Objective To evaluate the influence of tidal volume on the accuracy of stroke volume variation ( SVV) to predict volume state of pigs with ventilation.Methods Thirty-six healthy pigs were anesthetized after tracheal intubation and ventilated. With the envelope method, they were randomized into a normovolemia group, a hemaerrhagic shock group, and a hypervolemia group, with 12 pigs in each group. The pigs in the hemaerrhagic shock group were removed 20 percent of blood, and the pigs in the hypervolemia group received additional infusion of 20 percent 6% hydroxyethyl starch. In each group, ventilator settings were changed in a randomized order by changing VT [ VT = 5 mL/kg ( VT5 ) , VT =10 mL/kg ( VT10 ) , and VT =15 mL/kg ( VT15 ) ] . Hemodynamic measurements [ heart rate ( HR) , mean arterial boold pressure ( MAP) , systemic vascular resistance index ( SVRI) , cardiac index ( CI) , stroke volume index ( SVI) , intrathoracic blood volume index( ITBVI) , and SVV] were obtained after 10 minutes of stabilization. Results SVV was increased in the hemaerrhagic shock group comparing with the normovolemia group for VT10 [ ( 21 ±5) % vs. ( 11 ±2) % , P lt;0. 05] , but SVV was decreased in the hypervolemia group comparing with the normovolemia group [ ( 7 ±2) % vs. ( 11 ±2) % , P lt; 0. 05] . The variation tendency for VT15 was the same with VT10 , moreover SVV were all above 12% for the hemaerrhagic shock group, the normovolemia group, and the hypervolemia group [ ( 30 ±7) % , ( 19 ±3) % , and ( 15 ±4) % ] . There were no significant diffrences among the hemaerrhagic shock group, hypervolemia group and normovolemia group [ ( 8 ±6) % ,( 7 ±5) % , and ( 7 ±4) % , P gt; 0. 05] for VT5 . Conclusions SVV was a precise indicator of cardiac preload, but SVV was less sensitive to the changes of volume during low tidal volume ( 5 mL/kg) ventilation. The threshold of SVV for predicting fluid responsiveness maybe above 12% with a high tidal volume ( 15 mL/kg) ventilation.
Objective To investigate the dynamic changes of postoperative liver reserve function and laboratory liver function as well as liver volume regeneration, and their potential relationship with short-term clinical outcomes after adult-to-adult living donor liver transplantation (LDLT). Methods The data of 30 recipients underwent LDLT were prospectively collected. The plasma clearance (K) by indocyanine green (ICG) excretive test, liver function test by laboratory methods, liver volume by CT and shortterm (lt;3 months) complications were analyzed. Results The graft recipient body weight ratio (GRBW) was 0.63%-1.43%. The hepatic volume of the recipients in the operation was (638±103) ml, which was smaller than that day 7, 30, and 90 after operation (Plt;0.001), but the hepatic volume at subsequent time point was not different from that at the former time point (Pgt;0.05). The KICG values of recipients among the day 3 〔(0.177±0.056)/min〕, 7 〔(0.183±0.061)/min〕, 30 〔(0.200±0.049)/min〕, and 90 〔(0.209±0.050)/min〕 after operation gradually increased, which was respectively higher than that of recipients before operation (P=0.006, P=0.002, Plt;0.001, and Plt;0.001). Compared with the baseline KICG 〔(0.228±0.036)/min〕 of the donors, the KICG of recipients showed significant variation on day 3 and 7 after operation (P=0.004 and P=0.015), and the KICG of recipients on day 30 and 90 after operation approached the baseline KICG (P=0.355 and P=0.915). The recipients were divided into good liver function group (n=23) and poor liver function group (n=7) according to total serum bilirubin on day 14 after operation. The KICG significantly dropped compared with the recipients of good liver function group on day 3 after operation (P=0.001). Conclusions The liver volume regenerates dramatically on day 7 after operation for the recipients. The ICG excretivetest shows that volume recovery occurs much more gradually than the recovery of function in the recipients. The ICG excretive test is a more reliable indicator of graft function and subsequent graft outcome early after LDLT.
