2: Postoperative Care Flashcards
How should blood loss be replaced with IVF? NG tube drainage? Excess urine?
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.
What is the “rule of thumb” for insensible operative fluid loss for large open abdominal procedures? Smaller open procedures? Minor procedures?
Large open abdominal: 5-10 mL/kg/hr
Smaller open: 3-5 ml/L/kg/hr
Minor: 1-2 mL/kg/hr
How are maintenance fluid requirements estimated by weight?
What is the maintenance fluid requirement for 65 kg person?
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
What can cause fluid overload a few days after surgery in a vulnerable patient?
Mobilization of fluid that third-spaced during surgery
What is normal urine output, by weight?
0.5-1 ml/kg/hr.
What does the osmolarity indicate in a post-op patient with excessive urine output?
Low osmolarity: concentration defect
Normal osmolarity: osmotic diuresis
What are the most common problems of low urine output in the postoperative period?
- Catheter obstruction
2. Dehydration
What are the first steps in assessing a postoperative patient who develops oliguria?
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.
What is a normal CVP?
1-8 cm H20 = 1-6 mm Hg
What is suggested by cloudy urine and disorientation in a postoperative patient?
Urosepsis
What measurements should be taken to determine whether oliguria is prerenal or postrenal?
- Urine osmolarity
- Urine Na+
- FeNa (%)
- BUN / Cr ratio
What is urine osmolarity in prerenal oliguria? Postrenal?
Prerenal: >500 mOsm/kg
Postrenal: 250-300 mOsm/kg
What is urine Na+ in prerenal oliguria? Postrenal?
FeNa?
Prerenal: urine Na+ <20 mEq/L, FeNA <1%
Postrenal: urine Na+ >40 mEq/L, FeNa >3%
What is BUN/Cr ratio in prerenal oliguria? Postrenal?
Prerenal: >20 (BUN reabsorption)
Postrenal: <10
How long does it take for catheter-based urosepsis to develop?
Can be within as little as hours
What is the most likely cause of hematuria after a foley is place to relieve obstructive urinary retention?
What are other causes?
Most likely: bladder wall injury after overdistension
Others: trauma, UTI, prostatitis, stones, malignancy, medications e.g. cyclophosphamide
What should be done if urine output drops in a catheterized patient with hematuria?
Irrigate to dislodge any clots.
Recurrent clotting may require constant irrigation with a three-way Foley.
What are warning signs of severe infection in a patient with a UTI?
Nausea, vomiting, abdominal or flank pain
What should be done if a surgical wound exhibits fluctuance on exam?
Examine and open wound, drain pus, assess fascial integrity, initiate local wound care.
What factors influence management when a peripheral IV catheter is surrounded by inflammation?
What is management in each case?
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.
How should suppurative/septic phlebitis at an IV site be treated?
IV removal.
Excision of vein up to normal segment
IV antibiotics
Leave wound open
What is the most common cause of immediate post-operative fever?
What else could it be?
Atelectasis is most common (usually low fever, unless major collapse)
Wound infection can also cause (can be a high fever)
What does gram-positive, spore-producing rods isolated from a wound mean?
What is management?
Clostridium wound infection.
Requires debridement and high-dose Penicillin G. Hyperbaric oxygen may help.
What tests should initially be ordered if a post-operative patient has new dyspnea?
CXR, ABGs, EKG
