Intra-op Fluid Management Flashcards
How do you replace fluid according to the historical school of thought?
- insensible fluid loss—> from urine, feces, sweat, resp.
- replace with 2mL/Kg/Hr
- 3rd spacing: depends of size of fluid shift
- minimal trauma: 3-4 ml/kg
- moderate trauma: 5-6mL/kg
- severe trauma 7-8mL/Kg
(Huge incision)
How is fluid loss replaced according to new thought/ periop goal directed fluid therapy (PGDT)?
- use hemodynamic monitoring to guide fluid replacement
- dilution: CO with PAC
- pulse contour: vigileo/flow track
- echo/es. Doppler
- give 250mL bolus and monitor cardiac response to determine if pt needs fluids or meds (frank-starling curve)
- ERAS—> build them up bore, then when we knock them down they don’t have as far to climb
- minimizes fluids
What is true regarding crystalloids?
- cross plasma membrane- may dilute plasma proteins
—> increased risk of pulmonary edema in large volumes - when replacing blood loss: crystalloid is 3 xs blood loss amount, in order to account for volume loss and 3rd spacing (historic)
** no glucose containing solutions—> BAD.
Usually just use isotonic
What is true regarding colloids?
- use 1:1 to replace blood loss
- colloids stay in plasma
- hetastarch- not used much d/t coagulopathies (decreases factor VIII)
- dextran- decreases platelet adhesiveness, potential for anaphylaxis, interferes with blood crossmatch—>not used much
- 5% Albumin: used for rapid expansion of intravascular volume
(25% causes higher pull, mostly used in ICU)
What are s/s blood loss?
- tachycardia, hypotension, decreased CVP, decreased mixed venous O2
- give pain meds, if no ∆, give IVF
- oliguria: <0.5ml/kg/hr
- SBP/respiration variation >10mmHg (pulsus paradoxes)
A young healthy pt may lose 20% of circulating blood volume without clinical signs. Why is this?
Vessels can squeeze really tight, and heart can pump really hard to compensate
What are indications for a blood transfusion?
- primary indication is to increase O2 carrying capacity of blood
- justified when Hg <6G/dL
- CAD with acute anemia may transfuse <10g/dL
How is acute hemorrhage managed?
- when blood loss >1/3 entire blood volume —> give blood, not fluids
- if blood loss causes hypovolemic shock , give blood
- whole blood is preferred
What is the major risk of a transfusion reaction?
- incompatibilities to A, B antibodies, A, B, Rh antigen cause cause rapid hemolysis.
What is cross matching?
Incubating recipients plasma with donors RBCs
Takes about 45 min to complete
Emergency transfusions use O negative PRBCs. Why?
- lacks a, b, Rh antigens
- will no be hemolysis by anti-a or anti-b antibodies that may be in the pts blood
What is a risk of transfusing large amounts of O negative blood?
You have now changed their blood type.
—> now if you give their blood type it may react
* get type and crossed blood ASAP instead of running O -neg blood for a long time
What is type specific blood?
- 1st phase of crossmatch done- only tests for a,b, Rh antigens
- chance of significant reaction is 1:1000
- used only in emergency situations
What is a type and screen?
- typed for a,b,Rh antigens, plus screened for most common antibodies
- patients blood is NOT matched to donor unit-
- allows for a unit of blood to be available for more than 1 pt
- ordered for surgical procedures with remote risk of transfusion
—> cross match is done after type and screen - chance of hemolytic reaction is 1:10,000
What preservatives are in stored blood?
- Phos.: buffer
- dextrose: energy to RBCs
- adenine—> to make ATP (adenine triphosphate) for metabolism-increases survival time
How long can blood be stored for and what is the reason for this?
- 21-35 days
- it is required that 70% of RBCs be viable 24 hours after transfusion
What is the volume, Hct, and citrate level of whole blood?
Volume = 450mL
Citrate= 65mL
** Hct= 40% **
What components can be derived from whole blood?
PRBCs Platelets FFP Cryoprecipitate Albumin Plasma proteins fraction Factor VIII Leukocyte poor blood Antibody concentrates
What is the benefit of component therapy?
Allows for specific deficits to be corrected and longer storage time
What are some facts you should know when transfusing PRBCs?
- one unit contains:
Volume = 300mL
Hct = 70% - Hgb should increase 1G/gL per unit PRBCs in 70 kg adult
- when given with hypotonic solution, PRBC swelling and lysis
- if calcium in solution—> clotting
- only infuse with NS *
What are some advantages of using PRBCs?
- decreases potential for citrate toxicity compared to whole blood
- decreases risk for allergic reaction
When is a platelet transfusion indicated?
- platelets <50,000 cells/mm^3
- with trauma or bleeding into brain, eye, airway a higher threshold may be used
- platelet count should increase 5-10,000 cells/mm^3 in 70kg adult
What are risks of platelet transfusion?
- viral disease transmission
- human leukocyte antigens present on platelet cell membrane
- bacterial infection in 1:12,000 transfusions
- small risk of sepsis
What is in FFP?
- contains all plasma proteins
- all coagulation factors except platelets
- factor V and VIII
When is FFP indicated?
- Pt/Ptt > 1.5 xs normal and clinical indication of transfusion
- reversal of warfarin
- correction of known factor deficiency (von Wilderbrans)
What is in cryoprecipitate?
High concentrations of:
- factor VIII and XIII
- von Wildebrans
- fibrinogen and fibronectin
Which component has the highest amount of von Wildebrand factor?