Objective To investigate the therapeutic effects of biphasic positive airway pressure (Bilevel) ventilation and volume ventilation plus [VV+，including volume control plus (VC+) and volume support (VS)] on respiratory failure in patients with chronic obstructive pulmonary disease (COPD).Methods 63 patients with COPD complicated by acute respiratory failure were intubated and underwent mechanical ventilation for at least 24 hours.At the first patients were underwent assist-control (A/C) ventilation for 2 to 4 hours to obtain the suitable basic ventilatory parameters.Meanwhile，the hemodynamics and oxygen dynamic parameters were measured.Then the patients were randomly allocated to three groups with 21 patients in each group and the ventilation mode was switched to Bilevel，VC+ and A/C mode correspondingly.The setting parameter was identical in three modes.In the process of weaning，patients in Bilevel group were ventilated with Bilevel and pressure support ventilation (PSV) mode at each pressure level，and subdivided into Bilevel and PSV 1 group accordingly.In VC+ group，the mode was switched to VS and PSV mode and subdivided into VC+ group and PSV 2 group,respectively.Every mode was run for 30 minutes while the ventilation function，blood gas exchange and lung mechanics index were measured.Results In the initial stage，the airway peak pressure (PIP) of Bilevel and VC+ mode obviously decreased，and the respiratory compliance was higher compared to the A/C mode. The effectiveness of Bilevel and A/C was equivalent in improving alveolar ventilation and oxygenation.The difference in the change of circulation function and blood gas between the two groups were not significant (Pgt;0.05).In the process of weaning，the effectiveness of Bilevel and VV+ was equal to PSV.The changes of breathing mode and blood gas between the two groups had no significant differences.Conclusions Bilevel and VV+ mode ventilation can be used in the whole mechanical ventilation for acute respiratory failure due to COPD with lower PIP，higher respiratory compliance compared to A/C model and similar performance as PSV during mechanical ventilation withdrawn.
ObjectiveTo explore the mechanism of volume-related mitral regurgitation (MR) from the anatomy of mitral valve.MethodsA total of 32 patients with ventricular septal defect (VSD) combined MR meeting inclusion criteria in West China Hospital from September 2018 to November 2019 were enrolled in this study. The direction relative to the cardiac axis: the deviation of the MR bundle along the left atrial wall was eccentric, otherwises it was central. There were 23 patients of VSD and eccentric MR (EMR, a VSD-EMR group), including 10 males and 13 females aged 21 (10, 56) months, and 9 patients of VSD and central MR (CMR, a VSD-CMR group), including 4 males and 5 females aged 26 (12, 87) months. Besides, 9 healthy children were enrolled in a control group, including 4 males and 5 females aged 49 (15, 72) months. All patients underwent transthoracic echocardiography (TTE) examination at 2 weeks before surgery and 6 months after surgery, respectively, The MR degree, end-diastolic volume (EDV), end-systolic volume (ESV), stroke volume (SV), ejection fraction (EF), antero-posterior diameter (AP), annulus circumference (AC), commissural diameter (CD) were assessed.ResultsBefore operation, EDV, ESV, SV, AP, AC and CD in the VSD-EMR and VSD-CMR groups were significantly larger or longer than those in the control group (P<0.05); after operation, EDV, ESV, SV, AP and CD decreased compared with those before operation (P<0.05), but there was no significant difference compared with the control group (P>0.05). Compared with the control group, AC was slightly decreased (P<0.05). There was no significant difference in EF between and within groups before and after operation (P>0.05). The improvement rate of MR was 78.9% (15/19) in the VSD-EMR group and 100.0% (9/9) in the VSD-CMR group.ConclusionAfter unloading of volume, the valve structure is back to normal except AC. The improvement rate of MR in the VSD-EMR group is lower than that in the VSD-CMR group, which may indicate that the mechanism of VSD-EMR is more complicated.
