ObjectiveStudy how to quantify the bias of each study and how to estimate them. MethodIn the random-effect model, it is commonly assumed that the effect size of each study in meta-analysis follows a skew normal distribution which has different shape parameter. Through introducing a shape parameter to quantify the bias and making use of Markov estimation as well as maximum likelihood estimation to estimate the overall effect size, bias of each study, heterogeneity variance. ResultIn simulation study, the result was closer to the real value when the effect size followed a skew normal distribution with different shape parameter and the impact of heterogeneity of random effects meta-analysis model based on the skew normal distribution with different shape parameter was smaller than it in a random effects metaanalysis model. Moreover, in this specific example, the length of the 95%CI of the overall effect size was shorter compared with the model based on the normal distribution. ConclusionIncorporate the bias of each study into the random effects meta-analysis model and by quantifying the bias of each study we can eliminate the influence of heterogeneity caused by bias on the pooled estimate, which further make the pooled estimate closer to its true value.
The impulsive electroencephalograph (EEG) noises in evoked potential (EP) signals is very strong, usually with a heavy tail and infinite variance characteristics like the acceleration noise impact, hypoxia and etc., as shown in other special tests. The noises can be described by α stable distribution model. In this paper, Wigner-Ville distribution (WVD) and pseudo Wigner-Ville distribution (PWVD) time-frequency distribution based on the fractional lower order moment are presented to be improved. We got fractional lower order WVD (FLO-WVD) and fractional lower order PWVD (FLO-PWVD) time-frequency distribution which could be suitable for α stable distribution process. We also proposed the fractional lower order spatial time-frequency distribution matrix (FLO-STFM) concept. Therefore, combining with time-frequency underdetermined blind source separation (TF-UBSS), we proposed a new fractional lower order spatial time-frequency underdetermined blind source separation (FLO-TF-UBSS) which can work in α stable distribution environment. We used the FLO-TF-UBSS algorithm to extract EPs. Simulations showed that the proposed method could effectively extract EPs in EEG noises, and the separated EPs and EEG signals based on FLO-TF-UBSS were almost the same as the original signal, but blind separation based on TF-UBSS had certain deviation. The correlation coefficient of the FLO-TF-UBSS algorithm was higher than the TF-UBSS algorithm when generalized signal-to-noise ratio (GSNR) changed from 10 dB to 30 dB and α varied from 1.06 to 1.94, and was approximately equal to 1. Hence, the proposed FLO-TF-UBSS method might be better than the TF-UBSS algorithm based on second order for extracting EP signal under an EEG noise environment.
Objective To investigate the role of red cell distribution width ( RDW) in coronary artery diseases patients complicated with obstructive sleep apnea-hypopnea syndrome ( OSAHS) . Methods 134 coronary artery diseases patients who had at least one-vessel disease confirmed by coronary angiography were investigated by polysomnography for OSAHS. The patients were classified according to theapneahypopnea index(AHI) . The level of RDW, triglyceride, cholesterol, high density lipoprotein, low density lipoprotein, hemoglobin, white blood cells and hematocritwere measured. The receiver operating characteristic curve was drawn to predict the moderate-severe OSAHS in coronary artery diseases patients according to RDW value. Results When 134 coronary artery diseases patients were classified into a control group and an OSAHS group according to the AHI, the level of RDW in two groups was not significantly different [ ( 13.44 ±1.30) % vs. ( 13.12 ±0.92) % , P gt; 0.05] . When 134 coronary artery diseases patients were classified into a control and mild OSAHS group and a moderate-severe OSAHS group according to the AHI, the level of RDW in two groups was significantly different [ ( 13.07 ±0.94) vs. ( 14.02 ±1.41) % , P lt; 0.05] . And no difference was found in hemoglobin, triglyceride, cholesterol, high density lipoprotein, low density lipoprotein, platelet, and hematocrit between two groups. The ROC curve analysis revealed that the area under ROC curve was 0.748 ( 0.523-0.972) , and the best cut-off for moderate-severe OSAHS was 13.95% with sensitivity of 71.43% and specificity of 82.98% . Conclusion RDW may be a useful and simple tool to predict moderate-severe OSAHS in coronary artery diseases patients.
