ﺑﺴﻢ ﺍﻟﻠﻪ ﺍﻟﺮﺣﻤﻦ ﺍﻟﺮﺣﻴﻢ ﻭ ﻣﺎ ﺃﻮﺗﻴﺘﻢ

ﺑﺴﻢ ﺍﻟﻠﻪ ﺍﻟﺮﺣﻤﻦ ﺍﻟﺮﺣﻴﻢ ﴿ﻭ ﻣﺎ ﺃﻮﺗﻴﺘﻢ ﻣﻦ ﺍﻟﻌﻠﻢ ﺇﻻ ﻗﻠﻴﻼ﴾ ﺻﺪﻕ ﺍﻟﻠﻪ ﺍﻟﻌﻈﻴﻢ ﺍﻻﺳﺮﺍﺀ ﺍﻳﺔ 85 Dr abdelaziz Hussein, Mansoura Faculty of Medicine

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

Haemorrhage Dr abdelaziz Hussein, Mansoura Faculty of Medicine

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

◊ Types: Haemorrhage 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 Dr abdelaziz Hussein, Mansoura Faculty of dangerous than chronic bleeding. Medicine

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

Haemorrhage ◊ Manifestations of haemorrhage: 1. ↓ed ABP. 2. The pulse is rapid, weak and feeble 3. Respiration is rapid, but the depth of respiration is at first deep then shallow. 4. The cutaneous veins are collapsed and fill slowly when compressed centrally. 5. The skin is pale, cold, moist, and slightly cyanotic. 6. Oliguria. 7. Fainting may occur. Dr abdelaziz Hussein, Mansoura Faculty of Medicine

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

Haemorrhage • Haemorrhage has 2 effects; Immediate Delayed CVS system Plasma volume Respiratory Plasma proteins Kidney RBCs Endocrine Tissue repair Skin Blood Dr abdelaziz Hussein, Mansoura Faculty of Medicine Recanalization of blood vessel

Immediate Compensatory Changes Dr abdelaziz Hussein, Mansoura Faculty of Medicine

CVS changes 1. Cardiac acceleration or ↑Heart Rate 2. ↑ed vasoconstri ctor discharge Vasoconstri ction Dr abdelaziz Hussein, Mansoura Faculty of Medicine 3. Contraction of blood reservoir

CVS changes a. Cardiac acceleration: ◊ Causes: ↑ed heart rate may be due to; 1. ↓ed ABP, ↑es heart rate by Mary's law. 2. ↑ed adrenaline secretion stimulates SAN directly. 3. 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 Dr abdelaziz Hussein, Mansoura Faculty of Medicine coronary blood vessels.

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

CVS changes • b. ↑ed vasoconstrictor discharges: ◊ Causes of VC: 1. ↑ed secretion of epinephrine and norepinephrine. 2. ↓ed depressor impulses from the arterial baroreceptors. 3. ↓ed VR leads to reflex VC of the arterioles and venules (Mc Dowa s reflex). 4. ↑ed secretion of vasopressin. 5. Release of serotonin from platelets. 6. Renal ischemia leads finally. Mansoura Faculty of angiotensin II. to VC by Dr abdelaziz Hussein, Medicine

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: 1. ↑ed sympathetic activity. 2. ↑ed adrenalin secretion. Hussein, Mansoura Faculty of Dr abdelaziz Medicine

Respiratory changes 1. Pulmonary V. C. 2. ↑ed Rate of Respiration Dr abdelaziz Hussein, Mansoura Faculty of Medicine 3. Depth of Respiration

Respiratory changes a. Pulmonary VC: • It helps in reduction of the circulatory capacity and maintenance of blood volume. b. ↑ed Respiratory rate: helps; 1. More oxygenation of blood. 2. ↑ing the VR. ◊ Causes of ↑ed rate of respiration: 1. 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

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

Blood Changes 1. Coagulation of blood 2. VC of the injured vessels Dr abdelaziz Hussein, Mansoura Faculty of Medicine 3. Formation of erythropoie tin, Adrenaline, and serotonin

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 vessels and the drop of blood pressure→ help the blood clot to seal the vessels. Dr abdelaziz Hussein, Mansoura Faculty of Medicine

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 Dr abdelaziz Hussein, Mansoura Faculty of Medicine

Kidney Changes 1. ↓ed Urine volume 2. Renal Ischemia Dr abdelaziz Hussein, Mansoura Faculty of Medicine

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

Kidney changes • b) Renal ischaemia: • It develops later on, it leads to: • i) Release of renin that finally leads to production of angiotensin. II, which leads to; • Powerful VC. • Release of aldosterone→ causes retention of Na and H 2 O 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

Skin changes • ↑ed sympathetic discharge leads to: 1. VC of the capillaries → pale skin. 2. VC of the arterioles → cold skin. 3. Excessive sweating → cold sweat. Dr abdelaziz Hussein, Mansoura Faculty of Medicine

Hormonal Changes 1. Catecholami nes 2. Angiotensin II and Aldosterone 3. ACTH and Glucocorticoi ds 4. Erythropoieti n Dr abdelaziz Hussein, Mansoura Faculty of Medicine 5. ADH

Hormonal changes a- Catecholamines (adrenaline and noradrenalin • Cause 1. VC of both arterioles and veins. 2. ↑ heart rate and stroke volume. 3. ++ of secretion of ACTH and glucocorticoids. 4. Help blood clotting by releasing fibrinogen and prothrombin from liver and activating factor V. 5. Stimulate CNS, so patient becomes restlessness. 6. VR is ↑ed due to ↑ed ms pumps. Dr abdelaziz Hussein, Mansoura Faculty of Medicine 7. Contraction of the spleen

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

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

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

Delayed Changes Dr abdelaziz Hussein, Mansoura Faculty of Medicine

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

2. Replacement of plasma proteins • a. Rapid replacement from labile proteins in the liver and other tissues (completed within one hour). • b. Slow mechanism by 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

3. Restoration of RBCs volume a- Rapid restoration of RBCs by splenic contraction due to adrenaline release and sympathetic stimulation. b- Slow restoration of RBCs by the bone marrow. • This takes 3 -5 weeks and is stimulated by: 1. Hypoxia. 2. Erythropoietin hormone 3. Growth hormone 4. Thyroxin hormone 5. Good nutrition with proteins, vitamins (B, C, B 12, folic acid) and minerals (iron, cooper, cobalt). Dr abdelaziz Hussein, Mansoura Faculty of Medicine

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

THANKS Dr abdelaziz Hussein, Mansoura Faculty of Medicine