Supplemental parenteral nutrition in the critically ill patient: a retrospective study

Review of evolution and current status of protein requirements and provision in acute illness and critical care

Nutrition therapy, by enteral, parenteral, or both routes combined, is a key component of the management of critically ill, surgical, burns, and oncology patients. Established evidence indicates overfeeding (provision of excessive calories) results in increased risk of infection, morbidity, and mortality. This has led to the practice of "permissive underfeeding" of calories; however, this can often lead to inadequate provision of guideline-recommended protein intakes. Acutely ill patients requiring nutritional therapy have high protein requirements, and studies demonstrate that provision of adequate protein can result in reduced mortality and improvement in quality of life. However, a significant challenge to adequate protein delivery is the current lack of concentrated protein solutions. Patients often have fluid administration restrictions and existing protein solutions are frequently not sufficiently concentrated to deliver a patient's protein requirements. This has led to the development of new enteral and parenteral nutrition solutions incorporating higher levels of protein in smaller volumes. This review article summarizes current evidence supporting the role of higher protein intakes, especially during the early phases of nutrition therapy in acute illness, methods for assessing protein requirements, as well as, the currently available high-protein enteral and parenteral nutrition solutions. There is sufficient evidence (albeit limited from true randomized, controlled studies) to indicate that earlier provision of guideline-recommended protein intakes may be key to improving patient outcomes and that nutritional therapy that tailors caloric and protein intake to the patients' needs should be considered a desired standard of care.

Effect of Supplemental Parenteral Nutrition Versus Enteral Nutrition Alone on Clinical Outcomes in Critically Ill Adult Patients: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

Enteral nutrition (EN) is considered the first feeding route for critically ill patients. However, adverse effects such as gastrointestinal complications limit its optimal provision, leading to inadequate energy and protein intake. We compared the clinical outcomes of supplemental parenteral nutrition added to EN (SPN + EN) and EN alone in critically ill adults. Electronic databases restricted to full-text randomized controlled trials available in the English language and published from January 1990 to January 2019 were searched. The risk of bias was evaluated using the Jadad scale, and the meta-analysis was conducted using the MedCalc software. A total of five studies were eligible for inclusion in the systematic review and meta-analysis. Compared to EN alone, SPN + EN decreased the risk of nosocomial infections (relative risk (RR) = 0.733, p = 0.032) and intensive care unit (ICU) mortality (RR = 0.569, p = 0.030). No significant differences were observed between SPN + EN and EN in the length of hospital stay, hospital mortality, length of ICU stay, and duration of mechanical ventilation. In conclusion, when enteral feeding fails to fulfill the energy requirements in critically ill adult patients, SPN may be beneficial as it helps in decreasing nosocomial infections and ICU mortality, in addition to increasing energy and protein intakes with no negative effects on other clinical outcomes.

Combination enteral and parenteral nutrition in critically ill patients: harmful or beneficial? A systematic review of the evidence

OBJECTIVE

A combination of enteral (EN) and parenteral nutrition (PN) is often used as a strategy to optimize nutritional intake in critically ill patients; however, the effects of this intervention on clinically important outcomes have not been widely studied. This paper systematically reviewed studies that compare EN + PN to enteral nutrition (EN) alone in critically ill patients.

METHODS

We searched bibliographic databases, personal files, and relevant reference lists to identify randomized controlled trials that compared combination EN + PN to EN alone.

RESULTS

Only five studies met the inclusion criteria. In all these studies PN was started at the same time as EN in the experimental group. When the results of these trials were aggregated, EN + PN had no significant effect on mortality. There was no difference between the two groups in rates of infectious complications, length of hospital stay, or ventilator days.

CONCLUSIONS

In critically ill patients who are not malnourished and have an intact gastrointestinal tract, starting PN at the same time as EN provides no benefit in clinical outcomes over EN alone. More research is needed to determine the effects of combination EN + PN on clinical outcomes in critically ill patients who are poorly intolerant to EN.

Parenteral nutrition in the critically-ill patient: more harm than good?

While many studies have reported that providing parenteral nutrition (PN) can change nutritional outcomes, there are limited data that demonstrate that PN influences clinically-important end points in critically-ill patients. The purpose of the present paper is to systematically review and critically appraise the literature to examine the relationship between PN and morbidity and mortality in the critically-ill patient. Studies comparing enteral nutrition (EN) with PN and studies comparing PN with no PN were reviewed. The results suggest that EN is associated with reduced infectious complications in some critically-ill subgroups. PN, on the other hand, is associated with increased morbidity and mortality in critically-ill patients. When nutritional support is indicated, EN should be used preferentially over PN. Further studies are needed to define the optimal timing and composition of PN in patients not tolerating sufficient EN. Strategies to optimize EN delivery and minimize PN utilization in critically-ill patients are indicated.