What is the recommended fluid management plan for a patient with 45% Total Body Surface Area (TBSA) burns?

Fluid Management for 45% TBSA Burns

For a patient with 45% TBSA burns, immediately administer 20 mL/kg of Ringer's Lactate within the first hour, then calculate 24-hour fluid requirements using the Parkland Formula (2-4 mL/kg/% TBSA), giving half in the first 8 hours and half over the next 16 hours, while titrating to urine output of 0.5-1 mL/kg/hour. 1

Immediate Initial Resuscitation (First Hour)

• Give 20 mL/kg of balanced crystalloid (Ringer's Lactate or Hartmann's solution) intravenously within the first hour, regardless of precise burn size calculation 1, 2
• Do not delay this initial bolus while calculating exact TBSA—this addresses early hypovolemic shock 1
• Establish IV access immediately, preferably in unburned areas 3, 2

Calculating 24-Hour Fluid Requirements

For adults with 45% TBSA burns, use the Parkland Formula:

• Calculate: 2-4 mL/kg/% TBSA for 24 hours 1
• For a 70 kg patient with 45% TBSA: 6,300-12,600 mL total over 24 hours
• Start at 4 mL/kg/% TBSA (12,600 mL for 70 kg patient) given the large burn size 1

Timing of administration:

• Give half of the calculated volume in the first 8 hours post-burn 1, 3
• Give the remaining half over the next 16 hours 1, 3
• Time starts from the moment of injury, not from arrival 3

Primary Monitoring Parameter

Urine output is your primary endpoint for titrating fluid rates:

• Target: 0.5-1 mL/kg/hour in adults 1, 3
• This is the easiest and fastest parameter to monitor 1
• Adjust fluid rates up or down based on urine output, not rigid formula adherence 1

Critical Considerations for Large Burns (45% TBSA)

Expect higher fluid requirements than the formula predicts:

• Studies show patients with burns >40% TBSA often require volumes exceeding the Parkland formula 4, 5
• Full-thickness burns (which are likely present with 45% TBSA) increase fluid requirements and should use the higher end of the range (4 mL/kg/% TBSA) 1, 2
• Weight inversely correlates with fluid requirements per kg—lighter patients need proportionally more 5

Assess for inhalation injury immediately:

• Inhalation injury significantly increases mortality and fluid requirements 1, 2
• Look for circumoral burns, oropharyngeal burns, carbonaceous sputum, and history of enclosed space fire 6
• If mechanical ventilation is required, expect substantially higher fluid needs 5

Avoiding "Fluid Creep" (Over-Resuscitation)

This is a major pitfall—76% of resuscitations exceed the upper Parkland limit, averaging 6.3 mL/kg/% TBSA: 1, 2

• Over-resuscitation causes compartment syndrome, pulmonary edema, intestinal edema, acute kidney injury, pneumonia, bloodstream infections, ARDS, multiorgan failure, and increased mortality 1, 7
• Once adequate urine output (0.5-1 mL/kg/hour) is achieved, do not continue excessive fluid rates 1
• Patients receiving larger volumes than predicted have higher risk of complications (OR 1.92 for pneumonia, OR 2.33 for bloodstream infections, OR 1.74 for death) 7

Colloid Supplementation

• Consider albumin 5% supplementation starting at 8-12 hours post-burn if fluid rates exceed expected targets 1
• Target serum albumin >30 g/L 1
• Never use hydroxyethyl starches (HES)—they are contraindicated 1

Accurate TBSA Assessment

Use the Lund-Browder chart, not the Rule of Nines:

• The Rule of Nines overestimates TBSA in 70-94% of cases, leading to dangerous fluid over-administration 1
• Reassess TBSA during initial management to prevent both overtriage and undertriage 1

Special Monitoring Considerations

• Monitor for circumferential burns causing compartment syndrome—may require escharotomy within 48 hours 3, 2
• If electrical burn mechanism, maintain higher urine output (1-2 mL/kg/hour) to prevent myoglobin-induced renal injury and monitor for deeper tissue damage 3
• Advanced monitoring (transpulmonary thermodilution, lactate levels) may detect early hypovolemia not reflected by blood pressure and urine output alone, though standard monitoring suffices for most cases 4

Common Pitfalls to Avoid

• Do not rigidly adhere to formulas—titrate to urine output 1
• Do not use the Rule of Nines for TBSA calculation 1
• Do not continue excessive fluid rates once adequate urine output is achieved 1
• Do not delay initial 20 mL/kg bolus while calculating precise TBSA 1
• Do not ignore signs of inhalation injury or electrical injury, which dramatically increase fluid needs 1, 3