A Randomized Trial of Enteral Glutamine for Treatment of Burn Injuries.

BACKGROUND: Glutamine is thought to have beneficial effects on the metabolic and stress response to severe injury. Clinical trials involving patients with burns and other critically ill patients have shown conflicting results regarding the benefits and risks of glutamine supplementation. METHODS: In a double-blind, randomized, placebo-controlled trial, we assigned patients with deep second- or third-degree burns (affecting ≥10% to ≥20% of total body-surface area, depending on age) within 72 hours after hospital admission to receive 0.5 g per kilogram of body weight per day of enterally delivered glutamine or placebo. Trial agents were given every 4 hours through a feeding tube or three or four times a day by mouth until 7 days after the last skin grafting procedure, discharge from the acute care unit, or 3 months after admission, whichever came first. The primary outcome was the time to discharge alive from the hospital, with data censored at 90 days. We calculated subdistribution hazard ratios for discharge alive, which took into account death as a competing risk. RESULTS: A total of 1209 patients with severe burns (mean burn size, 33% of total body-surface area) underwent randomization, and 1200 were included in the analysis (596 patients in the glutamine group and 604 in the placebo group). The median time to discharge alive from the hospital was 40 days (interquartile range, 24 to 87) in the glutamine group and 38 days (interquartile range, 22 to 75) in the placebo group (subdistribution hazard ratio for discharge alive, 0.91; 95% confidence interval [CI], 0.80 to 1.04; P = 0.17). Mortality at 6 months was 17.2% in the glutamine group and 16.2% in the placebo group (hazard ratio for death, 1.06; 95% CI, 0.80 to 1.41). No substantial between-group differences in serious adverse events were observed. CONCLUSIONS: In patients with severe burns, supplemental glutamine did not reduce the time to discharge alive from the hospital. (Funded by the U.S. Department of Defense and the Canadian Institutes of Health Research; RE-ENERGIZE ClinicalTrials.gov number, NCT00985205.).

Autonomic specificity in emotion: The induction method matters.

Research on the autonomic specificity of emotion has spanned decades, yet the findings of this research are still highly debated. Although many studies have explored the autonomic specificity of emotions, few have concurrently explored the influence by which the induction methods themselves have had in directing autonomic change. The current study was conducted to assess whether the methods for emotion elicitation could be meaningfully captured by multivariate pattern classification techniques that have been previously used to explore autonomic specificity of emotion. This aim was achieved by using three separate emotion-elicitation methods to elicit five separate emotions. A sample of 64 college-aged students watched film clips, read imagery scripts, and recalled personal memories for five emotion states. Using multivariate pattern classification analysis, the evidence from the current study lends further support for autonomic specificity of emotion, but also highlights the role that the specific induction technique contributes to autonomic changes that accompany emotions in the laboratory.

Individual differences in behavioral activation and cardiac vagal control influence affective startle modification.

The startle response (SR) has a close relationship with stress responses. Startle modification (SRM) has been widely used to study stress disorders (e.g., posttraumatic stress disorder). The framework of the behavioral inhibition and activation systems (BIS/BAS) has been thought to correspond with withdrawal and approach motivational processes underlying affective SRM and can influence stress reactivity. Vagally-mediated cardiac activity as indexed by heart rate variability (HRV) has been associated with SRM and regulatory processes during stress. In the present study, the influence of individual differences in the BIS/BAS and resting HRV on affective SRM were examined. Eighty-six subjects viewed affective pictures while acoustic SR stimuli were delivered. Individual differences in motivation were measured by the BIS/BAS scales. The magnitude of SR was assessed as electromyographic activity of the SR eyeblink during pictures of different valences. Resting HRV was derived from electrocardiography. In contrast to previous studies, the present results showed that startle inhibition and potentiation were related to BAS and HRV, but not to BIS. There was also an interaction of BAS and HRV, indicating that the relationship between HRV and SRM strengthened as BAS scores decreased. The present findings suggest that BAS may relate to both withdrawal and approach, and trait stress reactivity is influenced by BAS and cardiac vagal activity. In addition, BAS moderates the relationship between cardiac vagal activity and SRM. These findings have both theoretical and practical implications for the study of SRM, stress disorders, and health.

Treating necrotizing fasciitis with or without hyperbaric oxygen therapy.

There is not enough clinical data to support the benefit of adjuvant HBO2 therapy for necrotizing fasciitis (NF). We retrospectively reviewed our 67 NF cases to compare the outcomes of adjuvant HBO2 therapy versus non-HBO2 therapy. The overall outcome and morbidity criteria were compared between a group of 29 NF patients who received the adjuvant HBO2 and a group of the remaining 38 NF patients treated by only surgery and other standards of care. This study did not find any difference between the groups in average length of hospital stay, and their mortality. However, six (25%) of the non-HBO2 group patients required amputation of extremities compared to one of the HBO2 group (Fisher exact p = 0.09). Although the benefit of adjuvant HBO2 therapy remains controversial for NF, and the outcomes of this study are not statistically significant, there is a trend in clinical outcomes which shows that the therapy has the potential to reduce the number of amputation and salvage extremities. These findings necessitate multicenter, prospective, case control study to assess the possible benefit of adjuvant HBO2 therapy for NF.

Autonomic specificity of basic emotions: evidence from pattern classification and cluster analysis.

Autonomic nervous system (ANS) specificity of emotion remains controversial in contemporary emotion research, and has received mixed support over decades of investigation. This study was designed to replicate and extend psychophysiological research, which has used multivariate pattern classification analysis (PCA) in support of ANS specificity. Forty-nine undergraduates (27 women) listened to emotion-inducing music and viewed affective films while a montage of ANS variables, including heart rate variability indices, peripheral vascular activity, systolic time intervals, and electrodermal activity, were recorded. Evidence for ANS discrimination of emotion was found via PCA with 44.6% of overall observations correctly classified into the predicted emotion conditions, using ANS variables (z=16.05, p<.001). Cluster analysis of these data indicated a lack of distinct clusters, which suggests that ANS responses to the stimuli were nomothetic and stimulus-specific rather than idiosyncratic and individual-specific. Collectively these results further confirm and extend support for the notion that basic emotions have distinct ANS signatures.

Cardiovascular activity during laboratory tasks in women with high and low worry.

Worry has been related to delayed stress recovery and cardiovascular disease risk. Cardiovascular responses to a range of laboratory tasks were examined in this study of high and low worriers. Undergraduate women were recruited with the Penn State Worry Questionnaire to form low (n=19) and high (n=22) worry groups. These individuals engaged in six laboratory tasks (orthostatic stress, supine rest, hand cold pressor, mental arithmetic, and worry and relaxation imagery) while heart rate (HR), HR spectral analysis, impedance cardiography, and blood pressure were acquired. The only significant group difference found was a consistently greater HR across tasks in high worriers (p<.05). No group by condition interactions emerged. High trait worry in healthy young women appears to be marked by elevated HR in the absence of autonomic abnormalities. These findings are discussed relative to the literature on worry, with particular reference to its health implications.