Parenteral nutrition in the ICU: Lessons learned over the past few years

Comparison of two isocaloric parenteral nutrition regimens with different protein content - A propensity-score matched comparative study

Introduction

Objective: this study aimed to assess the effects of two isocaloric parenteral nutrition (PN) regimens with different protein content and non-protein calorie to nitrogen ratio (NPCNR) on the evolution of nutritional parameters and outcomes in adult inpatients. Methods: this was a retrospective quasi-experimental study performed in a 400-bed tertiary hospital. Adult inpatients were initially eligible if they had received ≥ 4 days of PN with NPCNR ≥ 100 or ≤ 90 in a period of three years. Patients were propensity-score matched to adjust for differences, resulting in two final cohorts: Cohort "Medium-P" included patients receiving PN with NCPCNR ≥ 100 and cohort "High-P", receiving PN with NCPCNR ≤ 90. The main variables were differences in plasma albumin, prealbumin, cholesterol, and lymphocyte count, days requiring PN, length of stay, and mortality at 90 days. Results: 202 patients were finally recruited and divided into the two equal cohorts. Patients were mainly male (122; 60.4 %), surgical (149; 73.8 %), critically ill (100; 49.5 %), with high nutritional risk (141; 69.8 %) and with a neoplasm (145; 71.8 %). PN provided 25 kcal/kg/day, but protein intake was 0.25 g/kg/day higher in the "High-P" cohort. Baseline characteristics and biochemistry were not different between the two cohorts. The "High-P" cohort presented a smaller difference at the end of PN for lymphocytes, more days with hyperglycaemia, and more days requiring PN. The rest of variables did not differ. Conclusions: high doses of protein (lower NPCNR) did not present advantages compared to medium doses of protein (higher NPCNR) when providing isocaloric PN in adult inpatients.

Parenteral Nutrition: Current Use, Complications, and Nutrition Delivery in Critically Ill Patients

BACKGROUND

Parenteral nutrition (PN) is needed to avoid the development of malnutrition when enteral nutrition (EN) is not possible. Our main aim was to assess the current use, complications, and nutrition delivery associated with PN administration in adult critically ill patients, especially when used early and as the initial route. We also assessed the differences between patients who received only PN and those in whom EN was initiated after PN (PN-EN).

METHODS

A multicenter (n = 37) prospective observational study was performed. Patient clinical characteristics, outcomes, and nutrition-related variables were recorded. Statistical differences between subgroups were analyzed accordingly.

RESULTS

From the entire population (n = 629), 186 (29.6%) patients received PN as initial nutrition therapy. Of these, 74 patients (11.7%) also received EN during their ICU stay (i.e., PN-EN subgroup). PN was administered early (<48 h) in the majority of patients (75.3%; n = 140) and the mean caloric (19.94 ± 6.72 Kcal/kg/day) and protein (1.01 ± 0.41 g/kg/day) delivery was similar to other contemporary studies. PN showed similar nutritional delivery when compared with the enteral route. No significant complications were associated with the use of PN. Thirty-two patients (43.3%) presented with EN-related complications in the PN-EN subgroup but received a higher mean protein delivery (0.95 ± 0.43 vs 1.17 ± 0.36 g/kg/day; p = 0.03) compared with PN alone. Once adjusted for confounding factors, patients who received PN alone had a lower mean protein intake (hazard ratio (HR): 0.29; 95% confidence interval (CI): 0.18-0.47; p = 0.001), shorter ICU stay (HR: 0.96; 95% CI: 0.91-0.99; p = 0.008), and fewer days on mechanical ventilation (HR: 0.85; 95% CI: 0.81-0.89; p = 0.001) compared with the PN-EN subgroup.

CONCLUSION

The parenteral route may be safe, even when administered early, and may provide adequate nutrition delivery. Additional EN, when possible, may optimize protein requirements, especially in more severe patients who received initial PN and are expected to have longer ICU stays. NCT Registry: 03634943.

Gastrointestinal dysfunction is associated with mortality in severe burn patients: a 10-year retrospective observational study from South China

BACKGROUND

Data on severe and extensive burns in China are limited, as is data on the prevalence of a range of related gastrointestinal (GI) disorders [such as stress ulcers, delayed defecation, opioid-related bowel immotility, and abdominal compartment syndrome (ACS)]. We present a multicentre analysis of coincident GI dysfunction and its effect on burn-related mortality.

