Risk Factors Predisposing to Prolonged Air Leak After Video-Assisted Thoracoscopic Surgery for Spontaneous Pneumothorax Lei Jiang, MD, Gening Jiang, MD, Yuming Zhu, MD, Wang Hao, MD, and Lei Zhang, MD Department of Thoracic Surgery, Shanghai Pulmonary Hospital, Shanghai, China GENERAL THORACIC
Background. The goal of this prospective study was to determine risk factors for prolonged air leak (PAL) for patients who underwent video-assisted thoracoscopic surgery (VATS) for spontaneous pneumothorax. Methods. Between January 2002 and June 2012, a total of 2,292 patients were eligible for enrollment in the study: 1,800 patients had primary spontaneous pneumothorax and 492 patients had secondary spontaneous pneumothorax. There were 312 female and 1,980 male patients with a mean age of 41 years (range, 13 to 85 years). Twenty-three variables were recorded for each patient. The primary endpoint was rate of postoperative PAL (chest tube drainage for >7 days). Statistical evaluation used univariate and multivariate logistic regression analyses. Results. A total of 223 (9.73%) cases of postoperative PAL occurred in 2,292 patients. Comparing clinical characteristics between the patients with and without PAL, mean age in the air leak group (59 ± 18 y) was
significantly older than that in non-air-leak group (39 ± 18 y) (p < 0.05). Multivariate analyses found 4 variables related to PAL (p < 0.05): age, American Society of Anesthesiologists scores, bilateral procedures, and bullae diameter. No significant relationships were found between pleural abrasions and/or talc pleurodesis and PAL. Conclusions. Prolonged air leak is one of the most common complications after spontaneous pneumothorax operations. Age, American Society of Anesthesiologists scores, bilateral procedures, and bullae diameter were risk factors for PAL. Use of talc pleurodesis with pleural abrasion may not decrease the incidence of PAL in VATS spontaneous pneumothorax operation. Talc pleurodesis with pleural abrasion should be used cautiously in patients with significant comorbid conditions or advanced age.
S
(PAL) (>7 d). Thus decisions to operate and procedures of choice should be made on a case-by-case basis through generalized assessing of individual risk profiles to improve outcomes. The purpose of this study was to explore the risk factors for development of PAL after thoracoscopic operation in patients with spontaneous pneumothorax by using logistic regression; in this regard, surgeons can plan to apply preventive techniques to decrease the duration of chest drainage and postoperative hospitalization in highrisk populations.
pontaneous pneumothorax is a common entity in general thoracic operations that may develop recurrent episodes; video-assisted thoracoscopic surgery (VATS)—bullectomy with pleural abrasion—is a reliable and safe method to treat spontaneous pneumothorax. Long-term recurrences occur with an acceptable rate that compares with results after limited thoracotomy [1]. With an aging population, the number of older patients with spontaneous pneumothorax have grown rapidly, most of whom have secondary spontaneous pneumothorax (SSP). Older patients usually also have substantial comorbid diseases, such as emphysema, giant and diffuse bullae, chronic obstructive pulmonary disease (COPD), and pulmonary dysfunction. These conditions significantly increase the difficulty of the operations, and postoperative complication rates in patients aged 70 years or older are much higher than those in younger patients, especially postoperative prolonged air leak Accepted for publication Oct 11, 2013. Address correspondence to Dr Zhang, Department of Thoracic Surgery, Shanghai Tongji University affiliated Shanghai Pulmonary Hospital, No. 507 Zhengming Rd, Shanghai, China 200433; e-mail: [email protected].
