(1) Picking the wrong IV fluid type

To avoid picking the right IV fluid, we must understand the following:

1. The relation between Sodium and volume when giving IV fluid.
2. The free water content of each type of IV fluid.
3. Indications to start IV fluid.

The relation between sodium content and volume

The higher the sodium in the IV fluid, the more volume it will provide.

Free water content

The more hypotonic the solution is, the more free water content. Dextrose solutions are exceptions! 5% dextrose is an isotonic solution but contains 100% free water.

IV fluids indications

• Resuscitation.
• Maintenance.
• Free water replacement.
• Electrolyte repletion.

Resuscitation

• Replacement of the lost intravascular volume.
• The ideal IV fluid type for resuscitation:
  • Isotonic with sodium concentration similar or close to serum sodium concentration.
  • Doesn’t swell or shrink the cells.
  • Doesn’t significantly impact electrolyte levels.
• O.9 NS, LR, Plasmalyte, and isotonic bicarb drip are the ideal solutions for resuscitation.
• 0.9 NS and LR are the most commonly used, Plasmalyte is expensive and not widely available.
• LR is preferred in acute pancreatitis as it may reduce the risk of SIRS. Personally, I prefer LR over 0.9 NS in all indications.
• LR causes less hypernatremia, hypokalemia, and normal anion gap metabolic acidosis relative to 0.9 NS.
• Isotonic bicarb drip is ideal for volume resuscitation in:
  • Volume depletion + metabolic acidosis
  • Volume depletion + Hyperkalemia.
• For resuscitation, IV fluid has to be infused fast as a bolus or at a fast infusion rate (250-500 ml/hr).

Maintenance

• For prolonged NPO status (24 hours or more).
• The ideal IV fluid type for maintenance:
  • Contains free water.
  • contains glucose.
  • contains sodium and potassium.
• 0.45 NS + 5% dextrose + 20 meq KCL at 75-125 ml/hr is the ideal maintenance solution.
  • Remove dextrose if hyperglycemia develops.
  • Remove potassium if hyperkalemia develops.

Free water replacement

A water deficit of 2000 ml can be replaced with:

• 2000 ml of 5% dextrose solution.
• 2600 ml of 0.225 NS.
• 4000 ml of 0.45 NS.

Electrolytes replacement

• Potassium, magnesium, and phosphorus replacement.
• Premixed bags of KCL, MgCl, NaHco3, or KHco3.

(2) Not assessing the need for IV fluid daily

Assess the need to continue IV fluid daily and discontinue IV fluid as soon as the indication to start IV fluid isn’t valid anymore.

(3) Not monitoring signs of volume overload & electrolytes

• Check daily for signs of fluid overload (In fluids with high sodium load):
  • Peripheral edema.
  • Lung crackles (Sign of possible pulmonary edema).
  • shortness of breath (Sign of possible pulmonary edema).
  • Increased Oxygen requirements ( the patient was on room air and now on using some O2 or now is requiring higher amount of O2 compared to baseline).
• If any of the above signs, disocntinue IV fluid and initiate loop diuretics.
• Monitor HCo3 level to detect any Normal anion gap acidosis ( particularly with 0.9 NS). Discontinue IV fluid or switch to isotonic bicarb drip if resuscitation is still needed.
• Monitor potassium level.

(4) Considering CHF & ESRD automatic contraindications for IV fluid resuscitation

• IV fluid can be life-saving in Congestive heart failure and dialysis patients as they can become very dry and require an aggressive IV fluid resuscitation.
• Give IV fluid and periodically check for signs of volume overload (Mentioned earlier).
• Stop IV fluid if any sign or warning of IV fluid.

(5) Considering NPO an automatic indication IV fluid

• NPO isn’t an automatic indication for IV fluid, only a prolonged NPO status > 12-24 hours.
• If fluids indicated start a maintenance IV fluid.
• Discontinue as soon as NPO status is removed.