Disturbed Microbiome Clinically Detrimental in ICU

Patients in the intensive care unit with an imbalanced microbiome are at increased risk for complications and longer ICU stays, according to findings presented at Clinical Nutrition Week 2017 | Anesthesiology News

B0011080 Bacterial microbiome mapping, bioartistic experiment

Image source: François-Joseph Lapointe, Université de Montréal – Wellcome Images // CC BY 4.0

Image shows bacterial microbiome mapping – a bioartistic experiment.

Paul Wischmeyer, MD, professor of anesthesiology and surgery and director of perioperative research at Duke Clinical Research Institute, in Durham, N.C., who also is part of the ICU Microbiome Project, told meeting attendees that ICU patients experience significant microbiome perturbations and added complications, including acute respiratory distress syndrome (ARDS).

“ICU patients have massive loss of health-promoting bacteria and higher levels of pathogenic species, compared with healthy patients,” Dr. Wischmeyer said. “It is astonishing how rapidly pathogenic bacteria flourish and how this shift to dysbiosis appears to affect a variety of outcomes.”

Dr. Wischmeyer and his colleagues have been examining fecal and oral microbiome samples from 115 ICU patients treated at four hospitals and comparing them with samples from healthy people participating in the American Gut project. In previous research, they found decreases in populations of Bacteroides and Firmicutes, as well as the healthy bacterium, Faecalibacterium prausnitzii, which produces short-chain fatty acids that help preserve normal gut barrier function (mSphere 2016;1[4]. pii:e00199-16). Meanwhile, they discovered increases in the relative abundance of Proteobacteria, a phylum of gram-negative bacteria linked to infections in ICU and hospitalized patients.

ICU patients also tended to lose overall fecal microbiota diversity, with some patients having only one organism compose 95% of their fecal bacteria after a short time in the ICU, he explained.

Muscle mass and physical recovery in ICU

We have significantly improved hospital mortality from sepsis and critical illness in last 10 years; however, over this same period we have tripled the number of ‘ICU survivors’ going to rehabilitation | Current Opinion in Critical Care


Furthermore, as up to half the deaths in the first year following ICU admission occur post-ICU discharge, it is unclear how many of these patients ever returned home or a meaningful quality of life. For those who do survive, recent data reveals many ‘ICU survivors’ will suffer significant functional impairment or post-ICU syndrome (PICS). Thus, new innovative metabolic and exercise interventions to address PICS are urgently needed. These should focus on optimal nutrition and lean body mass (LBM) assessment, targeted nutrition delivery, anabolic/anticatabolic strategies, and utilization of personalized exercise intervention techniques, such as utilized by elite athletes to optimize preparation and recovery from critical care.

New data for novel LBM analysis technique such as computerized tomography scan and ultrasound analysis of LBM are available showing objective measures of LBM now becoming more practical for predicting metabolic reserve and effectiveness of nutrition/exercise interventions. 13C-Breath testing is a novel technique under study to predict infection earlier and predict over-feeding and under-feeding to target nutrition delivery. New technologies utilized routinely by athletes such as muscle glycogen ultrasound also show promise. Finally, the role of personalized cardiopulmonary exercise testing to target preoperative exercise optimization and post-ICU recovery are becoming reality.

Full reference: Wischmeyer, P.E. et al. (2017) Muscle mass and physical recovery in ICU: innovations for targeting of nutrition and exercise. Current Opinion in Critical Care: Published online: June 7, 2017

Electrolyte abnormalities in critically ill patients with end-stage renal disease receiving parenteral nutrition

Dotson, B & Vulaj, V. Journal of Critical Care | Published online: 27 April 2017

Malnutrition is common in patients who are critically ill and is associated with increased morbidity and mortality. For patients unable to receive enteral nutrition, the use of parenteral nutrition (PN) can be life-saving. PN is a complex formulation containing macronutrients, electrolytes, and micronutrients, and critical care clinicians are frequently involved in writing PN orders for patients in the intensive care unit (ICU).

Read the abstract here

Nurses’ prioritization of enteral nutrition in intensive care units

Bloomer, M. J et al. Nursing in Critical Care. Published online: 30 January 2017


Background: Enteral nutrition is important in critically ill patients to improve patient outcomes, with nurses playing a pivotal role in the delivery and ongoing care of enteral nutrition. A significant deficit in nurses’ knowledge and education relating to enteral nutrition has been identified, leading to iatrogenic malnutrition and potentially compromising patient care. Enteral nutrition appears to be prioritized lower than many other aspects of care. However, there is scant research to show how nurses prioritize enteral nutrition.

Conclusion:Respondents relied on their clinical judgement to inform decisions in relation to enteral nutrition in critically ill patients. Most respondents agreed that enteral nutrition was an important aspect of patient care, but acknowledged that other aspects of care were prioritized more highly. Despite this, some delays to enteral nutrition were perceived to be avoidable, and nurses recognized a need to advocate on the patient’s behalf to increase the visibility of enteral nutrition.

Relevance to clinical practice: The findings of this study demonstrate that enteral nutrition is often prioritized lower than other competing care needs in the critically ill patient. Given the importance of enteral nutrition to patient recovery, changes to clinical practice to improve enteral nutrition management are necessary.

Read the full abstract here

Parental nutrition in the critically ill.

