulmonary static inflation with different pressures during cardiopulmonary bypass on postoperative lung function1.1 PatientsWith the Hospital Ethics Committee approval and written informed consent from the patients, fifty patients (aged range 20 to 65 years old, ASA physical status II or III, weighing range 41 to 77 kg, heighten range 150 to 175 cm)undergoing elected cardiac valvular replace surgery were enrolled in this study. All patients were the first time to suffer cardiac surgery. Exclusion criteria included:anemia, fever, pulmonary infection, smoking during recent 3 months, coagulation abnormality, infective endocarditic, Liver or kidney function abnormality, chronic obstructive lung disease. Patients were randomly divided into two groups (n=30), pulmonary static inflation with 5 cmH2O (group L) or 10 cmH2O (group H).1.2 General anesthesiaPremedication consisted of morphine sulfate,0.1 mg/kg and scopolamine 0.01 mg/kg 30 minutes before anesthesia. Anesthesia was induced with intravenous midazolam 0.1 mg/kg, sufentanil 1 ug/kg and pipecuronium bromide 0.1 mg/kg. Continuous electrocardiography, invasive blood pressure (radial artery), end-tidal carbon dioxide and oxyhemoglobin saturation were monitored throughout surgery. Anesthesia was maintained by intravenous midazolam, sufentanil and pipecuronium bromide.Five minutes after heparin sodium 3 mg/kg intravenous through Internal jugular vein for heparinization, activated clotting time(ACT)was monitored. After ACT> 480s, aorta and vena cava cannula were performed, and cardiopulmonary bypass (CPB) were initiated. During CPB,perfusion flow rate were maintained at 2.22.6 L/min/m2,mean arterial pressure were maintained at 50 to 80 mmHg, systemic hypothermia were maintained at 30～32°C, and hematocrit were maintained at 0.18±0.24.1.3 Respiratory managementAfter endotracheal intubation, patients were ventilated with intermittent positive pressure ventilation, ventilation parameters:inhaled oxygen concentration (FiO2) 0.6, tidal volume (VT) 8 ml/kg, breathing rate 10 times/min. After perfusion flow rate reach full flow, ventilation was discontinued in all patients, the oxygen flow valve was closed, adjusting the air flow valve in 1 L/min for lung static inflation, adjusting the breathing machine exhaust valve, keep breathing loop pressure in 5 cm H2O (1 cm H2O=0.098 kPa) group (L) or 10 cmH2O (group H). After inferior vena cava recovered, ventilation was recontinued. The respiratory parameters was the same as that before CPB after CPB was weaning, and positive end expiratory pressure (PEEP) 4 cm H2O was performed at the same time. After the patients arrival in the intensive care unit (ICU), FiO2 was changed to 0.4, PEEP 4 cm H2O was continue.1.4 Observation indexes and observation time points1.4.1 Observation indexesHeart rate (HR)Radial artery blood pressure (SBP, DBP, MAP)Central venous pressure (CVP)Electrocardiogram (ECG)Pulse oxygen saturation (SpO2)End expiratory CO2 partial pressure (PETCO2)Arterial oxygen partial pressure (PaO2)Artery co2 partial pressure (PaCO2)Oxygenation indexAlveolar-arterial blood oxygen partial pressure differences [D(A-a)o2]Respiratory index (RI)Oxygenation index (OI)The time of ascending aorta blockThe time of CPBThe operation timeThe time of extubationICU stay time1.4.2 Monitoring time pointsTO before operation beginningT1 1 hour after CPB weaningT2 3 hour after CPB weaningT3 6 hour after CPB weaning1.4.3 Variables recorded and calculatedIntermittent arterial blood gas analysis was performed at TO to T3, the MAP, HR, CVP were recorded at the same time points. The D(A-a)O2, RI,OI were calculated.D(A-a)02= 713xFiO2-PaCO2/0.8-PaO2RI=D(A-a)O2/PaO2OI=PaO2/FiO2The time of The time of ascending aorta block, CPB, operation, extubation and ICU stay time were recorded too.1.5 Statistical analysesThe SPSS 13.0 statistical soft package was used for all statistical analyses. Data