Pre-op/Post-op Care Flashcards
what are the H+ and K+ shifts in acidosis and what are the results?
H+ ions move from an area of high conc. (extracellular) to an area of low conc. (intracellular), causes K+ to move out of the cell → thus, acidosis
what are the H+ and K+ shifts in alkalosis and what are the results?
H+ ions move from area of high conc. (intracellular) to an area of low conc. (extracellular), causes K+ to move into the cell → thus, alkalosis is a/w hypokalemia
alkalosis vs acidosis pH?
alkalosis = >7.45
acidosis = <7.35
what are the plasma bicarb levels like for metabolic acidosis?
Plasma HCO3 < normal = metabolic acidosis
what are the plasma bicarb levels like for metabolic alkalosis?
Plasma HCO3 > normal = metabolic alkalosis
metabolic acid-base d/o’s are d/o’s of what?
d/o’s of bicarb
respiratory acid-based d/o’s are d/o’s of what?
d/o’s of CO2
what is respiratory acidosis a result of?
retention of CO2 b/c of pulm. alveolar hypoventilation
what are causes of respiratory acidosis?
Acute Resp. Failure:
- CNS depression (d/t opioids, sedative, trauma, anesthetic)
- Cardiopulmonary arrest
- Pneumonia
- Decr. resp. effort d/t pain from incisions/trauma
- PE, hemorrhoids/pneumothorax
Chronic Resp. Failure:
-Advanced lung disease (ex. COPD) -> results in compensated hypoventilation & is well tolerated
respiratory acidosis is primary when what change occurs?
*Primary if pH and PaCO2 change in opposite directions
what’s the s/s of respiratory acidosis?
Hypercapnia and hypoxia
Restlessness and agitation
Mild HTN
As levels rise → confusion, somnolence, and ultimately coma, cardiac arrest
what’s the tx for respiratory acidosis?
- Remove cause and ensure adequate oxygenation, or mechanical ventilation
- Improve pain control
Do NOT correct too rapidly -> can cause severe dysrhythmias (V-tach)
***DON’T ADMIN BICARB W/OUT TREATING THE CAUSE
when should you NOT administer bicarb in respiratory acidosis?
***DON’T ADMIN BICARB W/OUT TREATING THE CAUSE
what are the 2 major causes of metabolic acidosis?
- Loss of bicarb from extracellular space (normal anion gap - hyperchloremic)
- Incr. metabolic acid load (high anion gap)
what’s the cause of non-anion gap metabolic acidosis?
Lost HCO3 is replaced by Cl- → there’s an accumulation of Cl- conc.
***Occurs acutely w/ GI d/o (diarrhea, external pancreatic fistula)
Occurs chronically w/ renal dysfunctions, ureterointestinal anastomosis, decr. mineralocorticoid activity, use of diuretic acetazolamide, burn patients
what’s the causes of high anion gap metabolic acidosis?
- **MUDPILES
- Methanol, Uremia, DKA, Propylene glycol, Isoniazid/Infection, Lactic Acidosis, Ethylene Glycol, Salicylates (also Rhabdo/renal failure)
- **Lactic Acidosis = MCC
- Occurs w/ shock
- Type A (hypoxia)
- Type B (not hypoxia) - d/t liver failure, renal failure, thiamine ef. ETOH intox, metformin
what does MUDPILES stand for and what does it cause?
Methanol, Uremia, DKA, Propylene glycol, Isoniazid/Infection, Lactic Acidosis, Ethylene Glycol, Salicylates (also Rhabdo/renal failure)
causes high anion gap metabolic acidosis
what’s the MCC of high anion gap metabolic acidosis?
Lactic acidosis
when is metabolic acidosis primary?
*Primary if pH and PaCO2 change in same direction
what’s the s/s of metabolic acidosis?
Resp. compensation occurs w/ both acute and chronic metabolic acidosis
what’s the tx of metabolic acidosis?
Treat and correct the underlying d/o
Hypovolemia must be corrected, bleeding must be stopped, sepsis controlled, and/or cardiac fxn improved to improve tissue perfusion
*Admin of bicarb w/out correcting the underlying problem will not return the pH to normal
what’s the pH and CO2 like in respiratory alkalosis?
Incr. in pH related to a decr. in PaCO2
what’s the cause of respiratory alkalosis?
***Incr. in pH related to alveolar hyperventilation
Common in surgical pts d/t pain (MC in young, not elderly - would cause hypoventilation and respiratory acidosis in elderly)
hypoxia, fever, brain injury, sepsis, liver failure, mechanical ventilation
Compensatory mechanism = renal excretion of bicarb (only w/ acute)
what’s the s/s of respiratory alkalosis?
