Acute Respiratory Distress Syndrome.
Case presentation
Dr. Adel Hassan
Sen. Consult. Anesthesiologist
HOD Anesthesia & ICU.
Kalba Hospital,
MOH.
31st March 2014
F. 35ys , 300 Kgs, Lt. TIBIA/FIBULA Fx (Impacted In place).
8th D -in pat. w.- after admission, sudden severe hypoxia PH 7.22
PaCO2 =72 mmhg PaO2=43 mmhg HCO36 , Unconscious.
Anesthesia on duty was called to IPW. Supported
ventilation shifted pt. to ICU. Management started as
will be discussed later.
Acute Respiratory Failure
• Failure in one or both gas exchange functions:
oxygenation and carbon dioxide elimination
• In practice:
PaO2<60mmHg or PaCO2>46mmHg
• Derangements in ABGs and acid-base status
Acute Respiratory Failure
• Hypercapnic v Hypoxemic respiratory failure
• ARDS and ALI
Hypercapnic Respiratory Failure
(PAO2 - PaO2)
Alveolar
Hypoventilation
V/Q abnormality
PI max
increasednormal
Nl VCO2
PaCO2 >46mmHg
Not compensation for metabolic alkalosis
Central
Hypoventilation
Neuromuscular
Problem
VCO2
V/Q
Abnormality
Hypermetabolism
Overfeeding
Hypercapnic Respiratory Failure
(PAO2 - PaO2)
Alveolar
Hypoventilation
V/Q abnormality
PI max
increasednormal
Nl VCO2
PaCO2 >46mmHg
Not compensation for metabolic alkalosis
Central
Hypoventilation
Neuromuscular
Problem
VCO2
V/Q
Abnormality
Hypermetabolism
Overfeeding
Hypercapnic Respiratory Failure
Alveolar
Hypoventilation
Brainstem respiratory depression
Drugs (opiates)
Obesity-hypoventilation syndrome
PI max
Central
Hypoventilation
Neuromuscular
Disorder
nlPI max
Critical illness polyneuropathy
Critical illness myopathy
Hypophosphatemia
Magnesium depletion
Myasthenia gravis
Guillain-Barre syndrome
Hypercapnic Respiratory Failure
(PAO2 - PaO2)
Alveolar
Hypoventilation
V/Q abnormality
PI max
increasednormal
Nl VCO2
PaCO2 >46mmHg
Not compensation for metabolic alkalosis
Central
Hypoventilation
Neuromuscular
Disorder
VCO2
V/Q
Abnormality
Hypermetabolism
Overfeeding
Hypercapnic Respiratory Failure
V/Q abnormality
Increased Aa gradient
Nl VCO2
VCO2
V/Q
Abnormality
Hypermetabolism
Overfeeding
Hypercapnic Respiratory Failure
V/Q abnormality
Increased Aa gradient
Nl VCO2
VCO2
V/Q
Abnormality
Hypermetabolism
Overfeeding
• Increased dead space ventilation
• advanced emphysema
• PaCO2 when Vd/Vt >0.5
• Late feature of shunt-type
• edema, infiltrates
Hypercapnic Respiratory Failure
V/Q abnormality
Increased Aa gradient
Nl VCO2
VCO2
V/Q
Abnormality
Hypermetabolism
Overfeeding
• VCO2 only an issue in pts with ltd
ability to eliminate CO2
• Overfeeding with carbohydrates
generates more CO2
Hypoxemic Respiratory Failure
Is PaCO2 increased?
Hypoventilation (PAO2 - PaO2)?
Hypoventilation
alone
Respiratory drive
Neuromuscular dz
Hypovent plus
another
mechanism
Shunt
Inspired PO2
High altitude
FIO2
(PAO2 - PaO2) No
NoYes
Is low PO2
correctable
with O2?
V/Q mismatch
No Yes
Yes
The Case of Patient ES
77F s/p MVC.
Injuries include multiple L rib fxs, L hemopneumothorax
s/p chest tube placement, L iliac wing fx.
PMH: atrial arrhythmia, on coumadin. INR>2
HD#1
RR 30s and shallow. Pain a/w breathing deeply.
Placed on BiPAP overnight
PID#1
BiPAP 80%: 7.45/48/66/32/+10
Hypoxemic Respiratory Failure
Is PaCO2 increased?
