Post operative hypoxia

Post operative hypoxia is caused by several factors :

I. General—patient’s factors

Exaggerated preoperative problems such as:

• Extreme obesity

• Geriatric age

• Pre-existing cardiopulmonary disease

2. Diminished inspired oxygen

• Lack of oxygen supplementation devices

• Excessive suctioning

• Diffusion hypoxia after nitrous oxide

3. Impaired ventilatory inefficiency

• Obstructed upper airway due to tongue fall, large uvula, laryngeal spasm, vocal cord palsy, tracheal collapse is one factor that leads to Post operative hypoxia

• Obstructed lower airway due to:

– Secretions

– Bronchospasm

– Atelectasis

• Muscular weakness

• Pharmacological causes

– Residual effects of respiratory depressant drugs such as anaesthetic agents, narcotic analgesics, neuromuscular blocking agents. The other factors that cause Post operative hypoxia are :

• Surgical factors such as binders or type of incision

• Postoperative pain

• Excessive analgesics medication postoperatively

4. Abnormal ventilation

• Exaggerated shunting

• Loss of sigh mechanism

• Increased dead space

5. Deficient oxygen loading

6. Diminished transport

• Extension of preoperative factors

• Continuation of uncorrected surgical factors

7. Cardiovascular instability

• Uncorrected acid-base abnormalities

• Fluid and electrolyte imbalance

• Cardiac depression due to drugs or acidosis

8. Impaired tissue delivery is yet another cause for Post operative hypoxia

• Capillary stasis

• Loss of tissue perfusion

• Excess or non removal of tissue lactate

• Cellular drug effects