Noninvasive Positive Pressure Ventilation in Acute Respiratory Failure

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Noninvasive Positive Pressure Ventilation in
Acute Respiratory Failure

• Paul Crawford, Maj, USAF, MC, FAAFP
• Eglin AFB Family Medicine Residency
• Eglin AFB, FL
• 29 Jan 2007

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NPPV is not just a bridge, it is a viable
treatment for respiratory failure

• Introduction/mechanism
• Patient selection
• Specific Clinical Scenarios
• Acute exacerbation of COPD
• Cardiogenic pulmonary edema
• Asthma
• Weaning off mechanical ventilation
• Immunocompromised patients
• Evidenced based conclusions

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Why do I need to know about NPPV?

• Reduce the need for intubation in Emergency Room
  and ICU setting

• Improve survival of our patients with respiratory
  failure

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Introduction

• Noninvasive positive pressure ventilation (NPPV)
  is the delivery of mechanically assisted or
  generated breaths without placement of artificial
  airway
• Both CPAP and BiPAP are considered NPPV
• Reduces mortality, length of hospital stay, and
  the need for mechanical ventilation

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Mechanism of benefit

• Improved alveolar ventilation
• Reduced work of breathing
• Rest of the respiratory musculature
• Increased intrathoracic pressure, decreases
  preload and afterload
• Why does it decrease mortality?
• Decreased hospital-acquired infections
• Decreased trauma from intubation
• Less complications of sedation

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Who should not be considered for NPPV?

• Contraindications
• Cardiac or respiratory arrest
• Nonrespiratory organ failure
• Hemodynamic instability
• Severe encephalopathy
• Severe UGI bleed
• Facial or neurosurgery, trauma
• Upper airway obstruction
• Inability to cooperate or protect airway
• High risk for aspiration

Too Sick
Cant protect airway
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Indicators for success

• Younger age
• Lower acuity of illness
• Able to cooperate
• Less air leaking
• Moderate hypercarbia (46-91 mm Hg)
• Moderate acidemia (pH 7.11-7.34)
• Improvements of gas exchange and vitals within 2
  hours

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How do I start NPPV?

• Monitored location, gt30 degree angle
• Select appropriate mask (Nasal or Oronasal)
• Select
• ventilator
• Apply headgear (1-2 fingers under strap)

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How do I start NPPV?

• Start with low pressure PSV or PAV (8-12/3-5)
• Example 10/4
• Gradually increase inspiratory pressure to
  alleviate dypnea, decrease respiratory rate
• Oxygen sat gt90
• Check for air leaks, Consider mild sedation
• Monitor blood gas at 1 hr

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When do I use NPPV?

• Specific scenarios supported by the evidence

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Acute exacerbation of COPD

• 74 yo M with known COPD presents with 5 days of
  worsening dyspnea. RR32, pulse oximetry 81.
  Alert, tripodding. Poor air movement.
• Treatment initiated with oxygen, nebs, steroids.
  ABG drawn.
• pH7.16, pO258, CO254, Bicarb34
• Treatment does not really helpwhat should you do?

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Respiratory Failure due to Acute Exacerbation of
COPD

• First line intervention as an adjunct to usual
  medical care. NPPV should be considered early in
  the course of respiratory failure.
• Decrease in mortality of 48
• RR.52, 95CI .35-.76
• Decrease of intubation by 59
• RR.41, 95CI .33-.53
• Decrease hospital length of stay 3.24 days
• 95CI -4.42 to -2.06
• Ram FSF, Picot J, Lightowler J, Wedzicha JA.
  Non-invasive positive pressure ventilation for
  treatment of respiratory failure due to
  exacerbations of chronic obstructive pulmonary
  disease. Cochrane Database of Systematic Reviews
  2004, Issue 3. Art. No. CD004104. DOI
  10.1002/14651858.CD004104.pub3.

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Cardiogenic pulmonary edema

• 63 yo F with known ischemic cardiomyopathy
  (EF30) presents with severe respiratory
  distress, cough, pulse ox83, RR36, afebrile,
  gasping, crackles on exam, JVD, 3 edema,
  BNP888
• pH7.32, pO246, CO254, Bicarb21
• Patient intubated. In ICU for 9 days, developed
  sepsis, died on day 12

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Cardiogenic pulmonary edema

• There are clear benefits in meta-analysis of
  randomized trials for CPAP
• risk of mortality 0.59
• 95CI 0.38-0.90
• risk of intubation 0.44
• 95CI 0.29-0.66
• Effective up to CPAP of 12.5
• Peter JV, Moran JL, Phillips-Hughes J, Graham P,
  Bersten AD. Effect of non-invasive positive
  pressure ventilation (NIPPV) on mortality in
  patients with acute cardiogenic pulmonary oedema
  a meta-analysis. Lancet 2006 367 11551163.
• Collins SP, Mielniczuk LM, Whittingham HA, et al.
  The use of noninvasive ventilation in emergency
  department patients with acute cardiogenic
  pulmonary edema A systematic review. Ann Emer
  Med. 2006 48260-269.

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Asthma

• No recommendation due to poor quality of evidence
• Ram FSF, Wellington SR, Rowe B, Wedzicha JA.
  Non-invasive positive pressure ventilation for
  treatment of respiratory failure due to severe
  acute exacerbations of asthma. Cochrane Database
  of Systematic Reviews 2005, Issue 3. Art. No.
  CD004360. DOI 10.1002/14651858.CD004360.pub3.

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Weaning strategy for intubated adults

• Possibly indicated in weaning patients with COPD
• Decrease in mortality of 59
• RR0.41 95CI 0.22-0.76
• Decrease ventilator assoc. pneumonia 72
• RR0.28 95CI 0.09-0.85
• Decrease hospital length of stay 7.33 days
• 95CI -14.05 to -0.61
• Burns KEA, Adhikari NKJ, Meade MO. Noninvasive
  positive pressure ventilation as a weaning
  strategy for intubated adults with respiratory
  failure. Cochrane Database of Systematic Reviews
  2003, Issue 4. Art.No. CD004127. DOI
  10.1002/14651858.CD004127.

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Immunosuppressed patients

• Apparent benefit of NPPV in immunosuppressed
  patients based on one randomized trial
• Hilbert G, Gruson D, Vargas F, et al. Noninvasive
  ventilation in immunosuppressed patients with
  pulmonary infiltrates, fever, and acute
  respiratory failure. NEJM 2001 Feb
  344(7)481-487.

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Special situations

• DNR
• Viable option to give patient and family time and
  comfort
• Emergency Room
• Pick the right patienthypercapnic COPD or CHF

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Conclusions from Level 1 Evidence

• Consider use in COPD, pulmonary edema,
  immunosuppressed states
• NPPV
• Decreases mortality
• Decreases need for intubation
• Decrease hospital stay
• If rapid improvement not seen, intubate

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NPPV is a very viable treatment for respiratory
failure due to

• Acute exacerbation of COPD
• Acute cardiogenic pulmonary edema
• Immunocompromised patients with pneumonitis