METHODS

This retrospective analysis was conducted on patients with severe [≥ 20% total burn surface area (TBSA)] and extensive (> 50% TBSA or > 25% full-thickness TBSA) burns admitted to three university teaching institutions in China between January 1, 2011 and December 31, 2020. Both 30- and 90-day mortality were assessed by collating demographic data, burn causes, admission TBSA, % full-thickness TBSA, Baux score, Abbreviated Burn Severity Index (ABSI) score, and Sequential Organ Failure Assessment (SOFA) score, shock at admission and the presence of an inhalation injury. GI dysfunction included abdominal distension, nausea/vomiting, diarrhoea/constipation, GI ulcer/haemorrhage, paralytic ileus, feeding intolerance and ACS. Surgeries, length of intensive care unit (ICU) stay, pain control [in morphine milligram equivalents (MME)] and overall length of hospital stay (LOHS) were recorded.

RESULTS

We analyzed 328 patients [75.6% male, mean age: (41.6 ± 13.6) years] with a median TBSA of 62.0% (41.0-80.0%); 256 (78.0%) patients presented with extensive burns. The 90-day mortality was 23.2% (76/328), with 64 (84.2%) of these deaths occurring within 30 d and 25 (32.9%) occurring within 7 d. GI dysfunction was experienced by 45.4% of patients and had a significant effect on 90-day mortality [odds ratio (OR) = 14.070, 95% confidence interval (CI) 5.886-38.290, P < 0.001]. Multivariate analysis showed that GI dysfunction was associated with admission SOFA score and % full-thickness TBSA. Overall, 88.2% (67/76) of deceased patients had GI dysfunction [hazard ratio (HR) for death of GI dysfunction = 5.951], with a survival advantage for functional disorders (diarrhoea, constipation, or nausea/vomiting) over GI ulcer/haemorrhage (P < 0.001).

CONCLUSION

Patients with severe burns have an unfavourable prognosis, as nearly one-fifth died within 90 d. Half of our patients had comorbidities related to GI dysfunction, among which GI ulcers and haemorrhages were independently correlated with 90-day mortality. More attention should be given to severe burn patients with GI dysfunction.

Enteral Nutrition in Critically Ill Patients Under Vasoactive Drug Therapy. The NUTRIVAD Study

BACKGROUND

Enteral nutrition (EN) in critically ill patients requiring vasoactive drug (VAD) support is controversial. This study assesses the tolerability and safety of EN in such patients.

METHODS

This prospective observational study was conducted in 23 ICUs over 30 months. Inclusion criteria were a need for VAD and/or mechanic circulatory support (MCS) over a minimum of 48 h, a need for at least 48 h of mechanical ventilation, an estimated life expectancy longer than 72 h, and at least 72 h of ICU stay. Patients with refractory shock were excluded. EN was performed according to established protocols during which descriptive, daily hemodynamic and efficacy and safety data were collected. An independent research group conducted the statistical analysis.

RESULTS

Of 200 patients included, 30 (15%) required MCS and 145 (73%) met early multiorgan dysfunction criteria. Mortality was 24%. Patients needed a mean dose of norepinephrine in the first 48 h of 0.71 μg/kg/min (95%CI: 0.63-0.8) targeting a mean arterial pressure of 68 mmHg (95%CI: 67-70) during the first 48 h. EN was started 34 h (95%CI: 31-37) after ICU admission. Mean energy and protein delivered by EN/patient/day were 1159 Kcal (95%CI: 1098-1220) and 55.6 g (52.4-58.7) respectively. Daily energy balance during EN/patient/day was -432 (95%CI: -496 to -368). 154 (77%) patients experienced EN-related complications. However, severe complications such as mesenteric ischemia were recorded in only 1 patient (0.5%).

CONCLUSIONS

EN in these patients seems feasible, safe and unrelated to serious complications. Reaching the energy target only through EN is difficult.

CLINICAL RELEVANCY STATEMENT

Enteral nutrition (EN) in critically ill patients requiring vasoactive drugs (VAD) is currently a subject of controversy. Factors such as when to start EN, dosing, monitoring, or whether to avoid EN altogether are a real challenge because of its link to a risk of bowel ischemia. We describe our experience with EN in 200 critically ill patients on mechanical ventilation and requiring VAD. Under adequate supervision, EN proved feasible and safe. Our findings require confirmation in clinical intervention trials. This article is protected by copyright. All rights reserved.

