Hao-Chien Wang

Impaired Lung Function Is Associated with Obesity and Metabolic Syndrome in Adults

Objective: Impaired lung function is associated with obesity and insulin resistance. In this study, we investigated the relationship between metabolic syndrome and impaired lung function in adults.

Polymorphism of the angiotensin-converting enzyme gene affects the outcome of acute respiratory distress syndrome.

Objective:There has been increasing evidence that angiotensin II may play an important role in the pathogenesis and in the evolution of acute lung injury. It was therefore hypothesized that polymorphisms of the angiotensin-converting enzyme gene affects the risk and outcome of acute respiratory distress syndrome (ARDS). Design:Prospective, observational study. Patients and Settings:The ARDS group consisted of 101 patients treated at the medical intensive care unit; the control groups consisted of 138 “at-risk” patients treated at the medical intensive care unit due to acute respiratory failure but did not meet the ARDS criteria throughout the hospital course, and 210 non–at-risk subjects. Intervention:None. Measurements and Main Results:The ARDS patients and control subjects were genotyped for the insertion/deletion (I/D) polymorphism of the angiotensin-converting enzyme gene. Association of the polymorphism and the risk and the outcome of ARDS was analyzed. There was no significant difference in the frequencies of the genotypes between the ARDS, at-risk, and non–at-risk groups. The 28-day mortality rates were significantly different between the three angiotensin-converting enzyme genotypes (42%, 65%, and 75% for II, ID, and DD, respectively; p = .036). Survival analysis showed that the II genotype favorably affected 28-day survival (hazard ratio, 0.46; 95% confidence interval, 0.26–0.81; p = .007), whereas ARDS caused by hospital-acquired pneumonia had a negative effect (hazard ratio, 2.34; 95% confidence interval, 1.25–4.40; p = .008). The II genotype (hazard ratio, 0.53; 95% confidence interval, 0.32–0.87; p = .012) and ARDS caused by hospital-acquired pneumonia (hazard ratio, 2.13; 95% confidence interval, 1.24–3.68; p = .006) were also significant prognostic factors for the in-hospital mortality. Conclusions:The angiotensin-converting enzyme I/D polymorphism is a significant prognostic factor for the outcome of ARDS. Patients with the II genotype have a significantly better chance of survival. This study did not show an increased risk for ARDS in Chinese patients with the D allele.

Laryngeal ultrasound: a useful method in predicting post-extubation stridor. A pilot study

The cuff-leak test was widely used for the prediction of post-extubation stridor, but controversial results limit its clinical application. The current study used real-time ultrasonography to evaluate the air-leak and hypothesised that the air-column width, measured by ultrasonography, may be correlated to the development of post-extubation stridor. From June 1, 2001 to March 1, 2002, a total of 51 planned extubations in 51 consecutively intubated patients were included. All of the patients received ultrasonographical examinations of their vocal cords and larynx in addition to an air-column width measurement within 24 h prior to extubation. The overall post-extubation stridor rate was 7.8%. The air-leak volume presented as median (interquartile range) were 300 (350) mL and 25 (20) mL, respectively, for the nonstridor and stridor groups. The air-column width during cuff deflation was 6.4 (2) mm and 4.5 (0.8) mm, respectively. They were found to be statistically significant. In conclusion, the authors demonstrated that laryngeal ultrasonography could be a reliable, noninvasive method, in the evaluation of vocal cords, laryngeal morphology and the ease of airflow, which passed through vocal cords or subglottic area due to laryngeal oedema. The air-column width during cuff deflation was a potential predictor of post-extubation stridor.

Sonographic septation: a useful prognostic indicator of acute thoracic empyema.

The aim of this study was to identify sonographic predictors of patient outcomes or need for surgical intervention of acute thoracic empyema. All patients with a clinical diagnosis of thoracic empyema underwent transthoracic ultrasonographic examination and thoracentesis at admission. According to the presence or absence of septa in sonographic images, the patients were classified into two groups: septated and nonseptated. Sonographic findings were analyzed with respect to duration of hospital stay, chest tube drainage, and treatment efficacy. A total of 163 consecutive patients were included in the study (83 patients with septated and 80 with nonseptated sonographic images). The mean duration of hospital stay (35.4 versus 27.0 days, P = 0.009) and chest tube drainage (13.1 versus 7.6 days, P < 0.001) for the patients with septa were significantly longer than for those without septa. The patients with septa were more likely to undergo intrapleural fibrinolytic therapy (63.8% versus 38.8%, odds ratio 2.79, P = 0.001) and surgical intervention (24.3% versus 7.5%, odds ratio 3.92, P = 0.004). We concluded that sonographic septation is a useful sign to predict the need for subsequent intrapleural fibrinolytic therapy and surgical intervention in cases of acute thoracic empyema. Early fibrinolytic therapy or even surgical intervention may be indicated in patients with sonographic septations.

