Ensure that patient and health care provider safety standards are met during this procedure including:

  • Risk assessment and appropriate PPE
  • 4 Moments of Hand Hygiene
  • Procedural Safety Pause is performed
  • Two patient identification
  • Safe patient handling practices
  • Biomedical waste disposal policies


  1. Monitor Respiratory System
  2. Monitor SpO2
  3. Communicate Findings
  4. Monitor Blood Gases
  5. Provide Emergency Equipment
  6. Maintain Positioning
  7. Suction as Required
  8. Change Chest Tube Dressings
  9. Assess Chest Drainage Systems
  10. Prepare for Emergency Response/Chest Tube Safety
  11. Document



Monitor Respiratory System

Breath sounds are assessed at the start of each shift and prn. Respiratory rate, rhythm and effort is monitored continuously for all ventilated patients. RNs in CCTC assess the patients rate, minute volume, airway pressures and ventilator settings q1h and prn, and document findings in the graphic record. RNs in CCTC provide continuous respiratory monitoring and report significant findings to the Respiratory Therapist and the physician.


Monitor SpO2

All CCTC patients have continuous SpO2 monitoring, unless otherwise ordered. When digits are used for monitoring, monitoring sites are rotated and the skin integrity assessed q2h.

SpO2 may be inaccurate in the presence of nail polish, carbon monoxide (e.g., smoke inhalation) or impaired peripheral perfusion. Blood gases provide more accurate assessment of oxygenation in these situations.

SpO2 alarms are on at all times. If alarms are disabled, the reason is documented in the AI record.

The RN is responsible for continuous monitoring and for communicating relevant findings to the appropriate member of the health care team. The respiratory therapist is responsible for the set-up and adjustment of the ventilator.


Communicate Findings

Ongoing communication between the RN and RRT responsible for the care of a patient is required. Planned changes for sedation, weaning and overall goals of care are discussed in advance and communicated upon completion.

Many factors influence a patient's ventilation requirements including hemodynamic stability, acute brain injury, procedural or operating room plans and level of sedation. Interventions must be made with a full knowledge of the treatment plan and of the patient's condition. RNs in CCTC and RRTs must work as a team to ensure optimal ventilatory support.


Monitor Blood Gases

All patients require daily blood gas evaluation unless otherwise ordered. Frequency reductions are indicated for stable, long-stay patients.

Blood gases are repeated within one hour of a ventilator change for acute admissions or unstable patients and to evaluate respiratory status following spontaneous breathing trials.

If changes are made to the FiO2 or PEEP to correct a low PaO2, gases do not need to be repeated if the SpO2 demonstrates an appropriate response. SpO2 may not be reliable in the presence of carbon monoxide or poor peripheral circulation.

When patients are switched from full ventilation to PS mode, blood gas evaluation is not required if the patient remains comfortable, RR is WNL, and the minute volume remains unchanged. Repeat gases If signs of respiratory distress develops.

PRN blood gases are repeated for evidence of respiratory distress, to evaluate or monitor acid-base disturbances (e.g., increased or low bicarbonate on electrolyte panel, elevated lactate, renal or hepatic failure, DKA), to assess hemodynamic instability or identify causes for new arrhythmias. Documentation in the AI record.

When obtaining a blood sample for analysis on the Point of Care technology, all samples must have a patient identication label on the syringe before leaving the bedside.


Provide Emergency Equipment

Each bedside will have a manual resuscitation bag connected to oxygen and a ventilation mask. If PEEP > 5, PEEP is added to the resuscitation bag.

An intubation box is kept in each Bay.


Maintain Positioning

All intubated patients will be nursed with the head of bed elevated > 30 degrees unless contraindicated. The bed position will be documented in degrees in the graphic record each hour. If the HOB is not elevated > 30 degrees, the rationale is documented in the AI record.


Suction as Required

Appropriate PPE is required when suctioning please refer to:

LHSC interprofessional suctioning guidelines.

