Figure 3.1
Aeropleura
With these indications in mind, the treatment goal is to restore and control the subatmospheric pressure in the pleural space after evacuating air from the pleural space. Each drainage system connected to the chest drain (Bag, Heimlich-Valve, water seal, suction device) has to fulfill this task. The indication for insertion of a chest drain may be prophylactic in some cases i.e. when there is perhaps no air in the pleural space after lung or airway surgery. The chest drain is there to monitor and treat any potential air leaks during the postoperative course of the patient. Physiologically air will accumulate mainly in the apical and anterior parts of the chest cavity. One must consider though that there are anatomical variations to consider (adhesions from the chest wall to the lung, elevation of the diaphragm, and shift of intrathoracic organs) which may allow air to accumulate in other regions of the chest cavity or multiple locations. These aspects must be taken into account as well when evaluating the indication for placing a chest drain.
3.1.2 Evacuation of Fluids
There are many disease states and phenomena that may cause a pleural effusion (Fig. 3.2). The simple presence of fluid in the pleural space is not an indication for a chest drain. Indications for inserting a chest drain for fluid may be the amount of fluid, the need to monitor the amount and dynamics of fluid produced, the underlying disease, to assess the quality of the fluid, prophylaxis concerning secondary effects, therapeutic considerations, and pure palliative aspects.
Figure 3.2
Pleural effusion: typical localisation dorsobasal
Fluids compete for space in relation to the lung and its expansion as was described with gas as above. Draining the fluid gives the lung its ancestral place and volume back in the confines of the chest. If the fluid shows dynamic changes such as solidification, organization or infection, this can influence the timing of intervention.
Free floating fluid in the chest cavity will accumulate mainly in the basal and posterior areas. Anatomical changes such as pleural adhesions can lead to completely different localization of the fluid, i.e. divided in several compartments (apical localization or in the fissure). These considerations need to be addressed as well as the quality of the fluid as the effectiveness of the drain can be compromised.
Preformed or secondary developed cavities in the chest cavity such as a pleuro-pulmonary mismatch after previous lung resection will allow fluid to accumulate obligatorily without an indication for inserting a chest drain in such spaces.
In general, when assessing the indication for a chest drain for fluid removal, one must define whether a thoracentesis (single or multiple) has the same or even a better outcome then a chest drain for a determined time period.
3.1.3 Redirecting of Fluid
The below named reasons could lead to an indication for draining fluid not extra-thoracic but instead into another anatomic compartment (i.e. intraabdominal) (Fig. 3.3). A potential benefit is that the fluid is not lost but instead remains in the body. Long term extra thoracic drainage of fluid has the potential to lead to complications which could include malnutrition.
Figure 3.3
Thoraco-abdominal bypass
3.1.4 Pressure Relief
The accumulation of gas, air, or fluid may, under distinct circumstances, lead to the development of significant intrathoracic pressure that is detrimental to the respiratory and/or the cardiac systems (Fig. 3.4). This may necessitate emergent chest drainage. Taking into consideration the probability of recurrence and underlying disease dynamics, the indication in this setting may be thoracentesis versus insertion a chest drain for immediate relief.
Figure 3.4
Unphysiological intrathoracic pressure
3.1.5 Expanding Passive Atelectasis
Competition of fluid or gas/air with lung volume leads to the development of atelectasis by compression of the lung parenchyma (Fig. 3.5). There is a reduction of the vital capacity and eventually dyspnea may occur. Another consideration for inserting a chest drain is if the pleural fluid is rich in protein, fibrin, hemorrhagic, or is even pure blood. This leads quite quickly to the development of a rind covering the surface of the lung, followed by compression and atelectasis, resulting in a situation where even a sufficiently placed chest drain is no longer able to encourage lung reexpansion. Timing of chest drainage under these conditions is a very important issue as the success of the therapy is related to when the drain is placed during the clinical course.
Figure 3.5
Expansion of atelectasis
3.1.6 Application of Drugs Via the Drain
Chest drains may not only be used for relief or evacuation of air/gas/fluid but also to act as a route to allow potentially therapeutic medications to be instilled into the chest cavity (Fig. 3.6). The probability of reaching the target area in the chest cavity and the anticipated success rate have to be taken into consideration when considering such a procedure. Whether the instruments used for this are able to fulfil the task is another question.
Figure 3.6
Instillation of medications into the pleural space
3.2 Drainage of Air/Gas
3.2.1 Pneumothorax
3.2.1.1 Primary Spontaneous Pneumothorax
Chest drain insertion for primary spontaneous pneumothorax (PSP) can address several potential therapeutic goals such as management of an emergency situation, monitoring of a broncopleural fistula, and potential treatment of an underlying disease. The first goal is to evacuate the air from the pleural space that may be a consequence of a leak in the lung parenchyma allowing air to accumulate. At the same time, this should facilitate the more or less collapsed lung tissue to reexpand (Fig. 3.7) followed by restoration and maintenance of subatmospheric pressure in the pleura space.
Figure 3.7
Primary spontaneous pneumothorax without tension
In the setting of lung collapse with significant positive pressure within the chest, a tension pneumothorax can arise necessitating an emergent chest drain. In primary or spontaneous pneumothorax, per definition, the pleura and lung tissue are not diseased and therefore insertion of a chest drain can proceed in the usual fashion.
The necessity for chest drainage is in most cases given and depends on the quantitative occurrence of the pneumothorax and on the clinical symptoms (Klopp et al. 2007) [1].
