Applied nutrition in ICU patients. A consensus statement of the American College of Chest Physicians

Early initiation of oral intake on length of hospital stay in postoperative patients admitted to the intensive care unit

Early oral intake is recommended for postoperative recovery. We determined whether early oral intake affects postoperative hospital stay. Using the diagnosis procedure combination system introduced in Japan in 2003, patients were classified into major diagnostic categories (MDC) to determine whether the postoperative start date of oral nutrition reduces the postoperative length of hospital stay. A total of 491 patients (age range,15-94 years; median, 72 years; male = 316; female = 175) were analyzed, or which 341 cases of MDC05 (cardiovascular diseases) and 150 cases of MDC06 (digestive system diseases, liver, biliary, and pancreatic disease) were admitted to the intensive care unit. The patients were divided into 2 groups: the non-elderly group, <65 years old, and the elderly group, ≥65 years old. Multivariate analysis was conducted to identify the factors influencing the length of postoperative hospital stay. Explanatory variables included body mass index (18.5-24.9), geriatric nutritional risk index ≥ 98, C-reactive protein, postoperative start date of enteral nutrition, postoperative start date of oral nutrition, meal intake rate, medical resources, and nutrition and meal guidance. In MDC05 and MDC06, initiating oral intake early postoperatively significantly contributed to reducing the postoperative number of days of hospital stay (MDC05, all; β = 0.256, P < .001, non-elderly; β = 0.440, P < .001, elderly; β = 0.240, P < .001: MDC06, all; β = 0.563, P < .001, non-elderly; β = 0.552, P < .001, elderly; β = 0.528, P < .001). In the non-elderly group of MDC06, a body mass index of 18.5-24.9 influenced the shorter postoperative number of days of hospital stay (β = -0.320, P = .011). Nutritional management to promote early oral intake is crucial for optimizing the duration of hospital stay in postoperative patients admitted to the intensive care unit. This study demonstrated the importance of preadmission nutritional management.

Multidisciplinary nutritional support team and mortality in critically ill patients with acute respiratory distress syndrome

BACKGROUND

A careful approach is required when providing nutritional support to patients with acute respiratory distress syndrome (ARDS). This study investigated whether implementing a multidisciplinary nutritional support team (NST) is associated with improved survival outcomes in patients with ARDS.

METHODS

In a nationwide population-based cohort study, all adult patients admitted to the intensive care unit (ICU) in South Korea with a primary diagnosis of ARDS from January 1, 2017, to December 31, 2021, were included. The NST comprised four professionals (physicians, full-time nurses, full-time pharmacists, and full-time clinical dietitians). Patients admitted to ICUs with and without the NST system were allocated to the NST and non-NST groups, respectively.

RESULTS

The analysis comprised a total of 15,555 patients with ARDS. Among them, 6615 (42.5%) were in the NST group, and 8940 (57.5%) were in the non-NST group. After adjusting for covariates in the multivariable logistic regression, the NST group showed a 19% lower 30-day mortality than the non-NST group (odds ratio: 0.81, 95% confidence interval: 0.75-0.87, p < .001). Furthermore, after adjusting for covariates in multivariable Cox regression, the NST group showed a 12% lower 1-year all-cause mortality than the non-NST group (hazard ratio: 0.88, 95% confidence interval: 0.85-0.92, p < .001).

CONCLUSIONS

NST implementation was associated with enhanced 30-day and 1-year survival rates in patients with ARDS. These findings indicate that nutritional support provided by the NST may influence the survival outcomes of patients with ARDS in the ICU.

Association between energy surplus and intensive care unit length of stay in critically ill patients: A retrospective cohort study

BACKGROUND

Patients experiencing persistent critical illness have poor short-term and long-term outcomes and consume disproportionate amounts of health care resources. Nutrition optimization may improve outcomes, though few data exist on resting energy expenditure and nutrition requirements. We hypothesized that increased energy surplus per day is associated with increased intensive care unit (ICU) length of stay (LoS) in critically ill patients.

METHODS

Patients from a single ICU at Royal London Hospital were included in this retrospective cohort study.

EXPOSURE

energy surplus measured by serial indirect calorimetry (IC) and nutrition intake.

INCLUSION CRITERIA

mechanical ventilation of ≥3 days and expected to remain ventilated.

PRIMARY OUTCOME

ICU LoS.

RESULTS

Across 30 patients (median LoS 21 days), increased ICU LoS was associated with actual daily energy intake surplus to resting energy expenditure (REE) (R2 0.16; P < 0.005). Median REE was less than predicted energy requirements: 24 kcal per day per kilogram of ideal body weight (IBW) (interquartile range [IQR], 20-28) vs 28 kcal/day/kg IBW (IQR, 26-29) (P < 0.001). Patients with COVID-19 had a median energy surplus (actual intake- REE) + 344 kcal/day (IQR 35-517) vs -57 kcal/day (IQR -324 to 211) in other patients (P = 0.011); however, they had a median LoS of 44 days (IQR 26-58) vs 10 days (IQR 7-24), respectively (P < 0.001). Patients with obesity had a median energy deficit of -32 kcal/day (IQR -384 to 335) vs +234 kcal/day (IQR -79 to 499) for nonobese patients (P = 0.021).

CONCLUSION

Overfeeding represents an easily modifiable factor to improve outcomes in patients experiencing persistent critical illness, for which IC may be useful.

The Good, the Bad, and the Serum Creatinine: Exploring the Effect of Muscle Mass and Nutrition

Muscle wasting (sarcopenia) is one of the hallmarks of critical illness. Patients admitted to intensive care unit develop sarcopenia through increased protein catabolism, a decrease in protein syntheses, or both. Among the factors known to promote wasting are chronic inflammation and cytokine imbalance, insulin resistance, hypermetabolism, and malnutrition. Moreover, muscle wasting, known to develop in chronic kidney disease patients, is a harmful consequence of numerous complications associated with deteriorated renal function. Plenty of published data suggest that serum creatinine (SCr) reflects increased kidney damage and is also related to body weight. Based on the concept that urea and creatinine are nitrogenous end products of metabolism, the urea:creatinine ratio (UCR) could be applied but with limited clinical usability in case of kidney damage, hypovolemia, excessive, or protein intake, where UCR can be high and independent of catabolism. Recent data suggest that the sarcopenia index should be considered an alternative to serum creatinine. It is more reliable in estimating muscle mass than SCr. However, the optimal biomarker of catabolism is still an unresolved issue. The SCr is not a promising biomarker for renal function and muscle mass based on the influence of several factors. The present review highlights recent findings on the limits of SCr as a surrogate marker of renal function and the assessment modalities of nutritional status and muscle mass measurements.

Investigating the differences in nutritional status between successfully weaned and unsuccessfully weaned respirator patients

Long-term respirator users admitted to intensive care units need to be transferred to a respiratory care center (RCC) for weaning. It may cause malnutrition in critical care patients, which may manifest as a reduction in respiratory muscle mass, lower ventilatory capacity, and decreased respiratory tolerance. This study aimed to assess that if the patients' nutritional status were improved, it could help RCC patients to wean from respirators. All participants were recruited from the RCC of a medical foundation in the city and Taipei Tzu Chi Hospital. The indicators include serum albumin level, respirator detachment index, maximum inspiratory pressure (PImax), rapid shallow breathing index, and body composition measurements. We recorded the length of hospital stay, mortality, and RCW (respiratory care ward) referral rate for these participants and analyzed the differences in relevant research indicators between those who were and weren't weaned off. 43 of 62 patients were weaned from respirators, while 19 failed. The resuscitation rate was 54.8%. Patients with respirator weaning had a lower number of RCC admission days (23.1 ± 11.1 days) than respirator-dependent patients (35.6 ± 7.8 days, P < 0.05). The PImax of successfully weaned patients had a greater reduction (- 27.09 ± 9.7 cmH₂O) than unsuccessful ones (- 21.4 ± 10.2 cmH₂O, P < 0.05). The Acute Physiology and Chronic Health Evaluation II (APACHE II) scores of successfully weaned patients (15.8 ± 5.0) were lower than those who were not (20.4 ± 8.4, P < 0.05). There was no significant difference in serum albumin levels between the two groups. In the successfully weaned patients, the serum albumin concentration was increased from 2.2 ± 0.3 to 2.5 ± 0.4 mg/dL, P < 0.05. Improved nutritional status can help RCC patients to wean from respirators.

