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Flashcards in Fluid and Electrolyte Balance Deck (28):

Fraction of total body water distributed intracellularly


(1/3 extracellular)


Extracellular portion of body water is distributed

3/4 interstitial
1/4 intravascular (Plasma)


Plasma makes of what percentage of total body water

about 8.3%


Calculation for approximate blood volume

TBV = 0.07 x Body weight (kg)

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


Total body water calculation

TBW = 0.6 x body weight kg


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

TBW = 0.6 x body weight kg

ECF = 1/3 TBW

Interstitial = 3/4 of ECF

Plasma = 1/4 of ECF


How does anesthesia affect fluid and electrolyte balance in surgical patients

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


How does the trauma of surgery affect fluid and electrolyte balance

Trauma = inflammation

Inflammation = vasodilation and increased vascular permeability >>>> "3rd spacing" (interstitial / edema)


How does sepsis affect fluid and electrolyte balance

Inflammation / Vasodilation >> 3rd spacing


Calculation for fluid maintenance requirements

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)


Fluid MAINTENANCE requirements includes what losses

Urinary, Stool, Insensible


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

Losses before or during surgery


70kg man needs how much daily maintenance fluid

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

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


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

pulmonary edema

S3 gallop


"3rd space mobilization" typically happens at what point after surgery

Post-op day 3


Over what period of time should fluid abnormalities be corrected

Over 24 hours - don't go too fast


Fever of what degree is common after surgery

< 101.3F (38.5C)


DDXof postop fever

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.


Most early postop fevers are ____ except _____

noninfectious, necrotizing fasciitis


How to differentiate pneumonia from atelectasis

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**


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

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*


Med used to treat malignant hyperthermia

Dantrolene IV


Initial assessment for post op fever

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


Important history questions while assessing post op fever

Type of surgery,

meds or blood given,

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


3 must - dos for Physical exam in postop fever

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


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

(1,200 ml),

(200 ml)

(400 ml)

(200 ml)


"Normal" person consumes ___ ml fluid / day

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


Amount of protein needed / day for adequate wound healing

1gm of protein / kg / day