There is a potential space between the parietal and visceral pleura which surround the lungs. In a normal healthy adult this space contains nothing other than some secretions to help the two membranes slide against each other. However there can be instances when the space between these two membranes can fill with air or a gas. As the space fills with this air or gas so the patient’s breathing may start to become compromised.
Damage to the chest wall can be caused by physical trauma or as a complication of medical or surgical interventions or underlying disease. This can then allow the passage of a gas or air into the pleural space creating a pneumothorax.
A pneumothorax which occurs in the absence of any other significant lung disease and without an apparent cause is known as a primary pneumothorax, whilst that which occurs in the presence of existing lung disease is known as a secondary pneumothorax.
The size of the pneumothorax can vary and this, and the consequent effect it is having upon the patient, will determine what treatment the patient will receive.
Small spontaneous pneumothoraces will often only require monitoring and will resolve without intervention. However with the larger pneumothorax or where the patient is experiencing symptoms as a result, a chest drain may need to be placed to allow the air in the pleural space to escape and the lung to reinflate.
Occasionally the pneumothorax can become very significant very quickly and cause the patient serious problems. When the pneumothorax becomes large enough it can start to push some of the major organs within the chest to one side. Obviously one of the most important organs in the chest is the heart and as this is pushed over it can begin to compromise its function, causing the patient serious problems. When this occurs this is known as a tension pneumothorax and urgent intervention is required. This can initially be managed by inserting a large bore cannula in the chest wall on the affected side to allow some of the air to escape. However, ultimately the patient urgently needs the placement of a chest drain.
It may also be that rather than just gas or air there may be blood within the pleural space, caused by for example trauma. When this occurs this is known as a heamo-pneumothorax, and requires a similar management to the above.
Pleural Effusion and Empyema.
A pleural effusion is the collection of fluid within the pleural cavity through a number of mechanisms.
Transudative effusions are essentially caused by problems with the circulation which allows fluid to cross the membranes and into the pleural cavity. This kind of effusion is managed by treating the underlying medical disorder. Occasionally a chest drain will be inserted to manage the sometimes severe respiratory symptoms that the patient may experience. However, in this case, the chest drain will not stop the fluid from continuing to build up but will only take it away. Other actions need to be taken to improve the patients circulatory disorder which is causing the buildup of fluid in the first place. It is often of concern to the practitioner that once the chest drain is removed the fluid will build up in the pleural space once more. This becomes especially difficult in the patient with some underlying chronic conditions.
Exudative effusions can be caused by conditions such as pneumonia, malignancy and tuberculosis.
Pleural effusions are common in patients with pneumonia and whilst antibiotics will often treat the pneumonia, well they can go on to develop what are called parapneumonic effusions. Again if the patient becomes symptomatic as a result of this effusion a chest drain may need to be inserted to drain some of the fluid away. This type of effusion can also rapidly coagulate and form a fibrous characteristic which will require surgical intervention to remove.
Those patients with a malignancy who developed a pleural effusion have a poor prognosis. However they can have some symptom relief by the insertion of a chest drain to help drain some of the fluid away allowing them to breathe more easily. The chest drain therefore is not a curative procedure but rather a palliative one.
The presence of pus within the pleural cavity, usually in the context of the pneumonia, is also known as a pleural empyema. The insertion of a chest drain may help these patients, however a reasonable proportion of them may require surgical drainage because of inadequate drainage due to clogging of the chest tube.
Insertion of Tube.
After the decision has been taken to insert the chest tube the patient should be first consented. This should be an informed consent, describing the process to them and the possible complications which could result.
Aseptic technique should be maintained at all times, washing of hands, wearing of gloves, gown and full antiseptic preparation for the insertion site.
The favoured patient position is for them to be sat at approximately 45° in the supine position with their arm raised up behind their head on the affected side in order to make the axillary area accessible. It may be that the patient requires some assistance to hold their arm in this position and this could be provided by the nurse assisting with the process.
Insertion of a chest drain is a painful procedure and it is therefore very important that the patient receives sufficient local anaesthetic to the insertion site. This should also then be allowed sufficient time to take effect before the procedure begins. It may also be that some other form of analgesic could be considered to be given either before or after the procedure.
