Asian Cardiovasc Thorac Ann 2000;8:398-402
© 2000 Asia Publishing EXchange Pte Ltd
Early Management of the Postpneumonectomy Space
A Thomas Pezzella, MD,
A Alan Conlan, MD,
Gerald J Carroll, MD
Division of Cardiothoracic Surgery
University of Massachusetts Medical Center
Worcester, Massachusetts, USA
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For reprint information contact:A Thomas Pezzella, MD Tel: 1 605 399 4810 Fax: 1 605 399 0878 email: tpezzella{at}rcrh.orgDepartment of Cardiovascular Surgery & Medicine, Rapid City Regional Hospital, 2880 Fifth Street, Rapid City, SD 57701, USA.
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Abstract
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A contemporary presentation of the methods of early management of the postpneumonectomy space stresses anatomic and physiological principles. The advantages and disadvantages of each method are discussed.
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Introduction
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Open thoracotomy with positive endotracheal ventilatory support remains the standard operative technique for access to the thoracic cavity with maintenance of respiratory function. Closed drainage of air and fluid postoperatively, usually with suction at a pressure below 20 cm of water, ensures the gradual resumption of negative intrathoracic pressure. With lung resection, the primary objective is to allow the remaining lung to expand gradually and fill the hemithorax as well as reestablish the negative pressure of the intrathoracic space. The postpneumonectomy space is a different environment. The initially positive pressure of the space eventually becomes neutral as air is absorbed and the space fills with fluid. The contralateral lung gradually expands, pushing the mediastinum towards the operated side. In the normal state or in an extubated patient, the mediastinum is very mobile and acute or sudden shifts may compromise hemodynamic function. Ultimately, the shifted mediastinum, elevated hemi-diaphragm, and narrowed intercostal spaces, along with proliferation of the parietal pleura, partially obliterate the space with little fluid or fibroblast-impregnated material remaining. The early management of this space includes drainage and non-drainage techniques. This review highlights current approaches to management of the early postpneumonectomy space, with emphasis on avoiding acute mediastinal shifts and monitoring air and fluid changes.
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Routine Postthoracotomy Drainage
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Munnell has nicely reviewed the entire subject of thoracic drainage.1,2 The restoration of a negative intrathoracic environment following positive atmospheric entry with open thoracotomy is accomplished with a closed chest tube watersealed drainage system and negative suction at a pressure of 10 to 20 cm of water. Suction enhances the speed of evacuation of air or fluid. A 1-bottle system without suction provides a one-way egress of fluid and air from the closed chest cavity (Figure 1
). It is important to note that an increased water and fluid level requires a higher intrathoracic positive pressure to displace further air and fluid. This is compensated for by raising the underwater tube in the collecting chamber to maintain a 2-cm tube depth. This can be obviated with the independent 2-bottle collection system (Figure 2). This system, without suction, allows separate collection of the fluid without compromising the waterseal level. The 3-bottle system adds controlled suction to the 2-bottle system (Figure 3A). The commonly used plastic disposable system incorporates and modifies the 3-bottle system (Figure 3B). Once again, the goal of these systems is to allow the remaining lung parenchyma to expand and fill the hemithorax and restore negative pressure in the intrathoracic environment.
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Figure 1. Simple 1-bottle system without suction. Increased drainage requires adjustment of the waterseal tube.
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Figure 2. Two-bottle system without suction allows separate fluid collection. Waterseal level is unaffected.
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Figure 3. (A) Three-bottle system allows separate collection and the use of suction. (B) This self-contained disposable plastic system is a 3-bottle system.
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Early Postpneumonectomy Space
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The following descriptions encompass the commonly used systems, along with mention of uncommon approaches.
No Drainage
No drainage is the standard protocol in routine un-complicated pneumonectomy, either right- or left-sided. Following pneumonectomy, the surgical incision is closed in layers, a dressing is applied, and the patient is placed in the supine position. The location of the trachea is assessed along with the cardiac apical impulse. This documents the location of the mediastinum, which is confirmed by examination of the immediate postoperative chest radiograph. Deviation of the trachea to the operated side implies a negative-pressure space with hyper-expansion of the remaining lung. Deviation towards the nonoperated side implies a positive pressure in the empty space and a shift of the mediastinum to the nonoperated side. Prior to extubation, using a 50-cc syringe with a 3-way stopcock, an 18-gauge needle, or a 16-gauge plastic catheter is placed in the second or third interspace in the midclavicular line on the operated side, and 500 to 1000 mL of air is aspirated slowly. Resistance to aspiration is met as the mediastinum shifts to the operated side. The goal is to keep the trachea in the midline. Occasionally, if the trachea shifts to the operated side because of increased negative pressure, it may be necessary to inject air rather than aspirate it, to allow a more gradual shift of the mediastinum and avoid torsion of the mediastinal structures, namely the heart and systemic veins. In 2 to 3 days, the mediastinum stabilizes. The clinical and radiographic pictures dictate subsequent aspiration of air. Subcutaneous air on the operated side is not uncommon and it is a self-limiting phenomenon. Further chest cavity aspiration may minimize the extent of subcutaneous air. It is stressed that all needle or catheter aspiration should be performed with a meticulously sterile technique. The completion pneumonectomy patient differs in that there has already been a degree of mediastinal shift and so there is more stability.