Ó 2014 by The Society of Thoracic Surgeons Published by Elsevier Inc
(Ann Thorac Surg 2014;97:1008–14) Ó 2014 by The Society of Thoracic Surgeons
Patients and Methods We performed a retrospective study of all patients who underwent VATS bullectomy or bullae ligature for spontaneous pneumothorax at Shanghai Tongji University affiliated Shanghai Pulmonary Hospital between January 2002 and June 2012. A total of 2,292 patients were eligible for enrollment in the study: 1,800 patients had primary spontaneous pneumothorax (PSP) and 492 patients had SSP. The study was reviewed and approved by the Institutional Ethical Committee and individual patient consent was waived. 0003-4975/$36.00 http://dx.doi.org/10.1016/j.athoracsur.2013.10.031
Ann Thorac Surg 2014;97:1008–14
ASA = American Society of Anesthesiologists COPD = chronic obstructive pulmonary disease FEV1 = forced expiratory volume in 1 second FVC = forced vital capacity PaCO2 = arterial partial pressure of carbon dioxide PAL = prolonged air leak PaO2 = arterial partial pressure of oxygen POD = postoperative day PSP = primary spontaneous pneumothorax SaO2 = oxygen saturation SSP = secondary spontaneous pneumothorax VATS = video-assisted thoracoscopic surgery
The surgical indications included were as follows: (1) recurrent spontaneous pneumothorax on the same side; (2) closed drainage for pneumothorax lasted longer than 2 weeks; (3) ipsilateral lung expanded poorly with residual space larger than the volume of 30% thoracic cavity; (4) spontaneous pneumothorax complicated by giant bullae (>50% of the hemithorax); (5) job restrictions or patients’ individual requirements; (6) postoperative recurrent spontaneous pneumothorax. Exclusion criteria included patients who had spontaneous pneumothorax with empyema, tuberculosis, pulmonary infections, malignant tumors, or hemopneumothorax, or those who had lobectomy or pneumonectomy. There were 312 female and 1,980 male patients with a mean age of 41.49 years (range, 13 to 85 years). Pathology postoperatively confirmed blebs/bullae in all specimens. A clinical diagnosis of COPD was considered in any patient who has dyspnea, chronic cough or sputum production, and/or a history of exposure to risk factors for the disease. The diagnosis was confirmed by spirometry. The presence of a postbronchodilator ratio of forced expiratory volume in 1 second to forced vital capacity (FEV1/ FVC) less than 0.70 and FEV1 less than 80% predicted was used to confirm the presence of airflow limitation that is not fully reversible. The following parameters were determined: patient age and sex, Brinkman index (defined by the cigarettes smoked per day total years of smoking), comorbidity, blood tests, arterial blood gas analysis, chest computed tomography scans, American Society of Anesthesiologists (ASA) scores, years of operation, surgical management (bullectomy, bullae ligature, talc pleurodesis, pleural abrasion, reoperation for recurrent spontaneous pneumothorax, bilateral procedures), operative time, intraoperative blood loss, bullae diameters and distributions, chest drainage volume, duration of pleural drainage, hospital stay, morbidity, and mortality. The primary endpoint was rate of postoperative PAL (chest tube drainage for >7 days). Follow-up information was obtained from the hospital case records, from a
1009
questionnaire completed by the chest physician, or from death certificates.
Surgical Care After achievement of general anesthesia by using a double-lumen endotracheal tube, a 30-degree, 5-mm thoracoscope was placed through the seventh or eighth intercostal space in the midaxillary line, and one access port (fourth intercostal space in the anterior axillary line) or two access ports (one as before, one in posterior axillary line of the sixth intercostal space) were placed at the surgeon’s discretion. The choice of specific surgical approach was dictated based on the characteristics of bullae, the extent of pleural adhesions, and the underlying pleural or pulmonary parenchymal diseases. VATS bullectomy was performed in 2,072 patients whose bullae or apical portions of diseased lung were removed in a wedge fashion using an Endopath GIA stapler (Ethicon Endo-Surgery, Cincinnati, OH); the staple line was never reinforced with a pericardial strip. Video-assisted thoracoscopic surgery bullae ligature was undertaken in 220 patients because of diffuse bullae, dense adhesions, or obscure demarcation between bullae and severe emphysematous lungs; the stapler could not be applied in these settings as may be used in a bullectomy. A minithoracotomy of 4 to 5 cm was made at the fourth intercostal space in the anterior axillary line for direct visual and handling access during VATS bullae ligature, and then direct ligature or suture was used to completely eradicate the bullae. We classified bullae, according to distribution of their location, into one of four categories: type I, single bulla; type II, multiple bullae all in the same lobe; type III, multiple bullae in two or more lobes; type IV, diffuse bullae. Bullae diameter was defined as the maximal diameter of the largest bullae measured as completely expanded. Mean operative time was 89.19 44.16 min for all patients (range, 30 to 350 min), and bleeding amount during the operation was a mean of 234.24 169.72 mL (range, 20 to 2,300 mL). Two chest drainage tubes were routinely placed in the thoracic cavity after operations, and suction drainage could be applied with no Heimlich valve if the lung was partially expanded.
