RESPIRATORY FAILURE.failure of gas exchange

Respiratory failure

1. BASICS OF RESPIRATORY
FAILURE
BY
MUTEGEKI ADOLF

2. Definition
•Respiratory failure occurs when the respiratory
system fails to maintain adequate gas exchange,
resulting in hypoxia (low oxygen levels),
hypercapnia(elevated carbon dioxide levels), or
both.
•It can be classified into Type I (hypoxemic) and
Type II (hypercapnic) respiratory failure.

3. •The inability of the respiratory system to
adequately oxygenate the blood withor withouta
concurrent alteration in carbon dioxide
elimination.
•It can be acuteor Chronicdepending on the
cause.
•Acute
eg: drug overdose, pneumonia, pneumothorax
•Chronic
eg: severe COPD

4. TYPES
•Type I
hypoxemic respiratory failure
•Type II
hypercapneicrespiratory failure
•Type III
perioperative respiratory failure

5. Type I -Hypoxemic Failure
•Oxygenation failure
•PaO
2< 60 mmHg OR < 8 kpa
•PaCO
2normal or < 35 mmHg
•pH normal or elevated
•ventilation (V
A) and perfusion (Q) mismatching is the most
commoncause of hypoxemia.
•Either by increasing the dead space or by wasted
ventilation

6. Type II (HypercapnicRespiratory Failure)
•Ventilation failure
•PaO
2< 60 mmHg
•PaCO
2> 45 mmHg OR >6.7 kpa
•pH < 7.35

7. Aetiology
•Type I (Hypoxemic Respiratory Failure):
•Pneumonia
•Pulmonary Edema:Fluid accumulation in the lungs due to
heart failure or acute respiratory distress syndrome
(ARDS).
•Pulmonary Embolism
•Interstitial Lung Disease:Diseases causing scarring and
inflammation of lung tissue.
•Acute Respiratory Distress Syndrome (ARDS):Severe
inflammation and fluid buildup in the alveoli.

8. COPD
Asthma
Pneumothorax
Pulmonary fibrosis
Obesity
Lymphatic
carcinamatosis
Pnueumoconiosis
Granulomatous lung
disease
Cyanotic congheart
disease
Bronchiectasis
Crush lung injury
FAT embolism

9. Type II (HypercapnicRespiratory Failure)
COPD
Asthma
Drug overdose/Poisoning
Myasthenia gravis
Polyneuropathy
Poliomyelitis
Myopathy,Porphyria
Head/ cervical cord injury
•Primary alveolar hypoventilation
•Sleep apnoeasyndrome
•Pulmonary edema
•ARDS
•Myxedema
•Laryngeal edema
•Tetanus
•Foreign body

10. Type III (perioperative respiratory failure)
•Perioperative respiratory failure, also known as Type III
respiratory failure, is a condition that occurs in the
perioperative period (around the time of surgery) due to
complications arising from anesthesia, surgery, or the
underlying health status of the patient.
•This type of respiratory failure is often associated with
atelectasis (collapse of lung tissue) and is commonly seen in
patients undergoing major surgeries, especially abdominal
or thoracic procedures.

11. Causes of type III
•Atelectasis
•Aspiration
•Pulmonary Edema
•Pneumonia
•Pulmonary Embolism
•Airway Obstruction
•Hypoventilation: Due to
the effects of
anesthetics, sedatives, or
neuromuscular blockers.
•Acute Respiratory
Distress Syndrome
(ARDS): Severe
inflammation and lung
injury postoperatively.

12. Pathophysiology

15. Pathophysiology
Hypoxemic Respiratory Failure (Type I):
•Impaired Diffusion:Due to thickening or damage to the
alveolar-capillary membrane (e.g., interstitial lung
disease).
•Ventilation-Perfusion Mismatch:Areas of the lung
receive oxygen but not enough blood flow (or vice versa),
common in pulmonary embolism and pneumonia.
•Shunt:Blood bypasses ventilated areas of the lung,
leading to unoxygenatedblood circulating through the
body.