Occasionally, deterioration of cardiorespiratory status secondary to acute mediastinal shift or a massive collection of fluid or blood, will require acute chest tube drainage to improve assessment of the etiology of the instability. In complicated or high-risk cases, a small indwelling 16F catheter with a 3-way stopcock can be left in the second or third intercostal space in the midclavicular line to allow easier subsequent aspiration of air or fluid. It is usually removed within 24 to 48 hours. However, this technique is rarely used. It should be stressed that the no-drainage technique requires extreme vigilance on the part of the staff, in the event that intervention is warranted.
Balanced Drainage
Initially described by Pecora and Cooper3 and advanced by Laforet and Boyd,4 as well as Miller and colleagues,5 balanced drainage allows continuous drainage while maintaining physiologic intrathoracic pressures. It also permits objective documentation of fluid or blood loss. This is especially important in complicated cases with increased bleeding or inflamed tissue planes. With this system, a more gradual shift of the mediastinum occurs (especially following a right pneumonectomy where the right hemidiaphragm rises more gradually). A 28F or 32F chest tube is placed posteriorly through the 8th or 9th interspace and directed superiorly. A second anterior tube may also be placed in the second or third interspace. Alternatively, a 16F catheter can be placed anteriorly in the second or third interspace in the midclavicular line to allow further intermittent air aspiration. A different system involves placing the lower chest tube into the waterseal with the chest tube clamped, and releasing it every hour for 5 minutes. Another system uses a high chest tube into the waterseal. Positive-pressure air is evacuated through the system. Fluid will not drain until the chest cavity fills up to the tube level. This allows more complete fluid drainage. Later, this system can be used as a closed irrigation system, if necessary, for infected space problems. It is important to note that the need for removal of air is the main indication for drainage, with reduction of fluid or blood accumulation as the secondary goal. In general, all chest tubes are removed within 24 to 48 hours unless a further irrigation plan is anticipated for a contaminated space.
The balanced-drainage system is illustrated in Figure 4A. The chest tube(s) are attached to a trap or collection bottle. The positive-pressure regulator bottle is a waterseal where pressure exceeding 1 cm H2O relative to atmos-pheric pressure is vented. The negative-pressure regulator is a reversed waterseal where negative pressure greater than 10 to 13 cm H2O relative to atmospheric pressure will cause an inflow of air. This results in a mean intra-pleural pressure of –5 cm H2O with fluctuations possible from +1 to –12 cm H2O. A commercial balanced-drainage unit is available (Figure 4B). However, with the positive-pressure release mechanisms on most commercial systems (Figure 4B), adjustments can be made to establish a balanced system (personal communication: Atrium Medical Corp., Hudson, New Hampshire, USA). The setup procedures include: (a) no suction employed; (b) the suction control chamber is not filled; (c) the waterseal is filled to the 1-cm level, as opposed to the usual 2-cm level, since the depth of this water determines the maximum amount of positive pressure in the chest. With a 1-cm waterseal, pleural negativity cannot exceed ap-proximately 17 cm H2O, as air at a less negative pressure will pass through the waterseal.
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Figure 4. Balanced-drainage system. (A) Conversion of a conventional 3-bottle system. (B) A commercial balanced-drainage system (Pleur-Evac A-4301 pneumonectomy unit; Deknatel Product Group, Tucker, GA, USA; adjusted commercial 3-bottle system).
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Continued Pneumothorax
Described by Kaunitz and Fisher6 in 1966, this system is not widely used. The hypothesis is that early excessive distension of the remaining lung is harmful. The goal is to maintain a midline mediastinum in the long term. All pleural fluid is aspirated on the 7th postoperative day. Air is injected into the spaces (+5 to +10 cm H2O). Subsequent injections are made to help maintain the mediastinum in the midline. This is performed at 4- to 8-week intervals. As pointed out in comments on Kaunitz and Fisher's paper, this has more merit in a right pneumonectomy where the diaphragm rises more slowly.6
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Discussion
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The purpose of a chest drainage system is to drain blood or other fluid and air from the chest cavity and restore the negative intrathoracic pressure following an open chest procedure. This can be accomplished by removing the air and fluid in a closed one-way system. This is the basis of the waterseal drainage system. The collapsed or remaining lung expands to fill the chest space. The subsequent rise of the hemidiaphragm and narrowed intercostal spaces, along with mediastinal shift, completes the process. The postpneumonectomy space is anatom-ically and physiologically altered. The immediate post-operative goal is to prevent acute mediastinal shifts that might cause cardiovascular collapse secondary to torsion of the right-sided systemic venous structures. This is especially true in the virgin state with a very mobile mediastinum. Additionally, accumulation of excessive blood or fluid may warrant monitoring, especially in a bloody or contaminated field. Excessive fluid with clotted blood may inhibit the remodeling process as well as predispose to infection and possible bronchial stump breakdown.
