Can Nutritional Assessment Tools Predict Response to Nutritional Therapy?

A Novel Machine-Learning Algorithm to Predict the Early Termination of Nutrition Support Team Follow-Up in Hospitalized Adults: A Retrospective Cohort Study

BACKGROUND

For hospitalized adults, it is important to initiate the early reintroduction of oral food in accordance with nutrition support team guidelines. The aim of this study was to develop and validate a machine learning-based algorithm that predicts the early termination of medical nutritional therapy (the transition to oral feeding).

METHODS

This retrospective cohort study included consecutive adult patients admitted to the Hacettepe hospital (from 1 January 2018 to 31 December 2022). The outcome of the study was the prediction of an early transition to adequate oral feeding before discharge. The dataset was randomly (70/30) divided into training and test datasets. We used six ML algorithms with multiple features to construct prediction models. ML model performance was measured according to the accuracy, area under the receiver operating characteristic curve, and F1 score. We used the Boruta Method to determine the important features and interpret the selected features.

RESULTS

A total of 2298 adult inpatients who were followed by a nutrition support team for medical nutritional therapy were included. Patients received parenteral nutrition (1471/2298, 64.01%), enteral nutrition (717/2298, 31.2%), or supplemental parenteral nutrition (110/2298, 4.79%). The median (interquartile range) Nutritional Risk Screening (NRS-2002) score was 5 (1). Six prediction algorithms were used, and the artificial neural network and elastic net models achieved the greatest area under the ROC in all outcomes (AUC = 0.770). Ranked by z-value, the 10 most important features in predicting an early transition to oral feeding in the artificial neural network and elastic net algorithms were parenteral nutrition, surgical wards, surgical outcomes, enteral nutrition, age, supplemental parenteral nutrition, digestive system diseases, gastrointestinal complications, NRS-2002, and impaired consciousness.

CONCLUSIONS

We developed machine learning models for the prediction of an early transition to oral feeding before discharge. Overall, there was no discernible superiority among the models. Nevertheless, the artificial neural network and elastic net methods provided the highest AUC values. Since the machine learning model is interpretable, it can enable clinicians to better comprehend the features underlying the outcomes. Our study could support personalized treatment and nutritional follow-up strategies in clinical decision making for the prediction of an early transition to oral feeding in hospitalized adult patients.

ESPEN practical guideline: Nutritional support for polymorbid medical inpatients

BACKGROUND

Disease-related malnutrition in polymorbid medical inpatients is a highly prevalent syndrome associated with significantly increased morbidity, disability, short- and long-term mortality, impaired recovery from illness, and healthcare costs.

AIM

As there are uncertainties in applying disease-specific guidelines to patients with multiple conditions, our aim was to provide evidence-based recommendations on nutritional support for the polymorbid patient population hospitalized in medical wards.

METHODS

The 2023 update adheres to the standard operating procedures for ESPEN guidelines. We undertook a systematic literature search for 15 clinical questions in three different databases (Medline, Embase and the Cochrane Library), as well as in secondary sources (e.g., published guidelines), until July 12th, 2022. Retrieved abstracts were screened to identify relevant studies that were used to develop recommendations (including SIGN grading), which was followed by submission to Delphi voting. Here, the practical version of the guideline is presented which has been shortened and equipped with flow charts for patients care.

RESULTS

32 recommendations (7× A, 11× B, 10× O and 4× GPP), which encompass different aspects of nutritional support were included from the scientific guideline including indication, route of feeding, energy and protein requirements, micronutrient requirements, disease-specific nutrients, timing, monitoring and procedure of intervention. Here, the practical version of the guideline is presented which has been shortened and equipped with flow charts for patients care.

CONCLUSIONS

Recent high-quality trials have provided increasing evidence that nutritional support can reduce morbidity and other complications associated with malnutrition in polymorbid patients. The timely screening of patients for risk of malnutrition at hospital admission followed by individualized nutritional support interventions for at-risk patients should be part of routine clinical care and multimodal treatment in hospitals worldwide. Use of this updated practical guideline offers an evidence-based nutritional approach to polymorbid medical inpatients and may improve their outcomes.

ESPEN guideline on nutritional support for polymorbid medical inpatients

BACKGROUND

Disease-related malnutrition in polymorbid medical inpatients is a highly prevalent syndrome associated with significantly increased morbidity, disability, short- and long-term mortality, impaired recovery from illness, and cost of care.