Surgical Science and the Evolution of Critical Care Medicine

Surgical science has driven innovation and inquiry across adult and pediatric disciplines that provide critical care regardless of location. Surgically originated but broadly applicable knowledge has been globally shared within the pages Critical Care Medicine over the last 50 years.

Accuracy of predictive equations for resting energy expenditure estimation in mechanically ventilated Thai patients

Background

Indirect calorimetry (IC) is the most precise approach for estimating calorie demand in critically ill patients. Despite this, owing to unaffordable devices, it is rarely used in practice. Predictive equations are the alternatives.

Objectives

To assess the accuracy of 14 predictive resting energy expenditure(REE) equations in ventilated Thai patients.

Methods

We compared the accuracy and agreement of 14 equations. The equations included the American College of Chest Physicians(ACCP) equation, Harris-Benedict equation(HBE), 1.2×HBE, 1.5×HBE, Mifflin-St. Jeor(MSJ), Ireton-Jones 1992 and 2002, Penn State 2003(HBE and MSJ) and 2010, Swinamer 1990, Faisy, Brandi 1999, and 25 kcal/kg equation. An equation was ascertained as accurate if the calculated values fell within ±10% of the measured REEs. Spearman correlation coefficient, Bland-Altman method, and intraclass correlation coefficient were used to analysis.

Results

We obtained data from 24 ventilated patients undergoing REE measurement by IC. Fifty percent of them were male with a median age of 64.5 years, a median height of 160 cm, and a median body mass index of 22.95 kg/m2. The predictive precision of all equations was poor, with largely different accuracies from 6.7% to 48.1%. The most reliable equation was Penn State 2010. The ACCP, HBE, MSJ, and Penn State 2003(HBE) tended to underestimate calorie need. Contrastingly, the other equations tended to overestimate REEs. Despite a moderate degree of correlations, the Bland-Altman plots demonstrated clinically unacceptable discrepancies between measured REE and REE calculated by each equation.

Conclusions

In ventilated Thai patients, there were no precise equations for determining REE.

Resting Energy Expenditure in the Critically Ill and Healthy Elderly-A Retrospective Matched Cohort Study

The use of indirect calorimetry to measure resting energy expenditure (mREE) is widely recommended as opposed to calculating REE (cREE) by predictive equations (PE). The aim of this study was to compare mREE with cREE in critically ill, mechanically ventilated patients aged ≥ 75 years and a healthy control group matched by age, gender and body mass index. The primary outcome was the PE accuracy rate of mREE/cREE, derived using Bland Altman plots. Secondary analyses included linear regression analyses for determinants of intraindividual mREE/cREE differences in the critically ill and interindividual mREE differences in the matched healthy cohort. In this retrospective study, 90 critically ill patients (median age 80 years) and 58 matched healthy persons were included. Median mREE was significantly higher in the critically ill (1457 kcal/d) versus the healthy cohort (1351 kcal/d), with low PE accuracy rates (21% to 49%). Independent predictors of mREE/cREE differences in the critically ill were body temperature, heart rate, FiO₂, hematocrit, serum sodium and urea. Body temperature, respiratory rate, and FiO₂ were independent predictors of interindividual mREE differences (critically ill versus healthy control). In conclusion, the commonly used PE in the elderly critically ill are inaccurate. Respiratory, metabolic and energy homeostasis variables may explain intraindividual mREE/cREE as well as interindividual mREE differences.

Associations of measured resting energy expenditure with predictive equations, NUTRIC score, and patient outcomes

Background

Indirect calorimetry is the reference method for measuring resting energy expenditure (REE), but the necessary equipment and technical expertise are not always available. Meanwhile, the NUTrition Risk in the Critically ill (NUTRIC) scale is designed to identify patients who would benefit from nutrition therapy, but no data are available regarding the association of NUTRIC scores with REE. Several predictive formulas are available as alternatives to indirect calorimetry for calculation of energy requirements, but they have not been compared in a homogeneous group of critically ill patients. The purpose of the study is to examine the correlations between energy expenditure and NUTRIC scores or patient outcomes, and to compare measured REE with estimations of energy expenditure.

Methods

In this observational, prospective study, indirect calorimetry was performed on 50 mechanically ventilated patients. Energy expenditure was also estimated with the bodyweight-based, Faisy–Fagon, and Penn-State PSU_m equations.

Results

REE was higher in patients who survived treatment than in those who died, and was positively correlated with length of stay and duration of ventilation. NUTRIC scores did not correlate with REE. The Faisy–Fagon equation overestimated expenditure, whereas PSU_m was unbiased and accurate. Calculations based on 25 kcal/kg bodyweight/day overestimated expenditure, whereas 23 kcal/kg/day produced unbiased estimates with greater accuracy than PSU_m.

Conclusion

REE was positively associated with patient outcomes. Energy expenditure was accurately predicted by calculations of 23 kcal/kg bodyweight/day.

Postpyloric feeding tube placement at the bedside: Complication rate and impact on length of stay

BACKGROUND

Postpyloric feeding tube (PPFT) placement is essential for the ongoing nutrition care of critically ill children requiring noninvasive and invasive ventilation. PPFTs are placed by a variety of providers, including advanced practice nurses (APNs), surgeons, gastroenterologists, and radiologists. Complication rates, time to enteral nutrition (EN) following placement, and association with length of stay (LOS) have not been well documented.

METHODS

A query of the electronic medical record identified patients in the pediatric intensive care unit (PICU) in whom PPFTs were placed. A retrospective chart review was performed to identify patient demographics; PPFT placement provider, indication, and duration; PICU LOS; hospital LOS; and patient pediatric risk of mortality (PRISM) scores.

RESULTS

A total of 452 PPFTs were placed in 346 patients , with 318 placed by APNs. There was only one complication in 452 placed PPFTs. PRISM scores between patient groups for APN-placed PPFTs and non-APN-placed PPFTs were not significantly different. Mean time from hospital admission to PPFT placement was 1.5 days (APN) to 2.0 days (non-APN) (P < .02). Spearman correlation coefficients demonstrated shorter hospital and PICU LOS were associated with shorter duration to insertion.

CONCLUSION

Overall complication rates of PPFT insertion is very low and do not significantly differ between provider type , even in patients with higher PRISM scores. Additionally, early time to insertion of PPFT is associated with decreased hospital and PICU LOS. Further research is needed to determine if the earlier time to insertion of PPFTs is associated with the achievement of goal feeds.

Methods for Estimating Energy Expenditure in Critically Ill Adults

Energy expenditure (EE) is the sum of metabolic activity within the body at a given time and comprises basal EE, diet-induced thermogenesis, and physical activity. In the intensive care unit, EE is most often assessed to determine a patient's caloric requirements. Energy expenditure also may be useful to understand disease states and the metabolic impact of interventions. Several methods for estimating EE are relevant for clinical use, including indirect calorimetry, predictive equations, exhaled carbon dioxide volume, and the Fick method. Indirect calorimetry is the preferred method for evaluating EE and is considered the gold standard for estimating EE in hospitalized patients. However, use of indirect calorimetry is not always practical or possible. Therefore, other methods of estimating EE must be considered. In this review, methods of evaluating EE in critically ill adults are examined and the benefits and limitations of each method are discussed, with practical considerations for use.