Statistics Continuous data are presented as means standard deviation, differences between continuous variables were measured by the two-tailed Student’s t test; categoric data are presented as counts followed by percentages in parentheses, and analyzed by using the c2 or Fisher exact tests; statistical significance was accepted as p < 0.05. Univariate and multiple logistic regression analyses were used to explore the risk factors for development of PAL. Variables significantly related to the unfavorable outcomes in univariate analysis were considered in multivariate analysis with forward selection and backward elimination using PAL as an endpoint. All data analysis was performed with SPSS software (SPSS 15.0 for Windows, SPSS Inc, Chicago, IL).
GENERAL THORACIC
Abbreviations and Acronyms
JIANG ET AL RISK FACTORS FOR PROLONGED AIR LEAK
1010
JIANG ET AL RISK FACTORS FOR PROLONGED AIR LEAK
Results
GENERAL THORACIC
A total of 223 (9.73%) cases of postoperative PAL occurred in 2,292 patients, and 9 (0.39%) patients died of postoperative pulmonary and/or other organ failure, of whom 6 had PAL. Mean time of chest drainage in 223 patients was 16.63 15.97 days, and the longest time was 130 days; 3 patients underwent reoperations for repair of leak sites, and all chest tubes were removed after repair. Comparing clinical characteristics between the patients with and without PAL, which were summarized in Table 1, mean age in the air leak group (59.35 18.03 y) was significantly older than that in the non-air-leak group (39.48 17.75 y) (p < 0.05). PAL rates in PSP and SSP patients were 3.8% and 31.3%, respectively (p < 0.05). Patients with COPD had a significant higher rate (44.0%) of PAL than patients without COPD (6.45%; p < 0.05). PAL rates were 5.0%, 53.9%, 93.7% in ASA-I, ASA-II, and ASA-III patients, respectively (p < 0.05); bilateral procedures were associated with a higher air leak rate compared with unilateral procedures, 20.9% versus 9.4% (p < 0.05). There was an association between bullae diameters and PAL rates, with the mean diameter in the airleak group (8.41 4.04 cm) significant larger than that in non-air-leak group (4.68 3.07 cm) (p < 0.05); according to distribution of bullae location, the PAL rates in each group from type I to type IV were 2.8%, 3.3%, 8.1%, and 29.25%, respectively. However, we did not see an association between PAL and use of talc pleurodesis and pleural abrasion. In the univariate analyses in the logistic regression tests, statistical differences were found for age, COPD, ASA scores, SSP, bilateral procedures, bullae diameter, and bullae distribution (p < 0.05) (Table 2). When these factors were entered into multivariate analysis, four variables (age, ASA scores, bilateral procedures, and bullae diameter) were found to be independently associated with PAL (p < 0.05) (Table 3).
Comment Spontaneous pneumothorax can occur in every age group, and each age group has its own clinical characteristics, although all patients present with the accumulation of air in the pleural space. Primary spontaneous pneumothorax occurs mainly in otherwise healthy people (mainly tall and thin young men) without any clinical sign of lung disease. In contrast, SSP occurs mostly in patients with diagnosed and clinically manifested lung disease and is most frequent in older subjects. In the patients with SSP, we found significantly more prolonged postoperative air leaks and longer postoperative chest tube drainage time [2]. Video-assisted thoracoscopic surgery is effective in the surgical treatment of PSP and SSP, although the technical difficulty, morbidity rate, hospital stay, and incidence of persistences and recurrences are greater with SSP than with PSP [3]. Thus treatment needs to be individually determined based on the clinical situation, in order to decrease the incidence of postoperative complications.
