Fluids and Blood Flashcards
What two compartment make up the ECV?
ECV = 34% of TBW, 2-% body mass
- Plasma volume
- Interstitial volume
How do you estimate fluid deficit?
4-2-1 rule
1-10kg = 4ml/kg/hr
11-20 = 40 + 2ml/kg/hr
Each kg >20kg = 60 + 1ml/kg/hr
Fever - for each degree >37, add 2.5ml/kg for every 24 hours
List 4 signs of hypovolemia
- dry mucous membranes
- dec sensorium
- dec UOP
- dec or variable BP with position and PPV
What 3 things most commonly cause fluid loss during surgery?
- Evaporation
- Internal redistribution
- Blood loss
What is the ratio of blood loss to crystalloid replacement?
1L blood : 1.3-1.6L crystalloid
What are the contents in Normal Saline?
pH 5.0
Osmolality 308
Na 154
Cl 154
What are the contents in LR?
pH 6.5 Osmolality 275 Na 130 Cl 109 K 4 Ca 3 Lactate 28
What are the contents in Plasmalyte?
pH 7.4 Osmolality 294 Na 140 Cl 98 K 5 Mg 3
What are some side effects from using Hetastarch?
anticoagulant effects >20 mL/kg/day or 1L
decreased function of:
factor VIII
von Willebrand factor
fibrinogen
PRURITIS
Increased M&M in critically ill patients
What evidence is there about relative benefits and risks of crystalloid vs. colloid resuscitation?
SAFE study
No significant differences were found with respect to mortality
Albumin & hetastarch were found to be associated with higher mortality in patients with traumatic brain injury
What are some side effects from using Dextran?
decreasing platelet aggregation
prolonged bleed time
allergic reactions
Crystalloid solution associated with hyperchloremic metabolic acidosis in volumes >3L
NS
How much should transfusion of one unit of PRBCs increase [Hbg], in the absence of continued bleeding?
1g/dL
Describe the components of a unit of PRBCs
180 ml of RBCs
30 ml of citrate-phosphate-dextrose (CPD) anticoagulant preservative.
30 ml of plasma
Describe the symptoms of acute hemolytic reaction
awake patient - pain at the infusion site, dyspnea, chest pain, flank pain and rigors
anesthetized patient - red urine, hypotension, fever, and coagulopathy
- STOP transfusion
What is the starting dose for transfusion of FFP? What is the goal of FFP transfusion?
10-15 mL/kg, with the goal of achieving 30% of clotting factor concentration
What are the components of FFP?
250ml of volume
ALL plasma proteins and clotting factors
= not a concentrate of any of the clotting factors = should NOT be used to treat specific deficiencies (hemophilia) unless factor concentrates are not available
How is FFP stored and how long is its shelf life?
FFP is frozen at -18 to -30°C within 8 hours of collection
Gently thawed in water bath –> used within 6 hours
Used up to 1 year after collection
What are some indications for use of FFP?
- Rapid and emergent reversal of warfarin (one could also use Factor VIIa or various available concentrates of Factors II, VII, IX, and X).
- Correction of factor deficiencies in the absence of available factor concentrates.
- Correction of AT-III deficiency for patients receiving heparin (often in the setting of cardiac or vascular surgery, but a specific concentrate is also available).
- Correction of non-surgical (microvascular) bleeding in patients who have been transfused more than one blood volume.
- Correction of microvascular bleeding in patients with abnormal coagulation parameters. This applies to a PT more than 1.5 times normal, an aPTT more than 2 times normal, and an INR more than 2.0.
What are the implications of platelet storage temperature?
must be stored at room temperature = higher risk of transmitting infection and a shorter shelf life
What is the most common reason anesthesiologists transfuse cryoprecipitate?
microvascular bleeding + fibrinogen level
What is currently the best reason to administer dextrans?
plastic or vascular surgery to improve perfusion and decrease the risk of thrombosis
Where does cryoprecipitate come from and what are its contents?
FFP is thawed at 4°C, a precipitate remains, which can be separated by centrifugation = cryoprecipitate
Factor VIII Factor XIII von Willebrand factor Fibrinogen Fibronectin
Is ABO compatibility necessary for:
- Platelets?
