descrever a tcnica operatria da drenagem pulmonar atravs do estudo anatmico 
 em cadveres , determinar se o local definido para a drenagem pulmonar  adequado e 
 seguro , e determinar a relao anatmica do tubo de drenagem com a parede 
 torcica , pulmes , grandes vasos e mediastino . foram dissecados 30 cadveres de ambos os sexos , fornecidos pelo necrotrio do 
 hospital central da santa casa de so paulo , em so paulo ( sp ) no perodo entre 
 maio e novembro de 2011 . foi inserido um dreno de ao de 7,5 cm com 24 f de 
 dimetro no segundo espao intercostal , na linha mdio - clavicular , bilateralmente , 
 e foi medida a distncia do dreno com as seguintes estruturas : brnquios 
 principais , brnquios dos lobos superiores , vasos subclvios , artrias pulmonares , 
 artrias pulmonares do lobo superior , veia pulmonar superior , veia zigos e aorta . foram realizadas medies de peso , altura , dimetro laterolateral do trax , 
 dimetro posteroanterior do trax e espessura da parede torcica de cada cadver . dos 30 cadveres dissecados , 20 e 10 eram do sexo masculino e feminino , 
 respectivamente . a mdia da extremidade distal do dreno com os brnquios 
 principais direito e esquerdo foi de 7,2 cm . a utilizao de um dreno torcico de tamanho fixo na posio preconizada  
 factvel e segura , independentemente das caractersticas antropomtricas do 
 paciente . the disease copd is a nosological entity characterized by chronic airflow obstruction , 
 associated with chronic bronchitis and emphysema . 


  in the latter , there is 
 an abnormal enlargement of the air spaces distal to the terminal bronchiole , accompanied 
 by destructive changes of the alveolar walls . in pulmonary emphysema , the destruction of the alveolar walls adversely affects the 
 essential functions of the ventilatory mechanism . without the alveolar tissue elastic 
 recoil and radial support properties , alveolar pressures will cause airway collapse 
 during exhalation . airflow communication among adjoining alveoli ( collateral 
 ventilation ) is much more prevalent in the emphysematous lung than in the normal 
 lung . bullous emphysema occurs as a result of bronchospastic obstructive disorders of the 
 bronchioles , with rupture of the interalveolar septa , forming extremely thin - walled , 
 air - filled vesicles that are functionally inert and take up considerable space in the 
 chest cavity . lung volume reduction surgery ( lvrs ) or " pneumoplasty " is indicated only in cases of 
 heterogeneous emphysema in which most of the diseased area of the lung is resected , 
 allowing the remaining tissue to work more efficiently . lung transplantation ( ltx ) is 
 the only option for patients with advanced diffuse ( homogeneous ) 
 emphysema . 


  two important limitations of ltx are the chronic shortage of organs and the limited 
 number of specialized centers , which result in increased waiting time for an organ of 
 such a magnitude that 25% of candidates for ltx die while on the waiting 
 list . both methods require general anesthesia , icu admission , and prolonged hospital stays , as 
 well as having high morbidity and mortality . , lvrs has an approximate cost of us$20,000 , whereas unilateral ltx costs 
 approximately us$400,000 . 


  in the department of surgery of the faculdade de cincias mdicas da santa casa 
 de so paulo ( fcmscsp , santa casa de so paulo school of 
 medical sciences ) , located in the city of so paulo , brazil , surgery for pulmonary 
 emphysema has been performed since 1956 , 


  such as in cases of thoracotomy 
 for resection of emphysematous pulmonary bullae . since the 1990s , video - assisted thoracic surgery has been used to treat patients with 
 bullous emphysema . however , regardless of the route of access , patients undergo general 
 anesthesia , resection of diseased lung parenchyma , and ( manual or staple ) suturing of 
 lung parenchyma . mortality ranges from 1.5% to 26% . 




  to simplify surgical treatment and reduce the number of resulting complications , 
 goldstraw et al . , 


  in 1988 , described the technique for drainage of 
 emphysematous bullae in 20 patients , with resection of costal segment and general 
 anesthesia . there was symptomatic improvement in 94% of patients , as well as objective 
 improvement in pulmonary reserve , as measured by spirometry . 