Outcome and prognostic factors for patients with non-small-cell lung cancer and severe radiation pneumonitis

PURPOSE Radiation pneumonitis is a serious complication that develops after thoracic irradiation. The purpose of this study was to identify prognostic factors for severe radiation pneumonitis in patients with non-small-cell lung cancer. METHODS AND MATERIALS The medical records of patients with non-small-cell lung cancer and severe radiation pneumonitis were reviewed. Variables were analyzed by univariate and stepwise multivariate analysis using the Cox regression model. RESULTS Among the 31 patients, the mortality rate approached 50% in the first 2 months after the onset of radiation pneumonitis. The variables significantly associated with survival in the univariate analysis were tumor histologic feature, grade and extent (out-of-field or in-field) of radiation pneumonitis, oxygenation index, and serum albumin (<35 g/L or >or=35 g/L), and uric acid levels at the onset of radiation pneumonitis. Only the extent of radiation pneumonitis and serum albumin level were independently associated with survival in the multivariate analysis. CONCLUSION The mortality rate of non-small-cell lung cancer patients with severe radiation pneumonitis is extremely high, and survival is much shorter in patients with out-of-field radiation pneumonitis or a low serum albumin level at the onset. Additional studies to investigate the factors precipitating out-of-field radiation pneumonitis should improve the management of irradiation complications.

A pseudoepidemic of Mycobacterium chelonae infection caused by contamination of a fibreoptic bronchoscope suction channel

An unusual increase in the frequency of isolation of Mycobacterium chelonae subspecies chelonae from specimens of bronchial washings was found between September and December 1992 in National Taiwan University Hospital. During this period, a total of 123 patients underwent fibreoptic bronchoscopy with an Olympus P20. Seventy six patients had bronchial washing for bacteriological study and cytological examination. Acid-fast bacilli were found in 21 patients, in 18 of whom Mycobacterium chelonae were isolated from bronchial washing cultures. Eight patients were treated as mycobacterial infected, because of the presence of unexplained pulmonary lesion, positive acid-fast stain and culture for Mycobacterium chelonae. Diagnosis of lung cancer was delayed in one patient because of the initial negative cytological study and positive bacterial culture. The fibreoptic bronchoscope was disinfected by automated washing machine (EW-20, Olympus) using 2.3% glutaraldehyde according to a standard protocol. From a survey to search for possible sources of contamination, they were identified at the suction channel of four different bronchoscopes. This episode proved to be a pseudoepidemic. The contamination was controlled by extensive suction and rinsing of the channel with 70% alcohol immediately after disinfection by the automated bronchoscope disinfection machine. This study shows that, despite using the disinfection machine, the suction channel could still be contaminated with Mycobacterium chelonae. This may cause diagnostic confusion and unnecessary antimycobacterial treatment.

CNS infections caused by Mycobacterium abscessus complex: clinical features and antimicrobial susceptibilities of isolates

OBJECTIVES CNS infections caused by non-tuberculous mycobacteria (NTM) are rare and only three cases of CNS infections due to Mycobacterium abscessus complex have been reported. METHODS We searched the Mycobacteriology Database of the National Taiwan University Hospital and identified patients with CNS infections due to NTM. RESULTS A total of 15 patients, namely 4 HIV-seropositive patients and 11 HIV-seronegative patients, with CNS infections caused by NTM were identified during 2000-10. All of the HIV-seropositive patients had disseminated Mycobacterium avium complex infections. Among the 11 HIV-seronegative patients, NTM CNS infections were due to M. abscessus complex in 8 patients, M. avium complex in 2 patients and Mycobacterium kansasii in 1 patient. All the six preserved M. abscessus complex isolates were confirmed to be Mycobacterium massiliense by erm(41) PCR and 23S rRNA gene sequence analysis. Among the eight patients with infections due to M. abscessus complex, three had otolaryngological diseases, four had received neurosurgery and one had disseminated disease. Five patients received surgical debridement or intracranial device removal and three patients died of M. abscessus complex CNS infection. Among the five patients who survived, all received clarithromycin-based combination therapy with a median duration of 12 months and four received surgical intervention. All six isolates available for drug susceptibility testing showed uniform susceptibility to clarithromycin and five were susceptible to amikacin. CONCLUSIONS Our study revealed that M. abscessus complex isolates, particularly M. massiliense, should be considered potential pathogens causing CNS infections. Long-duration clarithromycin-based combination therapy plus surgical intervention may provide the best chance of cure.

Role of the renin-angiotensin system in ventilator- induced lung injury: An in vivo study in a rat model

