Pressure-support ventilation (PSV) is a form of important ventilation mode. Patient-ventilator synchrony of pressure support ventilation can be divided into inspiration-triggered and expiration-triggered ones. Whether the ventilator can track the patient's inspiration and expiration very well or not is an important evaluating item of the performance of the ventilator. The ventilator should response to the patient's inspiration effort on time and deliver the air flow to the patient under various conditions, such as different patient's lung types and inspiration effort, etc. Similarly, the ventilator should be able to response to the patient's expiration action, and to decrease the patient lung's internal pressure rapidly. Using the Active Servo Lung (ASL5000) respiratory simulation system, we evaluated the spontaneous breathing of PSV mode on E5, Servo i and Evital XL. The following parameters, the delay time before flow to the patient starts once the trigger variable signaling the start of inspiration, the lowest inspiratory airway pressure generated prior to the initiation of PSV, etc. were measured.
ObjectiveTo analyze the clinical characteristics and related prognostic factors of post-renal transplantation pneumonia.MethodsThe clinical data of 89 patients with post-renal transplantation pneumonia in Sichuan Academy of Medical Sciences & Sichuan Provincial People’s Hospital from 1st January 2014 to 31st December 2015 were collected in the study. Kaplan-Meier method was used to calculate overall survival. Cox analysis was used to analyze the related prognostic factors.ResultsPost-renal transplantation pneumonia occurred mainly within 6 months after renal transplantation. The prominent clinical manifestations were cough (95.5%), fever (56.1%), and dyspnea (12.3%). The mortality of post-renal transplantation pneumonia was 11.2% and all death occurred within 5 months after transplantation. The overall survival rate significantly decreased in the patients with C-reactive protein (CRP) ≥40 mg/L (P<0.001), procalcitonin ≥1 ng/ml (P=0.002), brain natriuretic peptide >100 pg/ml (P<0.001), platelet ≤100×109/L (P<0.001), or those with occurrence time of pneumonia <180 days (P=0.013). Platelet ≤100×109/L could increase the risk of death by 66.6 times (RR=0.015, P=0.006), and CRP ≥ 40 mg/L could increase the risk of death by 20 times (RR=0.05, P=0.029).ConclusionsPost-renal transplantation pneumonia has prominent clinical characteristics. Platelet ≤100×109/L or CRP ≥40 mg/L can increase the risk of death and can be used as an independent prognoctic factor of post-renal transplatation pneumonia.
Forced oscillation technique (FOT) is an active method to test pulmonary function, which can derive the mechanical characteristics of the respiratory system with liner system identification theory by pushing in an oscillation air signal and measuring the changes of output pressure and flow. A pulmonary function determination system was developed based on the FOT in this paper. Several critical technologies of this determination system were analyzed, including the selection criteria of oscillation air generator, pressure and flow sensor, the signal design of oscillation air generator, and the synchronous sampling of pressure and flow data. A software program on LabVIEW platform was set up to control the determination system and get the measuring data. The performance of sensors and oscillation air generator was verified. According to the frequency response curve of the pressure, the amplitude of driving signal to the oscillation air generator was corrected at the frequency range between 4~40 Hz. A simulation experiment was carried out to measure the respiratory impedance of the active model lung ASL5000 and the results were close to the setting values of the model lung. The experiment testified that the pulmonary function determination system based on FOT had performance good enough to provide a tool for the in-depth research of the mechanical properties of the respiratory system.
Objective To investigate HCV genotypes in HCV patients in West China Hospital of Sichuan University, and to analyze the major genotypes and clinical characteristics. Methods From March 2011 to September 2016, 4 520 HCV patients who were successfully genotyped HCV genotypes were enrolled in West China Hospital of Sichuan University. The genotypes distributions and the characteristics of laboratory characteristics of liver function, the viral loading were all analyzed. In addition, the genotypes in HCC patients, liver cirrhosis, HBC/HCV co-infection were also analyzed. Results HCV genotypes of HCV patients were divided into five genotypes of 1, 2, 3, 4, 6 and 23 subtypes, including predominant genotypes/subtypes 1b, 1*, 3b, 2a, 3a and 6a, accounting for 66.42%, 8.01%, 6.57%, 4.54%, 4.29%, and 3.41%, respectively. Subtype 1b was the predominant subtype for both sex. In male patients, the levels of ALT were highest in 6a subtype, while in female, the levels of ALT were highest in 3a subtype. For the 94 liver cirrhosis patients, 42 patients were 1b subtypes; as for the 6 HCC patients, 1b and 3b subtypes were the only detected. Conclusion HCV genotypes/subtypes of HCV patients in West China Hospital of Sichuan University have unique characteristics of distribution, while the predominant genotype/subtypes are 1b,1*, 3b, 2a, 3a, 6a.