- FFP?
- No - but incompatible –> shorter half-life
2. Yes
What changes occur during PRBC storage?
pH drops potassium increases calcium and magnesium decrease (citrate binds them) factors V and VIII degrade PRBCs lyse
Why is clinically significant hyperkalemia after massive transfusion unlikely in patients with normal renal function?
K = 19-30 mEq/L after 21 days of storage due to leakage from PRBCs as well as PRBC lysis –> hyperkalemia during massive transfusion at rates of >120 ml/min
What is the preferred test to follow calcium levels during and after massive transfusion?
Ionized Ca
Total serum calcium will measure citrate-bound calcium + free calcium in the ionized form and may not accurately reflect free serum calcium
Why is metabolic alkalosis more commonly induced by massive transfusion rather than metabolic acidosis?
citrate in stored blood is metabolized to bicarbonate by the liver via the Krebs cycle
low pH of citrate-containing storage solutions + erythrocyte metabolism forming lactic acid and pyretic acid –> pH 6.5 after 35 days of storage
storage containers impermeable to CO2 –> to pCO2 levels of 150-200 mmHg.
Acidosis in the setting of hemorrhage is more likely due to hypo perfusion –> anaerobic metabolism in peripheral tissues and consequent accumulation of lactic acid
What are the manifestations of citrate toxicity?
signs and symptoms of HYPOCALCEMIA: *hypotension* narrow pulse pressure increased intraventricular end-diastolic pressure prolonged QT interval
What factors can lead to accumulation of citrate?
Poor liver function –> slow metabolism by liver
Hypothermia –> dec metabolism
Name 5 factors that contribute to coagulopathy during massive transfusion.
hypothermia tissue injury acidosis duration of shock DIC
What is the generally accepted platelet level below which clinically significant surgical bleeding is more likely?
50,000
How does massive transfusion inhibit proper function of clotting factors?
deficiency of most clotting factors, especially factors V and VIII and fibrinogen
probably occurs as a result of dilution
Describe how hypothermia contributes to bleeding in the setting of massive transfusion.
non-functional enzyme clotting factors
Lethal Triad
- hypothermia
- coagulopathy
- acidosis
What is the shelf life of appropriately harvested and preserved red blood cells?
Whole blood and RBC components in storage solutions such as CPDA-1 (citrate, phosphate, dextrose, adenine) = 35-42 days at 2-6 degrees C
Rare RBC blood types may be frozen in glycerol and stored for up to ten years
What length of time may transpire between thawing and using fresh frozen plasma?
6 hours
If the FFP unit is not transfused within the pre-specified 6 hours, it can be refrigerated and returned to blood bank, where it may be re-released for clinical use within 24 hrs
FFP can be stored for up to seven years at -65 degrees C
Name the three major components of cryoprecipitate.
Factor VIII
von Willebrand Factor
fibrinogen
What is the typical unit dose of cryoprecipitate?
1 unit per 10 kg of body weight (using lean body weight approximations)
This dose increases plasma fibrinogen concentration by 50-75 mg/dL
What is the shelf life of platelet concentrates?
3-5 days
Why must platelet concentrates not be stored in the cold?
20-24 deg C (room temperature) with continuous agitation, as cold-exposed platelets lose viability and are rapidly cleared by the reticuloendothelial system
Summarize the “thirty-minute rule”.
no blood component should be outside the target temperature range for transport or storage for more than thirty minutes.
List four deleterious effects of red blood cell metabolic activity on the quality of stored blood.
loss of ATP
loss of 2,3-DPG (resulting in increased affinity of hemoglobin for oxygen, shifting the curve LEFT)
increased cellular rigidity
accumulation of supernatant K+
What is the purpose of a leukoreduction filter?
reducing white blood cell-mediated transfusion reactions such as: non-febrile hemolytic reactions alloimmunization graft-versus-host disease cytomegalovirus transmission transfusion-related acute lung injury
4mm
When are microaggregate filtration systems used?
