ABSTRACT
Resumen: Introducción: La comorbilidad pulmonar postoperatoria dependerá de factores relacionados con el paciente, modificables y no modificables, pero definitivamente los parámetros ventilatorios intraoperatorios tienen un rol fundamental. Existen índices de oxigenación (IO) que pueden resultar útiles en la evaluación del grado de lesión pulmonar. Material y métodos: Estudio prospectivo, descriptivo, analítico, de casos y controles. Pacientes que requirieron intervención neuroquirúrgica (urgente o electiva) y ventilación mecánica invasiva para el procedimiento. Durante el periodo comprendido entre el 1o de enero de 2018 al 31 de diciembre de 2018. Los pacientes que cumplieron con los criterios de inclusión se asignaron uno a uno para pertenecer al grupo Vt Intermedio (> 8 a < 10 mL/kg peso predicho) o al grupo Vt Bajo (6-8 mL/kg peso predicho). La PEEP fue determinada a consideración del médico (anestesiólogo). Resultados: En el periodo considerado se incluyeron 60 pacientes, los cuales cumplieron con los criterios de inclusión. Del total, 30 pacientes se incluyeron en el grupo Vt Intermedio (VtI) y 30 pacientes en el grupo Vt Bajo (VtB). La modalidad ventilatoria más utilizada fue asisto-control-volumen (ACV) con 96.7% para VtI y 100% para VtB con p = 0.3. El Vt por peso predicho en el grupo de VtI tuvo una media de 8.9 mL/kg y en el grupo de VtB una media de 7.1 mL/kg con una p = 0.001. La escala de coma de Glasgow (ECG) posterior a la extubación fue de 14.3 puntos y 14.4 puntos para VtI y VtB sin diferencia estadísticamente significativa. Conclusión: Utilizar volumen corriente intermedio (> 8 a < 10 mL/kg peso predicho) en los pacientes neuroquirúrgicos ocasiona alteración de los índices de oxigenación: PaO2/FiO2 y PaO2/PAO2. El nivel de PEEP durante el perioperatorio de los pacientes neuroquirúrgicos no ocasiona diferencia significativa en la escala de coma de Glasgow.
Abstract: Introduction: Postoperative pulmonary comorbidity will depend on factors related to the patient, modifiable and non-modifiable, but intraoperative ventilatory parameters definitely play a fundamental role. There are oxygenation indices (OI) that may be useful in assessing the degree of lung injury. Material and methods: Prospective, descriptive, analytical, case-control study. Patients who required neurosurgical intervention (urgent or elective) and invasive mechanical ventilation for the procedure. During the period from January 1, 2018 to December 31, 2018. Patients who met the inclusion criteria were assigned 1 to 1 to belong to the Intermediate Tidal Volumen group (ItV) (> 8 to < 10 mL/kg predicted weight) or to the Low Tidal Volumen group (LtV) (6-8 mL/kg predicted weight). PEEP was determined for the doctor's consideration (anesthesiologist). Results: In the period considered, 60 patients were included who met the inclusion criteria. Of the total, 30 patients were included in the ItV group and 30 patients in the LtV group. The most commonly used ventilatory modality was asysto-control-volume (ACV) with 96.7% for ItV and 100% for LtV with p = 0.3. The predicted weight tV in the ItV group had an average of 8.9 mL/kg and in the LtV group an average of 7.1 mL/kg with a p = 0.001 The Glasgow coma scale (GCE) after extubation was of 14.3 points and 14.4 points for ItV and LtV without statistically significant difference. Conclusion: Using intermediate tidal volume (> 8 to < 10 mL/kg predicted weight) in neurosurgical patients, causes alteration of oxygenation rates: PaO2/FiO2 and PaO2/PAO2. The level of PEEP during the perioperative period of neurosurgical patients does not cause a significant difference in the Glasgow coma scale.
