Chiung Zuei Chen

Prediction of Arterial Blood Gas Values from Venous Blood Gas Values in Patients with Acute Respiratory Failure Receiving Mechanical Ventilation

BACKGROUND AND PURPOSE Arterial blood gas (ABG) analysis is useful in evaluation of the clinical condition of critically ill patients; however, arterial puncture or insertion of an arterial catheter may cause many complications. This study evaluated whether pH, partial pressure of carbon dioxide (PCO2) and bicarbonate (HCO3-) values of venous blood gas (VBG) could accurately predict their ABG analogs for patients with acute respiratory failure treated by mechanical ventilation in an intensive care unit (ICU). METHODS Forty six patients who were admitted to the ICU due to acute respiratory failure and treated by mechanical ventilation were included in this study. Blood for VBG analysis was sampled from the cubital or dorsal palmar veins, while ABG was sampled simultaneously from the radial or brachial arteries via an arterial catheter at the other upper extremity. Regression equations and mean percentage-difference equations were derived to predict arterial pH, PCO2, and HCO3- values from their VBG analogs. The equations were validated by evaluating VBG and ABG samples from a separate group of 11 patients. RESULTS A total of 46 paired samples from 46 patients were evaluated. The mean percentage differences between the venous and arterial values divided by venous values for pH, PCO2, and HCO3- were (mean +/- SD): deltapH (%), 0.50 +/- 0.45; deltaPCO2 (%), 17.09 +/- 9.60; and deltaHCO3- (%), 9.72 +/- 7.73; respectively. Regression equations for prediction of pH, PCO2 and HCO3- values were: arterial pH (pHa) = 0.45 + 0.94 x venous pH (pHv) [r = 0.83, p < 0.0001]; partial pressure of arterial CO2 (PaCO2) = 3.06 + 0.76 x partial pressure of venous CO2 (PvCO2) [r = 0.86, p < 0.0001]; and arterial HCO3- (HCO3-a) = 2.34 + 0.82 x venous HCO3- (HCO3-v) [r = 0.91, p < 0.0001]. The predicted ABG values from the mean percentage-difference equations were derived as follows: pHa = pHv x 1.005; PaCO2 = PvCO2 x 0.83; and HCO3-a = HCO3-v x 0.90. Validation of the regression equations and mean percentage-difference equations revealed only a small (clinically insignificant) variation between the actual and predicted ABG values. CONCLUSIONS Venous blood gas can accurately predict the ABG values of pH, PCO2 and HCO3- for patients with acute respiratory failure being treated with mechanical ventilation.

Genetic variants of pulmonary SP‐D predict disease outcome of COPD in a Chinese population

Although surfactant protein‐D (SP‐D) has been suggested as a biomarker for chronic obstructive pulmonary disease (COPD), the relationship between genetic variants of SP‐D and disease outcome of COPD remains unknown. We hypothesized that genetic polymorphisms of SP‐D are associated with COPD‐related phenotypes and disease prognosis.

Using Post-bronchodilator FEV1 is Better Than Pre-bronchodilator FEV1 in Evaluation of COPD Severity

Abstract Background: The current standards for the diagnosis and treatment of patients with COPD clearly rely on the Global Initiative for Chronic Obstructive Lung Disease (GOLD) criteria based on post-bronchodilator spirometric values. However, clinical evidence for using the post-bronchodilator FEV1 in the severity classification has not been fully investigated. Methods: Patients with COPD were enrolled and followed up prospectively between October 2006 and January 2011. We compared the observed 3-year risk of all causes and respiratory mortality with the risk predicted by the pre- and post-bronchodilator percent predicted FEV1. Other important phenotypes including BMI, MMRC dyspnea scale, ECOG performance status and severe AECOPD (acute exacerbation) were also compared between the two groups. The different severity classifications of COPD, measured according the GOLD guidelines by post- and pre-bronchodilator percent predicted FEV1 were compared for prediction of mortality. Results: There were 35 deaths among the 300 COPD patients (11.7%). Multivariate analysis showed that the post-bronchodilator percent predicted FEV1 was a significant independent predictor of mortality but pre-bronchodilator percent predicted FEV1 was not (p = 0.008 vs 0.126) and it was more strongly correlated with all studied predictors of outcome than the pre-bronchodilator percent predicted FEV1. Kaplan-Meier analysis showed that the discrimination ability to predict mortality from the GOLD criteria using post bronchodilator percent predicted FEV1 (p = 0.009) was better than using pre-bronchodilator percent predicted FEV1 (p = 0.131). Conclusions: The post-bronchodilator percent predicted FEV1 is better than the pre-bronchodilator percent predicted FEV1 in the evaluation of the severity of disease in COPD patients and is more accurate in predicting the risk of death by the GOLD classification.

