Protein requirements, morbidity and mortality in critically ill patients: fundamentals and applications

Is there a relationship between nutritional goal achievement and pressure injury risk in intensive care unit patients receiving enteral nutrition?

OBJECTIVES

To assess pressure injury risk and time until pressure injury development according to the achievement of nutritional goals, i.e. caloric and protein intake within the first 72 hours of the intensive care admission.

METHOD

Prospective observational cohort study conducted in two units at a public university hospital. The development of pressure injury was considered the dependent variable. Survival curves were prepared with the Kaplan Meier method. Univariate and multivariate Cox regression analysis was used to identify factors associated with the development of pressure injury.

RESULTS

The study sample included 181 patients, of which 56.4% were male and the average age was 55 years. Neurological pathologies were the most frequent cause of hospitalisation (44.8%). The average length of stay was 17.5 days and mortality 30.4%. With regards to nutritional goals, 105 patients (58.0%) achieved their caloric goal, 130 (71.8%) achieved protein goals, and 98 (54.1%) achieved both. The frequency of pressure injury occurrence was 31.5%. Caloric intake (hazard ratio [HR] 2.3, 95% confidence interval [CI] 1.24-4.36) and protein intake (HR 3.21, 95% CI 1.76-5.86), were identified as independently associated with pressure injury development. Higher Braden scores were identified as a protective factor (HR 0.65, 95% CI 0.56-0.77).

CONCLUSIONS

These results indicate that the time to pressure injury development in the group of patients who did not achieve nutritional goals was shorter compared to those who achieved nutritional goals. Further studies should be conducted to confirm these data and to study the relationships in greater detail.

Value of the urea/creatinine index in isolated urine to estimate severe protein hypercatabolism in ventilated patients

Objective

To study the ability of the urea/creatinine index to identify severe protein catabolism from the isolated urine of critically ventilated patients.

Methods

This was a prospective, observational study. It included 52 patients without kidney failure. Variables: total urinary nitrogen estimated from the urea in 24-hour urine on the second (T1) and fourth days (T2) and urea/creatinine index in isolated urine before 24-hour urine collection.

Results

Severe protein hypercatabolism (estimated total urinary nitrogen > 15g) was present in 14 patients (26.9%) at T1 and in 29 (55.7%) at T2. Eighty-four percent of patients had low nutritional risk by the Nutrition Risk in the Critically Ill score. At T1, the Pearson correlation between the estimated total urinary nitrogen and the urea/creatinine index was 0.272 (p = 0.051), and at T2 it was 0.276 (p = 0.048). The urea/creatinine index at T2 had a tendency to better discriminate severe protein hypercatabolism than Acute Physiology and Chronic Health Evaluation II and Nutrition Risk in the Critically Ill (AUC 0.741 versus 0.669 and 0.656, 95%CI: 0.602 - 0.880; 0.519 - 0.818 and 0.506 - 0.806, respectively). The optimal cutoff value of the urea/creatinine index for the diagnosis of severe protein hypercatabolism was 16.15, with a sensitivity of 79.31% (95%CI: 59.74 - 91.29), specificity of 60.87% (95%CI: 38.78 - 79.53), positive predictive value 71.88% (95%CI: 53.02 - 85.60), negative predictive value 70.0% (95%CI: 45.67 - 87.18), LR (+) 2.03 (95%CI: 1.18 - 3.49), and LR (-) 0.34 (95%CI: 0.16 - 0.74).

Conclusion

The urea/creatinine index measured on the fourth day has a certain ability to estimate severe protein hypercatabolism (as defined by estimated total urinary nitrogen) but does not replace total urinary nitrogen in critically ventilated patients without kidney failure. Due to its reasonable sensitivity, it could be used as a screen to identify which patients to take a 24-hour urine sample from.

Risk factors for protein-caloric inadequacy in patients in an intensive care unit

OBJECTIVE

To evaluate the risk factors for protein-caloric inadequacy in critically ill patients.

