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Modification of the Harris-Benedict equation to predict the energy requirements of critically ill patients during mild therapeutic hypothermia.

Abstract

The aim of the present study was the comparison of calculated and measured values of the energy expenditure of critically ill patients during the different phases of therapeutic mild hypothermia.

PATIENTS AND METHODS

Five patients (mean age 40.6 years, range 23 to 68 years, 2 females) suffering from severe acute cerebral injuries who underwent mild hypothermia were prospectively included into the study. Indirect calorimetry measurements were made at intervals of 3-4 hours and subsequently, during the steady state, at least every 12 hours. The results were compared with the basal metabolic rate calculated by the Harris-Benedict equation.

RESULTS

A close linear correlation between body temperature and basal metabolism could be observed across a wide range of temperatures from 30.5 degrees C to 38.3 degrees C (r=0.82, p<0.001). One degree drop in temperature led to a 5.9% reduction in energy. During mild hypothermia, oxygen consumption was reduced by 71 mL/min (95% confidence interval 57 to 86 mL/min; p<0.001) as compared to base line. The basal metabolism rate was decreased by 30.3% (95% confidence interval 24.7 to 35.9%, p<0.001). The average value recorded was 16.7% below the values calculated in accordance with the Harris-Benedict equation (95% confidence interval 12.8 to 20.6%).

CONCLUSION

The immediate reduction in oxygen requirements achieved by hypothermia is linearly correlated with the reduction in temperature and the hypothermia induced reduction in oxygen requirement recorded by indirect calorimetry is considerably below that calculated in accordance with the Harris-Benedict equation. If indirect calorimetry should not be available and the Harris-Benedict equation is used, a corrective factor is therefore needed to avoid an inaccurate calorie administration.

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  • Authors+Show Affiliations

    ,

    First Department of Medicine--Cardiology, Angiology, Pneumology, Intensive Care, University of Heidelberg, Mannheim, Germany.

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    MeSH

    Adult
    Aged
    Basal Metabolism
    Critical Illness
    Energy Intake
    Energy Metabolism
    Female
    Humans
    Hyperthermia, Induced
    Male
    Middle Aged
    Nutritional Requirements
    Oxygen Consumption
    Predictive Value of Tests
    Prospective Studies

    Pub Type(s)

    Journal Article

    Language

    eng

    PubMed ID

    18396797

    Citation

    Saur, Joachim, et al. "Modification of the Harris-Benedict Equation to Predict the Energy Requirements of Critically Ill Patients During Mild Therapeutic Hypothermia." In Vivo (Athens, Greece), vol. 22, no. 1, 2008, pp. 143-6.
    Saur J, Leweling H, Trinkmann F, et al. Modification of the Harris-Benedict equation to predict the energy requirements of critically ill patients during mild therapeutic hypothermia. In Vivo. 2008;22(1):143-6.
    Saur, J., Leweling, H., Trinkmann, F., Weissmann, J., Borggrefe, M., & Kaden, J. J. (2008). Modification of the Harris-Benedict equation to predict the energy requirements of critically ill patients during mild therapeutic hypothermia. In Vivo (Athens, Greece), 22(1), pp. 143-6.
    Saur J, et al. Modification of the Harris-Benedict Equation to Predict the Energy Requirements of Critically Ill Patients During Mild Therapeutic Hypothermia. In Vivo. 2008;22(1):143-6. PubMed PMID: 18396797.
    * Article titles in AMA citation format should be in sentence-case
    TY - JOUR T1 - Modification of the Harris-Benedict equation to predict the energy requirements of critically ill patients during mild therapeutic hypothermia. AU - Saur,Joachim, AU - Leweling,Hans, AU - Trinkmann,Frederik, AU - Weissmann,Joerg, AU - Borggrefe,Martin, AU - Kaden,Jens J, PY - 2008/4/10/pubmed PY - 2008/5/7/medline PY - 2008/4/10/entrez SP - 143 EP - 6 JF - In vivo (Athens, Greece) JO - In Vivo VL - 22 IS - 1 N2 - UNLABELLED: The aim of the present study was the comparison of calculated and measured values of the energy expenditure of critically ill patients during the different phases of therapeutic mild hypothermia. PATIENTS AND METHODS: Five patients (mean age 40.6 years, range 23 to 68 years, 2 females) suffering from severe acute cerebral injuries who underwent mild hypothermia were prospectively included into the study. Indirect calorimetry measurements were made at intervals of 3-4 hours and subsequently, during the steady state, at least every 12 hours. The results were compared with the basal metabolic rate calculated by the Harris-Benedict equation. RESULTS: A close linear correlation between body temperature and basal metabolism could be observed across a wide range of temperatures from 30.5 degrees C to 38.3 degrees C (r=0.82, p<0.001). One degree drop in temperature led to a 5.9% reduction in energy. During mild hypothermia, oxygen consumption was reduced by 71 mL/min (95% confidence interval 57 to 86 mL/min; p<0.001) as compared to base line. The basal metabolism rate was decreased by 30.3% (95% confidence interval 24.7 to 35.9%, p<0.001). The average value recorded was 16.7% below the values calculated in accordance with the Harris-Benedict equation (95% confidence interval 12.8 to 20.6%). CONCLUSION: The immediate reduction in oxygen requirements achieved by hypothermia is linearly correlated with the reduction in temperature and the hypothermia induced reduction in oxygen requirement recorded by indirect calorimetry is considerably below that calculated in accordance with the Harris-Benedict equation. If indirect calorimetry should not be available and the Harris-Benedict equation is used, a corrective factor is therefore needed to avoid an inaccurate calorie administration. SN - 0258-851X UR - https://www.unboundmedicine.com/medline/citation/18396797/Modification_of_the_Harris_Benedict_equation_to_predict_the_energy_requirements_of_critically_ill_patients_during_mild_therapeutic_hypothermia_ L2 - http://iv.iiarjournals.org/cgi/pmidlookup?view=long&amp;pmid=18396797 DB - PRIME DP - Unbound Medicine ER -