LHSC Hand Hygiene Policy

LHSC Routine Practices Policy

LHSC Donning and Doffing Policy

Suctioning is done prn. Patients on neuromuscular blocking agents or who are paralyzed are suctioned twice per shift and prn with an assisted cough technique. A closed-system in-line technique is used.

Suctioning catheters are rinsed with sterile saline following each suctioning episode.

Suctioning efforts are documented in the graphic record. Findings not WNL are documented in AI record.

Suctioning is only done when indicated to reduce unnecessary airway trauma and patient discomfort. Patients with paralyzed diaphragms are more difficult to assess and often have secretions not detected audibly due to impaired cough. Assisted cough technique facilitates clearance in the absence of a cough.


Change Chest Tube Dressings

Chest tube dressings are changed q 2 days and prn. Ensure appropriate PPE is utilized when performing chest tube dressings (hand hygiene and non-sterile gloves).

LHSC Hand Hygiene Policy

LHSC Routine Practices Policy

LHSC Donning and Doffing Policy

Dressing changes are documented in the graphic record. Findings not WNL are documented in AI record.


Assess Chest Drainage Systems

At the start of each shift assess each chest tube for the following and document in the 12 hour AI Record (Figure 1):


  1. Presence/adequacy of underwater seal (assess with suction off; should always be at 2 cm) Figure 2
  2. Presence of fluctuation in the water seal (assessed with suction off) Figure 3
  3. Presence of an air leak; rate on a scale of 0-7/7 Figure 3
  4. Adequacy of suction
  5. Presence of bottle of water (see below)
  6. Ensure that a bottle of water is availalbe for each tube (see #10)




Figure 1.01:  CCTC AI Assessment Record


Maintenance of the underwater seal is the most important component of a chest drainage system.

The undewater seal chamber is divided into 7 vertical columns to provide a semi-quantitative assessment of the amount of leak. Identify the highest number where air bubbles are detected to determine the severity of the leak and document out of 7. For example, a leak of 1/7 (bubbles only in the first column) is very small.  A leak of 4-5/7 or higher is a significant leak.

The presence of a leak indicates that air is being drawn through the system.  It does not differentiate air from a pneumothorax versus system leak.

Fluctuation indicates that the chest tube is likely in the pleural space and patent, and able to detect the changing pressures during breathing. When a tube is not fluctuating, it suggests that the tube is either outside the pleural space, the tube is occluded, or the lung has rexpanded and the pneumothorax is resolved.

When a pneumothorax resolves, reexpansion of the lung will compess the drainage holes and prevent the detection of the pleural space presssure changes. 

When the air leak is gone and the undewater seal stops fluctuating, patient should be reassessed for readiness to remove chest tube.

Figure 1.02: Confirm underwater seal
Figure 1.03: Assess fluctuations
1.04: Record air leak
Figure 1.05: Confirm suction level

Prepare for Emergency/Chest Tube Safety

Clamping of chest tubes should be avoided (except for momentarily while changing chest drainage units).  This is particularly among patients who have an air leak or active bleeding as clamping can precipitate a tension hemo/pneumothorax and increase the risk for clotting of the tube.

If a chest tube becomes disconnected, immediately submerge the chest tube into a bottle of water with the connection port located at least 2 cm below the meniscus.  A level of 2-5 cm is likely safe in most patients.

Always ensure there is water in the underwater seal. This is the most important step before connecting a chest drainage unit. This is good practice even when using a unit with an undewater seal valve.

Maintain a bottle of sterile water at the bedside at all times.  Ensure that a bottle of water accompanies the patient during any transit.


Small Bottles of Water

Small 59 ml bottles (Figure 6) are available for this use from the cart in Bay 3 with the chest drainage supplies. Keep one for each tube at the bedside. It can be taped to the chest drainage unit. Check at the start of each shift to ensure a bottle of water is available.

