Noninvasive Positive Pressure Ventilation
I Noninvasive Positive Pressure Ventilation
A Many have considered acute respiratory failure caused by the following as situations in which NPPV should be applied (Box 43-1).
1. Chronic obstructive pulmonary disease (COPD), acute exacerbation
2. Cardiogenic pulmonary edema
4. Neurologic/neuromuscular disease
5. Weaning from ventilatory support
1. Multiple randomized controlled trials of the use of NPPV in patients with COPD have indicated improved outcome.
2. Patients with a moderate to severe acute exacerbation of COPD and treated with NPPV
a. Are less likely to be intubated
b. Are less likely to develop nosocomial pneumonia
c. Have a shorter mechanical ventilation time
d. Have a shorter intensive care unit (ICU) stay
3. NPPV is a “standard of care” to manage an acute exacerbation of COPD.
4. NPPV for COPD should be the first-line therapy in all institutions caring for these patients.
1. NPPV has been useful for patients with cardiogenic pulmonary edema who are unable to effectively ventilate (Paco2, >45 cm H2O).
2. Patients with only hypoxemic acute respiratory failure should be treated with 8 to 12 cm H2O continuous positive airway pressure (CPAP).
3. Patients with a myocardial infarction or suspected myocardial infarction should not receive NPPV or CPAP; they should be intubated and invasively ventilated.
4. During NPPV 100% oxygen should initially be delivered when the indication is cardiogenic pulmonary edema.
1. Patients with severe asthma have a difficult time tolerating a tight-fitting mask.
2. These patients tend to be claustrophobic.
3. Case studies from a few centers have indicated success with NPPV for patients with asthma.
4. However, most do not recommend NPPV or CPAP for acute severe asthma.
5. Heliox does work well for many patients with acute severe asthma to reduce work of breathing (see Chapter 34).
E Neurologic/neuromuscular disease
1. NPPV works well for these patients when applied for short-term or long-term use for those with progressively deteriorating diseases.
2. No randomized controlled trials have been performed, but dozens of case series demonstrate improved gas exchange and avoidance of intubation.
3. NPPV should always be considered for patients with neurologic/neuromuscular disease before a decision to intubate is made.
F Weaning from ventilatory support
1. A series of randomized controlled trials have evaluated elective extubation to NPPV for patients who have failed to respond to weaning trials.
2. However, other randomized controlled trials have shown no benefit from elective extubation.
3. Extubation to NPPV should be considered for patients who have failed to respond to multiple attempts at weaning but all clinical signs indicate they should be weaned.
4. Patients who are extubated after passing a weaning trial but subsequently develop respiratory failure should also be considered for NPPV; however, existing data seem to indicate NPPV does not prevent reintubation.
1. Mask CPAP has been used over the years to manage acute hypoxemic respiratory failure from ALI.
2. A number of groups have used NPPV with varying success to manage hypoxemic respiratory failure.
3. However, the NPPV failure rate has been high in these patients (>60%), and mortality of those failing NPPV has also been high (>60%).
4. It is frequent that either CPAP or NPPV is maintained too long, delaying the decision to intubate.
5. As a result during intubation an increased risk of cardiac arrest exists.
6. NPPV or CPAP should be cautiously applied to patients with ALI, and if a beneficial response is not observed in a few hours, intubation should not be delayed.
1. These patients almost always develop nosocomial pneumonia if intubated and have a high mortality when intubated.
2. As a result NPPV should always be considered first-line therapy to manage ventilatory failure.
3. Randomized controlled trials indicate a decrease in intubation rate and mortality if NPPV is used.
I Patients awaiting lung transplantation
1. Many of these patients benefit from the short-term and long-term use of NPPV.
2. Intubation in transplantation candidates, similar to immunosuppressed patients, frequently results in the development of nosocomial pneumonia.
1. NPPV has been used to provide relief of hypercarbic and hypoxemic respiratory failure and to provide palliative care for these patients.
2. Because NPPV is life support patients should fully understand what it is they are receiving before it is started.
3. NPPV is useful for these patients to
4. The expected outcome of NPPV in this setting is different from that in any of the other settings in which NPPV is applied.
A Successful application of NPPV requires different skills than the successful application of invasive ventilation.
B The therapist must fully understand the indications, benefits, and limitations of NPPV.
C Patients must be part of the process. They must fully understand what is to be done and must be cooperative if the application is to be successful.
D The initial application period can be time consuming. Frequently 60 to 90 minutes of a therapist’s time is required during initial application.
E After appropriate patient instruction a mask is selected (see Section V, The Mask).
1. Initial application ideally is by the patient holding the mask to his or her face.
2. If the patient is incapable of holding the mask, the therapist should hold the mask.
3. Do not strap the mask to the patient’s face until he or she is completely accepting of the mask and all questions of the patient have been answered.
