Presentation on Respiratory Failure | Jindal Chest Clinic

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Respiratory Failure
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Respiratory Failure

• Inability of the respiratory system to maintain
  normal arterial gas exchange i.e.
• Failure to maintain normal arterial oxygen and
  carbon-di-oxide tensions
• Type I Hypoxemia (Low PaO2,
• Normal or low PaCO2)
• Type II Hypoxia and Hypercapnia
• (Low PaO2 and raised Pa CO2)

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Causes Pathophysiology

• Impairment of lung ventilation and/or perfusion
  due to diseases of lung, chest wall, pulmonary
  circulation or ventilation control.
• Results in low oxygen uptake or impaired CO2
  removal from arterial blood
• Both type I and type II respir failure can be
  acute or chronic

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OXYGEN TRAVEL

• PaO2 (mmHg) 
• Atmospheric air 150
• Trachea Ventilation 120
• Alveoli 100
• Art. Blood Diffusion 95
• Transport
• Tissues Delivery 35-40
• Venous blood Utilization 35-40

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OXYGEN DELIVERY
OXYGEN DEMAND
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Causes of Acute Respiratory Failure

• Ac exacerbation of COPD
• Acute Sever Asthma
• Severe pneumonia sepsis
• Acute Respiratory Distress Syndrome
• Pneumothorax
• Acute chest infure, flail chest
• Drugs poisoning Neuroventilatory failure
• Pulm thromboembolism

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Causes of Chronic Respiratory Failure

• Severe COPD
• Advanced interstitial lung diseases silicosis,
  pulmonary fibrosis of any cause
• Extensive bronchiectasis
• Kyphoscoliosis
• Neuromuscular diseases Myasthenia gravis,
  muscular dystrophies
• Obesity and Sleep Apnea Syndrome

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Diagnosis

• Presence of a disease causing respiratory
  failure. Investigations for underlying
  respiratory/ non-respiratory disease
• Clinical signs of hypoxemia and/ or hypercapnia
  Oxymetry (O2 saturation measurement, lt 90)
• Assessment of Blood gas tensions i.e partial
  pressures (PaO2 lt90 mmHg
• PaCO2 gt 44mmHg)
• Investigations for systemic effects of hypoxia
  and hypercapnia LFT, RFT, Cardiac, Hematological
  etc)

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Clinical Features

• Hypoxia Fatigue, restlessness, cyanosis,
• tachypnea, tachcardia, sweating,
• Later cardiac ectopics, arrhythmias,
• bradycardia, shock, impaired consciousness,
• coma
• Hypercapnia Headache, sweating, mental
• confusion, tachycardia, high bounding pulse,
• tremors Later convulsions, coma, shock

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How To Detect Hypoxia Hypercapnia?

• Clinical features
• Blood gas estimation
• Invasive PO2, PCO2, pH
• Noninvasive SaO2
• PtcO2, CO2
• End tidal CO2

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Management

• Management of disease causing respiratory failure
• Management of complications
• Correction of blood gas abnormalities
• Oxygen administration
• Correction of acid-base anomalies
• Assisted respiratory supports

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Oxygen Therapy Indications

• Acute Short term
• Hypoxemia (PaO2 lt 60mmHg)
• Normoxemic hypoxia
• (Low QT, Ac. M.I., Anaemia
• Hypermetabolism, CO poisoning) 
• Chronic Long term
• Ch. Respiratory disease
• Hypoxemia at rest / nocturnal / exertional

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Oxygen Therapy for Acute Hypoxia

1. Correct hypoxia as early as possible
2. Higher concentrations required
3. Maintain (near) normal PaO2
4. May require assisted ventilation
5. Gradually scale down O2 concentrations/ weaning

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COPD Blood Gas Abnormalities

• Hypoxia Ventilation perfusion mismatch
• Hypercapnia and Acidosis
• Airway obstruction
• Alveolar hypoventilation
• Respiratory muscle
  fatigue
• Central hypoventilation
• Hypoxic pulmonary vasoconstriction
• Worsening of pulmonary hypertension

