Intro to Surgery Flashcards
Define elective surgery
Non-emergent surgery which is scheduled at least 24 hours in advance
Define emergent surgery
Surgery for a condition which is immediately life-threatening. This term implies that surgery must be performed within a few hours (time frame varies)
What are some examples of preparations that can greatly improve the outcome of a surgery?
Appropriate pre-op medications (i.e. abx) Cardiac optimization Pulmonary optimization Empty stomach Bowel preparation
How far in advance of surgical incision is administration of abx recommended?
1 hour
Why is it optimal for a patient to have an empty stomach prior to surgery?
Decreases the likelihood of aspiration PNA
Elevated intra-abdominal pressure and delayed gastric emptying increase the risk for what to occur?
Increase aspiration risk
What are some examples of conditions that elevate intra-abdominal pressure and thus decrease stomach emptying?
Morbid obesity and pregnancy
What are some examples of conditions that delay gastric emptying and thus decrease stomach emptying?
Gastroparesis, pregnancy, abd trauma
How long does it take for clear liquids to clear the stomach (the “minimum fasting period” should be…)
2 hours
How long does it take for breast milk to clear the stomach (the “minimum fasting period” should be…)
4 hours
How long does it take for infant formula to clear the stomach (the “minimum fasting period” should be…)
4 hours (<3 months), 6 hours (> 3 months)
How long does it take for nonhuman milk to clear the stomach (the “minimum fasting period” should be…)
6 hours
How long does it take for a light meal to clear the stomach (the “minimum fasting period” should be…)
6 hours
Why would a patient need a preoperative bowel prep?
Decreases abdominal contamination in the event of bowel entry
Total body water is distributed with about ____% intracellular and ____% found in extracellular spaces. The extracellular portion is ____% interstitial and ____% intravascular/plasma.
66%; 33%
75%; 25%
Plasma volume = ____(fraction), or about ____%, of TBW (total body water).
1/12; 8.3%
Intravascularly, in addition to plasma, there are also formed elements such as ___, ___, and ___
RBCs, WBCs, and platelets
TBV = ___% x Body Weight (kg)
7%
____ ____ is the fluid excreted by cells
Transcellular water
1 L water weighs ____ kg
1 kg
Why are we so concerned about surgical pt’s fluid and electrolyte imbalance?
They cannot eat/drink Anesthesia Postop fever Surgical/pre-surgical trauma Sepsis
Sepsis causes (vasodilation/vasoconstriction)
Vasodilation
Anesthesia (especially GETA) causes increased ___(organ system)____ insensible loss
Pulmonary
Postop fever will (decrease/increase) insensible losses
Increase
Surgical (or pre-surgical) trauma affects distribution of body fluid from ______ to _____ spaces
Vasculature to extracellular “third space” (intercellular space)
What are some possible mechanisms/pathways for insensible losses?
Evaporation, condensation, sweat, stool
During and after a surgery, a pt is going to be in need of a lot of “replacement”–what needs replacing?
Fluid replacement (maintenance, ongoing, and any pre-existing volume deficits) Electrolyte replacement (any pre-existing electrolyte deficits)
How much fluid is required when considering the first 0-10 kg of body weight? The next 10 kg? For all subsequent kg of body weight (>20kg)?
100 mL/kg/day
50 mL/kg/day
20 mL/kg/day
What would the appropriate daily maintenance volume be for a 70 kg man who is NPO after surgery? Distributed over 24 hours?
1st 10 kg x 100 ml = 1000ml
2nd 10 kg x 50 ml = 500ml
Next 50 kg x 20 ml = 1000ml
TOTAL = 2500 ml/d
Distributed over 24 hours:
105 ml/hour
As patients become heavier than optimal body weight, IVF rates require adjustment according for ____ and ____.
BMI and BSA (body surface area)
In patients with compromised pulmonary, cardiac or renal function, what should be done in regards to their fluid replacement?
Run them “dry” for a longer period of time, to minimize fluid overload (CHF, pulmonary edema, etc)
What is the best way to monitor fluid status in a pt?
Measure urine output
For maintenance, you should administer Na+ at ____ mEq/kg/day and K+ at _____ mEq/kg/day
Na+ = 1-2 mEq/kg/day K+ = 0.5 - 1 mEq/kg/day
Why should you always give K+ with care, in a slow infusion, never as a bolus?
It HURTS!
T/F Ca++, PO4–, Mg++ are often not required for short term electrolyte replacement
True
Na 130, K+ 4, Cl 109, Bicarb 28, Ca2+ 2.7 is the composition of what replacement fluid?
Lactated Ringers (LR)
Na 154, Cl 154 is the composition of what replacement fluid?
0.9% Normal Saline (NS)
D5 1/2 NS is the composition of what replacement fluid?
Dextrose
D5 1/2 NS is the composition of what replacement fluid?
Fluids with dextrose
In addition to insensible losses, what are other reasons that operative pts may lose fluids ongoing?
NG tube Evaporation via open incision Operative bleeding Third space losses Drains Fistulae Burns