are expressed as mean ± SD. The single factor analysis of variance was used to compare the data between groups. The repeated measurements analysis of variance was used to compare the data within groups at diffent time points. Count data was compared by chi-square test or Fisher’s exact probability method. A P value<0.05 was considered to indicate statistical significance.2、The effects of pulmonary static inflation with different oxygen concentration during cardiopulmonary bypass on postoperative lung function2.1 PatientsWith the Hospital Ethics Committee approval and written informed consent from the patients, fifty patients (aged range 22 to 64 years old, ASA physical status II or III, weighing range 50 to 76 kg, heighten range 152 to 175 cm) undergoing elected cardiac valvular replace surgery were enrolled in this study. All patients were the first time to suffer cardiac surgery. Exclusion criteria included:anemia, fever, pulmonary infection, smoking during recent 3 months, coagulation abnormality, infective endocarditic, Liver or kidney function abnormality, chronic obstructive lung disease. Patients were randomly divided into two groups (n=30), pulmonary static inflation with 21% oxygen concentration (group L) or 100% oxygen concentration (group H).2.2 General anesthesiaPremedication consisted of morphine sulfate,0.1 mg/kg and scopolamine 0.01 mg/kg 30 minutes before anesthesia. Anesthesia was induced with intravenous midazolam 0.1 mg/kg, sufentanil 1 ug/kg and pipecuronium bromide 0.1 mg/kg Continuous electrocardiography, invasive blood pressure (radial artery), end-tidal carbon dioxide and oxyhemoglobin saturation were monitored throughout surgery. Anesthesia was maintained by intravenous midazolam, sufentanil and pipecuronium bromide.Five minutes after heparin sodium 3 mg/kg intravenous through Internal jugular vein for heparinization, activated clotting time (ACT) was monitored. After ACT> 480s, aorta and vena cava cannula were performed, and cardiopulmonary bypass (CPB) were initiated. During CPB, perfusion flow rate were maintained at 2.2～2.6 L/min/m2, mean arterial pressure were maintained at 50 to 80 mmHg, systemic hypothermia were maintained at 30～32°C, and hematocrit were maintained at 0.18±0.24.2.3 Respiratory managementAfter endotracheal intubation, patients were ventilated with intermittent positive pressure ventilation, ventilation parameters:inhaled oxygen concentration (FiO2) 0.6, tidal volume (VT) 8 ml/kg, breathing rate 10 times/min. After perfusion flow rate reach full flow, ventilation was discontinued in all patients, the oxygen flow valve was closed in group L, adjusting the air flow valve in 1 L/min for lung static inflation, adjusting the breathing machine exhaust valve, keep breathing loop pressure in 10 cm H2O (1 cm H2O=0.098 kPa).And the air flow valve was closed in group H, adjusting the oxygen flow valve in 1 L/min for lung static inflation, adjusting the breathing machine exhaust valve, keep breathing loop pressure in 10 cm H2O.After inferior vena cava recovered, ventilation was recontinued. The respiratory parameters was the same as that before CPB after CPB was weaning, and positive end expiratory pressure (PEEP) 4 cm H2O was performed at the same time. After the patients arrival in the intensive care unit (ICU), FiO2 was changed to 0.4, PEEP 4 cm H2O was continue.2.4 Observation indexes and observation time points2.4.1 Observation indexesHeart rate (HR)Radial artery blood pressure (SBP, DBP, MAP)Central venous pressure (CVP)Electrocardiogram (ECG)Pulse oxygen saturation (SpO2)End expiratory CO2 partial pressure (PETCO2)Arterial oxygen partial pressure (PaO2)Artery co2 partial pressure (PaCO2)Oxygenation indexAlveolar-arterial blood oxygen partial pressure differences [D(A-a)02]Respiratory index (RI)Oxygenation index (01)The time of ascending aorta blockThe time of CPBThe operation timeThe time of extubationICU