Small bottles can be used to create a quick underwater seal.  Always ensure that the tube is a MINIMUM of 2 cm below the level of the water meniscus (Figure 7). Insert the chest tube halfway into the mini bottle.  This will provide a temporary undewater seal of ~4 cm H220 (Figure 8 ). Insertion halfway is easier to maintain than a more superficial level and should still enable air evacuation if the patient has a significant leak.

Tape or hold the tube into position so that it doesn't flip out of the water. If the tube is taped into position, ensure that there is adequate room for venting of air around the bottle neck.

This temporary measure will prevent air from reentering the chest. Be aware that the deeper the tube is inserted, the more difficult it will be for air to be evacuate air.  Deep insertion will function the same as clamping the tube.  Monitor closely for respiratory distress, particularly if the patient had a previous air leak.

Figure 1.06: Small bottles for emergency underwater seal

Large Bottles of Water

It is harder to visualize the depth of the tube within the larger bottles, therefore adjusting the water level and inserting the tube to the bottom of the bottle provides easier depth assessment.  Dump approximately half of the water out of the bottle (to 250 ml level) (Figure 9).  This will provide a 5 cm water level if the chest tube is inserted all the way to the bottom (Figure 10).

If the level of water is less than 2 cm of water, the "air seal" is inadequate and can allow air to enter the pleural space, creating a larger pneumothorax. If the level of water is too high (greater than 2 cm of water), it becomes harder for air to be evacuated. This can mimic clamping.

When a chest tube becomes disconnected, air can quickly be drawn into the pleural space. Clamping will prevent evacuation of the air and can create the environment for a tension pneumothorax.

Any sudden disconnection, particularly among a patient with an existing air leak or receiving mechanical ventilation is at the greatest risk of tension pneumothorax during clamping.

The volume of water, presence of fluctuations and degree of air leak is best assessed with the suction temporarily stopped.

Risk of Deep Submersion

In the event that a chest tube becomes disconnected in a patient with a signficant air leak or pneumothorax, monitor the depth of the chest tube closely until a new unit can be set-up.  An air leak should continue to be visible in the water bottle; if it is not, withdraw the tube until a leak resumes (ensuring a minimum depth of 2 cm H20 is maintained at all times). 

MRI Compatibility

The small bottles have a metal capFor patients traveling to MRI who have chest tubes, take a standard 500 ml regular bottle of sterile water.

Changing Chest Drainage Units

Temporarily clamp the chest tube (with 2 kelly clamps) when changing the chest drainage collection unit.  In patients with a persistent air leak this should be done as quickly as possible.

Internal link to LHSC Chest Drainage Protocol

Figure 1.07: Depth of water in 59 ml bottle of water
Figure 1.08: Depth of water at 4 inches 59 ml bottle of water
Large Water
Figure 1.09: 5 inches of water in 500 ml bottle of water after dumping half the volume.
Large bottle with tube
Figure 1.10: Submersion into half filled 500 ml bottle provides a water seal of 5 cmH20

Document Output

Keep the chest drainage unit in an upright position to avoid transfer of drainage between columns..

Chest drainage is assessed hourly and output volume and color is documented in the AI record. When chest drainage output stabilizes and remains less than 10 ml per hour, frequency can be reduced to Q 4 - 12 hours as appropriate.



Figure 11:  Single drainage collecting unit with 4 graduated fluid collection columns.


When drainage has filled incompletely as shown above, the unit can be tipped to move fluid from one chamber to another to align the volume correctly. 

Chest drainage fluid drains into vertical cannisters.  The right hand cannister fills first, then spills over to fill the next cannister toward the left.  If the drainage unit is maintained in a perfecly upright position, the graduated markings will accurately reflect the true output.

Because the drainage unit will invariably be tilted, the columns rarely fill to the top before spillage toward the left hand cannister occurs. For this reason, the sum of each column must be added to measure true output.


Last Update: 
February 2, 2020
Brenda Morgan, CNS, CCTC


  1. LHSC Nursing Practice Manual Internal link to LHSC Chest Drainage Protocol
  2. Zsis, C. et al. (2015). Chest drainage units in use. Ann Transl Med;3(3):43