[Downloaded free from http://www.lungindia.com on Wednesday, September 28, 2016, IP: 84.134.164.227] Letters to Editor
Financial support and sponsorship Nil. Conflicts of interest There are no conflicts of interest.
Ammaiyappan Chockalingam, Ranganathan Duraiswamy, Madhavan Jagadeesan1,2 Department of Thoracic Medicine, Rajiv Gandhi Government General Hospital, Madras Medical College, 1Dualhelix Genetic Diagnostics, 2Vasan Medical Research Trust, Chennai, Tamil Nadu, India E‑mail:
[email protected]
2.
Meyer KC, Raghu G, Baughman RP, Brown KK, Costabel U, du Bois RM, et al. An official American Thoracic Society clinical practice guideline: The clinical utility of bronchoalveolar lavage cellular analysis in interstitial lung disease. Am J Respir Crit Care Med 2012;185:1004‑14.
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Website: www.lungindia.com DOI: 10.4103/0970-2113.189004
REFERENCES 1.
Chockalingam A, Duraiswamy R, Jagadeesan M. Bronchoalveolar lavage cellular analyses in conjunction with high‑resolution computed tomography imaging as a diagnostic intervention for patients with suspected interstitial lung disease. Lung India 2016;33:287‑91.
How to cite this article: Chockalingam A, Duraiswamy R, Jagadeesan M. Response to bronchoalveolar lavage and highresolution computed tomography in interstitial lung disease. Lung India 2016;33:581-2.
High resolution computed tomography in chronic obstructive pulmonary disease patients: Do not forget radiation hazard Sir, We read with interest the original article titled “Correlation between clinical characteristics, spirometric indices and high‑resolution computed tomography (HRCT) findings in patients of chronic obstructive pulmonary disease (COPD)” by Singh et al.[1] In this study, the authors have rightly concluded that quantifying a complex and multisystem disease like COPD by spirometry alone is neither justified nor feasible in all cases. The authors further concluded that HRCT thorax may be used for holistic evaluation of COPD patients. However using HRCT in all COPD patients may not be appropriate. First, the radiation hazard associated with HRCT is a well‑established fact. COPD and smoking are known risk factors for lung cancer. Many previous studies point toward the possible radiation risk even with a low dose computed tomography scan done as a part of regular lung cancer screening program.[2] Some studies further suggest a possible synergistic interaction between the risk from smoking and radiation exposure.[3,4] Hence performing HRCT in all COPD patients will further add to the risk of lung cancer in these patients. Second, performing HRCT for all COPD patients will not be cost effective. This financial aspect becomes particularly more important in a resource‑limited setting like India where even after a diagnosis of COPD patients may not be able to afford the cost of treatment. 582
The author further concluded that HRCT can well be correlated with the spirometric and clinical features, and the level of obstruction can be indirectly derived from it by measuring the mean lung density (MLD). In this study, the authors have only recruited stable COPD subjects. However, during exacerbation of COPD, which are mostly infective, presence of new opacities like consolidation will change the MLD on HRCT. Hence, it is difficult to say that the MLD will correlate with the level of obstruction in COPD patients with exacerbation. Therefore, we suggest that an alternative technique like impulse oscillometry that correlates well with spirometry and is free of radiation hazard be used in all COPD patients who cannot perform spirometry. Studies suggest that it can assess the COPD pathology even earlier that spirometry. [5,6] Two‑dimensional echocardiography is an excellent noninvasive screening tool to rule out pulmonary hypertension, especially in COPD patients who present with symptoms that are out of proportion to their disease and may help in the holistic management of COPD patients.[7] HRCT should not be used in all COPD patients, and its role may be limited to ruling out alternative diagnoses and for presurgical assessment before lung volume reduction surgeries or bullectomy. Financial support and sponsorship Nil. Lung India • Vol 33 • Issue 5 • Sep - Oct 2016
[Downloaded free from http://www.lungindia.com on Wednesday, September 28, 2016, IP: 84.134.164.227] Letters to Editor
Conflicts of interest There are no conflicts of interest.
Swetabh Purohit, Naveen Dutt, Lokesh Saini, Ravi Panwar, Sunil Kumar Department of Pulmonary Medicine, All India Institute of Medical Sciences, Jodhpur, Rajasthan, India E‑mail:
[email protected]
REFERENCES 1.
2. 3. 4.
5.