Resumo: Introdução: A comorbidade pulmonar pós-operatória vai depender de fatores relacionados ao paciente, modificáveis e não modificáveis, mas os parâmetros ventilatórios intra-operatórios certamente têm papel fundamental. Existem índices de oxigenação (IO) que podem ser úteis na avaliação do grau de lesão pulmonar. Material e métodos: Estudo prospectivo, descritivo, analítico, caso-controle. Pacientes que necessitaram de intervenção neurocirúrgica (urgente ou eletiva) e ventilação mecânica invasiva para o procedimento. Durante o período de 1o de janeiro de 2018 a 31 de dezembro de 2018. Os pacientes que preencheram os critérios de inclusão foram designados de 1 a 1 para pertencer ao grupo Vt Intermediário (> 8 a < 10 mL/kg de peso previsto) ou para o grupo Vt Baixo (6-8 mL/kg de peso previsto). A PEEP foi determinada por consideração do médico (anestesiologista). Resultados: No período considerado, foram incluídos 60 pacientes que atenderam aos critérios de inclusão. Do total, 30 pacientes foram incluídos no grupo Vt Intermediário (VtI) e 30 pacientes no grupo Vt Baixo (VtB). A modalidade ventilatória mais utilizada foi o volume assistido-controlado (VAC) com 96.7% para VtI e 100% para VtB com p = 0.3. O Vt previsto em peso no grupo VtI teve média de 8.9 mL/kg e no grupo VtB média de 7.1 mL/kg com p = 0.001. A escala de coma de Glasgow (ECG) após a extubação foi de 14.3 pontos e 14.4 pontos para VtI e VtB sem diferença estatisticamente significativa. Conclusão: O uso de volume corrente intermediário (> 8 a < 10 mL/kg de peso previsto) em pacientes neurocirúrgicos causa alteração nos índices de oxigenação: PaO2/FiO2 e PaO2/PAO2. O nível de PEEP durante o período perioperatório de pacientes neurocirúrgicos não causa diferença significativa na escala de coma de Glasgow.
ABSTRACT
@#【Objective】To determine the effects of an open-lung strategy（OLS）comprising moderate positive end- expiratory pressure （PEEP） and intermittent recruitment manoeuvres（RMs） on plasma levels of lung epithelial injury markers［i.e. soluble receptor for advanced glycation end products（sRAGE）and Clara cell protein（CC16）］during low- tidal-volume ventilation for surgery.【Methods】One hundred patients who were undergoing laparoscopic colorectal cancer resection under low-tidal-volume ventilation were enrolled in this study. They were randomly assigned（1∶1）to the OLS group（using PEEP of 6~8 cmH2O and intermittent RM），or the NOLS group（without using PEEP and RM）. Blood samples were taken before anesthesia induction（T1），immediately after surgery（T2）and the postoperative day 3（T3）to measure the plasma concentrations of sRAGE and CC16. 【Results】 Significant differences were not observed in the concentrations of sRAGE and CC16 at T1，T2 and T3 between the two groups（all P > 0.05）. For all the enrolled patients， the concentrations of sRAGE at T2 and T3 were higher than that at T1，the concentration of sRAGE at T3 was higher than that at T2，and the concentration of CC16 at T3 was higher than that at T1 and T2（all P < 0.05）.【Conclusions】In patients under general anesthesia with low-tidal-volume ventilation，the using of an OLS comprising medium PEEP and intermittent RMs can not alter plasma levels of lung epithelial injury markers（sRAGE and CC16）in three days after surgery.
ABSTRACT
Objective To research the application of low tidal volume, apnea ventilation and low PEEP in soft ureteroscope surgery. Methods 80 patients with renal calculi who underwent ureteroscopic holmium laser lithotripsy were randomly divided into tow groups, 40 patients in each group. The observation group was treated with low tidal volume, apnea ventilation and Low PEEP, and the control group was treated with low tidal volume and apnea ventilation. Recorded the HR, MBP, PaCO2, PaO2, Ppeak, A-aDO2, and recorded A-aDO2at pre-anesthesia, preoperation, tracheal extubation, 30 min after tracheal extubation and 24 hours after surgery in tow groups. And observed the trend of RI and CLdyn in tow groups. Results There were no satistically significant differences of HR, MBP, Ppeak and Pmean after recovery and that before apnea in the observation group (P > 0.05); the HR, MBP, Ppeak and Pmean of the observation group was lower than that of the control group after recovery (P < 0.05); the PaO2 of the observation group was higher than that of the control group after recovery (P < 0.05); at tracheal extubation, 30min after tracheal extubation and 24 hours after surgery, the A-aDO2 of the observation group was lower than thatof the control group (P < 0.05); the CLdyn 20 in the observation group was better than that in the control group(P < 0.05). Conclusion In soft ureteroscope surgery, the application of Low tidal volume, apnea ventilation andlow PEEP can ensure the asfe of operation, and maintain the vital aspect, results of blood gas analysis smoothly; andprotect the lung function, promote the recovery of the patients.