Hypoventilation (PAO2 - PaO2)?
Hypoventilation
alone
Respiratory drive
Neuromuscular dz
Hypovent plus
another
mechanism
Shunt
Inspired PO2
High altitude
FIO2
(PAO2 - PaO2) No
NoYes
Is low PO2
correctable
with O2?
V/Q mismatch
No Yes
Yes
Hypoxemic Respiratory Failure
V/Q mismatch
V/Q mismatch DO2/VO2
Imbalance
PvO2>40mmHg PvO2<40mmHg
DO2: anemia, low CO
VO2: hypermetabolism
Hypoxemic Respiratory Failure
V/Q mismatch
SHUNT
V/Q = 0
DEAD SPACE
V/Q = ∞
Atelectasis
Intraalveolar filling
Pneumonia
Pulmonary edema
Pulmonary embolus
Pulmonary vascular dz
Airway dz
(COPD, asthma)
Intracardiac shunt
Vascular shunt in lungs
ARDS
Interstitial lung dz
Pulmonary contusion
Hypoxemic Respiratory Failure
V/Q mismatch
SHUNT
V/Q = 0
DEAD SPACE
V/Q = ∞
Atelectasis
Intraalveolar filling
Pneumonia
Pulmonary edema
Pulmonary embolus
Pulmonary vascular dz
Airway dz
(COPD, asthma)
Intracardiac shunt
Vascular shunt in lungs
ARDS
Interstitial lung dz
Pulmonary contusion
Hypoxemic Respiratory Failure
Acute Respiratory Distress Syndrome
• Severe ALI
• B/L radiographic
infiltrates
• PaO2/FiO2 <200mmHg
(ALI 201-300mmHg)
• No e/o L Atrial P;
PCWP<18
Hypoxemic Respiratory Failure
Acute Respiratory Distress Syndrome
• Develops ~4-48h
• Persists days-wks
• Diagnosis:
– Distinguish from
cardiogenic edema
– History and risk
factors
Inflammatory
Alveolar Injury
Inflammatory
Alveolar Injury
Pro-inflmm cytokines
(TNF, IL1,6,8)
Inflammatory
Alveolar Injury
Pro-inflmm cytokines
(TNF, IL1,6,8)
Neutrophils - ROIs
and proteases
damage capillary
endothelium and
alveolar epithelium
Inflammatory
Alveolar Injury
Fluid in interstitium
and alveoli
Pro-inflmm cytokines
(TNF, IL1,6,8)
Neutrophils - ROIs
and proteases
damage capillary
endothelium and
alveolar epithelium
Inflammatory
Alveolar Injury
Fluid in interstitium
and alveoli
• Impaired gas exchange
•  Compliance
•  PAP
Pro-inflmm cytokines
(TNF, IL1,6,8)
Neutrophils - ROIs
and proteases
damage capillary
endothelium and
alveolar epithelium
Hypoxemic Respiratory Failure
Acute Respiratory Distress Syndrome
Exudative phase Fibrotic phaseProliferative phase
Diffuse alveolar damage
Hypoxemic Respiratory Failure
Acute Respiratory Distress Syndrome
Direct Lung Injury
• Infectious pneumonia
• Aspiration, chemical pneumonitis
• Pulmonary contusion, penetrating lung injury
• Fat emboli
• Near-drowning
• Inhalation injury
• Reperfusion pulmonary edema s/p lung transplant
Hypoxemic Respiratory Failure
Acute Respiratory Distress Syndrome
Indirect Lung Injury
• Sepsis
• Severe trauma with shock / hypoperfusion
• Burns
• Massive blood transfusion
• Drug overdose: ASA, cocaine, opioids, phenothiazines, TCAs.
• Cardiopulmonary bypass
• Acute pancreatitis
Hypoxemic Respiratory Failure
Acute Respiratory Distress Syndrome
Complications
• Barotrauma
• Nosocomial pneumonia
• Sedation and paralysis  persistent MS
depression and neuromuscular weakness
Hypoxemic Respiratory Failure
Acute Respiratory Distress Syndrome
• 861 patients, 10 centers
• Randomized
• Tidal Vol 12mL/kg PDW,
PlatP<50cmH2O
• Tidal Vol 6mL/kg PDW,
PlatP<30cmH2O
• NNT 12
• 31% mortality v 39.8%
• 65.7% breathing without assistance by day 28 v 55%
• Significantly more ventilator-free days
• Significantly more days without failure of nonpulmonary
organs/systems

ARDS - trauma

  • 1.