METHODS

Prospective cohort study of patients hospitalized in an adult intensive care unit between February and November 2017. Patients were followed for 7 days. The conditional probability of inadequacy was calculated using the Kaplan-Meier method and the 95% log-rank test. To assess the risk of inadequacy, crude and adjusted hazard ratios (HR) were calculated using Cox regression with a 95% confidence interval.

RESULTS

Of the 130 patients, 63.8% were male, 73.8% were <60 years of age, and 49.2% were diagnosed with trauma. The mean APACHE II score was 24 points, and 70.0% of the patients had a protein-caloric adequacy >80%. In the univariate analysis, the significant variables for inadequacy were use of vasoactive drugs, interruptions of diet and failure to initiate nutrition early. In the final model, patients who presented with vomiting/gastric residue (adjusted HR = 22.5; 95%CI 5.14 - 98.87) and fasting for extubation (adjusted HR = 14.75; 95%CI 3.59 - 60.63) and for examinations and interventions (adjusted HR = 12.46; 95%CI 4.52 - 34.36) had a higher risk of not achieving protein-caloric adequacy.

CONCLUSION

Achievement of nutritional goals > 80.0% occurred in 70.0% of patients. The risk factors for protein-caloric inadequacy were nutritional interruptions, especially due to vomiting/gastric residue and fasting for extubation, exams and surgical procedures.

Impact of protein intake and nutritional status on the clinical outcome of critically ill patients

OBJECTIVE

To evaluate the association of nutritional status and protein intake with the clinical outcomes of critically ill patients receiving enteral nutrition therapy in an intensive care unit.

METHODS

A retrospective observational analytical study was performed by collecting secondary data recorded in medical records of patients ≥ 18 years of age who were admitted to the intensive care unit and who received exclusive enteral nutrition therapy for at least 72 hours in 2017. Nutritional status was assessed by body mass index and arm circumference. For the estimation of protein requirements, the recommendation of the American Society for Parenteral and Enteral Nutrition was considered. Nutritional adequacy was assessed by the daily collection of prescribed and administered enteral formula. In the analyses, parametric and nonparametric tests were used, and significance was set at p <0.05.

RESULTS

Of the 188 patients evaluated, 71.3% were male. The median age of the patients was 48.5 years (31.0 - 63.75). The main clinical diagnosis was trauma (46.3%), and eutrophic was the most frequent nutritional status (54.8% according to body mass index and 46.4% according to arm circumference). Protein adequacy was not attained in 56.4% of patients, and only 46.8% reached the minimum protein recommendation. The occurrence of mortality was associated with nutritional diagnosis, body mass index (p = 0.023), arm circumference (p = 0.041) and protein adequacy (p = 0.012).

CONCLUSION

Nutritional status and protein intake were significantly associated with the clinical outcomes of critically ill patients.

Effect of Protein-Fortified Diet on Nitrogen Balance in Critically Ill Patients: Results from the OPINiB Trial

Nitrogen balance (NB) is considered a good marker of adequate protein intake and it has been suggested to be a good predictor of patients' health outcomes. However, in literature, there is a lack of large randomized trials examining NB-guided protein intake in patients in intensive care units (ICUs). A randomized controlled trial enrolling patients admitted to ICU was done to compare changes in NB. Participants were randomized to a standard or protein-fortified diet (protein intake of 1.8 g/kg/day according to the guidelines of the Society of Critical Care Medicine and the American Society for Parenteral and Enteral Nutrition). The primary endpoint was represented by the NB on Day 1, 3, and study exit. Forty patients were enrolled in the study (19 in the protein-fortified group). The longitudinal analysis showed that, on Day 3, patients randomized to the protein-fortified diet were more likely (p < 0.001) to present better NB (at 3 days, patients in the protein-fortified diet were estimated to have a nitrate value of 5.22 g more than patients in the standard diet, 95% CI 3.86-6.58). The protein-fortified diet was found to be significantly and directly associated with changes in NB in critically ill patients admitted to ICU.

