Pre-Op and Post-Op Care

Question 1

Older patient with history of multiple MIs scheduled for elective sigmoid resection for diverticular disease. Preoperative radionuclide ventriculography shows EF of less than 0.35. Next steps?

Answer 1

Prohibitive cardiac risk to surgery (high incidence of perioperative MI), so continue with medical therapy of diverticular disease. If an abscess develops, percutaneous drainage is only option.

Question 2

Goldman’s predictors of operative cardiac risk?

Answer 2

JVD, recent MI (within 6 months), PVCs (>5/min), non-sinus rhythm, age over 70, emergency surgery, valvular stenosis, poor medical condition, or surgery within the chest or abdomen

Question 3

Worst single finding predicting high operative cardiac risk, and optimal management?

Answer 3

JVD (indicating CHF), managed with calcium-channel blockers, beta blockers, digitalis, and diuretics

Question 4

Alternative management of acute cholecystitis in patient with high cardiac risk?

Answer 4

Percutaneous radiologic tube cholecystostomy

Question 5

Most common cause of increased operative pulmonary risk, and optimal management?

Answer 5

Smoking (compromised ventilation with high PCO2 and low FEV1, not necessarily compromised oxygenation), managed with cessation for 8 weeks and intensive respiratory therapy (physical therapy, expectorants, incentive spirometry, humidified air)

Question 6

Indicators of operative hepatic risk?

Answer 6

Bilirubin > 2, Albumin < 3, PT > 22, blood ammonia concentration > 150 ng/dL, and encephalopathy

Question 7

Indicators of operative nutritional risk?

Answer 7

20% body weight loss over 2 months, serum albumin < 3, anergy to injected skin-test antigens, and serum transferrin level < 200 mg/dL

Question 8

Management of perioperatie nutrition risk?

Answer 8

At least 4-5 days (7-10 optimal) of perioperative nutritional support, preferably via the gut

Question 9

Biggest surgical risk in diabetic patients?

Answer 9

Diabetic ketoacidosis is an absolute contraindication to any surgery

Question 10

Patient develops rapid rise in body temp (>104) shortly after onset of general anesthetic with inhaled halothane and muscle relaxation with succinylcholine. Metabolic acidosis and hypercalcemia are also noted. +/- family history of death under anesthesia. Diagnosis and management?

Answer 10

Malignant hyperthermia, treat with IV dantrolene plus 100% oxygen, correction of acidosis, cooling blankets, and monitoring for myoglobinuria.

Question 11

Less than an hour after cystoscopy, patient develops chills and fever spikes to 104 F. Diagnosis and management?

Answer 11

This early on after an invasive procedure and this high a fever means bacteremia. Blood cultures x 3 and start empiric antibiotics.

Question 12

Patient develops fever of 102 F on POD #1 s/p abdominal procedure. Most likely diagnosis and management?

Answer 12

Most likely atelectasis, but get CXR, look at wound and IV sites, inquire about UTI symptoms, and improve ventilation (deep breathing and coughing, postural drainage, incentive spirometry). Recalcitrant atelectasis gets bronchoscopy.

Question 13

Causes of post-op fever, in rough sequential order of occurrence?

Answer 13

Atelectasis (POD 1), pneumonia (POD 3), UTI (POD 3), deep thrombophlebitis (POD 5), wound infection (POD 7), PE (POD 7), deep abscess (POD 10-15)…potential mnemonic = 4 Ws (Wind - atelectasis, Water - UTI, Walking - deep thrombophlebitis, Wound - infection)…also consider drug reactions.

Question 14

Patient with persistent fever starting POD 10, suspicious for deep abscess. Next step?

Answer 14

CT scans for pelvic or subphrenic abscesses until they can be found and drained percutaneously

Question 15

When is perioperative MI most likely? What is the biggest triggering cause? Most diagnostic test?

Answer 15

Within the first 3 post-op days, biggest cause is hypovolemic shock, troponins are most reliable.

Question 16

Common findings in post-op PE?

Answer 16

Sudden development of severe pleuritic chest pain about 7 days post-op, with shortness of breath, anxiety, diaphoresis, tachycardia, and prominent vein distention (low venous pressure excludes PE)

Question 17

Workup and management of potential post-op PE?

Answer 17

Start with arterial blood gases (need to see hypoxemia and hypocapnia), usually followed by V/Q scan (though this only works well in otherwise normal lungs) or CT scan. Angiography is gold standard but invasive. Management starts with heparinization (not clot-busters) and Greenfield filter in vena cava if recurrent PEs are observed during anticoagulation.