Gunst, Jan; Van den Berghe, Greet. Parenteral nutrition in the critically ill. Current Opinion in Critical Care. January 2017

Purpose of review: Feeding guidelines have recommended early, full nutritional support in critically ill patients to prevent hypercatabolism and muscle weakness. Early enteral nutrition was suggested to be superior to early parenteral nutrition. When enteral nutrition fails to meet nutritional target, it was recommended to administer supplemental parenteral nutrition, albeit with a varying starting point. Sufficient amounts of amino acids were recommended, with addition of glutamine in subgroups. Recently, several large randomized controlled trials (RCTs) have yielded important new insights.
This review summarizes recent evidence with regard to the indication, timing, and dosing of parenteral nutrition in critically ill patients.

Recent findings: One large RCT revealed no difference between early enteral nutrition and early parenteral nutrition. Two large multicenter RCTs showed harm by early supplementation of insufficient enteral nutrition with parenteral nutrition, which could be explained by feeding-induced suppression of autophagy. Several RCTs found either no benefit or harm with a higher amino acid or caloric intake, as well as harm by administration of glutamine.

Summary: Although unanswered questions remain, current evidence supports accepting low macronutrient intake during the acute phase of critical illness and does not support use of early parenteral nutrition. The timing when parenteral nutrition can be initiated safely and effectively is unclear.

Resting energy expenditure, calorie and protein consumption in critically ill patients

Zusman, O. et al. Critical Care. Published: 10 November 2016

Background: Intense debate exists regarding the optimal energy and protein intake for intensive care unit (ICU) patients. However, most studies use predictive equations, demonstrated to be inaccurate to target energy intake. We sought to examine the outcome of a large cohort of ICU patients in relation to the percent of administered calories divided by resting energy expenditure (% AdCal/REE) obtained by indirect calorimetry (IC) and to protein intake.

Methods: Included patients were hospitalized from 2003 to 2015 at a 16-bed ICU at a university affiliated, tertiary care hospital, and had IC measurement to assess caloric targets. Data were drawn from a computerized system and included the % AdCal/REE and protein intake and other variables. A Cox proportional hazards model for 60-day mortality was used, with the % AdCal/REE modeled to accommodate non-linearity. Length of stay (LOS) and length of ventilation (LOV) were also assessed.

Results: A total of 1171 patients were included. The % AdCal/REE had a significant non-linear (p < 0.01) association with mortality after adjusting for other variables (p < 0.01). Increasing the percentage from zero to 70 % resulted in a hazard ratio (HR) of 0.98 (CI 0.97–0.99) pointing to reduced mortality, while increases above 70 % suggested an increase in mortality with a HR of 1.01 (CI 1.01–1.02). Increasing protein intake was also associated with decreased mortality (HR 0.99, CI 0.98–0.99, p = 0.02). An AdCal/REE >70 % was associated with an increased LOS and LOV.

Conclusions: The findings of this study suggest that both underfeeding and overfeeding appear to be harmful to critically ill patients, such that achieving an Adcal/REE of 70 % had a survival advantage. A higher caloric intake may also be associated with harm in the form of increased LOS and LOV. The optimal way to define caloric goals therefore requires an exact estimate, which is ideally performed using indirect calorimetry. These findings may provide a basis for future randomized controlled trials comparing specific nutritional regimens based on indirect calorimetry measurements.

Read the full article here

Lower versus higher dose of enteral caloric intake in adult critically ill patients: a systematic review and meta-analysis

Al-Dorzi, H. M. et al. Critical Care. Published online: 4 November 2016

Background: There is conflicting evidence about the relationship between the dose of enteral caloric intake and survival in critically ill patients. The objective of this systematic review and meta-analysis is to compare the effect of lower versus higher dose of enteral caloric intake in adult critically ill patients on outcome.

Methods: We reviewed MEDLINE, EMBASE, Cochrane Central Register of Controlled Trials, Cochrane Database of Systematic Reviews, and Scopus from inception through November 2015. We included randomized and quasi-randomized studies in which there was a significant difference in the caloric intake in adult critically ill patients, including trials in which caloric restriction was the primary intervention (caloric restriction trials) and those with other interventions (non-caloric restriction trials). Two reviewers independently extracted data on study characteristics, caloric intake, and outcomes with hospital mortality being the primary outcome.

Results: Twenty-one trials mostly with moderate bias risk were included (2365 patients in the lower caloric intake group and 2352 patients in the higher caloric group). Lower compared with higher caloric intake was not associated with difference in hospital mortality (risk ratio (RR) 0.953; 95 % confidence interval (CI) 0.838–1.083), ICU mortality (RR 0.885; 95 % CI 0.751–1.042), total nosocomial infections (RR 0.982; 95 % CI 0.878–1.077), mechanical ventilation duration, or length of ICU or hospital stay. Blood stream infections (11 trials; RR 0.718; 95 % CI 0.519–0.994) and incident renal replacement therapy (five trials; RR 0.711; 95 % CI 0.545–0.928) were lower with lower caloric intake. The associations between lower compared with higher caloric intake and primary and secondary outcomes, including pneumonia, were not different between caloric restriction and non-caloric restriction trials, except for the hospital stay which was longer with lower caloric intake in the caloric restriction trials.

Conclusions: We found no association between the dose of caloric intake in adult critically ill patients and hospital mortality. Lower caloric intake was associated with lower risk of blood stream infections and incident renal replacement therapy (five trials only). The heterogeneity in the design, feeding route and timing and caloric dose among the included trials could limit our interpretation. Further studies are needed to clarify our findings.

Read the full article here