Air leaks remain one if not the most common complication

GENERAL THORACIC The Benefits of Continuous and Digital Air Leak Assessment After Elective Pulmonary Resection: A Prospective Study Robert J. Cerfolio, MD, and Ayesha S. Bryant, MSPH, MD Division of Cardiothoracic Surgery, University of Alabama at Birmingham, Birmingham, Alabama Background. Air leaks remain the most common pulmonary complication after elective pulmonary resection, yet their assessment, unlike other clinical bedside indicators, remains analogue and not digital. Methods. This prospective randomized study compared a digital air leak system with the current analogue days, p 0.034) and reduced hospital stay (mean, 3.3 vs 4.0 days, p 0.055). Three patients were discharged home with the device, without complications. Conclusions. The digital and continuous measurement of air leaks instead of the currently used static analogue systems reduces hospital length of stay by more accu- and reproducibly measuring air leaks. This leads air leak system in 100 patients that underwent electiverately pulmonary resection. to quicker chest tube management decisions because the Results. The digital and analogue patient groups each average size of an air leak during the last several hours had 50 patients. Pulmonary function, types of pulmonarycan be determined. Intrapleural pressure curves may also resection, number of chest tubes, and pathology were nothelp predict the optimal chest tube setting for each statistically different between the groups. The digital patient s air leak and eliminate the need for chest roent- Further studies on the pleural pressure system confirmed the air leak status in 5 patients thatgenograms. were equivocal on the analogue system. The ability tocurves and this device are needed. assess the air leak status continuously afforded quicker (Ann Thorac Surg 2008;86:396 401) chest tube removal in the digital group (mean, 3.1 vs 3.9 2008 by The Society of Thoracic Surgeons Air leaks remain one if not the most common complication after pulmonary resection [1]. Despite the development of many intraoperative techniques to help reduce them, including fissureless surgery, pleural tents, pneumoperitoneum, and the use of glues and sealants, about 20% of patients arrive at the recovery room with an air leak [2 7]. Unfortunately, anywhere from 5% to 10% still have an air leak on postoperative day 3 or 4, when most patients should be otherwise ready for discharge after a thoracotomy or video-assisted thoracoscopic lobectomy [8]. Prolonged air leaks are the most common cause of prolonged hospitalization and add significantly to the cost. Although we and others have published reports on the ability to discharge patients home with air leaks with chest tubes attached to compact drainage devices, and the outpatient management of air leaks to reduce costs, patients satisfaction is much higher when they go home without a tube in their chest [5, 8]. Thus our goal should continue to be to remove the tubes within 2 to 3 days after pulmonary resection and to allow for fast-tracking with discharge home with no chest tube. The measurement or grading of air leaks, despite the development, verification, and use of an air leak classification system, currently relies on a static analogue system that still has observer variability and subjectivity because is based on the observations of bubbles in a column [2]. Recently, several devices have been designed that are able to measure air leaks continuously and digitally. We present our experience with one of these new digital air leak devices. We are also currently involved in a different study using another digital air leak device. Patients and Methods This is a prospective study of patients who underwent elective pulmonary resection by 1 general thoracic surgeon at the University of Alabama at Birmingham. Patients younger than age 19 were excluded from the study. Before resection patients, with suspicious or biopsyproven non-small cell lung cancer underwent routine staging using computed tomography (CT) and positronemission tomography (PET) scanning, as described at length [9 12]. In addition, patients underwent risk assessment, which included assessment of their cardiac function as well as measurement of their pulmonary function consisting of percentage of forced expiratory Accepted for publication April 9, 2008. Address correspondence to Dr Cerfolio, Department of Surgery, Division of Cardiothoracic Surgery, University of Alabama at Birmingham, 703 19th St S, ZRB 739, Birmingham, AL 35294; e-mail: rcerfolio@uab.edu. Dr Cerfolio discloses that he has a financial relationship with Millicore. 2008 by The Society of Thoracic Surgeons 0003-4975/08/$34.00 Published by Elsevier Inc doi:10.1016/j.athoracsur.2008.04.016