stay time2.4.2 Monitoring time pointsTO before operation beginningT1 1 hour after CPB weaningT2 3 hour after CPB weaningT3 6 hour after CPB weaning2.4.3 Variables recorded and calculatedIntermittent arterial blood gas analysis was performed at TO to T3, the MAP, HR, CVP were recorded at the same time points. The D(A-a)02,RI,OI were calculated.D(A-a)O2= 713xFiO2-PaCO2/0.8-PaO2RI=D(A-a)O2/PaO201=PaO2/FiO2The time of The time of ascending aorta block, CPB, operation, extubation and ICU stay time were recorded too.2.5 Statistical analysesThe SPSS 13.0 statistical soft package was used for all statistical analyses. Data are expressed as mean ± SD. The single factor analysis of variance was used to compare the data between groups. The repeated measurements analysis of variance was used to compare the data within groups at diffent time points. Count data was compared by chi-square test or Fisher’s exact probability method. A P value<0.05 was considered to indicate statistical significance.3、 The effects of pulmonary static inflation with different concentration of sevoflurane during cardiopulmonary bypass on postoperative lung function3.1 PatientsWith the Hospital Ethics Committee approval and written informed consent from the patients, fifty patients (aged range 25 to 62 years old, ASA physical status II or III, weighing range 51 to 75 kg, heighten range 151 to 177 cm) undergoing elected cardiac valvular replace surgery were enrolled in this study. All patients were the first time to suffer cardiac surgery. Exclusion criteria included: anemia, fever, pulmonary infection, smoking during recent 3 months, coagulation abnormality, infective endocarditic, Liver or kidney function abnormality, chronic obstructive lung disease. Patients were randomly divided into two groups (n=30), pulmonary static inflation with 1% sevoflurane (group L) or 2% sevoflurane (group H).3.2 General anesthesiaPremedication consisted of morphine sulfate,0.1 mg/kg and scopolamine 0.01 mg/kg 30 minutes before anesthesia. Anesthesia was induced with intravenous midazolam 0.1 mg/kg, sufentanil 1 ug/kg and pipecuronium bromide 0.1 mg/kg. Continuous electrocardiography, invasive blood pressure (radial artery), end-tidal carbon dioxide and oxyhemoglobin saturation were monitored throughout surgery. Anesthesia was maintained by intravenous midazolam, sufentanil and pipecuronium bromide.Five minutes after heparin sodium 3 mg/kg intravenous through Internal jugular vein for heparinization, activated clotting time (ACT) was monitored. After ACT> 480s, aorta and vena cava cannula were performed, and cardiopulmonary bypass (CPB) were initiated. During CPB,perfusion flow rate were maintained at 2.2～2.6 L/min/m2,mean arterial pressure were maintained at 50 to 80 mmHg, systemic hypothermia were maintained at 30～32°C, and hematocrit were maintained at 0.18～0.24. After CPB beginning, open the pipeline loop sevoflurane volatile cans, inhaled sevoflurane concentration of 1%(group L) or 2%(group H).2.3 Respiratory managementAfter endotracheal intubation, patients were ventilated with intermittent positive pressure ventilation, ventilation parameters:inhaled oxygen concentration (FiO2) 0.6, tidal volume (VT) 8 ml/kg, breathing rate 10 times/min. After CPB beginning, open sevoflurane cans, inhaled sevoflurane concentration of 1%(group L) or 2%(group H) At the same time adjust the fresh gas flow to 3 L/min air and 3 L/min oxygen, lasts for 5 min. After blocking the inferior vena cava, ventilation was discontinued in all patients, close the oxygen flow valve, adjusting the air flow valve in 1 L/min, adjusting the breathing machine exhaust valve, keep breathing loop pressure in 10 cm H2O (1 cm H2O=0.098 kPa).After inferior vena cava recovered, ventilation was recontinued, and closing the sevoflurane cans.The respiratory parameters was the same as that before CPB after CPB was weaning, and positive end