OXYGEN THERAPY,

1. Definition
• Respiratory failure results from a disorder
in which lung function is inadequate for the
metabolic requirements of the individuals.
• Pao2 <8 kpa (60 mm Hg)
• Paco2 <6.6 kpa/ >6.6 kpa(45 mm Hg)

2. Effects of hypoxia
and hypercarbia
• Hypoxia-
• Headache, drowsiness, irritability,
confusion, coma
• Cellular- necrosis, edema, haemorrhage.
• Hypercarbia-
• hyperventillation
• Headache, warm extremities,tremors,
flushing,confusion,drowsiness,coma.

3. Types of respiratory failure
• 1.Acute : A sudden catastrophic event leads to
life threatening respiratory insufficiency. eg-
inhaled F.B.,flail chest.
• 2.Chronic : Gradual worsening of respiratory
function leading to progressive impairement of
gas exchange. eg-COPD. In these patients,even
a mild insults (infection) can precipitate acute on
chronic respiratory failure.

4. Types of respiratory failure
• Type1or acute hypoxemic R. F. - Usually
results from condition in which there is defective
diffusion but the ventillation is normal.
• CAUSES:
• Pulmonary edema(heart failure,acute lung
injury,intravascular volume overload)
• pulmonary embolism
• pneumonia
• Severe acute asthma

5. Types of respiratory failure con…
• Type 2 respiratory failure - Occurs as a
result of alveolar hypoventillation and
results in the inability to eliminate co2
effectively.
• Causes:
• 1. Impaired CNS drive to breathe -
• drug overdose, brainstem injury,
• Hypothyroidism, sleep apnoea syndrome

6. Types of respiratory failure con…
• 2. Impaired strength of respiratory muscle -
• Myasthenia gravis, G.B. syndrome, phrenic
nerve injury, myopathy, electrolyte
derangements.
• 3.Increased loads on respiratory system -
• Broncospasm, inhaled F.B.
• Reduced chest wall compliance (pleural
effusion, pneumothorax, flail chest )
• Reduced lung compliance (alveolar edema,
atelectasis )

7. Types of respiratory failure con…
• Type 3 respiratory failure:
• Occurs as a result of lung atelectasis.
• Also called perioperative R.F.as most
commonly occurs in perioperative
period,due to decrease in F.R.C. after
G.A., leading to collapse of dependent
lung units.

8. Types of respiratory failure con…
• Such atelectasiscan be treated by frequent
changes in position,chest physiotherapy,
upright positioning and control of incisional
pain.
• TYPE 4 RESPIRATORY FAILURE:
• occurs due to hypo-perfusion of
respiratory muscles in patients in shock.

9. Management
• 1.Maintenance of airway
• Removal of foreign body,secretion
• Chin lift and head tilt position
• Tracheostomy
• 2.Correction of hypoxia
• Supply of oxygen with nasal prongs,face/nasal /venturi
mask
• High concentration of oxygen(>35%in acute condition)
• Controlled low conc oxygen(<24% in chronic condition)

10. Management cont…
• 3.Assistance to ventillation (mechanical ventillation)
• 4.Treatment of the underlying cause
• Fixation of flail chest
• reversal of narcotic drugs.
• 5.supportive measures
• Nutrition
• Fluid and electrolyte balance
• Physiotherapy

11. Management cont…
• 6. Drugs
• Antibiotics(as infection is common and
precipitating factor ).
• Analgesics (flail chest, post operative pain)
• Diuretics
• Bronchodilators
• Corticosteroides