When is parenteral nutrition indicated?

The indications and contraindications of parenteral nutrition (PN) are discussed in view of recent clinical findings. For decades, PN has been restricted to patients unable to tolerate enteral nutrition (EN) intake owing to the perceived risk of severe side-effects. The evolution of the PN substrate composition and delivery of nutrition via all-in-one bags has dramatically improved the application prospects of PN. Recent studies show similar complication rates of nutrition therapy administered through enteral and intravenous routes. Therefore, indications of PN have, based on evidence, extended beyond complete gastrointestinal (GI) failure to include conditions such as insufficient EN generating persistent negative energy balance and insufficient protein intakes, malabsorption, or specific needs that are impossible to cover with EN feeds.

Effect of Early Versus Delayed Parenteral Nutrition on the Health Outcomes of Critically Ill Adults: A Systematic Review

Objectives

This systematic review aims to evaluate and summarise the findings of all relevant studies which identified the effect of early vs delayed parenteral nutrition (PN), early PN vs early supplemental PN and early PN vs standard care for critically ill adults.

Methods

The literature search was undertaken using PubMed, Embase, Medline, Clinical Key, and Ovid discovery databases. The reference lists of studies published from 2000 till June 2020 were hand searched.

Result

On screening 2088 articles, a total of five RCTs with 6,277 patients were included in this review. Only one clinical trial compared early PN and late PN; the results reported significantly shorter periods in intensive care unit (ICU) stay (p=0.02) and less ICU related infections (p=0.008) in the late PN group compared to the Early PN group. Two trials compared total parenteral nutrition (TPN) and enteral nutrition (EN) +TPN groups. Both found a significantly longer hospital stay duration (p<0.05 and p<0.01) with a higher mortality rate in the TPN group compared to the EN+TPN group. A statistically significant improvement was observed in patients' quality of life receiving early PN compared to standard care (p=0.01). In contrast, no significant difference was found in the supplemental PN vs the standard care group.

Conclusion

The supplemental PN patients had shorter ICU stay and lower mortality rates than TPN. However, these findings should be interpreted carefully as included studies have different initiation timing of nutritional support, and the patients' diagnosis varied.

Caloric Intake with High Ratio of Enteral Nutrition Associated with Lower Hospital Mortality for Patients with Acute Respiratory Distress Syndrome Using Prone Position Therapy

Positioning patients in the prone position leads to reduced hospital mortality rates for those with severe acute respiratory distress syndrome (ARDS). What constitutes the optimal feeding strategy for prone patients with ARDS is controversial. We conducted a retrospective study that enrolled 110 prone patients with ARDS in two medical intensive care units (ICUs) from September 2015 to November 2018. Inclusion criteria were as follows: age ≥20 years, diagnosis of respiratory failure requiring mechanical ventilation, diagnosis of ARDS within 72 h of ICU admission, placement in a prone position within the first 7 days of ICU admission, and ICU stay of more than 7 days. Exclusion criteria were as follows: nil per os orders because of gastrointestinal bleeding or hemodynamic instability, and ventilator dependency because of chronic respiratory failure. The consecutive daily enteral nutrition(EN)/EN + parenteral nutrition(PN) ratio could predict hospital mortality rates within the first 7 days of admission when using generalized estimating equations (p = 0.013). A higher average EN/EN + PN ratio within the first 7 days predicted (hazard ratio: 0.97, confidence interval: 0.96-0.99) lower hospital mortality rates. To reduce hospital mortality rates, caloric intake with a higher EN ratio may be considered for patients in prone positions with ARDS.

Combination of enteral and parenteral nutrition in the acute phase of critical illness: An updated systematic review and meta-analysis

BACKGROUND

Uncertainty remains about the best route and timing of medical nutrition therapy in the acute phase of critical illness. Early combined enteral nutrition (EN) and parenteral nutrition (PN) may represent an attractive option to achieve recommended energy and protein goals in select patient groups. This meta-analysis aims to update and summarize the current evidence.