Paresthesias, carpopedal spasm, Chvostek’s sign
K+, Mg, Ca, Phosphate metabolism are all disturbed
Decr. cerebral blood flow (esp. In acute brain injury, atherosclerosis of cerebral blood vessels)
what’s the tx for respiratory alkalosis if spontaneously breathing?
correct the underlying cause of the hyperventilation
what’s the tx for respiratory alkalosis if mechanically ventilated?
reduce the amount of ventilation
what’s the pH and bicarb like in metabolic alkalosis?
Incr. pH related to a incr. In HCO3 (bicarb)
what’s the MC acid-base d/o in surgical patients?
metabolic alkalosis
what electrolyte abnormalities occur in metabolic alkalosis?
GI and renal losses of K+ and Cl- ions can occur & cause hypochloremic hypokalemic metabolic acidosis
caused by -> ***Vomiting/NG suction (loss of gastric HCl), chronic diarrhea, loop diuretics
what’s the s/s for metabolic alkalosis?
K+ depletion → paralytic ileus, digitalis toxicity, cardiac arrhythmias
what’s the tx for metabolic alkalosis?
Replacement of electrolytes (esp. chloride and potassium) and of fluids specific to the type of loss, and control of ongoing losses
what’s the worst single finding predicting high cardiac risk? how’s it treated?
JVD
-treated w/ ACEIs, BBs, digitalis, and diuretics before surgery
what cardiac pt should avoid surgery and needs further evaluation prior to an elective procedure/
pt with unstable angina
what’s Virchow’s triad?
stasis, hyper coagulability, endothelial injury
what is the MC type of hypo-osmolality w/ hypervolemia?
hyponatremia
what are causes of hyponatremia?
SIADH (increased ADH secretion)
Loss of isotonic fluid d/t GIT d/o (body forced to retain water)
Hyperglycemia (causes cells to release water, diluting Na)
Low blood volume/BP (incr. ADH)
Hypertonic mannitol admin
what are the primary sx’s of hyponatremia?
CNS dysfunction
-muscle cramps/seizures
what are sx’s of untreated severe hyponatremia?
seizures, coma, areflexia,d eath
what’s the tx for hypotonic hyponatremia? (Isovolemic, Hypervolemia, Hypovolemic)
Isovolemic: H20 restriction
Hypervolemia: H2O + Na restriction
Hypovolemic: NS
what’s the tx for hypertonic hyponatremia?
NS until hemodynamically stable → switch to ½ NS
what’s the tx for severe hyponatremia?
Hypertonic saline + Furosemide
when must you be cautious in treating hyponatremia?
if you do it too quickly!!!
-repleting Na too quickly may result in Central Pontine Myelinolysis (demyelination of cells from shrinkage caused by rapid shift of serum Na)
what’s the MCC of hypernatremia?
volume depletion/hypovolemia
what are causes of hypernatremia?
MCC is volume depletion/hypovolemia
diarrhea, burn, DI, hyperglycemia
what are the s/s of hypernatremia?
***Incr. BUN:Cr >20:1 (b/c dehydrated), dry mucous membranes, hypotension
CNS dysfxn: hypertonicity shifts water out of cells → shrinkage of brain cells
-Confusion, lethargy, coma, muscle weakness, seizures
when does severe hypernatremia occur?
Severe hyperNa occurs when person can’t obtain water
what’s the tx for hypernatremia?
D5W IV → monitored every 2 hrs until Na < 145
-Then infusion decr. to 1 mL/kg/hr until Na is 140
Goal is to lower serum Na by 1-2 mEq/L per hr in < 24 hrs (don’t want to lower too quickly)
Caution hyperglycemia
what should you be cautious about when treating hypernatremia?
about causing hyperglycemia b/c giving pt D5W
what’s the tx of Diabetes Insipidus?
Desmopressin (ADH analog)
what are the MC causes of hypokalemia?
Increased urinary/GI losses like:
- ***diuretic therapy
- vomiting, diarrhea
what are other causes oh hypokalemia?
metabolic alkalosis, insulin, hypomagnesemia, hyperaldosteronism (increases K+ excretion from kidneys)
Meds (that cause large shifts of K+ from extracellular to intracellular)
- diuretics (loops & thiazides)
- insulin
when to the s/s of hypokalemia manifest?
when K+ < 3.0 mEq/L
what are the s/s of hypokalemia?
muscle cramps, constipation, T wave flattening, U wave
what’s the tx of hypokalemia?
