IV Fluids and Crystalloids
Types: crystalloid (e.g., NS or LR), free water (e.g., D5W), and colloid (e.g., albumin, blood products)
• Crystalloid can be isotonic (NS, LR), hypotonic (1/2 NS, 1/4 NS), or hypertonic (3% saline)
Bolus fluids = volume expansion in shock, sepsis (30 ml/kg), hemorrhage (initial resuscitation), GI losses, burns
• Normal saline in large volumes can cause hyperchloremic non-AG metabolic acidosis and ↑ need for RRT
• Rate: ~500cc-1L over 30 min-2 hr. If concerned about volume overload, start w/ smaller volume (250-500cc).
• LR or Plasma-lyte associated with better renal outcomes compared with NS
(SMART, NEJM 2018;378:829, SALT-ED, NEJM 2018;378:718).
• Colloid is not superior to crystalloid for volume resuscitation in sepsis (SAFE, NEJM 2004;350:2247)
Maintenance fluids = replace daily losses (~1.6L per day in adults w/ normal renal function and perspiration). Also used at higher rates in conditions such as pancreatitis and rhabdomyolysis.
• If patient is taking PO, there is no need for maintenance IV fluids
• D5-1/2 NS is typical maintenance fluid for NPO patients. Insufficient calories to replace a diet (~170 kcal/L).
• Maintenance rate: 60 ml/hr + 1 ml/kg/hr for every kg above 20 kg → ex. 60 kg adult = 100 ml/hr
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