Triggering Rise Time E Sens

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  • 25 25 25 25 25 Once the patient has triggered the ventilator into inspiration, the next concern regarding patient comfort and coordination between the ventilator and the patient is flow acceleration percent.
  • 30 30 30 30 30 Next we will talk about preventing pressure overshoot and and sustaining the breath as it relates to the active exhalation valve.
  • 33 33 33 33 33 In the spontaneously breathing patient in PS the next issue is transition into exhalation.
  • 26
  • 34 34 34 34 34 18 Most ventilators currently on the market today terminate the inspiratory phase in Pressure Support Ventilation (PS) according to set termination criteria. This criteria is usually a percent of the peak flow for that particular breath. Clinicians have been limited in the past due to the inability to adjust this termination criteria. Expiratory Sensitivity (ESENS) defines the percentage of the projected peak inspiratory flow (VMAX) at which the ventilator terminates flow and thus cycles from inspiration to expiration during spontaneous breathing. A fixed PS termination criterion may potentially result in several clinical issues. If inspiratory flow terminates too early, it can lead to a decreased tidal volume, or increased inspiratory muscle load if the patients inspiratory effort persists after the ventilator has cycled flow off. Conversely, if inspiratory flow persists beyond patient effort which may happen when leaks are present, it can result in unnecessary expiratory work and patient/ventilator dysynchrony.
  • 34 34 34 34 34 18 Most ventilators currently on the market today terminate the inspiratory phase in Pressure Support Ventilation (PS) according to set termination criteria. This criteria is usually a percent of the peak flow for that particular breath. Clinicians have been limited in the past due to the inability to adjust this termination criteria. Expiratory Sensitivity (ESENS) defines the percentage of the projected peak inspiratory flow (VMAX) at which the ventilator terminates flow and thus cycles from inspiration to expiration during spontaneous breathing. A fixed PS termination criterion may potentially result in several clinical issues. If inspiratory flow terminates too early, it can lead to a decreased tidal volume, or increased inspiratory muscle load if the patients inspiratory effort persists after the ventilator has cycled flow off. Conversely, if inspiratory flow persists beyond patient effort which may happen when leaks are present, it can result in unnecessary expiratory work and patient/ventilator dysynchrony.
  • 34 34 34 34 34 18 Most ventilators currently on the market today terminate the inspiratory phase in Pressure Support Ventilation (PS) according to set termination criteria. This criteria is usually a percent of the peak flow for that particular breath. Clinicians have been limited in the past due to the inability to adjust this termination criteria. Expiratory Sensitivity (ESENS) defines the percentage of the projected peak inspiratory flow (VMAX) at which the ventilator terminates flow and thus cycles from inspiration to expiration during spontaneous breathing. A fixed PS termination criterion may potentially result in several clinical issues. If inspiratory flow terminates too early, it can lead to a decreased tidal volume, or increased inspiratory muscle load if the patients inspiratory effort persists after the ventilator has cycled flow off. Conversely, if inspiratory flow persists beyond patient effort which may happen when leaks are present, it can result in unnecessary expiratory work and patient/ventilator dysynchrony.
  • Triggering Rise Time E Sens