Ann Thorac Surg 2014;97:1008–14
Prolonged air leak is one of the most common complications after spontaneous pneumothorax operations, with rates of 6.1% to 15.6% reported in the literature [1, 4–7]. This study summarized 2,292 patients undergoing VATS operations for spontaneous pneumothorax during a period of 10 years; the overall postoperative PAL rate was 9.73%. With a view to lower complications as much as possible, this study used univariate and multivariate logistic regression analysis to assess records from patients with spontaneous pneumothorax for relevant preoperative and operative variables that may be associated with postoperative PAL, to dtermine risk factors predisposing patients to PAL after VATS. In the univariate logistic regression tests, statistical differences were found for seven variables associated with PAL, including age, COPD, ASA scores, SSP, bilateral procedures, bullae diameter, and bullae distribution. As multiple factors may contribute to the development of PAL, a multivariate analysis was necessary to define which factors carried independent prognostic value, and which ones were merely associated with other, more important prognostic factors. Hence the seven factors were entered into multivariate analysis, and only four variables (age, ASA scores, bilateral procedures, and bullae diameter) were found to be independent factors of PAL. Classifying all patients into three age groups, we found the incidences of PAL in patients aged 13 to 49 years, 50 to 69 years, and 70 to 85 years to be 3.55%, 13.1%, and 49.1%, respectively. Thus, the rates of PAL increased with increasing age. With the patients’ age increasing, ever more patients had chronic pulmonary diseases, such as severe emphysema, COPD, diffuse and/or confluent giant bullae, parenchymal consolidation and calcification, and extensive dense pleural adhesions. These conditions are often accompanied by decreased pulmonary function and physical activity, even other organ dysfunction. The patient’s global status was quantified objectively by ASA scores. In the age group 13 to 49 years, operative risk was scored as ASA-I in 99.6% of patients and as ASA-II in 0.4% of patients; in the age group 50 to 69 years, ASA-II accounted for 9.5% of patients and ASA-III accounted for 0.9% of patients; and in the age group 70 to 85 years, ASA-II and ASA-III accounted for 55.9% and 15.7% of patients, respectively. Patients undergoing bilateral procedures usually have good medical fitness without the above-mentioned variables, yet still had a higher PAL rate, from 16.5% to 20% [8, 9]. PAL may occur as a result of compromised pulmonary reexpansion and persistent residual space, because postoperative pain caused by bilateral thoracotomy and chest tube drainage adversely affect respiratory movement and effective expectoration and early ambulation. Therefore, a better understanding of the mechanisms inherent to PAL, coupled with strategies targeting pathophysiological characteristics of high-risk patients, may reduce the incidence of this complication. Thoracoscopic simple bullectomy for spontaneous pneumothorax has a relatively high postoperative recurrence rate and
Ann Thorac Surg 2014;97:1008–14
JIANG ET AL RISK FACTORS FOR PROLONGED AIR LEAK
1011
Variables Sex, male, n (%) Age, mean SD (years) Age subgroups, n (%) 49 y 50–69 y 70 y Smokers, n (%) Brinkman index,b mean SD Preoperative hemoglobin, mean SD (g/L) Preoperative albumin, mean SD (g/L) Preoperative SaO2, mean SD (%) Preoperative PaO2, mean SD (kPa) Preoperative PaCO2, mean SD (kPa) COPD, n (%) PSP, n (%) ASA scores, n (%) I II III Operation years, n (%) 2002–2007 2008–2012 Operation types, n (%) Thoracoscopic bullectomy Thoracoscopic bullae ligature Talc pleurodesis Pleural abrasion Reoperation for recurrence Bilateral procedures Operative time, mean SD (min) Intraoperative blood loss, mean SD (mL) Bullae distribution,c n (%) I II III IV Bullae diameter, mean SD (cm) Drainage volume on POD 0, mean SD (mL) Duration of pleural drainage, mean SD (d) Postoperative hospital stay, mean SD (d) Mortality, n (%)