    Acute Respiratory DistressSyndrome. Case presentation Dr. Adel Hassan Sen. Consult. Anesthesiologist HOD Anesthesia & ICU. Kalba Hospital, MOH. 31st March 2014
  • 3.
    F. 35ys ,300 Kgs, Lt. TIBIA/FIBULA Fx (Impacted In place). 8th D -in pat. w.- after admission, sudden severe hypoxia PH 7.22 PaCO2 =72 mmhg PaO2=43 mmhg HCO36 , Unconscious. Anesthesia on duty was called to IPW. Supported ventilation shifted pt. to ICU. Management started as will be discussed later.
  • 4.
    Acute Respiratory Failure •Failure in one or both gas exchange functions: oxygenation and carbon dioxide elimination • In practice: PaO2<60mmHg or PaCO2>46mmHg • Derangements in ABGs and acid-base status
  • 5.
    Acute Respiratory Failure •Hypercapnic v Hypoxemic respiratory failure • ARDS and ALI
  • 6.
    Hypercapnic Respiratory Failure (PAO2- PaO2) Alveolar Hypoventilation V/Q abnormality PI max increasednormal Nl VCO2 PaCO2 >46mmHg Not compensation for metabolic alkalosis Central Hypoventilation Neuromuscular Problem VCO2 V/Q Abnormality Hypermetabolism Overfeeding
  • 7.
    Hypercapnic Respiratory Failure (PAO2- PaO2) Alveolar Hypoventilation V/Q abnormality PI max increasednormal Nl VCO2 PaCO2 >46mmHg Not compensation for metabolic alkalosis Central Hypoventilation Neuromuscular Problem VCO2 V/Q Abnormality Hypermetabolism Overfeeding
  • 8.
    Hypercapnic Respiratory Failure Alveolar Hypoventilation Brainstemrespiratory depression Drugs (opiates) Obesity-hypoventilation syndrome PI max Central Hypoventilation Neuromuscular Disorder nlPI max Critical illness polyneuropathy Critical illness myopathy Hypophosphatemia Magnesium depletion Myasthenia gravis Guillain-Barre syndrome
  • 9.
    Hypercapnic Respiratory Failure (PAO2- PaO2) Alveolar Hypoventilation V/Q abnormality PI max increasednormal Nl VCO2 PaCO2 >46mmHg Not compensation for metabolic alkalosis Central Hypoventilation Neuromuscular Disorder VCO2 V/Q Abnormality Hypermetabolism Overfeeding
  • 10.
    Hypercapnic Respiratory Failure V/Qabnormality Increased Aa gradient Nl VCO2 VCO2 V/Q Abnormality Hypermetabolism Overfeeding
  • 11.
    Hypercapnic Respiratory Failure V/Qabnormality Increased Aa gradient Nl VCO2 VCO2 V/Q Abnormality Hypermetabolism Overfeeding • Increased dead space ventilation • advanced emphysema • PaCO2 when Vd/Vt >0.5 • Late feature of shunt-type • edema, infiltrates
  • 12.
    Hypercapnic Respiratory Failure V/Qabnormality Increased Aa gradient Nl VCO2 VCO2 V/Q Abnormality Hypermetabolism Overfeeding • VCO2 only an issue in pts with ltd ability to eliminate CO2 • Overfeeding with carbohydrates generates more CO2
  • 13.
    Hypoxemic Respiratory Failure IsPaCO2 increased? Hypoventilation (PAO2 - PaO2)? Hypoventilation alone Respiratory drive Neuromuscular dz Hypovent plus another mechanism Shunt Inspired PO2 High altitude FIO2 (PAO2 - PaO2) No NoYes Is low PO2 correctable with O2? V/Q mismatch No Yes Yes
  • 14.
    The Case ofPatient ES 77F s/p MVC. Injuries include multiple L rib fxs, L hemopneumothorax s/p chest tube placement, L iliac wing fx. PMH: atrial arrhythmia, on coumadin. INR>2 HD#1 RR 30s and shallow. Pain a/w breathing deeply. Placed on BiPAP overnight PID#1 BiPAP 80%: 7.45/48/66/32/+10
  • 15.
