Podrobný sprievodca čoskoro
Pracujeme na komplexnom vzdelávacom sprievodcovi pre Parkland Formula (Burns). Čoskoro sa vráťte pre podrobné vysvetlenia, vzorce, príklady z praxe a odborné tipy.
The Parkland Formula (also known as the Baxter Formula or colloquially the 'push-pull rule' for fluid resuscitation in burns) is the most widely used guideline for calculating intravenous fluid requirements in the first 24 hours following a significant burn injury. Originally described by Charles Baxter at Parkland Memorial Hospital in Dallas in the 1960s and later formalised, it calculates the total volume of isotonic crystalloid (0.9% normal saline or Lactated Ringer's solution, though LR is preferred to avoid hyperchloraemic acidosis) based on two patient-specific variables: body weight in kilograms and the percentage of total body surface area (%TBSA) affected by second and third degree burns. The formula gives: Total fluid in 24 hours = 4 mL × weight (kg) × %TBSA burned. Critically, only partial thickness (second degree) and full thickness (third degree) burns are included in the TBSA calculation — superficial (first degree) burns are excluded as they do not cause the same fluid shift. The first half of the calculated volume is administered over the first 8 hours, timed from the moment of injury (not from hospital arrival), and the remaining half over the subsequent 16 hours. Adequacy of resuscitation is monitored by urine output, targeting 0.5–1 mL/kg/hour in adults (1 mL/kg/hour in children). Over-resuscitation (fluid creep) is a recognised modern complication and can lead to abdominal compartment syndrome, pulmonary oedema, and worsening of local tissue oedema. The Parkland Formula provides a starting volume that must be titrated to physiological response rather than rigidly administered.
Total 24h fluid (mL) = 4 × Weight (kg) × %TBSA burned; First half over 8h from time of burn; Second half over next 16h
- 1Step 1 — Determine %TBSA: Use Rule of Nines (adults) or Lund-Browder chart (children) to calculate percentage of body surface area with second or third degree burns only. Exclude first degree burns.
- 2Step 2 — Measure patient weight: Use actual body weight in kilograms. In obese patients, use ideal body weight or adjusted body weight to prevent over-resuscitation.
- 3Step 3 — Calculate total 24-hour volume: Total = 4 mL × weight (kg) × %TBSA. Use Lactated Ringer's solution as the preferred fluid (normal saline increases risk of hyperchloraemic acidosis).
- 4Step 4 — Divide the volume: Half of total volume to be given in the first 8 hours, timed from the moment of injury, not from hospital admission.
- 5Step 5 — Calculate first 8-hour rate: Remaining time until 8 hours post-burn must be determined. If patient arrives 2 hours post-burn, the first half must be given over 6 hours, requiring adjustment of the infusion rate.
- 6Step 6 — Second half over 16 hours: The remaining half of total volume is given evenly over the next 16 hours (hours 8–24 from burn time).
- 7Step 7 — Titrate to urine output: Insert urinary catheter and target urine output of 0.5–1 mL/kg/hour in adults. Adjust infusion rate up or down to achieve this target. Avoid rigid adherence to calculated rate.
Rate first 8h = 525 mL/h; Rate next 16h = 262.5 mL/h. Target UO 35–70 mL/h
4 × 70 × 30 = 8,400 mL total. Half = 4,200 mL in 8 hours = 525 mL/h. Second half 4,200 mL over 16h = 262.5 mL/h.
High rate required due to 2h delay — monitor for fluid overload; target UO 40–80 mL/h
Total = 12,800 mL. First half 6,400 mL must be given in 6 hours (not 8) as 2h already elapsed. Rate = 6,400/6 = 1,067 mL/h.
Children also require maintenance dextrose-containing fluid in addition to Parkland volume; target UO 1 mL/kg/h
Parkland = 2,000 mL in 24h. Children must receive glucose-containing maintenance fluids separately to prevent hypoglycaemia.
Adipose tissue does not increase fluid requirements proportionally; use IBW to prevent massive over-resuscitation
Using actual 120 kg would give 16,800 mL — dangerously high. ABW = IBW + 0.4×(AW–IBW) = 75 + 0.4×45 = 93 kg is an alternative. Titrate closely to UO.