Ann Thorac Surg CERFOLIO AND BRYANT 2008;86:396 401 AIR LEAKS: CONTINUOUS AND DIGITAL MONITORING volume in 1 second (FEV 1 %), percentage diffusion capacity of the lung for carbon monoxide (Dlco%,), Dlco adjusted, and their Dlco/alveolar volume percentage. All patients underwent posterior-lateral serratus anterior-sparing, rib-sparing, and intercostal nerve-sparing thoracotomy and appropriate types of pulmonary resection with complete thoracic lymphadenectomy [13 16]. Patients were randomized according to age, sex, and type of pulmonary resection. The randomization process was accomplished using a program that ensured the two groups were matched for these three variables: age, sex, and the type of pulmonary resection performed. Sealed envelopes contained a card on which was printed one of the two types of drainage system. The envelope was not opened until the subcutaneous tissue was being closed. After the envelope was opened, the appropriate drainage system was determined and attached to the chest tube. The University of Alabama at Birmingham s Institutional Review Board approved this study as well as the electronic prospective database used. Individual patient consent was obtained for use in this prospective database but was waived for inclusion in this particular study. Chest Tube Management Patients underwent posterior lateral thoracotomy and at the completion of the procedure were randomized to have their chest tubes placed to the Sahara S-11000 (Teleflex, Research Triangle Plus, NC), which features a 7 column-air leak meter within it, or to the Digivent (Millicore, Sweden). The Digivent system features a tearshaped controller unit that sits on top of drainage collection chamber. It has a digital air leak detection meter that reports air leaks continuously in milliliters per minute. All patients chest tubes were placed to 20 cm of wall suction on the day of operation and then placed to water seal on the morning of postoperative day 1. Patients remained on water seal throughout their hospitalization unless they experienced increasing subcutaneous emphysema on physical examination or by chest roentgenogram, or both, or if they had an increasing pneumothorax that led to a decrease in saturation. The patients in this study underwent a portable chest roentgenogram each morning. For patients randomized to the Sahara system, if an air leak was detected on morning rounds, the size and type of the leak was recorded based on the Robert David Cerfolio (RDC) classification system, which is the only verified air leak system available [2, 3, 17]. Patients then were placed on the digital drainage system for the next 2 hours for determination of the size of the leak in cubic centimeters per minute. Comparisons between the air leak measurements of the two systems were made. These patients were then placed back to the Sahara system for the rest of the day and remained on the Sahara system unless an air leak was noted the next morning on rounds. If an air leak was noted, the same process was repeated each day. Similarly, if patients were randomized to the digital system and an air leak was detected on morning rounds, the size of the leak was recorded in cubic centimeters per minute and their tubes were then placed to the Sahara analogue system for the next 2 hours. The size and type of the leak was recorded using the RDC system, and again, comparisons were made between the two systems. The tubes were then placed back to the digital system for the remainder of the day. This enabled us to correlate the digital system s air leak data with the only verified and tested classification system for air leaks, the RDC classification system. Patients spent no more than 2 hours daily on the device different from the one they were randomized to receive in the operating room. Chest tubes were removed when the output was no greater than 450 cm 3 /day [18] and there was no presence of a discernible air leak on either system. The same criterion for chest tube removal was applied to both groups of patients. In addition to providing the size of the air leak with each breath in milliliters per minute, the digital system is also able to provide the mean air leak over the past several hours. The system can be calibrated for any length of time, but for this study we chose to calibrate the meter to provide the mean air leak over the previous 1, 3, and 6 hours. These numbers were chosen arbitrarily. In addition, the digital device is also able to generate intrapleural pressure curves which display the maximum and the minimum intrapleural pressures. These