ObjectiveTo analyze hepatitis B virus (HBV) genotype distribution and drug-resistant mutations in West China Hospital of Sichuan University, providing basis for hepatitis B individualized treatment.MethodsA total of 786 chronic hepatitis B patients admitted to West China Hospital of Sichuan University from January 2016 to December 2018 were enrolled in the study. Genotype and drug-resistant mutations were analyzed by Sanger sequencing, and statistical analysis was conducted by χ2 test.ResultsThree genotypes (B, C and D) were identified in 786 samples, 489 (62.2%) in genotype B, 291 (37.0%) in genotype C , and 6 (0.8%) in genotype D. The distribution differences of B and C genotypes in age and ethnic groups were statistically significant (P<0.05). Among them, 627 cases had drug-resistant mutations, with a drug-resistant mutation rate of 79.8%. A total of 262 cases (33.3%) were resistant to lamivudine and tibivudine, 102 cases (13.0%) were resistant to lamivudine, tibivudine and entecavir; 83 cases (10.6%) were resistant to adefovir dipivoxil. No tenofovir resistant strains were detected in 786 samples. There were statistically significant differences in drug resistance between B and C genotypes (χ2=14.356, P<0.01). The most common single mutation was M204I [179 cases (22.8%)], followed by 46 cases (5.9%) of A181V/T associated with adefovir dipivoxil resistance. The most common mixed mutation was L180M+M204V/I in 83 cases (10.6%), and another 102 cases (13.0%) showed M250V and/or V173L and/or T184A/G/S/I and/or S202G/I with L180M+M204V/I.ConclusionsHBV genotypes in West China Hospital of Sichuan University are mainly B and C, and the situation of drug resistance is severe and the mutation pattern is complex. Therefore, detecting HBV genotype and drug resistance mutation is necessary, which may develop better clinical treatments.
Correlation between nonlinear subharmonic scattering of ultrasound contrast agent microbubbles and ambient pressure is expected to be used for local brain tissue pressure monitoring. Although high-frequency ultrasound has achieved high-resolution imaging of intracranial microvessels, the research on high-frequency subharmonic scattering characteristics of microbubbles is insufficient at present, which restricts the research progress of estimating local brain tissue pressure based on high-frequency subharmonic scattering of microbubbles. Therefore, under the excitation of 10 MHz high-frequency ultrasound, the effects of different acoustic pressures and ambient pressures on the high-frequency subharmonic scattering characteristics of three different ultrasound contrast agents including SonoVue, Sonazoid and Huashengxian were investigated in this in vitro study. Results showed that the subharmonic scattering amplitudes of the three microbubbles increased with the increase of ambient pressure at the peak negative acoustic pressures of 696, 766 and 817 kPa, and there was a favorable linear correlation between subharmonic amplitude and ambient pressure. Under the above three acoustic pressures, the highest correlation coefficient of SonoVue was 0.948 (P = 0.03), the highest sensitivity of pressure measurement was 0.248 dB/mm Hg and the minimum root mean square error (RMSE) was 2.64 mm Hg. Sonazoid's highest correlation coefficient was 0.982 (P < 0.01), the highest sensitivity of pressure measurement was 0.052 dB/mm Hg and the minimum RMSE was 1.51 mm Hg. The highest correlation coefficient of Huashengxian was 0.969 (P = 0.02), the highest sensitivity of pressure measurement was 0.098 dB/mm Hg and the minimum RMSE was 2.00 mm Hg. The above in vitro experimental results indicate that by selecting ultrasound contrast agent microbubbles and optimizing acoustic pressure, the correlation between high-frequency subharmonic scattering of microbubbles and ambient pressure can be improved, the sensitivity of pressure measurement can be upgraded, and the measurement error can be reduced to meet the clinical demand for local brain tissue pressure measurement, which provided an important experimental basis for subsequent research in vivo.
ObjectiveTo explore the application value of plasma Epstein-Barr virus (EBV) DNA test in the clinical diagnosis of patients with nasopharyngeal carcinoma in non-high-incidence areas of Southwest China and its significance for monitoring patients after treatment. MethodsA total of 235 patients diagnosed with non-keratinized nasopharyngeal carcinoma between January 2014 and December 2015 were retrospectively collected. The plasma EBV-DNA test rate of the nasopharyngeal carcinoma patients before treatment, the positive rates of the plasma EBV-DNA test before treatment and within 6 months of treatment, and the relationship between the positivity of plasma EBV-DNA within 6 months of treatment and the prognosis of nasopharyngeal carcinoma were analyzed. ResultsThe plasma EBV-DNA test rate of the nasopharyngeal carcinoma patients before treatment was 69.79% (164/235), with a positive rate of 90.85% (149/164). A total of 131 patients were tested for EBV-DNA within 6 months of treatment, whose positive rate was 89.31% (117/131) before treatment and 21.37% (28/131) within 6 months of treatment, respectively, with a statistically significant difference (P<0.001). Comparing the prognosis of EBV-DNA positive patients and negative patients within 6 months of treatment, the difference in 3-year recurrence rate between the two groups was not statistically significant (10.71% vs. 3.88%, P=0.341); however, the 3-year metastasis rate (21.43% vs. 4.85%, P=0.016) and the 3-year disease progression rate (32.14% vs. 6.80%, P=0.001) of the EBV-DNA positive patients were higher than those of the EBV-DNA negative patients, and the log-rank test slao showed that the 3-year progression-free survival rate (67.86% vs. 93.20%, P<0.001) and the 3-year metastasis-free survival rate (78.57% vs. 95.15%, P=0.004) of the EBV-DNA positive patients were lower than those of the EBV-DNA negative patients. There was no statistically significant between-group difference in the 3-year progression-free survival curve when grouped by age, gender, or TNM staging (P>0.05).ConclusionsFor patients with non-keratinized nasopharyngeal carcinoma in non-high-incidence areas of Southwest China, EBV-DNA detection is important for the screening and diagnosis of nasopharyngeal carcinoma, and the positivity of EBV-DNA test within half a year of treatment is an important factor affecting the prognosis and progression of patients. Plasma EBV-DNA levels should be monitored regularly before and after treatment.