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.
ObjectiveTo investigate the effect of pressure control ventilation-volume guaranteed (PCV-VG) for patients undergoing da Vinci robotic-assisted pulmonary lobotomy.
MethodA total of 40 patients undergoing Da Vinci robotic-assisted pulmonary lobotomy were randomly divided into two groups:a PCV-VG group (G group) and a volume-controlled ventilation (VCV) group (V group). There were 20 patients in each group with 13 males and 7 females at age of 49.0±5.5 years in the G group, 16 males and 4 females at age of 51.0±3.9 years in the V group. Haemodynamics indexes and oxygenation parameters were recorded at different times and compared between the two groups.
ResultsDuring one-lung ventilation (OLV) period, the peak inspiratory pressure (Ppeak), respiratory index (RI) and arterial partial pressure of carbon dioxide (PaCO2) in the G group were statistically lower than those in the V group (P<0.05). While the Cdyn and inspired oxygen fraction(OI) were higher in the G group than those in the V group (P<0.05).
ConclusionCompared with the traditional VCV ventilation mode, the PCV-VG ventilation mode improves Ppeak, Cdyn, OI, and RI of the patients undergoing da Vinci robotic-assisted pulmonary lobotomy.
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.
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.
ObjectiveTo observe the predictive value of Volume OXygeneration (VOX) index for early non-invasive positive pressure ventilation (NIPPV) treatment in patients with type I Respiratory failure. MethodsRetrospective analysis was made on the patients with type I Respiratory failure admitted to the intensive care medicine from September 2019 to September 2022, who received early NIPPV treatment. After screening according to the discharge standard, they were grouped according to the NIPPV 2-hour VOX index. The observation group was VOX Youden index >20.95 (n=69), and the control group was VOX index ≤20.95 (n=64). Collect patient baseline data and NIPPV 2-hour, 12-hour, and 24-hour arterial blood gas values, and calculate NIPPV outcomes, intubation status, NIPPV usage time, hospital stay, and mortality rate. ResultsThere was a statistically significant difference in respiratory rate (RR) between the baseline data onto the two groups of patients, but others not. After early NIPPV treatment, the 2-hour oxygenation index (P/F) [(182.5 ± 66.14) vs. (144.1 ± 63.6) mm Hg, P<0.05] of the observation group showed a more significant increase. The failure rate of NIPPV intubation within 12 hours was lower (4.35% vs. 32.81%, P<0.05), the success rate of NIPPV withdrawal from 24 hours was higher (40.58% vs. 0%, P<0.05), and the failure rate of NIPPV intubation was lower (4.35% vs. 46.88%, P<0.05). The comparison of treatment outcomes showed that the intubation rates in the observation group (4.35% vs. 67.19%, P<0.05) was lower. The threshold of NIPPV 2-hour VOX index 20.95 was used as a predictor of Tracheal intubation, with sensitivity of 74.7% and specificity of 93.5%. ConclusionIn the early NIPPV treatment of patients with type I Respiratory failure, the NIPPV 2-hour VOX index>20.91 is taken as the evaluation index, which can better to predict the improvement in hypoxia and the risk of NIPPV failure Tracheal intubation, and has clinical significance.
Simulation of the human biological lung is a crucial method for medical professionals to learn and practice the use of new pulmonary interventional diagnostic and therapeutic devices. The study on ventilation effects of the simulation under positive pressure ventilation mode provide valuable guidance for clinical ventilation treatment. This study focused on establishing an electrical simulation ventilation model, which aims to address the complexities in parameter configuration and slow display of air pressure and airflow waveforms in simulating the human biological lung under positive pressure ventilation mode. A simulated ventilation experiment was conducted under pressure-regulated volume control (PRVC) positive pressure ventilation mode, and the resulting ventilation waveform was compared with that of normal adults. The experimental findings indicated that the average error of the main reference index moisture value was 9.8% under PRVC positive pressure ventilation mode, effectively simulating the ventilatory effect observed in normal adults. So the established electrical simulation ventilation model is feasible, and provides a foundation for further research on the simulation of human biological lung positive pressure ventilation experimental platform.
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.
ObjectiveTo discuss the application value of the two kinds of three dimensional reformatting techniques of spiral CT: volume rendering (VR) and maximum intensity projection (MIP) in the evaluation of children's skeletal abnormality.
MethodsEighteen children with skeletal abnormality in our hospital treated between March and June 2014 were recruited in this study, diagnosed by CT transversal images and images of multiplanar reformatting (MPR). VR and MIP were made with the raw data. All three dimensional images were independently evaluated by two doctors of the Radiology Department (a score of 1-4). Images with a score of 4 were excellent. Wilcoxon signed ranks test was done for all scores and Kappa values were calculated.
ResultsImages score of VR was 3.28±0.96 and of MIP was 2.89±0.90, without statistically significant difference (Z=-1.732, P=0.125). Kappa value of VR was 0.730 and of MIP was 0.593, with good and moderate consistency.
ConclusionWith the special superiority of displaying spatial configuration, VR and MIP can be used to help two dimensional CT images to evaluate children's skeletal abnormality more comprehensively.
ObjectiveTo study the model to predict thymus volume with two-dimensional section diameters among fetuses.
MethodsFrom September 2010 to March 2012, 210 singleton pregnant women suspected with fetal abnormality by prenatal ultrasonic testing were confirmed using MRI technology. Three two-dimensional section diameters of thymus were measured and the volume was calculated. No abnormal fetuses regarded as the standard, theoretical normal volume of fetal thymus was calculated. Paired t-test was used to compare the actual thymus volume with its corresponding theoretical normal value, and thus the fetuses were divided into two groups of normal and dysplasia so as to establish predictive model respectively. With two-dimensional section diameters as independent variables and thymus volume as dependent variable, the linear regression model was established. According to the model, the thymus volume was predicted and the error rate was calculated by formula: error rate=(predicted value-actual value) /actual value×100%. The Pearson correlation coefficient of error rate and fetal gestational age was calculated.
ResultsThe models of normal and dysplasia groups to predict thymus volume were lnV=0.016d1+0.030d2+0.086d3+5.707+ε (R2=0.510) and lnV=0.048d1+0.036d2+0.016d3+6.011+ε (R2=0.447). The average absolute values of predicted error rate were 4.34% and 5.34% and decreased with fetal gestational age (normal r=-0.264, P=0.007; dysplasia r=-0.182, P=0.060).
ConclusionThe prediction effects of above models are not so good and the model accuracy increases with fetal gestational age. Normal fetuses' model of different gestational age should be established to predict thymus volume by conducting large sample size study in the future. The modeling approach has certain practicability and clinical value and can be applied in ultrasonic technique.