Emergency department immediate burns resuscitation planning for patients with major thermal injuries, representing an important application area for the Push Pull Rule in professional and analytical contexts where accurate push pull rule calculations directly support informed decision-making, strategic planning, and performance optimization
Pre-hospital calculation by HEMS crews to begin fluid resuscitation en route to burn centre, representing an important application area for the Push Pull Rule in professional and analytical contexts where accurate push pull rule calculations directly support informed decision-making, strategic planning, and performance optimization
Burn centre ICU management of large area burns requiring extended resuscitation over 24–48 hours, representing an important application area for the Push Pull Rule in professional and analytical contexts where accurate push pull rule calculations directly support informed decision-making, strategic planning, and performance optimization
Paediatric burns units requiring formula adaptation with maintenance fluids for children, representing an important application area for the Push Pull Rule in professional and analytical contexts where accurate push pull rule calculations directly support informed decision-making, strategic planning, and performance optimization
Military combat casualty care for flame and blast injury with large TBSA involvement, representing an important application area for the Push Pull Rule in professional and analytical contexts where accurate push pull rule calculations directly support informed decision-making, strategic planning, and performance optimization
Inhalation Injury
{'title': 'Inhalation Injury', 'body': 'Inhalation injury increases systemic capillary leak and fluid requirements independently of cutaneous burn size. Patients with confirmed or suspected inhalation injury (singed nasal hairs, carbonaceous sputum, hoarse voice, stridor) often require 30–50% more fluid than Parkland formula predicts. Early intubation is indicated before airway oedema causes obstruction.'}
Paediatric Burns
{'title': 'Paediatric Burns', 'body': 'Children have higher body surface area to weight ratios, higher baseline fluid requirements, and are at greater risk of hypothermia and hypoglycaemia. In addition to Parkland volume, maintenance dextrose-containing fluid must be given. Lund-Browder chart is essential for TBSA calculation as Rule of Nines is inaccurate for children.'}
Elderly Patients
In the Push Pull Rule, this scenario requires additional caution when interpreting push pull rule results. The standard formula may not fully account for all factors present in this edge case, and supplementary analysis or expert consultation may be warranted. Professional best practice involves documenting assumptions, running sensitivity analyses, and cross-referencing results with alternative methods when push pull rule calculations fall into non-standard territory.
Certain complex push pull rule scenarios may require additional parameters beyond the standard Push Pull Rule inputs.
These might include environmental factors, time-dependent variables, regulatory constraints, or domain-specific push pull rule adjustments materially affecting the result. When working on specialized push pull rule applications, consult industry guidelines or domain experts to determine whether supplementary inputs are needed. The standard calculator provides an excellent starting point, but specialized use cases may require extended modeling approaches.
| Parameter | Value |
|---|---|
| Formula | 4 mL × weight (kg) × %TBSA |
| Fluid type | Lactated Ringer's (preferred) / 0.9% NaCl |
| First half | Over first 8 hours from time of burn |
| Second half | Over next 16 hours (hours 8–24) |
| UO target (adult) | 0.5–1.0 mL/kg/hour |
| UO target (child) | 1.0 mL/kg/hour |
| Burns included in TBSA | 2nd and 3rd degree only |
| Burns excluded | Superficial (1st degree) burns |
Why is the timing from injury (not arrival) so important?
The first 8-hour window is defined from the time of burn, not from hospital arrival. If a patient arrives 3 hours post-burn, the first half of the Parkland volume must be infused in the remaining 5 hours, requiring a higher infusion rate. Failure to adjust for time elapsed causes inadequate resuscitation in the critical early phase.
Why is Lactated Ringer's preferred over normal saline?
Normal saline is hyperchloraemic (154 mEq/L chloride vs plasma 100 mEq/L), and large volumes cause hyperchloraemic metabolic acidosis, which worsens coagulopathy and organ function. Lactated Ringer's (or Hartmann's solution) is near-isotonic with a more physiological electrolyte composition and is recommended by ABA guidelines as the preferred resuscitation fluid. This is particularly important in the context of push pull rule calculations, where accuracy directly impacts decision-making. Professionals across multiple industries rely on precise push pull rule computations to validate assumptions, optimize processes, and ensure compliance with applicable standards. Understanding the underlying methodology helps users interpret results correctly and identify when additional analysis may be warranted.
What is fluid creep and why is it dangerous?
