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.
ObjectiveTo evaluate the predictive value of mini-fluid challenge for volume responsiveness in patients under shock.MethodsSixty patients diagnosed as shock were included in the study. A 50 mL infusion of physiological saline over 10 seconds and a further 450 mL over 15 minutes were conducted through the central venous catheter. Cardiac output (CO), global end-diastolic volume index (GEDVI), central venous pressure (CVP) and extravascular pulmonary water index (EVLWI) were monitored by the pulse indicator continuous cardiac output monitoring. If the increase of CO after 500 mL volume expansion (ΔCO500) ≥10%, the patient was considered to be with volume responsiveness. The relevance between ΔCO50 and ΔCO500 was analyzed, and the sensitivity and specificity of the ΔCO50 were analyzed by receiver operating characteristic (ROC) curve.ResultsAfter 50 mL volume injection, the heart rate and systolic blood pressure of the two groups did not change obviously. The CVP of non-responders changed slightly higher than that of responders, but neither of them had obviously difference (P>0.05). The CO of responders had increased significantly (P<0.05) which was in accord with that after a further 450 mL volume injection. GEDVI and EVLWI did not change significantly (P>0.05). ΔCO50 and ΔCO500 were strongly correlated (r=0.706, 95%CI 0.677 - 0.891, P>0.05). The area under ROC curve for ΔCO50 was 0.814 (95%CI 0.707 - 0.922).ConclusionThe volume responsiveness of patients under shock can be predicted by mini-fluid challenge study which is related to normal volume expansion and it does not increase the risk of pulmonary edema.
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.
To investigate the γ pass rate limit of plan verification equipment for volumetric modulated arc therapy (VMAT) plan verification and its sensitivity on the opening and closing errors of multi-leaf collimator (MLC), 50 cases of nasopharyngeal carcinoma VMAT plan with clockwise and counterclockwise full arcs were randomly selected. Eight kinds of MLC opening and closing errors were introduced in 10 cases of them, and 80 plans with errors were generated. Firstly, the plan verification was conducted in the form of field-by-field measurement and true composite measurement. The γ analysis with the criteria of 3% dose difference, distance to agreement of 2 mm, 10% dose threshold, and absolute dose global normalized conditions were performed for these fields. Then gradient analysis was used to investigate the sensitivity of field-by-field measurement and true composite measurement on MLC opening and closing errors, and the receiver operating characteristic curve (ROC) was used to investigate the optimal threshold of γ pass rate for identifying errors. Tolerance limits and action limits for γ pass rates were calculated using statistical process control (SPC) method for another 40 cases. The error identification ability using the tolerance limit calculated by SPC method and the universal tolerance limit (95%) were compared with using the optimal threshold of ROC. The results show that for the true composite measurement, the clockwise arc and the counterclockwise arc, the descent gradients of the γ passing rate with per millimeter MLC opening error are 10.61%, 7.62% and 6.66%, respectively, and the descent gradients with per millimeter MLC closing error are 9.75%, 7.36% and 6.37%, respectively. The optimal thresholds obtained by the ROC method are 99.35%, 97.95% and 98.25%, respectively, and the tolerance limits obtained by the SPC method are 98.98%, 97.74% and 98.62%, respectively. The tolerance limit calculated by SPC method is close to the optimal threshold of ROC, both of which could identify all errors of ±2 mm, while the universal tolerance limit can only partially identify them, indicating that the universal tolerance limit is not sensitive on some large errors. Therefore, considering the factors such as ease of use and accuracy, it is suggested to use the true composite measurement in clinical practice, and to formulate tolerance limits and action limits suitable for the actual process of the institution based on the SPC method. In conclusion, it is expected that the results of this study can provide some references for institutions to optimize the radiotherapy plan verification process, set appropriate pass rate limit, and promote the standardization of plan verification.
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.
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 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 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.
ObjectiveTo investigate the risk factors of cement leakage in percutaneous vertebroplasty (PVP) for osteoporotic vertebral compression fracture (OVCF). MethodsBetween March 2011 and March 2012, 98 patients with single level OVCF were treated by PVP, and the cl inical data were analyzed retrospectively. There were 13 males and 85 females, with a mean age of 77.2 years (range, 54-95 years). The mean disease duration was 43 days (range, 15-120 days), and the mean T score of bone mineral density (BMD) was-3.8 (range, -6.7--2.5). Bilateral transpedicular approach was used in all the patients. The patients were divided into cement leakage group and no cement leakage group by occurrence of cement leakage based on postoperative CT. Single factor analysis was used to analyze the difference between 2 groups in T score of BMD, operative level, preoperative anterior compression degree of operative vertebrae, preoperative middle compression degree of operative vertebrae, preoperative sagittal Cobb angle of operative vertebrae, preoperative vertebral body wall incompetence, cement volume, and volume ratio of intravertebral bone cement to vertebral body. All relevant factors were introduced to logistic regression analysis to analyze the risk factors of cement leakage. ResultsAll procedures were performed successfully. The mean operation time was 40 minutes (range, 30-50 minutes), and the mean volume ratio of intravertebral bone cement to vertebral body was 24.88% (range, 7.84%-38.99%). Back pain was alleviated significantly in all the patients postoperatively. All patients were followed up with a mean time of 8 months (range, 6-12 months). Cement leakage occurred in 49 patients. Single factor analysis showed that there were significant differences in the volume ratio of intravertebral bone cement to vertebral body and preoperative vertebral body wall incompetence between 2 groups (P < 0.05), while no significant difference in T score of BMD, operative level, preoperative anterior compression degree of operative vertebrae, preoperative middle compression degree of operative vertebrae, preoperative sagittal Cobb angle of operative vertebrae, and cement volume (P > 0.05). The logistic regression analysis showed that the volume ratio of intravertebral bone cement to vertebral body (P < 0.05) and vertebral body wall incompetence (P < 0.05) were the risk factors for occurrence of cement leakage. ConclusionThe volume ratio of intravertebral bone cement to vertebral body and vertebral body wall incompetence are risk factors of cement leakage in PVP for OVCF. Cement leakage is easy to occur in operative level with vertebral body wall incompetence and high volume ratio of intravertebral bone cement to vertebral body.
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.