ARDS

1. VENTILATORY
MANAGEMANT OF ARDS
DR.L.SHANTHI M.D., D.A (SENIOR RESIDENT IN
ANAESTHESIOLOGY GOVT MEDICAL COLLEGE AND
HOSPITAL, KALLAKURUCHI)

2. ARDS
2
INTRODUCTION
ETIOLOGY
PATHOPHYSIOLOGY
DIAGNOSIS
GOALS OF TREATMENT
MANAGEMENT

3. INTRODUCTION
PRESENTATION
TITLE
3
ARDS(ACUTE RESPIRATORY DISTRESS
SYNDROME) characterized by life threatening
impairment of pulmonary gas exchange
HYPOXEMIA
HYPERCAPNIA RESP. ACIDOSIS

4. 4
PULMONARY CAUSES EXTRA-PULMONARY
CAUSES
• PULMONARY INFECTION • SEPSIS
• PULMONARY ASPIRATION • PANCREATITIS
• MASSIVE BLOOD
TRANSFUSION
• DROWNING
• DRUG OVERDOSE
• INHALATION OF TOXIC
FUMES
ETIOLOGY:-

5. PATHO-PHYSIOLOGY
• Initial insult with subsequent inflammatory response
• Endothelial damage and increased pulmonary capillary permeability
• Proliferative stage
• Fibrotic Stage: Recruits fibroblasts and implements repair
mechanism that causes intra-alveolar fibrosis and capillary obliteration
• Intra-alveolar architectural change l/t prolonged mechanical ventilation and
increased mortality.
5

6. ARDS DEFINITION BY BERLIN DIAGNOSTIC
CRITERIA

7. GOALS OF TREATMENT:-
7
• TO DECREASE THE SHUNT FRACTION
• TO INCREASE O2 DELIVERY
• TO DECREASE 02 CONSUMPTION
• TO AVOID FURTHER LUNG INJURY
REQUIREMENT OF VENTILATION IN ARDS:-
• PaO2 < 60mmHg / Arterial Oxygenation < 88%
• PaO2/FiO2 < 100mmHg

8. MANAGEMENT
• 1.Ventilator Settings
• 2. Position
• 3. Infection control
• 4.Supportive measures
8
REQUIREMENT OF VENTILATION IN ARDS:-
• PaO2 < 60mmHg / Arterial Oxygenation < 88%
• PaO2/FiO2 < 100mmHg

9. NON VENTILATORY
MANAGEMENTS
• 1. PRONING :- 1ST LINE THERAPY FOR MODERATE TO SEVERE ARDS & PREVENTION
OF VALI(VENTILATOR ASSOCIATED LUNG INJURY)
*EARLY PRONING within 48hrs of onset of SEVERE ARDS
*PROLONGED PRONING (@least 16hrs/day)
• CRITERIA TO STOP PRONING:-
• IMPROVEMENT IN OXYGENATION FOR LAST 4hrs IN SUPINE POSITON
i) PaO2 / FiO2 >150mmHg
ii) PEEP of <10cms of H2O
iii) FiO2 <0.6
9

10. INFECTION CONTROL
• ADVANCED INFECTION CONTROL:-
1. CT-CHEST
2. BLOOD CULTURE
3. BAL(BRONCHO-ALVEOLAR LAVAGE) or ET ASPIRATE
4. WHOLE BODY CT SCAN
5. TRANS-ESOPHAGEAL ECHO : To exclude endocarditis and pericardial
effusion.
1 0

11. SUPPORTIVE MEASURES
• NM BLOCKADE:
 PaO2/FiO2 <150mmHg requires early continuous infusion of muscle relaxants
for 48hrs.
Reduces atelecto-trauma to lung caused by pt – ventilator dysynchorony
• SEDATION:-
 Required for minimum 48hrs when pt is on ventilator.
• FLUID CONSERVATIVE THERAPY:-
Target CVP <4cms of H2O.
• EARLY AND LOW DOSE STEROIDS(METHYL PREDINISOLONE = 1mg/kg/wt)
• DVT PROPHYLAXIS
• NUTRITIONAL SUPPORT(increase fat and decrease carbohydrate)
• BACK REST ELEVATION TO 20-40 degrees
1 1

12. NOVEL VENTILATION STRATEGIES
1 2
1.INVASIVE STRATEGIES:-
*APRV(AIRWAY PRESSURE RELEASE VENTILATION)
*HFOV(HIGH FREQUENCY OSCILLATORY VENTILAION)
2. OTHER STRATEGIES:-(USED IN MILD TO MODERATE ARDS)
*C-PAP (CONTINOUS POSITIVE AIRWAY PRESSURE)
*BI-PAP(BI-LEVEL POSITIVE AIRWAY PRESSURE)
*PROPORTIONAL ASSIST VENTILATION
*HFNO(HIGH FLOW NASAL OXYGEN THERAPY)

13. How CPAP works for Hypoxemia
Cause for hypoxemia is
1.Closure of alveoli,
2.Widening of Gap between alveolar
epithelium & Capillary endothelium.
CPAP:-
*Opens up the collapsed alveoli
& recruits the alveoli.
* Reduces distance & shunt
Thereby it improves oxygenation.

