Postoperative Care Flashcards
Measurable fluid losses
EBL, fluid given intraoperatively, urine output
What fraction of fluid administered stays intravascularly? How much isotonic fluid must be given to replenish 1mL blood loss?
1/3 of fluid stays (2/3 moves to EC space)
3mL of isotonic fluid per 1mL of fluid loss
Insensible fluid losses
Evaporation during procedures especially in long procedures w/open peritoneal cavity. Difficult to quantify and must be estrimated based on urine output, vitals, and other physiologic measurements
Estimating maintenance fluid requirements by body weight
- 100mL/kg/24hr for first 10kg
- 50ml/kg/24hr for second 10kg
- 20ml/kg/24hr for anything above 20kg
Replenishing Na, K and Cl
- D5-0.5HS
2. KCl 20mEq/L
Replenishing fluid after large EBL
- Lactated ringer for first 24hrs
2. 0.9NS for first 24hrs
How do fluid requirements change with recovery
After GI function returns, 3rd space fluid volume will be excreted by the kidneys and thus fluid requirements will decrease during this phase. continued IV fluids may result in fluid overload, edema, and pulmonary edema
Normal urine output rate
0.5-1ml/kg/hr (e.g. 50mL/hr)
Causes of post-operative urine diuresis
- Preexisting renal disease with inabiltiy to concentrate urine
- Diabetes insipidus
- Combination of causes
- Post-obstructive diuresis (diuresis after clearance of an obstructino)
Causes of postobstructive diuresis
- Chronic obstruction
- Edema
- CHF
- HTN
- Wt gain
- Azotemia
Causes of diuresis
- Impaired concentration ability (pathologic)
- Impaired sodium resorption (pathologic)
- retained urea, sodium, and water (physiologic)
Implications of different urine osmolalities
- Urine w/low osmolaltiy = pathologic concentrating defect
2. Urine w/high osmolality = osmotic diuresis
Causes of oliguria
- mechanical obstruction (catheter etc.)
2. Severe dehydration (must volume resuscitate +/- CVP line or pulmonary artery catheter)
What does a pulmonary artery catheter tell you?
Indicator of preload and CO adequacy
Causes of hematuria
- Obstruction w/overdistention of bladder causing injury to bladder wall
- Malignancy
- INfection
- Kidney stones
- Trauma
- Prostatitis
- Med sfx causing hemorrhagic cystitis (Cyclophosphamide)