two sets of data were also recorded and used for air leak assessment, chest tube management, and interpretation of the physiology of the pleural space. Table 1. Patient Characteristics by Randomization a,b Variable Digivent (n 50) Sahara (n 50) p Value Age, median (range) y 61 (28 82) 63 (19 88) NA c Sex, No (%) NA c Male 25 (50) 26 (52) Female 25 (50) 24 (48) Procedure, No. (%) NA c Wedge or other 14 (28) 15 (30) thoracotomy Segmentectomy 7 (14) 9 (18) Lobectomy 29 (58) 26 (52) Pre-op pulmonary function FEV 1 % 76 73 0.67 MVV% 71 64 0.91 Dlco% 71 69 0.21 Dlco-adjusted% 76 82 0.37 Hx neoadjuvant therapy, 4 (8) 3 (6) 1.00 No. (%) Malignant disease 42 (84) 43 (86) 1.00 Benign disease 8 (16) 7 (14) 1.00 397 a Sahara S-11000, Teleflex, Research Triangle Plus, NC. b Digivent, Millicore, Sweden. c Not applicable because patients were matched on these variables. Dlco diffusion capacity of the lung for carbon monoxide; FEV 1 % forced expiratory volume in 1 second; Hx history; MVV maximum voluntary ventilation. GENERAL THORACIC

GENERAL THORACIC 398 CERFOLIO AND BRYANT Ann Thorac Surg AIR LEAKS: CONTINUOUS AND DIGITAL MONITORING 2008;86:396 401 Table 2. Outcomes According to Randomization Outcome Digivent a (n 50) Sahara b (n 50 p Value Chest tubes, mean No. 1 1 NA Post-op air leak, No. Day 1 23 21 NA Day 2 11 10 NA Day 3 6 5 NA Patients discharged home 3 4 0.942 on device, No. Chest tube removal, 3.1 3.9 0.034 mean day Hospital length of stay, days 3.3 4.0 0.055 a Sahara S-11000, Teleflex, Research Triangle Plus, NC. Millicore, Sweden. Statistical Analysis Analysis was conducted using SAS 9.0 software (SAS Corporation, Cary, NC). Continuous data are presented as medians, and categoric data are presented as percentages. The Fisher exact test or the Pearson 2 test was used to assess categoric data and the Wilcoxon test to evaluate continuous variables. A two-sided value of p 0.05 was considered statistically significant and unlikely due to chance. A linear regression model was used to determine the correlation between the RDC and digital classification systems. Results Of the 100 patients in the study, 50 received the digital drainage system and 50 received the analogue device. Patient characteristics are reported in Table 1. There was no statistically significant difference between age, sex, or type of procedure performed because we matched for these characteristics. Table 2 summarizes the outcomes. It shows that those randomized to the digital device had Table 3. Comparison of Air Leaks Status, Type, and Size Between the Robert David Cerfolio Classification System and the Digital System Air Leak on RDC System Median Air Leak, Digital System, ml/min (range) b Digivent, Preferred or Recommended Chest Tube Setting a FE 1 to FE 3 100 (0 200) Water seal FE 3 to FE 5 400 (100 800) Water seal FE 6 to FE 7 850 (range, 10 1230) Water seal E 1 to E 3 1525 (220 1800) Water seal E 4 to E 6 1750 (675 2000) 10 cm suction E7 2000 20 cm suction b a Other factors affect chest tube setting such as the type of pulmonary resection, the compliance of the lung and the chest wall, the presence of a pneumothorax, or fixed pleural space deficit, among others. b Setting if pneumothorax or subcutaneous air, or both, are present. E expiratory; FE forced expiratory. Fig 1. Linear regression for Robert David Cerfolio (RDC; Sahara S-11000, Teleflex, Research Triangle Plus, NC]) system vs the digital (Digivent, Millicore, Sweden) system (r 2 0.80; regression equation: y 2.094 0.0061 x). (E expiratory; FE forced expiratory.) a slightly shorter duration of chest tube requirement and length of stay. The digital system confirmed the air leak status in 5 patients that were equivocal on the analogue system. Several patients were discharged home on postoperative day 4 with their chest tubes in place. Those randomized to the digital units went home with the Digivent. Those randomized to the Sahara system went home with an Atrium Express (Hudson, NH). Table 4. Satisfaction Ratings Variable Digivent, a No. (%) Sahara, b No. (%) Patient Easy to walk/move around with device? (POD 3) c Yes 42 (88) 44 (90) No 6 (12) 5 (10) Clinician Average time to rate air leak at bedside 30 seconds 39 (78) 14 (28) 30 60 seconds 7 (14) 26 (52) 60 seconds 4 (8) 10 (20) Degree of variability of air leak score d High 6 (12) 15 (30) Low 44 (88) 35 (70) Nursing staff Device setup Easy 6 (38) 16 (89) Difficult 10 (62) 2 (11) a Sahara S-11000, Teleflex, Research Triangle Plus, NC. b Digivent, Millicore, Sweden. c Responses were less than 100% because some patients did not respond or were discharged by this POD. d Determined by readings by 2 different individuals. POD postoperative day.

