Enteral omega-3 fatty acid, gamma-linolenic acid, and antioxidant supplementation in acute lung injury

Emerging therapies for treatment of acute lung injury and acute respiratory distress syndrome

In 2007, Bosma et. al provided a comprehensive review of emerging therapies for the acute respiratory distress syndrome (ARDS), a condition which continues to carry a mortality rate of greater than 30%. Over the past several years, the development of novel and effective therapeutic agents for ARDS remains disappointing, and unfortunately, no recent therapeutic interventions have demonstrated a clear benefit. Herein, the results of several of these early and late phase clinical trials are reviewed, the majority of which address known maladaptive processes that have been deemed critical in ARDS pathophysiology. Based on the ongoing futility of current therapeutic models to yield effective therapies, it is speculated whether or not novel treatment paradigms, which address distinctly different aspects of this disease paradigm, may be warranted.

Antioxidants and micronutrient supplementation in trauma patients

PURPOSE OF REVIEW

This study reviews important nutrients responsible for oxidant-antioxidant balance in trauma patients requiring admission to the ICU and rationale for repletion of antioxidants using pharmaconutrition.

RECENT FINDINGS

Oxidative stress is an underlying cause of critical illness due to oxidant-antioxidant imbalance. Multiple nutrients important to oxidative balance have been studied, yet much variety exists among the dosing, timing, and route of administration. Conflict also exists regarding the benefits of particular single nutrients and the effects of combination therapy. Anticipated results of the Reducing Deaths due to Oxidative Stress trial hope to provide further insight to the use of antioxidants in critically ill patients.

SUMMARY

The goal of this review, though not exhaustive, serves to highlight recent significant studies regarding antioxidant use in the ICU setting while calling for sufficiently powered randomized, controlled trials to elucidate appropriate guidelines for antioxidant administration in regards to ideal dosing, route of administration, timing of administration, duration of therapy, and the role of single versus combination supplementation.

Initial trophic vs full enteral feeding in patients with acute lung injury: the EDEN randomized trial

CONTEXT

The amount of enteral nutrition patients with acute lung injury need is unknown.

OBJECTIVE

To determine if initial lower-volume trophic enteral feeding would increase ventilator-free days and decrease gastrointestinal intolerances compared with initial full enteral feeding.

DESIGN, SETTING, AND PARTICIPANTS

The EDEN study, a randomized, open-label, multicenter trial conducted from January 2, 2008, through April 12, 2011. Participants were 1000 adults within 48 hours of developing acute lung injury requiring mechanical ventilation whose physicians intended to start enteral nutrition at 44 hospitals in the National Heart, Lung, and Blood Institute ARDS Clinical Trials Network.

INTERVENTIONS

Participants were randomized to receive either trophic or full enteral feeding for the first 6 days. After day 6, the care of all patients who were still receiving mechanical ventilation was managed according to the full feeding protocol.

MAIN OUTCOME MEASURES

Ventilator-free days to study day 28.

RESULTS

Baseline characteristics were similar between the trophic-feeding (n = 508) and full-feeding (n = 492) groups. The full-feeding group received more enteral calories for the first 6 days, about 1300 kcal/d compared with 400 kcal/d (P < .001). Initial trophic feeding did not increase the number of ventilator-free days (14.9 [95% CI, 13.9 to 15.8] vs 15.0 [95% CI, 14.1 to 15.9]; difference, -0.1 [95% CI, -1.4 to 1.2]; P = .89) or reduce 60-day mortality (23.2% [95% CI, 19.6% to 26.9%] vs 22.2% [95% CI, 18.5% to 25.8%]; difference, 1.0% [95% CI, -4.1% to 6.3%]; P = .77) compared with full feeding. There were no differences in infectious complications between the groups. Despite receiving more prokinetic agents, the full-feeding group experienced more vomiting (2.2% vs 1.7% of patient feeding days; P = .05), elevated gastric residual volumes (4.9% vs 2.2% of feeding days; P < .001), and constipation (3.1% vs 2.1% of feeding days; P = .003). Mean plasma glucose values and average hourly insulin administration were both higher in the full-feeding group over the first 6 days.

CONCLUSION

In patients with acute lung injury, compared with full enteral feeding, a strategy of initial trophic enteral feeding for up to 6 days did not improve ventilator-free days, 60-day mortality, or infectious complications but was associated with less gastrointestinal intolerance.

TRIAL REGISTRATION

clinicaltrials.gov Identifiers: NCT00609180 and NCT00883948.

The expression of HSPs, anti-oxidants, and cytokines in plasma and bronchoalveolar lavage fluid of patients with acute respiratory distress syndrome

Objectives

We studied several acute inflammatory materials (AIM) such as various inflammatory cytokines, oxidative stress, and heat shock proteins in ARDS patients by simultaneously measuring from bronchoalveolar lavage fluid (BALF) and plasma.

Design and methods

AIM were measured by using plasma and BALF sampling obtained from ARDS group (n = 12) and non-ARDS group (n = 12).

Results

In the BALF, only HSP 47 was significantly increased in ARDS group than non-ARDS group. In plasma, GRP 94, HSP 90, HSP 60, HSP 47, GPx-3, and IL-8 were increased significantly in ARDS group. In short, most of the AIM in BALF or plasma were not significantly different in ARDS group as compared with non-ARDS group. Ninety-day mortality was significantly related to HSP90, HSP 60 and GPx-3 in plasma but not in BALF.

Conclusion

Alteration of AIM levels in both BALF or plasma of ARDS group was not remarkable compared with the non-ARDS group. Our result suggests the need to reconsider ARDS pathophysiology and therapeutic strategy.

The effect of raw soybean on oxidative status of digestive organs in mice

The present study was undertaken to specify the effect of raw soybean on oxidative status of digestive organs in mice. For this purpose, thirty male (C57BL/6J) mice were randomly divided into three groups and fed on different diets as follows: Group 1 was fed on control diet, Group 2 was fed on raw soybean diet and Group 3 was fed on raw soybean diet supplemented with 30 mg/kg cysteamine. After two weeks of feeding, duodenum, liver and pancreas samples were collected to measure oxidative and antioxidative parameters. The results show that ingestion of raw soybean markedly increased contents of superoxide anion and malondialdehyde (MDA) and activity of inducible nitric oxide synthase (iNOS), decreased activity of superoxide dismutase (SOD), T-AOC and content of reduced glutathione (GSH) in digestive organs of mice (P < 0.05). In the group fed with raw soybean diet supplemented with cysteamine, oxidative stress was mitigated. However, oxidative parameter levels were still higher than those of control diet-fed group. The present study indicates that ingestion of raw soybean could result in an imbalance between oxidant and antioxidant, and thus induce oxidative stress in digestive organs of mice.