This document discusses various topics related to ARDS including definitions, causes, ventilator strategies, and treatments. It provides the American-European Consensus definition of ARDS which requires bilateral infiltrates, hypoxemia, and no evidence of cardiogenic pulmonary edema. Common causes of ARDS are also mentioned. Regarding ventilator management, low tidal volumes, appropriate PEEP levels based on oxygen needs, and maintaining low plateau pressures are emphasized. Additional strategies discussed include prone positioning, recruitment maneuvers, and neuromuscular blockade. While high frequency oscillatory ventilation and inhaled treatments were investigated, they did not show clear benefits.

1. Dr. JAKEER HUSSAIN
MD,DNB, IDCCM

2. CARDIOGENIC
PULMONARY
OEDEMA.

3. ARDS

4. cardiogenic vs non cardiogenic

5. American-European Consensus ARDS Defination
• An acute condition characterized by bilateral pulmonary
infiltrates and severe hypoxemia in the absence of
evidence for cardiogenic pulmonary edema.
• PaO2/FiO2 <300 = ALI
PaO2/FiO2 <200 = ARDS
• Cardiogenic pulmonary edema must be excluded either
by clinical criteria or by a pulmonary capillary wedge
pressure (PCWP) lower than 18 mm Hg

6. WHAT IS P/F RATIO…
• PAO2/ FIO2
•Fio2 is 0.5, 0.6, 0.7 etc.
•If pao2 140, fio2 0.7
•p/f ratio will b
•140/ 0.7 = 200

7. Limitations of Consensus Definitions
•The chest radiograph is subject to variability in
interpretation,,, & acute is ill defined
•PaO2/FiO2 may vary according to ventilator
parameters, e.g., PEEP, and at extremes of FiO2
•Accuracy in excluding the presence of heart
failure may be influenced by measurement
methodology and timing
•PACs are rarely used
•PCWP may oscillate above and below the cut-off
and may be elevated for reasons other than heart
failure

9. CAUSES OF ARDS

10. Maintaining a low tidal volume
Monitoring plateau pressure
Setting PEEP based on the FiO2 requirement

14. TARGETS OF VENTILAION STRATEGY
• Avoid overdistending lung units by
limiting the inflation volume and
pressure
• Avoid repetitive opening and
collapse by applying adequate PEEP
• Ideally, ventilation would take place in
a “zone of safety”on the deflation limb
of the PV curve

16. The “Baby lung”
ARDS Lung has alveoli
“normal” alveoli
partially aerated alveoli
unaerated alveoli
“Normal” segments inflate easily
Unaerated segments distend poorly
High pressure
Slow response
Normal lung segments may be over-inflated when
ventilated with traditional tidal volumes

18. Ventilatory
strategies of
ARDS

19. NIV

24. FACE MASK VS HELMET NIV MASK
• In a single-center trial, 83 patients with ARDS who required NIV
using full face mask for at least eight hours were randomly
assigned to continue face mask NIV or switch to helmet-
delivered NIV .
• Helmet-delivered NIV involves the administration of positive
pressure and oxygen through a transparent hood that covers the
entire head and face and is sealed with a rubber collar at the neck.
• Helmet-delivered NIV reduced the need for intubation (18
versus 62 percent) in ARDS patients, most of whom had mild or
moderate disease. In addition,
• it was also associated with a higher rate of ventilator-free days,
shorter ICU stay, and lower 90-day mortality without an
increase in adverse effects

26. MODE

27. VENTILLATOR MODE IN ARDS

29. Available evidence is insufficient to confirm
whether PCV offers any advantage over VCV
in improving outcomes for people with ALI
on ventilator