Comparison of global initiative for chronic obstructive pulmonary disease 2013 classification and body mass index, airflow obstruction, dyspnea, and exacerbations index in predicting mortality and exacerbations in elderly adults with chronic obstructive pulmonary disease.

To examine whether the Global Initiative for Chronic Obstructive Pulmonary Disease (GOLD) 2013 revision offers greater predictive ability than the body mass index, airflow obstruction, dyspnea, and exacerbations (BODEx) index in elderly adults with chronic obstructive pulmonary disease (COPD).

Repeated Pneumonia Severity Index Measurement After Admission Increases its Predictive Value for Mortality in Severe Community-acquired Pneumonia

BACKGROUND/PURPOSE Severe community-acquired pneumonia (CAP) is associated with high hospital mortality, and accurate assessment of patients is important for supporting clinical decision making. The Pneumonia Severity Index (PSI) is a good tool for predicting disease severity, especially in the low-risk group of patients with CAP. We investigated whether the change in PSI measurement after admission could identify patients at high risk of mortality from CAP. METHODS We prospectively studied 250 inpatients with CAP. PSI was measured at admission and 72 hours later at a tertiary referral medical center from May 2005 to February 2006. The initial and repeated PSI results were compared. Hospital mortality was used as the outcome measure. RESULTS Initial PSI in high-risk patients (PSI class > IV) had a low specificity (37%), and a low positive predictive value (PPV) (17%). Increased repeated PSI score, as compared with initial score, was associated with an increased mortality rate (from 7.8% to 33.3% in class IV, and 25.3% to 53.3% in class V; p < 0.0001), and improved the predictive value, with 94% specificity and a PPV of 46% for mortality in high-risk patients. CONCLUSION Increased PSI score, 72 hours after admission, for patients with CAP improved the predictive value of PSI score and more accurately identified patients with a high risk of mortality.

Small airways obstruction syndrome in clinical practice.

Background and objective:  Small airways obstruction syndrome (SAOS) is a particular pulmonary function test (PFT) pattern showing decreased VC and FEV1 but a normal FEV1/VC ratio and TLC. The significance of this syndrome in clinical practice has not been comprehensively investigated.

The Role of Bactericidal/Permeability-Increasing Protein in Men with Chronic Obstructive Pulmonary Disease

Abstract Background and objective: Bactericidal/permeability-increasing protein (BPI) is a member of the pattern recognition receptors of the innate immune system. Recently, an association between genetic polymorphism in the BPI gene and a risk of airflow decline after transplantation was demonstrated, but whether these findings are reproducible in nontransplantation populations, such as those with COPD, is still unknown. The aim of this study is to explore the role of BPI in COPD. Methods: The genotypes of 107 patients with COPD and 110 control subjects were evaluated by polymerase chain reaction and polymorphism analysis of the BPI genes and ELISA analysis of the plasma BPI level. All subjects were men over 40 years old who smoked. Results: BPI mutation PstI (T→C) polymorphism in intron 5 was associated with an increased risk of developing COPD (OR 3.73, 95%CI: 1.62–9.10), and the frequency was significantly increased in the COPD group compared with the control group (26/107 [24.3%] vs 12/110 [10.9%], p = 0.002). In addition, COPD patients exhibited a decreased plasma level of BPI compared with the control group (10.6 ± 2.2 vs 23.4 ± 2.1ng/ml, p < 0.0001). Conclusions: BPI mutation (PstI in intron 5) and a decreased plasma BPI level were significant risk factors in susceptibility to COPD. These results demonstrate that BPI genetic mutation and impaired BPI production or release may result in airflow obstruction in smokers.