ABSTRACT
Objective · To investigate the effects of low tidal volume mechanical ventilation and low level of positive end expiratory pressure (PEEP) on respiratory function in patients with asthma under general anesthesia. Methods · Forty-five patients with asthma undergoing upper abdominal surgery under general anesthesia were selected and randomly divided into three groups, with 15 cases in each group. Group A received a regular tidal volume of 10 mL/kg, group B a low tidal volume of 6 mL/kg and group C a low tidal volume of 6 mL/kg combined with 5 cmH2O PEEP. Ppeak was recorded at different time points, including the time of induction under anesthesia and the time of 5, 30 and 60 minutes after anesthesia induction. Based on such parameters, Cdyn were also calculated. Moreover, blood gas analysis index (PaO2 and PaCO2) were documented at the time of deoxidation period for 5 minutes before induction and 60 and 120 minutes after induction of anesthesia. Results · The Ppeak values in goup C were significantly lower at all times (P<0.01) and Cdyn at the time of 60 and 120 minutes after induction were significantly higher (P<0.05) than group A. At the time of 60 and 120 minutes after induction, the levels of PaO2 were also increased (P<0.01) while the levels of PaCO2 was significantly decreased (P<0.05) in group C compared to group A and group B respectively. Conclusion · The intermittent positive pressure ventilation of low tidal volume combined with low level of PEEP is a safe and effective mechanical ventilation method for asthma patients under general anesthesia, which can reduce airway peak pressure, enhance pulmonary dynamic compliance and improve the oxygenation index.
ABSTRACT
Objective · To investigate the effects of low tidal volume mechanical ventilation and low level of positive end expiratory pressure (PEEP) on respiratory function in patients with asthma under general anesthesia. Methods · Forty-five patients with asthma undergoing upper abdominal surgery under general anesthesia were selected and randomly divided into three groups, with 15 cases in each group. Group A received a regular tidal volume of 10 mL/kg, group B a low tidal volume of 6 mL/kg and group C a low tidal volume of 6 mL/kg combined with 5 cmH2O PEEP. Ppeak was recorded at different time points, including the time of induction under anesthesia and the time of 5, 30 and 60 minutes after anesthesia induction. Based on such parameters, Cdyn were also calculated. Moreover, blood gas analysis index (PaO2 and PaCO2) were documented at the time of deoxidation period for 5 minutes before induction and 60 and 120 minutes after induction of anesthesia. Results · The Ppeak values in goup C were significantly lower at all times (P<0.01) and Cdyn at the time of 60 and 120 minutes after induction were significantly higher (P<0.05) than group A. At the time of 60 and 120 minutes after induction, the levels of PaO2 were also increased (P<0.01) while the levels of PaCO2 was significantly decreased (P<0.05) in group C compared to group A and group B respectively. Conclusion · The intermittent positive pressure ventilation of low tidal volume combined with low level of PEEP is a safe and effective mechanical ventilation method for asthma patients under general anesthesia, which can reduce airway peak pressure, enhance pulmonary dynamic compliance and improve the oxygenation index.
ABSTRACT
Objective To explore the efficacy of low tidal volume ventilation strategy in children with acute hypoxia respiratory failure (AHRF).Methods A total of 79 hospitalized children with AHRF from Aug 2006 to Jul 2011 in PICU of Kunming Children's Hospital were enrolled in this study.The observation group in-cluded 55 children who received low tidal volume ventilation strategy (6-8 ml /kg),while the other 24 children (control group)were given traditional mechanical ventilation (10-12 ml /kg).Oxygenation situations such as PaO2 ,PaCO2 ,PaO2 /FiO2 ,oxygen index and blood gas pH value,organ function,mechanical ventilation complica-tions,hospitalization days and expenses in PICU and the mortality were observed.Results (1)PaO2 ,PaO2 /FiO2 and oxygen index in the observation group were better than those in control group after 24 h mechanical ventilation [(68.51 ±7.53)mmHg(1 mmHg =0.133 kPa)vs.(61.64 ±9.28)mmHg,(162.9 ±21.84)mmHg vs.(152.1 ± 19.03)mmHg,and 18.85 ±4.1 vs.26.53 ±5.2,respectively],and there were significant differences between two groups (P ﹤0.05);and there were also significant differences between two groups in the results after 48 h and 72 h mechanical ventilation.(2)The PaCO2 was (47.48 ±10.52)mmHg after 24 h in observation group,while the PaCO2 in control group was (30.17 ±6.59)mmHg,and it suggested excessive ventilation.(3)Mechanical venti-lation time (7.6 ±3.1)d and hospitalization days (12.8 ±3.6)d were shorter in observation group(P ﹤0.01). Barotrauma (7.3%)and mortality (20.0%)in observation group was significantly lower than those in control group (29.2%,41.6%;P ﹤0.01).The number of damaged organs in observation group was lower than that in control group (P ﹤0.05).Conclusion Low tidal volume ventilation with appropriate positive end expiratory pressure could improve oxygenation,prevent alveolar collapse,reduce complications and mortality for children with AHRF,it should be applied for the treatment of children with AHRF.