AIM

As there are uncertainties in applying disease-specific guidelines to patients with multiple conditions, our aim was to provide evidence-based recommendations on nutritional support for the polymorbid patient population hospitalized in medical wards.

METHODS

This update adheres to the standard operating procedures for ESPEN guidelines. We did a systematic literature search for 15 clinical questions in three different databases (Medline, Embase and the Cochrane Library), as well as in secondary sources (e.g. published guidelines), until July 12th. Retrieved abstracts were screened to identify relevant studies that were used to develop recommendations (incl. SIGN grading), which was followed by submission to Delphi voting.

RESULTS

From a total of 3527 retrieved abstracts, 60 new relevant studies were analyzed and used to generate a guideline draft that proposed 32 recommendations (7x A, 11x B, 10x O and 4x GPP), which encompass different aspects of nutritional support including indication, route of feeding, energy and protein requirements, micronutrient requirements, disease-specific nutrients, timing, monitoring and procedure of intervention. The results of the first online voting showed a strong consensus (agreement of >90%) on 100% of the recommendations. Therefore, no final consensus conference was needed.

CONCLUSIONS

Recent high-quality trials have provided increasing evidence that nutritional support can reduce morbidity and other complications associated with malnutrition in polymorbid patients. The timely screening of patients for risk of malnutrition at hospital admission followed by individualized nutritional support interventions for at-risk patients should be part of routine clinical care and multimodal treatment in hospitals worldwide. Use of this updated guideline offers an evidence-based nutritional approach to the polymorbid medical inpatients and may improve their outcomes.

The Use of the Perioperative Nutrition Score in Postoperative Pediatric Inflammatory Bowel Disease Patients

BACKGROUND AND OBJECTIVES

Preoperative malnutrition is associated with increased postoperative morbidity. The perioperative nutrition score (PONS) was developed to identify patients at risk of malnutrition. We sought to assess the correlation between preoperative PONS and postoperative outcomes in pediatric inflammatory bowel disease (IBD) patients.

METHODS

We performed a retrospective cohort study of IBD patients, less than 21 years of age, who underwent elective bowel resection between June 2018 and November 2021. Patients were divided based upon whether they met PONS criteria. The primary outcome was postoperative surgical site infections.

RESULTS

96 patients were included. Sixty-one patients (64%) met at least one PONS criteria, while 35 patients (36%) met none. PONS positive patients more frequently received preoperative TPN supplementation (p < .001). There was no difference in preoperative oral nutritional supplementation between groups. Patients that screened positive for PONS had a longer hospital stay (p = .002), more readmissions (p = .029), and more surgical site infections (p = .002).

CONCLUSIONS

Our data highlight the prevalence of malnutrition in the pediatric IBD population. Patients who screened positive had worse postoperative outcomes. Further, very few of these patients received preoperative optimization with oral nutritional supplementation. There is a need for standardization of nutritional evaluation to improve preoperative nutritional status and postoperative outcomes.

LEVEL OF EVIDENCE

III.

TYPE OF STUDY

Retrospective Cohort.

Association of nutrition risk screening 2002 and Malnutrition Universal Screening Tool with COVID-19 severity in hospitalized patients in Iran

Background: Malnutrition affects normal body function and is associated with disease severity and mortality. Due to the high prevalence of malnutrition reported in patients with coronavirus disease 2019 (COVID-19), the current study examined the association between malnutrition and disease severity in hospitalized adult patients with COVID-19 in Iran.Methods: In this prospective observational study, 203 adult patients with COVID-19 verified by real-time polymerase chain reaction test and chest computed tomography were recruited from those admitted to a university hospital in Iran. To determine COVID-19 intensity, patients were categorized into four groups. Malnutrition assessment was based on the Malnutrition Universal Screening Tool (MUST) and nutrition risk screening score (NRS-2002). An ordinal regression model was run to assess the association between malnutrition and disease severity.Results: In the studies sample of Iranian patients with COVID-19, 38.3% of patients had severe COVID-19. According to NRS-2002, 12.9% of patients were malnourished. Based on MUST, 2% of patients were at medium, and 13.4% of patients were at high risk of malnutrition. Malnutrition was associated with a higher odds of extremely severe COVID-19 according to NRS-2002 (odds ratio, 1.38; 95% confidence interval, 0.21–2.56; P=0.021).Conclusions: Malnutrition was not prevalent in the studies sample of Iranian patients with COVID-19; however, it was associated with a higher odds of extremely severe COVID-19.

