body fluids

Question 1

explain hypotension with tachycardia resulting from blood loss

Answer 1

loss of blood volume, therefore, cardiac filling decreases and therefore CO – decreased P

Must be hemorrhagic shock >10% loss of BV, firing of baroreceptor and cardiac receptors is reduced

neuro-humoral response by increasing sympathetic drive and decreasing parasympathetic

Question 2

describe anaemia due to blood loss

Answer 2

low mean pressure which decreases in pre-capillary system causing low mean capillary hydrostatic pressure. This favours the absorption of fluid and reduces haematocrit

Question 3

why does a patient with blood loss have high creatinine

Answer 3

serum creatinine is a reflection of GFR

low BP, therefore, reduced perfusion to renal and lack of clearance of creatinine in the kidneys

Question 4

hyperkalamia in acidosis

Answer 4

protons (H+) move into cell to buffer acid causing K+ ions to leave cell to maintain electroneutrality

acidosis can cause kidney impairment and therefore lack of K+ excretion from kidneys

Question 5

why does an acidotic patient become more thirsty

Answer 5

• disrupted plasma osmolality (sensed by osmoreceptors)

- increased angiotensin 2

Question 6

what causes natriuresis and diuresis

Answer 6

increased levels of ANP from increased BP

and low levels of RAAS and ADH

Question 7

why do patients go cold and pale when large volumes of blood are lost

Answer 7

less peripheral circulation by sympathetic stimulation and loss of perfusion

Question 8

why do patients go sweaty during blood loss

Answer 8

high levels of circulating catecholamines, giving activation of sweat glands

Question 9

what does it mean if a patient has normal Hb during blood volume loss

Answer 9

suggests the blood loss is acute, theres no dilution of Hb due to the transfer of tissue fluid into the vascular space

Question 10

why might a patient with blood loss have elevated cortisol

Answer 10

due to stress

Question 11

explain abdominal bruit

Answer 11

stenosis causes increased velocity of flow, giving turbulent flow downstream, vibrations of this heard as bruit on auscultation

Question 12

what does a low urinary Na excretion and low serum K show

Answer 12

that theres an over activated RAAS system giving high aldosterone

• more Na+ reabsorption so less excreted in urine
• excretion of K, giving low levels in the serum