  in 1996 , a treatment alternative for patients with giant emphysematous bullae was 
 introduced by the fcmscsp surgical team : simple drainage under local 
 anesthesia . this technique was developed at our facility and is based 
 on a modification of the procedure described by monaldi 


  for the treatment 
 of tuberculous lung cavities . it is performed through a small thoracostomy in 
 association with pleurodesis with talc , which is introduced through the chest 
 tube . 


  in an article published in 2007 , botter et al . 


  described 31 procedures of 
 thoracostomy drainage of bullae under local anesthesia in 27 patients . from a functional 
 standpoint , spirometric parameters were improved one month after surgery when compared 
 with preoperative values . to provide one more treatment alternative for the relief of the debilitating effects of 
 advanced emphysema , surgeons at our institution presented , in 2008 , a new 
 protocol 


  for the treatment of patients with either homogeneous or 
 heterogeneous pulmonary emphysema who , even after having undergone the gold standard 
 treatment , continue to have disabling dyspnea . the proposed method is designed to create alternative exhalation passageways by draining 
 the lung parenchyma , thereby establishing communication between the alveoli and the 
 external environment . a small thoracotomy is performed in the second intercostal space 
 at the midclavicular line to access the affected lung . a fixed - size chest tube is placed 
 in the opening and is attached to the lung . the tube is located within the lung 
 parenchyma and is inserted after blunt dissection of the lung parenchyma . another chest 
 tube is placed into the pleural space to aid lung reexpansion , whereas the first one 
 remains in the lung indefinitely . this procedure is a surgical alternative to lvrs and ltx and has the following 
 advantages :  
 it is performed under local anesthesia , without the need for ventilatory 
 support during surgeryno resection or suturing of diseased lung parenchyma is performedimmunosuppressants are not used , and , consequently , their inconvenient adverse 
 effects are avoidedit is technically simpleit requires short hospitalization , and icu admission might not be necessaryit is inexpensive ( approximately us$1,000 ) 
  it is performed under local anesthesia , without the need for ventilatory 
 support during surgery no resection or suturing of diseased lung parenchyma is performed immunosuppressants are not used , and , consequently , their inconvenient adverse 
 effects are avoided it is technically simple it requires short hospitalization , and icu admission might not be necessary it is inexpensive ( approximately us$1,000 ) in our original study , 


  the inclusion criteria were as follows : having 
 emphysema ; being 75 years or younger ; being disabled despite having undergone the gold 
 standard treatment ( pulmonary rehabilitation ) ; having chest x - ray findings of lung 
 hyperinflation and hrct findings of homogeneous or heterogeneous emphysema ; having a 
 post - bronchodilator fev1 less than 35 - 30% of predicted , a tlc greater than 
 250% of predicted , and a dlco less than 50% of predicted ; having stopped smoking at 
 least three months before the procedure ; and being on a waiting list for ltx or 
 lvrs . after approval by the fcmscsp human research ethics committee , the first surgical 
 procedures were performed , with encouraging results . to date , 9 patients have been 
 operated on with this technique . the results for 3 of those 9 cases have been reported 
 recently . 


