Measurement of endotracheal tube cuff pressure

Endotracheal tube cuff should be inflated continuously and deflated during intubation, extubation and repositioning. Tracheostomy tube cuff also inflated continuously in patients on CPAP or mechanical ventilation support. Tracheostomy patients who are breathing spontaneously may have the cuff inflated continuously ( In the patient with altered conscious level without ability to protect the airway.), deflated continuously or inflated only for feeding if the patient is at risk of aspiration.

TYPES OF EQUIPMENT NEEDED

• Suction source/machine
• Suction catheter
• Tonsil suction
• Syringe 10-mL
• AMBU bag with O2 support
• Pressure manometer (aneroid or mercury)

Nursing procedure

• Explain the procedure to the patient.
• Reduce the patient's anxiety and improve co-operation.
• Use face shield.
• Spraying of secretions may occur.
• Suction the trachea, oral and nasal pharynx
• Take out secretions collected above the cuff, which could be aspirated into the lungs during the cuff is deflated. Never reuse the trachea with the same catheter used for suctioning the mouth. 
• Slowly deflate the cuff.
• The test balloon at the tip of the tubing remains inflated as long as the cuff at the distal end of the tube is inflated. A vacuum within the syringe is sensed when no more air can be aspirated.
• Spontaneous patient cough or manually inflate the lungs with an AMBU bag. Ready to collect secretions in a gauze pad or use tonsile suction.
• Positive pressure in the airway may help secretion upside and avoid aspiration of secretions.
• Suction tracheostomy or ET tube.
• Secretions may present above the inflated cuff and around the exterior tube have now speeded downward. Coughing reflex may be stimulated, a chance to mobilize secretions.
• Provide proper ventilation while the cuff is deflated. The patient requires assisted ventilation, provides manual AMBU bag support and otherwise provides oxygen support.
• Assess the patient closely for tolerance. Failure of tidal volume or PEEP may promote hypoxemia and hypocarbia. Cuff should not be deflated for more than 30 to 45 seconds.
• Inflate cuff no leak technique-: Connect the air-filled syringe to the cuff injection port, then gently push air until no air leakage from the patient's lungs around the cuff. Mention the amount of air pushed to provide a seal.
• Air leakage will be heard when the intra-airway pressure is most positive ( maximum peak airway pressure). During spontaneous breathing, air leakage will be heard on exhalation. If the patient has positive pressure ventilation, air leakage can be heard at maximum ventilator inspiration.
• Minimal leak technique for mechanical ventilator patient-: Connect the air-filled syringe to the cuff injection port, then gently push air until no leak is heard at maximum peak airway pressure. Mention the amount of air injected.
• Inflate the cuff lowest possible pressure while still maintaining an adequate seal. Avoid tracheal necrosis from excessive or continuous cuff pressure. Modification in the VT setting may be necessary to compensate for the leak.

Analysis the minimal occluding volume 

• Push adequate air into the manometer tubing to raise the dial reading 1 cm H2O above the zero reading.
• This " pressurizes" the tubing and avoid loss of air from the cuff to the tubing when the reading is taken.
• Insert male port of 3-way stopcock into the cuff injection port. One female port of stopcock holds the air-filled syringe' and one port holds the pressure manometer.
• Push air into until desired intracuff pressure is reached at maximum peak airway pressure.
• Aneroid manometer calculate cuff pressure in cm H2O: A pressure of 20-25 cm H2O is appropriate. Mercury manometer pressure should be 15-20 mm Hg. Pressure more than upper limit may affect tracheal vessels' compression, resulting in lower blood flow to tissue. Pressure less than lower limit may cause aspiration of gastric or oral secretions.
• Monitor amount of air wants to reach the desired intracuff pressure.
• Take out the stopcock from the injection port.
• Almost all injection port have self-sealing valves. If not a cap or closed stopcock may be left in the injection port.
• While cuff is inflated, check cuff pressure every four hours. Keep cuff pressure between 20 and 25 mm Hg or 25 and 35 cm H2O
• Pressure is more than the normal limit, resulting in tracheal necrosis. Insufficient cuff pressure may allow aspiration.
• Note the amount of air required to maintain cuff pressure at this level.
• Establishes a baseline for evaluation of change in pressure.

Inability to maintain a seal

• check the degree of leakage and length of time elapsed since cuff volume was replenished.
• If an inflated cuff leaks air within 10 minutes, analysis is needed. Possibilities may be:
• Cuff site is above the vocal cords.
• Incompetence of self-sealing valve on injection port.
• Tracheal dilation ( may need larger size tube)
• Cuff may be ruptured, requiring a new tube
• If leakage recurs, place three-way stopcock between syringe and injection port, inflate cuff, close stopcock. Remove syringe ( and manometer, if used) leaving closed stopcock in injection port.
• The closed stopcock in the injection port acts as "plug" if the self-sealing valve is incompetent.
• If air leak continues, tube replacement or repositioning may be needed.