Safety and efficacy of volume-based feeding in critically ill, mechanically ventilated adults using the 'Protein & Energy Requirements Fed for Every Critically ill patient every Time' (PERFECT) protocol: a before-and-after study

BACKGROUND

Underfeeding in critical illness is common and associated with poor outcomes. According to large prospective hospital studies, volume-based feeding (VBF) safely and effectively improves energy and protein delivery to critically ill patients compared to traditional rate-based feeding (RBF) and might improve patient outcomes. A before-and-after study was designed to evaluate the safety, efficacy and clinical outcomes associated with VBF compared to RBF in a single intensive care unit (ICU).

METHODS

The sample included consecutively admitted critically ill adults, mechanically ventilated for at least 72 h and fed enterally for a minimum of 48 h. The first cohort (n = 46) was fed using RBF, the second (n = 46) using VBF, and observed for 7 days, or until extubation or death. Statistical comparison of percentage feed volume, energy and protein delivered, plus indices of feed intolerance, were the primary outcomes of interest. Secondary observations included ventilation period, mortality, and length of ICU stay (LOICUS).

RESULTS

Groups were comparable in baseline clinical and demographic characteristics and nutrition practices. Volume delivered to the VBF group increased significantly by 11.2% (p ≤ 0.001), energy by 13.4% (p ≤ 0.001) and protein by 8.4% (p = 0.02), compared to the RBF group. In the VBF group, patients meeting > 90% of energy requirements increased significantly from 47.8 to 84.8% (p ≤ 0.001); those meeting > 90% of protein requirements changed from 56.5 to 73.9% (p = 0.134). VBF did not increase symptoms of feed intolerance. Adjusted binomial logistic regression found each additional 1% of prescribed feed delivered decreased the odds of vomiting by 0.942 (5.8%), 95% CI [0.900-0.985], p = 0.010. No differences in mortality or LOICUS were identified. Kaplan-Meier found a significantly increased extubation rate in patients receiving > 90% of protein requirements compared to those meeting < 80%, (p = 0.006). Adjusted Cox regression found the daily probability of being extubated tripled in patients receiving > 90% of their protein needs compared to the group receiving < 80%, hazard ratio 3.473, p = 0.021, 95% CI [1.205-10.014].

CONCLUSION

VBF safely and effectively increased the delivery of energy and protein to critically ill patients. Increased protein delivery may improve extubation rate which has positive patient-centred and financial implications, warranting larger confirmatory trials. This investigation adds weight to the ICU literature supporting VBF, and the growing evidence which advocates for enhanced protein delivery to improve patient outcomes.

Combination of APACHE Scoring Systems with Adductor Pollicis Muscle Thickness for the Prediction of Mortality in Patients Who Spend More Than One Day in the Intensive Care Unit

Background

The objective of the present study was to compare the ability of Acute Physiology and Chronic Health Evaluation (APACHE) scoring systems with the combination of an anthropometric variable score “adductor pollicis muscle (APM) thickness” to the APACHE systems in predicting mortality in the intensive care unit.

Methods

A prospective observational study was conducted with the APM thickness in the dominant hand, and APACHE II and III scores were measured for each patient upon admission. Given scores for the APM thickness were added to APACHE score systems to make two composite scores of APACHE II-APM and APACHE III-APM. The accuracy of the two composite models and APACHE II and III systems in predicting mortality of patients was compared using the area under the ROC curve.

Results

Three hundred and four patients with the mean age of 54.75 ± 18.28 years were studied, of which 96 (31.57%) patients died. Median (interquartile range) of APACHE II and III scores was 15 (12–20) and 47 (33–66), respectively. Median (interquartile range) of APM thickness was 15 (12–17) mm, respectively. The area under the ROC curves for the prediction of mortality was 0.771 (95% CI: 0.715–0.827), 0.802 (95% CI: 0.751–0.854), 0.851 (95% CI: 0.807–0.896), and 0.865 (95% CI: 0.822–0.908) for APACHE II, APACHE III, APACHE II-APM, and APACHE III-APM, respectively.