  despite the significant clinical improvement observed in the operated patients , there 
 have been no experimental studies describing the technical and anatomical aspects of 
 pulmonary drainage in terms of the safety of the technique in accessing the lung 
 satisfactorily without injuring the patient 's vital structures . nor have there been 
 studies designed to determine whether the use of a fixed - size chest tube , regardless of 
 the anthropometric characteristics of the patients , affects the results . we therefore designed this cadaver - based study to describe the surgical technique for 
 pulmonary drainage , to determine whether the site for the insertion of the chest tube is 
 appropriate and safe , and to determine the anatomical relationship of the chest tube 
 with the following structures : chest wall ; lungs ; large blood vessels ; and 
 mediastinum . initially , the research project was presented to the scientific committee of the 
 department of surgery and to the heads of the department of anatomic pathology of the 
 fcmscsp with the aim of obtaining authorization for its performance . after authorization was granted , the research project was submitted to the fcmscsp human research ethics 
 committee for approval . between may and november of 2011 , 30 cadavers of both genders 
 were dissected at the santa casa de so paulo central hospital 
 mortuary , located in the city of so paulo , brazil . for inclusion of cadavers in the study , family members ( or legal guardians ) gave written 
 informed consent . the consent form was presented to the family members ( or legal 
 guardians ) by one of the researchers , who answered any questions about the procedure 
 that would be performed . we included cadavers of patients at the santa casa de so paulo who 
 died of natural ( non - violent ) causes and in whom the chest wall , mediastinum , pleural 
 space , and lungs were intact . we excluded cadavers with extensive lung destruction , such as significant adhesions 
 ( cases of severe tuberculosis or pneumonia , for instance ) . the following anthropometric variables were measured on each cadaver : weight ; height ; 
 posteroanterior diameter of the chest ; laterolateral diameter of the chest ; and chest 
 wall thickness . the same pair of 7.5-cm , 24 f steel chest tubes was always used . initially , the chest tube was inserted into the second intercostal space at the 
 midclavicular line , bilaterally , perpendicularly to the chest wall . the sternum was 
 opened transversely , and the entire anterior chest wall was removed ( sternal plastron ) , 
 approximately at the level of the fourth intercostal space ( figure 1 ) . subsequently , chest wall thickness was measured 
 bilaterally , near the opening for the insertion of the chest tube . since the pleural 
 cavity was exposed , the lung was atelectatic , and the distal end of the chest tube was 
 found to be inserted into the pleural cavity ( figure 
 2 ) . with the lung in its normal anatomical position and having the 
 intrathoracic , distal end of the chest tube as a reference , we measured , with a ruler , 
 the distances from the tube to the following structures : right and left main bronchi ; 
 right and left upper lobe bronchi ; right and left upper lobe pulmonary arteries ; right 
 and left pulmonary arteries ; and right and left subclavian veins and arteries ( figure 3 ) . the lung was then pushed aside , and we 
 measured , on the left , the distance from the tube to the aortic arch and , on the right , 
 the distance from the tube to the azygos vein . figure 3distance from the distal end of the chest tube to the right upper lobe 
 artery . the variables chosen for the statistical analysis included the following : gender ; weight 
 ( kg ) ; height ( cm ) ; posteroanterior diameter of the chest ( cm ) ; laterolateral diameter of 
