Preop Flashcards
Ejection fraction______ (normal 55%) poses prohibitive cardiac risk for elective non-cardiac operations
<35%
In pts with EF of less than 35%
Incidence of peri-operative myocardial infarction (MI) could be as high as
75-85%, and mortality for such an event as high as 50–90%.
___________, which indicates the presence of CHF, is the worst single finding predicting high cardiac risK
Jugular venous distention
__________is the next worse predictor of cardiac complications. Operative mortality within 3
months of the infarct is 40%, but drops to 6% after 6 months
Recent MI
Smoking is by far the most common cause of increased pulmonary risk, and the problem is
compromised ___________
ventilation (high Pco2, low forced expiratory volume in 1 second [FEV1]), rather than compromised oxygenation
Cessation of smoking for _________weeks and intensive respiratory therapy (physical therapy,
expectorants, incentive spirometry, humidified air) should precede surgery
8
Severe nutritional depletion is identified by one or more of the following:
- Loss of 20% of body weight over 6 months
- Serum albumin <3 g/dL
- Anergy to skin antigens
- Serum transferrin level <200 mg/dl
Features of malignant hyperthermia
Temperature >104°F and metabolic acidosis, hypercalcemia, and hyperkalemia also occur
Postoperative fever 101–103° F is caused (sequentially in time) by 1 2 3 4 5
atelectasis, pneumonia, UTI, deep venous thrombophlebitis, wound infection, or deep abscesses
Cause of fever on D3 PO
Pnx and UTI
Deep thrombophlebitis typically produces fever starting around __________
post-operative day 5.
Wound infection typically begins to produce fever around post-operative _________
day 7.
Post op MI MR
Mortality is 50-90%and
greatly exceeds that of MI not associated with surgery
typically occurs around post-operative day 7 in elderly and/orimmobilized patients.
The pain is pleuritic, sudden onset, and is accompanied by shortness of breath
PE
PE ABG
hypoxemia and often hypocapnia.
If a PE recurs while anticoagulated or if anticoagulation is contraindicated, place_________
an inferior vena cava (Greenfield) filter to prevent further embolization from lower extremity deep venous thromboses
____________ can develop in patients with traumatized lungs once they are subjected to positive-pressure breathing.
Intraoperative tension pneumothorax
________ is the first suspect when a post-operative patient becomes confused and disoriented.
________ is another prime cause
Hypoxia
Sepsis
Adult respiratory distress syndrome (ARDS) is seen in patients with a complicated post-op
course, often complicated by ________ as the precipitating event
sepsis
DT happens on what day post op?
Delirium tremens (DTs) is very common in the alcoholic whose drinking is suddenly interrupted
by surgery. During post-operative day 2 or 3, the patient gets confused, has hallucinations,
and becomes combative
mortality is high, especially in
young women; the best management is prevention by including sodium in IV fluids
Acute hyponatremia
Surgical damage to the posterior pituitary with
unrecognized diabetes insipidus is a good example causing this
Hypernatremia
____________ is a common source of coma in the cirrhotic patient with bleeding
esophageal varices who undergoes a portocaval shunt
Ammonium intoxication
Low urinary output (<0.5 ml/kg/hr) in the presence of normal perfusing pressure (i.e., not
because of shock) represents either ______ or ______
fluid deficit or acute kidney injury
How to test perfusion in pts with low UO?
A low-tech diagnostic test is a fluid challenge: a bolus of 500 ml of IV fluid infused
over 10 or 20 minutes. Dehydrated patients will respond with a temporary increase in
urinary output, whereas those in renal failure will not do so
A more scientific test for hyponatremia is to measure urinary sodium: it will be__________ in the
dehydrated patient with normally functional kidneys, while it will exceed _________ in cases of renal failure
<10 or 20 mEq/L
40 mEq/L
In order to calculate the FeNa, plasma and urinary sodium and creatinine must be measured. In acute kidney injury, the ratio______; in hypovolemia it is______
> 2
<1.
