Fluid/Blood Resuscitation

ANES 521:  Principles of Anesthesia Practice I

           In the operating room, patients suffer fluid and loss from a variety of mechanisms.  Most patients have been required to refrain from food or liquid intake for at least 8 hours prior to surgery.  During surgery, patients experience insensible or third space loss from viscera being exposed to evaporation.  Finally, many surgeries put the patient at risk for blood loss.  Intraoperative fluid and blood resuscitation is a required skill of every anesthesia provider.  This lesson will provide resources to review the current recommendations for fluid and blood replacement for patients undergoing surgery. 

         There are 2 types of fluids for volume resuscitation during surgery:

· Crystalloids

· Colloids

 

Crystalloids:

         Crystalloids are water-based solutions consisting of only water-soluble molecules such as mineral salts.  Because of decreased oncotic pressure of hypotonic and isotonic crystalloid solutions, they remain intravascularly for only about 20-30 minutes.  Hypertonic solutions are mainly used for hyponatremia and draw fluid into the vascular space.

 

Hypotonic crystalloid solutions include

· D5W

· 1/2 normal saline

 

Isotonic crystalloid solutions include

· Normal saline

· D5 0.2%NaCl

· Lactated ringers

· Plasmalyte

· 10% Dextran in 5% Dextrose

· 10% Dextran 40 in 0.9% NS

 

Colloids:

         Colloid solutions are liquids that contain insoluble molecules such as lipids, blood, proteins, etc.  Colloids stay within the intravascular space for much longer—3 to 6 hours. 

        

Fluid management during surgery

         To determine which type of fluid to give the patient, one must consider the type of fluid loss.  Primary water losses are replaced with hypotonic solutions (maintenance fluid).   Fluids used to  replace extracellular fluid are isotonic electrolyte solutions.

 

Maintenance fluids

· D5W

· D5 1/4 NS

Surgical fluid loss 

· NS

· LR

· Hetastarch

 

4:2:1 Rule  for maintenance fluids

         4 ml/kg for first 10 kg

         2 ml/kg for next 10 kg

         1 ml/kg for each kg above 20 kg

· Multiply the maintenance by the # hours NPO.  This is the NPO deficit.

· Give 1/2 the NPO the first hour + maintenance for that hour

· Give 1/4 NPO deficit + 1 hour of maintenance the second hour of surgery

· Give remaining 1/4 NPO deficit + 1 hour of maintenance the 3rd hour of surgery

 

Surgical fluid loss

· Minimal surgical trauma                2 ml/kg

         (hernia repair, D&C)   

· Moderate surgical trauma             4 ml/kg

         (cholecystectomy)

· Major surgical trauma                   6-8 ml/kg

         (bowel resection)

To replace blood loss, 3 to 4 ml of crystalloid is used to replace 1 ml of blood loss.

 

          

Fluid Replacement