Heme Part 2 Flashcards

1
Q

What are the perioperative risks and concerns for Thalassemia Major?

A
  • CHF common with severe anemia (might want echo)
  • Cardiac arrhythmias d/t heart failure
  • pt may not tolerate cardiac depression caused by anesthetic agents
  • pts are very sensitive to digitalis
  • hepatosplenomegaly
    • hypersplenism can result in thrombocytopenia and increased risk of infection
  • Coagulopathy- may not be able to use regional
  • Complications associated with high Fe- see other card
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Why might a pt with Thalassemia major be a difficult airway?

A
  • maxillary deformities caused by bone marrow hyperplasia
    • may want to consider awake fiberoptic intubation
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What complications do high Fe levelse from frequent transfusions cause?

A
  • Diabetes
  • adrenal insufficiency- decreased response to vasopressors
  • Liver dysfunction and coagulation abnormalities
    • cirrhosis
  • hypothyroidism and hypoparathyroidism
  • Arrhythmias
  • right sided heart failure- from cirrhosis
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What drugs can induce methemoglobinemia?

Who should you avoid these drugs with?

A
  • lidocaine
  • prilocaine
  • silver nitrate
  • also avoid many antibiotics and vitamin K
  • Avoid these drugs in pts with Hgb M and G6PD deficiency
    • if pt has methemoglobinemia and G6PD deficiency, giving methylene blue is life threatening
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

How is pulse oximetry affected by methemoglobinemia?

A
  • Pulse ox is unreliable- typically reads 85%
    • d/t methemoglobin absorbing red and infrared wavelengts equally, giving 1:1 ratio = 85%
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is emergency treatment of toxic methemoglobinemia?

A
  • Avoid tissue hypoxia and further left-ward shift on oxy-hemoglobin curve
    • O2 herapy
  • 1-2 mg/kg of intravenous methylene blue as a 1% solution in saline infused over 3-5 minutes; may repeat after 30 minutes
  • Art line to measure BP, methemoglobin levels and ABG
  • Correct acidosis
  • monitor EKG for signs of ischemia
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What are some general considerations for anesthetic management of a pt with aplastic anemia?

A
  • Patients might be on immunosuppressive therapy
    • may require stress-dose steroids
  • Reverse isolation d/t thrombocytopenia and risk of infection
  • Prophylactic abx
  • Risk of Hemorrhage (GI and Intracranial)
  • LV dysfunction d/t high output state and fluid overload
    • High output caused by the tissues needing more blood delivery b/c not enough hgb
    • fluid overload ???
  • Co-existing congenital abnormalities
    • franconi anemia- congenital, autosomal recessive; the version seen in peds
    • Cleft palate; cardiac defects
  • May be difficult to crossmatch these patients
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What should you consider preinduction and during induction of a pt with aplastic anemia?

A
  • Consider need for transfusions before induction
  • airway hemorrhage possible with DVL- due to thrombocytopenia
    • avoid nasal intubation or trumpet
  • Regional depends on coagulation, usually not ok
  • Labile hemodynamic response to induction (avoid decreases in CO)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What can you do to best support a pt with aplastic anemia during the maintenance phase of anesthesia?

A
  • PEEP will help reduce how much O2 is required
    • hyperoxia depresses boe marrow
  • Avoid nitrous which also depresses bone marrow
  • Maintain normothermia
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What should you consider during extubation and the post operative period of a pt with aplastic anemia?

A
  • Period with greatest O2 demands
  • monitor coagulation status
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is polycythemia?

What causes it?

What problems does it cause?

When do you treat it and how?

A
  • Polycythemia- high red cell mass and increased Hct
    • increases O2 carrying capacity and blood viscoscity, which decreases tissue perfusion
  • Caused by:
    • reduction in plasma volume (dehydration)
    • production of excess RBC (polycythemia vera)
    • chronic hypoxia- increased release of EPO
    • Increased EPO also caused by renal disease or tumors
  • Increased viscoscity can cause venous/arterial thrombosis leading to CAD, Pulm HTN, CNS disorders
  • Treat by phlebotomy when HCT>55%
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What needs to happen before a pt with Hemophelia A can have surgery?

How is this achieved?

A
  • Factor VIII must be brought near normal (100%) for surgery
  • How?
    • Factor VIII concentrate
    • FFP or cryoprecipitate
    • Desmopression
      • O.3 mcg/kg IV for mild hemophilia A
      • increases factor VIII 3-5x
      • Stimulates release of VW factor and factor VIII comes with it
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What can you give a pt with hemophilia B preoperatively to reduce risk of bleeding?

A
  • Recombinant/purified product of factor IX
    • used to treat minor bleeding episodes or prophylaxis with minor procedures
    • dose 100 U/Kg
    • half life 18-24 hours, repeat 50% or original dose q 12-24 hours
    • risk of increased thromboembolic complications b/c these agents contain activated clotting factors
  • FFP
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

How can you treat a patient with Von Willebrand’s disease to decrease risk of bleeding during surgery?

A
  • Avoid nasal intubations or insertion of nasal trumpets
  • DDAVP therapy- for mild bleeding or minor surgery
    • IV 0.3 mcg/kg diluted to 30-50 ml of saline and infucsed over 10-20 min
    • Intranasal 300 mcg- 100 µL of a 1.5 mg/ml solution to each nostril
    • short lived (12-24 hours); repeat doses cause tachyphylaxis
  • Cryo- more reliable for severe bleeding or surgical prophylaxis
    • contains fibrinogen, vWF, and factors VIII and XIII
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is the absent or defective factor and treatment for the three hereditary coagulation disorders?

