What is the rapid formula to calculate adjusted body weight in an obese adult patient?

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Fórmula Rápida para Calcular Peso Ajustado

La fórmula estándar más utilizada para calcular el peso ajustado (peso corporal ajustado) es: Peso Ajustado = Peso Ideal + 0.4 × (Peso Real - Peso Ideal). 1, 2

Fórmula Específica

Peso Ajustado (kg) = Peso Ideal (kg) + 0.4 × [Peso Corporal Total (kg) - Peso Ideal (kg)] 1, 2

Esta fórmula con factor de 0.4 es la más ampliamente recomendada por las guías de anestesiología y medicina crítica para pacientes obesos adultos. 1, 2

Cálculo del Peso Ideal (Necesario para la Fórmula)

Para aplicar la fórmula de peso ajustado, primero necesitas calcular el peso ideal:

  • Hombres: Peso Ideal (kg) = Altura (cm) ÷ 100 1
  • Mujeres: Peso Ideal (kg) = Altura (cm) ÷ 105 1

Fórmula alternativa (Devine): 3

  • Hombres: 51.65 kg + 1.85 kg por cada pulgada de altura sobre 5 pies 3
  • Mujeres: 48.67 kg + 1.65 kg por cada pulgada de altura sobre 5 pies 3

Variaciones del Factor de Ajuste Según Contexto Clínico

Es importante reconocer que diferentes contextos clínicos utilizan factores de ajuste ligeramente diferentes:

  • Factor 0.4: Recomendado para dosificación de anestésicos y la mayoría de medicamentos 1, 2
  • Factor 0.33: Utilizado por guías ESPEN para evaluación nutricional 2
  • Factor 0.25: Recomendado por K/DOQI para pacientes en diálisis 4
  • Factor 0.3-0.45: Utilizado para antibióticos hidrofílicos específicos (0.3 para beta-lactámicos, 0.4 para aminoglucósidos, 0.45 para quinolonas) 5

Cuándo Usar el Peso Ajustado

Debes usar el peso ajustado cuando: 4

  • El peso del paciente es <95% o >115% del peso ideal/estándar 4
  • El paciente tiene obesidad (BMI ≥30 kg/m²) y requiere dosificación de medicamentos 1
  • Se necesita calcular requerimientos nutricionales en pacientes con peso extremo 4

No es necesario usar peso ajustado cuando: 4

  • El peso del paciente está entre 95-115% del peso ideal 4
  • En este rango, puedes usar el peso corporal real directamente 4

Consideraciones Críticas

El peso ajustado reconoce que el tejido adiposo en exceso tiene menor actividad metabólica que el tejido magro, por lo que usar el peso corporal total resultaría en sobredosificación, mientras que usar solo el peso ideal subestimaría las necesidades. 4, 2

Para pacientes en hemodiálisis: Usa el peso post-diálisis para calcular el peso ajustado libre de edema. 4

Para pacientes en diálisis peritoneal: Usa el peso post-drenaje del dializado. 4

Advertencia importante: El uso de peso corporal total para dosificación de anestésicos en pacientes obesos aumenta significativamente el riesgo de sobredosis relativa, hipotensión y conciencia accidental bajo anestesia general. 1

References

1
Guideline

Weight Measurement and Calculation for Anesthesia

Praxis Medical Insights: Practical Summaries of Clinical Guidelines, 2026

2
Guideline

Adjusted Body Weight Calculation and Clinical Applications

Praxis Medical Insights: Practical Summaries of Clinical Guidelines, 2025

3
Research

Determination of ideal body weight for drug dosage calculations.

American journal of hospital pharmacy, 1983

4
Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

5
Research

Antimicrobial dosing in obese patients.

Clinical infectious diseases : an official publication of the Infectious Diseases Society of America, 1997

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Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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