Dietary protein in the ICU in relation to health outcomes.

PURPOSE OF REVIEW: Critical care nutrition guidelines recommend provision of higher protein doses than recommended in health. These recommendations have been predominately based on lower quality evidence and physiological rationale that greater protein doses may attenuate the significant muscle loss observed in critically ill patients. This review discusses the mechanistic action of protein in the critically ill, details results from recent trials on health outcomes, discusses considerations for interpretation of trial results, and provides an overview of future directions. RECENT FINDINGS: Two recent large clinical trials have investigated different protein doses and the effect on clinical outcome. Important findings revealed potential harm in certain sub-groups of patients. This harm must be balanced with the potential for beneficial effects on muscle mass and physical function given that two recent systematic reviews with meta-analyses demonstrated attenuation of muscle loss with higher protein doses. Utilizing biological markers such as urea: creatinine ratio or urea levels may prove useful in monitoring harm from higher protein doses. SUMMARY: Future research should focus on prospectively investigating biological signatures of harm as well as taking into the consideration elements that will likely enhance the effectiveness of protein dose.

Nutrition intake, muscle thickness, and recovery outcomes for critically ill patients requiring non-invasive forms of respiratory support: A prospective observational study.

BACKGROUND: Use of high-flow nasal cannula (HFNC) and non-invasive ventilation (NIV) in the intensive care unit (ICU) is increasing, yet reporting of nutrition intake, muscle thickness, or recovery outcomes in this population is limited. OBJECTIVE: The objective of this study was to quantify muscle thickness, nutrition intake, and functional recovery outcomes for patients receiving HFNC/NIV within the ICU. METHODS: A single-centre, prospective, observational study in adult ICU patients recruited within 48 hrs of commencing HFNC/NIV. Change in quadriceps muscle layer thickness using ultrasound (primary outcome) and 24 hr nutrition intake from study inclusion to day 7 (D7), functional capacity (Barthel Index), and quality of life (EuroQol five-dimension five-level utility index) at D90 were assessed. Data are n (%), mean ± standard deviation or median [interquartile range], are compared using paired sample t-test, and a P value of <0.05 was considered significant. RESULTS: Primary outcome data were available for n = 28/42: 64 ± 13 y, 61% male, body mass index: 29.1 ± 9.0 kg/m2, and Acute Physiology and Chronic Health Evaluation II score: 17 ± 5. Quadriceps muscle layer thickness reduced from 2.41 ± 0.87 to 2.12 ± 0.73 cm; mean difference: -0.29 cm (95% confidence interval: -0.44, -0.13). Nutrition intake increased from study inclusion to D7: 1735 ± 1283 to 5448 ± 2858 kJ and 17.4 ± 16.6 to 60.9 ± 36.8g protein. Barthel Index was 87 ± 20 at baseline and 91 ± 15 at D90 (out of 100). Quality of life was impaired at D90: 0.64 ± 0.23 (health = 1.0). CONCLUSION: Critically ill patients receiving HFNC/NIV experienced muscle loss and impaired quality of life.

Evaluating physiological barriers to oral intake in hospitalized patients: A secondary analysis.

BACKGROUND: Oral intake in hospitalized patients is frequently below estimated targets. Multiple physiological symptoms are proposed to impact oral intake, yet many have not been quantified objectively. AIM: To describe the challenges of objectively measuring physiological nutrition-impacting symptoms in hospitalized patients. METHOD: A secondary analysis of data from a single-center, descriptive cohort study of physiological nutrition-impacting symptoms in intensive care unit (ICU) survivors and general medical patients was conducted. Demographic and clinical characteristics were extracted for patients who completed the original study and collected retrospectively for those who were screened and recruited but did not complete the original study. Reasons for patient exclusion from the original study were quantified from the screening database. Descriptive data are reported as mean ± SD, median [interquartile range], or number (percentage). RESULTS: ICU survivors and general medical patients were screened for inclusion in the original study between March 1 and December 23, 2021. Of the 644 patients screened, 97% did not complete the study, with 93% excluded at screening. Of the 266 ICU survivors and 398 general medical patients screened, 89% and 95% were excluded, respectively. Major exclusion criteria included the inability to follow commands or give informed consent (n = 155, 25%), the inability to consume the easy-to-chew and thin-fluid buffet meal, and imminent discharge (both, n = 120, 19%). CONCLUSION: Understanding physiological factors that drive reduced oral intake in hospitalized patients is challenging. Exclusion criteria required to objectively quantify physiological nutrition-impacting symptoms significantly preclude participation and likely act as independent barriers to oral intake.

Comparison of energy intake in critical illness survivors, general medical patients, and healthy volunteers: A descriptive cohort study.

BACKGROUND: Intensive care unit (ICU) survivors have reduced oral intake; it is unknown whether intake and associated barriers are unique to this group. OBJECTIVE: To quantify energy intake and potential barriers in ICU survivors compared with general medical (GM) patients and healthy volunteers. DESIGN: A descriptive cohort study in ICU survivors, GM patients, and healthy volunteers. Following an overnight fast, participants consumed a 200 ml test-meal (213 kcal) and 180 min later an ad libitum meal to measure energy intake (primary outcome). Secondary outcomes; taste recognition, nutrition-impacting symptoms, malnutrition, and quality of life (QoL). Data are mean ± SD, median (interquartile range [IQR]) or number [percentage]). RESULTS: Twelve ICU survivors (57 ± 17 years, BMI: 30 ± 6), eight GM patients (69 ± 19 years, BMI: 30 ± 6), and 25 healthy volunteers (58 ± 27 years, BMI: 25 ± 4) were included. Recruitment ceased early because of slow recruitment and SARS-CoV-2. Energy intake was lower in both patient groups than in health (ICU: 289 [288, 809], GM: 426 [336, 592], health: 815 [654, 1165] kcal). Loss of appetite was most common (ICU: 78%, GM: 67%). For ICU survivors, GM patients and healthy volunteers, respectively, severe malnutrition prevalence; 40%, 14%, and 0%; taste identification; 8.5 [7.0, 11.0], 8.5 [7.0, 9.5], and 8.0 [6.0, 11.0]; and QoL; 60 [40-65], 50 [31-55], and 90 [81-95] out of 100. CONCLUSIONS: Energy intake at a buffet meal is lower in hospital patients than in healthy volunteers but similar between ICU survivors and GM patients. Appetite loss potentially contributes to reduced energy intake.