The ABC’s of Smarter Breath

DeliveryP

ressu

re

A

C (PCV Only)

D (PS Only)B

Current “Standard” Breath Delivery Capabilities

� State-of-the-art gas delivery systems� proportional solenoids

� revolutionary new exhalation valve technologies

� Flexible breath delivery� flow triggering, volume ventilation, PCV and PS

� Advantages� current breath types are accepted and well

understood

� less education needed

New “Standard” Breath Delivery Strategies

� Improved flexibility of accepted breath types� broadened performance with pediatric and/or infant

capabilities

� new pressure support and PCV capabilities allowing titration and improved vent / patient synchrony

Pre

ssu

re

A

C (PCV Only)

D (PS Only)B

A

Work to Trigger

� Great strides have been made in recent years to decrease work to initiate breaths with flow triggering� new data comparing ventilator trigger performance

� Leaks can cause triggering problems� possible in infants, broncho - pleural fistulas, mask ventilation,

and cuff problems

� these leaks result in loss of PEEP and Autocycling

� Flow triggering and increasing flow sensitivity to a level above the leak will maintain PEEP, eliminate Autocycling, and maintain sensitivity

Effects Of Leaks With PEEP

� PEEP = 10 cmH20

� No leak - no Auto-cycling

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Effects Of Leaks With PEEP

� Leak develops – Auto-cycling occurs

� Excessive ventilation and asynchrony results

Effects Of Leaks With PEEP

� If pressure sensitivity is lowered - loss of PEEP develops

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Loss of PEEP

Flow Triggering With Leaks

� Triggering will not occur until leak flow rate + patient Inspiratory flow exceeds flow sensitivity setting

� Auto-cycling is eliminated, PEEP is maintained, and patient sensitivity is enhanced

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Flow Triggering turned on here

740 and 840 Response Time Testing

� ALA / ATS conference in San Diego, April 1999 - Bob Kacmarek abstract presented publishing first comprehensive study comparing ventilator performance

� reported response time tests for 740, 840, Evita, Galileo, Bear 1000, and T-Bird

� looked at response time and negative pressure drop during CPAP, PS, and PCV

PTP (imposed)

Pressure

Time

Response Time or DTOT

PT

What is PT and DTOT in Kacmarek Study?

*

PTP(Imposed)

Pressure

Time

Response Time or DTOT

PT

Greater negative pressure or longer response time = Imposed WOB

*

Pressure Support and Pressure Control in New

Generation Mechanical VentilatorsFuinoY, Goddon S, Kratohvil J, Ritz R, Hess D, Kacmarek, RM, Anesthesia andRespiratory Care, Harvard Medical School, Massachusetts General Hospital, Boston

Am Rev Resp Crit Care Med, April 1999

Flow triggering was set as sensitive as possible without causing autocycling

Pressure Control 300 840 740 Evita 4 Galileo T-Bird

Pt (cm H20) 1.9 1.5 -- 4.4 5.8 4.1

DTOT 80 80 -- 110 160 130

Pressure Support 300 840 740 Evita 4 Galileo T-Bird

Pt (cm H20) 1.8 1.5 4.4 4.5 5.3 4.1

DTOT 80 80 90 110 150 150

Flow and Pressure Triggering During CPAP in New

Generation Mechanical VentilatorsFuinoY, Goddon S, Kratohvil J, Ritz R, Hess D, Kacmarek, RM, Anesthesia andRespiratory Care, Harvard Medical School, Massachusetts General Hospital, BostonAm Rev Resp Crit Care Med, April 1999

Flow or pressure triggering set as sensitive as possible without causing autocycling

Flow Triggering 300 840 Galileo Bear 1000

Pt (cm H20) 2.29 2.28 5.78 4.61

DTOT 240 127 212 253

Pressure Triggering 300 840 Galileo Bear 1000

Pt (cm H20) 3.44 3.07 5.91 5.50

DTOT 238 130 217 184

Without Adjustment of Pressure Rise

� Many ventilators are sensitive to changes in impedance� increasing resistance causes pressure to rise more quickly

� can result in discomfort, or premature termination of PS

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RES = 5 RES = 20 RES = 50cmH20/L/SEC cmH20/L/SEC cmH20/L/SEC

Rise to Pressure Adjustment

� Applicable in all pressure breaths

� Tailors inspiratory rise in pressure ventilation to match patient demand or reach MAP goals

� Should allow rise to be tailored from slow to fast

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Slow rise Moderate rise Fast rise

Optimal Rise to Pressure Adjustments

� Spontaneous breathing patients - easily set

with regard to patient comfort and synchrony

� titrate while watching patient at bedside

� Generally set by watching patient breathing

patterns

� if spontaneous flow demands are explosive - faster rise

� if spontaneous flow demands are relaxed - slower rise

Breathing During PCV

� Patient efforts during the inspiratory phase of PCV can result in fighting and pressure spikes

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Spontaneous Efforts Spontaneous Efforts

PCV W/O Active Valve PCV with Active Valve

Active Exhalation Valve

� During inspiration, the valve is closed with the force of the insp pressure setting

� Allows coughing or spontaneous breathing at upper pressure level by venting excess pressure and flow (PCV or Bi-Level)

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Spontaneous Efforts Spontaneous Efforts

PCV W/O Active Valve PCV with Active Valve

Expiratory Sensitivity

� Pressure support breaths terminate when patient flow decelerates to a selectable percentage of peak flow

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PS Termination Criteria (25%)

Expiratory Sensitivity

� Leaks can cause inability to terminate pressure support breaths, causing profound asynchrony

� I-times too long or too short can also cause asynchronous breathing

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PS Termination Criteria (25%)

Leak rate = 35%

Expiratory Sensitivity

� ESENS allows adjustment of the termination criteria for pressure supported breaths� sets the percent of peak flow that cycles the pressure support breath into

exhalation� especially helpful to match the patient’s desired inspiratory time (with or

w/o leaks)� can improve synchrony between patient and ventilator

25% (Set)40% (Set)

35% (Leak Rate)

Flow

Setting Esens

ESENS 25%

1 2 3 4 5 6

SEC

120

120

V.

LPM

ESENS 35%

100%

50%

25%35%

Back-up timer stops the breath

automatically

Rise to Pressure and Esens

Adjustments

� Easily set with regard to patient comfort and synchrony� titrate while watching patient at bedside

� Set rate of rise first� this helps with comfort early in the breath and

determines peak flow

� Set Esens if longer or shorter inspiratory times are desired during PS

Disconnect Sensitivity

� Adjusts how the machine handles alarms associated with large leaks

� Neonatal patients with uncuffed Endotracheal tubes and some adult tracheostomy patients may have very large leaks.

� Dsens allows you to adjust the minimum amount of Tidal Volume that must return to the machine before it declares a circuit disconnect.

� Available under the more settings tab on the Vent.

Dsens

� When set to 20% - means 80% of volume must return to the machine � More sensitive to leaks

� When set to 95% - means only 5% of volume must return to machine� Less sensitive for leaks

� Can be turned off in NIV mode� Machine can still declare a disconnect, as machine

looks at� Volume� Flow� Pressure