16. HypercapnicRespiratory Failure (Type II):
•Alveolar Hypoventilation:Due to airway
obstruction, respiratory muscle fatigue, or
reduced respiratory drive.
•Increased CO2 Production:Often secondary to
increased metabolic demand or fever.
•Reduced CO2 Clearance:Seen in COPD where
there is obstruction to airflow.

17. Type III (perioperative respiratory failure)
•Reduced Functional Residual Capacity (FRC): Anesthesia
and supine positioning reduce FRC, making the lungs more
prone to collapse.
•Impaired Ventilation-Perfusion (V/Q) Matching: Collapsed
alveoli lead to areas of the lung being perfused but not
ventilated (shunt), causing hypoxemia.
•Impaired Gas Exchange: With alveolar collapse and fluid
accumulation, the surface area for gas exchange is reduced,
leading to hypoxemia and hypercapnia.
•Decreased Respiratory Muscle Function: Pain, sedation,
and muscle relaxants impair the ability to take deep breaths or
cough effectively.

18. Clinical Presentations
•Hypoxemia Symptoms:Dyspnea (shortness of breath),
cyanosis, restlessness, confusion, tachypnea (rapid
breathing).
•HypercapniaSymptoms:Dyspnea, headache, confusion,
lethargy, asterixis(flapping tremor), and in severe cases,
coma.
•General Symptoms:Tachycardia, hypertension, use of
accessory muscles for breathing, nasal flaring, and
diaphoresis (sweating).

19. Investigations
•Arterial Blood Gas (ABG) Analysis:Key investigation to confirm
respiratory failure, showing hypoxemia, hypercapnia, or both.
•Chest X-ray:To identify causes such as pneumonia, pulmonary edema,
or pneumothorax.
•Pulmonary Function Tests:Useful in chronic respiratory conditions
like COPD.
•CT Scan of the Chest:Detailed imaging for interstitial lung disease,
pulmonary embolism, or lung masses.
•Blood Tests:Complete blood count (CBC), electrolytes, and
biomarkers (e.g., BNP for heart failure).
•Electrocardiogram (ECG) and Echocardiogram:To assess cardiac
function, especially in cases of pulmonary edema.

20. Management
Oxygen Therapy:
•Low-Flow Systems:Nasal cannula or simple
masks for mild hypoxemia.
•High-Flow Systems or Non-RebreatherMask:
For moderate to severe hypoxemia.
•Mechanical Ventilation:Invasive (intubation) or
non-invasive (CPAP/BiPAP) for severe cases or
hypercapnia.

21. Treat Underlying Cause:
•Antibiotics:For pneumonia or sepsis.
•Diuretics:For pulmonary edema due to heart
failure.
•Bronchodilators and Steroids:For asthma or
COPD exacerbations.
•Anticoagulation:For pulmonary embolism.
•VentilatorySupport:Invasive ventilation if
respiratory muscle fatigue or severe
hypoventilation occurs.

22. Supportive Care:
•Fluids and Nutrition:Manage fluid balance
and provide nutritional support.
•Physiotherapy:To aid with secretion
clearance and improve ventilation.

23. Prognosis
•Best predictor of mortality in patients with acute on
chronic respiratory failure is degree of acidemia.
•pH< 7.26 is associated with higher mortality.
•Long term mortality of patients who survive an
episode of acute respiratory failure depends on
underlying illness.
Eg: COPD, 50% survival at end of 3 years

24. Prevention
•Smoking Cessation:To reduce the risk of COPD and lung
cancer.
•Vaccinations:Influenza and pneumococcal vaccines to
prevent respiratory infections.
•Management of Chronic Conditions:Proper management
of asthma, COPD, heart failure, and diabetes.
•Avoidance of Respiratory Depressants:Careful use of
sedatives and opioids in at-risk patients.
•Regular Monitoring:For patients with neuromuscular
disorders or at risk of respiratory failure