Are E sens (expiratory sensitivity) and I sens (inspiratory sensitivity) expressed on a scale from 1-6?

Ventilator E-Sens and I-Sens Settings Scale

E-sens (expiratory sensitivity) and I-sens (inspiratory sensitivity) are not expressed on a scale from 1-6, but rather use different measurement units depending on the ventilator mode and manufacturer.

Understanding Ventilator Sensitivity Settings

I-Sens (Inspiratory Sensitivity)

• I-sens is typically measured in:
  • Flow trigger: L/min (liters per minute)
  • Pressure trigger: cmH₂O (centimeters of water)
• The American Thoracic Society recommends adjusting I-sens to avoid auto-triggering while minimizing work of breathing 1
• Lower numerical values indicate higher sensitivity (less patient effort needed)
• Higher numerical values indicate lower sensitivity (more patient effort needed)

E-Sens (Expiratory Sensitivity)

• E-sens is typically expressed as a percentage (%) of peak inspiratory flow
• Common settings range from 25-40% of peak flow 1
• Controls the transition from inspiration to expiration
• Lower percentages (25-30%) are recommended for patients with obstructive disease 2
• Higher percentages (35-40%) are recommended for patients with restrictive disease 2

Clinical Implications and Settings

For I-Sens:

• Starting with a default setting and adjusting based on patient response is recommended 1
• If auto-triggering occurs: decrease sensitivity (increase numerical value)
• If increased work of breathing: increase sensitivity (decrease numerical value)

For E-Sens:

• The ERS/ATS Task Force on Standards recommends starting with E-sens at approximately 25-30% of peak inspiratory flow 2, 1
• For patients with obstructive airways disease: use shorter inspiratory time (approximately 30% IPAP time) to allow adequate expiration time 2
• For patients with restrictive disease: use longer inspiratory time (approximately 40% IPAP time) 2

Practical Application

• When setting up non-invasive positive pressure ventilation (NPPV), the inspiratory time is calculated based on respiratory rate and I:E ratio 2
• The relationship between respiratory rate, cycle time, and inspiratory/expiratory time follows specific formulas:
  • Cycle time = 60 / respiratory rate
  • Inspiratory time = %IPAP time × cycle time
  • I:E ratio = inspiratory time / expiratory time 2

Common Pitfalls to Avoid

• Mistaking sensitivity settings for a universal 1-6 scale
• Not accounting for different ventilator manufacturers using different units and scales
• Setting I-sens too sensitive, causing auto-triggering from cardiac oscillations or circuit leaks
• Setting I-sens too insensitive, increasing patient work of breathing
• Not adjusting E-sens based on underlying pathophysiology (obstructive vs. restrictive disease)

The proper adjustment of these settings is essential for optimizing patient comfort, reducing work of breathing, and improving ventilation outcomes 1.