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Recommendations Summary

CI: Monitoring Delivery of Energy in Critical Illness 2006

Click here to see the explanation of recommendation ratings (Strong, Fair, Weak, Consensus, Insufficient Evidence) and labels (Imperative or Conditional). To see more detail on the evidence from which the following recommendations were drawn, use the hyperlinks in the Supporting Evidence Section below.


  • Recommendation(s)

    CI: Monitoring delivery of energy

    Monitoring plan of critically ill patients must include a determination of daily actual EN intake. Enteral nutrition should be initiated within 48 hours of injury or admission and average intake actually delivered within the first week should be at least 60-70% of total estimated energy requirements as determined in the assessment. Provision of EN within this time frame and at this level may be associated with a decreased LOS, days on the mechanical ventilation and infectious complications.

    Rating: Fair
    Imperative

    • Risks/Harms of Implementing This Recommendation

      • Underfeeding in surgical ICU patients may lead to an increased LOS and medical costs (Neumayer et al, 2001)
      • Feeding medical ICU patients more than 70% of goal intake in the first five days of ICU stay is associated with a lower chance of being discharged alive or breathing spontaneously when discharged from the ICU (Dickerson et al,  2002; Krishnan et al,  2003)
      • Providing surgical patients with obesity more than 70% of goal intake over a seven-day period is associated with a longer LOS and more days of antibiotics (Dickerson et al,  2002)
      • A series of case studies have indicated that EN administered to patients with inadequate mesenteric perfusion may be associated with hypoxia and promote the development of small bowel hypoxia and necrosis (Rai et al, 1996; Lawlor et al, 1998; Melis et al, 2006).

       

    • Conditions of Application

      These recommendations are limited to critically ill patients in the early phase of ICU admission.

      Early EN is reportedly well tolerated by ICU patients. The following are guidelines for avoiding intestinal hypoxia and bowel necrosis (Rai et al, 1996; Lawlor et al, 1998; Melis et al, 2006):  

      • Feeding into the small bowel
      • Administering feedings in patients adequately resuscitated and when mean arterial pressure can be sustained at at least 70mm Hg
      • Use of iso-osmolar formulations
      • Advancement of feedings when tolerance demonstrated.

      Feedings should be held when a sudden period of hypotension occurs or if there is a need for increased dosages of pressor agents or an increased need for ventilatory support. Feedings should also be held with sudden increases in NG output, sudden abdominal distention or development of abdominal pain.  Further evaluation is indicated.

    • Potential Costs Associated with Application

      • In one neutral quality retrospective cost effectiveness study of surgical ICU patients, early (within 48 hours of surgery) and sufficient (>60% of feeding goals) nutrition support resulted in lower hospital charges, compared to those fed late or below 60% of the goal (Neumayer et al,  2001)
      • Early EN in ICU patients may require small bowel feeding tube placement, specifically in patients who are intolerant of gastric feedings or those who are at high risk for aspiration. Small bowel placement of feeding tubes requires the skill and time of a clinician at the bedside, endoscopic placement by a gastroenterologist or placement under fluoroscopy
      • The complications or undesireable outcomes (increased LOS, increased infectious complications,  more days of mechanical ventilation) associated with inappropriate (under- or over-feeding) EN feeding in ICU patients, affect the cost of hospitalization.

    • Recommendation Narrative

      Background

      • Actual attainment of full goal nutrient delivery by EN feedings in the first week of ICU admission is unusual
      • Most EN feedings were initiated within 48 hours of injury or ICU admission.

      Harms

      • One positive quality cohort (Krishnan et al, 2003) and one neutral quality cohort study (Dickerson et al, 2002) documented less positive outcomes when patients were fed caloric intake greater than 70% of goal (Krishnan et al, 2003)
        • In medical ICU patients who received the highest tertile of caloric intake, there was reduced likelihood of being discharged alive (0.82, CI 0.7-0.94) or breathing spontaneously at discharge from the ICU (0.69, CI 0.52-0.94)
          • These findings were strongest in patients with a Second Acute Physiology Score (SAPD II) above 50, a high acuity marker, where the tertile with over 66% of kcal goal intake had 0.47 odds (CI 0.28-0.75) of discharge alive (Krishnan et al, 2003).
        • In a neutral quality cohort study of patients with obesity, whose medical records were examined retrospectively, patients who actually received caloric intake from EN above 18kcal/kg adjusted body weight, had a shorter ICU LOS (18.6 vs. 28.5 days, P<0.03) and fewer antibiotic days (16.6 vs. 27.4, P<0.03) (Dickerson et al, 2002).
      • However, since both of these studies may be impacted by undocumented confounding clinical variables, such as inadequate glycemic control or "hidden" caloric supply (D5W, lipid-based sedatives), caution must be used in their interpretation.

