Fluids And Blood Flashcards
What is the blood volume of an adult?
70 ml per kg men lean body mass
65 women and elderly men
What is the blood volume of a neonate?
90 ml / kg lean body mass
Formula for volume of packed red cell needed?
PRBC = IBV x change in Hct/70 ml
1,5x weight x (hct2-hct1)
maintenance fluid dose for adults?
1-2 ml/kg/h
What is maintenance fluid?
Compensate for normal fluid losses eg respiration, skin, urine, bowel losses
Which fluid should be used for replacement upper git losses?
Losses rich in chloride, hydrogen and potassium so give normal saline with potassium
Which fluid should be used for replacement lower git losses?
Losses rich in bicarbonate so replace with normal saline with potassium and bicarb
Replacement fluid dose for burns patients?
Parkland formula Ringers
4 ml /% burns/kg/h
Half replacement in 8 hours, other half in 16 hours.
If NPO, maintenance x hours NPO and give 50% during first hour.
When should blood transfusion be done?
If > 20% blood loss
Oxygen flush formula?
Do2= co x caCo2
= co x (hb x 1,34 x Sao2 + 0,031 x pa02)
Formula for ASI and interpretation?
Awake shock index = pulse ÷ SBP
Normal = 0,4-0,7,
If 1 or more, will need blood transfusion due to severe shock
0,8-1= 10-20 % blood loss
1-1,5= 20-33%
1,5-2 = 33 -50%
> 2=50%.
Name the 7 end points of resuscitation
• Map >65 mm hg
• urine output > 0,5 ml/kg / h
• SVO2 > 70% (central venous oxygen saturation)
• CVP 8-12 cm H2O
• transfuse up to haematocrit of 30
• look at improvement ph, lactate
Blood volume of premature baby (<37 weeks birth)
95 ml/kg
Blood volume of infant ( 6 weeks - 12 months)?
80 ml / kg
Blood volume of child ( 1 to 12 years)?
70 ml / kg
Name the 2 groups of fluids with examples
Crystalloid’s
• isotonic: ringer’s lactate, normal saline
• hypertonic: dextrose solutions eg dextrose 5%
Colloids (starling equation)
• natural: albumin 5% and 25%, FFP
• synthetic: dextrans, gelatins (gelofusin), hydroxy-ethylstarches (voluven)
Compositions of normal saline? (11) NB
• Sodium 154 ( more than plasma)
• No potassium
• No magnesium
• No calcium
• chloride 154 ( more than plasma)
• no phosphorous
• no lactate
• no bicarb
• No glucose
• ph 5,5 (acidic, more so than Ringer’s)
• osmolarity 308 ( isotonic )
Composition of ringer’s lactate? (11) NB
• Sodium 131 ( less than plasma)
•potassium 5 (same as plasma)
• No magnesium
•calcium 1,8 ( less than plasma)
• chloride 112 ( more than plasma)
• no phosphorous
•lactate 29
• no bicarb
• No glucose
• ph 6,5 (acidic)
• osmolarity 279 ( isotonic )
Composition of plasmalyte B? (11) not nb
• Sodium 131 ( less than plasma)
•potassium 5 (same as plasma)
•magnesium 3 ( double plasma)
•No calcium
• chloride 112 ( more than plasma)
• no phosphorous
•no lactate
•bicarb 28 (same as plasma)
• No glucose
• ph 7,4 (normal)
• osmolarity 273 ( isotonic )
Name 3 advantages of using crystalloids as resuscitation fluids
• Easily obtainable and cheap
• just as efficient as volume expander as colloid if given in sufficient amounts
• patients may be dehydrated intracellularly so benefit from fluids that move intracellularly
Name 3 disadvantages of using crystalloids as resuscitation fluids
• Short intravascular half life: within 2 hours of admin < 20% remains intravascular
• increased risk diffuse interstitial oedema
• may cause hypercoagulable
(Last 2 due to damage by crystalloids to glycoprotein lining of Endothelium, the glycocalyx, which maintains endothelial homeostasis. )
Which 2 resuscitation crystalloid contain magnesium?
Plasmalyte B and balsol
Which crystalloids contain calcium? (2)
Ringer lactate and neonatalyte
Which crystalloids contain bicarb? (3)
Plasmalyte B (28), balsol (28), naHco3 8.4% (1000)
Which crystalloids have lowest ph?
Maintelyte in glucose (4)
Which crystalloids have lowest osmolarity?
Plasmalyte B and balsol (273) - closest to blood
Name 7 disadvantages and side effects of colloids
• Expensive
• anaphylaxis (especially gelatins)
• dilute red blood cells, platelets, clotting factors. Large volumes cause hypocoagulability by dilution thrombocytopenia (especially dextrans)
• fluid overload
• prolonged in renal failure
• pruritis
• increase incidence renal failure in septic patients
Name advantages colloids (2)
• Replace blood loss 1:1
• intravascular half life longer at 3-6 hours
Which fluid type is preferred for administration?
Start off with crystalloid
After 2 L , give colloid
Define massive transfusion (4)
•>10 units blood in first 24h
• entire blood volume in 24h
• > 50% blood volume in 3 hours
• 3 units in 1 hour (about 10 units in body)
What should Hb goal be in blood transfusion ?
6 g / dl in healthy patient
7 in associated disease
8 in acute coronary syndrome
Dose tranexamic acid in patient that has lost > 20% blood volume?
1g stat
What blood ratio should be given in blood transfusion?
1 blood: 1 plasma: 1 platelets
Name 4 mechanisms blood conservation
• Cell saver
• autologous blood transfusion
• haemodilution
• antifibrinolytics
When should platelets be prescribed?
