Abnormal Types of Breathing, Hypoxia, Cyanosis, Asphyxia

Abnormal type of breathings

1. ABNORMAL TYPES OF RESPIRATION 30.05.19

2. PERIODIC BREATHING Cheyne Stokes Breathing Biot Breathing

3. Cheyne Stokes Breathing There are alternate periods of hyperventilation and apnea. Transition from one period to the other is gradual. This type of breathing is seen in cardiac failure, uremia, at high altitude , after a period of hyperventilation and also in morphine poisoning

4. Mechanism of Cheyne Stoke Breathing W hen a person hyperventilates, there is increased washout of CO2 and there is decreased PCO2 in arterial blood. This will inhibit the respiratory center so there is period of apnea . So CO2 accumulates which will then stimulate the respiratory centre causing hyperventilation .

5. Mechanism of Cheyne Stoke Breathing When there is cardiac failure, there is prolonged circulation time between the lungs and the brain . During cardiac failure, there is low cardiac output, sluggish blood flow so blood takes longer time to pass from the lungs to brain. So the effect of CO2 on respiratory center is delayed which inhibits the respiratory center to produce apnea. When there is apnea CO2 accumulates in the blood which then stimulates the respiratory center causing hyperventilation.

6. Biot Breathing There are alternate periods of hyperventilation and apnea but there is abrupt transition from one period to the other. It is seen in meningitis and diseases of medulla oblongata.

7. Sleep Apnea Obstructive Sleep Apnea Central Sleep Apnea

8. HYPOXIA

9. Hypoxia Decreased availability of oxygen to the tissues. There are 4 types of Hypoxia Arterial or hypoxic Hypoxia Anemic Hypoxia Ischemic or Stagnant Hypoxia Histotoxic Hypoxia

10. Arterial or Hypoxic Hypoxia Arterial PO2 is decreased in this hypoxia, so there is decreased binding of O2 with Hb so supply of oxygen to tissues is decreased. Causes: High altitude, low PO2 in atmospheric air Depression of respiratory centre such as in morphine poisoning Weakness or paralysis of respiratory muscles Atelactasis , bronchial asthma, pneumothorax , pleural effusion, pulmonary fibrosis Congenital heart diseases.

11. Arterial or Hypoxic Hypoxia As arterial PO2 is low, respiratory centre is stimulated but in most cases there is respiratory disease so no hyperventilation. However impulses also go to the vasomotor centre from peripheral chemoreceptors because of low PO2, which increases heart rate Cardiac output. Erythropoietin secretion is also stimulated causing secondary polycythemia . As there is low PO2 in the blood flowing through lungs which causes vasoconstriction of blood vessels in lungs causing pulmonary hypertension and thus right heart failure.

12. Anemic Hypoxia It is because of decreased oxygen carrying capacity of blood, arterial PO2 is normal. Causes: Anemia: Less Hb is present to transport oxygen Abnormal types of Hb present i.e. HbS . Over dosage of Nitrates, perchlorate which produce methemoglobin

13. Anemic Hypoxia Binding sites for O2 in Hb are not available such as in CO poisoning. Hb has 250 times more affinity to bind CO as compared to O2. CO poisoning leads to formation of Carbon monoxy Hb which shifts the oxygen Hb dissociation curve to left side. CO is also toxic to the cytochromes . In this poisoning as arterial PO2 is normal, respiratory centre cannot be stimulated. Symptoms of this poisoning include cherry red color of skin and mucus membrane, headache, nausea, vomiting. Treatment includes removal of patient from the source of CO and then we give O2 even Hyperbaric O2.

14. Stagnant or Ischemic Hypoxia It is due to sluggish or inadequate blood flow to tissue. Arterial PO2 and oxygen carrying capacity of Hb is normal . Causes: Decreased Cardiac output due to cardiac failure Shock Hypovolemia Blood remains in tissues for longer time and they extract more O2 from blood but this is not sufficient for their requirements. There is increased arteriovenous concentration of blood.

15. Histotoxic Hypoxia It is due to inability of the tissues to utilize oxygen. It is due to inhibition of oxidative processes . There is normal arterial PO2, oxygen carrying capacity of Hb and Blood flow. Cyanide poisoning which inhibits the cytochrome which leads to inhibition of oxidative processes. Treatment is we give methylene blue or nitrates which convert Hb into Met Hb which in turn binds with Cyanide to form cyanmet Hb which is non toxic. Over dosage of narcotics which inhibits the enzyme dehydrogenase , to inhibit oxidative processes. Beri beri where there is deficiency of thiamine which also acts as a coenzyme in many reactions.

16. ASPHYXIA

17. ASPHYXIA Simultaneous hypoxia and hypercapnia . It is seen when there is acute airway obstruction such as in strangulation or when a person is forced to rebreathe his own expired air . Whenever there is asphyxia, there is strong stimulation of respiratory centre . Heart rate and Blood pressure increases . Increased secretion of catecholamines from adrenal medulla . If asphyxia continues respiration becomes slow, there is unconsciousness, convulsions and death occurs.

18. CYANOSIS

19. Cyanosis C yanosis means blueness of the skin C ause is excessive amounts of deoxygenated hemoglobin in the skin blood vessels, especially in the capillaries. This deoxygenated hemoglobin has an intense dark blue-purple color that is transmitted through the skin. Definite cyanosis appears whenever the arterial blood contains more than 5 grams of deoxygenated hemoglobin in each 100 milliliters of blood. A person with anemia almost never becomes cyanotic because there is not enough hemoglobin for 5 grams to be deoxygenated in 100 milliliters of arterial blood. In a person with excess red blood cells, as occurs in polycythemia vera , the great excess of available hemoglobin that can become deoxygenated leads frequently to cyanosis, even under otherwise normal conditions.