- **K+ replacement with KCL PO (if possible)
- IV KCl given for rapid tx/severe sx
K sparing diuretics (spironolactone, amiloride)
if hypomagnesemia present, need to give Mg (to correct hypoK)
what can too rapid of IV K+ replacement cause?
hyperkalemia and fatal cardiac arrhythmias
what fluids make hypokalemia worse?
dextrose fluids b/c increases insulin causing more K to go into the cells
what are causes of hyperkalemia?
Decreased renal excretion
Decr. aldosterone (hyperaldosteronism, adrenal insufficiency)
Meds: K supplements, K-sparing diuretics, ACEI/ARBs, digoxin, BBs, NSAIDs
Metabolic acidosis (DKA)*
what are the s/s of hyperkalemia?
cardiac sx’s
- pearked T waves
- prolonged QRS -> sin wave -> arrhythmias (v-fib)
- muscle fatigue
what arrhythmia can develop in hyperkalemia?
v-fib
what’s the tx for hyperkalemia?
IV Calcium gluconate*** (stabilizes cardiac membrane)
Insulin w/ glucose (shifts K+ intracellularly) + bicarb
Kayexalate (enhances GI K+ excretion)
when you have hypomagnesemia, what do you also have?
hypokalemia and hypophosphorus
what are causes of hypomagnesemia?
Malabsorption:
-**ETOHics, Celiac disease, small bowel bypass, diarrhea, vomiting, laxatives
Renal losses (diuretics, PPIs)
what are the 2 MC causes of hypermagnesemia?
Renal insufficiency (decr. Mg excretion)
Increased Mg intake (ex. Overcorrection of hypoMg)
what are the s/s of hypermagnesemia?
muscle weakness, decreased DTRs
prolonged QT/PR and wide QRS
what’s the tx for hypermagnesemia?
IV saline and control MG intake
Calcium Gluconate
diuretics (furosemide) or dialysis
what is the classic cause of hypochloremia?
Classically results from loss of acidic gastric contents → vomiting or NG suction
what are the s/s of hypochloremia?
s/s are those of the accompanying d/o
what’s the tx for hypochloremia?
solutions containing sodium chloride and potassium chloride
what are causes of hypocalcemia?
HypoCa w/ decreased PTH (hypoparathyroidism = MC overall cause)
HypoCa w/ increased PTH (chronic renal disease MC cause, vit d def., hypomagnesemia, hypoalbuminemia)
what are the s/s of hypocalcemia?
prolonged QT interval
Chvostek’s sign, Trousseau’s sign, tetany
how do you dx hypocalcemia?
decreased ionized Ca+ & total serum Ca (<8.5 mg/dL)
what’s the treatment for symptomatic hypocalcemia?
IV Calcium gluconate
what’s the tx for mild hypocalcemia?
PO Ca + vit. D (ergocalciferol, calcitriol)
K+ & Mg repletion may be needed
NEED CORRECTED CA IN PTS W/LOW SERUM ALBUMIN
what’s the MC overall cause of hypocalcemia?
hypoparathyroidism
what’s the MC cause of increased PTH?
chronic renal disease
what’s the MC cause of hypercalcemia?
PRIMARY HYPERPARATHYROIDISM OR MALIGNANCY!
what’s the triad of Primary hyperparathyroidism?
increase Ca, increase PTH, decrease phosphate
what drugs cause hypercalcemia)?
thiazides, lithium
what’s the s/s of hypercalcemia?
Stones (kidney stones)
Bones (painful bones, fx’s)
Abd groan (ileus, constipation*)
Psychiatric moans (weakness, fatigue, AMS, decr. DTRs, depression/psychosis)
EKG: shortened QT, prolonged PR, wide QRS
how do you dx hypercalcemia?
increased ionized Ca & total serum Ca >10 mg/dL
what’s the 1st LINE tx for symptomatic hypercalcemia? others?
IV saline & Furosemide = 1st line tx
Others tx = Calcitonin, Bisphosphonates in severe cases (IV Pamidronate)
what diuretics should be avoided in hypercalcemia?
thiazide durietcs (ex. HCTZ)
what’s the MC cause of hyperphosphatemia?
renal failure (decr. Ca+, incr. Phosphate, incr. PTH)
what’s the s/s of hyperphosphatemia?
soft tissue calcifications
most asx, heart block
what’s the tx for hyperphosphatemia?