【摘要】 目的 探討中型和重型顱腦損傷后患者血小板（platelet，Plt）參數的變化特點及臨床意義。 方法 選取2009年3月-2010年3月腦外傷后24 h內入院的顱腦損傷患者75例作為觀察組，于傷后1、3、7、14 d采血測定Plt數量、血小板平均體積（mean platelet volume，MPV）、血小板體積分布寬度（platelet distribution width，PDW），并同時進行格拉斯哥昏迷評分（Glasgow coma scale，GCS）。同時選取60例健康體檢者，測定Plt、MPV和PDW作為對照組。 結果 觀察組傷后1、3、7 d Plt計數分別為（106.21±36.31）、（102.76±35.23）、（108.37±31.32）×109/L，較對照組[（210.41±68.56）×109/L]明顯降低（Plt;0.05）；觀察組傷后1、3、7 d MPV分別為（12.34±1.34）、（11.21±1.52）、（10.78±1.36） fL，PDW分別為（15.78±1.26）、（17.67±1.16）、（16.72±1.21） fL，均較對照組[MPV：（8.24±1.76） fL，PDW：（12.86±1.42） fL]明顯升高（Plt;0.05）；傷后14 d Plt、MPV和PDW均較對照組差異無統計學意義（Pgt;0.05）。GCS≤8分組傷后1 d Plt計數為（96.85±36.52）×109/L，明顯低于GCSgt;8分組[（123.85±35.78）×109/L]，而GCS≤8分組MPV為（12.14±1.32） fL，PDW為（18.63±1.21） fL，均明顯高于GCSgt;8分組[MPV：（9.78±1.34） fL，PDW：（16.72±1.34） fL]，差異均有統計學意義（Plt;0.05）。傷后第1天Plt與隨訪6個月GOS評分呈正相關（r=0.625，Plt;0.05）。 結論 中型和重型顱腦損傷后Plt計數明顯降低，MPV和PDW值明顯升高，且與傷情及預后有關。Plt及其參數的檢測有助于對傷情、預后的判斷。【Abstract】 Objective To investigate the platelet parameters changes and its clinical significance in medium and severe head injury patients. Methods From March 2009 to March 2010, 75 brain injury patients hospitalized within 24 h after injury were included in this study. The platelet number (Plt), mean platelet volume (MPV), platelet volume distribution width (PDW) and Glasgow coma scale were measured on the first, third, seventh and fourteenth day after injury respectively. We also measured the Plt, MPV and PDW of 60 healthy volunteers to make comparisons. Results The Plt counts were (106.21±36.31), (102.76±35.23), and (108.37±31.32)×109/L in the head injury patients on the first, third, and 7th day respectively, which were significantly lower than those in the control group [(210.41±68.56)×109/L] (Plt;0.05); the MPV and PDW values measured on the first day [MPV: (12.34±1.34) fL, PDW: (15.78±1.26) fL] and the third day [MPV: (11.21±1.52) fL, PDW: (17.67±1.16)fL] were both significantly lower than those of the control group (Plt;0.05); There was no evidence of a difference in Plt, MPV and PDW between the two groups fourteen day after injury (P＞0.05); The Plt count was (96.85±36.52)×109/L in GCS≤8 group on the first day, which was significantly lower than that of GCSgt;8 group [(123.85±35.78) fL, Plt;0.05]; However, the MPV and PDW values in GCS≤8 group [(MPV: (12.14±1.32) fL, PDW: (18.63±1.21) fL] were both significantly higher than those of GCSgt;8 group [MPV: (9.78±1.34) fL, PDW: (16.72±1.34) fL, Plt;0.05]; The Plt count was correlated with GOS score positively (r=0.625,Plt;0.05). Conclusions Medium and severe head injury patients are significantly associated with a lower Plt count and increased MPV and PDW values. The Plt parameters changes are correlated with the prognosis of patients. Therefore, the measurement of Plt parameters may contribute to the valuation of severity and prognosis, and provide new ideas for treatment of head injury patients.
ObjectiveTo exclusively compare the short-and long-term outcomes of hepatic resection (HR) patients with multifocal tumors meeting the Milan criteria between locating in same and different sections. MethodsA total of 219 consecutive HR patients with multifocal tumors meeting the Milan criteria were divided into group SS (n=97, same section) and group DS (n=122, different sections) according to their anatomical location (Couinaud's segmentation). ResultsThe 1-, 3-, and 5-year overall survival (OS) and recurrence-free survival (RFS) rates were significantly higher in the group SS than those in the group DS (P < 0.05). The subgroup analysis showed that patients with 2 tumors and those undergoing en bloc resection were associated with better OS and RFS (P < 0.05). ConclusionsFor HCC patients with multifocal tumors meeting the Milan criteria, those with tumors locating in same hepatic section may have better longterm survival and lower HCC recurrence rates than those locating in different sections after HR.
Acute cerebral infarction is characterized by high incidence rate, high recurrence rate, high disability rate and multiple complications. Early evaluation and treatment of acute cerebral infarction is particularly important to improve the survival rate and prognosis of patients. As an easily available clinical laboratory indicator, blood routine test can reflect the pathological changes in the body to a certain extent. In recent years, many studies have shown that the indicators such as red cell volume distribution width, mean platelet volume, neutrophil to lymphocyte ratio and platelet to lymphocyte ratio in blood routine examination have important values in the onset, severity and prognosis of acute cerebral infarction. This article reviews the correlations of the above parameters and ratio parameters with acute cerebral infarction, in order to provide some reference and basis for clinical diagnosis, treatment and prognosis evaluation of acute cerebral infarction.