Ann Thorac Surg CERFOLIO AND BRYANT 2008;86:396 401 AIR LEAKS: CONTINUOUS AND DIGITAL MONITORING Patients whose air leaks resolved at home returned at 1 week to our clinic for chest tube removal. If the air leak was still present after 2 weeks at home, they returned to our clinic and all tubes were removed regardless of their air leak status. Patients who went home with the digital device were able to relate their air leaks status to us by telephone more easily than those with the analogue system. Table 3 reports the comparison of the size and type of an air leak using the analogue RDC classification system and its corresponding size on the new digital system. Figure 1 shows a moderately linear relationship (r 2 0.80) between the RDC (Sahara) system and the digital (Digivent) system. The preferred chest tube setting for the different types of leaks is also summarized in Table 3. Table 4 reports the patient and clinician satisfaction between the two different types of drainage and air leak systems. Comment In recent years, the assessment of many of our patients indicators, as well as many other parts of our every day lives, has used digital technology. Many signs at the bedside or in the intensive care unit, such as arterial or pulmonary blood pressure, heart rate, oxygen saturation, and temperature are reported continuously and digitally. This type of data recording has led to the more accurate assessment of the patient s condition and to the quicker implementation of therapy. However until now, the only way to report air leaks has been with analogue score and in an inherently subjective manner. This is because until recently no other way has been available to report the size or type of air leak as measured by a chest tube in the pleural space. Several companies have designed, developed, and recently marketed chest tube drainage systems that contain a digital air leak meter. One system, the Airfix (TEUPs Ltd, Deutschlandsberg, Austria), was only reported in one article [19], and we believe it was designed and used solely for that study and as academic tool to digital measure air leaks. Another system, the one used in our study, is the Digivent (Millicore, Stockholm, Sweden), which is currently being used in some hospitals in Europe and has United States Food and Drug Administration (FDA) approval in the United States. The third system, the Thopaz (Medela, Switzerland), is also being used in Europe and is undergoing FDA approval for use in the United States. In this clinical, randomized study, we evaluated the use of one of these new digital and continuous pleural monitoring systems compared with the analogue systems almost exclusively used today. It has been well chronicled that air leaks are common despite intraoperative maneuvers to help reduce or eliminate them. It has also been well shown that air leaks increase the hospital length of stay, increase cost, decrease patient satisfaction, and most importantly, increase morbidity. Thus, any technology that helps to increase our ability to treat alveolar pleural fistulas or air leaks in a scientific, objective manner has enormous clinical as well as cost-saving potential. 399 The ideal characteristics of a drainage system for chest tubes after pulmonary or chest surgery include a system that: provides a large reservoir for the collection and analysis of pleural effluent, is compact and easy for patients to ambulate while the tubes are in the chest, is latex free, quiet, is able to exert different levels of suction from at least 40 cm of wall suction reliably and continuously even as a patient walks if needed, to underwater seal, does not need to be replaced if tipped over, protects the patient from the collected fluid in the reservoir from entry retrograde back into the chest tubes, is reusable, can be emptied so it can be reused once full, can continuously, digitally, and accurately assess the size of an air leak, can continuously and digitally assess the amount of chest tube drainage in any desired time interval, can, if needed assess the hemoglobin or other chemical contents of the pleural effluent, can produced a written record of events in the pleural space as well as the size of the air leak, allows for the patient to be sent home on the same device if needed because of persistent leak or drainage without the need for a new device and air leak and drainage data can be transmitted to the physician s office electronically, and is inexpensive. No current system meets of all these qualities. The cost and features of each system may influence one to choose one type of system rather than another based on the chest operation that is performed, the surgeon s practice, and most importantly, the patient s clinical course. In this study we found that the digital system correlates with the only verified and proven air leak classification system available. As reported in Table 3, an air leak that was measured as larger by the RDC classification analogue scale was also measured as larger on the new unverified digital scale. This suggests the digital system is consistent with the only clinically verified measuring device. The most common type of leak, a forced expiratory 3 leak (FE-3), is about 400 ml/min on the digital scale. This study also demonstrated some advantages of the continuous and digital measurement of air leaks compared with the analogue system. First, it provides a more accurate assessment of the patient s air leak and was more reproducible between observers. In 2 patients, however, the digital controller unit seemed to get jammed and was consistently reading only 1 number. This required the system to be replaced by another air leak meter. Aside from these instances, the meter was accurate and reliable. GENERAL THORACIC

