Volume Expansion Tx Concluded

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Volume Expansion Tx Concluded

• By Jim Clarke

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CPAP

• Continuous Positive Airway Pressure
• A simple approach which maintains some positive
  pressure in the airway at the end of exhalation
• Net effect of CPAP is that FRC is increased
• There is a high correlation between improvement
  of atelectasis and the patient having a higher
  than normal FRC

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Review of Lung Volumes Capacities
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Beneficial Effects of CPAP

• Recruitment of collapsed alveoli
• The work of breathing is decreased as lung
  compliance (stretchability) improves
• Improvement of gas distribution
• Improvement in secretion removal

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Indications for Use of CPAP

• Tx of post-operative atelectasis
• Should be used continuously
• Has been used in the treatment of cardiogenic
  pulmonary edema

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Contraindications to CPAP

• If blood pressure is very low
• Diastolic of lt50 mm Hg
• If patient has one or more of the following
• facial trauma (cannot use mask CPAP)
• nausea
• untreated pneumothorax
• elevated intracranial pressure (ICP)

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Hazards of the Use of CPAP

• Barotrauma (pneumothorax)
• Gastric distension
• Air-trapping
• Decrease in BP
• Can be very uncomfortable to the face of patient
  using mask CPAP

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Example of a Mask CPAP Setup
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What Does CPAP Accomplish?

• Increases the FRC by increasing the amount of air
  in the chest at the end of exhalation
• The net effect of increasing FRC is to
• Re-open any atelectatic areas
• Improve any hypoxemia that may be resulting from
  the atelectasis
• CPAP is also used to treat Sleep Apnea secondary
  to upper airway obstruction

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End of Section on CPAP