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Oxygen Therapy for COPD

• Acute exacerbation/ Acute (on chronic)
  respiratory failure (Hypercapnic hypoxia)
  Supplemental oxygen
• Chronic respiratory failure- Long term oxygen
  therapy (Domicilliary)

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Oxygen for AE-COPD

• Worsening of hypoxemia Hypercapnia
• Small increase in FiO2 - good response
• However, this can worsen hypercapnia
• CO2 Narcosis
• Release of hypoxic vasoconstriction ? Increased
  dead-space
• Loss of hypoxic respiratory drive
• Haldane effect ? ? CO2 binding capacity

• Venturi mask preferred to a simple mask
• Avoid oxygen-driven nebulization of drugs

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Management of CO2 Narcosis

• Titrate FiO2 by the PaO2 to PAO2 ratio
• Appropriate delivery systems
• Management of hypercapnia
• Non-invasive respiratory support
• Intubation and mechanical ventilation
• Respiratory stimulants
• Clearing secretions/ antibiotic treatment

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Oxygen ToxicitySettings

• ICUs and Acute indications
• Mechanical ventilation
• High FiO2 vs. duration
• Hyperbaric oxygen
• Domiciliary use

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Oxygen Risks

• Physical Fire
• Functional Increased hypoventilation,
  
  Narcosis - High PaCO2
• Cytotoxic damage proliferative and fibrotic
  changes in lungs - ARDS

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Adult (or Acute) Respiratory Distress Syndrome

• Acute respiratory failure, following an acute
  insult / catastrophe (systemic or respiratory),
  in a previously healthy individual, attributable
  to diffuse damage to alveolo-capillary membrane
  resulting in interstitial and alveolar oedema.

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Causes Predisposing Conditions

• Indirect/Systemic
• Septicemia/Endotoxemia
• Severe trauma/shock
• Surface burns
• Pancreatitis
• Stings/bites/anaphylaxis
• Multiple transfusion
• D.I.C./Drugs
• Obstetric shock
• Fat embolism

• Direct
• Aspiration
• Toxic gases
• Respir burns
• Pancreatitis
• Near drowning
• Lung contusion
• Pneumonia
• Pulm. TB
• Oxygen toxicity
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  Others

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Risk Factors

• Diabetes mellitus
• Burns, wounds, multiple trauma
• Immunosuppressives
• Hepatic failure
• Invasive catheters, devices
• Hyposplenism

• Extremes of age
• Malignancy
• Organ transplant
• Radiation therapy
• Renal failure
• Indwelling urine catheter
• A.I.D.S.

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When to Suspect?

• Acute onset of breathlessness
• - Respiratory distress
• Presence of a catastrophe
• No known cardiac or pulmonary illness (?)
• No significant relief with therapy for CHF

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Diagnosis

• Clinical
• Radiological CXR May be normal in first 24
  hrs Later fluffy opacities, prominent
  interstitial lines, consolidations, pulm edema
• Biochemical for systemic organ function
• Investigations for cause of ARDS
• ECG, ECHO or cardiac cath to rule out the
  presence of cardiac edema/ LHF

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Differential Diagnosis

• Pulmonary thromboembolism
• Cardiac pulmonary oedema
• Bronchopneumonia
• Fluid overload / Renal failure
• Neurogenic pulmonary oedema
• Acute Interstitial pneumonia

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Complications

1. Cardiovascular
2. Pulmonary ARDS
3. Neurological
4. Hepatic failure
5. Renal failure
6. Haematological Coagulopathy
7. Others Gastrointestinal, Metabolic

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Management Principles

1. Resuscitation and management of underlying
   condition
2. Oxygenation Respiratory support
3. Fluid electrolytes
4. Nutrition support
5. Specific organ failure management
6. General care
7. Monitoring

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Resuscitation

• Management of shock Fluids, blood, inotropes
• Management of underlying condition
• Drainage/Surgery/Antibiotics/others

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Ventilatory Management

• Avoid alveolar over distension
• Maintain FiO2 lt 0.6
• Use sufficient PEEP to prevent significant tidal
  recruitment derecruitment
• Mode of ventilation is less important
• Tolerate hypercapnia, if necessary
• Weaning Spontaneous breathing trials -
  T-piece, CPAP or PSV. NIV can be used as a
  weaning method

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