Tailoring nutrition therapy amid the COVID-19 pandemic: Does it work?

Background

The COVID-19 pandemic has been a challenge for nutrition monitoring and delivery. This study evaluates clinical and nutritional characteristics of patients infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and investigates the relationship between nutrition delivery and clinical outcomes.

Methods

Prospective observational study of adults admitted for >24 hrs to a tertiary-care hospital during a period of 2months. Data was collected on disease severity, energy, protein delivery and adequacy, use of mechanical ventilation (MV), hospital length of stay (LOS). Multivariate logistic regression models were used to determine the associations with mortality as the primary outcome.

Results

1083 patients: 69% male (n = 747), 31% females (n = 336), mean age 58.2 ± 12.8 with 26.6 ± 4.32 BMI were analysed. 1021 patients survived and 62 deaths occurred, with 183 and 900 patients in the ICU and ward, respectively. Inadequate calorie and protein delivery had significantly higher mortality than those with adequate provision (p < 0.001) among the ICU patients. In bivariate logistic regression analysis, inadequacy of energy and protein, disease severity, comorbidities ≥3, NRS score ≥3 and prone ventilation correlates with mortality (p < 0.001). In multivariate logistic regression analysis of the ICU patients, energy inadequacy (OR:3.6, 95%CI:1.25–10.2) and prone ventilation (OR:11.0, 95%CI:3.8–31.9) were significantly (p < 0.05) associated with mortality after adjusting for disease severity, comorbidities and MV days.

Conclusion

Most patients infected with SARS-CoV-2 are at nutrition risk that can impact outcome. Our data suggest that addressing nutritional adequacy can be one of the measures to reduce hospital LOS, and mortality among nutritionally risk patients.

Association between nutrition delivery, modified Nutrition Risk in Critically Ill score, and 28-day mortality

BACKGROUND

Nutrition delivery, is a key component in the management of critical illness. Traditional scoring systems are inadequate in the intensive care unit (ICU), as patients are sedated. Our study examines the associations between calorie and protein adequacy, 28-day mortality, and modified Nutrition Risk in Critically Ill (mNUTRIC) score and identify at-risk ICU patients who may benefit more from nutrition intervention.

METHODS

Prospective observational study of adults admitted for >24h to the ICU of a tertiary care hospital during a period of 7 months. Data were collected on nutrition delivery, mNUTRIC score, use of mechanical ventilation, and ICU/hospital length of stay (LOS). Multivariate logistic regression analysis was done with 28-day mortality as the primary outcome.

RESULTS

Two hundred forty-eight patients were recruited for the study with 60% male, 40% female, mean age 60.8 ± 14.7, and body mass index of 24.2 ± 4.8. Patients with inadequate calorie and protein delivery had significantly higher 28-day mortality than those with adequate provision (P=.032 and P =. 017). In bivariate logistic regression analysis, mNUTRIC score (odds ratio [OR], 1.802; 95% CI, 1.042-3.117; P = .035) and adequacy of energy (OR, 1.92) and protein (OR, 2.49) correlate with 28-day mortality. The Kaplan-Meier survival curve showed a survival benefit in the ≥80% energy and protein group among the total patients and was also significantly associated with lower hospital and ICU LOS, even after matching (log-rank test, P < 0.001).

CONCLUSION

Adequacy of energy and protein to ≥80% may shorten ICU/hospital LOS and reduce 28-day mortality among both high and low nutrition risk patients.

Translation and adaptation of the modified NUTRIC score for critically ill patients

BACKGROUND & AIMS

Some critically ill patients are at high nutritional risk, and early identification of these patients is needed to reduce morbidity and mortality related to underfeeding. The Modified NUTrition Risk in Critically ill (mNUTRIC) score is the first nutritional risk assessment tool developed and validated specifically for ICU patients. This study aims to translate and adapt the Modified NUTRIC (mNUTRIC) Score into Persian to facilitate use in Iranian Intensive Care Units and assess its efficiency in a pilot sample.