Background: Injurious mechanical ventilation can cause a pro-inflammatory reaction in the lungs. Recent evidence suggests an association of the renin-angiotensin system (RAS) with lung inflammation. A study was undertaken to investigate the pathogenic role of the RAS in ventilator-induced lung injury (VILI) and to determine whether VILI can be attenuated by angiotensin converting enzyme (ACE) inhibition. Methods: Male Sprague-Dawley rats were mechanically ventilated for 4 h with low (7 ml/kg) or high (40 ml/kg) tidal volumes; non-ventilated rats were used as controls. Lung injury and inflammation were measured by the lung injury score, protein leakage, myeloperoxidase activity, pro-inflammatory cytokine levels and nuclear factor (NF)-κB activity. Expression of the RAS components was also assessed. Some rats were pretreated with the ACE inhibitor captopril (10 mg/kg) for 3 days or received a concomitant infusion with losartan or PD123319 (type 1 or type 2 angiotensin II receptor antagonist) during mechanical ventilation to assess possible protective effects on VILI. Results: In the high-volume group (n = 6) the lung injury score, bronchoalveolar lavage fluid protein concentration, pro-inflammatory cytokines and NF-κB activities were significantly increased compared with controls (n = 6). Lung tissue angiotensin II levels and mRNA levels of angiotensinogen and type 1 and type 2 angiotensin II receptors were also significantly increased in the high-volume group. Pretreatment with captopril or concomitant infusion with losartan or PD123319 in the high-volume group attenuated the lung injury and inflammation (n = 6 for each group). Conclusions: The RAS is involved in the pathogenesis of ventilator-induced lung injury. ACE inhibitor or angiotensin receptor antagonists can attenuate VILI in this rat model.

Clinical features of pandrug-resistant Acinetobacter baumannii bacteremia at a university hospital in Taiwan.

BACKGROUND AND PURPOSE The number of infections caused by Acinetobacter baumannii has increased in recent years and the emergence of pandrug-resistant A. baumannii (PDRAB) has been observed in Taiwan. The aim of this study was to evaluate the clinical features and outcomes of patients with bacteremia due to PDRAB. METHODS From January 1999 to April 2002, 30 patients with PDRAB bacteremia were treated. We analyzed the clinical characteristics of these patients, including gender, underlying diseases, clinical manifestations, antibiotic treatment, and outcome. RESULTS Bacteremia developed an average of 33 days after hospitalization and was hospital acquired in all cases. The source of bacteremia was identified in 19 patients (63.3%) and was most commonly from the respiratory tract. The overall mortality was 60% (18 patients). Among these, the cause of death was directly related to PDRAB bacteremia in 12. Underlying heart disease, shock, resuscitation, acute respiratory distress syndrome, mechanical ventilation, and multiple organ dysfunction score (MODS) were significant predictors of mortality after the development of PDRAB bacteremia. No specific antimicrobial therapy appeared to be effective. CONCLUSIONS Clinical outcomes of patients with PDRAB bacteremia were related to the medical conditions of the patients at the time of development of bacteremia and could be predicted by the MODS. The only way to limit the spread is through strict preventive measures for nosocomial infection and antibiotic control.

Fas/Fas ligand pathway is involved in the resolution of type II pneumocyte hyperplasia after acute lung injury: evidence from a rat model.

Objective We used a rat model of acute lung injury to evaluate the role of apoptosis of type II pneumocytes in alveolar remodeling during the resolution phase. Design Controlled animal study. Setting University research laboratory. Subjects Sprague-Dawley rats. Interventions Sprague-Dawley rats had Escherichia coli lipopolysaccharide instilled transtracheally to induce acute lung injury. Animals were killed on various days after lipopolysaccharide instillation. Lung specimens from all animals were examined for the presence of apoptosis in type II pneumocytes by an in situ apoptosis assay and for proliferative nuclear antigen, cytokeratin-18, Fas, and Fas ligand with an immunohistochemical stain. Fas and Fas ligand expression in both lung tissue and bronchoalveolar lavage fluid was examined by Western blot analysis. Measurements and Main Results Histologic examination revealed that the lungs of rats with acute lung injury showed infiltration of numerous inflammatory cells in the intra-alveolar and/or interstitial space and hyperplasia of type II pneumocytes. Type II pneumocyte proliferation, detected by proliferative nuclear antigen staining, developed maximally around day 3 after acute lung injury. In the in situ apoptosis assay, positive signals in type II pneumocytes were obvious and were distributed diffusely in the lung parenchyma from day 1 after acute lung injury, became maximal around day 7, then declined until day 21. DNA fragmentation analysis revealed that a DNA ladder pattern was detectable from day 3, persisted until day 10, and disappeared after day 14. The major cell types expressing Fas ligand are macrophages and neutrophils. Western blot analysis showed that Fas ligand, both membrane-bound form and soluble form, was present from day 1 to day 21 after acute lung injury, with highest level occurring during the first week of acute lung injury. Fas expression in type II pneumocytes reached its maximum on days 3–5 and then gradually declined until day 21. Fas and Fas ligand expression appeared to proceed type II pneumocyte apoptosis. After the acute stage, Fas and Fas ligand expression declined, and type II pneumocyte apoptosis also decreased. These findings correlate with histologic resolution of type II pneumocyte hyperplasia. Conclusions Our results confirm that type II pneumocyte proliferation in response to acute lung injury is mainly a reparative phenomenon. During the resolution phase of acute lung injury, extensive apoptosis of type II pneumocytes is the main cellular mechanism that accounts for the disappearance of these cells, and Fas/Fas ligand is involved in the resolution of type II pneumocytes. Our model may provide a useful tool to assess the mechanisms of tissue remodeling after acute lung injury.