Blood Therapy Flashcards
What is considered adequate urine output to assess intravascular fluid volume?
0.5-1ml/kg/hr.
List some clinical assessments for intraoperative blood loss?
Tachycardia. Hypotension. Oliguria. Decrease CVP. Decrease mixed venous oxygen. Large variation of systolic BP with RR
What is normal systolic BP variation with inspiration?
8-10mmHg
How much blood volume can a young healthy patient lose before demonstrating any clinical signs?
20%
What is a physiologic response to acute blood loss?
Vasoconstriction of splanchnic and venous capacitance vessels
What is the primary indication for blood transfusion?
To increase Oxygen carrying capacity
Transfusion is rarely justified with Hgb is greater than ___ and Hct is greater than ___?
Hgb>10g/dl
Hct>30%
Transfusion is almost always justified with Hgb is less than ___ and Hct is less than ___?
Hgb<6g/dl
Hct<18%
What is a rough estimate of Hct based on a Hgb value?
Hct is 3x Hgb
What blood product is preferred when blood loss leads to hypovolemic shock?
Whole Blood
How is crossmatching different than blood typing?
Typing checks for antibodies in the patient’s blood.
Crossing (crossmatching) tests the patients blood with the donor’s blood
What is crossmatching and how long does it take?
Three step process of testing patient blood with donor blood in an incubator. Takes approx 45mins
Which blood type is considered the universal donor?
O Negative
Which blood type is considered the universal recipient?
AB+
Which methods allows for a unit of blood to be available for more than one patient?
Type and Screen
What is a type and cross?
Specific unit(s) of blood are typed, tested, and set aside directly for a specific patient.
What is the chance of significant hemolytic reaction with typed and screened blood?
1:10,000
Which is ordered for a surgical procedure when the risk of transfusion is remote?
Risk of transfusion is very high/likely?
Remote risk= Type and Screen.
Likely risk= Type and Cross
How long can blood be stored?
21-35 days
What is the determining quality of why blood cannot be stored longer?
Must have at least 70% of the RBC be viable for more than 24 hours after transfusion
What is the average Hct of whole blood?
40%
What preservatives are used in donated blood?
Phosphate-acts as buffer.
Dextrose- provides energy to RBC.
Adenine-resynthesized ATP to fuel metabolic requirements
What is the volume and Hct of Packed Red Blood Cell (PRBC) unit?
300ml and 70% Hct
How much will one unit of PRBCs effect Hemoglobin concentration?
Increase by 1g/dl per unit
What would a hypotonic solution do to RBCs if it were to be mixed with blood product?
The cells would swell and and cell lysis would occur.
Which has a higher risk of citrate toxicity- whole blood or PRBC?
Whole blood
Which has high risk of allergic reaction-whole blood or PRBC?
Whole blood
What is the threshold for platelet replacement?
<50,000
How much will the platelet count go up per unit in 70kg patient?
Increase by 5,000-10,000 cells/mm3 per unit
What are some risks with platelet administration?
Transmission of viral diseases.
Bacterial infection 1 in 12,000.
Small risk of platelet related sepsis
What is a symptom of platelet sepsis after platelet administration?
Fever
FFP administration is specific indicated for what clinical factor?
Prothrombin time and/or Partial Thromboplastin time are greater than 1.5 times normal.
What are two other indications for FFP administration?
- Reversal of warfarin therapy.
2. Known factor deficiencies.
What is cryoprecipitate?
Basically concentrated FFP with high concentrations of Factor VIII, Factor XIII, Von Willebrand Factor, Fibrinogen, Fibronectin.
How is blood product administration determined based on coagulation studies? how many PRBCs:how many FFP: how many platelets, etc?
TEG
What are the 3 types of transfusion reactions?
- Febrile transfusion reaction.
- Allergic transfusion reaction.
- Hemolytic transfusion reaction.
What is the most frequently occurring transfusion reaction?
Febrile transfusion reaction.
How do you differentiate between hemolytic transfusion reaction, and the other two types?
Hemolytic transfusion reaction can be confirmed by patients serum and urine hemolysis. Free Hemoglobin in urine is a sign.
What are the three main signs of allergic transfusion reaction?
Urticaria.
Pruritus.
Occasional facial swelling
What causes an allergic transfusion reaction?
Due to presence of incompatible plasma proteins in the donor blood.
What is treatment for allergic transfusion reaction?
Stop infusion.
Benadryl.
What causes a hemolytic transfusion reaction?
Administration of erroneous unit of blood to a patient
How much blood can potentially cause a hemolytic transfusion reaction?
As little as 10ml of blood; however, severity of reaction is proportional to the volume of erroneous blood administered.
Ultimately, what two things can happen with hemolytic transfusion reaction?
Renal failure and DIC
Why does renal failure occur with hemolytic transfusion reactions?
Precipitates accumulate in the renal tubules.
What is preventative treatment for renal failure in the presence of hemolytic transfusion reaction?
Maintain 100ml/hr urine output with administration of LR and mannitol/furosemide
What are some metabolic complications of blood therapy?
Metabolic alkalosis.
Hypocalcemia.
Decreased 2,3 diphosphoglycerate levels.
Increased serum hydrogen and K+
Stored blood becomes more acidic or more alkaline as time goes on?
More acidic.
Does blood administration make the patient’s blood more acidic or more alkaline?
More alkaline.
Why does blood product make patient’s blood more alkaline even though the product itself is acidic?
Citrate being broken down into HCO3.
Left shift on hemoglobin/oxygenation curve causes what? Right shift?
Left shift=Greater O2 Affinity.
Right shift=Lesser O2 Affinity.
Is decreased concentration of 2,3 diphosphoglycerate associated with left or right shift?
Left shift=Increased Affinity of O2
What are complications of blood therapy related to transmission of viral disease?
HIV 1:1,000,000.
Hepatitis 1:60,000
Why is a filter used on blood products?
Mircoaggregates- mostly leukocytes and platelet clots can cause accumulation in lungs and contribute to ARDS
What is the standard filter for blood product and preferred filter?
Standard=170um diameter
Preferred=10-40 um diameter
What is DIC?
Patient’s coagulation and fibrinolytic systems become uncontrollably activated. Leads to platelet consumption and clotting factors.
What is treatment for DIC?
Treat underlying cause.
Administer platelet and FFP
What is TRALI?
Transfusion Related Acute Lung Injury
What is the only treatment for TRALI?
Supportive therapy
What are contraindications of intraoperative blood salvage?
Open bowel surgery, Septic/infected surgical site, malignancies, blood-borne pathogens.
What patient population is intraoperative salvage/autologous blood transfusion used in?
Jehovah’s Witnesses.
What is therapeutic hemodilution?
Removal or blood before induction and restored with crystalloid or colloid.
Then given back to the patient after blood loss has occurred. Form of autologous transfusion
Is patient consent required for hemodilution technique?
No
What is the threshold for FFP administration?
INR>2.0
PT/aPTT >1.5x normal
How is Allowable Blood Loss (ABL) calculated?
[EBV x (Hct-target Hct)] / Hct
What is average EBV for Male? Female? Obese?
Male=70-75ml/kg
Female=65-70ml/kg
Obese=55ml/kg
How to calculate fluid deficit?
4:2:1 method x # hours NPO
What is best way to replace fluid deficit via the traditional method?
Half of fluid deficit in first hour of surgery. Quarter in 2nd hour. Quarter in 3rd hour
