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Difficulty: HardTrauma and Burns

A 34-year-old female is brought to the emergency department via helicopter after being rescued from a residential house fire. The burn injury occurred at 14:00, and she arrives at the trauma bay at 17:00. Her weight is 90 kg90 \text{ kg}. Physical examination reveals deep partial-thickness and full-thickness burns involving her entire anterior trunk (chest and abdomen), her entire right arm (circumferential), and the anterior surface of her left leg. The remainder of her skin is uninjured. En route to the hospital, paramedics successfully intubated her for airway protection and administered 740 mL740 \text{ mL} of lactated Ringer solution intravenously. According to current Advanced Trauma Life Support (ATLS) guidelines (2 mL/kg/%TBSA2 \text{ mL/kg/\%TBSA} for adult thermal burns), what should be the intravenous fluid infusion rate in mL/hr\text{mL/hr} for the remainder of the first 8-hour post-injury period?

Answer: 500 mL/hr

Answer

500
The correct infusion rate is 500 mL/hr500 \text{ mL/hr}. First, estimate the total body surface area (TBSA) burned using the Rule of Nines: the entire anterior trunk accounts for 18%18\%, the entire right arm is 9%9\%, and the anterior surface of the left leg is 9%9\%. Total TBSA = 18%+9%+9%=36%18\% + 9\% + 9\% = 36\%. Next, apply the ATLS fluid resuscitation guideline for adult thermal burns (2 mL/kg/%TBSA2 \text{ mL/kg/\%TBSA}) to determine the total 24-hour requirement: 2 mL×90 kg×36=6480 mL2 \text{ mL} \times 90 \text{ kg} \times 36 = 6480 \text{ mL}. Half of this total volume, which is 3240 mL3240 \text{ mL}, is required during the first 8 hours post-injury. Because the patient already received 740 mL740 \text{ mL} in transit, the remaining volume needed to complete the first 8-hour requirement is 3240 mL−740 mL=2500 mL3240 \text{ mL} - 740 \text{ mL} = 2500 \text{ mL}. Finally, because the patient arrived at the hospital 3 hours after the burn occurred (14:00 to 17:00), there are exactly 5 hours remaining in the initial 8-hour window. The appropriate infusion rate is calculated as 2500 mL/5 hours2500 \text{ mL} / 5 \text{ hours}, which equals 500 mL/hr500 \text{ mL/hr}.

Step-by-Step Solution

1
Calculate the Total Body Surface Area (TBSA) burned using the Rule of Nines.
Anterior trunk (18%18\%) + entire right arm (9%9\%) + anterior left leg (9%9\%) = 36%36\% TBSA.
Accurate TBSA is required as a primary variable for burn fluid resuscitation formulas.
2
Calculate the total 24-hour fluid requirement using the modern ATLS guideline for thermal burns.
2 mL×90 kg×36%=6480 mL2 \text{ mL} \times 90 \text{ kg} \times 36\% = 6480 \text{ mL}.
This determines the baseline total volume of lactated Ringer solution needed for the first day.
3
Determine the target fluid volume for the first 8 hours post-injury.
6480 mL/2=3240 mL6480 \text{ mL} / 2 = 3240 \text{ mL}.
Standard burn resuscitation protocols dictate that half of the total 24-hour volume must be administered in the first 8 hours from the time of the burn.
4
Adjust for fluids already administered in the prehospital setting.
3240 mL−740 mL=2500 mL3240 \text{ mL} - 740 \text{ mL} = 2500 \text{ mL}.
Accounts for the volume given during transport to prevent dangerous over-resuscitation and compartment syndrome.
5
Calculate the infusion rate for the remaining time in the 8-hour window.
2500 mL/5 hours=500 mL/hr2500 \text{ mL} / 5 \text{ hours} = 500 \text{ mL/hr}.
Because 3 hours elapsed between the injury (14:00) and arrival (17:00), only 5 hours remain in the initial 8-hour post-injury window.

Key Concept

Burn fluid resuscitation calculations require TBSA estimation using the Rule of Nines, application of the ATLS volume guidelines, adjustments for time elapsed since the burn, and deduction of prehospital fluids administered.
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Topics

Trauma and Burns

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