Chapter 21 Chest Drainage Pg. 524-528
Chest drainage is a crucial intervention for improving gas exchange and breathing in postoperative period
and in the cases on pneumothorax, hemothorax and pleural effusion. Chest tubes and drainage system are
used to re-expand the lung by removing fluid, blood and air. Normal breathing operates on a principle of
negative pressure. Air and fluid collected in pleurae space restricts lung expansion and reduces gas
exchange. So, for example: opening in the chest like in surgery causes air to rush in making the vacuum in
the pleural cavity escape. Remember there is a negative pressure between the pleural cavity called
intrathoracic pressure that needs to be maintained to facilitate breathing movements. Since normal
negative pressure or vacuum is no longer there, lungs may partially or fully collapse since they depend on
vacuum to stay fully expanded. Parietal pleura lines inside chest wall. Visceral pleura lines the surface of
each lung. In between those is the pleural cavity normally filled with thin fluid (20ml or less). Pleural
effusion is a buildup of fluid between the tissues (pleural cavity) that line the lungs and the chest.
Pneumothorax is the collapse of the lung resulting form air filling the pleural cavity. Hemothorax is
the collection of blood in the pleural cavity.
Chest tubes may be inserted to drain fluid or air from any of the three compartments of the thorax (the
right and left pleural spaces and the mediastinum. The mediastinal space is an extrapleural space that
lies between the right and left thoracic cavities and contains the large blood vessels, heart, mainstem
bronchus, and thymus gland. If fluid accumulates here, the heart can become compressed and stop
beating, causing death. Mediastinal chest tubes can be inserted either anteriorly or posteriorly to the heart
to drain blood after surgery. Chest drainage systems have a suction source, a collection
chamber for pleural drainage, and a mechanism to prevent air from reentering the chest
with inhalation. Chest drainage systems come with either wet (water seal) or dry suction control. In
wet suction systems, the amount of suction is determined by the amount of water instilled in the suction
chamber. The amount of bubbling in the suction chamber indicates the strength of the suction. Wet
systems use a water seal to prevent air from moving back into the chest on inspiration. Dry systems use a
one-way valve and may have a suction control dial in place of the water.
Water seal system
The traditional water seal system (or wet suction) for chest drainage has three chambers: a collection
chamber, a water seal chamber, and a wet suction control chamber. The collection chamber acts as a
reservoir for fluid draining from the chest tube. Suction may be added to create negative pressure and
promote drainage of fluid and removal of air. The suction control chamber regulates the amount of
negative pressure applied to the chest. The amount of suction is determined by the water level. It is
usually set at 20 cm H2O; adding more fluid results in more suction. After the suction is turned on,
bubbling appears in the suction chamber. A positive-pressure valve is located at the top of the suction
chamber that automatically opens with increases in positive pressure within the system. Air is
automatically released through a positive-pressure relief valve if the suction tubing is inadvertently
clamped or kinked.
The water seal chamber has a one-way valve or water seal that prevents air from moving back into the
chest when the patient inhales. There is an increase in the water level with inspiration and a return to the
baseline level during exhalation; this is referred to as tidaling. Intermittent bubbling in the water seal
chamber is normal, but continuous bubbling can indicate an air leak. Bubbling and tidaling do not
occur when the tube is placed in the mediastinal space; however, fluid may pulsate with the
patient’s heartbeat. The water level in the water seal chamber reflects the negative pressure present in the
intrathoracic cavity. A rise in the water level indicates negative pressure in the pleural or mediastinal
space.
, Dry suction seal system
Dry suction water seal systems (dry suction) have a collection chamber for drainage, a water seal
chamber, and a dry suction control chamber. The water seal chamber is filled with water to the 2-cm level.
Bubbling in this area can indicate an air leak. The dry suction control chamber contains a regulator dial
that conveniently regulates vacuum to the chest drain. Water is not needed for suction in these systems.
Without the bubbling in the suction chamber, the machine is quieter. However, if the container is knocked
over, the water seal may be lost.
Once the tube is connected to the suction source, the regulator dial allows the desired level of
suction to be set; the suction is increased until an indicator appears. The indicator has the same
function as the bubbling in the traditional water seal system—that is, it indicates that the vacuum is
adequate to maintain the desired level of suction. Some drainage systems use a bellows (a chamber that
can be expanded or contracted) or an orange-colored float device as an indicator of when the suction
control regulator is set.
When the water in the water seal rises above the 2-cm level, intrathoracic pressure increases. Dry suction
water seal systems have a manual high-negativity vent located on top of the drain. The manual high-
negativity vent is pressed until the indicator appears (either a float device or bellows) and the water level
in the water seal returns to the desired level, indicating that the intrathoracic pressure is decreased.