    1. 1. Mechanical Ventilation “ Rise Time, E sens, Triggering”
    2. 2. <ul><li>A - work to trigger </li></ul><ul><li>B - rate of rise to pressure adjustment </li></ul><ul><li>C - preventing pressure overshoot and sustaining the breath </li></ul><ul><li>D - transition into expiration </li></ul>Smarter Breath Delivery Pressure A C (PCV Only) D (PS Only) B
    3. 3. Improving Patient-Ventilator Synchrony “ Smart” Rise Time 1.  WOB, specifically insp. muscle effort , associated with inappropriate flow rate during PSV or PCV. 2. less problems associated with flow and achievement of set pressure in response to changes in lung condition as SRT is self- adjusting due to a Pressure Memory Algorithm
    4. 4. <ul><li>Usually applicable in all pressure breaths if available </li></ul><ul><li>Tailors inspiratory rise in pressure ventilation to match patient demand or reach MAP goals </li></ul><ul><li>Should allow rise to be tailored from slow to fast </li></ul>1. Rise to Pressure Adjustment 40 P CIRC cmH 2 O INSP L min EXP PLOT SETUP 30 20 10 0 10 -20 80 60 40 20 0 20 -80 40 60 V . 0 4 8 12s 2 6 10 UNFREEZE Slow rise Moderate rise Fast rise
    5. 5. <ul><li>A - work to trigger </li></ul><ul><li>B - rate of rise to pressure adjustment </li></ul><ul><li>C - preventing pressure overshoot and sustaining the breath </li></ul><ul><li>D - transition into expiration </li></ul>Smarter Breath Delivery Pressure A C (PCV Only) D (PS Only) B
    6. 6. Patient with  Airway Resistance Gas flow is greatest where resistance is low, hence overinflation of normal lung units.  V/Q PvCO 2 = 46 mmHg PvO 2 = 40 mmHg PaO 2 = 70 mmHg PaCO 2 = 45 mmHg PaCO 2 = 43 mmHg PaO2 = 60 mmHg
    7. 7. Without Adjustment of Pressure Rise <ul><li>Most ventilators are sensitive to changes in impedance </li></ul><ul><ul><li>increasing resistance causes pressure to rise more quickly </li></ul></ul>RES = 5 RES = 20 RES = 50 cmH 2 0/L/SEC cmH 2 0/L/SEC cmH 2 0/L/SEC 40 P CIRC cmH 2 O INSP L min EXP PLOT SETUP 30 20 10 0 10 -20 80 60 40 20 0 20 -80 40 60 V . 0 4 8 12s 2 6 10 UNFREEZE
    8. 8. <ul><li>Not all clinicians want to adjust rate of rise (time, interest) </li></ul><ul><li>Smarter rise settings should automatically adjusts flow output as resistance or compliance varies </li></ul><ul><ul><li>maintains similar shape of curve through any patient size or impedance change which reduces the need for intervention </li></ul></ul>RES = 5 RES = 20 RES = 50 cmH 2 0/L/SEC cmH 2 0/L/SEC cmH 2 0/L/SEC 40 P CIRC cmH 2 O INSP L min EXP PLOT SETUP 30 20 10 0 10 -20 80 60 40 20 0 20 -80 40 60 V . 0 4 8 12s 2 6 10 UNFREEZE
    9. 9. <ul><li>A - work to trigger </li></ul><ul><li>B - rate of rise to pressure adjustment </li></ul><ul><li>C - preventing pressure overshoot and sustaining the breath </li></ul><ul><li>D - transition into exhalation </li></ul>Smarter Breath Delivery Pressure A C (PCV Only) D (PS Only) B
    10. 10. Expiratory W.O.B. and auto-PEEP in the COPD Patient MJ Tobin. NEJM 2001; 344: 1986-96.
    11. 11. PS and WOB during Expiration PRESSURE Esens allows the clinician to adjust the ventilator’s onset of expiration to match the patient’s breathing pattern. FLOW PS overshoots target Esens fixed 25% Esens adjusted to 50% Normal Problem resolved 0 100 0 15
    12. 12. Expiratory Sensitivity <ul><li>Pressure support breaths terminate when patient flow decelerates to a percentage of peak flow </li></ul>PS Termination Criteria Flow
    13. 13. Expiratory Sensitivity <ul><li>Leaks can cause inability to terminate pressure supports breaths causing profound asynchrony </li></ul>20% (Set) 35% (Leak Rate) Flow
    14. 14. Expiratory Sensitivity <ul><li>E SENS allows adjustment of the termination criteria for pressure supported breaths </li></ul><ul><ul><li>sets the percent of peak flow that cycles the pressure support breath into exhalation </li></ul></ul><ul><ul><li>helpful in compensating for prolonged inspiratory times when leaks are present or titrating insp times in PS </li></ul></ul><ul><ul><li>can improve synchrony between patient and ventilator </li></ul></ul>20% (Set) 40% (Set) 35% (Leak Rate) Flow
    15. 16. How Much Does It Take To Trigger A Breath? Imagine setting the Flow Sensitivity at 1 LPM: 1 LPM = 16.6ml/100msec or .83 ml/5msecs
    16. 17. Pressure vs Flow Triggering <ul><li>Pressure Triggering </li></ul><ul><ul><li>No gas flow </li></ul></ul><ul><ul><li>Longer delay time </li></ul></ul><ul><ul><li>Poor approach with leaks </li></ul></ul><ul><ul><li>Higher WOB </li></ul></ul><ul><ul><li>Not a mode of ventilation </li></ul></ul><ul><li>Flow Triggering </li></ul><ul><ul><li>Flow at the wye </li></ul></ul><ul><ul><li>Decreased delay </li></ul></ul><ul><ul><li>Electronic signal </li></ul></ul><ul><ul><li>Less WOB </li></ul></ul><ul><ul><li>Not a mode of Ventilation </li></ul></ul>
    17. 18. Flow Triggering Articles <ul><li>Sassoon - flow-by causes lower WOB at 10 cm H2O during CPAP breathing than pressure </li></ul><ul><li>Crit care med 1989 </li></ul><ul><li>Saito - Inspiratory WOB is lower with flow-by and similar to PS of 5 cm H2O </li></ul><ul><li>Crit care med 1990 </li></ul>

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