14. NIV (NON INVASIVE VENTILATION)
• Definitions: Non-invasive ventilation (NIV) is a method of respiratory support,
in which a mask is used as the main interface, which can be easily applied and
easily disconnected from the patient’s respiratory tract.
• Emerging evidences in COVID has shown that NIV has a more significant and
positive role than initially thought.
• It may be of benefit to patients early in the disease process, may
prevent deterioration and reduce the need for invasive ventilation at all.
• It may act like a “bridging or holding” measure prior to mechanical ventilation

15. TYPES OF NIV
INTERFACES
• Nasal mask, oronasal mask, total
face mask, helmet NIV

16. NIV
1. CPAP = EPAP (or) PEEP
 Constant pressure is maintained throughout the respiratory
cycle with no additional inspiratory support.
2. BI-PAP = EPAP + IPAP
CPAP = Continuous Positive Airway Pressure
EPAP = Expiratory positive airway pressure
PEEP = Positive end expiratory pressure
IPAP = Inspiratory Positive Airway Pressure
PS = IPAP - EPAP

17. Indication for Weaning from NIV
• “Time limited breaks” for eating, trip to restroom are allowed.
• When the indication is resolved, When the ABG is
normalised, pt WOB has improved significantly.
• RR < 25, HR < 110, PH > 7.35, SpO2 > 90% with
FiO2 0.4 to 0.5

18. Indication to convert into mechanical
ventilation
• Inability to maintain airway patency in unconscious patients.
• Hemodynamic Instability (Arrhythmia, hypotension,
MIShock).
• Inability to protect the airway against aspiration.
• Failure to ventilate.
• Failure to oxygenate.
• Anticipation of a deteriorating course that will eventually lead
to respiratory failure.

19. MEANS & MODES OF
VENTILATION
1. VOLUME CYCLED : DELIVERS CONSTANT VOLUME WITH EACH
BREATH
2. PRESSURE CYCLED : DELIVERS CONSTANT PRESSURE WITH EACH
BREATH
3. COMBINATION OF VOLUME & PRESSURE CYCLED
ADJUSTABLE VENTILATORY SETTINGS : i)RR
ii)TV
iii)TRIGGER SENSTIVITY
iv)FLOW RATE
v)WAVEFORM
vi)I/E RATIO
1 9

20. VOLUME CYCLED
1. VOLUME CONTROL VENTILATION(VCV) : *SIMPLEST , FULL MECHANICAL
VENTILATION
*EACH INSPIRATORY EFFORT BEYOND
THE SET SENSITIVITY THRESHOLD TRIGGERS DELIVERY OF FIXED TV. IF PTS
DOES NOT TRIGGER VENTILATOR INITIATES BREATH ENSURES SET RR
• SIMV(SYNCHRONIZED INTERMITTENT MANDATORY VENTILATION) : PT
EFFORTS ABOVE SET RR ARE UNASSISTED.
• IN ARDS, IT LIMITS DISTENDING PRESSURE OF THE LUNGS.
• PCV(PRESSURE CONTROL VENTILATION) : PRESSURE CYCLED FORM OF
A/C. EACH INSPIRATORY EFFORT BEYOND SET SENSITIVITY THRESHOLD
DELIVERS FULL PRESSURE SUPPORT MAINTAINED FOR FIXED
INSPIRATORY TIME.
• PSV(PRESSURE SUPPORT VENTILATION)
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PRESSURE CYCLED

21. IPPV
• Set: TV, rate, Fi02, PEEP,
• No capacity for the
patient to trigger a breath
• Uncomfortable if patient
not fully sedated &/
paralysed
• Suitable only for patients
who have no ability to
breathe spontaneously

23. VENTILATOR SETTINGS:-
HOW TO SET TV?
• Normally = 6-8 ml/kg of PBW.
• Titrated to plateau pressure <30cm of H20
How to start RR?
• 10-16 breaths /min titrated to desired PaCO2
How to start FiO2?
• Started at 100% and weaned at the earliest to < 50%
based SpO2 (or) ABG PaO2 88-95%
How to start Flowrate?
Flow rate 20 to 30 L/min &Inspiratory time 0.5 to 2 sec titrared to I:E ratio = 1:2 to 1:3

24. PressureVolumeLoop
• LIP: is identified by the intersection of two lines & it
decides the PEEP
• Look at the “beaking” above UIP

25. Pressure-volumeloop
Lower inflection point(LIP)
Canbe thought of asthe
minimum baseline pressure
(PEEP)
needed for optimal
alveolar recruitment
Upper inflection point(UIP)
abovethis pressure,
additional alveolarrecruitment
requires disproportionate
increases in applied
airway pressure
Compliance (C)
is markedly reduced in the
injured lung on the right as
compared to the normallung
on the left
Normal
lung
ARDS