      Mortality

      • One positive quality prospective double-blind trial (Atkinson et al, 1998), two neutral quality PRCTs (Kudsk et al, 1996; Taylor et al, 1999), one neutral quality prospective randomized double-blind multi-center trial (Bower et al, 1995) and one neutral quality retrospective cohort study (Dickerson et al, 2002) found no significant effect of the target feeding rate on mortality
      • One positive quality observational cohort study (Krishnan et al,  2003) of 187 patients placed into tertiles (Tertile I, 0%-32% of estimated needs; Tertile II, 33% to 65% of estimated needs; Tertile III, ≥66% of estimated needs), based on actual caloric intake (from EN, PN or a combination of EN and PN)
        • Compared to Tertile I, Tertile II was associated with a higher likelihood of being discharged alive (OR, 1.22, 95% CI 1.15-1.29).
      • Additional research is needed to determine the effect of energy delivery on mortality of medical care in critically ill patients.

      Infectious Complications 

      • A positive quality prospective cohort study (Krishnan et al, 2003) of 187 patients were placed into tertiles (Tertile I, 0% to 32% of estimated needs; Tertile II, 33% to 65% of estimated needs; Tertile III, ≥66% of estimated needs), based on actual caloric intake (from EN or PN) and found no difference in infection rate between the tertiles
      • Two neutral quality PRCTs (Kudsk et al, 1996; Taylor et al, 1999), one neutral quality prospective randomized double-blind multi-center trial (Bower et al, 1995) and one neutral quality retrospective cohort study (Dickerson et al, 2002) showed threshold intake of approximately 14-18kcal/kg per day or 60% to 70% of goal is associated with reduced infections.

      Length of Hospital Stay

      • One positive quality prospective randomized double-blind study (Atkinson et al, 1998) found patients who received more than 2.5 liters of an immune-enhancing EN formula, within 72 hours of ICU admission, had a shorter LOS
        • When analyzed based on intent-to-treat or a group who received any amount of immune-enhancing EN or standard EN, there was no significant difference in LOS.
      • Five neutral quality studies, including two PRCTs (Kudsk et al,  1996; Taylor et al,  1999), one neutral quality prospective randomized double-blind multi-center trial (Bower et al, 1995),  one retrospective cohort study (Dickerson et al,  2002) and one retrospective cost effectiveness study (Neumayer et al,  2001) demonstrated a shorter ICU or LOS with target rate of feeding at 60% to 70% of estimated calorie needs.

      Days on Mechanical Ventilation

      • One positive quality observational cohort study (Krishnan et al, 2003) found patients fed 33% to 66% of calorie needs to be more likely to be discharged from the ICU breathing spontaneously
      • Another positive quality prospective double-blind clinical trial study (Atkinson et al, 1998) found patients fed more than 2.5 liters of an immune-enhancing formula, within 72 hours of ICU admission, had fewer days of mechanical ventilation
      • Other neutral quality studies showed no significant difference in days on ventilator (Dickerson et al, 2002; Kudsk et al, 1996).

      Cost of Medical Care

      • One neutral quality retrospective cost effectiveness study (Neumayer et al, 2001) showed decreased charges associated with early and sufficient nutrition support
      • One neutral quality prospective study (Kudsk et al, 1996) found no difference in hospital charges between a standard EN group and an immune-enhancing EN group 
      • One neutral quality PRCT (Taylor et al, 1999) of patients with head injuries, who required mechanical ventilation and were randomized to receive standard EN and immune-enhancing EN, reported costs were not different between the two groups
        • The researchers extrapolated expected cost savings of more than 4 million pounds, based on the expected number of head injury patients requiring ICU care and mechanical ventilation.
      • Additional research is needed to determine the effect of energy delivery on cost of medical care in critically ill patients.

    • Recommendation Strength Rationale

      • Patient populations were not homogenous across all studies. Patient populations included patients with obesity; non-obese, trauma, surgical and medical patients and ICU patients with burns. 
      • Two studies (Neumayer et al, 2001; Krishnan et al,  2003) included patients on EN, PN or a combination of EN and PN. The other studies included only patients on EN (Kudsk et al,  1996; Taylor et al,  1999; Dickerson et al,  2002).
      • Confounding clinical variables, such as inadequate glycemic control or other sources of calories (IV dextrose or lipid-based sedatives) were not documented in all studies and can impact outcomes
      • Conclusion statements are Grade II and III.