Conclusion

Although improvements in the area under ROC curves were not statistically significant when the APM thickness added to the APACHE systems, but the numerical value added to AUCs are considerable.

Effect of hypocaloric normoprotein or trophic feeding versus target full enteral feeding on patient outcomes in critically ill adults: a systematic review

Uncertainty surrounds the optimal approach to feeding the critically ill, with increasing interest in the concept of intentional underfeeding to reduce metabolic stress while maintaining gut integrity. Conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, this systematic review evaluates clinical outcomes reported in studies comparing hypocaloric normonitrogenous or trophic feeding (collectively 'intentional underfeeding') targeted full energy feeding administered via enteral nutrition to adult critically ill patients. Electronic databases including PubMed, CINAHL, EMBASE and CENTRAL were searched up to September 2017 for trials evaluating intentional underfeeding versus targeted energy feeding interventions on clinical outcomes (mortality, length of stay, duration of ventilation, infective complications, feeding intolerance and glycaemic control) among critically ill adult patients. Bias of included studies was assessed using the Cochrane risk of bias tool. Of the 595 articles identified, seven studies (six randomised controlled trials, one non-randomised trial) met the inclusion criteria, representing 2,684 patients (hypocaloric normonitrogenous n=668; trophic n=681; full energy feeding n=1335). Across the studies, there was considerable heterogeneity in study methodology, population, feeding strategy and outcomes and their timepoints. We observed no evidence that intentional underfeeding, when compared to targeting full energy feeding, reduced mortality or duration of ventilation or length of stay. However, limited trial evidence is available on the impact of intentional underfeeding on post-discharge functional and quality of life outcomes.

Energy, Protein, Carbohydrate, and Lipid Intakes and Their Effects on Morbidity and Mortality in Critically Ill Adult Patients: A Systematic Review

The guidelines for nutritional support in critically ill adult patients differ in various aspects. The optimal amount of energy and nutritional substrates supplied is important for reducing morbidity and mortality, but unfortunately this is not well known, because the topic is complex and every patient is individual. The aim of this review was to gather recent pertinent information concerning the nutritional support of critically ill patients in the intensive care unit (ICU) with respect to the energy, protein, carbohydrate, and lipid intakes and the effect of their specific utilization on morbidity and mortality. Enteral nutrition (EN) is generally recommended over parenteral nutrition (PN) and is beneficial when administered within 24-48 h after ICU admission. In contrast, early PN does not provide substantial advantages in terms of morbidity and mortality, and the time when it is safe and beneficial remains unclear. The most advantageous recommendation seems to be administration of a hypocaloric (<20 kcal · kg^-1 · d^-1), high-protein diet (amino acids at doses of ≥2 g · kg^-1 · d^-1), at least during the first week of critical illness. Another important factor for reducing morbidity is the maintenance of blood glucose concentrations at 120-150 mg/dL, which is accomplished with the use of insulin and lower doses of glucose of 1-2 g · kg^-1 · d^-1, because this prevents the risk of hypoglycemia and is associated with a better prognosis according to recent studies. A fat emulsion is used as a source of required calories because of insulin resistance in the majority of patients. In addition, lipid oxidation in these patients is ∼25% higher than in healthy subjects.

Optimizing Protein Intake and Nitrogen Balance (OPINiB) in Adult Critically Ill Patients: A Study Protocol for a Randomized Controlled Trial

BACKGROUND

Adequate nutrition of critically ill patients plays a key role in the modulation of metabolic response to stress.

OBJECTIVE

This paper presents the development of a protocol for a randomized controlled trial (RCT) aimed at comparing clinical outcomes of patients in the intensive care unit (ICU) administered with standard and protein-fortified diet. Together with the RCT study protocol, the results of the observational analysis conducted to assess the feasibility of the RCT are presented.

