Hypoxia & hypoxemia

AWARENESS

1. HYPOXIA & HYPOXEMIA Imdad gul Ipms,kmu

2. Hypoxia,  condition of the body in which the tissues are starved of  oxygen . In its extreme form, where oxygen is entirely absent, the condition is called  anoxia . There are four types of hypoxia: (1)   H ypoxemic  type, in which the oxygen  pressure  in the blood going to the tissues is too low to saturate the  hemoglobin ; (2)  Anemic type, in which the amount of functional hemoglobin is too small, and hence the capacity of the blood to carry oxygen is too low; (3) S tagnant type, in which the blood is or may be normal but the flow of blood to the tissues is reduced or unevenly distributed; and (4)   H istotoxic type, in which the  tissue  cells are poisoned and are therefore unable to make proper use of oxygen. Diseases of the blood, the heart and circulation, and the lungs may all produce some form of hypoxia. DIFFINATION

3. The hypoxemic type of hypoxia is due to one of two mechanisms: (1) a decrease in the amount of breathable oxygen—often encountered in pilots, mountain climbers, and people living at high altitudes—due to the reduced  barometric pressure  ( see   altitude sickness ), or (2) cardiopulmonary failure in which the lungs are unable to efficiently transfer oxygen from the alveoli to the blood 1-HYPOXEMIC HYPOXIA

4. In the case of anemic hypoxia, either the total amount of hemoglobin is too small to supply the body’s oxygen needs, as in  anemia  or after severe bleeding, or hemoglobin that is present is rendered nonfunctional. Examples of the latter case are  carbon monoxide poisoning  and  metho-globinuria , in both of which the hemoglobin is so altered by toxic agents that it becomes unavailable for oxygen transport, and thus of no respiratory value. 2-ANEMIC HYPOXIA

5. Stagnant hypoxia, in which blood flow through the capillaries is insufficient to supply the tissues, may be general or local. If general, it may result from  heart disease  that impairs the circulation, impairment of veinous return of blood, or trauma that induces shock. Local stagnant hypoxia may be due to any condition that reduces or prevents the circulation of the blood in any area of the body. Examples include  Raynaud’s disease  and  Buerger’s disease , which restrict circulation in the extremities; the application of a tourniquet to control bleeding; ergot poisoning; exposure to cold; and overwhelming systemic infection with shock. 3-STAGNANT HYPOXIA

6. In histotoxic hypoxia the cells of the body are unable to use the oxygen, although the amount in the blood may be normal and under normal tension. Although characteristically produced by cyanide, any agent that decreases  cellular respiration  may cause it. Some of these agents are narcotics, alcohol, formaldehyde, acetone, and certain anesthetic agents. 4-HISTOTIC HYPOXIA

7. Hypoxemia is an inadequate partial pressure of oxygen in arterial blood. Hypoxemia has many causes, often  respiratory disorders , and can cause tissue  hypoxia  as the blood is not supplying enough oxygen to the body . extreme hypoxia can be called anoxia, extreme hypoxemia can be called anoxemia HYPOXEMIA

8. Hypoxemia is usually defined in terms of reduced  partial pressure  of oxygen (mm Hg) in arterial blood  when the partial pressure of oxygen in blood is less than 60 mm Hg, when hemoglobin  oxygen saturation  is less than 90% Hypoxemia  refers to low oxygen in the blood, and the more general term  hypoxia  is an abnormally low oxygen content in any tissue or organ, or the body as a whole.Hypoxemia can cause  hypoxia  (hypoxemic hypoxia), but hypoxia can also occur via other mechanisms, such as  anemia

9. There are 5 phyiological causes of HYPOXEMIA HIGH ALTITUDE DIFFUSION HYPOVENTILATION SHUNTING VENTILATION-PERFUSION MISMATCH PHYSIOLOGICAL CAUSES

10. causes

11. Equipment oxygen supply,flowmeter,breathing system,ventilator failure,tracheal tube Hypoventilation respiratory depression,obstruction Ventilation perfusion mismatch bronchial intubation,secretions,atelectasis,pneumothorax,bronchospasm,pulmonary oedema , and embplus,loa cardiac output Malignant hyperthermia Causes of hypoxemia during anesthesia

12. USE OF PULSE OXIMETER FOR EARLY DETECTION DESATURATION CHECK A-B-C INCREASE INSPIRED OXYGEN CETURATION BY 100% CHECK THE INTEGRITY OF THE BREATHING SYSTEM BY MANUAL VENTILATION OF THE LUNGS CONFIRM THE POSITION AND POTENCY OF THE TUBE CHECK BILATERAL CHEST MOVEMENT AND BREATHING SOUNDS PEEP FOR GENTLE LUNG HYPERINFLATION MEASURE AND STABLIZE CORE TEMPRATURE MANAGMENT

13. v/Q mismatch is the most common cause of hypoxemia 100% oxygen responds in high altitude,diffusion,hypoventilation,and v/Q mismatch but not in shunting. REMEMBER

14. THANKS ……………………………………….