ObjectiveTo investigate the prognostic value of platelet volume indices ［mean platelet volume (MPV) and platelet distribution width (PDW)］ in early period for patients with sepsis .MethodsThis retrospective study was conducted in a general ICU at a University Hospital from January 2015 to January 2017. Patients with sepsis were divided into a survival group and a death group according to 28-day prognosis. The demographic and clinical data were recorded and analyzed, including platelet indices, Charlson comorbidity index, Glasgow Coma Scale (GCS) score and Acute Physiology and Chronic Health Evaluation Ⅱ (APACHEⅡ) score. Multivariable COX proportional hazard ratio model was used to evaluate the 28-day mortality risk, and receiver operating characteristic (ROC) curve were used to evaluate the value of platelet volume indices.ResultsA total of 209 patients were enrolled in this study. Mean arterial pressure, pH, platelet count, serum creatinine, bilirubin, troponin I, prothrombin time, GCS score and platelet volume indices showed significant differences between the survival group (n=137) and the death group (n=72) (all P<0.05). Multivariable COX regression analysis revealed that the PDW was independently associated with 28-day mortality in sepsis (HR=1.068, 95%CI 1.002-1.139, P=0.043). The area under the ROC curve of PDW was 0.762 (95%CI 0.694 - 0.831), with a sensitivity of 86% and a specificity of 63% at a cut-off value of 18.65%.ConclusionPDW can be used as a powerful prognostic indicator in patients with sepsis following 28-day.
【摘要】 目的 研究急性主動脈夾層時間分布規律。 方法 回顧性研究我院2000年1月-2010年12月所有急性主動脈夾層患者的時間資料，分析其月份、季節、周以及時刻分布特點。 結果 急性主動脈夾層月份分布高峰點為1月4日，高峰段為9月21日～次年4月19日（Plt;0.05）；季節分布以冬春季較多（Plt;0.05）；周分布無高峰點及高峰段（Pgt;0.05）；時刻分布高峰點為上午10點及下午4點。 結論 急性主動脈夾層具有明顯的時間分布規律，我們應該在該病的高峰時間更加重視其發生的可能，從而減少誤診，改善預后。【Abstract】 Objective To investigate the features of time distribution in the occurrence of acute aortic dissection (AAD). Methods We retrospectively analyzed all the databases of AAD in our hospital between January 1, 2000 and December 31, 2010, and studied the monthly, seasonal, weekly, and circadian distribution of the cases. Results In terms of monthly distribution, the occurrence of AAD peaked at January 4th with the high frequency in the period of September 21st to April 19th of the next year (Plt;0.05). According to the seasonal distribution, the occurrence of AAD peaked in winter and spring (Plt;0.05). There was no peak time in weekly distribution (Pgt;0.05). In accordance with circadian distribution, the occurrence of AAD peaked at 10 and 16 o’clock (Plt;0.05). Conclusion Because of the obvious rhythm of time distribution of AAD, We can pay more attention to the diagnosis of AAD especially in the peak time, thus reducing the mistakes in diagnosis and improving the prognosis.
Objective To monitor the distribution of blood perfusion during aortic arch aneurysm surgery under double arterial lines with single pump. Methods We retrospectively analyzed the clinical data of 37 patients underwent aortic arch repair or reconstruction between September 2012 and April 2014. There were 9 females and 28 males at mean age of 48.1±10.8 years ranging from 19.0-72.0 years.We took double arterial lines with single pump for cardiopulmonary bypass (CPB) during the operation and we monitored the perfusion tube flow of both the upper and lower body by blood flow detector. Cerebral blood perfusion was measured by transcranial cerebral Doppler and near-infrared spectroscopy cerebral oxygen saturation (rSO2). Results The mean CPB time of all 37 patients was 195.8±40.5 minutes ranging from 136.0-277.0 minutes and the mean duration time of selective antegrade cerebral perfusion (SCAP) was 21.6±5.6 minutes ranging from 5.0-35.0 minutes. During cooling and rewarming phases, the part of blood flow through axillary artery cannulation ranged from 31.5% to 40.8% of the whole body perfusion. The blood flow of SACP was increased to 15.0 ml / (kg·min) in 2 patients with significantly lower rSO2 and middle cerebral artery blood flow during SACP, and they had an uneventful recovery process after surgery. There were another 2 patients recorded abnormal situation of rSO2 without interventions. One patient died and the other one recovered with compications of spinal cord. Conclusions The technique of double arterial lines with single pump is reasonable and effective. The cerebral perfusion monitoring is helpful to detect abnormal perfusion during aortic arch aneurysm surgery.