Targets in ARDS

management

Blood Gases

Antonio Pesenti, MDUniversità di Milano

Fondazione IRCCS Ca’ Granda

Ospedale Maggiore Policlinico

Milan, Italy

CCCF 2017

ACUTE RESPIRATORY

DISTRESS SYNDROME IN

ADULTS

By D.G. Ashbaugh et al. The Lancet, 1967.

“THE CLINICAL PATTERN, … INCLUDES

SEVERE DYSPNOEA, TACHYPNOEA,

CYANOSIS THAT IS REFRACTORY TO OXYGEN

THERAPY, LOSS OF LUNG COMPLIANCE, AND

DIFFUSE ALVEOLAR INFILTRATION SEEN ON

CHEST X-RAYS”

At first it was :

try to get the best PaO2

• Intermittent positive-pressure respiration.-

Patient 9 was ventilated with an

experimental volume-cycled respirator

incorporating deep breath at regular

intervals.

• Continuous positive-pressure respiration.

End-expiratory pressures were maintained

at 5-10 cm. water. All 5 patients

demonstrated a rise in P a02 or oxygen

saturation with the use of end-expiratory

pressure.

1988

Guerin C neJM 2013 368:2159

ARDSNet NEJM 2000

Lung protective ventilation

vs. 12 ml/kg

6 ml/kg and/or

Pplat <30

P/F 158±73 176±76 160±68 177±81 165±71 164±88

PaO2 76±23 77±19 74±22 76±23 73±17 75±21

DAY 1 DAY 3 DAY 7

Low VT High VT Low VT High VT Low VT High VT

Oxygenation in the ARMA trial

NEJM 342: 1341: 2000

• A

At 1 hr

At 7 days

Minerva Anestesiol 2010;76:1043

Minerva Anestesiol 2010;76:1043

Minerva Anestesiol 2010;76:1043

Lung Safe Sp O2

• All 95% (94-95) 8.4 (8.3- 8.6)

• Mild 97% (97-98) 7.4 (7.2-7.6)

• Moderate 95% (95-96) 8.3 (8.1-8.5)

• Severe 90% (89-91) 10.1 (9.8-10.4)

Bellani G et al. JAMA. 2016;315(8):788-800.

SpO2% PEEP

15

Permissive Hypoxemia

• How low can we tolerate a PaO2?

• 80% Sat?

• A wise compromise between what we get and what we pay

Grocott et al : N Engl J Med 2009;360:140

Grocott et al N Engl J Med 2009;360:140-9

ADAPTATION TO HYPOBARIC HYPOXEMIA

Large leftward shift of dissociation curve

Hyperventilation, bicarbonate loss, high pH

Control 1

Control 2

ARDS 1

ARDS 2

Mikkelsen et al 2012 AJRCCM

Mikkelsen et al 2012 AJRCCM

Hyperoxemia is bad:

• In cardiac arrest ( Kilgannon J JAMA 2010)

• In AMI (Stub D Circulation 2015)

• In Brain Injury (Helmerhorst H CCM 2015

• etc

GIRARDIS M, JAMA 2016

94-98% 97- 100%

Right oxemia

• How low/ High can we tolerate a PaO2?

• 87% - 97%Sat?

• No supranormal values ( Hb%!!!!!!)

• A wise compromise between what we get and what we pay

Carbon Dioxide: an innocuous gas?

PaO2 min PaCO2 max

Courtesy of Dr Gilles Capellier

Baseline Characteristics of Patients With ARDS

RR

VT

PEEP

PPLAT

VE

20.8

(21.5-21.2)

19.5

(19.0-19.9)

20.7

(20.3-21.1)

22.7

(21.5-23.8)

7.6

(7.5-7.7)

7.8

(7.6-7.9)

7.6

(7.5-7.7)

7.5

(7.3-7.6)

8.4

(8.3-8.6)

7.4

(7.2-7.6)

8.3

(8.1-8.5)

10.1

(9.8-10.4)

23.2

(22.6-23.7)

20.5

(19.8-21.3)

23.1

(22.6-23.7)

26.2

(25.2-27.1)

10.8

(10.6-11.0)

9.3

(9.1-9.6)

10.7

(10.5-11.0)

12.8

(12.3-13.3)

All

(N = 2377)

Mild

(N = 714)

Moderate

(N = 1106)

Severe

(N = 557)

Bellani G et al. JAMA. 2016;315(8):788-800.

Baseline Characteristics of Patients With ARDS

PaO2/FIO2

FIO2

PaCO2

pH

161

(158-163)

246

(244-248)

149

(147-150)

75

(74-77)

0.65

(0.64-0.65)

0.48

(0.47-0.50)

0.62

(0.61-0.63)

0.90

(0.88-0.91)

PEEP8.4

(8.3-8.6)

7.4

(7.2-7.6)

8.3

(8.1-8.5)

10.1

(9.8-10.4)

46.0

(45.4-46.6)

41.5

(40.7-42.2)

45.8

(44.9-46.6)

52.2

(50.7-53.7)

7.33

(7.32-7.33)

7.36

(7.36-7.37)

7.33

(7.32-7.33)

7.27

(7.26-7.29)

Bellani G et al. JAMA. 2016;315(8):788-800.

All

(N = 2377)

Mild

(N = 714)

Moderate

(N = 1106)

Severe

(N = 557)

NEJM 2002:346: 1281

Is permissive Hypercapnia the best solution to

prevent VILI?

Hyperventilation of the “baby lung”80% Dead Space means that the baby lung is

severely hypoperfused.

The rest is ventilated 12 l/min i.e several times normal

ARDS :a pulmonary

microvascular disease