    Hypoxemic Respiratory Failure IsPaCO2 increased? Hypoventilation (PAO2 - PaO2)? Hypoventilation alone Respiratory drive Neuromuscular dz Hypovent plus another mechanism Shunt Inspired PO2 High altitude FIO2 (PAO2 - PaO2) No NoYes Is low PO2 correctable with O2? V/Q mismatch No Yes Yes
  • 16.
    Hypoxemic Respiratory Failure V/Qmismatch V/Q mismatch DO2/VO2 Imbalance PvO2>40mmHg PvO2<40mmHg DO2: anemia, low CO VO2: hypermetabolism
  • 17.
    Hypoxemic Respiratory Failure V/Qmismatch SHUNT V/Q = 0 DEAD SPACE V/Q = ∞ Atelectasis Intraalveolar filling Pneumonia Pulmonary edema Pulmonary embolus Pulmonary vascular dz Airway dz (COPD, asthma) Intracardiac shunt Vascular shunt in lungs ARDS Interstitial lung dz Pulmonary contusion
  • 18.
    Hypoxemic Respiratory Failure V/Qmismatch SHUNT V/Q = 0 DEAD SPACE V/Q = ∞ Atelectasis Intraalveolar filling Pneumonia Pulmonary edema Pulmonary embolus Pulmonary vascular dz Airway dz (COPD, asthma) Intracardiac shunt Vascular shunt in lungs ARDS Interstitial lung dz Pulmonary contusion
  • 19.
    Hypoxemic Respiratory Failure AcuteRespiratory Distress Syndrome • Severe ALI • B/L radiographic infiltrates • PaO2/FiO2 <200mmHg (ALI 201-300mmHg) • No e/o L Atrial P; PCWP<18
  • 20.
    Hypoxemic Respiratory Failure AcuteRespiratory Distress Syndrome • Develops ~4-48h • Persists days-wks • Diagnosis: – Distinguish from cardiogenic edema – History and risk factors
  • 22.
  • 23.
  • 24.
    Inflammatory Alveolar Injury Pro-inflmm cytokines (TNF,IL1,6,8) Neutrophils - ROIs and proteases damage capillary endothelium and alveolar epithelium
  • 25.
    Inflammatory Alveolar Injury Fluid ininterstitium and alveoli Pro-inflmm cytokines (TNF, IL1,6,8) Neutrophils - ROIs and proteases damage capillary endothelium and alveolar epithelium
  • 26.
    Inflammatory Alveolar Injury Fluid ininterstitium and alveoli • Impaired gas exchange •  Compliance •  PAP Pro-inflmm cytokines (TNF, IL1,6,8) Neutrophils - ROIs and proteases damage capillary endothelium and alveolar epithelium
  • 27.
    Hypoxemic Respiratory Failure AcuteRespiratory Distress Syndrome Exudative phase Fibrotic phaseProliferative phase Diffuse alveolar damage
  • 28.
    Hypoxemic Respiratory Failure AcuteRespiratory Distress Syndrome Direct Lung Injury • Infectious pneumonia • Aspiration, chemical pneumonitis • Pulmonary contusion, penetrating lung injury • Fat emboli • Near-drowning • Inhalation injury • Reperfusion pulmonary edema s/p lung transplant
  • 29.
    Hypoxemic Respiratory Failure AcuteRespiratory Distress Syndrome Indirect Lung Injury • Sepsis • Severe trauma with shock / hypoperfusion • Burns • Massive blood transfusion • Drug overdose: ASA, cocaine, opioids, phenothiazines, TCAs. • Cardiopulmonary bypass • Acute pancreatitis
  • 30.
    Hypoxemic Respiratory Failure AcuteRespiratory Distress Syndrome Complications • Barotrauma • Nosocomial pneumonia • Sedation and paralysis  persistent MS depression and neuromuscular weakness
  • 31.
    Hypoxemic Respiratory Failure AcuteRespiratory Distress Syndrome • 861 patients, 10 centers • Randomized • Tidal Vol 12mL/kg PDW, PlatP<50cmH2O • Tidal Vol 6mL/kg PDW, PlatP<30cmH2O • NNT 12 • 31% mortality v 39.8% • 65.7% breathing without assistance by day 28 v 55% • Significantly more ventilator-free days • Significantly more days without failure of nonpulmonary organs/systems