Chronic and Repeated Chlamydophila pneumoniae Lung Infection can Result in Increasing IL-4 Gene Expression and Thickness of Airway Subepithelial Basement Membrane in Mice

BACKGROUND/PURPOSE Chlamydophila pneumoniae infection has been associated with several pulmonary and cardiac diseases. However, it has not been explored for its ability to activate the same immunopathologic mechanisms of asthma, namely, a predominant Th2 immune response and structural changes that are termed airway remodeling. This study evaluated immune responses in the lung and airway pathology of BALB/c mice with chronic and repeated C. pneumoniae infections. METHODS Mice were inoculated intranasally with 5 x 10(6) inclusion-forming units of C. pneumoniae TWAR strain, and re-inoculated at 14 and 42 days after the primary inoculation. Cytokine gene expression in bronchoalveolar lavage (BAL) cells was analyzed by RT-PCR on day 70. Airway pathology was also evaluated by morphometric measurements. RESULTS A significant increase of interleukin (IL)-4 mRNA was detected in BAL cells in infected mice, and a significant increase in subepithelial basement membrane thickness of the airways was also noted in infected mice as compared with control mice (8.95 +/- 0.28 microm vs. 5.54 +/- 0.22 microm, p < 0.0001). We further analyzed the correlation between IL-4 cytokine expression and the increased subepithelial basement membrane thickness of airways in infected mice. We found that mice with increased IL-4 mRNA expression had significant increases in the thickness of subepithelial basement membrane as compared with mice without increased IL-4 mRNA expression (9.87 +/- 0.51 microm vs. 6.49 +/- 0.52 microm, p < 0.0001). CONCLUSION It is believed that our results demonstrated for the first time that chronic and repeated infections with C. pneumoniae increased IL-4 gene expression and thickness of airway subepithelial basement membrane in mice.

Value of the Pneumonia Severity Index in Assessment of Community-Acquired Pneumonia

BACKGROUND AND PURPOSE The value of the Pneumonia Severity Index (PSI) in predicting the mortality of patients with community-acquired pneumonia has not been reported in Taiwan. This study investigated the value of this scoring system in estimating mortality of inpatients with community-acquired pneumonia. METHODS This was a prospective observational study of 118 inpatients and a retrospective chart review of 115 inpatients with radiographically-confirmed community-acquired pneumonia treated at a tertiary referral medical center in southern Taiwan. Patients were stratified into 5 risk classes according to PSI score. Data on demographic characteristics, comorbidities, baseline clinical and laboratory features, in-hospital mortality and length of hospital stay were analyzed. RESULTS The mortality rates according to risk classification were 0% for class I and II, 2.5% for class III, 8.2% for class IV, and 31.2% for class V. A significant correlation was found between these risk classes and medical outcome (p < 0.001). The length of hospital stay was significantly associated with risk class, and ranged from 6.3 days for class I patients to 18 days for class V (p < 0.001). CONCLUSION The PSI provided a useful prediction of medical outcome in patients with community-acquired pneumonia. To decrease unnecessary admission, further prospective studies are needed to determine whether outpatient therapy is appropriate for class I or class II patients with community-acquired pneumonia.

Discriminative and predictive properties of multidimensional prognostic indices of chronic obstructive pulmonary disease: A validation study in Taiwanese patients

Chronic obstructive pulmonary disease (COPD) is a pulmonary disease with systemic involvement. Several multidimensional indices have been developed to predict long‐term outcomes. However, these indices have not been compared and validated in Taiwanese patients with COPD.