Loss 1 blood volume
Name 6 transfusion reactions
• Acute haemolytic reactions: Abo incompatibility
• delayed haemolytic reactions: Rh
• allergic reactions: incompatible proteins
• graft vs host reaction
. Febrile non-haemolytic reactions
. Post transfusion purpura
Name 7 metabolic deviations and complications resulting from blood transfusion
• hyper k, hyper mg, hypo Ca (citrate in blood bind Ca)
• decreased ph
• decrease 2,3 dpg ( L shift oxy-Hb curve )
• ATP depletion
• release pro-inflammatory substances
• decrease platelets and clotting factor 5 and 8
• post-op infection if blood is old
What is TRALI and pathophysiology? (4)
• Transfusion related acute lung injury.
• 1-6 h after transfusion
• Patient hypoxic, no signs pulmonary oedema, white lungs
. Caused by FFP
Name 6 diverse reactions to blood transfusions
• Hypothermia
• citrate toxicity with decreased calcium
• fluid overload
• air embolism
• bacterial contamination
• bleeding tendency: dilution thrombocytopenia
How does hyponatraemia present and what are some causes and treatment in hypo, Normo and hyper volaemia? Surgical implication?
• <135 mmol/l
• acute picture: lethargy, confusion, seizures, coma
• hypovolaemia: electrolyte rich fluid loss, nv, diarrhoea, fistulae, diuretics, cerebral salt wasting syndrome. Treat with normal saline
• normovolaMia: siadh, hypothyroid, Addison’s. Treat with HRT and fluid restriction
• hyper volaemia: TURP syndrome, cardiac failure (secondary hyperaldosteronism), renal failure, cirrhosis. Treat with fluid restriction and diuretics
pseudohyponatraemia
• if <130, postpone sx: increase risk cerebral oedema, delayed awakening
• <120 high mortality! Treat slowly to prevent pontine demyelination
Fluid Resuscitation formula for bleeding adults?
Crystalloid: 3ml for every 1ml blood loss
Colloid:1ml for every 1ml blood loss
Composition of maintelyte? (Na, K, Mg, Ca, Cl, P, lactate, bicarbonate, glucose, PH, osmolality) NB
Na: 35 (much less than plasma)
K: 25 (much more than plasma)
Mg: 2,5 (same as plasma)
Ca: none
Cl: 65 (much less than plasma)
P: none
Lactate: none
Bicarb: none
Glucose: 100 (10%) or 50 (5%)
PH: 4 (most acidic)
Osmolality: 10% 683; 5% 405 (hypertonic)
Max dose of voluven per day?
45 ml/kg/day
Where in the body is most of the water content found?
Intracellular fluid compartment
What is the main electrolyte composition of extracellular fluid?
Sodium, chloride, bicarbonate
What is the main electrolyte composition of intracellular fluid?
Potassium, magnesium, phosphate
Name 2 indications voluven
• Good to replace acute and intra-op blood loss at ratio 1:1
• spinal to coload patient and expand intravascular volume- help with hypotension
Lowest risk anaphylaxis of all the colloids
Name 3 indications colloids
• Fluid resus in patients with severe intravascular deficits prior to initiating blood products
• fluid resus in presence severe hypoalbuminaemia or large protein losses eg burns
• when crystalloid replacement exceeds 3-4 L
Name 4 electrolytes found in volulyte
Sodium, potassium, chloride, magnesium, acetate
Name 2 adverse effects voluven
• Excreted by kidneys: renal disfunction
. Coagulopathy in elderly
Generic name voluven/volulyte/ venofundin?
Tetrastarch
When would saline be chosen over ringers for maintenance?
• low sodium that needs replacement
• high potassium
How decide when to transfuse
Look at hb (<10) and hct <30 but also clinical picture! And oxygen flush formula
= transfusion triggers
Formula for ml of red cell concentrate to transfuse?
VTT= ebv x (initial hct- current hct )÷ 70 ml
How are red cells concentrate stored?
Fridge at 4°c
How are fresh frozen plasma stored?
Freezer at -30°c
How are platelets stored?
At room temperature, kept agitated
How are cryoprecipitate stored?
Freezer at -30°c
NB name 7 transfusion triggers for platelets
• Massive blood loss with oozing in the surgical field
• massive transfusion
• trauma resuscitation with 1:1:1 ratio
• all surgical patients with absolute count <50
• neuro ophthalmic and hepatic surgery <100
• all other patients <10
Dose 10 ml/kg infants, 1 mega unit or 5ml/kg adults
How do hct and hb relate?
Hct = hb x 3
Name 5 types of blood products
• Whole blood
• red cell concentrate
• fresh frozen plasma (use for low clotting factors - all)
• platelets
• cryoprecipitate (clotting factors - only VIII, XIII, vWF)
Name 6 changes in stored blood (NB)
• Decreased ph secondary to continued metabolism
• increased PCO2 and lactate
• increased potassium
• decreased 2,3 DPG - left shift oxy-hb dissociation curve
• platelets only viable 1 day
• decreased clotting factors. V and vIll
Name 8 transfusion triggers for red cells
• All patients with hb ≤ 60 g / l (6g/dL)
•>80 years with hb ≤ 70
• CVD with hb ≤ 80
• increased vo2 (oxygen consumption: high temperature, high metabolism) with Hb ≤80
• infants with hb <90
• haemodynamic: relative tachycardia (>110-130 bpm from baseline) or relative hypotension (<55 from baseline in healthy, <70-80 in CVD and HT, higher severely HT)
• myocardial ischaemia: new ST segment depression > 0,1mv or elevation > 0,2mV; or Clinical signs confirmed with ECG and or troponin
• central venous oximetry 1 or more: pv02 <32 mmHg , scvp02 <50% , o2er > 50%, decrease vo2 > 10%