FFP has the highest total amount
While cryoprecipitate has the higher concentrated amount
When is cryoprecipitate indicated?
- factor VIII deficiency (hemophilia A)
- von Willdebrands factor deficiency
- fibrinogen deficiency
During MTP what is the ratio of PRBC:FFP:Platelets?
4:1:1
What are the 3 types of transfusion reactions?
Febrile
Allergic
Hemolytic-life threatening
What happens during a febrile transfusion reaction?
- antibodies react with antigens
** most frequently occurring reaction * - s/s:
Fever
Chills
HA
Myalgias
Nausea
Productive cough
*typically not life threatening *
What is the treatment for a febrile transfusion reaction?
- check pt’s serum and urine for hemolysis (r/o hemolytic reaction)
- slow down the rate and give anti-pyretics
What is happening during an allergic transfusion reaction?
- incompatible plasma proteins in donor blood
- s/s:
Urticaria (rash on chest, seen first)
Pruritis
Occasional facial swelling
What is the treatment for an allergic transfusion reaction ?
- Stop transfusion
- Make sure its not a hemolytic reaction by checking urine and plasma for free Hgb
- Administer IV antihistamine (Benadryl)
What is a hemolytic transfusion reaction?
STOP TRANSFUSION IMMEDIATELY
- from giving erroneous blood to pt
- recipients antibodies attack donor blood
- as little as 10mL blood can result in fatal hemolytic reaction
- severity is proportional to volume transfused
- may result in renal failure and DIC
What are s/s hemolytic transfusion reaction?
Fever Chills CP Hypotension Nausea Flushing Dyspnea Hemoglobinuria (red urine) ** anesthetics mask all s/s but hypotension and hemoblobinuria
What labs results will be seen in a hemolytic transfusion reaction?
- Dx made by direct antiglobulin test
- draw: plasma and urine Hgb, billirubin
- billirubin peaks 3-6 hrs after start of transfusion
What is the treatment for hemolytic transfusion reaction?
- stop transfusion **
- Prevent renal failure by giving enough fluids to maintain UOP @ 100mL/hr by running LR and giving Mannitol or lasix
- give bicarbonate to alkalize the urine and stop crystal ppt
- labs: [Hgb], baseline coags, urine
- return blood to lab with repeat crossmatch from pt
What types of metabolic abnormalities can occur from blood therapy?
- elevated H+ and K+—> body compensates—> become alkalotic
- decreased 2.3 DPG
- decreased Ca—> citrate binds free Ca
- all of these potentially result in a left shift—> leads to tissue hypoxia
(Typically not seen, but theoretical)
The pH of stored blood is 7.1-6.9 d/t increased levels of CO2 in stored blood. Why does it not make your blood acidic?
Recipient eliminates CO2 via the lungs
Citrate metabolizes to bicarbonate upon transfusion
How much K+ is in a unit fo blood?
20-30mEq/L
Usually insignificant until large volumes transfused and pt has underlying dz (renal)
Why is hypocalcemia observed with blood therapy and how is it treated?
- citrate binds to Ca in plasma
- worse with hypothermia, liver disease and hyperventilation
- rarely requires tx
Give 1 G Ca Cl IV or 3 G calcium gluconate
What are the viruses transmitted by blood therapy?
- HIV—>1:1 million
- hepatitis—> 1:60,000
- cytomegalovirus
What are microaggregates?
From stored whole blood —> platelets and leukocytes
- concern they will accumulate in the lungs and obstruct vasculature causing ARDS
- prevention:
- transfuse whole blood through a fine filter (10-40 nm diameter) ( standard filters are 170nm diameter, much larger)
What happens with hypothermia with blood therapy?
- erratic EKG, cardiac irritability
- post op shivering—> increases myocardial demand
—> run blood through a warmer
What are coagulation disorders with blood therapy?
- dilutional thrombocytopenia
- s/s:
Frank bleeding without clotting at surgical site
Hematuria
Spontaneous oozing from puncture sites
What do you need to know about DIC?
- causes:
- significant tissue damage with release of toxins
- large amount of transfused blood
LABS: - prolonged PT and PTT
- decreased fibrinogen
- increased fibrin split products
TREATMENT: - treat underlying cause
- give FFP and platelets
What is TRALI?
- occurs within 6 hours
- acute non cardiac pulmonary edema
- supportive treatment
- most spontaneously recover
What is immunosuppression with blood therapy related to?
- r/t volume of plasma ( whole blood > immonusupression than PRBCs)
- beneficial in transplant pts
- bad with malignancy
What happens with autologous blood transfusion?
- pt donates own blood weeks prior to surgery
- decreased risk of complications
- consider when significant surgical blood loss anticipated
(Still stored blood so have those risks)
What is itraoperative salvage?
Considered when blood loss expected from a CLEAN WOUND
- Contradinicated:
- malignancy
- blood borne diseases
- bowel content contamination
What is the make up of cell saver blood?
Hct= 50-60%
PH is alkaline—> CO2 hasn’t had a chance to build up yet
- only returning PRBCs
What are complications of intra- op salvage?
- dilutional coagulopathy
- mixed with heparin so anticoagulation can occur
- hemolysis
- air/fat embolism
- sepsis
- DIC
What is the hemodilution technique?
Removed pts blood the same day as surgery and store it
- transfuse after major blood loss over
- replace lost volume with IVFs
- dilutes blood loss during surgery
Contraindicated: anemia, severe cardiac or neuro. Disease
How is EBL replaced?
- crystalloids- 3:1
- colloids and blood- 1:1