SlideShare a Scribd company logo

Hypoxia and its effects

•Download as PPTX, PDF•
•
Dr. Nouman Khan
Dr. Nouman Khan

Hypoxia is a medical condition defined as reduced oxygen availability to tissues. It can be caused by factors that decrease oxygen delivery or utilization at the tissue level. There are four main types of hypoxia: hypoxic (decreased oxygen in arterial blood), anemic (decreased oxygen-carrying capacity of blood), stagnant (decreased blood flow), and histotoxic (inability of tissues to use oxygen). The immediate effects of hypoxia include increased respiration and heart rate, effects on blood including increased red blood cell production, and neurological effects ranging from intoxication to loss of consciousness. Long term effects depend on severity and duration of hypoxic exposure and can include chronic fatigue and irritability.

1 of 31
Download to read offline
Physiology Topic Hypoxia and its effects Compiled by: Dr. Nouman Khan
Reference Book
Hypoxia • Hypoxia is defined as reduced availability of oxygen to the tissues. OR • Hypoxia is a medical term that describes the lack of sufficient oxygen to maintain normal life functions.
Hypoxia • It is also known as – Hypoxiation, – Lack of O2 – Low blood O2 – Oxygen Starvation
Terms Anoxia It is the absence of O2 at tissue level Hypoxia It is the decrease of O2 at the tissue level Although there is adequate blood flow to the tissue
Hypoxia and its effects
Safety considerations • Presence of symptoms depends on the patient’s age, presence of disease process, level of health, and presence of chronic illness. • Consider any underlying causes of hypoxia, such as COPD, heart failure, anemia, and pneumonia, which need to be corrected to prevent and manage hypoxia. • Early signs of hypoxia are anxiety, confusion, and restlessness; if hypoxia is not corrected, hypotension will develop.
Safety considerations • As hypoxia worsens, the patient’s vital signs, activity tolerance, and level of consciousness will decrease. • Late signs of hypoxia include bluish discoloration of the skin and mucous membranes, where vasoconstriction of the peripheral blood vessels or decreased hemoglobin causes cyanosis. Never assume the absence of cyanosis means adequate oxygenation.
CAUSES OF HYPOXIA • Four important factors which leads to hypoxia are: ↓ Velocity of blood flow ↓ Oxygen tension in arterial blood ↓ Utilization of oxygen by the cells. ↓ Oxygen carrying capacity of blood
CLASSIFICATION OF HYPOXIA • On the basis of previous mentioned factors, hypoxia is classified into four types: 1. Hypoxic hypoxia (hypoxemia) 2. Anemic hypoxia 3. Stagnant hypoxia 4. Histotoxic hypoxia.
1. Hypoxic hypoxia (hypoxemia) • Hypoxic hypoxia (Hypoxemia) means decreased oxygen content in blood. • Causes. – ↓ O2 tension in atmospheric air. – ↓ O2 intake due to respiratory disorders. – ↓ O2 diffusion due to respiratory disorders. – ↓ blood pumping due to cardiac disorders e.g. congestive heart failure.
2. Anemic Hypoxia • Anemic hypoxia is the condition characterized by the inability of blood to carry enough amount of oxygen. • Oxygen availability is normal. • But the blood is not able to take up sufficient amount of oxygen due to anemic condition.
Causes for anemic hypoxia • Anemic hypoxia is caused by the following conditions: Formation of altered Hb ↓ No. RBCs Combination of Hb with gases other than O2 & CO2 ↓ Hb content in the blood
1. ↓ No. RBCs Hemorrhage bone marrow diseases e.g Aplastic anemia