GENERAL THORACIC 400 CERFOLIO AND BRYANT Ann Thorac Surg AIR LEAKS: CONTINUOUS AND DIGITAL MONITORING 2008;86:396 401 The ability to obtain the size of the air leak with each breath was valuable. Perhaps the most important information was the ability to query the unit and quickly get the average size of the air leak during the past 1, 3, or 6 hours. This allows one to objectively see how the leak was sealing over time and whether the chest tube setting used over that timeframe was promoting sealing or hindering it. It also gave more confidence and assurance that the tube could be safely removed, because one could see that indeed the leak had been slowly getting smaller during the course of the day and was now gone. This is different from the current analogue systems that may have showed, for example, an air leak to be an E-2 in the morning on rounds, but no other readings are recorded during the day unless they are measured by someone who has to go to the bedside to make the observation. The digital system allows for anyone to read the number and report it to the physician without the worry of observer error. The system can provide information on the effectiveness of chest tube changes minute-byminute without the need for a physician to be at the bedside. Finally, we were able to send patients with prolonged air leaks (an air leak present on postoperative day 4) safely home on the digital device. They were able to tell us their air leak status over the telephone. Our preferred management of prolonged air leaks has long been to send patients home with a chest tube in place attached to an outpatient device [8]. We prefer this treatment rather than reoperation or bedside pleurodesis or blood patch. Reoperation is almost never indicated, and although pleurodesis or blood injection through the chest tube may at times be an effective therapy for prolonged or persistent leaks, it risks empyema. We now prefer outpatient self-contained compact devices rather than the Heimlich valve because they can collect the chest drainage and can provide more accurate air leak status information. This is especially true with the easier to read digital device. Despite the advantages shown in this prospective study of the digital system, the real question is the cost of the unit compared to the cost-savings it offers. In addition, the number of patients that would realize this potential cost-savings is unknown. Because most patients do not have air leaks, is the unit really needed for everyone? We and others have shown that most patients with air leaks can be managed, fast-tracked, and enjoy safe results with a postoperative stay of 3 or 4 days using the analogue system [20]. Currently the Digivent costs our hospital $250 per unit, whereas the Sahara S-11000 costs only $46. Perhaps, given this cost differential, the digital unit should be reserved for those patients who still that have an air leak on postoperative day 3 or 4, or for those who have air leaks that cannot be efficiently or accurately managed with the current less expensive analogue system. However, if it can decrease the length of stay by just 1 day it may more than pay for this difference. The pleural pressure curves provided by this particular digital system also provide unique and novel information. The true clinical importance of these curves and what it is truly measuring in the pleural space require further study. We have noted, however, that these curves unequivocally depict the actually sealing of air leaks; thus, they may serve as a guide for chest tube management. In addition, the pleural pressure curves may signal the development of a pneumothorax. Now, however, the only way to generate curves is to remove the controller unit, which sits on top of the digital pleural drainage system, and then connect it to a laptop computer and download the information. Thus, the clinical usefulness of this information on rounds, as well as the extra time required to obtain the information, remains unsupported. Further studies are needed and are well underway to better assess the clinical importance of these curves, Moreover, the actual physiologic meaning of these curves and of the maximum and minimum pleural pressures that the Digivent provides requires further investigation. This study has several limitations. First, the sample size is relatively small. Second, it is a single-center study. Third, the physicians were not blinded to which arm the patients were entered into. Although any single institutional study with just 1 surgeon limits confounders, a multi-institutional study is superior. Third, the decrease in length of stay is modest; however, it did achieve statistical significance. Given our aggressive fast-tracking postoperative algorithm that we already used with the patients in the analogue arm of this study, even the modest reduction seen in our practice in the length of stay is impressive. A digital system might have an even greater impact in the care of patients who have the more typical 6- or 7-day hospital stay after thoracotomy. The strengths of this study include its prospective randomized design, the use of 1 surgeon, and the fact that chest tubes were managed the same way in all patients and removed as soon as either system suggested the air leak was gone. The future of the digital and continuous assessment of air leaks is promising. It is, in our opinion, the future of air leak assessment and we believe will serve as the best guide for optimal chest tube management. Digital systems have eclipsed analogues systems in many facets of our lives, especially in medicine. It is unlikely that measurements of pleural space and air leaks would differ. Moreover, its full application has not yet been defined; for example, we have used the Digivent for several other patients. We applied the system to the chest tube of a patient that had undergone a right pneumonectomy and was thought to have a bronchopleural fistula immediately postoperatively because of a large swing in the balanced drainage system. The Digivent provided definitive, objective, and reproducible digital assessment of the pleural space and provided unequivocal evidence that there was no leak, thus saving the patient a reoperation. We also have used it to help guide the optimal subsegmental deployment of an endobronchial valve in an anticoagulated patient who had a persistent and large air leak after a trauma. The patient could not tolerate an open intervention, was requiring ventilator support, and was loosing large tidal volumes.