The postpneumonectomy space may be treated by continuous or intermittent drainage. However, routine drainage of this space is not mandatory. This space or cavity decreases with shifting of the mediastinum, narrowing of the ipsilateral intercostal spaces and elevation of the hemidiaphragm (Figure 5). A sterile serosanguineous effusion gradually clots and is infiltrated by fibroblasts. Decreased compliance of the contralateral lung may impede this obliteration process, yet eventually with hyperexpansion and a shift of the mediastinum, the space will decrease and in most cases, becomes obliterated. The process is initially completed within 4 to 6 weeks with opacification of the space on chest radiographs. It is complete in most cases by 12 weeks. Failure of progression of this process may reflect the presence of bronchopleural fistula, especially if the air and fluid levels fail to rise, fall, or become multiloculated. Complete absorption of all fluid is uncommon.
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Figure 5. Chest radiographs after left pneumonectomy for carcinoma. (A) In the immediate postoperative period, the trachea is at the midline and a nasogastric tube is in place. (B) One day postoperatively, there is evidence of subcutaneous air and increasing fluid in the empty chest space. (C) At 2 days postoperatively, a gradual movement of the mediastinum to the left, rising fluid level, and hyperexpansion of the right lung can be seen. (D) At 6 weeks postoperatively, there is deviation of trachea to the left, a shift of the mediastinum to the left, hyperexpansion of the right lung, elevation of the left hemidiaphragm, obliteration of the left chest space, and narrowing of the intercostal spaces.
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As stressed before, routine drainage of the post-pneumonectomy space is not necessary in the majority of cases. This eliminates the need for chest tube removal and avoids a potential source of pain, space contamination, infection, and accidental dislodgment of the chest tube. The patient is more mobile without a chest tube system. A shorter hospital stay is possible. However, attention to the clinical situation is warranted. Intrathoracic bleeding or early bronchial stump leak or dehiscence may go unrecognized. Routine or intermittent needle aspiration of air will usually suffice. Drainage should be considered in situations where attentive, experienced perioperative monitoring is not available. In the complicated bloody or infected postpneumonectomy space, drainage is recommended. Removal of infected or suspected fluid or excessive blood collection is desirable in such situations. This can be combined with irrigation of the infected postpneumonectomy space. With a right pneumonectomy, balanced drainage allows an even more gradual shift of the mediastinum. The extended pneumonectomy for mesothelioma with pericardial and diaphragmatic resection warrants drainage, as does the complicated completion pneumonectomy for cancer or infection. A post-neoadjuvant chemoradiation space may also justify drainage. Unfortunately, there are no early or long-term retrospective data to recommend any of these approaches. There are no recorded differences in infection or fistula formation between drained and undrained patients.
The fate of the postpneumonectomy space has been studied. Anderson and colleagues7 in 1968, documented complete cavity obliteration at approximately 9 months in postpneumonectomy cancer patients. All 127 patients had drainage for 24 hours postoperatively. Suarez and colleagues8 in 1969, found complete fluid absorption in only 10 of 37 patients dying at various intervals postoperatively. Varying degrees of fluid and air remained in the others. The type of drainage method had no influence on the long-term obliterative process.
It is clear that the mediastinum shifts to the operated side, the lung undergoes hyperexpansion and often herniates to the affected side, and the hemidiaphragm rises along with narrowing of the intercostal spaces. The method of early drainage does not influence this. Therefore, all efforts should be made to prevent the early deleterious effects of pneumonectomy, namely acute mediastinal shift, abnormal or excessive fluid or blood collection, infection, and bronchopleural fistula. After several days, the mediastinum becomes less mobile, and the space may be allowed to fill with proteinaceous fluid by removing the drainage system. The air-fluid level should gradually rise, and the fluid should clot, fibrose, and retract. An enlarging apical air space may indicate bronchial stump disruption that, if left untreated, can lead to an empyema.
In summary, a no-drainage policy suffices in the majority of cases, with the judicious use of needle aspiration of air. Selected use of drainage is indicated particularly in complicated, bloody, or infected spaces. In addition, a right-sided pneumonectomy, completion pneumonectomy, extrapleural pneumonectomy for inflammatory lung disease, pleural mesothelioma, or advanced lung cancer with increased dissection of tissue planes, combined pneumonectomy and thoracoplasty, and neoadjuvant chemoradiation therapy may require drainage and careful postoperative space management.
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Acknowledgments
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Special thanks to Jeff McGill, Craig Weimer, and Steve Vail at Atrium Medical Corporation, for technical assistance and preparation of figures.
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References
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Kaunitz VH, Fisher FC. Continued pneumothorax in the management of the postpneumonectomy pleural space: late results. Ann Thorac Surg 1966;2:455–63.[Medline]
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Anderson LJ, Egerdorf J, Stougard J. The pleural space succeeding pneumonectomy. Scan J Thorac Cardiovasc Surg 1968;2:70–3.[Medline]
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Suarez J, Clagett T, Brown AL Jr. The postpneumonectomy space: factors influencing its obliteration. J Thorac Cardiovasc Surg 1969;57:539–42.[Medline]
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Abstract
Introduction