METHOD

The translation process followed standardized steps: initial translation, synthesis of translations, back -translation to the English language, revision and cultural adaptation of the tool by language specialist and expert committee. A pilot study was conducted on the application of the tool in 46 critically ill patients from three ICUs in Iran hospitals.

RESULTS

The translation and adaptation process generated a feasible version of the mNUTRIC Score in the Persian language.The translated version was easily introduced into Iranian ICUs. The prevalence of patients with a mNUTRIC score of five or more was 43% (n = 46).

CONCLUSION

Translation of mNUTRIC Score from English into Persian, following internationally accepted methodology, has provided the ICU care in Iran with a comprehensive and useful instrument.

Nutritional risk screening score as an independent predictor of nonventilator hospital-acquired pneumonia: a cohort study of 67,280 patients

BACKGROUND

Currently, the association of nutritional risk screening score with the development of nonventilator hospital-acquired pneumonia (NV-HAP) is unknown. This study investigated whether nutritional risk screening score is an independent predictor of NV-HAP.

METHODS

This retrospective cohort study was conducted between September 2017 and June 2020 in a tertiary hospital in China. The tool of Nutritional Risk Screening 2002 (NRS-2002) was used for nutritional risk screening. A total score of ≥3 indicated a patient was "at nutritional risk." Logistic regression was applied to explore the association between the NRS score and NV-HAP.

RESULTS

A total of 67,280 unique patients were included in the study. The incidence of NV-HAP in the cohort for the NRS < 3 and ≥ 3 NRS group was 0.4% (232/62702) and 2.6% (121/4578), respectively. In a multivariable logistic regression model adjusted for all of the covariates, per 1-point increase in the NRS score was associated with a 30% higher risk of NV-HAP (OR = 1.30; 95%CI:1.19-1.43). Similarly, patients with NRS score ≥ 3 had a higher risk of NV-HAP with an odds ratio (OR) of 2.06 (confidence interval (CI): 1.58-2.70) than those with NRS score < 3. Subgroup analyses indicated that the association between the NRS score and the risk of NV-HAP was similar for most strata. Furthermore, the interaction analyses revealed no interactive role in the association between NRS score and NV-HAP.

CONCLUSION

NRS score is an independent predictor of NV-HAP, irrespective of the patient's characteristics. NRS-2002 has the potential as a convenient tool for risk stratification of adult hospitalized patients with different NV-HAP risks.

Use of Nutrition Risk in Critically Ill (NUTRIC) Scoring System for Nutrition Risk Assessment and Prognosis Prediction in Critically Ill Neurological Patients: A Prospective Observational Study

BACKGROUND

Critically ill patients who are hospitalized in a neurological intensive care unit (NICU) are largely susceptible to nutrition risk. However, only a limited number of studies have investigated the applicable assessment tool in NICUs.

METHODS

This was a prospective observational study conducted at a single-center NICU. A total of 140 adult patients who were hospitalized for >24 hours were enrolled. The Nutritional Risk Screening 2002, Nutrition Risk in the Critically ill (NUTRIC), and modified NUTRIC (mNUTRIC) scores were applied for the assessment of nutrition risk. Analyses of multivariable logistic regression were performed by considering a 28-day mortality as the outcome of interest.

RESULTS

Nutrition risk was commonly identified in NICU patients. Multivariate analysis revealed that age ≥60 years, hospital infection, mechanical ventilation, and high nutrition risk (mNUTRIC score ≥ 5) independently increased 28-day mortality in NICU patients. For subgroups of patients with a prolonged length of stay, high nutrition risk (mNUTRIC score ≥ 5) has always been an independent risk factor of 28-day mortality. Both NUTRIC and mNUTRIC scores were able to predict 28-day mortality, with area under the receiver operating characteristic curves of 0.857 (95% CI, 0.786-0.928) and 0.856 (95% CI, 0.786-0.927), respectively.

CONCLUSION

The mNUTRIC scoring system is not only a useful tool for nutrition risk assessment but also, and more importantly, it is independently related to the risk of 28-day mortality in NICU patients. Therefore, mNUTRIC scoring is an appropriate tool for nutrition risk assessment and prognosis prediction of NICU patients.

High nutritional risk is associated with unfavorable outcomes in patients admitted to an intensive care unit

OBJECTIVE

To evaluate possible associations between nutritional risk and the clinical outcomes of critical patients admitted to an intensive care unit.