The chest drain can come in a range of sizes from 10 to 36Ch. These can be inserted either via an open surgical incision or using the Seldinger technique which you will be familiar with from the insertion of the central line. The Seldinger technique incorporates a guide wire through a needle followed by a dilator system.
The smaller chest drain is generally favoured these days as it is better tolerated and associated with less discomfort. It may be that a larger chest drain is required if there is blood or pus in the pleural cavity. In the past the chest drain kit came with a sharp trocar, which was a short metal spike used to go through the chest wall. Its use is now discouraged except in the most experienced hands as it is too easy to cause damage to the other structures within the chest using this implement.
In most circumstances the tube will be placed in the fifth intercostal space in the mid-axillary line. This is considered to be within the safe triangle for placement of the tube.
A small cut will be made in the skin layer and then a needle will be inserted, which is attached to a syringe. This will be inserted slowly aspirating on the syringe all the time until fluid or air is aspirated into the syringe. This confirms that the needle is in the pleural cavity. Once the needle is in the pleural cavity the guide wire is then inserted through the needle. The needle is then removed and the dilator is used to stretch the skin and the muscle layer between the ribs.
Once this is done the small bore chest tube can be inserted over the wire. Once the practitioner is satisfied with the placement the guide wire can be removed and the chest drain bottle tubing can be attached.
Care and Management
The chest drain bottle forms an underwater seal drainage system. The drainage tube is submerged to a depth of 2 cm in the water of the collection chamber. This underwater seal creates a one-way valve through which air is expelled from the pleural space and prevented from re-entering during the next inspiration.
The chest drainage tube should be sutured to the patient’s skin at the entry site. This guards against the risk of the tube falling out and also provides a degree of comfort for the patient as the tube will not slide in and out through the skin.
It is vitally important that the chest drain is kept below the level of the patient at all times otherwise fluid will siphon back into the patient’s chest wall.
It is not necessary to place large quantities of dressings around the chest drain insertion site. These may restrict chest wall movement and cause increased moisture collection around the site which may lead to wound breakdown. The dressing should allow inspection of the wound site and drain connections should not be covered.
After the chest drain has been inserted regular observations should take place which should include breath sounds and equality of chest movements as well as respiratory rate pattern and depth.
The fluid level in the chest drain bottle should also be monitored. Decisions about the patient’s future management may be affected by the amount of the fluid drained from the pleural cavity. If the drainage were to stop suddenly this should also be highlighted as it may be that the tube has become blocked with blood or pus and this would need to be remedied fairly quickly.
With the drainage of a pleural effusion it is important that this process is a slow one as if it occurs to quickly there is a possibility of re-expansion pulmonary oedema. There is not much evidence for how quickly one should drain a pleural effusion but there are suggestions that you should not drain more than 1500 mls at any one time
Suction may sometimes be applied to the drainage bottle to facilitate drainage of a pleural effusion or following thoracic surgery. A high volume/low pressure system should be used with 5 kPa of suction being applied. You should not apply a high pressure system to a chest drain as this can cause serious complications.
Clamping of chest drains should only be done very cautiously and a chest drain which is bubbling should never be clamped. The bubbling indicates that air is moving from the alveoli and into the pleural space. If the tube is clamped in this case the air in the pleural space has nowhere else to go and consequently the pneumothorax can develop very quickly. This can then lead to a tension pneumothorax with the high complications this can cause.
Removal of Chest Drain
Chest drains are usually removed when the drainage is less than 100 to 150 mls over 24 hours or breath sounds have returned to normal and bubbling has ceased. A chest x-ray will confirm that the underlying problem has been resolved.
This procedure will require two people, one to remove the drain and the other to tie the sutures to close the wound. It is important therefore, before starting the procedure, to ensure that the sutures will be able to close the wound after the drain has been removed.
When removing the drain one should ask the patient to hold their breath and bear down. This increases the intrathoracic pressure and will help to reduce the risk of a recurrent pneumothorax.
As soon as the chest drain has been removed the other nurse then ties the sutures to close the wound and provide an airtight seal. A chest x-ray then needs to be repeated to ensure that the pneumothorax has not recurred.