Development of a Resting Energy Expenditure Estimation in Patients Undergoing Targeted Temperature Management with a Surface Gel Pad Temperature Modulating Device

Targeted temperature management (TTM) directly impacts energy expenditure via temperature modulation and shivering associated with temperature modulating devices. We hypothesized that resting energy expenditure (REE) can be accurately estimated utilizing data obtained from a surface gel pad temperature modulating device (TMD) and demographic factors. Baseline demographic data, along with concurrent temperature, sedation, and shivering data, and indirect calorimetry (IDC) were collected from patients undergoing TTM. The data from the IDC and temperature modulation device (TMD) were synchronized and averaged over 60-second intervals to provide simultaneous comparisons. Heat transfer (calories) was calculated from the TMD by an equation that assessed water temperature from the TMD to the patient, water temperature returning to the TMD, water flow rates, and device mode. A linear regression model was used to determine factors associated with REE as measured by IDC. A difference in the mean between REE and estimated REE was used to assess accuracy. There were 48 assessments conducted in 40 subjects [mean (standard deviation)] age: 58 (14) years, 60% female, body surface area (BSA): 2.0 ± 0.3 who underwent simultaneous assessments. Target temperature was 36-37°C in 75%, with a median Bedside Shivering Assessment Score of 0 (range 0-2). Factors associated with REE on multivariable linear regression included older age (p < 0.001), male sex (p = 0.004), higher BSA (p < 0.001), higher patient temperature (p < 0.001), and lower heat transfer (p = 0.003). Adjusted prediction coefficients from this model were then tested against REE by a Bland-Altman analysis. The difference between difference in resting energy estimation (REEdiff) and measured REE by IDC was 6.2 calories/min (REEdiff: 95% confidence interval: -14.1 calories, 26.5 calories, p = 0.5). We believe that the heat transfer data from the TMD coupled with clinical characteristics of patients can be utilized to calculate the REE for every minute of TTM. These data can be utilized to mitigate the consequences of shivering and malnutrition during TTM.

A Single-Center Prospective Observational Study Comparing Resting Energy Expenditure in Different Phases of Critical Illness: Indirect Calorimetry Versus Predictive Equations

OBJECTIVES

Several predictive equations have been developed for estimation of resting energy expenditure, but no study has been done to compare predictive equations against indirect calorimetry among critically ill patients at different phases of critical illness. This study aimed to determine the degree of agreement and accuracy of predictive equations among ICU patients during acute phase (≤ 5 d), late phase (6-10 d), and chronic phase (≥ 11 d).

DESIGN

This was a single-center prospective observational study that compared resting energy expenditure estimated by 15 commonly used predictive equations against resting energy expenditure measured by indirect calorimetry at different phases. Degree of agreement between resting energy expenditure calculated by predictive equations and resting energy expenditure measured by indirect calorimetry was analyzed using intraclass correlation coefficient and Bland-Altman analyses. Resting energy expenditure values calculated from predictive equations differing by ± 10% from resting energy expenditure measured by indirect calorimetry was used to assess accuracy. A score ranking method was developed to determine the best predictive equations.

SETTING

General Intensive Care Unit, University of Malaya Medical Centre.

PATIENTS

Mechanically ventilated critically ill patients.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Indirect calorimetry was measured thrice during acute, late, and chronic phases among 305, 180, and 91 ICU patients, respectively. There were significant differences (F= 3.447; p = 0.034) in mean resting energy expenditure measured by indirect calorimetry among the three phases. Pairwise comparison showed mean resting energy expenditure measured by indirect calorimetry in late phase (1,878 ± 517 kcal) was significantly higher than during acute phase (1,765 ± 456 kcal) (p = 0.037). The predictive equations with the best agreement and accuracy for acute phase was Swinamer (1990), for late phase was Brandi (1999) and Swinamer (1990), and for chronic phase was Swinamer (1990). None of the resting energy expenditure calculated from predictive equations showed very good agreement or accuracy.

CONCLUSIONS

Predictive equations tend to either over- or underestimate resting energy expenditure at different phases. Predictive equations with "dynamic" variables and respiratory data had better agreement with resting energy expenditure measured by indirect calorimetry compared with predictive equations developed for healthy adults or predictive equations based on "static" variables. Although none of the resting energy expenditure calculated from predictive equations had very good agreement, Swinamer (1990) appears to provide relatively good agreement across three phases and could be used to predict resting energy expenditure when indirect calorimetry is not available.

Comparison between Nutric Score and modified nutric score to assess ICU mortality in critically ill patients with COVID-19

BACKGROUND AND AIMS

NUTrition Risk in the Critically ill (NUTRIC score) and modified Nutric score (mNUTRIC score) have been validated as screening tool for quantifying risk of adverse outcome in patients admitted in intensive care department. They differ for the measurement of IL-6 levels. In patients with COVID-19 disease the inflammatory response plays a crucial role leading to cytochine storm responsible of multiple organ damage. In this population, levels of IL-6 have been measured as indicator of inflammatory status. Aim of the study is to compare prognostic performance of both scores in predicting ICU mortality between patients with COVID-19 disease.

METHODS

A single centre, retrospective, cohort study on patients admitted in ICU with confirmed diagnosis of COVID-19 was performed. Prognostic performance of NUTRIC score and mNUTRIC score were assessed and compared for discriminative abilities for ICU-mortality.

RESULTS

43 patients were enrolled, age 64 (55; 70), BMI 28 ± 4. Mean NUTRIC score was 2.5 ± 1, mNUTRIC was 2.6 ± 1.1. Mortality was 39.5%, all patients had low nutritional risk according to both scores (≤5 and ≤ 4 for NUTRIC and mNUTRIC score respectively). The discriminative ability of Nutric Score for ICU mortality was 0.675 (95% CI: 0.524-0.825), while that of mNutric score was 0.655 (0.513-0.861), p = 0.667.

CONCLUSIONS

Prognostic performance of Nutric score and mNutric score is comparable, but the discriminative ability is low even in patients with high inflammatory status as in COVID-19 affected population. These scores may not be appropriate in patients with COVID-19 for the determination of nutritional risk.

Pathophysiology and management of critical illness polyneuropathy and myopathy

Critical illness-associated weakness (CIAW) is an umbrella term used to describe a group of neuromuscular disorders caused by severe illness. It can be subdivided into three major classifications based on the component of the neuromuscular system (i.e. peripheral nerves or skeletal muscle or both) that are affected. This includes critical illness polyneuropathy (CIP), critical illness myopathy (CIM), and an overlap syndrome, critical illness polyneuromyopathy (CIPNM). It is a common complication observed in people with critical illness requiring intensive care unit (ICU) admission. Given CIAW is found in individuals experiencing grave illness, it can be challenging to study from a practical standpoint. However, over the past 2 decades, many insights into the pathophysiology of this condition have been made. Results from studies in both humans and animal models have found that a profound systemic inflammatory response and factors related to bioenergetic failure as well as microvascular, metabolic, and electrophysiological alterations underlie the development of CIAW. Current management strategies focus on early mobilization, achieving euglycemia, and nutritional optimization. Other interventions lack sufficient evidence, mainly due to a dearth of large trials. The goal of this Physiology in Medicine article is to highlight important aspects of the pathophysiology of these enigmatic conditions. It is hoped that improved understanding of the mechanisms underlying these disorders will lead to further study and new investigations for novel pharmacologic, nutritional, and exercise-based interventions to optimize patient outcomes.