Chest drainage is a crucial intervention for improving gas exchange and breathing in postoperative period
and in the cases on pneumothorax, hemothorax and pleural effusion. Chest tubes and drainage system are
used to re-expand the lung by removing fluid, blood and air. Normal breathing operates on a principle of
negative pressure. Air and fluid collected in pleurae space restricts lung expansion and reduces gas
exchange. So, for example: opening in the chest like in surgery causes air to rush in making the vacuum in
the pleural cavity escape. Remember there is a negative pressure between the pleural cavity called
intrathoracic pressure that needs to be maintained to facilitate breathing movements. Since normal
negative pressure or vacuum is no longer there, lungs may partially or fully collapse since they depend on
vacuum to stay fully expanded. Parietal pleura lines inside chest wall. Visceral pleura lines the surface of
each lung. In between those is the pleural cavity normally filled with thin fluid (20ml or less). Pleural
effusion is a buildup of fluid between the tissues (pleural cavity) that line the lungs and the chest.
Pneumothorax is the collapse of the lung resulting form air filling the pleural cavity. Hemothorax is
the collection of blood in the pleural cavity.
Chest tubes may be inserted to drain fluid or air from any of the three compartments of the thorax (the
right and left pleural spaces and the mediastinum. The mediastinal space is an extrapleural space that
lies between the right and left thoracic cavities and contains the large blood vessels, heart, mainstem
bronchus, and thymus gland. If fluid accumulates here, the heart can become compressed and stop
beating, causing death. Mediastinal chest tubes can be inserted either anteriorly or posteriorly to the heart
to drain blood after surgery. Chest drainage systems have a suction source, a collection
chamber for pleural drainage, and a mechanism to prevent air from reentering the chest
with inhalation. Chest drainage systems come with either wet (water seal) or dry suction control. In
wet suction systems, the amount of suction is determined by the amount of water instilled in the suction
chamber. The amount of bubbling in the suction chamber indicates the strength of the suction. Wet
systems use a water seal to prevent air from moving back into the chest on inspiration. Dry systems use a
one-way valve and may have a suction control dial in place of the water.
Water seal system
The traditional water seal system (or wet suction) for chest drainage has three chambers: a collection
chamber, a water seal chamber, and a wet suction control chamber. The collection chamber acts as a
reservoir for fluid draining from the chest tube. Suction may be added to create negative pressure and
promote drainage of fluid and removal of air. The suction control chamber regulates the amount of
negative pressure applied to the chest. The amount of suction is determined by the water level. It is
usually set at 20 cm H2O; adding more fluid results in more suction. After the suction is turned on,
bubbling appears in the suction chamber. A positive-pressure valve is located at the top of the suction
chamber that automatically opens with increases in positive pressure within the system. Air is
automatically released through a positive-pressure relief valve if the suction tubing is inadvertently
clamped or kinked.
The water seal chamber has a one-way valve or water seal that prevents air from moving back into the
chest when the patient inhales. There is an increase in the water level with inspiration and a return to the
baseline level during exhalation; this is referred to as tidaling. Intermittent bubbling in the water seal
chamber is normal, but continuous bubbling can indicate an air leak. Bubbling and tidaling do not
occur when the tube is placed in the mediastinal space; however, fluid may pulsate with the
patient’s heartbeat. The water level in the water seal chamber reflects the negative pressure present in the
intrathoracic cavity. A rise in the water level indicates negative pressure in the pleural or mediastinal
space.
, Dry suction seal system
Dry suction water seal systems (dry suction) have a collection chamber for drainage, a water seal
chamber, and a dry suction control chamber. The water seal chamber is filled with water to the 2-cm level.
Bubbling in this area can indicate an air leak. The dry suction control chamber contains a regulator dial
that conveniently regulates vacuum to the chest drain. Water is not needed for suction in these systems.
Without the bubbling in the suction chamber, the machine is quieter. However, if the container is knocked
over, the water seal may be lost.
Once the tube is connected to the suction source, the regulator dial allows the desired level of
suction to be set; the suction is increased until an indicator appears. The indicator has the same
function as the bubbling in the traditional water seal system—that is, it indicates that the vacuum is
adequate to maintain the desired level of suction. Some drainage systems use a bellows (a chamber that
can be expanded or contracted) or an orange-colored float device as an indicator of when the suction
control regulator is set.
When the water in the water seal rises above the 2-cm level, intrathoracic pressure increases. Dry suction
water seal systems have a manual high-negativity vent located on top of the drain. The manual high-
negativity vent is pressed until the indicator appears (either a float device or bellows) and the water level
in the water seal returns to the desired level, indicating that the intrathoracic pressure is decreased.
