Fluid and Electrolyte Balance

Question 1

Fraction of total body water distributed intracellularly

Answer 1

2/3

1/3 extracellular

Question 2

Extracellular portion of body water is distributed

Answer 2

3/4 interstitial

1/4 intravascular (Plasma)

Question 3

Plasma makes of what percentage of total body water

Answer 3

about 8.3%

Question 4

Calculation for approximate blood volume

Answer 4

TBV = 0.07 x Body weight (kg)

62kg individual has (62 x 0.07 - 4.3 liters blood volume)

Question 5

Total body water calculation

Answer 5

TBW = 0.6 x body weight kg

Question 6

Flow calculation from TBW to ECF to liters of water in interstitial and plasma

Answer 6

TBW = 0.6 x body weight kg

ECF = 1/3 TBW

Interstitial = 3/4 of ECF

Plasma = 1/4 of ECF

Question 7

How does anesthesia affect fluid and electrolyte balance in surgical patients

Answer 7

Anesthesia (esp GETA) causes increased insensible losses (expiratory evaporation / sweating etc)

Question 8

How does the trauma of surgery affect fluid and electrolyte balance

Answer 8

Trauma = inflammation

Inflammation = vasodilation and increased vascular permeability&raquo_space;» “3rd spacing” (interstitial / edema)

Question 9

How does sepsis affect fluid and electrolyte balance

Answer 9

Inflammation / Vasodilation &raquo_space; 3rd spacing

Question 10

Calculation for fluid maintenance requirements

Answer 10

First 0-10 kg = 100 mL/kg/day (10 kg = 1000 mL/day)

Next 10-20 kg = 50mL/kg/day (add 500ml/day)

All subsequent kg = 20mL/kg/day (add 20*__kg)

Question 11

Fluid MAINTENANCE requirements includes what losses

Answer 11

Urinary, Stool, Insensible

Question 12

What needs to be added to maintenance fluid requirements in surgical patients

Answer 12

Losses before or during surgery

Question 13

70kg man needs how much daily maintenance fluid

Answer 13

1st 10kg = 1000 ml
2nd 10kg = 500 ml
Remaining 50 kg = (50 * 20) 1000 ml

2500ml / day = 105ml / hour over 24 hours

Question 14

Aside from weight gain and peripheral edema, 2 signs of volume excess

Answer 14

pulmonary edema

S3 gallop

Question 15

“3rd space mobilization” typically happens at what point after surgery

Answer 15

Post-op day 3

Question 16

Over what period of time should fluid abnormalities be corrected

Answer 16

Over 24 hours - don’t go too fast

Question 17

Fever of what degree is common after surgery

Answer 17

< 101.3F (38.5C)

Question 18

DDXof postop fever

Answer 18

Wind - atelectasis (early) pneumonia (later) POD 1-3

Water - UTI, anastomotic leak POD 3

Wound - wound infection, abscess (POD 5)

Walking - DVT / PE POD 7

Wonderdrug or What did we do? - can be any time - many drugs / blood transfusions can cause fever. Central lines can cause sepsis.

Question 19

Most early postop fevers are ____ except _____

Answer 19

noninfectious, necrotizing fasciitis

Question 20

How to differentiate pneumonia from atelectasis

Answer 20

Pneumonia typically develops later on post op

Look for sputum, elevated WBC, temp curve progressing upward

• *Atelectasis will usually be BILATERAL**
• *Pneumo will usually be UNILATERAL**

Question 21

When evaluating postop fever, 4 things that could kill your patients which should always be considered

Answer 21

1. Necrotizing fasciitis
2. Malignant hyperthermia (fast rise in body temperature and severe muscle contractions when someone with the disease gets general anesthesia)
3. Anastomotic leak (GI) - place a drain or return to OR
4. Allergic rxn to abx or transfusion
   * look for hypotension, rash*

Question 22

Med used to treat malignant hyperthermia

Answer 22

Dantrolene IV

Question 23

Initial assessment for post op fever

Answer 23

1. To bedside, CBC + vitals
2. History. If worrisome, AMPLE history
3. Physical:
   #1 check the wound or surgical site
   #2 lung sounds, heart/abd/extremity exam
   #3 check IV sites, central line, Foley, tubes

Question 24

Important history questions while assessing post op fever

Answer 24

Type of surgery,

meds or blood given,

other symptoms (rash, cough, dyspnea, chest pain, dysuria, leg swelling, painful IV site, abd pain)

Question 25

3 must - dos for Physical exam in postop fever

Answer 25

#1 check the wound or surgical site
#2 lung sounds, heart/abd/extremity exam
#3 check IV sites, central line, Foley, tubes

Question 26

Daily fluid loss is via urine ____ stool ____ and skin ____ and lungs ____

Answer 26

(1,200 ml),

(200 ml)

(400 ml)

(200 ml)

Question 27

“Normal” person consumes ___ ml fluid / day

Answer 27

2,000ml (1500 fluids, 500 from solid food)

Question 28

Amount of protein needed / day for adequate wound healing

Answer 28

1gm of protein / kg / day