Evaluation of Measured Resting Metabolic Rate for Dietary Prescription in Ageing Adults with Overweight and Adiposity-Based Chronic Disease

The primary objective of this study was to compare weight changes in two groups of ageing Irish adults with overweight and adiposity-based chronic disease: participants who had dietary energy requirements prescribed on the base of measured RMR and participants whose RMR was estimated by a prediction equation. Fifty-four Caucasian adults (male n = 25; female n = 29, age 57.5 ± 6.3 years, weight 90.3 ± 15.1 kg, height 171.5 ± 9.5 cm, BMI 30.7 ± 4.6 kg/m²) were randomly assigned to a dietary intervention with energy prescription based on either measured RMR or estimated RMR. RMR was measured by indirect calorimetry after an overnight fast and predicted values were determined by the Mifflin et al. (1990) prediction equation. All participants received individual nutritional counselling, motivational interviewing and educational material. Anthropometric variables, blood pressure, blood glucose and blood lipid profile were assessed over 12 weeks. Body weight at week 12 was significantly lower (p < 0.05) for both groups following dietary interventions, mRMR: −4.2%; eRMR: −3.2% of initial body weight. There was no significant difference in weight loss between groups. Overall, 20.8% mRMR and 17.4% of eRMR participants experienced clinically meaningful (i.e., ≥5% of initial weight) weight reduction. Weight reduction in adults aged ≥50 years over the short term (12 weeks) favoured a reduction in blood pressure, triglycerides and glucose, thus reducing cardiovascular disease risk factors. This research indicates that employing a reduced-calorie diet using indirect calorimetry to determine energy needs when improving weight outcomes in adults (>50 years) with overweight and adiposity-based chronic disease is equal to employing a reduced-calorie diet based on the Mifflin et al. (1990) prediction equation. A reduced-energy diet based on mRMR or eRMR facilitates clinically meaningful weight reduction in adults (≥50 years) over the short term (12 weeks) and favours a reduction in blood pressure, triglycerides and glucose, thus reducing cardiovascular disease risk factors. Moreover, the addition of motivational interviewing and behaviour change techniques that support and encourage small behaviour changes is effective in short-term weight management.

Magnetron sputtered magnesium-based thin film metallic glasses for bioimplants

Mg-based thin film metallic glasses (TFMGs) can viably decrease stress shielding caused by mismatch of the modulus of elasticity between the implant material and human bone. Here, Mg-based TFMGs were fabricated onto implantable substrates by ion assisted pulsed DC magnetron sputtering. The microstructure assessment and the impact of the principle constituents of the coatings were determined utilizing an x-ray diffractometer, a transmission electron microscope, and x-ray photoelectron spectroscopy. The hardness of these thin films was estimated to be 5.1 GPa. In vitro degradation tests including electrochemical studies and immersion tests in simulated body fluid revealed that the presence of zinc could raise the corrosion resistance of Mg-based TFMG. Indirect in vitro cytotoxicity using L929 fibroblast cells revealed that the TFMGs did not induce any toxicity in cells. Biomineralization experiments using Saos-2 cells promoted the formation of calcium phosphate on its surface.

Insulin sensitivity in critically ill patients: are women more insulin resistant?

Background

Glycaemic control (GC) in intensive care unit is challenging due to significant inter- and intra-patient variability, leading to increased risk of hypoglycaemia. Recent work showed higher insulin resistance in female preterm neonates. This study aims to determine if there are differences in inter- and intra-patient metabolic variability between sexes in adults, to gain in insight into any differences in metabolic response to injury. Any significant difference would suggest GC and randomised trial design should consider sex differences to personalise care.

Methods

Insulin sensitivity (SI) levels and variability are identified from retrospective clinical data for men and women. Data are divided using 6-h blocks to capture metabolic evolution over time. In total, 91 male and 54 female patient GC episodes of minimum 24 h are analysed. Hypothesis testing is used to determine whether differences are significant (P < 0.05), and equivalence testing is used to assess whether these differences can be considered equivalent at a clinical level. Data are assessed for the raw cohort and in 100 Monte Carlo simulations analyses where the number of men and women are equal.

Results

Demographic data between females and males were all similar, including GC outcomes (safety from hypoglycaemia and high (> 50%) time in target band). Females had consistently significantly lower SI levels than males, and this difference was not clinically equivalent. However, metabolic variability between sexes was never significantly different and always clinically equivalent. Thus, inter-patient variability was significantly different between males and females, but intra-patient variability was equivalent.

Conclusion

Given equivalent intra-patient variability and significantly greater insulin resistance, females can receive the same benefit from safe, effective GC as males, but may require higher insulin doses to achieve the same glycaemia. Clinical trials should consider sex differences in protocol design and outcome analyses.

Insulin sensitivity in critically ill patients: are women more insulin resistant?

BACKGROUND

Glycaemic control (GC) in intensive care unit is challenging due to significant inter- and intra-patient variability, leading to increased risk of hypoglycaemia. Recent work showed higher insulin resistance in female preterm neonates. This study aims to determine if there are differences in inter- and intra-patient metabolic variability between sexes in adults, to gain in insight into any differences in metabolic response to injury. Any significant difference would suggest GC and randomised trial design should consider sex differences to personalise care.

METHODS

Insulin sensitivity (SI) levels and variability are identified from retrospective clinical data for men and women. Data are divided using 6-h blocks to capture metabolic evolution over time. In total, 91 male and 54 female patient GC episodes of minimum 24 h are analysed. Hypothesis testing is used to determine whether differences are significant (P < 0.05), and equivalence testing is used to assess whether these differences can be considered equivalent at a clinical level. Data are assessed for the raw cohort and in 100 Monte Carlo simulations analyses where the number of men and women are equal.

RESULTS

Demographic data between females and males were all similar, including GC outcomes (safety from hypoglycaemia and high (> 50%) time in target band). Females had consistently significantly lower SI levels than males, and this difference was not clinically equivalent. However, metabolic variability between sexes was never significantly different and always clinically equivalent. Thus, inter-patient variability was significantly different between males and females, but intra-patient variability was equivalent.

CONCLUSION

Given equivalent intra-patient variability and significantly greater insulin resistance, females can receive the same benefit from safe, effective GC as males, but may require higher insulin doses to achieve the same glycaemia. Clinical trials should consider sex differences in protocol design and outcome analyses.

The effect of age and body mass index on energy expenditure of critically ill medical patients

Background

Data on the influence of age and body mass index (BMI) on energy metabolism of the critically ill are heterogeneous. Due to the increasingly aging critically ill population, investigation on age- and BMI-specific energy metabolism is relevant.

Methods

A total of 394 indirect calorimetry measurements were conducted on 348 critically ill adult medical patients, including 46 repeat measurements after 3.6 ± 4.3 days. Measured resting energy expenditure (MREE) was compared for age groups, BMI, and gender. Predicted energy expenditure (PEE) using the Penn State, Swinamer, and Ireton-Jones equations and the ACCP recommendations was also compared with MREE.

Results

The patients were 65.6 ± 14.5 years old. Their mean Acute Physiology and Chronic Health Evaluation II score was 27.6 ± 7.8. Mean BMI was 27.8 ± 8.4 kg/m², and 25.6% were obese. MREE adjusted for ideal body weight decreased with increasing age, while it increased with increasing BMI. Age, BMI, and gender are independent determinants of MREE after adjusting for clinical factors (R² = 0.34). All four prediction equations showed a proportional bias, with the Penn State equation performing acceptably. In 46 patients with repeat indirect calorimetry, there was no significant difference between the first and second MREE (p = 0.62).

Conclusions

Age, BMI, and gender are independent determinants of resting energy expenditure in critically ill adults. Variations between measured and predicted energy expenditure are considerable. Should prediction equations be used, their performance in the specific population should be taken into consideration. Repeat indirect calorimetry may not always be necessary. However, this may depend on the length of stay and the extent of stress.

Nutrition-related outcomes and dietary intake in non-mechanically ventilated critically ill adult patients: A pilot observational descriptive study

BACKGROUND

Critically ill patients who do not receive invasive mechanical ventilation (IMV) are a growing population, experiencing complex interventions that may impair dietary intake and nutrition-related outcomes.

