Benefit of an enteral diet enriched with eicosapentaenoic acid and gamma-linolenic acid in ventilated patients with acute lung injury.
This review may be edited
Posted By: Elizabeth Sweetman
Posted Date: 26/03/09
Title: Benefit of an enteral diet enriched with eicosapentaenoic acid and gamma-linolenic acid in ventilated patients with acute lung injury.
Authors: Singer P, Theilla M, Fisher H, Gibstein L, Grozovski E, Cohen J.
Reference: Crit Care Med. 2006 Apr;34(4):1033-8
Link: Click here for a direct link to the paper. A password may be required for access to fulltext.
OBJECTIVE: To explore the effects of an enteral diet enriched with eicosapentaenoic acid (EPA), gamma-linolenic acid (GLA), and antioxidants on the respiratory profile and outcome of patients with acute lung injury.
DESIGN: Single-center, prospective, randomized, controlled, unblinded study.
SETTING: General intensive care department of a tertiary-care, university-affiliated hospital.
PATIENTS: A total of 100 patients with acute lung injury, diagnosed according to the American-European Consensus Conference on ARDS.
INTERVENTIONS: Patients were randomized to receive the standard isonitrogenous, isocaloric enteral diet or the standard diet supplemented with EPA and GLA for 14 days.
MEASUREMENTS AND MAIN RESULTS: Patient demographics, Acute Physiology and Chronic Health Evaluation II score, and type of admission were noted at admission. Compared with baseline oxygenation (EPA + GLA group vs. control group), by days 4 and 7, patients receiving the EPA + GLA diet showed significant improvement in oxygenation (PaO(2)/FIO(2), 317.3 +/- 99.5 vs. 214.3 +/- 56.4 and 296.5 +/- 165.3 vs. 236.3 +/- 79.8, respectively; p < .05). Compliance was significantly higher in the EPA + GLA group observed at day 7 (55.1 +/- 46.5 vs. 35.2 +/- 20.0 mL/mbar, p < .05). No significant difference was found in nutritional variables. Resting energy expenditure was significantly higher in patients in the EPA + GLA group, but their body mass index was also higher (p < .05). A significant difference was found in length of ventilation (p < .04) in favor of the EPA + GLA group. There was no between-group difference in survival.
CONCLUSIONS: In patients with acute lung injury, a diet enriched with EPA + GLA may be beneficial for gas exchange, respiratory dynamics, and requirements for mechanical ventilation.
Are the Results Valid?
1. Was the assignment of patients to treatments randomized? ( Was allocation concealment maintained?)
Patients were randomized to study groups, however, the randomization method used is unclear (p.1034).
2. Were all patients who entered the trial properly accounted for and attributed at its conclusion?
2a. Was followup complete?
5% (5/100) of enrolled patients were excluded from the final analysis.
Reasons for exclusion included; introduction of steriod therapy after randomization (n=2) and severe diarrhea (n=3).
The outcomes of patients excluded should have been made available in this paper and these patients should have been included in the final ITT analysis.
2b. Were patients analyzed in the groups to which they were randomized?
3. Were patients, health workers, and study personnel blind to treatment?
The authors state that this was not a blinded study (p.1036). Physicians, however, are stated as being blinded to the nutritional prescription (p.1034) and the investigator comparing outcome variables is stated as being the only one who knew the exact patient allocation (p.1036).
4. Were the groups similar at the start of the trial?
BMI and REE significantly higher in the EPA + GLA group compared to the control group:
  • BMI - (28.9+_6.2 vs 26.5+_5.4)
  • REE - (2132.4+_625.7 vs 1850.5+_334.2)
  • 5. Aside from the experimental intervention, were the groups treated equally?
    What are the Results?
    1. How large was the treatment effect?
    Primary Outcomes
    Oxygenation: Significantly higher in EPA + GLA group on Day 4 (Pa02/Fi02 317.3+_99.5 vs 214.3+_56.4, p<0.05) and on Day 7 (Pa02/Fi02 296.5+_165.3 vs 236.3+_79.8, p<0.05)(Table 3, p. 1035).
    Static Compliance: Improvement from Day 1 to Day 7 in EPA + GLA group (50.1+_37.5 to 55.1+_31.8 ml/mbar) compared to a decrease in the control group (44.1+_26.1 to 35.2+_20.0 ml/mbar)(P<0.05).
    Resistance: Decreased slightly in the EPA + GLA group from Day 1 to Day 7 (23.1+_18.3 to 20.14+_6.3 mbar-L sec)compared with the control group (22.5 +_17.2 to 30.9+_33.2 mbar-L sec) (<0.05).
    Secondary Outcomes
    Length of Ventilation (LOV): Significantly shorter LOV in the EPA + GLA group at day 7 (160.4+_15.2 vs 166.8+_5.2, P<0.03) (Table 4, p.1035, Mean & SD expressed as hours of ventilation).
    Mortality at Day 14: EPA + GLA Group (37% mortality) vs Control Group (35% mortality), P= Not significant.
    Note: Outcomes not statistically significant -Tidal volumes & Peep values, Length of ICU stay, Length of hospital stay and overall survival.
    2. How precise was the estimate of the treatment effect?
    There are no confidence intervals expressed within this paper, results expressed as mean and SD (p.1035-1037). See above for SDs.
    Will the Results Help Me In Caring For My Patients?
    1. Can the results be applied to my patient care?
    Yes these results could be considered for ALI/ARDS patients within our ICU.
    2. Were all clinically important outcomes considered?
    Explicit reporting of longer term mortality figures (>14 days) would be better.
    For completeness, the outcomes on the 5 excluded patients should have been reported.
    3. Are the likely treatment benefits worth the potential harms and costs?
    It would be of benefit to know more about the outcomes of the 3 excluded patients with severe diarrhoea in order to adequately balance the potential benefits with harms and costs.

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