Anemia

Question 1

O2 content calculation

Answer 1

CaO2= (Hgb x 1.39)SaO2 + PaO2 * 0.003

Question 2

Chronic Anemia Anesthetic Goals:

Answer 2

Avoid disruption of compensatory mechanisms
Maximize O2 deliver; give O2 and PEEP
Avoid drug-induced decreases in CO
Volatile anesthetic effects will be accelerated (dec solubility of blood)
Avoid conditions that favor leftward shift (hyperventilation/alk; hypothermia)

Question 3

Compensatory mechanisms for chronic anemia

Answer 3

increased: CO, 2,3-DPG; P-50; plasma volume;
decreased: blood viscosity, SVR
RIGHTward shift
Redistribution of blood to organs with higher extraction ratio

Question 4

Anesthetic management in Folic Acid Deficiency

Answer 4

avoid regional and PNB (neuropathies)
Avoid N2O
Maintain PaO2
Assess airway- smooth tongue

Question 5

Hemolytic anemia anesthetic management

Answer 5

Increased risk of tissue hypoxia
splenectomy increases infection risk
erythropoeitin prescribed 3 days prep
Acute drops below 8 and chronic below 6 considered for transfusion
preoperative hydration and caution METHYLENE BLUE
increased risk of venous thrombosis (increased coag)

Question 6

Thalassemia considerations

Answer 6

Coagulopathy (question regional)
Hypersplenism (thrombocytopenia and increased risk of infection)
MAXILLARY DEFORMITIES
Complications of iron loading: Diabetes, adrenal insufficiency, liver dysfunction and coagulation abn; hypothyroid/parathyroidism; arrythmias; right sided heart failure
Spinal cord compression
HR- watch arrythmias

Question 7

Aplastic anemia considerations

Answer 7

steroid stress dosing (pts on immunosup)
reverse isolation; prophylactic antibioitics
hemorrhage possible with DVL; consider transfusions before
difficulty crossmatching blood
regional anesthesia (caution bleeding epidural hematoma)
Avoid N2O
Use PEEP to facilitate decreased FIO2 (BMS)

Question 8

Sickle Cell considerations

Answer 8

1. HYPOXEMIA 2. HYPOVOLEMIA 3. STASIS

transfusion goal to decrease Hgb S to

Question 9

Hemophilia A; what level is low? and what is treatment?

Answer 9

VIII
Infusion of Factor VIII; 50-60 U/kg , repeated infusion 25-30 U/K every 8-12 hours. 
Continue for 2 weeks
 Keep plasma factor VIII level above 50%
half life is 12 hours

Question 10

Hemophilia B: what is low, and what is treatment?

Answer 10

Factor IX; dose 100 U/kg; repeat 12-24 hrs at 50 U/kg.

(Increased risk of thromboembolic complications, can activate other clotting cascades

Question 11

Hemophilia A anesthetic management

Answer 11

risk of bleeding with regional (contraindicated)
careful DVL
avoid IM

Question 12

Von Willebrand’s disease anesthetic considerations and treatment:

Answer 12

avoid nasal intubations/trumpets
DDAVP for mild bleeding/surgery: 0.3 mcg/kg (in 30-50mL) over 10-20 min.
Cryoprecipitate for severe bleeding or prophylaxis: contains fibrinogen, VWF, VIII, XIII

Question 13

Factors that cause platelet dysfunction:

Answer 13

Hypothermia, acidosis, uremia

Treatment: cWF in cryoprecipitate, desmopressin, platelet transfusion

Question 14

Treatment for methemoglobinemia:

Answer 14

influences the accuracy of pulse oximetery as methemoglobin absorbs light equally in both red and infrared.
O2 therapy
1-2 mg/kg of intravenous methylene blue as a 1% solution in saline infused over 3-5 minutes (may be repeated after 30 mins)

Question 15

Factors interfering with O2 delivery to tissues

Answer 15

decreased CO

LEFTWARD shift of curve: respiratory alk; hypothermia; abnormal Hgb (fetal Hgb and carboxyhemoglobin)