• Conditions which decrease the RBC count or change the structure, shape and size of RBC. 2.↓ Hb content in the blood
iii. Formation of altered hemoglobin Poisoning Methemoglobin cannot combine with oxygen chlorates, nitrates, ferricyanides, iron into ferric form Turns hemoglobin into methemoglobin Thus Hb quaility is ↓ for O2
Combination of Hb with gases other than O2 & CO2 • When hemoglobin combines with – Carbon monoxide. – Hydrogen sulfide. – Nitrous oxide. • It looses the capacity to transport oxygen
3. Stagnant Hypoxia • It is the hypoxia caused by decreased velocity of blood flow. It is otherwise called hypokinetic hypoxia. Causes for stagnant hypoxia It can be 1. General stagnant hypoxia 2. Local Stagnant Hypoxia
Causes for stagnant hypoxia General Stagnant Hypoxia it may result from heart disease that impairs the circulation, impairment of venous return of blood, or trauma that induces shock. Local stagnant hypoxia It may be due to any condition that reduces or prevents the circulation of the blood in any area of the body. Examples include Raynaud syndrome and Buerger disease, which restrict circulation in the extremities.
Hypoxia and its effects
Poisoning even if oxygen is supplied cyanide or sulfide Destroys the cellular oxidative enzymes As a result complete paralysis of cytochrome oxidase system the tissues are not in a position to utilize it. Histotoxic hypoxia 4. Histotoxic Hypoxia
Characteristic features of different types of hypoxia Features Hypoxic hypoxia Anemic hypoxia Stagnant hypoxia Histotoxic hypoxia Po2 in Arterial blood ↓ Normal Normal Normal O2 carrying capacity of blood Normal ↓ Normal Normal Velocity of blood flow Normal Normal ↓ Normal Utilization of O2 by tissue Normal Normal Normal ↓ Efficacy of O2 therapy 100% 75 % < 50% Not useful
Effects of Hypoxia Effects of hypoxia are of two types: 1. Immediate effects i. Effects on blood ii. Effects on cardiovascular system iii. Effects on respiration iv. Effects on digestive system v. Effects on central nervous system 2. Delayed effects.
1. Immediate effects i. Effects on blood secretion of erythropoietin increases production of RBC increases the oxygen carrying capacity of blood Hypoxia
1. Immediate effects ii. Effects on cardiovascular system ↑ cardiac output ↑ rate and contraction force of heart ↑ blood pressure Due to cardiac & vasomotor center reflex Later, there is reduction in ALL these factor.
1. Immediate effects iii. Effects on respiration Located at carotid bodies Moniters O2 level (Below 60mm hg) ↑ Respiratory Rate Chemoreceptor Washes out large amount of CO2. Causes Alkalemia At the end it become reduced.
1. Immediate effects iv. Effects on digestive system • It is associated with – loss of appetite, – nausea and – vomiting. – Mouth becomes dry (Xerostomia) – Thirst feeling.
1. Immediate effects v. Effects on central nervous system • In mild hypoxia, the symptoms are similar to those of alcoholic intoxication.
V. Effects on central nervous system Depresse d Apathetic with general loss of self control loss of discriminative ability Quarrelsome lack of coordination Disorientation ill-tempered and rude Talkative Memory is impaired If hypoxia is acute and severe, there is a sudden loss of consciousness. If not treated immediately, coma occurs, which leads to death
2. Delayed effects • Delayed effects appear depending upon the – length – severity of the exposure to hypoxia. • The person becomes highly irritable and Develops the symptoms of mountain sickness such as; – nausea, – vomiting, – depression, – weakness and fatigue.
Hypoxia and its effects