Patients With PAL (n ¼ 223)
Patients Without PAL (n ¼ 2,069)
p Valuea
194 (86.9) 59.35 18.03
1,786 (86.3) 39.48 17.75
0.780
Background. The goal of this prospective study was to determine risk factors for prolonged air leak (PAL) for patients who underwent video-assisted thoracoscopic surgery (VATS) for spontaneous pneumothorax. Methods. Between January 2002 and June 2012, a total of 2,292 patients were eligible for enrollment in the study: 1,800 patients had primary spontaneous pneumothorax and 492 patients had secondary spontaneous pneumothorax. There were 312 female and 1,980 male patients with a mean age of 41 years (range, 13 to 85 years). Twenty-three variables were recorded for each patient. The primary endpoint was rate of postoperative PAL (chest tube drainage for >7 days). Statistical evaluation used univariate and multivariate logistic regression analyses. Results. A total of 223 (9.73%) cases of postoperative PAL occurred in 2,292 patients. Comparing clinical characteristics between the patients with and without PAL, mean age in the air leak group (59 ± 18 y) was
significantly older than that in non-air-leak group (39 ± 18 y) (p < 0.05). Multivariate analyses found 4 variables related to PAL (p < 0.05): age, American Society of Anesthesiologists scores, bilateral procedures, and bullae diameter. No significant relationships were found between pleural abrasions and/or talc pleurodesis and PAL. Conclusions. Prolonged air leak is one of the most common complications after spontaneous pneumothorax operations. Age, American Society of Anesthesiologists scores, bilateral procedures, and bullae diameter were risk factors for PAL. Use of talc pleurodesis with pleural abrasion may not decrease the incidence of PAL in VATS spontaneous pneumothorax operation. Talc pleurodesis with pleural abrasion should be used cautiously in patients with significant comorbid conditions or advanced age.
S
(PAL) (>7 d). Thus decisions to operate and procedures of choice should be made on a case-by-case basis through generalized assessing of individual risk profiles to improve outcomes. The purpose of this study was to explore the risk factors for development of PAL after thoracoscopic operation in patients with spontaneous pneumothorax by using logistic regression; in this regard, surgeons can plan to apply preventive techniques to decrease the duration of chest drainage and postoperative hospitalization in highrisk populations.
pontaneous pneumothorax is a common entity in general thoracic operations that may develop recurrent episodes; video-assisted thoracoscopic surgery (VATS)—bullectomy with pleural abrasion—is a reliable and safe method to treat spontaneous pneumothorax. Long-term recurrences occur with an acceptable rate that compares with results after limited thoracotomy [1]. With an aging population, the number of older patients with spontaneous pneumothorax have grown rapidly, most of whom have secondary spontaneous pneumothorax (SSP). Older patients usually also have substantial comorbid diseases, such as emphysema, giant and diffuse bullae, chronic obstructive pulmonary disease (COPD), and pulmonary dysfunction. These conditions significantly increase the difficulty of the operations, and postoperative complication rates in patients aged 70 years or older are much higher than those in younger patients, especially postoperative prolonged air leak Accepted for publication Oct 11, 2013. Address correspondence to Dr Zhang, Department of Thoracic Surgery, Shanghai Tongji University affiliated Shanghai Pulmonary Hospital, No. 507 Zhengming Rd, Shanghai, China 200433; e-mail: [email protected].
