NAVA IN ARDS

Antonio Pesentiantonio.pesenti@unimib.it

Dip.di Medicina Sperimentale

Università Milano-Bicocca

Osp. S. Gerardo, Monza

ISICEM 2012 - 8

Conflicts of Interest

• Maquet: Received research support and consultation fees

• Drager: Received research support and consultation fees

• GE: Received research support and consultation fees

• Patents on CO2 removal by acidification (University of Milan Bicocca)

Control signals for mechanical ventilation in spontaneously breathing patients

Sinderby et al Nature Medicine 1999

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8

0

25

0

0

500

-0.8

0.8

0

Pel,cw

PTPpes

Ti

Flo

w

(l/s

)

Vol

(ml)

Paw

(cm

H2O

)

Pes

(cm

H2O

)The Pressure-Time Product (PTP)

Mechanical WOB Pressure Time Product

PTP is a very good indicator of O2

muscle consumptionField et al J appl Phyisiol 1984

LINEAR RELATIONSHIP BETWEEN Eadi AND Pmusc

Average EAdi (µV,±2s.e.)

0 2 4 6 8 10 12 14 16 18Ave

rag

e P

Mu

sc (

cm

H2O

±2

s.e

.)

0

2

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10

12

Assessing the relationship betweenPmusc and EAdi

Bellani G. et al. submitted

PEI measurement without esophagealpressure

PEIdyn (cmH2O/µV)

0,0 0,5 1,0 1,5 2,0

PE

I occl (cmH2O/µV)

0,0

0,5

1,0

1,5

2,0

2,5

3,0

PEIoccl is a good surrogate of PEIdyn

PEIoccl * Eadi allows to estimate Pmusc

Conclusion

• Diaphragmatci monitoring should become a routinely in patients undergoing spontaneousassisted breathing

• Ultrasound appears promising for «one-shot» assessment

• New tools available for continuous monitoringof the electrical activity of the diaphragm, which can be transalated into pressure

PSV Trial

SUCCESSES

38

FAILURES

10

48 Pts.

Cereda M et al. Crit Care Med. 2000

PSV failures

higher PaCO2 and VElower compliance

during CPPV

Cereda M et al. Crit Care Med. 2000

AirwaysFlow

Airwayspressure

Volume

Edi

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400

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SEVERE ARDS, Crs=10, PSV

NAVA and (A)SYNCHRONY:EXPIRATORY MATCHING

PATRONITI N et al. unpublished

AirwaysFlow

Airwayspressure

Volume

Edi

0

0

0

35

1400

400

20

SEVERE ARDS, Crs=10, NAVA

NAVA and (A)SYNCHRONY:EXPIRATORY MATCHING

PATRONITI N et al. unpublished

NAVA vs PSV DURING ECMO

• We studied 10 severe ARDS patients.

• Patients were 46 ± 13 year-old and 3 were females.

• Crs was 18 ± 8 (range 7-31) mL/cmH20 with PEEP 9 ± 4 cmH20.

• Nine patients were undergoing v-v ECMO and one v-a ECMO with 3.2 ± 0.5 L/min blood flow, which granted 47 ± 17% of total O2consumption

• MV days were 23 ± 17 and ECMO days 19 ± 14.

MAURI T. et al. submitted

NAVA vs PSV DURING ECMO• We tested for 30’ (random order):

1. PSV with expiration cycling time = 30% of flow peak value(PSV30);

2. PSV with cycling time = 1% (PSV1);3. NAVA.

• PEEP, FiO2 and ECMO setting were left unchanged. PSVsupport and NAVA gain levels were chosen to leave tidalvolume (VT) unchanged.

• We measured asynchrony index (AI) = number of asynchronyevents/total respiratory rate (ventilator cycles + wastedefforts) × 100

MAURI T. et al. submitted

NAVA vs PSV DURING ECMO

MAURI T. et al. submitted

NAVA vs PSV DURING ECMO

MAURI T. et al. submitted

NAVA vs PSV DURING ECMO

• Our data indicate that NAVA may ameliorate patient-ventilator interaction and decrease respiratory distress in severe ARDS patients undergoing ECMO.

• NAVA effects are more evident in sicker ptswith extremely low Crs values

MAURI T. et al. submitted

Colombo D

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Pressure Support NAVA

NAVA vs PSV in ARDS

• EaDI has intrinsic variability in Both NAVA and PSV modes

• Nava reflects EaDI variability in TV variability

• PSV does not

Conclusion (s)

Spontaneous breathing does have a role in ARDS

PSV: SOME limitations (low cpl)

NAVA improves synchrony, maintainsoxygenation, protective Vts

Why would NAVA improve oxygenation?