METHODS

A prospective study was carried out with a cohort comprising 200 patients admitted to a university hospital intensive care unit. Nutritional risk was assessed with the NRS-2002 and NUTRIC scores. Patients with scores ≥ 5 were considered at high nutritional risk. Clinical data and outcome measures were obtained from patients' medical records. Multiple logistic regression analysis was used to calculate odds ratios and their respective 95% confidence intervals (for clinical outcomes).

RESULTS

This sample of critical patients had a mean age of 59.4 ± 16.5 years and 53.5% were female. The proportions at high nutritional risk according to NRS-2002 and NUTRIC were 55% and 36.5%, respectively. Multiple logistic regression models adjusted for gender and type of admission indicated that high nutritional risk assessed by the NRS-2002 was positively associated with use of mechanical ventilation (OR = 2.34; 95%CI 1.31 - 4.19; p = 0.004); presence of infection (OR = 2.21; 95%CI 1.24 - 3.94; p = 0.007), and death (OR = 1.86; 95%CI 1.01 - 3.41; p = 0.045). When evaluated by NUTRIC, nutritional risk was associated with renal replacement therapy (OR = 2.10; 95%CI 1.02 - 4.15; p = 0.040) and death (OR = 3.48; 95%CI 1.88 - 6.44; p < 0.001).

CONCLUSION

In critically ill patients, high nutritional risk was positively associated with an increased risk of clinical outcomes including hospital death.

Measuring and monitoring lean body mass in critical illness

PURPOSE OF REVIEW

To help guide metabolic support in critical care, an understanding of patients' nutritional status and risk is important. Several methods to monitor lean body mass are increasingly used in the ICU and knowledge about their advantages and limitations is essential.

RECENT FINDINGS

Computed tomography scan analysis, musculoskeletal ultrasound, and bioelectrical impedance analysis are emerging as powerful clinical tools to monitor lean body mass during ICU stay. Accuracy, expertise, ease of use at the bedside, and costs are important factors which play a role in determining which method is most suitable. Exciting new research provides an insight into not only quantitative measurements, but also qualitative measurements of lean body mass, such as infiltration of adipose tissue and intramuscular glycogen storage.

SUMMARY

Methods to monitor lean body mass in the ICU are under constant development, improving upon bedside usability and offering new modalities to measure. This provides clinicians with valuable markers with which to identify patients at high nutritional risk and to evaluate metabolic support during critical illness.

Are all low-NUTRIC-score patients the same? Analysis of a multi-center observational study to determine the relationship between nutrition intake and outcome

BACKGROUND

The NUTrition Risk in the Critically Ill (NUTRIC) scoring system is a tool useful, discriminating critically-ill patients benefiting from optimal nutrition intake (>80% of prescription). Recent recommendations advocate for withholding artificial nutrition among low-NUTRIC patients, however, we hypothesized that some low-NUTRIC patients would show an association between nutrition intake and outcome.

METHODS

Patients were selected from the 2013-2014 International Nutrition Surveys when ICU length of stay (LICU) ≥72 h, baseline mNUTRIC score ≤4 and had at least three evaluable nutrition days (N = 2781). Proportion of prescription received during evaluable days was associated to 60-day hospital mortality by a logistic regression modelling. A priori, we expected that the association between proportion of prescription received and mortality might differ according to: LICU, BMI and prior unintentional weight loss or reduced oral intake.

RESULTS

A total of 2781 patients fulfilled the inclusion criteria and participated in the study. Ten percent of the sample had a BMI <20 kg/m² and 20% experienced either unintentional weight loss during the last 3 months, or reduced food intake over the last week. Sixty-day hospital mortality was 15% and median LICU reached 11.3 [6.3-21.7] days. Mean total prescription received by any means of nutritional support during the first 12 evaluable days was 57.4 ± 28.1% for energy and 53.7 ± 29.2% for protein. In the pooled, subgroup and sensitivity analyses, no significant associations were identified.

CONCLUSION

Low-NUTRIC (≤4) patients demonstrate a prolonged LICU, while experiencing significant mortality and a high prevalence of malnutrition risk factors. Although improvements in mortality were not achieved with increased nutritional intake, this should not be construed as a rationale for withholding artificial nutrition among this patient group.