Ó 2014 by The Society of Thoracic Surgeons Published by Elsevier Inc
(Ann Thorac Surg 2014;97:1008–14) Ó 2014 by The Society of Thoracic Surgeons
Patients and Methods We performed a retrospective study of all patients who underwent VATS bullectomy or bullae ligature for spontaneous pneumothorax at Shanghai Tongji University affiliated Shanghai Pulmonary Hospital between January 2002 and June 2012. A total of 2,292 patients were eligible for enrollment in the study: 1,800 patients had primary spontaneous pneumothorax (PSP) and 492 patients had SSP. The study was reviewed and approved by the Institutional Ethical Committee and individual patient consent was waived. 0003-4975/$36.00 http://dx.doi.org/10.1016/j.athoracsur.2013.10.031
Ann Thorac Surg 2014;97:1008–14
ASA = American Society of Anesthesiologists COPD = chronic obstructive pulmonary disease FEV1 = forced expiratory volume in 1 second FVC = forced vital capacity PaCO2 = arterial partial pressure of carbon dioxide PAL = prolonged air leak PaO2 = arterial partial pressure of oxygen POD = postoperative day PSP = primary spontaneous pneumothorax SaO2 = oxygen saturation SSP = secondary spontaneous pneumothorax VATS = video-assisted thoracoscopic surgery
The surgical indications included were as follows: (1) recurrent spontaneous pneumothorax on the same side; (2) closed drainage for pneumothorax lasted longer than 2 weeks; (3) ipsilateral lung expanded poorly with residual space larger than the volume of 30% thoracic cavity; (4) spontaneous pneumothorax complicated by giant bullae (>50% of the hemithorax); (5) job restrictions or patients’ individual requirements; (6) postoperative recurrent spontaneous pneumothorax. Exclusion criteria included patients who had spontaneous pneumothorax with empyema, tuberculosis, pulmonary infections, malignant tumors, or hemopneumothorax, or those who had lobectomy or pneumonectomy. There were 312 female and 1,980 male patients with a mean age of 41.49 years (range, 13 to 85 years). Pathology postoperatively confirmed blebs/bullae in all specimens. A clinical diagnosis of COPD was considered in any patient who has dyspnea, chronic cough or sputum production, and/or a history of exposure to risk factors for the disease. The diagnosis was confirmed by spirometry. The presence of a postbronchodilator ratio of forced expiratory volume in 1 second to forced vital capacity (FEV1/ FVC) less than 0.70 and FEV1 less than 80% predicted was used to confirm the presence of airflow limitation that is not fully reversible. The following parameters were determined: patient age and sex, Brinkman index (defined by the cigarettes smoked per day total years of smoking), comorbidity, blood tests, arterial blood gas analysis, chest computed tomography scans, American Society of Anesthesiologists (ASA) scores, years of operation, surgical management (bullectomy, bullae ligature, talc pleurodesis, pleural abrasion, reoperation for recurrent spontaneous pneumothorax, bilateral procedures), operative time, intraoperative blood loss, bullae diameters and distributions, chest drainage volume, duration of pleural drainage, hospital stay, morbidity, and mortality. The primary endpoint was rate of postoperative PAL (chest tube drainage for >7 days). Follow-up information was obtained from the hospital case records, from a
1009
questionnaire completed by the chest physician, or from death certificates.
Surgical Care After achievement of general anesthesia by using a double-lumen endotracheal tube, a 30-degree, 5-mm thoracoscope was placed through the seventh or eighth intercostal space in the midaxillary line, and one access port (fourth intercostal space in the anterior axillary line) or two access ports (one as before, one in posterior axillary line of the sixth intercostal space) were placed at the surgeon’s discretion. The choice of specific surgical approach was dictated based on the characteristics of bullae, the extent of pleural adhesions, and the underlying pleural or pulmonary parenchymal diseases. VATS bullectomy was performed in 2,072 patients whose bullae or apical portions of diseased lung were removed in a wedge fashion using an Endopath GIA stapler (Ethicon Endo-Surgery, Cincinnati, OH); the staple line was never reinforced with a pericardial strip. Video-assisted thoracoscopic surgery bullae ligature was undertaken in 220 patients because of diffuse bullae, dense adhesions, or obscure demarcation between bullae and severe emphysematous lungs; the stapler could not be applied in these settings as may be used in a bullectomy. A minithoracotomy of 4 to 5 cm was made at the fourth intercostal space in the anterior axillary line for direct visual and handling access during VATS bullae ligature, and then direct ligature or suture was used to completely eradicate the bullae. We classified bullae, according to distribution of their location, into one of four categories: type I, single bulla; type II, multiple bullae all in the same lobe; type III, multiple bullae in two or more lobes; type IV, diffuse bullae. Bullae diameter was defined as the maximal diameter of the largest bullae measured as completely expanded. Mean operative time was 89.19 44.16 min for all patients (range, 30 to 350 min), and bleeding amount during the operation was a mean of 234.24 169.72 mL (range, 20 to 2,300 mL). Two chest drainage tubes were routinely placed in the thoracic cavity after operations, and suction drainage could be applied with no Heimlich valve if the lung was partially expanded.