Question 18

Prevention and management of aspiration?

Answer 18

Prevention: empty stomach, antacids before induction
Management: first, lavage and removal of particulate matter (aided by bronchoscopy); then bronchodilators and respiratory support

Question 19

Pt with TB undergoing abdominal surgery, halfway through becomes progressively more difficult to bag. and BP steadily declines while CVP rises. No evidence of intraabdominal bleeding. Diagnosis and management?

Answer 19

Intraoperative tension pneumothorax (blown pulmonary bleb), managed by surgeon making a hole in the diaphragm (formal chest tube later)

Question 20

Most lethal cause of post-operative disorientation? Test to order first?

Answer 20

Hypoxia; order a blood gas

Question 21

7 metabolic causes of post-op delirium?

Answer 21

uremia, hyponatremia, hypernatremia, ammonium, hyperglycemia, delirium tremens, iatrogenic drug reaction

Question 22

Second week of complicated post-op, pt becomes progressively disoriented and unresponsive. Bilateral pulmonary infiltrates, pO2 65 on 40% oxygen, no evidence of congestive heart failure. Diagnosis and management?

Answer 22

Mental changes due to hypoxia, findings consistent with adult respiratory distress syndrome (ARDS). Underlying cause could be pre-existing lung disease, trauma, or sepsis. Mainstay of therapy is PEEP with permissive hypercapnia to minimize barotrauma.

Question 23

Alcoholic pt undergoing elective colon resection for recurrent diverticular bleed, claiming he has been sober for 6 months. POD 3 he becomes disoriented and combative and claims to see elephants climbing the walls. Diagnosis and management?

Answer 23

Delirium tremens, managed acutely with IV alcohol (5% alcohol/5% dextrose) and chronically with psychopharmacology

Question 24

42-year-old pt who becomes confused and lethargic 12 hrs post-hysterectomy, complaining of severe headache. She has a grand mal seizure and goes into coma. Chart review shows D5W mistakenly infused at 525/hr instead of 125/hr. Diagnosis and management?

Answer 24

Water intoxication (hyponatremia), probably managed with very careful use of hypertonic saline.

Question 25

Young pt becomes lethargic, confused, and comatose 8 hrs post-hypophysectomy for prolactinoma. Urinary output has been 600/hr since surgery, IVF replacement 100/hr. Diagnosis and management?

Answer 25

Surgically induced diabetes insipidus (hypernatremia), managed with either D5W (acutely) or one-third or one-fourth normal saline.

Question 26

Cirrhotic pt goes into a coma after an emergency portocaval shunt for bleeding esophageal varices. Diagnosis?

Answer 26

Hyperammonemia, possibly accompanied by hypokalemic alkalosis, high cardiac output, and low peripheral resistance in the setting of ouvert liver failure.

Question 27

Most common post-op urinary problem? Management options?

Answer 27

Inability to void, more common in men. Management is in-and-out catheterization, or an indwelling Foley if catheterization has to be repeated.

Question 28

Pt with indwelling Foley after abdominal surgery, stable vital signs but zero urine output in last 2 hours. Diagnosis?

Answer 28

No evidence of decreased renal perfusion, so probably a mechanical problem (plugged or kinked catheter most likely)

Question 29

Pt post-trauma surgery with consecutive hourly urine outputs of 12, 17, and 9. Systolic BP between 95-130. Next steps?

Answer 29

Either he is behind on fluid replacement or has gone into renal failure. Fluid challenge will produce diuresis in a dehydrated patient but not in renal failure, but urinary sodium can also tell the story (40 mEq/L in renal failure) or look at the FENa (>1 indicates renal failure)

Question 30

Pt POD #4 s/p ex-lap has abdominal distention without pain. No bowel sounds or flatus and abdominal x-rays show dilated loops of small bowel without air-fluid levels. Diagnosis and management?

Answer 30

Probably paralytic ileus, managed with continued NPO and NG suction until peristaltic activity resumes. Prolonged symptoms need to have obstruction ruled out with a barium tag. Also rule out hypokalemia.

Question 31

Elderly pt with Alzheimer'swith abdominal distention POD #5 s/p femoral neck repair. No tenderness, ocasional bowel sounds, x-rays show very distended colon and a few distended loops of small bowel. Diagnosis and management?

Answer 31

Ogilvie syndrome (massive colonic dilatation), commonly seen in elderly or non-active pts. Colonoscopy indicated to suck out gas, rule out mechanical obstruction, and allow a rectal tube to be left in place afterward.

