Bilevel positive airway pressure

The setup for BPAP using a mechanical ventilator

Bilevel positive airway pressure (BPAP), commonly referred to by the trademarked names BiPAP and BIPAP, is a form of non-invasive mechanical pressure support ventilation that uses a time-cycled or flow-cycled change between two different applied levels of positive airway pressure.^[1][2] It generates inspiratory (IPAP) and expiratory (EPAP) pressure gradients that complement the patient's own respiratory cycle, optimising the lungs' efficiency and reducing the work of breathing. BPAP has been shown to be an effective management tool for chronic obstructive pulmonary disease and acute and chronic respiratory failure.^[3]

BPAP should be distinguished from continuous positive airway pressure (CPAP), which applies a single level of positive airway pressure throughout the whole respiratory cycle and is used for different clinical conditions.

Use

Bilevel positive airway pressure is used when positive airway pressure is needed with the addition of pressure support. Common situations where positive airway pressure is indicated are those where taking a breath is difficult. These include pneumonia, chronic obstructive pulmonary disease, asthma and status asthmaticus.^[4][5]

Settings and measurements

• IPAP: this is the pressure applied during patient triggered breaths.
• EPAP: this is the pressure applied in between patient triggered breaths. It could also be considered a continuous positive pressure.
• FiO₂: The fraction of O₂ percentage that is being added to the delivered air.
• V_f: on many machines a respiratory rate is set as a guarantee for intermittent bursts of IPAP.

Terminology

The term "Bipap" can be confusing due to the existence of two almost identical terms being applied to two different modes:

• BIPAP The term "Biphasic/bilevel ventilation" was used to describe a mode of ventilation that alternates PEEP levels presented in 1988 by Professor Benzer of Innsbruck and his group. The term for this mode, as used by Draegar on their ventilators is "BIPAP" (note Uppercase "I").
• BiPAP is used by Respironics and others to denote their implementation of non-invasive pressure support plus CPAP (note lowercase "i").

References

1. C. Hormann, M. Baum, C. Putensen, N. J. Mutz & H. Benzer (January 1994). "Biphasic positive airway pressure (BIPAP)--a new mode of ventilatory support". European Journal of Anaesthesiology 11 (1): 37–42. PMID 8143712.
2. Guy W Soo Hoo, MD, MPH Clinical Professor of Medicine, University of California, Los Angeles, David Geffen School of Medicine; Director, Medical Intensive Care Unit, Pulmonary and Critical Care Section, West Los Angeles Healthcare Center, Veteran Affairs Greater Los Angeles Healthcare System; Oleh Wasyl Hnatiuk; Francisco Talavera (6 June 2011). "Noninvasive Ventilation". Archived from the original on 2010-06-07. Retrieved 7 June 2012.
3. M. A. Levitt (November 2001). "A prospective, randomized trial of BiPAP in severe acute congestive heart failure". American Journal of Emergency Medicine 21 (4): 363–369. doi:10.1016/s0736-4679(01)00385-7. PMID 11728761.
4. Williams AM, Abramo TJ, Shah MV, Miller RA, Burney-Jones C, Rooks S; et al. (2011). "Safety and clinical findings of BiPAP utilization in children 20 kg or less for asthma exacerbations.". Intensive Care Med 37 (8): 1338–43. doi:10.1007/s00134-011-2238-9. PMID 21567114.
5. Beers SL, Abramo TJ, Bracken A, Wiebe RA (2007). "Bilevel positive airway pressure in the treatment of status asthmaticus in pediatrics.". Am J Emerg Med 25 (1): 6–9. doi:10.1016/j.ajem.2006.07.001. PMID 17157675.