Statistics Continuous data are presented as means standard deviation, differences between continuous variables were measured by the two-tailed Student’s t test; categoric data are presented as counts followed by percentages in parentheses, and analyzed by using the c2 or Fisher exact tests; statistical significance was accepted as p < 0.05. Univariate and multiple logistic regression analyses were used to explore the risk factors for development of PAL. Variables significantly related to the unfavorable outcomes in univariate analysis were considered in multivariate analysis with forward selection and backward elimination using PAL as an endpoint. All data analysis was performed with SPSS software (SPSS 15.0 for Windows, SPSS Inc, Chicago, IL).
GENERAL THORACIC
Abbreviations and Acronyms
JIANG ET AL RISK FACTORS FOR PROLONGED AIR LEAK
1010
JIANG ET AL RISK FACTORS FOR PROLONGED AIR LEAK
Results
GENERAL THORACIC
A total of 223 (9.73%) cases of postoperative PAL occurred in 2,292 patients, and 9 (0.39%) patients died of postoperative pulmonary and/or other organ failure, of whom 6 had PAL. Mean time of chest drainage in 223 patients was 16.63 15.97 days, and the longest time was 130 days; 3 patients underwent reoperations for repair of leak sites, and all chest tubes were removed after repair. Comparing clinical characteristics between the patients with and without PAL, which were summarized in Table 1, mean age in the air leak group (59.35 18.03 y) was significantly older than that in the non-air-leak group (39.48 17.75 y) (p < 0.05). PAL rates in PSP and SSP patients were 3.8% and 31.3%, respectively (p < 0.05). Patients with COPD had a significant higher rate (44.0%) of PAL than patients without COPD (6.45%; p < 0.05). PAL rates were 5.0%, 53.9%, 93.7% in ASA-I, ASA-II, and ASA-III patients, respectively (p < 0.05); bilateral procedures were associated with a higher air leak rate compared with unilateral procedures, 20.9% versus 9.4% (p < 0.05). There was an association between bullae diameters and PAL rates, with the mean diameter in the airleak group (8.41 4.04 cm) significant larger than that in non-air-leak group (4.68 3.07 cm) (p < 0.05); according to distribution of bullae location, the PAL rates in each group from type I to type IV were 2.8%, 3.3%, 8.1%, and 29.25%, respectively. However, we did not see an association between PAL and use of talc pleurodesis and pleural abrasion. In the univariate analyses in the logistic regression tests, statistical differences were found for age, COPD, ASA scores, SSP, bilateral procedures, bullae diameter, and bullae distribution (p < 0.05) (Table 2). When these factors were entered into multivariate analysis, four variables (age, ASA scores, bilateral procedures, and bullae diameter) were found to be independently associated with PAL (p < 0.05) (Table 3).
Comment Spontaneous pneumothorax can occur in every age group, and each age group has its own clinical characteristics, although all patients present with the accumulation of air in the pleural space. Primary spontaneous pneumothorax occurs mainly in otherwise healthy people (mainly tall and thin young men) without any clinical sign of lung disease. In contrast, SSP occurs mostly in patients with diagnosed and clinically manifested lung disease and is most frequent in older subjects. In the patients with SSP, we found significantly more prolonged postoperative air leaks and longer postoperative chest tube drainage time [2]. Video-assisted thoracoscopic surgery is effective in the surgical treatment of PSP and SSP, although the technical difficulty, morbidity rate, hospital stay, and incidence of persistences and recurrences are greater with SSP than with PSP [3]. Thus treatment needs to be individually determined based on the clinical situation, in order to decrease the incidence of postoperative complications.