Question 32

Presentation, risk factors, and treatment of wound dehiscence?

Answer 32

Large amounts of salmon-colored fluid soaking the wound dressings. Risk factors inclue age, diabetes, obesity, poor stitching, trauma to wound site, and connective tissue disorders like Ehlers-Danlos. Treatment is taping securely, binding the abdomen, and minimizing mobilization and coughing.

Question 33

Management of evisceration?

Answer 33

Cover with large moist dressings soaked in warm saline and rush to OR for closure

Question 34

Pt POD #7 s/p open inguinal hernia repair found to have a red, hot, tender, boggy incision site. Pt reports a fever for last two days. Diagnosis and management?

Answer 34

Wound infection (likely to see pus as well), managed by opening and draining the wound. If findings are equivocal, antibiotics may be preventive and sonogram is diagnostic.

Question 35

Feculent drainage from a wound on POD #9, pt afebrile and doing well. Diagnosis and management? What if pt were febrile?

Answer 35

Fecal fistula, inconvenient but not serious, will close with little or no therapy. Febrile, sick pts have feces on the inside and need drainage and probably diverting colostomy.

Question 36

Pt POD #8 s/p hemigrastectomy and gastroduodenostomy beginning to leak 2-3 L of green fluid per day through his abdominal wound. Diagnosis and management?

Answer 36

If acute abdomen, surgical exploration...if not febrile or sick, leakage of gastroduodenal contents does not indicate further surgery right away. Massive fluid and electrolyte replacement with TEN delivered to upper jejunum is best, TPN second, hopefully healing occurs without another operation.

Question 37

How to calculate free water deficit in hypernatremia?

Answer 37

Every 3 mEq/L Na above 140 = 1 L free water lost

Question 38

62-year-old pt undergoing chemotherapy for metastatic breast cancer found to have asymptomatic hyponatremia. Next steps?

Answer 38

Probably due to SIADH, slow enough that the brain has been able to adapt. Rapid correction would be lethal, manage with water restriction instead.

Question 39

68-year-old pt with incarcerated umbilical hernia, abdominal distention, dehydration, and persistent fecaloid vomiting for 5 days. Serum sodium is 118. Next steps?

Answer 39

Loss of isotonic fluid from the gut means she is volume-depleted and hyponatremic. Needs fluid replacement but tonicity must be corrected slowly. Use lots of isotonic fluids (NSS or LR depending on acid-base status).

Question 40

Danger of correcting diabetic ketoacidosis with vigorous insulin and IV fluids?

Answer 40

Profound hypokalemia as potassium rushes back into cells due to insulin and acid-base correction.

Question 41

18-year-old pt with crushed R leg, hypotensive and in hypovolemic shock, receiving several units of blood, now acidotic. What electrolyte abnormality is most concerning and how does it develop? Treatment?

Answer 41

Hyperkalemia from crushed muscle, blood transfusions, acidosis, and poor renal clearance due to hypoperfusion. Management is insulin (+ 50% dextrose), exchange resins, and IV calcium, with hemodialysis in severe cases.

Question 42

Elderly alcoholic, diabetic pt with poor renal function sustains multiple trauma and goes in and out of shock during resuscitation and surgery. Blood gases show pH 7.1, pCO2 36, and serum electrolytes are Na 138, Cl 98, and HCO3 15. Mechanism of acidosis and management?

Answer 42

Lactic acid production due to shock, with diabetes, alcohol, and renal insufficiency all contributing. He has an anion gap metabolic acidosis with incomplete respiratory compensation by Winter's formula, managed with lots of LR (NSS could give too much chloride)

Question 43

Pt s/p subtotal gastrectomy for cancer with a Billroth 2 reconstruction (gastrojejunostomy) develops blowout of the duodenal stump and duodenal fistula. For 10 days, pt has drained 1 L/day of green fluid, and serum electrolytes are Na 132, Cl 104, HCO3 15, pH 7.2, pCO2 35. What kind of acidosis, how did it develop, and therapy?

Answer 43

Metabolic acidosis without anion gap, developed through loss of bicarbonate in the fistula, therapy is IV fluid replacement with lots of bicarbonate (or lactate or acetate).

Question 44

How does loss of acid gastric juice (i.e. prolonged vomiting) affect serum electrolytes? How is it corrected?

Answer 44

Hypochloremic, hypokalemic metabolic alkalosis, corrected via rehydration with saline and potassium chloride (and rarely ammonium chloride)