OBJECTIVES

The objectives of this study were to quantify intake and nutrition-related outcomes of non-IMV critically ill patients and to establish feasibility of methods to measure nutrition-related outcomes in this population.

METHODS

Non-IMV adult patients expected to remain in the intensive care unit (ICU) for ≥24 h were eligible. Nutrition-related outcomes were assessed at baseline by subjective global assessment (SGA); on alternate study days by mid-upper arm circumference (MUAC), calf circumference (CC), and ultrasound of quadriceps muscle layer thickness (QMLT); and daily by body weight and bioelectrical impedance analysis (BIA). Data were censored at day 5 or ICU discharge. Dietary intake from all sources, including oral intake via investigator-led weighed food records, was quantified on days 1-3. Feasibility was defined as data completion rate ≥70%. Data are expressed as mean (standard deviation) or median [interquartile range (IQR)].

RESULTS

Twenty-three patients consented (50% male; 53 [42-64] y; ICU stay: 2.8 [1.9-4.0] d). Nutrition-related outcomes at baseline and ICU discharge were as follows: MUAC: 33.2 (8.6) cm (n = 18) and 29.3 (5.4) cm (n = 6); CC: 39.5 (7.4) cm (n = 16) and 37.5 (6.2) cm (n = 6); body weight: 95.3 (34.8) kg (n = 19) and 95.6 (41.0) kg (n = 10); and QMLT: 2.6 (0.8) cm (n = 15) and 2.5 (0.3) cm (n = 5), respectively. Oral intake provided 3155 [1942-5580] kJ and 32 [20-53] g protein, with poor appetite identified as a major barrier. MUAC, CC, QMLT, and SGA were feasible, while BIA and body weight were not.

CONCLUSIONS

Oral intake in critically ill patients not requiring IMV is below estimated requirements, largely because of poor appetite. The small sample and short study duration were not sufficient to quantify changes in nutrition-related outcomes. MUAC, CC, QMLT, and SGA are feasible methods to assess nutrition-related outcomes at a single time point in this population.

Administration of enteral nutrition in the prone position, gastric residual volume and other clinical outcomes in critically ill patients: a systematic review

This systematic review of longitudinal studies aimed to evaluate the effect of enteral feeding of critically ill adult and pediatric patients in the prone position on gastric residual volume and other clinical outcomes. A literature search was conducted in the databases PubMed, Scopus and Embase using terms related to population and intervention. Two independent reviewers analyzed the titles and abstracts, and data collection was performed using a standardized form. Discrepancies were resolved by a third reviewer. The methodological quality of the studies was evaluated considering the potential for systematic errors, and the data were qualitatively analyzed. Four studies with adult patients and one with preterm patients were included. The gastric residual volume was evaluated as the main outcome: three studies did not show differences in the gastric residual volume between the prone and supine positions (p > 0.05), while one study showed a higher gastric residual volume during enteral feeding in the prone position (27.6mL versus 10.6mL; p < 0.05), and another group observed a greater gastric residual volume in the supine position (reduction of the gastric residual volume by 23.3% in the supine position versus 43.9% in the prone position; p < 0.01). Two studies evaluated the frequency of vomiting; one study found that it was higher in the prone position (30 versus 26 episodes; p < 0.001), while the other study found no significant difference (p > 0.05). The incidence of aspiration pneumonia and death were evaluated in one study, with no difference between groups (p > 0.05). The literature on the administration of enteral feeding in the prone position in critically ill patients is sparse and of limited quality, and the results regarding gastric residual volume are contradictory. Observational studies with appropriate sample sizes should be conducted to support conclusions on the subject.

Daily systemic energy expenditure in the acute phase of aneurysmal subarachnoid hemorrhage

Background: Patients with subarachnoid hemorrhage often have impaired consciousness and cannot regulate nutritional intakes themselves. Previous studies have demonstrated elevated energy expenditure in the acute phase, but it is not known whether the energy demand is constant during the first week after onset of the disease. In this study, we performed daily measurements of energy expenditure with indirect calorimetry during the first 7 days after aneurysmal subarachnoid hemorrhage in mechanically ventilated patients.Methods: Metabolic measurements were performed daily with indirect calorimetry in 26 patients with aneurysmal subarachnoid hemorrhage. All patients were intubated and mechanically ventilated. The measured value was compared to the predicted values from the Harris-Benedict equation and the Penn State University 1998 equation. Urinary nitrogen excretion was measured daily.Results: There was a significant increase in energy expenditure during days 2-3 compared to days 5-6. The Harris-Benedict equation underestimated metabolic demand. The Penn State 1998 equation was closer to the measured values, but still underestimated caloric need. Urinary nitrogen excretion increased throughout the first week from initially low values.Conclusions: There is a dynamic course in energy expenditure in patients with aneurysmal subarachnoid hemorrhage, with increasing metabolic demand during the first week of the disease. Indirect calorimetry could be used more often to help provide an adequate amount of energy.

Standardized nutritional supply versus individual nutritional assessment: Impact on weight changes, complications and functional outcome from neurological early rehabilitation

BACKGROUND & AIMS

Approximately 55% of neurological and neurosurgical early rehabilitation (NNER) patients are in need of enteral nutrition, but long-term nutritional assessment of these critically ill patients is suboptimal. Therefore, this study analyzed the effect of an individual nutritional assessment on weight changes during rehabilitation and impact on complications and functional outcome.

METHODS

170 NNER patients on enteral nutrition were enrolled in the study. According to the initial ward, patients were assigned to receive standardized enteral nutrition (n = 107, control group) or an individual nutritional assessment (n = 63, intervention group). Weight changes, complications, assessment of the functional outcome (Early Rehabilitation Index, Barthel Index, Early Rehabilitation Barthel Index) and the length of stay were recorded and compared between groups using non-parametric tests for non-paired samples (Mann-Whitney U test for metric data or the χ² test for categorical data) or paired samples (Wilcoxon test). In addition, daily energy requirement was calculated and compared with daily intake. Correlation analysis by Spearman was performed to investigate linear relationship between weight changes and the difference of administered and calculated calories in both study groups.

RESULTS

A weight loss was observed in the control group, whereas the weight of the intervention group remained stable over time. The difference between calculated and administered calories correlated with weight changes in the control group. Regarding complications during rehabilitation, control patients showed more frequently impaired diuresis. In addition, control patients were suffering longer from diarrhea than patients of the intervention group. Both groups improved in functional status to a comparable degree. Relationships between these improvements and weight changes or administered calories could not be found.

CONCLUSIONS

Individual nutritional assessment had not an additional affect for the improvement of functional outcome or the prevention of complications. However, weight turned out to be more stable and signs of nutritional incompatibilities are less frequent among patients being treated with an individualized nutritional assessment.

Nutrition delivery, workload and performance in a model-based ICU glycaemic control system

BACKGROUND AND OBJECTIVE

Hyperglycaemia is commonplace in the adult intensive care unit (ICU), and has been associated with increased morbidity and mortality. Effective glycaemic control (GC) can reduce morbidity and mortality, but has proven difficult. STAR is a model-based GC protocol that uniquely maintains normoglycaemia by changing both insulin and nutrition interventions, and has been proven effective in controlling blood glucose (BG) in the ICU. However, most ICU GC protocols only change insulin interventions, making the variable nutrition aspect of STAR less clinically desirable. This paper compares the performance of STAR modulating only insulin, with three simpler alternative nutrition protocols in clinically evaluated virtual trials.

METHODS

Alternative nutrition protocols are fixed nutrition rate (100% caloric goal), CB (Cahill et al. best) stepped nutrition rate (60%, 80% and 100% caloric goal for the first 3 days of GC, and 100% thereafter) and SLQ (STAR lower quartile) stepped nutrition rate (65%, 75% and 85% caloric goal for the first 3 days of GC, and 85% thereafter). Each nutrition protocol is simulated with the STAR insulin protocol on a 221 patient virtual cohort, and GC performance, safety and total intervention workload are assessed.

