Noninvasive Ventilation

General

• Definition: Use of positive pressure ventilation without invasive airway (i.e. endotracheal tube or tracheostomy)

• Avoids risks and complications associated with endotracheal intubation and mechanical ventilation (trauma to airway with laryngoscopy, sedation/analgesia and neuromuscular blockade, ventilator associated pneumonia, patient discomfort and loss of verbal communication) 

• Benefits: Can reduce work of breathing, redistribute alveolar water, improve VQ matching, minimize airway collapse, preserve spontaneous respiration

• Patient selection and proper mask/interface fit is crucial

When should Noninvasive Ventilation be Used?

• Not absolutely clear but in general:

  • After extubation as a form of support

  • Pulmonary edema expected to improve

  • Obstructive sleep apnea

  • Neuromuscular disorders

  • Postoperative patients 

  • Asthmatic patients with hyeprcabia

  • Cystic Fibrosis exacerbation

When should Noninvasive Ventilation Generally be Avoided?

• • Cardiac/respiratory arrest

  • Nonrespiratory organ failure

  • Severe encephalopathy (i.e. GCS <10)

  • Severe UGI bleeding

  • Hemodynamic instability or unstable arrhythmia

  • Facial surgery, trauma, or deformity

  • Inability to cooperate or protect airway

  • High risk for aspiration

  • Toxin Ingestion

  • Foreign body aspiration

  • Mediastinal Mass

  • Not improving within first few hours of noninvasive positive pressure ventilation (NIPPV)

Practical Considerations

• Interface: nasal vs. full face vs. RAM cannula (used in neonates/infants)

• Pressure necrosis at nasal bridge: can try duoderm and alternate interfaces or time off to mitigate risk

• Gastric distension/aspiration: NGT to suction

• Difficulty with secretions: Breaks off NIPPV

• Tolerance: Sedation is rarely needed (dexmedetomidine is a reasonable drug to use if need be). Can try manual application of gentle CPAP at low pressures with Mapelson mask to first get patient accustomed to PPV

• HFNC: 

  • In a multicenter randomized trial of infants <12 months of age with bronchiolitis treated outside of an ICU, those who received high flow nasal cannula at 2 L/kg/min (avg weight ~ 7.3-7.6 kg) had significant less treatment failure than those who were started on regular nasal cannula at 2L/min. 61% of those that failed nasal cannula responded to HFNC (Franklin et al, NEJM 2018)

  • CPAP (4-8) or HFNC of 4-8LPM to reduce work of breathing (flow rates of 2L/kg/min seem to be associated with delivered PEEP). 

• Ventilatory modes: 

  • CPAP: Continuous Positive Airway Pressure

  • PCV: Pressure control ventilation (similar to pressure control on an invasive ventilator with set rate)

  • PSV: Pressure support ventilation (no set rate, pressure support given to patient initiated breaths)

  • AVAPS: Average Volume Assured Pressure Support (Similar to PRVC on a mechanical ventilator, uses algorithm to continually estimate pressure needed to deliver the set tidal volume)

• Type of Ventilator:

  • Standard ICU ventilator (i.e. Avea)

  • BiPAP device (i.e. Respironics Vision or Trilogy)

  • Laptop ventilator (LTV)

• Settings: 

  • High-Low approach: Start around 20-25 cm H2O for PIP and 5-8 for PEEP and wean as tolerated

  • Low-High approach: Start at 8-10 cm H2O for PIP and 3-5 for PEEP and uptitrate as needed

• Do not delay endotracheal intubation if patients are not improving quickly on NIPPV as this can lead to worsened patient condition and unfavorable conditions for intubation. Frequent assessment of whether the patient is improving is critical. 

What is the Evidence for NIPPV?

• Adults:

  • Effective for acute cardiogenic pulmonary edema (Lin, Chest 1995)

  • Decreased intubation rates, hospital mortality in patients with COPD and hypoxemic respiratory failure (Plant, Lancet 2000 and Ferrer, Am Jnl Resp Care 2003)

  • Effective for weaning off mechanical ventilation (Nava, Ann Int Med 1998)

• Pediatrics:

  • Primarily associative retrospective data so difficult to draw causative conclusions (i.e. those that do well on NIPPV may simply be "less sick") but:

    • Associated with lower mortality (Demoule, Intensive Care Med 2006)

    • Decreased incidence of nosocomial infection (Girou, JAMA 2000)

    • Decreased frequency of invasive mechanical ventilation in patients with acute respiratory failure (Peter, CCM 2002)

    • Lower clinical asthma scores and respiratory rates (Thill, PCCM 2004 and Basnet, PCCM 2011)

    • Improved HR, RR, P/F ratios and lower ETI rates (Fortenberry, Chest 1995 and Yanez, PCCM 2008)

    • Decreased hospital ICU stays and sleep related respiratory values in neuromuscular disease (Katz, Arch Dis Child 2004)

• When does NIPPV fail?

  • When patient does not demonstrate signs of improvement within first 1 hr. For example, in 42 pediatric patients with acute respiratory failure, FIO2 >80% after 1 hour of NIPPV was associated with the need for ETI (sensitivity 56%, specificity 83%, Negative predictive value 71%) (Bernet, PCCM 2005) 

References

1) M. Ferrer, A. Esquinas, M. Leon, et al.: Noninvasive ventilation in severe hypoxemic respiratory failure: a randomized clinical trial. Am J Respir Crit Care Med.168:1438-1444 2003

2) T. Honrubia, F. Garcia Lopez, N. Franco, et al.:Noninvasive vs conventional mechanical ventilation for acute respiratory failure. Chest. 128:3916-3924 2005

3) M. Antonelli, G. Conti, M.L. Moro, et al.: Predictors of failures of noninvasive positive pressure ventilation in patients with acute hypoxemic respiratory failure: a multicenter study. Intensive Care Med. 27:1718-1728 2001

4) J. Bott, M.P. Carroll, J.H. Conway, et al.: Randomized controlled trial of nasal ventilation in acute ventilatory failure due to chronic obstructive airways disease.Lancet. 341:1555-1557 1993

5) M.M. Fernandez, A. Villagra, L. Blanch, et al.:Noninvasive mechanical ventilation in status asthmaticus. Intensive Care Med. 27:486-492 2001

6) M. Antonelli, G. Conti, M. Bufi, et al.: Noninvasive ventilation for treatment of acute respiratory failure in patients undergoing solid organ transplantation. A randomized trial. JAMA. 283:235-241 2000

7) M. Ferrer, A. Esquinas, M. Leon: Noninvasive ventilation in severe hypoxemic respiratory failure: a randomized clinical trial. Am J Respir Crit Care Med.168:1438-1444 2003

8) . Esteban, F. Frutos-Vivar, N.D. Ferguson Noninvasivepositive pressure ventilation for respiratory failure after extubation, N Engl J Med. 350 2004 2462–2460

9) L.J. Yan, M. Yunge, M. Emilfork, et al.: A prospective, randomized, controlled trial of noninvasive ventilation in pediatric acute respiratory failure. Pediatr Crit Care Med.9:484-489 2008

10) P.J. Thill, J.K. McGuire, H.P. Baden, et al.: Noninvasivepositive-pressure ventilation in children with lower airway obstruction. Pediatr Crit Care Med. 5:337-3422004