26. 2 6
HEMODYNAMIC EFFECTS OF PEEP

27. LUNG PROTECTIVE VENTILATION
2 7
• To avoid VOLUTRAUMA , Baro-trauma and Atelecto-trauma to lung.
1. LOW TIDAL VOLUME(6ml /kg PBW)
PBW(Predicted Body Weight):-
MALES= 50+[(0.91)x(height in cms – 152.4)]
FEMALES = 45 +[(0.91)x(height in cms – 152.4)]
2. BALANCED RR(20-30/min)
3. TARGETTING LOW PLATEAU PRESSURES(PP <32cms of H2O)
DYNAMIC ADJUSTMENT OF OPTIMAL PEEP(5-24cms of H2O)
(ARDS NET PROTOCOL)- PEEP & FiO2 titrated to achieve target of
SpO2 88-95% (or) PaO2 55-80mmHg & low PP

28. 2 8
5. VENTILATOR DRIVING PRESSURES <14cms of H2O
DRIVING PRESSURES = TV/ PULMONARY COMPLIANCE
(OR)
Pd = PLATEAU PRESSURE – PEEP
6. RECRUITEMENT MANUVERS :-
INVOLVE INCREASING AIRWAY PRESSURE FOR A SHORTER PERIOD OF
TIME (7-8S) TO EXPAND COLLAPSED ALVEOLI FOR BETTER GAS EXCHANGE.
• INCREASE TV WITH DECREASE RR (in VCV)
(or)
• GRADUAL INCREASE IN PEEP WHILE MAINTAINING DRIVING PRESSURE TILL PIP REACHES 40cms of
H20.
CONTD,

29. ARDS net PROTOCOL
NIH NHLBI ARDS Clinical Network

30. WEANING FROM MV
• Patient Hemodynamically stable.
• Adequate PaO2 on FiO2 <0.5 with PEEP <7.5 cms of H2O.
• Minute Ventilation <20L/min.
↓
T-PIECE VENTILATION FOR 2hrs
↓
EXTUBATION & VITALS MONITORING
3 0

31. COMPLICATION OF MV IN ARDS
1. VALI (VENTILATOR ASSOCIATED LUNG INJURY)
2. VAP (VENTILATOR ASSOCIATED PNEUMONIA)
3. RT VENT DYSFUNCTION , ACUTE COR PULMONALE
4. PLEURAL EFFUSION
5. BAROTRAUMA/ PNEUMOTHORAX
6. DAMAGE TO ORGAN SYSTEMS
7. PROLONGED SEDATION AND IMMOBILIZATION
8. FIBRO-PROLIFERATIVE RESPONSE OF LUNG PARENCHYMA
3 1

32. COMPLICATION OF ARDS
1. LUNG BARO-TRAUMA d/t HIGH PEEP
2. PROLONGED MV  TRACHEOSOTOMY
3. POST EXTUBATION LARYNGEAL EDEMA AND SUBGLOTTIC STENOSIS
4. NOSOCOMIAL INFECTIONS WITH ANTI-BIOTIC RESISTANCE
i)PNEUMONIA
ii) IV line SEPSIS
iii) UTI
5. DVT
6. MUSCLE WEAKNESS
7. PTSD (POST TRAUMA STRESS DISORDER)
8. RENAL FAILURE
9. DEATH (d/t SEPSIS AND MODS)
3 2

33. ARDS MX ALGORITHM
• A/C MODE : TV = 6ml/kg/PBW with RR = 25-30/min,
f = 60L/min,
FiO2 = 1.0, PEEP = 15cms of H2O
↓
Once PaO2 >90% then reduce FiO2 gradually
↓
PEEP is decreased in increments of 2.5cms of H2O as
tolerated to find the least PEEP a/w PaO2 >90% on FiO2 <0.6
3 3

34. 3 4
REFERENCE
S
1. NATIONAL LIBRARY OF MEDICINE : Acute Respiratory Distress Syndrome
Matthew Diamond; Hector L. Peniston; Devang Sanghavi; Sidharth
Mahapatra.(October 30,2022)
2. Overview of Mechanical Ventilation
By Bhakti K. Patel , MD, University of Chicago
Last review/revision May 2022 | Modified Sep 2022
3. Evidence-Based Mechanical Ventilatory Strategies in ARDSAdnan Liaqat,
1,†
Matthew
Mason,
2
Brian J. Foster,
1
Sagar Kulkarni,
1
Aisha Barlas,
3
Awais M.
Farooq,
1
Pooja Patak,
1
Hamza Liaqat,
4
Rafaela G. Basso,
1
Mohammed S.
Zaman,
1
and Dhaval Pau
1,*†
4. The standard of care of patients with ARDS: ventilatory settings and rescue
therapies for refractory hypoxemia
Thomas Bein, 1 Salvatore Grasso,2 Onnen Moerer,3 Michael Quintel,3 Claude Guerin,4,5 Maria Deja,6 Anita
Brondani,7 and Sangeeta Mehta7

35. THANK YOU
DEPARTMENT OF ANAESTHESIOLOGY