Cardiopulmonary bypass
20-40mm
cell-saver equipment to filter out microaggregates composed of fibrin, platelets and leukocytes - impact debatable
Cryoprecipitate storage
Frozen at temps less then -20 deg C –> prevent degradation of clotting factors
Transfused w/in 4 hours of release
Transfused at room temperature
What causes febrile non-hemolytic transfusion reactions?
recipient antibodies reacting to donor HLA or other antigens and also from the release of cytokines and intracellular contents by donor leukocytes
diagnosis of exclusion when the temperature increases by greater than 1°C during or within hours of transfusion
Urticarial transfusion reactions are caused by what mechanism?
Anaphylactoid reaction - reaction to donor plasma proteins
Give anti-histamines
What is the mechanism of an anaphylactic response to transfusion?
interaction of recipient antibodies with donor plasma IgA and occur in IgA-deficient patients with anti-IgA antibodies
Washed RBCs with all donor IgA removed or blood products lacking IgA protein can be given to these patients.
What are the most serious consequences of a hemolytic transfusion reaction and how do you treat them?
ABO incompatibility
recipient Ab directly attacking transfused donor cells, causing intravascular hemolysis and complement activation
Tx - stopping the transfusion and supportive care, focusing on renal failure prevention (particularly maintaining adequate urine output, and alkalization of urine)
Which patients are likely to have a delayed hemolytic transfusion reaction and what would their symptoms be?
developed an Ab, usually to an antigen like Rh or Kidd, during prior transfusions or pregnancy and do not have a sufficient titer to result in positive agglutination or to cause immediate hemolysis
What are the signs and symptoms of a hemolytic transfusion reaction?
awake patients - N, chest, flank pain. anxiety, SOB anesthetized patients - 1st = hemoglobinuria –> hypotension and a bleeding diathesis
What is the mechanism of transfusion associated GVHD?
donor leukocytes engraft and initiate a reaction to recipient tissues
risk can be minimized by irradiating blood products
Signs and symptoms - fever, anorexia, rash, abdominal pain, vomiting, diarrhea, cough, and pancytopenia. GVHD is almost always fatal
Define transfusion related acute lung injury (TRALI).
non-cardiogenic pulmonary edema, frothy sputum from ETT, hypoxemia, respiratory distress, hypotension, fever, and cyanosis
Define transfusion associated cardiac overload (TACO).
pulmonary edema resulting from transfusion in individuals with limited cardiac reserve
LV dysfxn + FFP to reverse anti-coagulation
Describe the immune mechanism of TRALI.
anti-leukocyte antibodies from donor plasma
Trapped hyper-reactive neutrophils release enzymes and reactive oxygen species –> injure pulmonary endothelium –> increased leakage of protein rich fluid and neutrophil emigration –> pulmonary edema
Describe the non-immune mechanism of TRALI.
biologically active lipids that accumulate during the storage of the blood products –> alveolar damage –> increases permeability of pulmonary circulation and results in pulmonary edema.
What is the treatment of TRALI?
Modest resp distress, hypotension = O2
More severe = mechanical ventilation, pressors
Describe the pathophysiology of TACO.
Excess transfusion volume overwhelms patient’s cardiovascular system - unable to compensate
increase in systemic and pulmonary blood volumes –> increased hydrostatic pressures within the pulmonary vasculature, leading to pulmonary edema.
List the risk factors for developing TACO
extremes of age congestive heart failure renal impairment hypoalbuminemia fluid overload (i.e., a positive fluid balance) in the 24 hours prior to transfusion.
List risk factors for developing TRALI.
Risk factors include sepsis, liver disease, alcohol abuse, and mechanical ventilation
plasma-containing product from multiparous female donor
List some preventative measure for reducing TACO
slower rate of transfusion
preemptive diuretics
What is the treatment for TACO?
stop the transfusion
place the patient in an upright position
provide supplemental oxygen
If symptoms persist –> diuretics can be used to reduce plasma volume.
Patients with severe symptoms may require intubation and positive pressure ventilation.
Describe the bronchial fluid c/w TRALI.
high protein content with cell debris present
high specific gravity (>1.020)
pleural fluid protein/serum protein >0.5
pleural fluid LDH/serum LDH >0.6
Which viral infection has the greatest risk of transmission via blood transfusions?
Hepatitis B: 1 out of 205,000
What are the most common signs and symptoms of a Hepatitis C infection?