RESULTS

All alternative nutrition protocols considerably reduced total intervention workload (14.6-19.8%) due to reduced numbers of nutrition changes. However, only the stepped nutrition protocols achieved similar GC performance to the current variable nutrition protocol. Of the two stepped nutrition protocols, the SLQ nutrition protocol also improved GC safety, almost halving the number of severe hypoglycaemic cases (5 vs. 9, P = 0.42).

CONCLUSIONS

Overall, the SLQ nutrition protocol was the best alternative to the current variable nutrition protocol, but either stepped nutrition protocol could be adapted by STAR to reduce workload and make it more clinically acceptable, while maintaining its proven performance and safety.

Indirect calorimetry in critically ill mechanically ventilated patients: Comparison of E-sCOVX with the deltatrac

BACKGROUND & AIMS

Indirect calorimetry is recommended to measure energy expenditure (EE) in critically ill, mechanically ventilated patients. The most validated system, the Deltatrac® (Datex-Ohmeda, Helsinki, Finland) is no longer in production. We tested the agreement of a new breath-by-breath metabolic monitor E-sCOVX® (GE healthcare, Helsinki, Finland), with the Deltatrac. We also compared the performance of the E-sCOVX to commonly used predictive equations.

METHODS

We included mechanically ventilated patients eligible to undergo indirect calorimetry. After a stabilization period, EE was measured simultaneously with the Deltatrac and the E-sCOVX for 2 h. Agreement and precision of the E-sCOVX was tested by determining bias, limits of agreement and agreement rates compared to the Deltatrac. Performance of the E-sCOVX was also compared to four predictive equations: the 25 kcal/kg, Penn State University 2003b, Faisy, and Harris-Benedict equation.

RESULTS

We performed 29 measurements in 16 patients. Mean EE-Deltatrac was 1942 ± 274 kcal/day, and mean EE-E-sCOVX was 2177 ± 319 kcal/day (p < 0.001). E-sCOVX overestimated EE with a bias of 235 ± 149 kcal/day, being 12.1% of EE-Deltatrac. Limits of agreement were -63 to +532 kcal/day. The 10% and 15% agreement rates of EE-E-sCOVX compared to the Deltatrac were 34% and 72% respectively. The bias of E-sCOVX was lower than the bias of the 25 kcal/kg-equation, but higher than bias of the other equations. Agreement rates for E-sCOVX were similar to the equations. The Faisy-equation had the highest 15% agreement rate.

CONCLUSION

The E-sCOVX metabolic monitor is not accurate in estimating EE in critically ill mechanically ventilated patients when compared to the Deltatrac, the present reference method. The E-sCOVX overestimates EE with a bias and precision that are clinically unacceptable.

What Happens to Nutrition Intake in the Post-Intensive Care Unit Hospitalization Period? An Observational Cohort Study in Critically Ill Adults

BACKGROUND

Little is currently known about nutrition intake and energy requirements in the post-intensive care unit (ICU) hospitalization period in critically ill patients. We aimed to describe energy and protein intake, and determine the feasibility of measuring energy expenditure during the post-ICU hospitalization period in critically ill adults.

METHODS

This is a nested cohort study within a randomized controlled trial in critically ill patients. After discharge from ICU, energy and protein intake was quantified periodically and indirect calorimetry attempted. Data are presented as n (%), mean (SD), and median (interquartile range [IQR]).

RESULTS

Thirty-two patients were studied in the post-ICU hospitalization period, and 12 had indirect calorimetry. Mean age and BMI was 56 (18) years and 30 (8) kg/m² , respectively, 75% were male, and the median estimated energy and protein requirement were 2000 [1650-2550] kcal and 112 [84-129] g, respectively. Oral nutrition either alone (n = 124 days, 55%) or in combination with enteral nutrition (n = 96 days, 42%) was the predominant mode. Over 227 total days in the post-ICU hospitalization period, a median [IQR] of 1238 [869-1813] kcal and 60 [35-89.5] g of protein was received from nutrition therapy. In the 12 patients who had indirect calorimetry, the median measured daily energy requirement was 1982 [1843-2345] kcal and daily energy deficit was -95 [-1050 to 347] kcal compared with the measured energy requirement.

CONCLUSIONS

Energy and protein intake in the post-ICU hospitalization period was less than estimated and measured energy requirements. Oral nutrition provided alone was the most common mode of nutrition therapy.

Prescribed hypocaloric nutrition support for critically-ill adults

BACKGROUND

There are controversies about the amount of calories and the type of nutritional support that should be given to critically-ill people. Several authors advocate the potential benefits of hypocaloric nutrition support, but the evidence is inconclusive.

OBJECTIVES

To assess the effects of prescribed hypocaloric nutrition support in comparison with standard nutrition support for critically-ill adults SEARCH METHODS: We searched the Cochrane Central Register of Controlled Trials (CENTRAL, Cochrane Library), MEDLINE, Embase and LILACS (from inception to 20 June 2017) with a specific strategy for each database. We also assessed three websites, conference proceedings and reference lists, and contacted leaders in the field and the pharmaceutical industry for undetected/unpublished studies. There was no restriction by date, language or publication status.

SELECTION CRITERIA

We included randomized and quasi-randomized controlled trials comparing hypocaloric nutrition support to normo- or hypercaloric nutrition support or no nutrition support (e.g. fasting) in adults hospitalized in intensive care units (ICUs).

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures expected by Cochrane. We meta-analysed data for comparisons in which clinical heterogeneity was low. We conducted prespecified subgroup and sensitivity analyses, and post hoc analyses, including meta-regression. Our primary outcomes were: mortality (death occurred during the ICU and hospital stay, or 28- to 30-day all-cause mortality); length of stay (days stayed in the ICU and in the hospital); and Infectious complications. Secondary outcomes included: length of mechanical ventilation. We assessed the quality of evidence with GRADE.

MAIN RESULTS

We identified 15 trials, with a total of 3129 ICU participants from university-associated hospitals in the USA, Colombia, Saudi Arabia, Canada, Greece, Germany and Iran. There are two ongoing studies. Participants suffered from medical and surgical conditions, with a variety of inclusion criteria. Four studies used parenteral nutrition and nine studies used only enteral nutrition; it was unclear whether the remaining two used parenteral nutrition. Most of them could not achieve the proposed caloric targets, resulting in small differences in the administered calories between intervention and control groups. Most studies were funded by the US government or non-governmental associations, but three studies received funding from industry. Five studies did not specify their funding sources.The included studies suffered from important clinical and statistical heterogeneity. This heterogeneity did not allow us to report pooled estimates of the primary and secondary outcomes, so we have described them narratively.When comparing hypocaloric nutrition support with a control nutrition support, for hospital mortality (9 studies, 1775 participants), the risk ratios ranged from 0.23 to 5.54; for ICU mortality (4 studies, 1291 participants) the risk ratios ranged from 0.81 to 5.54, and for mortality at 30 days (7 studies, 2611 participants) the risk ratios ranged from 0.79 to 3.00. Most of these estimates included the null value. The quality of the evidence was very low due to unclear or high risk of bias, inconsistency and imprecision.Participants who received hypocaloric nutrition support compared to control nutrition support had a range of mean hospital lengths of stay of 15.70 days lower to 10.70 days higher (10 studies, 1677 participants), a range of mean ICU lengths of stay 11.00 days lower to 5.40 days higher (11 studies, 2942 participants) and a range of mean lengths of mechanical ventilation of 13.20 days lower to 8.36 days higher (12 studies, 3000 participants). The quality of the evidence for this outcome was very low due to unclear or high risk of bias in most studies, inconsistency and imprecision.The risk ratios for infectious complications (10 studies, 2804 participants) of each individual study ranged from 0.54 to 2.54. The quality of the evidence for this outcome was very low due to unclear or high risk of bias, inconsistency and imprecisionWe were not able to explain the causes of the observed heterogeneity using subgroup and sensitivity analyses or meta-regression.