Phosphate binders:
-Calcium acetate, Calcium carbonate, Sevelamer
what’s the s/s of hypophosphatemia?
Diffuse muscle weakness, flaccid paralysis (d/t decr. ATP)
what’s the tx for hypophosphatemia?
Treat the underlying cause
Phosphate repletion -> potassium phosphate, sodium phosphate
what’s the MCC of hypotension and low urine output?
loss of intravascular volume (volume depletion)
what’s the most valuable value to dx hypo/hypervolemia?
urine output
what’s the labs for hypovolemia?
increased HR, decreased BP, decreased urine output, increased HCT, increased BUN/Cr
what’s the tx for hypovolemia?
LR or NS
what’s the fluid of choice for blood loss?
LR’s
what type of fluid do you start resuscitation with?
crystalloids
what are crystalloids vs colloids?
crystalloids = LR or NS (isotonic fluids)
colloids = blood (pRBC, FFP), albumin
-have osmotic pull
what are causes of hypovolemia?
bleeding, inflammation (“itits)
what’s the labs like for hypervolemia?
decreased urine output, decreased Hct
what are s/s of hypervolemia?
pulmonary/peripheral edema, ascites, JVD
what are causes of hypervolemia?
CHF, hepatic failure, renal failure
what’s the treatment of hypervolemia?
Less severe → fluid or sodium restriction
More severe → diuresis w/ loop diuretics and replacement of associated K+ losses
what’s the best way to achieve euglycemia?
best by continuous infusion of insulin
what’s the management for pt with DM and on rapid-acting or short-acting insulin and getting surgery?
withheld when pt stops PO intake (midnight before day of surgery)
what’s the management for pt with DM and on Intermediate-acting & long-acting insulin and getting surgery?
administered ⅔ the normal evening dose before surgery & 1/2 the normal morning dose the morning of surgery
what’s the management for pt with DM and on long-acting PO agents and getting surgery?
stopped 48-72 hrs before surgery
what’s the management for pt with DM and on short-acting PO agents and getting surgery?
held night before or day of surgery
what’s the MC cause of increased pulmonary risk for surgery?
smoking
when should pts stop smoking before surgery?
at least 6 weeks
what are the 6 “W’s” of post-op fever?
- Wind (atelectasis, pneumonia)
- Water (UTI)
- Wound (wound infection/surgical site infection)
- Walking (DVT)
- “W” abscess
- “W”onder drugs (anytime other etiologies are ruled out)
and then ***surgical complication
what’s the MC source of post-op fever on POD 1?
Atelectasis
what’s the definition of atelectasis?
alveolar collapse
what are s/s of atelectasis?
- Pain
- Somnolence from analgesic use
- Suppressed cough
- Lack of mobility
- Nasopharyngeal instrumentation
what day of post-op are patients at highest risk of atelectasis and why?
POD 1 (b/c that’s when pain is the highest) and d/t pain & not being able to expand lungs
what surgeries put pts at risk for atelectasis?
abdominal surgery and thoracic surgery
does atelectasis cause fever?
NO! but can lead to pneumonia, which causes fever
how do you prevent atelectasis?
OOB, IS, deep coughing/breathing
what are you worried about atelectasis turning into?
pneumonia
when does pneumonia develop post-op?
POD 3 if atelectasis is not resolved
when does UTI develop post-op? what is it d/t?
POD 2-3
UTI post-op is d/t Foley
when does DVT develop post-op?
POD 5-7
when does wound infection/surgical site infection develop post-op?
if caused by C. perfringes then occurs w/in 24 hrs
or POD 5-7 days
what is the location of a wound infection post-op?
above fascia, below the skin (superficial infection)
when does C. perfringes wound infection develop post-op?
w/in 24 hrs of post-op
what is C. perfringes post-op infection hallmarked by?
foul-grey odor
how many days does it take wound to become air tight?
2 days
how is a post-op wound infection with abscess treated?
I&D to drain all pus out
pack it and change dressings or pack with wick and remove in 48-72 hrs
how is an abscess treated vs cellulitis?
abscess -> I&D
cellulitis -> abx
what is primary intention healing of wounds?
Wounds edges have been apposed (by sutures, wound clips, tapes, or dermal adhesives)
what is secondary intention of healing wounds?
Wounds edges have been left unapposed
Dressing is used to collect wound fluids and help keep the wound from closing prematurely
-Common in the management of an abscess
what are the first cells to enter to begin clotting process?
platelets
what are the 3 phases wound healing?