Singh A, Kumar S, Mishra AK, Kumar M, Kant S, Verma SK, et al. Correlation between clinical characteristics, spirometric indices and high resolution computed tomography findings in patients of chronic obstructive pulmonary disease. Lung India 2016;33:42‑8. Brenner DJ. Radiation risks potentially associated with low‑dose CT screening of adult smokers for lung cancer. Radiology 2004;231:440‑5. Pierce DA, Sharp GB, Mabuchi K. Joint effects of radiation and smoking on lung cancer risk among atomic bomb survivors. Radiat Res 2003;159:511‑20. Tokarskaya ZB, Scott BR, Zhuntova GV, Okladnikova ND, Belyaeva ZD, Khokhryakov VF, et al. Interaction of radiation and smoking in lung cancer induction among workers at the Mayak nuclear enterprise. Health Phys 2002;83:833‑46. Piorunek T, Kostrzewska M, Cofta S, Batura‑Gabryel H, Andrzejczak P,
6. 7.
Bogdanski P, et al. Impulse oscillometry in the diagnosis of airway resistance in chronic obstructive pulmonary disease. Adv Exp Med Biol 2015;838:47‑52. Frantz S, Nihlén U, Dencker M, Engström G, Löfdahl CG, Wollmer P. Impulse oscillometry may be of value in detecting early manifestations of COPD. Respir Med 2012;106:1116‑23. Gupta NK, Agrawal RK, Srivastav AB, Ved ML. Echocardiographic evaluation of heart in chronic obstructive pulmonary disease patient and its co‑relation with the severity of disease. Lung India 2011;28:105‑9.
This is an open access article distributed under the terms of the Creative Commons Attribution‑NonCommercial‑ShareAlike 3.0 License, which allows others to remix, tweak, and build upon the work non‑commercially, as long as the author is credited and the new creations are licensed under the identical terms.
Access this article online Quick Response Code:
Website: www.lungindia.com DOI: 10.4103/0970-2113.189006
How to cite this article: Purohit S, Dutt N, Saini L, Panwar R, Kumar S. High resolution computed tomography in chronic obstructive pulmonary disease patients: Do not forget radiation hazard. Lung India 2016;33:582-3.
Cardiac troponin trends and severity in chronic obstructive pulmonary disease exacerbation: Are limits properly associated for Intensive Care Unit outcome? Sir, We read the report by Noorain[1] in the latest issue of Lung India with great interest. In this single‑center prospective study, he tried to highlight the prognostic significance of admission cardiac troponin I (cTnI) in chronic obstructive pulmonary disease (COPD) exacerbation. This is an important and controversial issue because cardiovascular co‑morbidities in COPD worsen the outcome of exacerbations.[2] We are agree that cTnI could be a high‑density determination factor correlated with Intensive Care Unit (ICU) admission and mechanical ventilator requirement. However, we consider that there are key some practical questions to be answered for a proper clinical extrapolation. First, regarding cTnI threshold need more consideration. In previous studies by Baillard et al.[3] and Martins et al.[4] cTnI was shown in associations with mortality and worse outcomes. However, there is not clear reason for the threshold of cTnI 0.017 μg/L (0.17 ng/ml) chosen as the cut off point for statistical analysis in Noorain’s study. Is it calculated from receiver‑operating characteristic curves or does it represent the mean value (mean value is 0.272 μg/L)?. This aspect needs more definitions for clinical implications.
Second, the association of acute COPD exacerbation and other diagnosis such as pulmonary embolism (PE) as relatively frequents cause of increased plasma troponin levels is not clear and this is a key aspect for appropriate diagnosis in this study.[1] PE is particularly difficult to diagnose in critically ill patients because tests that may be suggestive of physiological alterations compatible with PE (e.g., decreased oxygen saturation, increased plasma cTnI) are often nonspecifically abnormal in critically ill patients. Katsios et al. showed that pretest probability scores such as Geneva diagnostic PE score, Wells, modified Wells, and simplified Wells diagnostic scores developed outside the ICU do not correlate with adjudicated PE categories in critically ill patients. [5] In Noorain’s study probability of PE was evaluated by using Wells score. However, it was stated that 34 (68%) patients (94.7% in Troponin I positive group, 51.6% in Troponin I negative group) were admitted to ICU. He also stated that mean SpO2 of Troponin I positive group was 75% and 63.2% of these patients had dilated right heart chambers. In our opinion, it seems to be difficult to rule out the PE with Wells score only. It was shown that the negative predictive values the Wells score combined with D‑dimer is near to 100%.[6] There were no data
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