Lecture 5 IV Fluid and Blood in the Perioperative Period

Question 1

What percentatge of body weight in males is water? Females?

Answer 1

Total Body Water=60% of body weight in males and 55% of body weight in females. Up to 80% body weight in infants. Less in obese; fat contains little water

Question 2

How much of total body water is intracellular?

Answer 2

two thirds

Question 3

How much of total body water is extracellular?

Answer 3

one third

Question 4

Of the extracellular water, how much is intravascular?

Answer 4

1/4-1/3

Question 5

What is the approximate intravascular volume of a 60 kg female?

Answer 5

3.8 L

Question 6

What is the approximate intravascular volume of a 70 kg male?

Answer 6

5 L

Question 7

What factors can be used to preopratively assess fluid status?

Answer 7

mental status, h/o intake and output, blood pressure: supine and standing, heart rate, skin turgor, urinary output, serum BUN/osmolarity

Question 8

Orthostatic hypotension is defined as….

Answer 8

systolic blood pressure decrease of >than 20 mm Hg from supine to standing (10% decrease normal 12-20% is borderline)

Question 9

What percentage fluid deficit is indicated by orthostatic hypotension?

Answer 9

6-8%

Question 10

In the presence of orthostatic hypotension, a failure of heart rate to increase may indicate….

Answer 10

autonomic dysfunction or antihypertensive drug therapy (beta-blockers)

Question 11

What factors must you consider for perioperative fluid requirements?

Answer 11

maintenance fluid requirements, compensatory fluid bolus, NPO and other deficits: NG suction, bowel prep, Third Space losses, replacement of blood loss, special additional losses

Question 12

How do you calculate maintenance fluid requirements?

Answer 12

1.5 ml/kg/hr for adults or 4:2:1 rule (4 ml/kg/hr for the 1st 10 kg of body weight, 2 mL/kg/hr for 2nd 10 kg, 1 mL/kg/hr for every kg thereafter)

Question 13

How much is a customary compensatory fluid bolus early in anesthetic?

Answer 13

500 mL in 70 kg patient

Question 14

How much fluid should be given to compensate for a bowel prep?

Answer 14

1 L

Question 15

NPO deficit is calculated by…

Answer 15

number of hours NPO x maintenance fluid requirement (but usually start the hours at wake up time)

Question 16

How do you calculate third space losses for superficial surgical trauma?

Answer 16

1 ml/kg/hr

Question 17

How do you calculate third space losses for minimal surgical trauma (head and neck, hernia, knee surgery)?

Answer 17

2 ml/kg/hr

Question 18

How do you calculate third space losses for moderate surgical trauma (hysterectomy, pelvic surgery)?

Answer 18

3 ml/kg/hr

Question 19

How do you calculate third space losses for major surgical trauma (major intestinal surgery, major orthopedic procedures, open abdominal aortic aneurism repair)?

Answer 19

4 ml/kg/hr

Question 20

How much blood loss can be ignored before replacing with fluids?

Answer 20

1.5-2 cc/kg

Question 21

Blood loss after 1.5-2 cc/kg should be replaced with crystallod at a ratio of? With colloid?

Answer 21

3:1 crystalloid, 1:1 colloid

Question 22

Hetastarch has what adverse effect?

Answer 22

mild coagulopathy when used over certain doses, rare allergic reactions. Can also elevate serum amylase

Question 23

Hypertonic saline solutions may be used for…

Answer 23

cerebral edema. Draws water out of cells

Question 24

How is oxygen delivery calculated?

Answer 24

oxygen delivery (DO2) = oxygen content (CaO2) x Cardiac Output (CO)

Question 25

What is the main determinant of oxygen content in the blood?

Answer 25

hemoglobin

Question 26

How is cardiac output calculated?

Answer 26

CO = HR x SV

Question 27

How is oxygen content calculated?

Answer 27

Hgb x 1.39 x O2 Sat + PaO2 x 0.003. If PaO2=100, Hgb=15, and O2 sat 1, 0.3 ml O2/dl blood

Question 28

What is the transfusion trigger?

Answer 28

Think oxygen delivery. Tolerance of acute anemia depends on: maintenance of intravascular volume, ability to increase cardiac output, increases in 2,3 DPG to deliver more of the carried oxygen to tissues.

Question 29

What is cross matching blood?

Answer 29

major: donors erythrocytes incubated with recipients plasma, minor: donor’s plasma incubated with recipient’s erythrocytes. Blood unit is reserved for that patient, but can be re-matched for another patient

Question 30

What is the difference between a type and screen and a type and cross?

Answer 30

Type and screen is a test done on the patient in which the recipient blood has been tested for ABO/Rh antigens and screened for common antiboides (not mixed with recipient blood). Blood is not reserved. In a type and cross, blood is reserved

Question 31

What is type specific transfusion?

Answer 31

Only ABO-Rh is determined

Question 32

If you don’t have time but must transfuse blood, what do you give?

Answer 32

O Rh negatve packed cells

Question 33

What are the blood components as divided for transfusion?

Answer 33

packed red blood cells, platelet concentrate, fresh frozen plasma, cryoprecipitate, albumin, plasma protein fraction, leukocyte poor blood, factor VIII, antibody concentrates

Question 34

1 unit of pRBC’s raises the Hgb….

Answer 34

1 gm/dL

Question 35

Why can’t you use LR when transfusing pRBC?

Answer 35

LR has calcium which may cause clotting if mixed with pRBC

Question 36

What is contained in fresh frozen plasma?

Answer 36

coagulation factors except platelets

Question 37

What are the types of transfusion reactions?

Answer 37

febrile, allergic, hemolytic

Question 38

What are the complications of blood therapy?

Answer 38

transfusion reactions, transmission of viral diseases, decreased 2,3 DPG, citrate (calcium binding, metabolism to bicarb), hypothermia, microaggregates, coagulation disorders (massive transfusion may lead to dilution of platelets and factor V and VIII)

Question 39

How do you get autologous blood for transfusion prior to surgery?

Answer 39

1 unit donated every 7 days (up to 4 units) last unit donated >72 hrs prior to surgery

Question 40

What are alternatives to blood products?

Answer 40

hematopoetic growth factors, isovolemic hemodilution, surgical technique, intra-operative blood salvage, coagulants, blood substitutes, hyperbaric oxygen therapy