Ann Thorac Surg 2014;97:1008–14
Prolonged air leak is one of the most common complications after spontaneous pneumothorax operations, with rates of 6.1% to 15.6% reported in the literature [1, 4–7]. This study summarized 2,292 patients undergoing VATS operations for spontaneous pneumothorax during a period of 10 years; the overall postoperative PAL rate was 9.73%. With a view to lower complications as much as possible, this study used univariate and multivariate logistic regression analysis to assess records from patients with spontaneous pneumothorax for relevant preoperative and operative variables that may be associated with postoperative PAL, to dtermine risk factors predisposing patients to PAL after VATS. In the univariate logistic regression tests, statistical differences were found for seven variables associated with PAL, including age, COPD, ASA scores, SSP, bilateral procedures, bullae diameter, and bullae distribution. As multiple factors may contribute to the development of PAL, a multivariate analysis was necessary to define which factors carried independent prognostic value, and which ones were merely associated with other, more important prognostic factors. Hence the seven factors were entered into multivariate analysis, and only four variables (age, ASA scores, bilateral procedures, and bullae diameter) were found to be independent factors of PAL. Classifying all patients into three age groups, we found the incidences of PAL in patients aged 13 to 49 years, 50 to 69 years, and 70 to 85 years to be 3.55%, 13.1%, and 49.1%, respectively. Thus, the rates of PAL increased with increasing age. With the patients’ age increasing, ever more patients had chronic pulmonary diseases, such as severe emphysema, COPD, diffuse and/or confluent giant bullae, parenchymal consolidation and calcification, and extensive dense pleural adhesions. These conditions are often accompanied by decreased pulmonary function and physical activity, even other organ dysfunction. The patient’s global status was quantified objectively by ASA scores. In the age group 13 to 49 years, operative risk was scored as ASA-I in 99.6% of patients and as ASA-II in 0.4% of patients; in the age group 50 to 69 years, ASA-II accounted for 9.5% of patients and ASA-III accounted for 0.9% of patients; and in the age group 70 to 85 years, ASA-II and ASA-III accounted for 55.9% and 15.7% of patients, respectively. Patients undergoing bilateral procedures usually have good medical fitness without the above-mentioned variables, yet still had a higher PAL rate, from 16.5% to 20% [8, 9]. PAL may occur as a result of compromised pulmonary reexpansion and persistent residual space, because postoperative pain caused by bilateral thoracotomy and chest tube drainage adversely affect respiratory movement and effective expectoration and early ambulation. Therefore, a better understanding of the mechanisms inherent to PAL, coupled with strategies targeting pathophysiological characteristics of high-risk patients, may reduce the incidence of this complication. Thoracoscopic simple bullectomy for spontaneous pneumothorax has a relatively high postoperative recurrence rate and
Ann Thorac Surg 2014;97:1008–14
JIANG ET AL RISK FACTORS FOR PROLONGED AIR LEAK
1011
Variables Sex, male, n (%) Age, mean SD (years) Age subgroups, n (%) 49 y 50–69 y 70 y Smokers, n (%) Brinkman index,b mean SD Preoperative hemoglobin, mean SD (g/L) Preoperative albumin, mean SD (g/L) Preoperative SaO2, mean SD (%) Preoperative PaO2, mean SD (kPa) Preoperative PaCO2, mean SD (kPa) COPD, n (%) PSP, n (%) ASA scores, n (%) I II III Operation years, n (%) 2002–2007 2008–2012 Operation types, n (%) Thoracoscopic bullectomy Thoracoscopic bullae ligature Talc pleurodesis Pleural abrasion Reoperation for recurrence Bilateral procedures Operative time, mean SD (min) Intraoperative blood loss, mean SD (mL) Bullae distribution,c n (%) I II III IV Bullae diameter, mean SD (cm) Drainage volume on POD 0, mean SD (mL) Duration of pleural drainage, mean SD (d) Postoperative hospital stay, mean SD (d) Mortality, n (%)
Patients With PAL (n ¼ 223)
Patients Without PAL (n ¼ 2,069)
p Valuea
194 (86.9) 59.35 18.03
1,786 (86.3) 39.48 17.75
0.780
