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بسم الله الرحمن الرحيم

بسم الله الرحمن الرحيم. ﴿و ما أوتيتم من العلم إلا قليلا﴾. صدق الله العظيم الاسراء اية 58. Haemorrhage. By Dr. Abdel Aziz M. Hussein Lecturer of Medical Physiology Member of American Society of Physiology. Haemorrhage. Haemorrhage. ◊ Def, It means loss of blood from the CVS. ◊ Types:

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بسم الله الرحمن الرحيم

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  1. بسم الله الرحمن الرحيم ﴿و ما أوتيتم من العلم إلا قليلا﴾ صدق الله العظيم الاسراء اية 58 Dr abdelaziz Hussein, Mansoura Faculty of Medicine

  2. Haemorrhage By Dr. Abdel Aziz M. Hussein Lecturer of Medical Physiology Member of American Society of Physiology Dr abdelaziz Hussein, Mansoura Faculty of Medicine

  3. Haemorrhage Dr abdelaziz Hussein, Mansoura Faculty of Medicine

  4. Haemorrhage ◊ Def, • It means loss of blood from the CVS. ◊ Types: • i) According to Site of bleeding: • External (revealed) e.g. bleeding from open wound. • Internal (concealed) e.g. intra-abdominal, intrathoracic, intracranial....etc. Dr abdelaziz Hussein, Mansoura Faculty of Medicine

  5. Haemorrhage ◊ Types: ii) According to the amount of blood loss: • Mild →loss of few cc. • Moderate → loss up to 20-30%. • Severe → loss more than 30% • Loos of less than 20% is compensated by physiological mechanisms, while loss of more than 20% is aided by blood transfusion iii) According to the rate of blood loss: • Acute → sudden loss of blood. • Chronic → repeated bleeding over a long period of time e.g. from piles, parasitic infestation. • Acute blood loss of large amount of blood is more dangerous than chronic bleeding. Dr abdelaziz Hussein, Mansoura Faculty of Medicine

  6. Haemorrhage ◊ Types: iv) According to Source: • The rate of blood loss depends on the injured vessels, it may be: • Arterial→ bleeding from injured artery. • Venous→ bleeding from injured vein. • Capillaries→ bleeding from eroded or burned skin surface. • Sinusoidal→ As in uterine bleeding. Dr abdelaziz Hussein, Mansoura Faculty of Medicine

  7. Haemorrhage ◊ Manifestations of haemorrhage: • ↓ed ABP. • The pulse is rapid, weak and feeble • Respiration is rapid, but the depth of respiration is at first deep then shallow. • The cutaneous veins are collapsed and fill slowly when compressed centrally. • The skin is pale, cold, moist, and slightly cyanotic. • Oliguria. • Fainting may occur. Dr abdelaziz Hussein, Mansoura Faculty of Medicine

  8. Compensatory Changes during Haemorrhage Dr abdelaziz Hussein, Mansoura Faculty of Medicine

  9. Haemorrhage • Haemorrhage has 2 effects; Dr abdelaziz Hussein, Mansoura Faculty of Medicine

  10. Immediate Compensatory Changes Dr abdelaziz Hussein, Mansoura Faculty of Medicine

  11. CVS changes Dr abdelaziz Hussein, Mansoura Faculty of Medicine

  12. CVS changes a. Cardiac acceleration: ◊ Causes:↑ed heart rate may be due to; • ↓ed ABP, ↑es heart rate by Mary's law. • ↑ed adrenaline secretion stimulates SAN directly. • Hypoxia in haemorrhage stimulates CAC directly. ◊ Significance: • It ↑es the diastolic BP and the mean systemic BP→ maintains the blood flow through the cerebral and coronary blood vessels. Dr abdelaziz Hussein, Mansoura Faculty of Medicine

  13. CVS changes • b. ↑ed vasoconstrictor discharges: ◊ Site of VC • It causes generalized VC except in the cerebral and coronary vessels. • VC of the skin → cold & pale skin. • VC of the kidney vessels→ oliguria or even anuria. • Cerebral arterioles are not constricted because their VC innervation is functionally insignificant. • Coronary arteries are dilated due to accumulated metabolites. Dr abdelaziz Hussein, Mansoura Faculty of Medicine

  14. CVS changes • b. ↑ed vasoconstrictor discharges: ◊ Causes of VC: • ↑ed secretion of epinephrine and norepinephrine. • ↓ed depressor impulses from the arterial baroreceptors. • ↓ed VR leads to reflex VC of the arterioles and venules (McDowalَ s reflex). • ↑ed secretion of vasopressin. • Release of serotonin from platelets. • Renal ischemia leads finally to VC by angiotensin II. Dr abdelaziz Hussein, Mansoura Faculty of Medicine

  15. CVS changes b. ↑ed vasoconstrictor discharges: ◊ Importance of VC: • helps the VR and maintains the cardiac filling, COP and ABP. c) Contraction of blood reservoirs: ◊ Importance: • Blood reservoirs mainly spleen are contracted driving its content of blood into the general circulation. ◊ Causes:it is due to: • ↑ed sympathetic activity. • ↑ed adrenalin secretion. Dr abdelaziz Hussein, Mansoura Faculty of Medicine

  16. Respiratory changes Dr abdelaziz Hussein, Mansoura Faculty of Medicine

  17. Respiratory changes a. Pulmonary VC: • It helps in reduction of the circulatory capacity and maintenance of blood volume. b. ↑ed Respiratory rate: helps; • More oxygenation of blood. • ↑ing the VR. ◊ Causes of ↑ed rate of respiration: • Local accumulation of metabolites in the central chemoreceptors and in the respiratory center neurons → due to ↓ of blood flow through them. Dr abdelaziz Hussein, Mansoura Faculty of Medicine