More Related Content

Hypoxia and its effects

  • 1. Physiology Topic Hypoxia and its effects Compiled by: Dr. Nouman Khan
  • 3. Hypoxia • Hypoxia is defined as reduced availability of oxygen to the tissues. OR • Hypoxia is a medical term that describes the lack of sufficient oxygen to maintain normal life functions.
  • 4. Hypoxia • It is also known as – Hypoxiation, – Lack of O2 – Low blood O2 – Oxygen Starvation
  • 5. Terms Anoxia It is the absence of O2 at tissue level Hypoxia It is the decrease of O2 at the tissue level Although there is adequate blood flow to the tissue
  • 7. Safety considerations • Presence of symptoms depends on the patient’s age, presence of disease process, level of health, and presence of chronic illness. • Consider any underlying causes of hypoxia, such as COPD, heart failure, anemia, and pneumonia, which need to be corrected to prevent and manage hypoxia. • Early signs of hypoxia are anxiety, confusion, and restlessness; if hypoxia is not corrected, hypotension will develop.
  • 8. Safety considerations • As hypoxia worsens, the patient’s vital signs, activity tolerance, and level of consciousness will decrease. • Late signs of hypoxia include bluish discoloration of the skin and mucous membranes, where vasoconstriction of the peripheral blood vessels or decreased hemoglobin causes cyanosis. Never assume the absence of cyanosis means adequate oxygenation.
  • 9. CAUSES OF HYPOXIA • Four important factors which leads to hypoxia are: ↓ Velocity of blood flow ↓ Oxygen tension in arterial blood ↓ Utilization of oxygen by the cells. ↓ Oxygen carrying capacity of blood
  • 10. CLASSIFICATION OF HYPOXIA • On the basis of previous mentioned factors, hypoxia is classified into four types: 1. Hypoxic hypoxia (hypoxemia) 2. Anemic hypoxia 3. Stagnant hypoxia 4. Histotoxic hypoxia.
  • 11. 1. Hypoxic hypoxia (hypoxemia) • Hypoxic hypoxia (Hypoxemia) means decreased oxygen content in blood. • Causes. – ↓ O2 tension in atmospheric air. – ↓ O2 intake due to respiratory disorders. – ↓ O2 diffusion due to respiratory disorders. – ↓ blood pumping due to cardiac disorders e.g. congestive heart failure.
  • 12. 2. Anemic Hypoxia • Anemic hypoxia is the condition characterized by the inability of blood to carry enough amount of oxygen. • Oxygen availability is normal. • But the blood is not able to take up sufficient amount of oxygen due to anemic condition.
  • 13. Causes for anemic hypoxia • Anemic hypoxia is caused by the following conditions: Formation of altered Hb ↓ No. RBCs Combination of Hb with gases other than O2 & CO2 ↓ Hb content in the blood
  • 14. 1. ↓ No. RBCs Hemorrhage bone marrow diseases e.g Aplastic anemia
  • 15. • Conditions which decrease the RBC count or change the structure, shape and size of RBC. 2.↓ Hb content in the blood
  • 16. iii. Formation of altered hemoglobin Poisoning Methemoglobin cannot combine with oxygen chlorates, nitrates, ferricyanides, iron into ferric form Turns hemoglobin into methemoglobin Thus Hb quaility is ↓ for O2
  • 17. Combination of Hb with gases other than O2 & CO2 • When hemoglobin combines with – Carbon monoxide. – Hydrogen sulfide. – Nitrous oxide. • It looses the capacity to transport oxygen
  • 18. 3. Stagnant Hypoxia • It is the hypoxia caused by decreased velocity of blood flow. It is otherwise called hypokinetic hypoxia. Causes for stagnant hypoxia It can be 1. General stagnant hypoxia 2. Local Stagnant Hypoxia
  • 19. Causes for stagnant hypoxia General Stagnant Hypoxia it may result from heart disease that impairs the circulation, impairment of venous return of blood, or trauma that induces shock. Local stagnant hypoxia It may be due to any condition that reduces or prevents the circulation of the blood in any area of the body. Examples include Raynaud syndrome and Buerger disease, which restrict circulation in the extremities.
  • 21. Poisoning even if oxygen is supplied cyanide or sulfide Destroys the cellular oxidative enzymes As a result complete paralysis of cytochrome oxidase system the tissues are not in a position to utilize it. Histotoxic hypoxia 4. Histotoxic Hypoxia
  • 22. Characteristic features of different types of hypoxia Features Hypoxic hypoxia Anemic hypoxia Stagnant hypoxia Histotoxic hypoxia Po2 in Arterial blood ↓ Normal Normal Normal O2 carrying capacity of blood Normal ↓ Normal Normal Velocity of blood flow Normal Normal ↓ Normal Utilization of O2 by tissue Normal Normal Normal ↓ Efficacy of O2 therapy 100% 75 % < 50% Not useful
  • 23. Effects of Hypoxia Effects of hypoxia are of two types: 1. Immediate effects i. Effects on blood ii. Effects on cardiovascular system iii. Effects on respiration iv. Effects on digestive system v. Effects on central nervous system 2. Delayed effects.
  • 24. 1. Immediate effects i. Effects on blood secretion of erythropoietin increases production of RBC increases the oxygen carrying capacity of blood Hypoxia
  • 25. 1. Immediate effects ii. Effects on cardiovascular system ↑ cardiac output ↑ rate and contraction force of heart ↑ blood pressure Due to cardiac & vasomotor center reflex Later, there is reduction in ALL these factor.
  • 26. 1. Immediate effects iii. Effects on respiration Located at carotid bodies Moniters O2 level (Below 60mm hg) ↑ Respiratory Rate Chemoreceptor Washes out large amount of CO2. Causes Alkalemia At the end it become reduced.
  • 27. 1. Immediate effects iv. Effects on digestive system • It is associated with – loss of appetite, – nausea and – vomiting. – Mouth becomes dry (Xerostomia) – Thirst feeling.
  • 28. 1. Immediate effects v. Effects on central nervous system • In mild hypoxia, the symptoms are similar to those of alcoholic intoxication.
  • 29. V. Effects on central nervous system Depresse d Apathetic with general loss of self control loss of discriminative ability Quarrelsome lack of coordination Disorientation ill-tempered and rude Talkative Memory is impaired If hypoxia is acute and severe, there is a sudden loss of consciousness. If not treated immediately, coma occurs, which leads to death
  • 30. 2. Delayed effects • Delayed effects appear depending upon the – length – severity of the exposure to hypoxia. • The person becomes highly irritable and Develops the symptoms of mountain sickness such as; – nausea, – vomiting, – depression, – weakness and fatigue.