Early mechanical bowel obstruction because of_______can happen during the postoperative period.
What was probably assumed to be paralytic ileus not resolving after ____ days is most likely an early mechanical bowel obstruction
adhesions
5-7
______________or pseudo-obstruction is a poorly understood (but very common) condition
that could be described as a “paralytic ileus of the colon.”
Ogilvie syndrome
Usual pts where Ogilvie syndrome is common
It does not follow abdominal surgery but is classically seen in elderly sedentary patients (Alzheimer, nursing home) who have become further immobilized owing to surgery elsewhere (broken hip, prostatic surgery).
Wound dehiscence is typically seen around post-operative day 5 after open laparotomy. The wound looks intact, but large amounts of pink, “salmon-colored” fluid are noted to be soaking the dressing; this is_________
peritoneal fluid.
Mx of wound dehiscence
Reoperation is needed to avoid peritonitis and evisceration
________ is a catastrophic complication of wound dehiscence, where the skin itself opens
up and the abdominal contents rush out
Evisceration
Fistula of the GI tract
If it does not empty completely to the outside but leaks into a cavity which then leaks out, what will develop?
an abscess may develop and lead to sepsis; complete drainage is the required treatment
What is needed to keep the patient alive until nature heals the fistula?
Fluid and electrolyte replacement, nutritional support (preferably elemental diets delivered beyond the fistula), and compulsive protection of the abdominal wall (frequent
dressing changes, suction tubes, “ostomy” bags)
Every 3 mEq/L that the serum sodium concentration is >140 represents roughly ___________
1 L of water lost.
IVF to correct hypernatremia
This is achieved by using D51⁄2 NS
rather than D5W
If the hypernatremia develops rapidly (i.e., in osmotic diuresis, or diabetes insipidus),
it will produce CNS symptoms (the brain has not had time to adapt), and correction can be safely done with more diluted fluid _________
(D51⁄3 NS, or even D5W).
patient who starts with normal fluid volume adds to it by retaining water because of the presence of inappropriate amounts of ______________
ADH (e.g., post-op water
intoxication, or inappropriate ADH secreted by tumors).
Another scenario for hyponatremia
In the other scenario, a patient who is________________ if he has not received appropriate replacement with isotonic fluids
losing large amounts of isotonic fluids (typically
from the GI tract) is forced to retain water
In the case of the hypovolemic, dehydrated patient losing GI fluids and forced to retain water, volume restoration with _____________ will
provide prompt correction of the hypovolemia
isotonic fluids (NS or Lactated Ringer’s)
Remember that the safe “speed limit” of IV potassium administration is ________
10 mEq/hr.
The ultimate therapy for hyperkalemia is hemodialysis, but while waiting for it we can help by “pushing potassium into the cells” (\_\_\_\_\_\_\_\_\_), sucking it out of the GI tract (NG suction, \_\_\_\_\_\_\_\_\_), or neutralizing its effect on the cellular membrane (\_\_\_\_\_\_\_\_\_\_\_
50% dextrose and insulin
exchange resins such as Kayexelate if the patient’s bowels are working
IV calcium).
Causes of Metabolic Acidosis
• Excessive production of fixed acids (diabetic ketoacidosis, lactic acidosis, low-flow
states)
• Loss of buffers (loss of bicarbonate-rich fluids from the GI tract)
• Inability of the kidney to eliminate fixed acids (renal failure)
Metabolic alkalosis occurs from______ and _____
loss of acid gastric juice, or from excessive administration of bicarbonate (or precursors).
Mx of Met alk
In most cases, an abundant intake of KCl (5–10 mEq/h) will allow the kidney to correct the problem. Only rarely is ammonium chloride or 0.1 N HCl needed
Respiratory acidosis and alkalosis result from _____ and _________
impaired ventilation (acidosis) or abnormal hyperventilation (alkalosis).