ABSTRACT
Objective To investigate the effect of penehyclidine hydrochloride combined with low tidal volume ventilation on lung function in patients with lower abdominal operation.Methods Sixty elderly patients who underwent elective lower abdominal operation were divided into three groups by random digits table method:the conventional tidal volume group (group A),penehyclidine hydrochloride combined with conventional tidal volume group (group B) and penehyclidine hydrochloride combined with low tidal volume group (group C),20 cases in each group.The patients in group B and group C were given penehyclidine hydrochloride 0.01 mg/kg before induction of anesthesia.The patients in group A were given equal volume of saline.After induction of anesthesia and mechanical ventilation modes:the patients in group A and group B were given tidal volume 10 ml/kg,the patients in group C were given tidal volume 6 ml/kg.After mechanical ventilation in anesthetized (T1),1 h after anesthesia (T2),2 h after anesthesia (T3),8 h after anesthesia (T4),24 h after anesthesia (T5),the level of tumor necrosis factor alpha (TNF-α),interleukin-6 (IL-6),pH,arterial partial pressure of oxygen (PaO2),arterial partial pressure of carbon dioxide (PaCO2),the calculation of oxygenation index (PaO2/FiO2) were measured and compared.The pulmonary complications after operation 1 day were recorded.Results The level of TNF-α,IL-6 in three patients at T1 had no significant difference (P ＞ 0.05).The level of TNF-α,IL-6 at T2-5 in group C were significantly lower than those in group A and group B (P ＜ 0.05).Compared with group A and group B,the level of PaO2 and PaO2/FiO2 at T2-5 were increased in group C (P ＜ 0.05).None pulmonary complications were occurred in three groups.Conclusions Penehyclidine hydrochloride combined with low tidal volume ventilation may improve arterial oxygen in patients with lower abdominal operation,reduce the lung injury induced by mechanical ventilation,protective effect on lung function.
ABSTRACT
OBJECTIVE: To determine the utility of pulse pressure variation (ΔRESP PP) in predicting fluid responsiveness in patients ventilated with low tidal volumes (V T) and to investigate whether a lower ΔRESP PP cut-off value should be used when patients are ventilated with low tidal volumes. METHOD: This cross-sectional observational study included 37 critically ill patients with acute circulatory failure who required fluid challenge. The patients were sedated and mechanically ventilated with a V T of 6-7 ml/kg ideal body weight, which was monitored with a pulmonary artery catheter and an arterial line. The mechanical ventilation and hemodynamic parameters, including ΔRESP PP, were measured before and after fluid challenge with 1,000 ml crystalloids or 500 ml colloids. Fluid responsiveness was defined as an increase in the cardiac index of at least 15%. ClinicalTrial.gov: NCT01569308. RESULTS: A total of 17 patients were classified as responders. Analysis of the area under the ROC curve (AUC) showed that the optimal cut-off point for ΔRESP PP to predict fluid responsiveness was 10% (AUC = 0.74). Adjustment of the ΔRESP PP to account for driving pressure did not improve the accuracy (AUC = 0.76). A ΔRESP PP>10% was a better predictor of fluid responsiveness than central venous pressure (AUC = 0.57) or pulmonary wedge pressure (AUC = 051). Of the 37 patients, 25 were in septic shock. The AUC for ΔRESP PP>10% to predict responsiveness in patients with septic shock was 0.484 (sensitivity, 78%; specificity, 93%). CONCLUSION: The parameter D RESP PP has limited value in predicting fluid responsiveness in patients who are ventilated with low tidal volumes, but a ΔRESP PP>10% is a significant improvement over static parameters. A ΔRESP PP > 10% may be particularly useful for identifying responders in patients with septic shock.