The US-American (ACCP) an well as the British societies (BTS) offer guidelines for the treatment of primary spontaneous pneumothorax (Baumann et al. 2001; MacDuff et al. 2010), although both guidelines do not have the same results on all issues. One must recognize that there is only a small group of patients eligible for a purely conservative approach without thoracentesis or chest tube insertion (i.e. a “small” pneumothorax without any clinical symptoms). Even in this situation, the literature is not clear in its definition of what constitutes a “small” pneumothorax and differ concerning symptoms. The ACCP uses the distance from the apex of the lung to the upper end of the chest in its definition, whereas the BTS measures the distance from lung surface at the level of the hilum to the chest wall. In summary, only the “small” asymptomatic pneumothorax with less than 1 cm distance between lung and chest wall can be treated without procedural intervention.
In all other clinical settings the air should be evacuated. This can be done by thoracentsis with needle aspiration (Devanand et al. 2004) or by inserting a small bore catheter placed with a hollow-bore needle. Due to a low success rate this procedure is not recommended in infants (Soccorso et al. 2015). Needle aspiration is also not able to monitor any potential ongoing parenchymal leak. Small bore catheters are able to evacuate air (Vedam and Barnes 2003) but these catheters tend to clog quite fast because of fibrin so that ongoing safe function is not guaranteed. This is one of the reasons that frequently a 20 F catheter is therefore used.
If there is clinical concern for the presence of an on-going air leak, a large bore catheter (20–32 F) should be chosen. With these larger bore catheters, higher flow rates can be managed so that the occurrence of subcutaneous emphysema is less frequent. One must remember though that in an acute life threatening tension pneumothorax, simple needle aspiration can provide initial pressure relief as to allow the subsequent chest drain insertion to be done in a more controlled fashion.
The insertion of a chest drain for spontaneous pneumothorax should restore the physiological conditions in the pleural space. The chest tube remains for a defined period of time working as a monitoring tool and may possibly be the only therapeutic procedure needed. Exact rules for post procedural therapeutic course are not consistent (ACCP and BTS). In the end existing risk factors and other patient specific parameters must be taken into account when making an individualized therapeutic decision.
There are very few situations where a drain placement for primary spontaneous pneumothorax is not indicated.
3.2.1.2 Secondary Pneumothorax
There are numerous disease states that may cause a secondary pneumothorax (SPX). Pathological changes in the lung parenchyma such as what is seen in chronic obstructive pulmonary disease or interstitial lung disease (Ichinose 2015) are underlying factors. When a chest tube is indicated in the setting of a spontaneous pneumothorax, the clinician must be aware that therapy can be significantly complicated by severe changes in lung parenchyma (i.e. giant bullae) or abnormalities of the pleural space (i.e. pleural adhesions) Fig. 3.8.
Figure 3.8
Pneumothorax and giant bulla
In some cases parenchymal changes such as a giant bulla can be misinterpreted as a pneumothorax (Fig. 3.9). Such an abnormality is not an indication for chest tube insertion and iatrogenic complications can arise such as organ perforation.
Figure 3.9
Simulated pneumothorax in case of giant bulla
Pneumothoraces in the setting of interstitial lung disease and cystic fibrosis are associated with high rates of complications and even mortality (Flume et al. 2010). Sufficient drainage has to be established quickly. Needle aspiration has been shown to be an inferior procedure in these patients.
In the case of a SPX there is almost always an indication to insert a chest drain as was described previously. If there is a significant risk of an air leak, a drain larger than 20 F is indicated in most cases. In the setting of an insufficiently drained pneumothorax (drain in the fissure, covered by lung tissue, on-going large air leak, etc.), the patient must be quickly reassessed for possible insertion of a second tube or if the previous tube should be replaced with a single new tube.
Patients with a secondary pneumothorax may have changes in the pleural cavity (postoperative, post inflammatory, etc.) which can cause difficulties during chest drain insertion. This may lead to complications and subsequent harm. Giant bullous emphysema must also be taken into consideration!
3.2.2 Iatrogenic Pneumothorax
The proportion of iatrogenic pneumothoraces in all patients suffering from a pneumothorax is quite high. The main indication for chest tube insertion is to drain air from the pleural space and restore physiological conditions. Some patients may be able to be closely observed without needle aspiration or having a chest tube insertion inserted for management of an iatrogenic pneumothorax.
The patients suffering from iatrogenic pneumothoraces are heterogeneous. There are essentially two groups of patients with these pneumothoraces and should be separately considered when deciding on chest drainage. The first group have pneumothoraces that are related to biopsies and line insertions (Despars et al. 1994). “Small” asymptomatic pneumothoraces may be observed and treated without further invasive action in this group. All other instances in this group should be treated by needle aspiration or with insertion of a small bore catheter. If there is a large air leak present, this is an indication for insertion a larger bore catheter.
The second group of patients incur iatrogenic pneumothoraces from barotrauma from mechanical ventilation or are ventilated at the time of the first appearance of the (iatrogenic) pneumothorax. In these situations the risk of getting a tension pneumothorax is very high and therefore chest drain insertion is indicated. A small bore catheter in these circumstances is correlated with low success rate, and therefore the use of large bore (>20 F) is recommended.
Every pneumothorax in patients requiring mechanical ventilation must be drained!
3.2.3 Traumatic Pneumothorax
Traumatic pneumothoraces are not always due to a penetrating injury. It is important to note that more than 30 % of traumatic pneumothoraces are not detectable on conventional x-ray but only are identified with a CT scan (Yadav et al. 2010). When this occurs it is referred to as an “occult pneumothorax”.
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