1 in 1,935,000
Fatigue and hepatomegaly
What is the risk of getting an HIV infection after a blood transfusion?
1 out of 2,135,000
Which patients should be given CMV seronegative blood products?
Preterm neonates
newborns
pregnant women receive CMV seronegative blood to prevent CMV infections in the infants
Human T-cell lymphotropic virus type 1 (HTLV-1) has been causally associated with what condition?
adult T-cell leukemia/lymphoma
tropical spastic paraparesis
Bacterial infections of gram-negative bacteria are most likely to occur in which blood product?
PRBCs
Bacterial infections of gram-positive bacteria are most likely to occur in which blood product?
Products stored at RT = platelets
What is the definition of massive transfusion?
greater than 10 units of packed red blood cells (PRBCs) over a 24-hour period
Replacement of 1/2 a patient’s blood volume within 3-4 hours or greater than 4 units of PRBCs in 1 hour with a foreseeable ongoing need
What are the three components of the Lethal Triad?
hypothermia
acidosis
coagulopathy
How does a 1°C drop in temperature affect coagulation and at what temperature does severe hypothermia simulate factor deficiency states?
10% reduction in coagulation factor activity.
Below 33°C - coagulopathy –> is similar to factor deficiency states. There is also a decreased ability to form stable clots.
What are the three types of coagulopathy?
dilutional
consumptive
thrombocytopenic
How does a lactate level relate to acidosis?
increase in lactate due to inadequate clearance
What is the risk of transfusing old blood quickly and what rates are known to cause problems?
Higher K levels >77mEq/L
Irradiation inc K+
Rates >100-150 ml/min can be associated with hyperK cardiac arrest.
How should the anesthesiologist monitor calcium levels during rapid transfusion?
Stored blood is anticoagulated with citrate, which chelates calcium (Ca2+)
monitor serum ionized/free calcium levels
What is the mechanism of citrate toxicity and what are the manifestations?
Citrate is metabolized to bicarbonate, which can cause a metabolic alkalosis and can lower serum K+.
prolonged QT interval decreased myocardial contractility hypotension from decreased peripheral vascular resistance narrow pulse pressure elevated CVP pulseless electrical activity ventricular fibrillation
What factor limits the amount of autologous blood a patient can pre-donate?
higher K+
lower levels of coagulation factors
= allogeneic blood transfusion avoided if the anticipated volume needed >4-6Units = oldest blood will be 28 days old or greater (donating 1 unit weekly)
Name three organs that may be damaged by transfusion of hemoglobin-based oxygen carriers
myocardium, liver, and kidneys
What is the biological origin of the erythropoietin currently used in humans?
genetically engineered bacteria
Humans - glycoprotein hormone produced by the peritubular cells of the kidney
a cytokine for RBC production in the bone marrow by promoting blast cell maturation
OK for Jehovah’s witnesses
OK for elective, non-cardiac surgery
What are the three categories of rejection based on timing?
Hyperacute rejection - first 24 hours
acute rejection - weeks
chronic rejection - months to years
What aspects of T cell activation are targeted by immunosuppressive drugs?
Prednisone, muromonab-CD3 (Orthoclone OKT3) and 15-deoxyspergualin (Gusperimus) = Inhibit T cell interaction
Rabbit/horse antithymocyte globulin and antilymphocyte globulin = Inhibit adhesion molecules
Cyclosporine, tacrolimus and sirolimus = Inhibit cytokine synthesis
Azathioprine and mycophenolate mofetil = Inhibit DNA synthesis
What immunosuppressive drugs are associated with fevers and anaphylaxis?
the globulins
What immunosuppressive drugs require monitoring of drug levels?
Cyclosporine, tacrolimus and sirolimus
How does cyclosporine interact with common anesthetic drugs?
cyclosporine
- may alter barbiturate, fentanyl and isoflurane requirements
- may enhance neuromuscular blockade
- may cause moderate increases in benzodiazapine concentrations
What drugs increase and deacrease tacrolimus levels?
Increase = amiodarone, levofloxacin
decrease = phenytoin, carbamazepine, rifampin
What anti-infective agents interact with tacrolimus?
Gentamicin and amphotericin B inc risk of nephrotoxicity