Subject(s)
Adult , Aged , Aged, 80 and over , Female , Humans , Male , Middle Aged , Young Adult , Blood Pressure/physiology , Blood Volume/physiology , Respiration, Artificial/methods , Tidal Volume/physiology , Critical Illness , Cross-Sectional Studies , Cardiac Output/physiology , Fluid Therapy , Predictive Value of Tests , ROC Curve , Shock, Septic/physiopathologyABSTRACT
@#BACKGROUND: This study aimed to observe the effect of recruitment maneuver (RM) and post-RM ventilation at different tidal volume on lung vascular diastole endothelial function in rats with acute lung injury (ALI). METHODS: A ALI rat model was produced by intravenous infusion of lipopolysaccharide (6 mg/kg). Twenty-five rats were randomly divided into five groups: control group (n=5), ALI group (n=5), low tidal volume group (LV group, VT 6 mL/kg, n=5), sustained inflation (SI) with low tidal volume group (SI+LV group, VT 6 mL/kg, n=5), and SI with moderate tidal volume group (SI+MV group, VT 12 mL/kg, n=5). RM was performed with SI, airway pressure 30 cmH2O for 30 seconds, and positive end-expiratory pressure (PEEP) was set to 5 cmH2O. Lung tissue was taken after 5 hours of mechanical ventilation. Mean arterial blood pressure (MAP) was monitored during the experiment. Endothelin-1 (ET-1), endothelial nitricoxide synthase (eNOS), Ach-induced endothelium-dependent relaxation response of isolated pulmonary artery rings were determined at 5 hours. RESULTS: LPS increased ET-1 level, decreased the expression of eNOS in lung tissue, impaired the Ach-induced endothelium-dependent relaxation response in the pulmonary artery, without obvious effect on systemic hemodynamics. SI+LV significantly reduced LPS-induced elevation of ET-1 level, increased the expression of eNOS, significantly improved endothelial dysfunction, and improved the dysfunction of endothelium-dependent relaxation in the pulmonary artery. CONCLUSIONS: RM with a high or low tidal volume ventilation could improve the lung vascular endothelial function of rats with acute lung injury, and RM with low tidal volume ventilation could lower significantly the injury of lung vascular endothelial diastole function in rats with acute lung injury.
ABSTRACT
Objective To observe the effects of recruitment maneuver (RM) and tidal volume with different amount of gas after RM ventilation on lung diastole function in rats with acute lung injury (ALI). Method ALI rat models were induced by intravenous infusion of lipopolysaccharide (LPS) in dose of 6 mg/kg. Twenty-five rats were randomly(random number) divided into control group ( n = 5), ALI group ( n = 5), low tidal volume group (LV group,VT= 6 mL/kg, n = 5), sustained inflation (SI) with low tidal volume (SI+ LV group, VT=6 mL/kg, n = 5), and SI with moderate tidal volume group (SI+ MV group, VT= 12 mL/kg, n = 5). The RM carried out by using SI with airway pressure 30 cmH-2O for 30 seconds, and the positive end-expiratory pressure (PEEP)was set at 5 cmH2O. Lung tissue was taken after mechanical ventilation for 5 hours. The mean arterial pressure (MAP) was monitored throughout the entire course of experiment. Endothelin-1 ( ET-1 ), endothelial nitricoxide synthase (eNOS), and acetylcholine-(Ach-) induced endothelium-dependent relaxation response of isolated pulmonary artery rings were investigated after mechanical ventilation for 5 hours. Results The LPS increased the ET-1 level in lung tissue, decreased the level of eNOS in lung tissue, and impaired the Ach-induced endothelium-dependent relaxation response in pulmonary vassals, without obvious influence on systemic hemodynamics. SI + LV significantly reduced LPS-induced elevation of ET-1 level, and increased the level of eNOS, and significantly lessened endothelial dysfunction and ameliorated dysfunction od endothelium-dependent relaxation in pulmonary vas sals. Conclusions RM with high tidal volume or lowtidal volume ventilation could improve the lung vascular endothelial function of rats with acute lung injury, and RM with low tidal volume ventilation could lessen more the injury of lung vascular endothelial diastole function in rats with acute lung injury.