 the chest ( cm ) ; distance from the tube to the main bronchi ( cm ) ; distance from the tube 
 to the right and left upper lobe bronchi ( cm ) ; distance from the tube to the right and 
 left subclavian vessels ( cm ) ; distance from the tube to the right and left pulmonary 
 arteries ( cm ) ; distance from the tube to the right and left upper pulmonary arteries 
 ( cm ) ; distance from the tube to the right and left superior pulmonary veins ( cm ) ; 
 distance from the tube to the azygos vein ( cm ) ; wall thickness ( cm ) ; and distance from 
 the tube to the aorta ( cm ) . for these variables , we performed an exploratory analysis to obtain information relevant 
 to the study . for qualitative variables , we calculated frequencies and percentages , 
 whereas , for quantitative variables , we calculated means , medians , standard deviations , 
 and ranges ( minimum and maximum ) . the relationship between the 
 measured distances from the chest tube to the anatomical structures and the 
 anthropometric variables measured on the cadavers was investigated by calculation of 
 spearman 's correlation coefficient . of the 30 cadavers dissected , 20 and 10 were male and female , respectively . table 1 shows that the mean weight of the 
 operated cadavers was 68.6  2.1 kg , and the median weight was 66.5 kg . the mean height 
 was 1.70  0.02 m , and the median height was 1.70 m. the mean posteroanterior diameter 
 of the chest was 29.4  2.8 cm , and the median posteroanterior diameter was 22.5 cm . the 
 mean laterolateral diameter of the chest was 34.5  1.1 cm , and the median laterolateral 
 diameter was 34.0 cm . table 1summary of measurements of anthropometric variables.variablenminimummaximummeanmedianstandard errorweight , kg3050.088.068.666.52.1height , m301.41.91.71.70.02age , years3024.082.061.868.02.8anteroposterior diameter of the chest , cm3015.060.029.422.52.5laterolateral diameter of the chest , cm3022.053.034.534.01.1 
  we measured the distances ( in cm ) from the intrathoracic , distal end of the chest tube 
 to each of all anatomical structures in question , except wall thickness ( table 2 ) . no anatomical structure was perforated by 
 the chest tube , i.e. , none of the distances measured were equal to zero . the greatest mean distance to the chest tube was 7.2  0.2 
 cm , for the left main bronchus , and the smallest mean distance was 5.2  0.2 cm , for the 
 left upper lobe pulmonary artery . variablenminimalmaximalmeanmedianstandard errorright side 
 main bronchus304.59.07.27.00.2 
 upper lobe bronchus304.010.06.06.00.2 
 subclavian vessels304.09.06.46.50.2 
 phrenic nerve304.08.05.96.00.2 
 pulmonary artery305.010.07.16.80.2 
 upper lobe pulmonary artery304.08.55.85.80.2 
 superior pulmonary vein304.010.06.46.00.2 
 azygos vein304.011.07.07.00.3 
 wall thickness301.55.02.93.00.2left side 
 main bronchus306.010.07.27.00.2 
 upper lobe bronchus304.511.05.86.00.2 
 subclavian vessels304.09.056.06.00.2 
 phrenic nerve304.09.06.16.00.2 
 pulmonary artery304.59.06.46.20.2 
 upper lobe pulmonary artery303.59.05.25.00.2 
 superior pulmonary vein304.09.06.06.00.2 
 wall thickness301.55.02.93.00.1 
 aorta303.09.06.26.20.4aall distances are expressed in cm 
  all distances are expressed in cm in all cases , the intrathoracic , distal end of the chest tube touched or partially 
 perforated the anterior segment of the upper lobes bilaterally . the intensity of contact 
 between the chest tube and the lung depended on whether the lung was partially expanded 
 or collapsed . to our knowledge , there have been no studies describing pulmonary drainage in the 
 treatment of severe pulmonary emphysema , except for the previously mentioned studies 
 carried out by the fcmscsp team of thoracic surgeons . however , in his 
 study of collateral ventilation , macklem , in 1978 , 