METHODS

This systematic review and meta-analysis includes randomized controlled trials (RCTs) targeting the effect of EN alone vs a combination of EN with PN in the acute phase of critical illness in adult patients. Assessed outcomes include mortality, intensive care unit (ICU) and hospital length of stay (LOS), ventilation days, infectious complications, physical recovery, and quality-of-life outcomes.

RESULTS

Twelve RCTs with 5543 patients were included. Treatment with a combination of EN with PN led to increased delivery of macronutrients. No statistically significant effect of a combination of EN with PN vs EN alone on any of the parameters was observed: mortality (risk ratio = 1.0; 95% CI, 0.79-1.28; P = .99), hospital LOS (mean difference, -1.44; CI, -5.59 to 2.71; P = .50), ICU LOS, and ventilation days. Trends toward improved physical outcomes were observed in two of four trials.

CONCLUSION

A combination of EN with PN improved nutrition intake in the acute phase of critical illness in adults and was not inferior regarding the patients' outcomes. Large, adequately designed trials in select patient groups are needed to answer the question of whether this nutrition strategy has a clinically relevant treatment effect.

Parenteral nutrition in critical illness: total, supplemental or never?

PURPOSE OF REVIEW

The current review summarizes recent evolutions in knowledge and discusses the concept of whom and when parenteral nutrition should be considered in critically ill patients as a total form of nutrition, in a supplemental form, or never.

RECENT FINDINGS

Recent developments in our understanding of the application of parenteral nutrition in critical care include the phases of illness, avoidance of overfeeding and the population in whom parenteral nutrition may be appropriate for. Importantly, one of the greatest lessons of recent times may be who not to provide parenteral nutrition to; however, a blanket approach of increased risk with parenteral nutrition is too simple for the modern context.

SUMMARY

When providing total or supplemental parenteral nutrition, avoidance of overfeeding with total calories and/or glucose alone is critical, as is consideration to the phase of illness the patient is in, the population in whom it is to be applied, premorbid nutrition status and the setting (including adequacy of line management and expertise in parenteral nutrition provision). The appropriateness of parenteral nutrition should be considered in those where death is imminent or who are well nourished, likely to commence oral and/or enteral nutrition imminently and have a short-stay in intensive care, or are in a high-risk setting.

First international meeting of early career investigators: Current opportunities, challenges and horizon in critical care nutrition research

BACKGROUND

Appropriate nutritional support is a key component of care for critically ill patients. While malnutrition increases complications, impacting long term outcomes and healthcare-related costs, uncertainties persist regarding optimal provision of nutritional support in this setting.

METHODS

An international group of healthcare providers (HCPs) from critical care specialties and nutrition researchers convened to identify knowledge gaps and learnings from studies in critical care nutrition. Clinical research needs were identified in order to better inform future nutrition practices.

RESULTS

Challenges in critical care nutrition arise, in part, from inconsistent outcomes in several large-scale studies regarding the optimal amount of calories and protein to prescribe, the optimal time to initiate nutritional support and the role of parental nutrition to support critically ill patients. Furthermore, there is uncertainty on how best to identify patients at nutritional risk, and the appropriate outcome measures for ICU nutrition studies. Given HCPs have a suboptimal evidence base to inform the nutritional management of critically ill patients, further well-designed clinical trials capturing clinically relevant endpoints are needed to address these knowledge gaps.

CONCLUSIONS

The identified aspects for future research could be addressed in studies designed and conducted in collaboration with an international team of interdisciplinary nutrition experts. The aim of this collaboration is to address the unmet need for robust clinical data needed to develop high-quality evidence-based nutritional intervention recommendations to better inform the future management of critically ill patients.