METHODS

An RCT on adult patients admitted to ICU and undergoing mechanical ventilation in the absence of renal or hepatic failure will be conducted. Patients enrolled will be randomized with an allocation rate of 1:1 at standard diet versus protein-fortified diet. The estimated sample size is 19 per arm, for a total of 38 patients to be randomized.

RESULTS

Enrollment began in January 2017. In the feasibility study, 14 patients were enrolled. Protein administration increased significantly (P<.001) over time but was significantly lower compared to that recommended (P<.001). Blood urea nitrogen significantly increased (P<.03) over the period of observation. Such increased catabolism resulted in negative cumulative nitrogen balance (NB) in all patients, and some patients presented with a more negative NB compared to the others.

CONCLUSIONS

Results of the feasibility study clearly confirmed that protein provision in ICU patients is below that recommended and that this results in impaired NB. The emerging of an interindividual variability in NB will be further analyzed in the RCT.

TRIAL REGISTRATION

ClinicalTrials.gov NCT02990065; https://clinicaltrials.gov/ct2/show/NCT02990065 (Archived by WebCite at http://www.webcitation.org/6prsqZdRM).

Nutritional considerations during prolonged exposure to a confined, hyperbaric, hyperoxic environment: recommendations for saturation divers

Saturation diving is an occupation that involves prolonged exposure to a confined, hyperoxic, hyperbaric environment. The unique and extreme environment is thought to result in disruption to physiological and metabolic homeostasis, which may impact human health and performance. Appropriate nutritional intake has the potential to alleviate and/or support many of these physiological and metabolic concerns, whilst enhancing health and performance in saturation divers. Therefore, the purpose of this review is to identify the physiological and practical challenges of saturation diving and consequently provide evidence-based nutritional recommendations for saturation divers to promote health and performance within this challenging environment. Saturation diving has a high-energy demand, with an energy intake of between 44 and 52 kcal/kg body mass per day recommended, dependent on intensity and duration of underwater activity. The macronutrient composition of dietary intake is in accordance with the current Institute of Medicine guidelines at 45-65 % and 20-35 % of total energy intake for carbohydrate and fat intake, respectively. A minimum daily protein intake of 1.3 g/kg body mass is recommended to facilitate body composition maintenance. Macronutrient intake between individuals should, however, be dictated by personal preference to support the attainment of an energy balance. A varied diet high in fruit and vegetables is highly recommended for the provision of sufficient micronutrients to support physiological processes, such as vitamin B12 and folate intake to facilitate red blood cell production. Antioxidants, such as vitamin C and E, are also recommended to reduce oxidised molecules, e.g. free radicals, whilst selenium and zinc intake may be beneficial to reinforce endogenous antioxidant reserves. In addition, tailored hydration and carbohydrate fueling strategies for underwater work are also advised.

Cilostazol administration with combination enteral and parenteral nutrition therapy remarkably improves outcome after subarachnoid hemorrhage

OBJECTIVE

In order to prevent cerebral vasospasm (VS) following aneurysmal subarachnoid hemorrhage (SAH), we introduced combined enteral nutrition (EN) and parenteral nutrition (PN) with oral cilostazol administration to the postoperative patient after SAH and investigated the effect on VS.

METHODS

After aneurysmal SAH, 130 postoperative patients were enrolled in this study between April 2008 and March 2012. The patients enrolled before April 2010 were treated by conventional therapy (control group). The patients enrolled after April 2010 were administrated cilostazol 200 mg/day and received EN and PN simultaneously (combined group).

RESULTS

The combined group consisted of 62 patients and the control group of 68 patients. Angiographic VS occurred in 33.9 % (n = 21) of the combined group and in 51.5 % (n = 35) of the control group (p = 0.051, Fisher exact test). The incidence of symptomatic VS was significantly lower in the combined group (p = 0.001). The incidence of new cerebral infarctions was also significantly lower in the combined group (p = 0.0006). Clinical outcome at discharge was also significantly better in the combined group than in control group (p = 0.031).

CONCLUSIONS

Cilostazol administration with combination EN and PN is remarkably effective in preventing cerebral VS after aneurysmal SAH.