AUTHORS' CONCLUSIONS

The included studies had substantial clinical heterogeneity. We found very low-quality evidence about the effects of prescribed hypocaloric nutrition support on mortality in hospital, in the ICU and at 30 days, as well as in length of hospital and ICU stay, infectious complications and the length of mechanical ventilation. For these outcomes there is uncertainty about the effects of prescribed hypocaloric nutrition, since the range of estimates includes both appreciable benefits and harms.Given these limitations, results must be interpreted with caution in the clinical field, considering the unclear balance of the risks and harms of this intervention. Future research addressing the clinical heterogeneity of participants and interventions, study limitations and sample size could clarify the effects of this intervention.

Energy Requirements in Critically Ill Patients

During the management of critical illness, optimal nutritional support is an important key for achieving positive clinical outcomes. Compared to healthy people, critically ill patients have higher energy expenditure, thereby their energy requirements and risk of malnutrition being increased. Assessing individual nutritional requirement is essential for a successful nutritional support, including the adequate energy supply. Methods to assess energy requirements include indirect calorimetry (IC) which is considered as a reference method, and the predictive equations which are commonly used due to the difficulty of using IC in certain conditions. In this study, a literature review was conducted on the energy metabolic changes in critically ill patients, and the implications for the estimation of energy requirements in this population. In addition, the issue of optimal caloric goal during nutrition support is discussed, as well as the accuracy of selected resting energy expenditure predictive equations, commonly used in critically ill patients.

Adequacy of nutrition support during extracorporeal membrane oxygenation

BACKGROUND

The use of veno-venous extracorporeal membrane oxygenation (vv-ECMO) is increasing in adults with severe respiratory failure. Observational data suggest that there are significant challenges to providing adequate nutrition support for patients on vv-ECMO. We aimed to describe firstly the nutrition support practices in a large single-centre providing vv-ECMO to adults and secondly any association with clinical outcome.

METHODS

We conducted a retrospective review of patients receiving vv-ECMO on the Intensive Care Unit (ICU) of a large London teaching hospital. Adult patients admitted to the ICU with severe respiratory failure between December 2010 and December 2015 were included. Daily energy and protein delivery were compared with estimated targets and reasons for feeding interruptions were collected from electronic medical records. Adequate feeding was defined as 80-110% of estimated targets.

RESULTS

We analysed 203 eligible patients. Median duration of ICU stay was 21.0 (IQR, 15.0-33.0) days and vv-ECMO 10.0 (IQR, 7.0-16.0) days. Although median energy (89.8% (IQR, 80.5-96.0%)) and protein (84.7% (IQR, 74.0-96.7%)) delivery was adequate, underfeeding of either energy or protein occurred on nearly one third (28.3%) of nutrition support days. A higher admission severity of illness score was associated with inadequate protein delivery (p = 0.040). Patients with more severe organ dysfunction on the first day of vv-ECMO received inadequate energy (p = 0.026). The most common reasons for interrupted feeding were medical procedures (39.1%) followed by poor gastric motility (22.8%).

CONCLUSION

Adequate energy and protein delivery during vv-ECMO is possible but underfeeding is still common, especially in those who are more severely ill or who have more severe organ dysfunction. Patients with inadequate energy or protein delivery did not differ in ICU and 6-month survival. Prospective studies investigating optimal feeding in this patient cohort are required.

Enteral/Parenteral Nutrition in Foals and Adult Horses Practical Guidelines for the Practitioner

Nutritional support is an important adjunct to medical therapy in the sick, injured, or debilitated equine patient. What is not clear is the optimal route, composition, or amounts of support. The enteral route should be chosen whenever possible to maximize the benefits to the gastrointestinal tract and the patient as a whole. Complete or partial parenteral nutrition is most useful as a bridge during recovery and transition to enteral feeding in the horse. The reader is encouraged to consider nutritional support whether enteral or parenteral in any anorexic, chronically debilitated, or sick equine patient.

Nutrition delivery of a model-based ICU glycaemic control system

BACKGROUND

Hyperglycaemia is commonplace in the adult intensive care unit (ICU), associated with increased morbidity and mortality. Effective glycaemic control (GC) can reduce morbidity and mortality, but has proven difficult. STAR is a proven, effective model-based ICU GC protocol that uniquely maintains normo-glycaemia by changing both insulin and nutrition interventions to maximise nutrition in the context of GC in the 4.4-8.0 mmol/L range. Hence, the level of nutrition it provides is a time-varying estimate of the patient-specific ability to take up glucose.

METHODS

First, the clinical provision of nutrition by STAR in Christchurch Hospital, New Zealand (N = 221 Patients) is evaluated versus other ICUs, based on the Cahill et al. survey of 158 ICUs. Second, the inter- and intra- patient variation of nutrition delivery with STAR is analysed. Nutrition rates are in terms of percentage of caloric goal achieved.

RESULTS

Mean nutrition rates clinically achieved by STAR were significantly higher than the mean and best ICU surveyed, for the first 3 days of ICU stay. There was large inter-patient variation in nutrition rates achieved per day, which reduced overtime as patient-specific metabolic state stabilised. Median intra-patient variation was 12.9%; however, the interquartile range of the mean per-patient nutrition rates achieved was 74.3-98.2%, suggesting patients do not deviate much from their mean patient-specific nutrition rate. Thus, the ability to tolerate glucose intake varies significantly between, rather than within, patients.

CONCLUSIONS

Overall, STAR's protocol-driven changes in nutrition rate provide higher nutrition rates to hyperglycaemic patients than those of 158 ICUs from 20 countries. There is significant inter-patient variability between patients to tolerate and uptake glucose, where intra-patient variability over stay is much lower. Thus, a best nutrition rate is likely patient specific for patients requiring GC. More importantly, these overall outcomes show high nutrition delivery and safe, effective GC are not exclusive and that restricting nutrition for GC does not limit overall nutritional intake compared to other ICUs.

Development and Validation of a New Cardio-Specific Resting Energy Expenditure Equation for Adults

BACKGROUND

This study tested the accuracy of resting energy expenditure (REE) equations among patients who underwent cardiopulmonary bypass and developed/validated a more accurate cardio-specific equation (CSE).

MATERIALS AND METHODS

Prospective observational cohort of 240 adults (derivation data set, 170 patients; validation data set, 70 patients). REEs were calculated with 6 equations-Penn State 2003a, Penn State 2003b, Ireton-Jones, Swinamer, Faisy, and American College of Chest Physicians-and results were compared with indirect calorimetry (IC). Multivariable linear regression analysis was used to develop the CSE. Agreement between measured and calculated REEs was assessed with Lin's concordance correlation coefficient (LCCC), Bland-Altman plot, and regression analysis.

RESULTS

LCCCs present poor agreement between measured and calculated REEs: 0.24 (95% CI, 0.19-0.29), for the Faisy equation; 0.15 (95% CI, 0.1-0.19), Ireton-Jones; 0.31 (95% CI, 0.25-0.37), Swinamer; 0.17 (95% CI, 0.13-0.21), Penn State 2003a; 0.19 (95% CI, 0.14-0.23), Penn State 2003b; and 0.11 (95% CI, 0.07-0.15), American College of Chest Physicians. Based on the derivation data set, REEs are explained by the following equation: CSE = 616 - 8 × age in years + 13 × weight in kilograms + 450 if on ventilator + 159 × MV in liters + 145 if on inotropes. Based on the validation study results, the LCCC between IC and the CSE was 0.82 (95% CI, 0.73-0.88).

CONCLUSION

The CSE has adequate precision and could be used for REE estimation for patients undergoing cardiopulmonary bypass if IC is unavailable.