  18. Respiratory changes ◊ Causes of ↑ed rate of respiration: 2. ↓ed inhibitory impulses from the arterial baroreceptors due to ↓ ABP. 3. Cerebral ischemia ++ the VMC center that activates the resp. center. c. Depth of respiration; • It is variable; at first it becomes deep and later shallow. • Periodic respiration occurs before its failure. Dr abdelaziz Hussein, Mansoura Faculty of Medicine

  19. Blood Changes Dr abdelaziz Hussein, Mansoura Faculty of Medicine

  20. Blood changes • a. Coagulation of blood: • It is an important protective mechanism in stopping hemorrhage. • The thromboplastin released by the injured tissues start the clotting mechanism. • b. VC of the injured vesselsand the drop of blood pressure→ help the blood clot to seal the vessels. Dr abdelaziz Hussein, Mansoura Faculty of Medicine

  21. Blood changes • c. Formation of erythropoietin; • It stimulates the production of RBCs by the bone marrow. • d. Release of serotonin: • It is released from disintegrated platelets causing VC of the blood vessels. • e. Adrenaline release: • It helps formation of fibrinogen, prothrombin and factor V in the liver, for blood coagulation Dr abdelaziz Hussein, Mansoura Faculty of Medicine

  22. Kidney Changes Dr abdelaziz Hussein, Mansoura Faculty of Medicine

  23. Kidney changes • a) ↓ed Urine volume: • -It occurs 1st due to: • ↓ed ABP. • ↓ed blood volume and COP. • ↑ed ADH. • VC of the renal blood vessels. Dr abdelaziz Hussein, Mansoura Faculty of Medicine

  24. Kidney changes • b) Renal ischaemia: • It develops later on, it leads to: • i) Release of reninthat finally leads to production of angiotensin-II, which leads to; • Powerful VC. • Release of aldosterone→ causes retention of Na and H2O and excretion of excess K which is toxic. • ii)↓ed formation of urine, so reduces the amount of water loss. • iii) Release of erythropoietin→ stimulates the bone marrow to produce RBCs. Dr abdelaziz Hussein, Mansoura Faculty of Medicine

  25. Skin changes • ↑ed sympathetic discharge leads to: • VC of the capillaries → pale skin. • VC of the arterioles → cold skin. • Excessive sweating → cold sweat. Dr abdelaziz Hussein, Mansoura Faculty of Medicine

  26. Hormonal Changes Dr abdelaziz Hussein, Mansoura Faculty of Medicine

  27. Hormonal changes a- Catecholamines (adrenaline and noradrenaline) • Cause • VC of both arterioles and veins. • ↑ heart rate and stroke volume. • ++ of secretion of ACTH and glucocorticoids. • Help blood clotting by releasing fibrinogen and prothrombin from the liver and activating factor V. • Stimulate CNS, so patient becomes restlessness. • VR is ↑ed due to ↑ed ms pumps. • Contraction of the spleen Dr abdelaziz Hussein, Mansoura Faculty of Medicine

  28. Hormonal changes a- Catecholamines (adrenaline and noradrenaline): • Their secretion is ↑ed from adrenal medulla due to ↑ed sympathetic discharge. Dr abdelaziz Hussein, Mansoura Faculty of Medicine

  29. Hormonal changes b- Angiotensin II and Aldosterone Dr abdelaziz Hussein, Mansoura Faculty of Medicine

  30. Hormonal changes • c. ADH: • It is secreted from posterior pituitary gland by; • Hypothalamic impulses. • Reflexly from baroreceptors. • It causes VC and ↑es water reabsorption from the renal tubules, ABP is ↑ed to normal. • d- Erythropoietin: mentioned before Dr abdelaziz Hussein, Mansoura Faculty of Medicine

  31. Delayed Changes Dr abdelaziz Hussein, Mansoura Faculty of Medicine

  32. 1. Restoration of plasma volume • This is done by: • a. Withdrawal of fluid from interstitial and intracellular compartments into the blood. • b. ↑ed water reabsorption from the distal renal tubules by the aldosterone and ADH. • c. Intake of external fluid caused by thirst sensation as a result of tissue dehydration. Dr abdelaziz Hussein, Mansoura Faculty of Medicine

  33. 2. Replacement of plasma proteins • a. Rapid replacementfrom labile proteins in the liver and other tissues (completed within one hour). • b. Slow mechanismby new synthesis; • The normal concentration of plasma proteins is reached within one week. • A diet containing proteins of high biological value accelerates the synthesis. • Plasma proteins are important to maintain the effective osmotic pressure. Dr abdelaziz Hussein, Mansoura Faculty of Medicine

  34. 3. Restoration of RBCs volume a- Rapid restorationof RBCs by splenic contraction due to adrenaline release and sympathetic stimulation. b- Slow restorationof RBCs by the bone marrow. • This takes 3-5 weeks and is stimulated by: • Hypoxia. • Erythropoietin hormone • Growth hormone • Thyroxin hormone • Good nutrition with proteins, vitamins (B, C, B12, folic acid) and minerals (iron, cooper, cobalt). Dr abdelaziz Hussein, Mansoura Faculty of Medicine

  35. 4. Tissue Repair • To restore the integrity of the damaged tissues. 5. Recanalization of the closed blood vessels • By removal of the clots inside the vessels by plasminolysis. Dr abdelaziz Hussein, Mansoura Faculty of Medicine

  36. THANKS Dr abdelaziz Hussein, Mansoura Faculty of Medicine

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