ABSTRACT
Objective To study the therapeutic and protective effect of low tidal volume(LTV) ventilation in children with acute respiratory failure.Methods Forty-eight patients with respiratory failure were enrolled in our study.The patients were suffered from severe infection,trauma or after major operation.Besides general treatments,they were all given ventilation with LTV.Blood gas,ventilation parameters and complications related to ventilation were also measured.Results No significant difference was found between the patients with high tidal volume(HTV) and those with LTV in the results of improving respiratory acidosis.But the incidence of(ventilated-)induced lung injury(VILI) was lower in LTV patients.Conclusion LTV ventilation is preferable for children with acute respiratory failure and beneficial for alleviation of VILI.
ABSTRACT
Mechanical ventilation plays a central role In the critical care setting; but its use is closely related with some life threatening complications as nosocomial pneumonia and low cardiac performance. One of the most severe complications is called ventilator-associated lung injury (VALI) and it includes: Barotrauma, volutrauma, atelectrauma, biotrauma and oxygen-mediated toxic effects and it is related with an inflammatory response secondary to the stretching and recruitment process of alveoli within mechanical ventilation. The use of some protective ventilatory strategies has lowered the mortality rate 10% approximately.
La importancia de la asistencia mecánica ventilatoria (AMV) en la Unidad de Cuidados Intensivos (UCI) es indiscutible; sin embargo, su uso está ligado con complicaciones como neumonía nosocomial y deterioro del rendimiento cardiaco, que en algunas ocasiones ponen en peligro la vida del enfermo. Una de las complicaciones más graves es el daño pulmonar asociado a la ventilación mecánica (DPVM). El DPVM se caracteriza por la presencia de edema pulmonar rico en proteínas. Se recomienda establecer cierto número de estrategias de protección pulmonar (EPP) para prevenir este tipo de lesión. Una vez instituidas, las EPP han demostrado una disminución de la mortalidad de aproximadamente 10%.
Subject(s)
Animals , Humans , Rats , Barotrauma/etiology , Lung Injury , Respiration, Artificial/adverse effects , Acute Disease , Airway Resistance , Barotrauma/prevention & control , Clinical Trials as Topic , Dilatation, Pathologic/etiology , Dilatation, Pathologic/prevention & control , Elasticity , Hemodynamics/physiology , Oxidative Stress , Oxygen Inhalation Therapy/adverse effects , Oxygen/adverse effects , Positive-Pressure Respiration/adverse effects , Pressure/adverse effects , Pulmonary Alveoli/physiopathology , Pulmonary Edema/etiology , Pulmonary Edema/pathology , Pulmonary Edema/prevention & control , Respiration, Artificial/methods , Stress, MechanicalABSTRACT
Objective To compare the efficacy of mechanical ventilation (MV) with low tidal volume (LTV) plus positive expiratory end pressure (PEEP) and conventioal MV in the treatment of traumatic acute respiratory distress syndrome(ARDS). Methods From Oct 1997 to Oct 2003, 26 cases of traumatic ARDS patients were treated by conventioal MV(group A, n=11) or MV with LTV plus PEEP(group B,n=15), and clinical data of the patients were recorded and compared. Results There were no statistical difference in the PaO 2 of blood gas analysis and hemodynamic indices between the two groups, while the PaCO 2 was higher in group B than that in group A(P
ABSTRACT
Objective To investigate the effects of low tidal volume ventilation on pulmonary and cardiac function before and after mitral valve replacement. Methods Thirty patients with mitral valve diseases were randomly divided into traditional tidal volume ventilation (groupⅠ), low tidal volume ventilation with conventional respiratory rate (group Ⅱ), and low tidal volume ventilation with high respiratory rate (group Ⅲ). Mean arterial pressure (MAP), cardiac output(CO), cardiac index(CI), mean pulmonary arterial pressure (MPAP), pulmonary capillary wedge pressure (PCWP), central venous pressure (CVP), systemic vascular resistance index (SVRI), and pulmonary vascular resistance index (PVRI) were monitored. Arterial oxygen tension (PaO_2), carbon dioxide tension (PaCO_2), oxygen saturation index(PaO_2/FiO_2), alveolar-arterial PO_2 gradient (PA-aO_2), and Q_S/Q_T were measured. Results Before CPB, CO in group Ⅰ was significantly lower than that in group Ⅲ (P