ObjectiveTo compare the dosimetric differences among flattening filter free intensity modulated radiotherapy (3FIMRT), flattening filter free volumetric modulated arc therapy (3FVMAT), filter free intensity modulated radiotherapy (IMRT), and filter free volumetric modulated arc therapy (VMAT) for hyperthyroidism exophthalmus patients.MethodsComputed tomography (CT) scans of 29 patients, who were diagnosed with hyperthyroidism exophthalmus and treated with radiation therapy between September 2016 and September 2017, were selected for study. Four treatment plans with the same dose prescription and objective constrains were designed for each patient based on their images, consisting of IMRT, VMAT, 3FIMRT, and 3FVMAT. The target dosimetric distribution, normal tissue radiation dose, monitor units, and treatment time of each plan were evaluated.ResultsFour types of plans were all able to satisfy the clinical treatment requirements, and there were no significant differences in maximum dose, mean dose (Dmean), homogeneity index of the targets (P>0.05). For the parameters minimum dose, V50%, conformity index (CI), gradient index of the targets, statistically significant differences were observed among the four kinds of technologies (F=10.920, 35.860, 11.320, 17.790; P<0.05). The CI of IMRT and 3FIMRT were superior to those of VMAT and 3FVMAT, but there was no significant difference between IMRT and 3FIMRT. In terms of Lens Dmean and Brain Dmean, statistically significant differences were observed among the four kinds of technologies (F=5.054, 83.780; P<0.05). For Lens Dmean and Brain Dmean, 3FVMAT achieved better sparing effects when compared with the other three plans. The total monitor units and treatment time did not significantly differ between 3FVMAT and VMAT. The mean monitor units of 3FVMAT were 65.07% and 70.22% less than that of IMRT and 3FIMRT respectively. The mean treatment time of 3FVMAT were 48.1% and 35.24% less than that of IMRT and 3FIMRT respectively.Conclusion3FVMAT can bring more dosimetric advantages for hyperthyroidism exophthalmus radiation therapy when compared with IMRT, 3FIMRT, and VMAT.
Objective To investigate the effect of bilevel ventilation mode on blood gas and hemodynamics of patients with acute lung injury (ALI) by pulse indicator continuous cardiac output(PiCCO), and the clinical effect of this new ventilation mode on patients with ALI as well as its influence degree of circulatory system so that the cure rate of ALI can be improved. Methods There were 42 patients with ALI, 27 male and 15 female aged 15-75 years. According to the order of hospitalization, 40 patients (2 patients did not complete the study) were divided into two groups with 20 patients in each group. Bilevel ventilation group included the first 20 admitted patients. They were given bilevel ventilation support, using Support/Time(S/T) mode. The initial set of end inspiratory pressure (IPAP) was 8-10 cm H2O gradually increased to 14-20 cm H2O, which should be comfortable and appropriate for patients. The initial set of end expiratory pressure (EPAP) was 3-5 cm H2O gradually increased to 8-12 cm H2O. Fraction of inspired oxygen(FiO2) unchanged. Control group included the rest 20 admitted patients. They were given respiratory support, using Auxiliary/Control(A/C) mode followed by an increased positive endexpiratory pressure (PEEP) of 5 cm H2O,10 cm H2O,15 cm H2O,20 cm H2O. Each pressure kept 30 min. FiO2 unchanged. Indexes such as cardiac output (CO), systemic vascular resistance (SVR) etc were observed in both groups. Results There were 13 deaths in two groups, including 5 in bilevel ventilation group and 8 in control group. Seven cases died of multiple organ failure, 3 died of septic shock and 3 died of circulatory failure. Endotracheal intubation time (2.9±0.8 d vs. 4.2±0.9 d, t=7.737, P=0.006) and hospital stay (17.2±4.5 d vs. 18.5±3.6 d, t=2.558, P=0.039) in bilevel ventilation group were significantly shorter than those in control group. In control group, when PEEP ranged from 5 cm H2O to 15 cm H2O, arterial partial pressure of oxygen (PaO2) and oxygenation index (PaO2/FiO2) gradually increased as PEEP increased (Plt;0.05); when PEEP increased to 20 cm H2O, CO decreased, SVR, pulmonary vascular resistance (PVR) and airway peak pressure (PIP) increased than those in range of 515 cm H2O (Plt;0.05). In bilevel ventilation group, PaO2 and PaO2/FiO2 gradually increased as EPAP increased. When EPAP increased to 10 cm H2O, PaO2 and PaO2/FiO2 increased to the maximum (Plt;0.05); PIP was significantly lower than that in control group (t=7.831, .P.=.0.000). Conclusion Giving bilevel ventilation treatment to patients with ALI/acute respiratory distress syndrome(ARDS) can reduce the effects on respiratory and hemodynamic. PIP and the time of endotracheal intubation and hospital stay can be reduced without affecting hemodynamics.
