A Novel Extracorporeal CO2 Removal System: Results of a Pilot Study of Hypercapnic Respiratory Failure in Patients With COPD.

Chest. 2013 Mar 1;143(3):678-86

Authors: Burki NK, Mani RK, Herth FJ, Schmidt W, Teschler H, Bonin F, Becker H, Randerath WJ, Stieglitz S, Hagmeyer L, Priegnitz C, Pfeifer M, Blaas SH, Putensen C, Theuerkauf N, Quintel M, Moerer O

Abstract
BACKGROUND: Hypercapnic respiratory failure in patients with COPD frequently requires mechanical ventilatory support. Extracorporeal CO2 removal (ECCO2R) techniques have not been systematically evaluated in these patients.
METHODS: This is a pilot study of a novel ECCO2R device that utilizes a single venous catheter with high CO2 removal rates at low blood flows. Twenty hypercapnic patients with COPD received ECCO2R. Group 1 (n = 7) consisted of patients receiving noninvasive ventilation with a high likelihood of requiring invasive ventilation, group 2 (n = 2) consisted of patients who could not be weaned from noninvasive ventilation, and group 3 (n = 11) consisted of patients on invasive ventilation who had failed attempts to wean.
RESULTS: The device was well tolerated, with complications and rates similar to those seen with central venous catheterization. Blood flow through the system was 430.5 ± 73.7 mL/min, and ECCO2R was 82.5 ± 15.6 mL/min and did not change significantly with time. Invasive ventilation was avoided in all patients in group 1 and both patients in group 2 were weaned; PaCO2 decreased significantly (P < .003) with application of the device from 78.9 ± 16.8 mm Hg to 65.9 ± 11.5 mm Hg. In group 3, three patients were weaned, while the level of invasive ventilatory support was reduced in three patients. One patient in group 3 died due to a retroperitoneal bleed following catheterization.
CONCLUSIONS: This single-catheter, low-flow ECCO2R system provided clinically useful levels of CO2 removal in these patients with COPD. The system appears to be a potentially valuable additional modality for the treatment of hypercapnic respiratory failure.
TRIAL REGISTRY: ClinicalTrials.gov; No.: NCT00987740 and 01021605; URL: www.clinicaltrials.gov.

PMID: 23460154 [PubMed - in process]

Effect of Emphysema on CT Scan Measures of Airway Dimensions in Smokers.

Chest. 2013 Mar 1;143(3):687-93

Authors: Diaz AA, Han MK, Come CE, San José Estépar R, Ross JC, Kim V, Dransfield MT, Curran-Everett D, Schroeder JD, Lynch DA, Tschirren J, Silverman EK, Washko GR

Abstract
BACKGROUND: In CT scans of smokers with COPD, the subsegmental airway wall area percent (WA%) is greater and more strongly correlated with FEV1 % predicted than WA% obtained in the segmental airways. Because emphysema is linked to loss of airway tethering and may limit airway expansion, increases in WA% may be related to emphysema and not solely to remodeling. We aimed to first determine whether the stronger association of subsegmental vs segmental WA% with FEV1 % predicted is mitigated by emphysema and, second, to assess the relationships among emphysema, WA%, and total bronchial area (TBA).
METHODS: We analyzed CT scan segmental and subsegmental WA% (WA% = 100 × wall area/TBA) of six bronchial paths and corresponding lobar emphysema, lung function, and clinical data in 983 smokers with COPD.
RESULTS: Compared with segmental WA%, the subsegmental WA% had a greater effect on FEV1% predicted (-0.8% to -1.7% vs -1.9% to -2.6% per 1-unit increase in WA%, respectively; P < .05 for most bronchial paths). After adjusting for emphysema, the association between subsegmental WA% and FEV1 % predicted was weakened in two bronchial paths. Increases in WA% between bronchial segments correlated directly with emphysema in all bronchial paths (P < .05). In multivariate regression models, emphysema was directly related to subsegmental WA% in most bronchial paths and inversely related to subsegmental TBA in all bronchial paths.
CONCLUSION: The greater effect of subsegmental WA% on airflow obstruction is mitigated by emphysema. Part of the emphysema effect might be due to loss of airway tethering, leading to a reduction in TBA and an increase in WA%.
TRIAL REGISTRY: ClinicalTrials.gov; No.: NCT00608764; URL: www.clinicaltrials.gov.

PMID: 23460155 [PubMed - in process]

Cardiovascular Disease in COPD: Mechanisms.

Chest. 2013 Mar 1;143(3):798-807

Authors: Maclay JD, Macnee W

Abstract
It is now well established that cardiovascular disease contributes significantly to both morbidity and mortality in COPD. Shared risk factors for cardiovascular disease and COPD, such as smoking, low socioeconomic class, and a sedentary lifestyle contribute to the natural history of each of these conditions. However, it is now apparent that alternative, novel mechanisms are involved in the pathogenesis of cardiovascular disease, and these may play an important role in driving the increased cardiovascular risk associated with COPD. In this article, we discuss the potential mechanisms that link COPD to an increased risk of cardiovascular disease.

PMID: 23460157 [PubMed - in process]

Low dose CT screening for lung cancer could save 12 000 US lives a year, researchers claim.

BMJ. 2013;346:f1302

Authors: Tanne JH

PMID: 23444441 [PubMed - in process]