Two Ventilating Strategies in One Mode

The Puritan Bennett™ Bi-Level software option provides two strategies for enabling patients to breathe spontaneously at both upper and lower positive airway pressure levels, helping to improve synchrony.

  • APRV helps support the current goals for most ARDS patients while optimizing spontaneous breathing.
  • Bi-Level ventilation in conventional TH:TL ratio simplifies the transition from controlled spontaneous breathing, without requiring any change of mode.

The Bi-Level software option has been shown to be associated with a reduction of opioid use by 40% in critically ill cancer patients under mechanical ventilator support.([FOOTNOTE=Saul J et al. The effect of Bi-Level ventilation on opioid utilization in a medical intensive care unit. Resp Care. 2000;45(8):1013.],[ANCHOR=],[LINK=])



Puritan Bennett™ Bi-Level software mode offers distinct enhancements over pressure support and pressure control, particularly in spontaneously breathing patients:

  • Synchronized transitions between PEEP levels with patient breathing([FOOTNOTE=Puritan Bennett™ 800 Series Ventilator System Operator’s and Technical Reference Manual.],[ANCHOR=],[LINK=])
  • Augmentation of all spontaneous breathing at high and low PEEP levels with at least 1.5 cmH2O of support
  • Monitoring of spirometry for all spontaneous breaths at high and low PEEP levels

Additionally, Bi-Level mode offers expanded Pressure Support (PS) capabilities. When the time at lower PEEP is set long enough to allow spontaneous breathing, PS can be used. If the PS level is set high enough, the breaths at the upper PEEP can also be pressure-supported.

Clinical advantages

The clinical advantages of spontaneous breathing at two PEEP levels include:

  • A decrease in sedation

If the patient is allowed to breathe spontaneously during all phases of support, and transition between pressure levels is synchronized, sedation due to patient/ventilator dysynchrony may be kept at a lower level.([FOOTNOTE=Lefebvre DL, Stock C. Airway pressure release ventilation. The Department of Anesthesiology, Emory University School of Medicine, Atlanta, Georgia.],[ANCHOR=],[LINK=]),([FOOTNOTE=Müller E. Clinical application of novel ventilation techniques. Int J Artif Organs. 1995;18(10):656-669. ],[ANCHOR=View Abstract],[LINK=/content/covidien/websites/medtronic/com/en/covidien/support/clinical-evidence.html?id=882301]),([FOOTNOTE=Burchardi H, Rathgeber J, Sydow M. The concept of analgo-sedation depends on the concept of mechanical ventilation.Yearbook of Intensive Care and Emergency Medicine. 1995. Berlin.],[ANCHOR=],[LINK=]),([FOOTNOTE=Sydow M, Burchardi H, Ephraim E, Zielmann S, Crozier TA. Long-term effects of two different ventilatory modes on oxygenation in acute lung injury. Comparison of airway pressure release ventilation and volume-controlled inverse ratio ventilation. Am J Respir Crit Care Med. 1994;149(6):1550-1556. ],[ANCHOR=View Abstract],[LINK=/content/covidien/websites/medtronic/com/en/covidien/support/clinical-evidence.html?id=882299]),([FOOTNOTE=Stock MC. Conceptual basis for inverse ratio and airway pressure release ventilation. Seminars in Respiratory Medicine. July 1993;14(4):270-274.],[ANCHOR=],[LINK=])

  • Improved patient monitoring

Bi-Level mode provides enhanced monitoring information that can assist with clinical decisions. It monitors mandatory and spontaneous tidal volumes and minute volume separately, which offers the clinician a clear understanding of how the patient’s spontaneous ventilation contributes to total ventilation.

  • Simplicity and ease of use

Bi-Level software combines two strategies in one mode. By allowing the principles of APRV to easily transition from controlled ventilation to all levels of augmented ventilation, Bi-Level mode may be an appropriate tool for clinicians to manage a patient for the entire course of a patient’s disease process.([FOOTNOTE=Hörmann C, Baum M, Putensen C, Mutz NJ, Benzer H. Biphasic positive airway pressure (BIPAP)--a new mode of ventilatory support. Eur J Anaesthesiol. 1994;11(1):37-42. ],[ANCHOR=View Abstract],[LINK=/content/covidien/websites/medtronic/com/en/covidien/support/clinical-evidence.html?id=882302]),([FOOTNOTE=Müller E. Clinical application of novel ventilation techniques. Int J Artif Organs. 1995;18(10):656-669.],[ANCHOR=View Abstract],[LINK=/content/covidien/websites/medtronic/com/en/covidien/support/clinical-evidence.html?id=882301])



Low Pressure (PL)

Range: 0 to 45 cmH2O.
Resolution: PEEPL from 0 to 20 cmH2O: 0.5 cmH2O.
  PEEPL from 21 to 45 cmH2O: 1 cmH2O.
  PEEPL must be at least 5 cmH2O less than PEEPH.

High Pressure (PH)

Range: 5 to 90 cmH2O.
Resolution: 1 cmH2O for all levels of PEEPH.
  PEEPH must be at least 5 cmH2O greater than PEEPL, and at least
  2 cmH2O less than the ↑PCIRC limit.

Low PEEP time (TL)

Range: ≥ 0.2 second.
Resolution: 0.01 second.

High PEEP time (TH)

Range: ≥ 0.2 to 30 seconds.
Resolution: 0.01 second.

Ratio of PH to PL time (TH:TL)

Range: 1:299 - 149:1
Resolution: 1 for TH:TL ratios ≥ 100:1 and ≤ 1:100.
  0.1 for TH:TL ratios from < 99.9:1 to 10.0:1 and 1:10.0 to > 1:99.9.
  0.01 for TH:TL ratios from < 9.99:1 to > 1:9.99.