Objective To investigate the consistency of regions of interest (ROI) volume among different radiological treatment planning systems (TPS) for the same group of patient data, and analyze the tendency and degree of differences caused by data transfer. Methods Between October 2010 and December 2013, the data of 10 nasopharyngeal carcinoma patients treated in West China Hospital were transferred from Monaco TPS into various other treatment planning systems. Based on different ROI volumes, they were divided into 8 groups. We counted the volume differences between these TPS and Monaco TPS, and carried out the statistical analysis. Results For small ROI volume, the calculated difference reached up to 65% in our study. As a general trend, differences became less and less with the increasing of volumes. But for single ROI, the volume difference was likely to vary randomly. The percentage of ROI volumes which were smaller than that of Monaco TPS was 70% for Raystation TPS, 38.75% for Pinnacle TPS, 88.75% for Eclipse TPS, 97.5% for Masterplan TPS, and 83.13% for iPlan TPS. Conclusions ROI volume differences exist generally among different treatment planning systems when ROIs are transferred among them by DICOM protocol. The volume variations may be affected by multiple factors. The volume consistency should be evaluated before any direct comparison of dose volu me histogram parameters which are done between different systems.
Objective To explore the correlation between liver volume variation of posthepatitic cirrhosis patients and the severity of the disease. Methods One hundred and eleven patients with normal livers and 74 posthepatitic cirrhosis patients underwent volume CT scan. The relation between normal liver volume and body height, body weight and body surface area was studied by linear regression and correlation method, the standard liver volume equation was deduced. The change ratio of liver volume in cirrhotic patients was calculated and compared with Child classification. Results The mean normal liver volume of Chinese adults was （1 225.15±216.23） cm3, there was a positive correlation between liver volume and body height, body weight 〔liver volume (cm3)=12.712×body weight (kg)+450.44〕 and body surface area 〔liver volume (cm3)=876.02×body surface area (m2)-297.17〕. The mean liver volume of Child A, B and C patients were （1 077.77±347.01） cm3, (1 016.35±348.60) cm3 and (805.73±208.85) cm3 respectively. The liver volume and liver volume index was significantly smaller in Child C patients than those in Child A and B patients (P＜0.05); while liver volume change ratio was higher in Child C patients (P＜0.05). Conclusion Liver volume variation of cirrhotic patients can be quantitatively assessed by 16 slices helical CT volume measurement and standard liver volume equation. The change of the liver volume is correlated with the severity of liver cirrhosis.
ObjectiveCompare the two-degrade collimator (MLC) angle selection's impact on plan quality and operational efficiency for volumetric intensity-modulated radiotherapy (VMAT) in the treatment planning system, and to explore the scheme for treatment plan optimization. MethodsTwenty patients with nasopharyngeal carcinoma underwent the treatment between March and December 2013 were randomly selected and planned for SIBVMAT treatment with different parameters set in the range of 0-60°with 15°interval for collimator angles. Planned dose distribution to the target volumes, organs at risk, and monitor units were compared. ResultsAs the MLC angle increased, target conformal index and homogeneity index had a trend to became deteriorated. The optimal plans were 0°and 15°, while 45°and 60°plans gave poor protection for the organ at risk compare to other angle plans and the monitor units were significantly increased. ConclusionChange the MLC angle had visible impact on treatment plans,there was a trend to deteriorate with the MLC angle increased, but small changes in MLC angle range can theoretically reduce the influence from leakage radiation on the human body.
Volume-targeted ventilation has been widely used in neonates requiring mechanical ventilation in recent years. However, as a novel method, its application involves risks. Based on domestic and international evidence, we developed a guideline for the use of volume-targeted ventilation in neonatal respiratory support using the grading of recommendations for assessment, development and evaluation of evidence (GRADE) method, to help neonatal healthcare professionals standardize the use of volume target ventilation.