Consequences of malnutrition 
              Consequences of malnutrition 
     Underfeeding                                      Overfeeding
      Underfeeding                                     Overfeeding
     Loss of muscle mass                      Increased VO
      Loss of muscle mass                      Increased VO
                                                                 2
                                                                 2
     Reduced respiratory function Increased VCO
      Reduced respiratory function Increased VCO
                                                                   2
                                                                   2
     Reduced immune function                           Hyperglycaemia
      Reduced immune function                          Hyperglycaemia
     Poor wound healing                                Fatty infiltration 
      Poor wound healing                               Fatty infiltration 
        of liver
         of liver
     Gut mucosal atrophy 
      Gut mucosal atrophy 
     Reduced protein synthesis
      Reduced protein synthesis
                                                                             2
                                                                             2
                    Calorie requirement 
                    Calorie requirement 
     Various formulae exist to calculate the patient’s 
        Various formulae exist to calculate the patient’s 
        basal  metabolic  rate  but  they  are  often 
        basal  metabolic  rate  but  they  are  often 
        misleading in critical illness.
        misleading in critical illness.
     Metabolic rate can be measured at the bedside by 
        Metabolic rate can be measured at the bedside by 
        indirect calorimetry but most patients will require 
        indirect calorimetry but most patients will require 
        2000-2700  Cal/day  or  less  if  starved  or 
        2000-2700  Cal/day  or  less  if  starved  or 
        underweight.
        underweight.
                                                                    3
                                                                    3
                  Nitrogen requirements 
                  Nitrogen requirements 
     Nitrogen  excretion  can  be  calculated  in  the 
        Nitrogen  excretion  can  be  calculated  in  the 
                                                             th
                                                             th
        absence of renal failure according to the 24  urea 
        absence of renal failure according to the 24  urea 
        excretion. 
        excretion. 
              Nitrogen (g/24h) = 2 + Urinary urea 
              Nitrogen (g/24h) = 2 + Urinary urea 
                         (mmol/24h) x 0.028
                         (mmol/24h) x 0.028
     However,  as  with  most  formulae,  this  method 
        However,  as  with  most  formulae,  this  method 
        lacks accuracy. 
        lacks accuracy. 
     Most patients require 7-14g/day.
        Most patients require 7-14g/day.
                                                                    4
                                                                    4
                     Other requirements
                      Other requirements
     The normal requirements of substrates, vitamins and 
        The normal requirements of substrates, vitamins and 
       trace elements are tabled opposite.
        trace elements are tabled opposite.
     Most critically ill patients require folic acid and vitamin 
        Most critically ill patients require folic acid and vitamin 
       supplementation  during  nutritional  support,  e.g. 
        supplementation  during  nutritional  support,  e.g. 
       Solvitio.
        Solvitio.
     Trace  elements  are  usually  supplemented  in 
        Trace    elements  are  usually  supplemented  in 
       parenteral formulae but should not be required during 
        parenteral formulae but should not be required during 
       enteral nutrition. 
        enteral nutrition. 
                                                                     5
                                                                     5
        Normal daily requirements (for a 70kg adult)
        Normal daily requirements (for a 70kg adult)
     Water              2100ml                     Trace elements
     Water              2100ml                     Trace elements
     Energy             2000-2700Cal               Iron               1-2mg
     Energy             2000-2700Cal               Iron               1-2mg
     Nitrogen           7-14g                      Copper             0.5-1.0mg
     Nitrogen           7-14g                      Copper             0.5-1.0mg
     Glucose            210g                       Managanese         1-2ug
     Glucose            210g                       Managanese         1-2ug
     Lipid              140g                       Zinc               2-4mg
     Lipid              140g                       Zinc               2-4mg
     Sodium             70-140 mmol                Iodide             70-140 ug
     Sodium             70-140 mmol                Iodide             70-140 ug
     Potassium                   50-120 mmol                Flurodie           1-2mg
     Potassium                   50-120 mmol                 Flurodie          1-2mg
     Calcium            5-10 mmol
     Calcium            5-10 mmol
     Magnesium          5-10 mmol
     Magnesium          5-10 mmol
     Phosphate          10-20 mmol
     Phosphate          10-20 mmol
              Vitamins
               Vitamins
     Thiamine                    16-19mg
     Thiamine                    16-19mg
     Riboflavin                  3-8mg
     Riboflavin                  3-8mg
     Niacin             33-34mg
     Niacin             33-34mg
     Pyridoxine         5-10mg
     Pyridoxine         5-10mg
     Folate             0.3-0.5mg
     Folate             0.3-0.5mg
     Vitamin C                   250-450mg
     Vitamin C                   250-450mg
     Vitamin A                   2800-3300iu
     Vitamin A                   2800-3300iu
     Vitamin D                   280-330iu
     Vitamin D                   280-330iu
     Vitamin E                   1.4-1.7iu
     Vitamin E                   1.4-1.7iu
     Vitamin K                   0.7mg
     Vitamin K                   0.7mg
                                                                                      6
                                                                                      6