expiratory pressure (PEEP) 4 cm H2O was performed at the same time.After the patients arrival in the intensive care unit (ICU), FiO2 was changed to 0.4, PEEP 4 cm H2O was continue.3.4 Observation indexes and observation time points3.4.1 Observation indexesHeart rate (HR)Radial artery blood pressure (SBP, DBP, MAP)Central venous pressure (CVP)Electrocardiogram (ECG)Pulse oxygen saturation (SpO2)End expiratory CO2 partial pressure (PETCO2)Arterial oxygen partial pressure (PaO2)Artery co2 partial pressure (PaCO2)Oxygenation indexAlveolar-arterial blood oxygen partial pressure differences [D(A-a)O2]Respiratory index (RI)Oxygenation index (OI)The time of ascending aorta blockThe time of CPBThe operation timeThe time of extubationICU stay time3.4.2 Monitoring time pointsTO before operation beginningTl 1 hour after CPB weaningT2 3 hour after CPB weaningT3 6 hour after CPB weaning3.4.3 Variables recorded and calculatedIntermittent arterial blood gas analysis was performed at TO to T3,the MAP, HR, CVP were recorded at the same time points.The D(A-a)O2, RI,01 were calculated.D(A-a)02= 713xFiO2-PaCO2/0.8-PaO2RI=D(A-a)O2/PaO2OI=PaO2/FiO2The time of The time of ascending aorta block, CPB, operation, extubation and ICU stay time were recorded too.3.5 Statistical analysesThe SPSS 13.0 statistical soft package was used for all statistical analyses.Data are expressed as mean±SD. The single factor analysis of variance was used to compare the data between groups. The repeated measurements analysis of variance was used to compare the data within groups at diffent time points. Count data was compared by chi-square test or Fisher’s exact probability method. A P value< 0.05 was considered to indicate statistical significance.Results1、The effects of pulmonary static inflation with different pressures during cardiopulmonary bypass on postoperative lung function1.1 Demographic dataThe two groups were comparable in terms of age, weight, height, type of operation, the time of ascending aorta block, the time of CPB, operation time, the time of extubation postoperative and ICU stay time. There was no statistically significant difference (P>0.05).1.2 The change of hemodynamic indexes and PaO2,PaCO2There was no statistically significant difference between groups of MAP, HR, and CVP at each point (P>0.05). Compared with T0, the PaO2 at T1,T2, T3 of two groups decrease, the PaCO2 at T2 of two groups increase, the difference was statistically significant (P<0.05).Compared with group L,the PaCO2 at T1,T2,T3 of group H increases,the difference was statistically significant (P<0.05).1.3 Pulmonary oxygen exchange indexCompared with group L,the D(A-a)O2, RI at T1,T2,T3 of group H decrease, OI at T1, T2, T3 of group H increase,the difference was statistically significant (P< 0.05).Compared with TO,the D(A-a)O2, RI at T1,T2,T3 of group L increase,OI at T1,T2,T3 of group L decrease, the D(A-a)O2 at T1,RI at T1,T2 of group H increase, OI at T1,T2,T3 of group H group decrease, the difference was statistically significant (P<0.05).1.4 OI< 300 mmHg of two groups at each pointThere was no statistically significant difference of the cases OI<300 mmHg between groups at TO (P>0.05), the difference of the cases OI<300 mmHg at T1, T2,T3 was statistically significant (P<0.05), the cases OI<300 mmHg of group H was lower than that of group L2、The effects of pulmonary static inflation with different oxygen concentration during cardiopulmonary bypass on postoperative lung function2.1 Demographic dataThe two groups were comparable in terms of age,weight, height, type of operation, the time of ascending aorta block, the time of CPB,operation time, the time of extubation postoperative and ICU stay time.There was no statistically significant difference (P>0.05).2.2 The change of hemodynamic indexes and PaO2, PaCO2There was no statistically significant difference between groups of MAP, HR, and CVP at each