Nutrition and Micronutrient Therapy in Critical Illness Should Be Individualized

Critically ill (intensive care unit [ICU]) patients are characterized by organ failure, intense inflammatory response, insulin resistance, and altered metabolic response. The sicker the patient, the higher the threat to nutrition and micronutrient status. In addition, many patients start the ICU stay with an altered nutrition status, which requires assessment upon admission. Nutrition needs vary among patients as well as during hospitalization, as the metabolic response changes over time. Shock and acute organ failure result in a metabolic shift toward intense catabolism: endogenous glucose production aiming at ensuring the basal adenosine triphosphate production starts immediately and occurs at the expense of the lean body mass using amino acids for neoglucogenesis. Later, the stabilization and recovery phases are characterized by higher energy and substrate needs. Indirect calorimetry is the only tool enabling determination of the metabolic level. When and how should feeding be started? Recent research shows that the route does not matter much, with equipoise between enteral and parenteral nutrition (PN) as long as overfeeding is avoided. As micronutrients are an integral part of metabolism and antioxidant defenses, their delivery must be ensured: whereas needs are well defined for healthy individuals, needs for illness remain poorly defined. PN that contains only macrosubstrates requires the daily prescription of multimicronutrient complements to qualify as total PN. Achievement of goals requires minimal monitoring, consisting of the daily verification of energy and protein goal delivery achievement and daily follow-up determining blood glucose and phosphate levels and insulin requirements.

How to choose the best route of feeding during critical illness

Increased and specific nutritional requirements occurring during critical illness need to be covered by appropriate administration of energy, nitrogen and micronutrients, especially in case of pre-existing malnutrition, chronic insufficient oral intakes or expected delay before recovery of eating. The use of artificial nutrition (enteral or parenteral) is recommended whenever the oral intakes are insufficient, in order to avoid the detrimental consequences of malnutrition and promote the best possible outcome of severely ill patients. This paper aims to provide an overview and practical recommendations of artificial nutrition therapy in the ICU setting.

Medical Nutrition Therapy in Critically Ill Patients Treated on Intensive and Intermediate Care Units: A Literature Review

Medical nutrition therapy in critically ill patients remains challenging, not only because of the pronounced stress response with a higher risk for complications, but also due to their heterogeneity evolving from different phases of illness. The present review aims to address current knowledge and guidelines in order to summarize how they can be best implemented into daily clinical practice. Further studies are urgently needed to answer such important questions as best timing, route, dose, and composition of medical nutrition therapy for critically ill patients and to determine how to assess and to adapt to patients’ individual needs.

Indirect Calorimetry in Clinical Practice

Indirect calorimetry (IC) is considered as the gold standard to determine energy expenditure, by measuring pulmonary gas exchanges. It is a non-invasive technique that allows clinicians to personalize the prescription of nutrition support to the metabolic needs and promote a better clinical outcome. Recent technical developments allow accurate and easy IC measurements in spontaneously breathing patients as well as in those on mechanical ventilation. The implementation of IC in clinical routine should be promoted in order to optimize the cost–benefit balance of nutrition therapy. This review aims at summarizing the latest innovations of IC as well as the clinical indications, benefits, and limitations.

Metabolic and Nutritional Characteristics of Long-Stay Critically Ill Patients

Background: insufficient feeding is frequent in the intensive care unit (ICU), which results in poor outcomes. Little is known about the nutrition pattern of patients requiring prolonged ICU stays. The aims of our study are to describe the demographic, metabolic, and nutritional specificities of chronically critically ill (CCI) patients defined by an ICU stay >2 weeks, and to identify an early risk factor. Methods: analysis of consecutive patients prospectively admitted to the CCI program, with the following variables: demographic characteristics, Nutrition Risk Screening (NRS-2002) score, total daily energy from nutritional and non-nutritional sources, protein and glucose intakes, all arterial blood glucose values, length of ICU and hospital stay, and outcome (ICU and 90-day survival). Two phases were considered for the analysis: the first 10 days, and the next 20 days of the ICU stay. Statistics: parametric and non-parametric tests. Results: 150 patients, aged 60 ± 15 years were prospectively included. Median (Q1, Q3) length of ICU stay was 31 (26, 46) days. The mortality was 18% at ICU discharge and 35.3% at 90 days. Non-survivors were older (p = 0.024), tended to have a higher SAPSII score (p = 0.072), with a significantly higher NRS score (p = 0.033). Enteral nutrition predominated, while combined feeding was minimally used. All patients received energy and protein below the ICU’s protocol recommendation. The proportion of days with fasting was 10.8%, being significantly higher in non-survivors (2 versus 3 days; p = 0.038). Higher protein delivery was associated with an increase in prealbumin over time (r² = 0.19, p = 0.027). Conclusions: High NRS scores may identify patients at highest risk of poor outcome when exposed to underfeeding. Further studies are required to evaluate a nutrition strategy for patients with high NRS, addressing combined parenteral nutrition and protein delivery.