Chapter 25. Noninvasive Ventilation

Introduction

Noninvasive ventilation is a ventilatory technique in which a patient receives ventilatory assistance without the need for endotracheal intubation or a tracheostomy. While both negative and positive pressure ventilation are possible, the latter will be the focus of this chapter.

Definitions and Terms

• ▪  Noninvasive positive pressure ventilation (NPPV): Positive pressure ventilation delivered via nasal or full face mask using volume, pressure, bilevel positive airway pressure (BIPAP), or continuous positive pressure (CPAP) modes.
• ▪  CPAP: Positive pressure is applied through the mask at one pressure—CPAP is typically used for patient with upper airway obstruction to open collapsed airways.
• ▪  BIPAP: A ventilatory mode in which CPAP is supplied cycling between a higher and lower pressure at a regular rate—BIPAP is typically used to reduce the work of breathing and augment alveolar ventilation.
  • —Timed mode: Ventilator cycles regularly between high and low pressures and patient can breathe at each.
  • —Spontaneous mode (ie, pressure support): Patient inspiration triggers application of the higher pressure.
• ▪  Nasal mask: A mask applied over the nose, leaving the mouth uncovered—may be adequate for CPAP administration in diseases such as sleep apnea.
• ▪  Face mask: A mask applied over the nose and mouth—often preferred in acute respiratory failure, because most patients in this situation breathe primarily through the mouth.
• ▪  ARF: Acute respiratory failure.
• ▪  CHF: Congestive heart failure.

Techniques

• ▪  There are a variety of potential indications for the application of NPPV.
  • —Respiratory insufficiency in patients with COPD
  • —Respiratory insufficiency in patients with ARF
  • —Respiratory insufficiency following extubation
  • —Respiratory insufficiency with asthma
  • —Respiratory insufficiency in patient with CHF and pulmonary edema
  • —Respiratory insufficiency in patients with restrictive lung diseases and neuromuscular disorders
• ▪  There are a variety of contraindications to NPPV.
  • —Status post respiratory arrest
  • —Facial trauma
  • —Agitation, claustrophobia, lack of patient cooperation
  • —Excessive secretions
  • —High risk of regurgitation and aspiration
  • —Hemodynamic lability
  • —Decreased/impaired mental status
  • —Severe hypoxemia
• ▪  Patient preparation.
  • —Select appropriate mask (nasal vs. face) and size to patient.
  • —Secure mask to patient using circumferential straps around the head.
  • —Adjust for maximal patient comfort (Figure 25-1).
  • —Elevate head of bed to 45°.
  • —Selected ventilatory mode.
  • —Titrate ventilatory and oxygen support to achieve desired goals (Figure 25-2).
  • —Monitor respiratory rate, tidal volume, and pulse oximetry.
  Figure 25-1.Graphic Jump Location

  

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  Full face mask NPPV.

  Figure 25-2.Graphic Jump Location

  

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  BIPAP ventilator with inspiratory and expiratory settings.

Clinical Pearls and Pitfalls

• ▪  Skillful mask selection and fitting will maximize ventilatory support.
• ▪  Certain patients ...