What is the initial fluid bolus dosage for treating shock?

Initial Fluid Bolus for Treating Shock

The recommended initial fluid bolus for treating shock is 20-30 mL/kg of isotonic crystalloid solution, administered rapidly within the first hour of resuscitation. 1, 2

Type of Fluid

• Isotonic crystalloid solutions (such as lactated Ringer's solution or normal saline) are the preferred initial fluid for resuscitation in shock 1
• Balanced/buffered crystalloids (like lactated Ringer's) are slightly preferred over 0.9% saline due to lower risk of hyperchloremic metabolic acidosis 1, 2
• Colloids (albumin, starches, gelatin) offer no survival advantage over crystalloids in the initial resuscitation phase and are more expensive 1
• Starches should be avoided due to increased risk of renal dysfunction and mortality 1, 3

Initial Bolus Volume and Rate

• For adults with septic shock: 30 mL/kg crystalloid within the first 3 hours, with most given in the first hour 2, 1
• For children with septic shock: 20 mL/kg crystalloid bolus (10-20 mL/kg per individual bolus) 1
• For hypovolemic shock in children: 20 mL/kg isotonic crystalloid bolus even if blood pressure is normal 1
• Fluid should be administered rapidly - typically over 5-15 minutes per bolus 2, 4
• Recent evidence suggests that completing the initial 30 mL/kg fluid resuscitation within 1-2 hours is associated with the lowest mortality rate 5

Administration Technique

• Use a fluid challenge technique where fluid administration is continued as long as hemodynamic parameters continue to improve 2
• Boluses of 250-1000 mL (in adults) or 10-20 mL/kg (in children) can be administered rapidly and repeatedly as part of this technique 1
• In resource-limited settings without ICU availability, more conservative fluid administration is recommended 1

Assessment of Response

• After each fluid bolus, reassess for signs of clinical improvement and fluid overload 1
• Clinical markers to evaluate response include: 1, 2
  • Heart rate
  • Blood pressure
  • Capillary refill time
  • Level of consciousness
  • Urine output
  • Skin temperature and perfusion
• Serum lactate can be used to assess response, with a goal of 20% reduction in the first hour 1
• Continue fluid boluses if signs of shock persist and there are no signs of fluid overload 1

Signs to Stop Fluid Resuscitation

• Development of signs of fluid overload: 1
  • Pulmonary edema (crackles/rales on auscultation)
  • Worsening respiratory status
  • New or worsening hepatomegaly
  • Increased work of breathing
  • Hypoxemia
• No improvement in tissue perfusion despite adequate volume administration 1
• Achievement of hemodynamic goals (normalized blood pressure, heart rate, capillary refill) 2

Special Considerations

• In patients with traumatic brain injury or burns, higher volumes of fluid may be required 1
• In malnourished patients or those with pre-existing cardiac dysfunction, more cautious fluid administration may be necessary 1
• In resource-limited settings without ICU access, if hypotension is present, administer up to 40 mL/kg in boluses (10-20 mL/kg per bolus) over the first hour 1

Common Pitfalls

• Delayed resuscitation increases mortality - immediate fluid resuscitation is essential 2
• Relying solely on blood pressure to guide resuscitation may be inadequate; assess multiple clinical parameters 1, 2
• Failure to reassess after each bolus can lead to fluid overload 1
• Excessive fluid administration beyond what is needed for shock reversal may worsen outcomes 6, 3
• Using colloids as first-line therapy increases costs without improving outcomes and may increase risk of renal injury 1, 3