How do I increase the ventilator's backup respiratory rate by 1–2 breaths per minute?

How to Increase the Backup Respiratory Rate by 1-2 Breaths Per Minute

Increase the backup rate setting on your ventilator by increments of 1-2 breaths per minute every 10 minutes until you achieve your desired ventilation goals. 1

Direct Adjustment Method

The American Academy of Sleep Medicine recommends that the backup rate (ST mode) or specified respiratory rate (timed mode) should be increased in increments of 1-2 breaths per minute. 1 This is a Level A consensus recommendation that applies to both non-invasive positive pressure ventilation (NPPV) and invasive mechanical ventilation settings.

When to Increase the Backup Rate

You should increase the backup rate in the following clinical scenarios:

• If the arterial PCO₂ remains 10 mm Hg or more above your target goal for 10 minutes or more despite optimizing pressure support settings 1

• If frequent and significant central apneas are present at baseline or during ventilation titration 1

• If the patient's spontaneous respiratory rate is inappropriately low to provide adequate minute ventilation 1

• If the patient fails to reliably trigger IPAP/EPAP cycles due to muscle weakness or inadequate respiratory drive 1

• If adequate ventilation or respiratory muscle rest is not achieved with maximum tolerated pressure support in spontaneous mode 1

Starting Point for Backup Rate

• Set the initial backup rate equal to or slightly less than the patient's spontaneous sleeping respiratory rate, with a minimum of 10 breaths per minute 1

• If the sleeping respiratory rate is unknown, use the spontaneous awake respiratory rate as your starting reference 1

Critical Adjustment Considerations

Timing of Adjustments

• Wait 10 minutes between each 1-2 breath per minute increment to allow adequate time to assess the physiological response 1

• Monitor transcutaneous or end-tidal PCO₂ continuously during adjustments to guide titration toward your ventilation goals 1

Inspiratory Time Coordination

When you increase the backup rate, you must simultaneously adjust the inspiratory time (IPAP time) to maintain appropriate inspiratory-to-expiratory (I:E) ratios. 1

• Maintain %IPAP time between 30-40% of the cycle time (cycle time = 60 seconds ÷ respiratory rate in breaths per minute) 1

• Use approximately 30% IPAP time for patients with obstructive airways disease to allow adequate exhalation time, especially at higher respiratory rates 1

• Use approximately 40% IPAP time for patients with restrictive disease such as chest wall disorders or decreased respiratory system compliance 1

• For example, at a respiratory rate of 15 breaths per minute, the inspiratory time should range from 1.2 to 1.6 seconds depending on the underlying pathology 1

Common Pitfalls to Avoid

• Do not assume that simply increasing respiratory rate will improve CO₂ clearance in all patients—a study of 14 patients with acute respiratory failure found that increasing respiratory rate from 15 to 30 breaths per minute did not significantly reduce PaCO₂ and actually increased alveolar deadspace and produced dynamic hyperinflation 2

• Do not increase the backup rate without monitoring for dynamic hyperinflation, particularly in patients with obstructive lung disease, as this can impair right ventricular function and reduce cardiac output 2

• Do not forget that increasing respiratory rate shortens the cycle time, which automatically reduces the maximum available inspiratory time for a given I:E ratio 1

• Recognize that higher respiratory rates may trigger increased spontaneous respiratory rate through mechanoreceptor feedback—one study demonstrated that increasing inspiratory flow rate (which shortens inspiratory time at a given tidal volume) increased spontaneous respiratory rate by 2.3 breaths per minute 3

Mode-Specific Guidance

For ST (Spontaneous-Timed) Mode

• The backup rate ensures a minimum respiratory rate by delivering machine-triggered breaths if the patient fails to initiate a breath within the time window determined by the backup rate 1

• If ST mode is not successful at meeting titration goals, switch to timed mode with a fixed respiratory rate 1

For Timed Mode

• Set the respiratory rate equal to or slightly less than the patient's spontaneous sleeping respiratory rate or the current backup rate if switching from ST mode 1

• All breaths are machine-triggered at the specified rate and inspiratory time in this mode 1

Monitoring Response to Adjustments

• Assess tidal volume delivery—if tidal volume remains low (<6-8 mL/kg) despite increasing backup rate, increase pressure support instead 1

• Monitor oxygen saturation—if SpO₂ remains below 90% for 5 minutes or more and tidal volume is low, increase pressure support rather than backup rate 1

• Evaluate patient-ventilator synchrony—adjust inspiratory time to maximize ventilation, synchrony, and patient comfort 1

• Check for excessive leak—mask or circuit leaks can undermine the effectiveness of any ventilator adjustment 1