point (P>0.05).Compared with TO,the PaO2 at T1,T2, T3 of two groups decrease,the PaCO2 at T2 of two groups increase,the difference was statistically significant (P<0.05).There was no statistically significant difference between groups of PaO2,PaCO2 at each points (P>0.05).2.3 Pulmonary oxygen exchange indexThere was no statistically significant difference between groups of D(A-a)O2,RI, OI at each points (P>0.05).Compared with TO,the D(A-a)O2, RI at T1,T2,T3 of two groups increase, OI at T1,T2,T3 of two groups decrease, the difference was statistically significant (P<0.05).2.4 OI< 300 mmHg of two groups at each pointThere was no statistically significant difference of the cases OI<300 mmHg between groups at each points (P>0.05).3、 The effects of pulmonary static inflation with different concentration of sevoflurane during cardiopulmonary bypass on postoperative lung function3.1 Demographic dataThe two groups were comparable in terms of age, weight, height, type of operation, the time of ascending aorta block, the time of CPB, operation time, the time of extubation postoperative and ICU stay time. There was no statistically significant difference (P>0.05).3.2 The change of hemodynamic indexes and PaO2, PaCO2There was no statistically significant difference between groups of MAP, HR, and CVP at each point (P>0.05). Compared with TO, the PaO2 at T1, T2, T3 of two groups decrease, the PaCO2 at T2 of two groups increase, the difference was statistically significant (P<0.05).There was no statistically significant difference between groups of PaO2. PaCO2 at each points (P>0.05).3.3 Pulmonary oxygen exchange indexCompared with TO, the D(A-a)O2, RI at Tl, T2, T3 of two groups increase, OI at Tl, T2,T3 of two groups decrease, the difference was statistically significant (P< 0.05). Compared with group L, the RI of group H at T3 was increase, there was no significant difference between groups of D(A-a)O2, OI at each points (P>0.05).3.401< 300 mmHg of two groups at each pointThere was no statistically significant difference of the cases OI< 300 mmHg between groups at each points (P> 0.05). The cases OI<300 mmHg of group H at T2, T3 may higher than group LConclusion1. To adult patients with valvular replacement surgery under extracorporeal circulation, postoperative lung injury present, pulmonary oxygenation function and pulmonary gas exchange function decline, compared with preoperative, postoperative PaO2 decrease, D(A-a)O2, RI increase, and OI decrease.2. To adult patients with valvular replacement surgery under extracorporeal circulation, compare with 5 cm H2O, lung static inflation with 10 cmH20, postoperative PaO2 increase, D(A-a)O2, RI decrease, and OI increase. It means that lung static inflation with 10 cmH20 is superior to with 5 cm H2O.3. To adult patients with valvular replacement surgery under extracorporeal circulation, lung static inflation with 10 cmH2O, there was no significant difference between groups (lung static inflation with 21%oxygen concentration and with 100% oxygen concentration) of postoperative PaO2, D(A-a)O2, RI, and OI. It means that there was no significant difference between lung static inflation with 21%oxygen concentration and with 100%oxygen concentration.4. Lung static inflation can improve postoperative lung function after cardiopulmonary bypass, a certain range, increase the pressure is superior to increase the oxygen concentration. Lung static inflation with different ways does not affect the time of extubation postoperative and ICU stay time.5. To adult patients with valvular replacement surgery under extracorporeal circulation, lung static inflation with 10 cmH2O, inhalation of sevoflurane at the same time, there was no significant difference between inhalation of 1% and 2% sevoflurane. The cases OI<300 mmHg postoperative of group H (inhalation of 2% sevoflurane) may higher than group L (inhalation of 1% sevoflurane).