- Substrate phase (inflammatory)
- Proliferative phase
- Maturation phase (remodeling)
what are the main cells in phase 1 of wound healing (inflammatory phase)?
Polymorphonuclear leukocytes (PMNs) -appear shortly after injury and hang around for 48 hrs
Platelets
Macrophages (main cells involved in wound debridement)
what are the MAIN CELLS involved in wound debridement
Macrophages
how long does phase 1 of wound healing (inflammatory phase) last? what does wound look like during this phase?
4 days
wound is edematous and erythematous and is sometimes hard to distinguish from infection
when does phase 2 (proliferative phase) of wound healing being and how long does it last?
Relatively constant phase and begins when wound is covered by epithelium
Occurs indefinitely until the wound surface is closed by ectodermal elements (epithelium for skin, mucosa in gut)
what is phase 2 (proliferative phase) of wound healing characterized by?
production of collagen in the wound
what are the main cells in phase 2 (proliferative phase) of wound healing?
Fibroblasts
what do the fibroblasts do in phase 2 (proliferative phase) of wound healing?
produce collagen
-Collagen = the principal structural protein of the body
what is phase 3 (remodeling) of wound healing characterized by?
maturation of collagen by intermolecular cross-linking
what occurs in phase 3 (remodeling) of wound healing? how long does this phase take?
Wound scar flattens takes 9-12 months in adults)
in which phase of wound healing is collagen deposited in the wound?
phase 3 - maturation phase (remodeling)
what are the 3 classifications of wound healing?
primary intention, secondary intention, tertiary intention
how does the wound close in secondary intention?
Wound closes by contraction and epithelialization
wound is left open and allowed to heal spontaneously from the edges of the wound
what is tertiary intention of wound healing?
Wound is closed by active means after a delay of days to weeks
when should delayed closures of wounds (tertiary intention) be performed?
if quantitative bacterial count of wound is less than 10^5 organisms/gram of tissue
what is required prior to delayed closure of wounds?
Repeated irrigation, debridement and dressing changes are required prior to closure
what are the 5 classifications of wounds?
clean wound
avulsion injury
abrasion
puncture wounds
crush injury
what is a clean wound?
Relatively new (<12 hrs) with minimal contamination
Clean and debride if necessary then close
what is an avulsion injury?
Skin has been violated by shearing forces and underlying tissue has been undermined and elevated, creating a flap or total loss of skin
what’s the tx for an avulsion injury?
cleaning, debridement of necrotic tissue and closure if appropriate
Suture flap down with absorbable sutures then close wound edges
what’s an abrasion wound?
Superficial loss of epithelial elements with portions of dermis and deeper structures remaining intact
what’s the tx for an abrasion wound?
Only cleansing is required
-Apply a layer of petroleum jelly or antibiotic ointment to prevent dessication (excess dryness)
what’s the tx of puncture wounds?
Generally do not require closure
Examine for foreign bodies
what type of wound SHOULD NOT be closed?
A wound that contains highly virulent Streptococci species should NOT be closed
what nutrition should be considered in the pt in wound healing?
Folic acid
Vitamin K
Vitamin A
what is folic acid critical for in wound healing?
critical in the proper formation of collagen
what is vitamin K essential for in wound healing?
essential for the synthesis of clotting factors (need to prevent hematoma)
what is vitamin A’s role in wound healing?
increases the inflammatory response, increases collagen synthesis and increases the influx of macrophages into the wound
when do you stop anticoags for surgery?
2-4 days prior (if a-fib)
when do you stop anti-platelet (ASA, NSAIDs) drugs for surgery?
7 days prior (b/c platelet half-life is 7 days)
what is functional capacity?
indicator of post-op cardiac complication risk (done pre-op)
expressed in METS (metabolic equivalents)
what does < 4 METS mean?
poor functional capacity
ex. self-care, ability to complete ADLs, vacuuming, walking 2mph, and writing
what does 4-10 METS mean?
moderate functional capacity
ex. ability to walk up flight of stairs, walk 4mph, walk gold f course, doing yard work, cycling
what does 10 METS mean?
excellent functional capacity
ex. jogging, tennis, swimming, skiing
what meds are used to help pts quit smoking before surgery?
- **Bupropion -> block reuptake of DA & NE to reduce reward aspects of cig smoking
- Varenciline (MC adr is nausea)
when is Red blood cell transfusion given to a pt? available as what?
given to raise Hgb in pts with anemia or to replace losses after acute bleeding episodes
available as packed RBCs (preferred) or whole blood