  hypothetically 
 mentions creation of communication between the emphysematous parenchyma and the 
 environment as a way of decompressing trapped air . on the basis of previously demonstrated success and experience in accessing the lung 
 parenchyma , either by bronchostomy , as described by saad jr . , 


  or by 
 drainage of giant emphysematous bullae , as described by botter , 


  a clinical 
 protocol was developed for the purpose of identifying candidates for pulmonary 
 drainage . the analysis of the data gathered in this study led to some important considerations :  
 the increased posteroanterior diameter of the chest in patients with copd makes 
 the technique for pulmonary drainage recommended in the protocol even safer , 
 given that the mediastinal structures are more detached from the chest wall 
 because of the hyperinflated lungthe distal end of the chest tube was related to the anterior segments of the 
 upper lobes bilaterally ; therefore , insertion of the chest tube into the second 
 intercostal space at the midclavicular line provides satisfactory access to the 
 lung region to be drained ( target area)of the nine operated patients , eight underwent pulmonary drainage unilaterally 
 and one ( the last one ) underwent the procedure bilaterally , which was found to 
 be perfectly feasible and clinically safethere is no difference between chest wall thickness on the right and left 
 sides , the mean chest wall thickness being 2.9 cm ; since the chest tube 
 measures 7.5 cm , there were therefore 4.6 cm of intrathoracic chest tube 
 available to penetrate the cadaver lung . during the surgical procedure , 
 approximately 5 cm of chest tube is inserted into the parenchyma . from a 
 clinical standpoint , this value seems to be safe , given that there was no 
 significant bleeding during the surgical procedure , as well as efficient , 
 allowing satisfactory drainage of the trapped air . of the nine operated 
 patients , only one had bleeding through the chest tube insertion site in the 
 late postoperative period . at the time , a chest x - ray showed that the distal 
 end of the chest tube was in close contact with the peripheral vessels of the 
 lung parenchyma but not with those of the hilum . the late onset of bleeding 
 suggests neovascularization related to local foreign - body - type inflammation . once the chest tube was removed , bleeding stopped , and the chest tube insertion 
 site healed spontaneously.in the comparison of the expanded lung of a live patient with the partially 
 expanded lung of a cadaver , the distances from the distal end of the chest tube 
 to the measured structures should be different in the two cases ; however , the 
 distances from the distal end of the chest tube to the fixed structures of the 
 mediastinum ( subclavian vessels , aorta , and azygos vein ) should be similar in 
 the live patient and in the cadaverthe extent to which the chest tube penetrates into the lung was not measured 
 ( although , in all cases , the distal end of the chest tube partially penetrated 
 into or touched the anterior segments of the upper lobes ) ; nor was the severity 
 of structural damage in the drained parenchyma assessed , because , in order to 
 do so , it would be necessary to use another study model : explantation of a 
 lung , which would be connected to a respirator in order to remain expanded , 
 followed by microscopic analysis of the lesion in the drained lungfor analysis of data correlation , all of the variables were cross - referenced in 
 order to detect a pattern . in general , it was found that a greater distance 
 from the chest tube to the main bronchi translated to a greater distance from 
 the chest tube to the other mediastinal structures . an interesting finding is 
 that there was a positive relationship between weight and the left phrenic 
 nerve , i.e. , higher weight translated to a more medial position of the chest 
 tube , i.e. , on the left , drainage occurs closer to the heart in obese 
 patients.the correlation analysis also showed that chest wall thickness does not 
 correlate with weight or height . therefore , a fixed - sized chest tube can be 
 used regardless of the anthropometric characteristics of the patients , given 
 that chest wall thickness does not correlate with these variables . the increased posteroanterior diameter of the chest in patients with copd makes 
 the technique for pulmonary drainage recommended in the protocol even safer , 
 given that the mediastinal structures are more detached from the chest wall 
 because of the hyperinflated lung the distal end of the chest tube was related to the anterior segments of the 
 upper lobes bilaterally ; therefore , insertion of the chest tube into the second 
 intercostal space at the midclavicular line provides satisfactory access to the 
 lung region to be drained ( target area ) of the nine operated patients , eight underwent pulmonary drainage unilaterally 
 and one ( the last one ) underwent the procedure bilaterally , which was found to 
 be perfectly feasible and clinically safe there is no difference between chest wall thickness on the right and left 
 sides , the mean chest wall thickness being 2.9 cm ; since the chest tube 
 measures 7.5 cm , there were therefore 4.6 cm of intrathoracic chest tube 
 available to penetrate the cadaver lung . during the surgical procedure , 
 approximately 5 cm of chest tube is inserted into the parenchyma . from a 
 clinical standpoint , this value seems to be safe , given that there was no 
 significant bleeding during the surgical procedure , as well as efficient , 
 allowing satisfactory drainage of the trapped air . of the nine operated 
 patients , only one had bleeding through the chest tube insertion site in the 
 late postoperative period . at the time , a chest x - ray showed that the distal 
 end of the chest tube was in close contact with the peripheral vessels of the 
 lung parenchyma but not with those of the hilum . the late onset of bleeding 
 suggests neovascularization related to local foreign - body - type inflammation . once the chest tube was removed , bleeding stopped , and the chest tube insertion 
 site healed spontaneously . in the comparison of the expanded lung of a live patient with the partially 
 expanded lung of a cadaver , the distances from the distal end of the chest tube 
 to the measured structures should be different in the two cases ; however , the 
 distances from the distal end of the chest tube to the fixed structures of the 
 mediastinum ( subclavian vessels , aorta , and azygos vein ) should be similar in 
 the live patient and in the cadaver the extent to which the chest tube penetrates into the lung was not measured 
 ( although , in all cases , the distal end of the chest tube partially penetrated 
 into or touched the anterior segments of the upper lobes ) ; nor was the severity 
 of structural damage in the drained parenchyma assessed , because , in order to 
 do so , it would be necessary to use another study model : explantation of a 
 lung , which would be connected to a respirator in order to remain expanded , 
 followed by microscopic analysis of the lesion in the drained lung for analysis of data correlation , all of the variables were cross - referenced in 
 order to detect a pattern . in general , it was found that a greater distance 
 from the chest tube to the main bronchi translated to a greater distance from 
 the chest tube to the other mediastinal structures . an interesting finding is 
 that there was a positive relationship between weight and the left phrenic 
 nerve , i.e. , higher weight translated to a more medial position of the chest 
 tube , i.e. , on the left , drainage occurs closer to the heart in obese 
 patients . the correlation analysis also showed that chest wall thickness does not 
 correlate with weight or height . therefore , a fixed - sized chest tube can be 
 used regardless of the anthropometric characteristics of the patients , given 
 that chest wall thickness does not correlate with these variables . the placement of a fixed - size chest tube in the position specified in the clinical 
 protocol makes pulmonary drainage feasible and safe , regardless of the anthropometric 
 characteristics of the patients , given that the chest tube in this position caused no 
 injury to the structures studied .