Effects of a Gastric Feeding Protocol on Efficiency of Enteral Nutrition in Critically Ill Infants and Children

Objective: Enteral nutrition (EN) has well-established benefits in critically ill children. Optimally, full nutritional support should be achieved expeditiously. The authors hypothesized that a protocolized continuous gastric EN (GEN) approach would decrease time to goal feeding rate and calories (TTG). Design: 96 patients were enrolled, divided equally into control (pre) and treatment (post) groups. Patients were monitored every 4 hours for 5 signs of feeding intolerance. Significance was defined as P < .05. Setting: 23-bed multidisciplinary pediatric intensive care unit (PICU). Subjects: PICU patients <18 years of age in whom GEN was to be started were eligible. Exclusion criteria included patients receiving total parental nutrition, <24 hours postoperative, had transpyloric feeding, had previous fundoplication, had preexisting gastrointestinal disease or chronic regimen. Interventions: The authors instituted a protocolized, weight-based approach to GEN and collected outcomes and tolerance data on both the control and treatment groups. Measurements and Main Results: There was no difference in TTG between the control and treatment groups. However, for patients less than 10 kg (74/96 patients), TTG was 15 hours faster in the treatment group compared with the control (56.85 ± 22.71, 70.44 ± 32.45 hours, respectively). Conclusions: The authors investigated the value of a GEN protocol in improving efficiency to goal nutrition in critically ill children. While no difference was found overall, in the subgroup analysis (77%) a significant improvement in TTG was found in infants <10 kg. Further investigation is needed to define impact on patient outcomes, such as length of stay, weight gain, and ICU morbidities.

Generalisability of a Virtual Trials Method for Glycaemic Control in Intensive Care

BACKGROUND

Elevated blood glucose (BG) concentrations (Hyperglycaemia) are a common complication in critically ill patients. Insulin therapy is commonly used to treat hyperglycaemia, but metabolic variability often results in poor BG control and low BG (hypoglycaemia).

OBJECTIVE

This paper presents a model-based virtual trial method for glycaemic control protocol design, and evaluates its generalisability across different populations.

METHODS

Model-based insulin sensitivity (SI) was used to create virtual patients from clinical data from three different ICUs in New Zealand, Hungary, and Belgium. Glycaemic results from simulation of virtual patients under their original protocol (self-simulation) and protocols from other units (cross simulation) were compared.

RESULTS

Differences were found between the three cohorts in median SI and inter-patient variability in SI. However, hour-to-hour intra-patient variability in SI was found to be consistent between cohorts. Self and cross-simulation results were found to have overall similarity and consistency, though results may differ in the first 24-48 h due to different cohort starting BG and underlying SI.

CONCLUSIONS AND SIGNIFICANCE

Virtual patients and the virtual trial method were found to be generalisable across different ICUs. This virtual trial method is useful for in silico protocol design and testing, given an understanding of the underlying assumptions and limitations of this method.

Protein Requirements of the Critically Ill Pediatric Patient

This article includes a review of protein needs in children during health and illness, as well as a detailed discussion of protein metabolism, including nitrogen balance during critical illness, and assessment and prescription/delivery of protein to critically ill children. The determination of protein requirements in children has been difficult and challenging. The protein needs in healthy children should be based on the amount needed to ensure adequate growth during infancy and childhood. Compared with adults, children require a continuous supply of nutrients to maintain growth. The protein requirement is expressed in average requirements and dietary reference intake, which represents values that cover the needs of 97.5% of the population. Critically ill children have an increased protein turnover due to an increase in whole-body protein synthesis and breakdown with protein degradation leading to loss of lean body mass (LBM) and development of growth failure, malnutrition, and worse clinical outcomes. The results of protein balance studies in critically ill children indicate higher protein needs, with infants and younger children requiring higher intakes per body weight compared with older children. Monitoring the side effects of increased protein intake should be performed. Recent studies found a survival benefit in critically ill children who received a higher percentage of prescribed energy and protein goal by the enteral route. Future randomized studies should evaluate the effect of protein dosing in different age groups on patient outcomes, including LBM, muscle structure and function, duration of mechanical ventilation, intensive care unit and hospital length of stay, and mortality.

Clinically Relevant Differences in Accuracy of Enteral Nutrition Feeding Pump Systems

BACKGROUND

There are clinically relevant discrepancies between prescribed volumes and delivered volumes of enteral nutrition (EN) in intensive care unit (ICU) patients. Next to EN-protocol violations due to insufficient care, we hypothesized technical factors to be responsible for this deficit. The aim of this study was to determine the accuracy of EN feeding pump systems frequently used in the ICU.

METHODS

Thirteen commercially available EN feeding pumps with their own delivery systems were tested in 12 sessions with different EN feeding tubes and EN formulas in a laboratory setting. The reproducibility of the measurements was determined for the 8 best performing EN feeding pump systems.

RESULTS

There were clinically important differences between prescribed volumes and delivered volumes of EN in the tested EN feeding pump systems. The deficit in volume ranged from +66 mL (surplus of 66 mL) to -271 mL (deficit of 271 mL) per 24 hours (14% of prescribed volume). Viscosity of test fluids (water/EN feeding formulas) and resistance of test tubes had no influence on the delivered volume by the tested EN feeding pump systems, because differences between prescribed volumes and delivered volumes were consistently found for each system while varying these test settings.

CONCLUSIONS

Differences between prescribed and delivered EN volumes are caused by the function and construction of EN feeding pump systems. To improve nutrition therapy, the flow rate has to be adjusted or the best-performing EN feeding pump has to be purchased.

The History of Nonsurgical Enteral Tube Feeding Access

Specialized nutrition support, particularly enteral feeding, has been used for centuries. Technologic advancements have affected the provision of enteral feeding. Feeding solutions and devices, as well as the techniques to place the feeding devices, have evolved. This article reviews the history of bedside placement methods for short-term enteral access devices.

Nutritional Alterations Associated with Neurological and Neurosurgical Diseases

Neurological and neurosurgical diseases lead to complications producing malnutrition increasing pathology and mortality. In order to avoid complications because of malnutrition or overcome deficiencies in nutrients supplements are often used for these subjects. The physiopathological mechanisms of malnutrition, methods of nutritional assessment and the supplemental support are reviewed in this paper based on the assumption that patients need to receive adequate nutrition to promote optimal recovery, placing nutrition as a first line treatment and not an afterthought in the rehabilitation.

Extracorporeal Life Support in Pediatric and Neonatal Critical Care: A Review

Extracorporeal life support (ECLS) is a modified form of cardiopulmonary bypass used to provide prolonged tissue oxygen delivery in patients with respiratory and/or cardiac failure. The first large-scale success of ECLS was achieved in the management of term newborns with respiratory failure. ECLS has become an accepted therapeutic modality for neonates, children, and adults who have failed conventional therapy and in whom cardiac and/or respiratory insufficiency is potentially reversible. The use of ECLS allows one to reduce other cardiopulmonary supports and apply a gentle ventilation strategy in a population of severely compromised critical care patients. ECLS has now been employed in more than 26,000 neonatal and pediatric patients with an overall survival rate of 68%. ECLS has evolved significantly over 25 years of clinical practice; patient selection for this complex and highly invasive therapy, as well as how ECLS is employed in different patient groups, is constantly changing. Generally, ECLS is used more liberally now than in the past. The number of patients requiring this support, however, is declining yearly, and those patients who receive ECLS compose a more severe subset of an intensive care population. This review provides an overview of the development of ECLS and the equipment and techniques employed. The use of ECLS for neonatal respiratory failure, pediatric respiratory failure, and cardiac support are outlined. Management of the ECLS patient is discussed in detail, and outcome of these patients is reviewed. Finally, current trends and future implications of ECLS in neonatal and pediatric critical care are addressed.