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Cuff Pressure Management(One essential part of VAP Management)

A vital task in intensive care is the monitoring of the cuff pressure of tracheostomy and endotracheal tubes during mechanical ventilation. To avoid complications it is mandatory to control the cuff pressure of all patients.

The two main functions of a cuff during ventilation:

  1. To ensure air tightness and therefore the efficiency of the ventilator support
  2. It protects the lower airway from the aspiration of infected oropharyngeal secretions

The two main functions of a cuff for spontaneously breathing patients who cannot control their own secretions:

  1. Reduced risk of aspiration and associated infection risk
  2. Protection from silent aspiration

A cuff pressure manometer should be used to measure the cuff pressure being exerted against the tracheal wall. The recommended limits to minimise damage to the trachea are 15-25 cmH2O (= 10-18 mmHg or 15-25 mbar), which is marked clearly on the dial of the manometer.

It is advised that the cuff pressure should be checked regularly with a hand manometer at least once per shift. Finger tip pressure on the external pilot balloon is NOT an accurate method of measuring the cuff pressure.

New publications stipulate that the cuff pressure should be checked every four hours!

Many articles and guidelines have been published all over the world with regards to cuff pressure management. In the following we are describing various problems related to incorrect cuff pressure management:

  1. Over Inflation
  2. Under Inflation
  3. When to Measure Cuff Pressure
  4. Cuff Pressure Measurement: Manometer
  5. The Need for Continuous Cuff Pressure Monitoring / Control Special topic: Cuff Pressure in the OR

A- Over Inflation

  • A pressure greater than 30 cmH2O for 15 minutes can result in tracheal mucosa damage
  • At 27 cmH2O blood flow can be reduced by 75% to the cuff site
  • Total obstruction of tracheal blood flow occurs at approx. 50 cmH2O
  • In patients with hypotension, pressures greater than 34 cmH2O may exceed the perfusion pressure in the trachea resulting in significant damage

B- Under Inflation

  • Micro aspiration has been shown to occur in cuff pressure of approx. 20 cmH2O
  • When cuff pressure below 20 cmH2O the risk of VAP is four times higher than if maintained between 20-30 cmH2O
  • Cuff pressure below 20 cmH2O will significantly affect the efficacy of subglottic tubes, as micro aspiration will occur

C- When to Measure Cuff Pressure

  • High Impact Intervention (2011) stipulate that cuff pressure should be monitored 4 hourly and at the set range of 20-30 cmH2O . Historically cuff monitoring by nurses on ICU has been poor, with a study showing 75% of ICU’s did not check cuff pressure

D- Cuff Pressure Measurement: Manometer

  • Widely used in
  • Manometer is (should be) connected at regular intervals
  • Results vary amongst practitioners
  • Pressure decreases by 2 cmH2O on connection, thereby dropping pressure may cause Micro aspiration

Warning: Palpation of Pilot Balloon is not sufficient

  • In study 70% incorrect measurement, either too high or low
  • No difference in experienced versus inexperienced practitioners
  • Cuff pressures noted at 100 cmH2O using this method

E– The Need for Continuous Cuff Pressure Monitoring / Control

  • Cuff pressure can change due to a number of :

– Positioning in bed, semi recumbent or supine

– Head position of patient, flexed

– Coughing / suctioning

– Level of sedation

– Length of intubation

  • Pressure within the cuff can change within the first hour of intubation
  • A study noted that pressure within the cuff decreased by 5 cmH2O within 4-5hours
  • Study showed low cuff pressure noted in 45% of manometer group versus0.7% in automated pressure group (8)

Special Topic: Cuff Pressure in the OR

  • Nitrous Oxide has been shown to increase cuff pressure intra-operatively by diffusing into the cuff
  • Pressures greater than 40 cmH2O have been reported in 91% of post op patients after nitrous oxide used and 45% of patients using other anaesthetics

About Zahra Eghbalpoor

Zahra Eghbalpoor
Managing Member, Board of Directors

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