30. TIDAL VOLUME

33. RCT,USA,821 pts
6 vs 12ml/kg

34. • In 2000, the NIH ARDS Network published the findings of their
first randomized, controlled, multi-center clinical trial in 861
patients.
• The trial was designed to compare a lower-tidal-volume
ventilatory strategy (6 mL/kg predicted body weight, plateau
pressure < 30 cm H2O) with a higher tidal volume (12 mL/kg
predicted body weight, plateau pressure <50 cm H2O).
• In this trial, the in-hospital mortality rate was 40% in the 12
mL/kg group and 31% in the 6 mL/kg
• Ventilator-free days and organ failure–free days were also
significantly improved in the low-tidal-volume group. These
findings were truly remarkable, since no prior large randomized
clinical trial of any specific therapy for ALI/ARDS has ever
demonstrated a mortality benefit.

35. PEEP

36. EVIDENCE FOR HIGH PEEP VS

38. PEEP / FIO2 TABLE…

39. PEEP LEVEL

40. RECRUITMENT

41. OPEN LUNG VENTILATION
• Open lung ventilation (OLV) is a strategy that combines
low tidal volume ventilation (LTVV) with a
recruitment maneuver and subsequent titration of
applied PEEP to maximize alveolar recruitment.
• The LTVV and set limits on plateau pressure aim to
mitigate alveolar overdistension, while the applied PEEP
seeks to minimize cyclic atelectasis. Together, these
effects are expected to decrease the risk of ventilator-
associated lung injury.

42. RECRUITMENT MANEUVERS
• a supplement to high peep vent mgt.
• Periodically bt briefly raises the transpulmonary pressures to higher levels than used for
tidal inflation.
• 3 RCTs have tested RMs in ARDS.
• Transient improvement in gas exchange but no apparent sustained benefit.
• Risks –pulmonary / hemodynamic
• 3 negative trials of PEEP has prompted investigators to explore alternative strategies to
guide PEEP titration.
• CT imaging to titrate PEEP risk of pt transfer, cost, radiation exposure
• Electrical impedance tomography(ETT)
• Lung ultrasound
• Pressure-volume relationship analysis—LIP as well as STRESS INDEX.
• Targeted transpulmonary pressure(airway pressure-pleural pressure).

43. Sustained Inflation
Incremental
PEEP
Pressure Control
Ventilation

48. PRONING

49. 466 ARDS patients –PaO2/FiO2 < 150 cmH20
28 day mortality
Prone: 16% vs Control 32.8%
Unadjusted 90-day mortality
Prone: 23.6% vs supine 41.0%

50. 4 RCTS --- 1,573 patients
In the most hypoxaemic 486 patients
PaO2/FiO2 < 100 mmHg
•absolute mortality reduction 10% (6% to 21%)

58. HFOV

60. 548 ARDS patients
PaO2/FiO2 < 200 cmH20 , Fi02 > 0.5
In-hospital mortality
HFOV 47% vs Control 35%
(RR 1.33; 95% CI 1.09 to 1.64; P = 0.005)

61. 548 ARDS patients
–PaO2/FiO2 < 200 cmH20 –PEEP > 5 cmH20
30 day mortality
•HFOV 41.7% vs Control 41.1%
•Difference 0.6%, 95% CI −6.1 to 7.5

64. 340 ARDS patients
PaO2/FiO2 < 150 mmHg
Adjusted Mortality at Day 90
NMB: 31.6% vs placebo: 40.7%
(95% CI 0.48 to 0.98; P = 0.04)

66. 282 patients with ALI
Aerosolized albuterol vs saline
Ventilator-free days
•albuterol 14.4 vs control 16.6 d
(95% CI difference –4.7 to 0.3 d: P = 0.087)
Hospital death
albuterol 23.0% vs control 17.7%
(95% CI difference –4.0 to 14.7%,P=0.30)

67. INVERSE RATIO VENTILATION
• PCIRV increases mean airway pressures and improves
oxygenaion
• Little benefit
• Auto PEEP
• Haemodynamic instability

68. PARTIAL LIQUID VENTILATION
•No benefit in mortality

69. summary

73. Repeating
again