Determination of Nutrition Risk and Status in Critically Ill Patients: What Are Our Considerations?

The stress catabolism state predisposes critically ill patients to a high risk of malnutrition. This, coupled with inadequate or delayed nutrition provision, will lead to further deterioration of nutrition status. Preexisting malnutrition and iatrogenic underfeeding are associated with increased risk of adverse complications. Therefore, accurate detection of patients who are malnourished and/or with high nutrition risk is important for timely and optimal nutrition intervention. Various tools have been developed for nutrition screening and assessment for hospitalized patients, but not all are studied or validated in critically ill populations. In this review article, we consider the pathophysiology of malnutrition in critical illness and the currently available literature to develop recommendations for nutrition screening and assessment. We suggest the use of the (modified) Nutrition Risk in the Critically Ill (mNUTRIC) for nutrition risk screening and the subjective global assessment (SGA) together with other criteria relevant to the critically ill patients, such as gastrointestinal function, risk of aspiration, determination of sarcopenia and frailty, and risk of refeeding syndrome for nutrition assessment. Further research is needed to identify suitable nutrition monitoring indicators to determine the response to the provision of nutrition.

ESPEN guidelines on nutritional support for polymorbid internal medicine patients

BACKGROUND & AIMS

Polymorbidity (also known as multimorbidity) - defined as the co-occurrence of at least two chronic health conditions - is highly prevalent, particularly in the hospitalized population. Nonetheless, clinical guidelines largely address individual diseases and rarely account for polymorbidity. The aim of this project was to develop guidelines on nutritional support for polymorbid patients hospitalized in medical wards.

METHODS

The methodology used for the development of the current project follows the standard operating procedures for ESPEN guidelines. It started with an initial meeting of the Working Group in January 2015, where twelve key clinical questions were developed that encompassed different aspects of nutritional support: indication, route of feeding, energy and protein requirements, micronutrient requirements, disease-specific nutrients, timing, monitoring and procedure of intervention. Systematic literature searches were conducted in three different databases (Medline, Embase and the Cochrane Library), as well as in secondary sources (e.g. published guidelines), until April 2016. Retrieved abstracts were screened to identify relevant studies that were used to develop recommendations, which were followed by submission to Delphi voting rounds.

RESULTS

From a total of 4532 retrieved abstracts, 38 relevant studies were analyzed and used to generate a guideline draft that proposed 22 recommendations and four statements. The results of the first online voting showed a strong consensus (agreement of >90%) in 68% of recommendations and 75% of statements, and consensus (agreement of >75-90%) in 32% of recommendations and 25% of statements. At the final consensus conference, a consensus greater than 89% was reached for all of the recommendations.

CONCLUSIONS

Despite the methodological difficulties in creating non-disease specific guidelines, the evidence behind several important aspects of nutritional support for polymorbid medical inpatients was reviewed and summarized into practical clinical recommendations. Use of these guidelines offer an evidence-based nutritional approach to the polymorbid medical inpatient and may improve their outcomes.

When Is Parenteral Nutrition Appropriate?

Parenteral nutrition (PN) represents one of the most notable achievements of modern medicine, serving as a therapeutic modality for all age groups across the healthcare continuum. PN offers a life-sustaining option when intestinal failure prevents adequate oral or enteral nutrition. However, providing nutrients by vein is an expensive form of nutrition support, and serious adverse events can occur. In an effort to provide clinical guidance regarding PN therapy, the Board of Directors of the American Society for Parenteral and Enteral Nutrition (ASPEN) convened a task force to develop consensus recommendations regarding appropriate PN use. The recommendations contained in this document aim to delineate appropriate PN use and promote clinical benefits while minimizing the risks associated with the therapy. These consensus recommendations build on previous ASPEN clinical guidelines and consensus recommendations for PN safety. They are intended to guide evidence-based decisions regarding appropriate PN use for organizations and individual professionals, including physicians, nurses, dietitians, pharmacists, and other clinicians involved in providing PN. They not only support decisions related to initiating and managing PN but also serve as a guide for developing quality monitoring tools for PN and for identifying areas for further research. Finally, the recommendations contained within the document are also designed to inform decisions made by additional stakeholders, such as policy makers and third-party payers, by providing current perspectives regarding the use of PN in a variety of healthcare settings.