Ann Thorac Surg CERFOLIO AND BRYANT 2008;86:396 401 AIR LEAKS: CONTINUOUS AND DIGITAL MONITORING Finally, patients who are discharged home with the Digivent may in the future be able to transmit their pleural space information and air leak data to the physician electronically over telephone lines or the Internet. Air leaks, like so many other patient characteristics, are probably best monitored continuously and digitally. The Digivent units were provided by Millicore for this study. Statistical analysis and data entry were funded by Millicore. References 1. Rice TW, Kirby TTJ. Prolonged air leak. Chest Surg Clin North Am 1992;2:803 11. 2. Cerfolio RJ. Recent advances in the treatment of air leaks. Curr Opin Pulm Med 2005;11:319 23. 3. Cerfolio RJ. Advances in thoracostomy tube management. Surg Clin N Am 2002:82:833 48. 4. Fabian T, Federico JA, Ponn RB. Fibrin glue in pulmonary resection: a prospective, randomized, blinded study. Ann Thorac Surg 2003;75:1587 92. 5. Brunelli A, Monteverde M, Borri A, et al. Predictors of prolonged air leak after pulmonary lobectomy. Ann Thorac Surg 2004;77:1205 10. 6. Cerfolio RJ, Holman WL, Katholi CR. Pneumoperitoneum after concomitant resection of the right middle and lower lobes (bilobectomy). Ann Thorac Surg 2000;70:942 7. 7. Brunelli A, Al Refai M, Monteverde M, et al. Pleural tent after upper lobectomy: a randomized study of efficacy and duration of effect. Ann Thorac Surg 2002;74:1958 62. 8. Cerfolio RJ, Bass CS, Pask AH, Katholi CR. Predictors and treatment of persistent air leaks. Ann Thorac Surg 2002;73: 1727 31. 9. Cerfolio RJ, Bryant AS, Ojha B, Bartolucci AA. The maximum standardized uptake values on positron emission tomography of a non-small cell lung cancer predict stage, recurrence, and survival. J Thorac Cardiovasc Surg 2005;130:151 9. 401 10. Hawes RH, Gress F, Kesler KA, Cummings OW, Conces DJ Jr. Endoscopic ultrasound versus computed tomography in the evaluation of the mediastinum in patients with nonsmall-cell lung cancer. Endoscopy 1994;26:784 7. 11. Cerfolio RJ, Bryant AS, Eloubeidi MA. Routine mediastinoscopy and esophageal ultrasound fine-needle aspiration in patients with non-small cell lung cancer who are clinically N2 negative: a prospective study. Chest 2006;130:1791 5. 12. Eloubeidi MA, Cerfolio RJ, Chen VK, Cerfolio RJ. Endoscopic ultrasound-guided fine needle aspiration of mediastinal lymph nodes in patients with suspected lung cancer after positron emission tomography and computed tomography scans. Ann Thorac Surg 2005;79:263 8. 13. Cerfolio RJ, Bryant AS, Patel B, Bartolucci AA. Intercostal muscle flap reduces the pain of thoracotomy: a prospective randomized trial. J Thorac Cardiovasc Surg 2005;130:987 93. 14. Cerfolio RJ, Bryant AS, Bass CS, Bartolucci AA. A prospective, double-blinded, randomized trial evaluating the use of preemptive analgesia of the skin before thoracotomy. Ann Thorac Surg 2003;76:1055 8. 15. Cerfolio, Price T, Bryant AS, Sale Bass C, Bartolucci AA. Intracostal sutures decrease the pain of thoracotomy. Ann Thorac Surg 2003;76:407 11. 16. Cerfolio RJ, Bryant AS, Maniscalco LM. A nondivided intercostal muscle flap further reduces pain of thoracotomy: a prospective randomized trial. Ann Thorac Surg 2008;85: 1901 7. 17. Cerfolio RJ, Bass CS, Katholi CR. Propsectiove randomized trial compares suction versus water seal for air leaks. Ann Thorac Surg 2001;71:1613 7. 18. Cerfolio RJ, Bryant AS. Results of a prospective algorithm to remove chest tubes after pulmonary resection with high output. J Thorac Cardiovasc Surg 2008;135:269 73. 19. Anegg U, Lindenmann J, Matzi V, et al. AIRFIX: the first digital postoperative chest tube airflowmetry-a novel method to quantify air leakage after lung resection. Eur J Cardiothorac Surg 2006;29:867 72. 20. Cerfolio RJ, Pickens A, Bass C, Katholi C. Fast-tracking pulmonary resection. J Thorac Cardiovasc Surg 2001;122: 318 24. GENERAL THORACIC