2: Postoperative Care

Question 1

How should blood loss be replaced with IVF? NG tube drainage? Excess urine?

Answer 1

Blood loss should be replaced with a 3:1 ratio, because 2/3 of IVF rapidly leaves the blood.

NG tube drainage and excess urine output should be replaced at 1:1 ratio.

Question 2

What is the “rule of thumb” for insensible operative fluid loss for large open abdominal procedures? Smaller open procedures? Minor procedures?

Answer 2

Large open abdominal: 5-10 mL/kg/hr
Smaller open: 3-5 ml/L/kg/hr
Minor: 1-2 mL/kg/hr

Question 3

How are maintenance fluid requirements estimated by weight?

What is the maintenance fluid requirement for 65 kg person?

Answer 3

For 24 hours:
First 10 kg: 100 ml/kg (1 L per 10 kg)
Second 10 kg: 50 ml/kg (0.5 L per 10 kg)
Additional weight: 20 ml/kg (0.2 L for 10 kg)

For 65 kg: 1 + 0.5 + 4.5*0.2 = 2.4 L

Question 4

What can cause fluid overload a few days after surgery in a vulnerable patient?

Answer 4

Mobilization of fluid that third-spaced during surgery

Question 5

What is normal urine output, by weight?

Answer 5

0.5-1 ml/kg/hr.

Question 6

What does the osmolarity indicate in a post-op patient with excessive urine output?

Answer 6

Low osmolarity: concentration defect

Normal osmolarity: osmotic diuresis

Question 7

What are the most common problems of low urine output in the postoperative period?

Answer 7

1. Catheter obstruction

2. Dehydration

Question 8

What are the first steps in assessing a postoperative patient who develops oliguria?

Answer 8

First check for catheter obstruction, if there is one (bladder ultrasound or irrigating catheter).

Then see if they respond to IVF.

If not, consider assessing with central venous pressure measurement.

Question 9

What is a normal CVP?

Answer 9

1-8 cm H20 = 1-6 mm Hg

Question 10

What is suggested by cloudy urine and disorientation in a postoperative patient?

Answer 10

Urosepsis

Question 11

What measurements should be taken to determine whether oliguria is prerenal or postrenal?

Answer 11

1. Urine osmolarity
2. Urine Na+
3. FeNa (%)
4. BUN / Cr ratio

Question 12

What is urine osmolarity in prerenal oliguria? Postrenal?

Answer 12

Prerenal: >500 mOsm/kg
Postrenal: 250-300 mOsm/kg

Question 13

What is urine Na+ in prerenal oliguria? Postrenal?

FeNa?

Answer 13

Prerenal: urine Na+ <20 mEq/L, FeNA <1%
Postrenal: urine Na+ >40 mEq/L, FeNa >3%

Question 14

What is BUN/Cr ratio in prerenal oliguria? Postrenal?

Answer 14

Prerenal: >20 (BUN reabsorption)
Postrenal: <10

Question 15

How long does it take for catheter-based urosepsis to develop?

Answer 15

Can be within as little as hours

Question 16

What is the most likely cause of hematuria after a foley is place to relieve obstructive urinary retention?
What are other causes?

Answer 16

Most likely: bladder wall injury after overdistension

Others: trauma, UTI, prostatitis, stones, malignancy, medications e.g. cyclophosphamide

Question 17

What should be done if urine output drops in a catheterized patient with hematuria?

Answer 17

Irrigate to dislodge any clots.

Recurrent clotting may require constant irrigation with a three-way Foley.

Question 18

What are warning signs of severe infection in a patient with a UTI?

Answer 18

Nausea, vomiting, abdominal or flank pain

Question 19

What should be done if a surgical wound exhibits fluctuance on exam?

Answer 19

Examine and open wound, drain pus, assess fascial integrity, initiate local wound care.

Question 20

What factors influence management when a peripheral IV catheter is surrounded by inflammation?
What is management in each case?

Answer 20

Uncomplicated (induration, edema, tenderness only): Remove IV
Significant cellulitis: Remove IV, antibiotics
Septic phlebitis (purulent drainage, bacteremia persisting after catheter removal): IV removal, vein excision, IV antibiotics, leave wound open.

Question 21

How should suppurative/septic phlebitis at an IV site be treated?

Answer 21

IV removal.
Excision of vein up to normal segment
IV antibiotics
Leave wound open

Question 22

What is the most common cause of immediate post-operative fever?
What else could it be?

Answer 22

Atelectasis is most common (usually low fever, unless major collapse)

Wound infection can also cause (can be a high fever)

Question 23

What does gram-positive, spore-producing rods isolated from a wound mean?
What is management?

Answer 23

Clostridium wound infection.

Requires debridement and high-dose Penicillin G. Hyperbaric oxygen may help.

Question 24

What tests should initially be ordered if a post-operative patient has new dyspnea?

Answer 24

CXR, ABGs, EKG

Question 25

What are some key causes of hemoptosis in the post operative period?

Answer 25

Key: pulmonary infarct from PE or infection (pneumonia, bronchitis, TB)
Others: Malignancy

Question 26

What are two potential causes of acute hypotension and desaturation in a postoperative patient?

Answer 26

MI and massive PE

Question 27

How should small bowel enterocutaneous fistula be managed under different conditions?

Answer 27

Peritoneal signs: surgical re-exploration
Otherwise: CT to check for fluid collection, which is drained if found.
Then make NPO, give TPN, measure fistula output.

Question 28

What causes can lead to failure of a enterocutaneous fistula to heal with supportive care?

Answer 28

FRIENDS:
Foreign body in the wound
Radiation damage
Infection/inflammatory bowel disease
Epithelialization of the fistulous tract
Neoplasm
Distal bowel obstruction
Steroids

Question 29

How long should it take for an enterocutaneous fistula to heal with non-surgical management?
What should be done if this does not occur?

Answer 29

Should heal within a few weeks.
If it does not begin to close appropriate, investigate with small bowel series and/or fistulogram.
If does not close, definitively close surgically.