Fluid creep refers to the administration of fluid volumes substantially exceeding Parkland formula predictions, resulting in resuscitation volumes that are 2–3 times the formula recommendation in contemporary clinical practice. Consequences include abdominal compartment syndrome (raised intra-abdominal pressure compressing viscera), pulmonary oedema, conversion of partial thickness burns to full thickness, and extremity compartment syndrome.
Should colloid be added to burns resuscitation?
Colloid (human albumin solution, 5%) is occasionally added after 8 hours when large-volume crystalloid has been given, to help restore oncotic pressure. The Brooke formula uses half Parkland crystalloid volumes plus colloid. Evidence is mixed; most UK and US burn centres use Parkland crystalloid alone in the first 24 hours and reassess colloid need thereafter.
What urine output target should be used in burns resuscitation?
Target UO 0.5–1.0 mL/kg/hour in adults (approximately 30–50 mL/h for a 70 kg adult). In children target 1.0 mL/kg/hour. UO is the primary titration parameter. High UO (>1 mL/kg/h) suggests over-resuscitation (reduce rate by 10–20%); low UO (<0.5 mL/kg/h) suggests under-resuscitation (increase rate by 10–20%). This is particularly important in the context of push pull rule calculations, where accuracy directly impacts decision-making. Professionals across multiple industries rely on precise push pull rule computations to validate assumptions, optimize processes, and ensure compliance with applicable standards. Understanding the underlying methodology helps users interpret results correctly and identify when additional analysis may be warranted.
Are electrical or chemical burns managed differently?
Yes — electrical burns cause deep tissue destruction not visible on skin surface, so %TBSA underestimates injury severity. Myoglobinuria from muscle necrosis requires higher fluid rates (1 mL/kg/h UO target to clear myoglobin) to prevent acute tubular necrosis. Chemical burns require copious early irrigation and assessment of systemic toxin absorption.
What happens in the second 24 hours of burns resuscitation?
After 24 hours, capillary integrity partially restores. Fluid requirements decrease significantly. Colloid (5% albumin) is often started to maintain oncotic pressure, and crystalloid rates are reduced. The second 24 hours aims to begin gentle diuresis of the oedema accumulated in the first 24 hours. This is particularly important in the context of push pull rule calculations, where accuracy directly impacts decision-making. Professionals across multiple industries rely on precise push pull rule computations to validate assumptions, optimize processes, and ensure compliance with applicable standards. Understanding the underlying methodology helps users interpret results correctly and identify when additional analysis may be warranted.
When is the Parkland Formula not appropriate?
Burns under 15% TBSA in adults can often be managed with oral hydration. Inhalation injury significantly increases fluid requirements beyond Parkland predictions. Patients with cardiac failure or renal failure require modified protocols with invasive haemodynamic monitoring. Always use Parkland as a guide, not a rigid prescription. This is particularly important in the context of push pull rule calculations, where accuracy directly impacts decision-making. Professionals across multiple industries rely on precise push pull rule computations to validate assumptions, optimize processes, and ensure compliance with applicable standards. Understanding the underlying methodology helps users interpret results correctly and identify when additional analysis may be warranted.
Pro Tip
Calculate the Parkland rate at the bedside: first 8-hour rate (mL/h) = (2 × weight × %TBSA) / hours remaining until 8h post-burn. For a 70 kg patient with 30% TBSA presenting at time of burn: rate = (2 × 70 × 30) / 8 = 525 mL/h. Immediately insert a urinary catheter and adjust rates hourly based on urine output.
Did you know?
Charles Baxter developed the Parkland Formula in the 1960s at Parkland Memorial Hospital — the same Dallas hospital where President John F. Kennedy was pronounced dead in 1963. The formula emerged from systematic research correlating fluid requirements with burn size, replacing earlier protocols that included colloid in the first 24 hours, which Baxter showed was unnecessary and potentially harmful.
References
- ›Baxter CR — Fluid Volume and Electrolyte Changes in the Early Post-Burn Period (Clin Plast Surg 1974)
- ›American Burn Association — Burn Care Practice Guidelines 2023
- ›Pruitt BA Jr — Fluid Resuscitation for Extensive Burns (Ann Emerg Med 1990)
- ›ISBI Practice Guidelines for Burn Care 2016
- ›LITFL Parkland Formula Burns Resuscitation