(table)

Hemophilia A

Hemophilia B

vWB

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What drugs can cause platelet dysfuntion?

A
  • ASA- irreversible COX inhibitor, inhibits thromboxane A2 which inhibits platelet aggregation
    • bleeding time prolonged 2-3 minutes w/in 3 hours of ASA ingestion
    • lastes lifetime of platelet
    • bleeding time returns to normal within 72 hours but plt aggregation takes 7-10 days
  • NSAIDS- reversibly inhibit platelet COX
  • Antibiotics-
    • PCNS and cephalosporins
    • crinically ill pts at greatest risk
    • interfere with plt adhesion, activation, and aggregation
  • Volume expanders
    • dextran interferes with aggregation
    • Hydroxyethyl starch in excess of 2L
18
Q

What factors besides drugs can cause platelet dysfunction?

How can you treat platelet dysfunction?

A
  • hypothermia (<35 decrees C)
  • Acidosis (pH<7.3)
  • Uremia
  • liver disease- liver produces thrombopoeitin
  • Treatment:
    • desmopressin
    • cryo for vWF
    • platelet transfusion
19
Q

What is normal platelet count?

How many platelets are required for surgery?

What is the threshold for risk of spontaneous bleed?

What is required for neurosurg procedures or neuraxial procedures?

How much should one unis increase plt count?

A
  • Nml = 150,000-450,000
  • plt > 50,000 required for major surgery
  • 20,000-30,000 ok for minor surgery
  • <20,000 is risk for spontaneous bleed
  • 100,000 requried for neurosurg or neuraxial procedures
  • Each unit of apharesis platelets or six units of random donor platelets will increase plt count about 50,000
20
Q

What is the most common cause of intraopterative coagulopathy?

A
  • Dilutional thrombocytopenia and dilution of pro-coagulants
    • blood loss replaced with crystalloid, colloid, and PRBCs which dilutes platelets and factors
  • Must give FFP and consider platelets
21
Q

What can cause a decrease in platelet production?

A
  • Usually results from bone marrow damage
    • radiation
    • chemo
    • exposure to toxic chemicals
    • drugs such as thiazide diuretics, alcohol, and estrogen
    • malignancies
    • viral hepatitis
    • vit B12 or folate deficiencies
22
Q

What is DIC?

A
  • Platelet destruction disorder, associated with:
    • sepsis
    • trauma
    • cancer
    • obstetric complications
    • vascular disorders
    • immunological disorders
  • Excessive deposit of fibrin/impaired fibrin breakdown
  • Platelet consumption
  • depression of normal coagulation mechanisms
  • Causes thrombosis and bleeding
    • micor emboli accumulate in pulm system
    • cause organ damage
23
Q

What labs do you look at to diagnose DIC?

A
  • no single lab test can rule in or out DIC diagnosis
    • Rapid decrease in plt count <50,000
    • prolonged PT, PTT
    • presence of elevated fplit fibrin degradation products (d-dimer)
    • low plasma concentrations of factor VIII
    • decreased fibrinogen levels
24
Q

How is DIC treated?

A
  • manage the underlying clinical issue that triggered the coagulation process
  • transfuse platelets, FFP, CRYO, RBCs if indicated
  • heparin administration to block thrombin formation which blocks consumption of the other clotting factors and allows hemostasis
  • hemodynamic/resp support
25
Q

What does Vit K deficiency cause?

What causes Vit K deficiency?

Treatment?

A
  • Vit K is required for factors II, VII, IX, and X
    • prolonged PT in presence of normal PTT
  • deficiency caused by:
    • malnutrition
    • GI malabsorption
    • antibiotic induced elimination of intestinal flora
    • liver disease/obstructive jaundice
  • Treatment
    • vit K
    • FFP if active bleeding present
26
Q

What are some acquired hypercoagulability disorders?

A
  • malignancies
  • pregnancy
  • oral contraception
  • nephrotic syndrom
  • systemic lupus erythematosus
27
Q

How are hypercoagulation disorders managed regarding anesthesia?

A
  • early ambulation
  • subcutaneous heparin
  • conpression socks
  • ASA
  • vena caval filter
  • hydration
  • Regional anesthesia is beneficial
    • not advised if on LMWH
28
Q

What are anticoagulants used to treat long term?

What problem does this pose for surgery?

A
  • Long term anticoagulants used for
    • venous thrombo embolism
    • hereditary hypercoagulable states
    • cancer
    • mechanical heart valves
    • atrial fibrillation
  • Problem for surgery: the risk of thrombosus vs the risk of surgical bleeding
29
Q

How is coumadin managed around surgery?

What if the patient is high risk without anticoagulation therpay?

A
  • Hold 5 days pre-op
  • measure INR one day preop
    • if INR > 1.8 give 1-2 mg Vitamin K SQ
  • Emergent reversal of coumadin use 5-8 ml/kg FFP
  • High risk without anticoagulation:
    • start IV or SQ heparin 3 days after stopping coaumadin
    • heparin drip must be stopped 6 hours prior to surgery
    • surgery can be performed with INR <1.5
30
Q

Can you do regional with:

LMWH?

ASA/NSAIDS?

Plavix?

SQ heparin?

Coumadin?

A
  • increased risk for sminal hematoma/hemorrhage
  • LMWH- you can do regional 24 hours after last dose
  • ASA/NSAIDS- regional ok as long as no other anticoagulants
  • Plavix- NO regional
  • SQ heparin- give after the regional
  • Coumadin- stop 3-5 days prior