Protein requirements for critically ill ventilator-dependent patients with COVID-19

Clinical practice guidelines for nutritional assessment and monitoring of adult ICU patients in China

The Chinese Society of Critical Care Medicine (CSCCM) has developed clinical practice guidelines for nutrition assessment and monitoring for patients in adult intensive care units (ICUs) in China. This guideline focuses on nutrition evaluation and metabolic monitoring to achieve optimal and personalized nutrition therapy for critically ill patients. This guideline was developed by experts in critical care medicine and evidence-based medicine methodology and was developed after a thorough review of the system and a summary of relevant trials or studies published from 2000 to July 2023. A total of 18 recommendations were formed and consensus was reached through discussions and reviews by expert groups in critical care medicine, parenteral and enteral nutrition, and surgery. The recommendations are based on currently available evidence and cover several key fields, including screening and assessment, evaluation and assessment of enteral feeding intolerance, metabolic and nutritional measurement and monitoring during nutrition therapy, and organ function evaluation related to nutrition supply. Each question was analyzed according to the Population, Intervention, Comparison, and Outcome (PICO) principle. In addition, interpretations were provided for four questions that did not reach a consensus but may have potential clinical and research value. The plan is to update this nutrition assessment and monitoring guideline using the international guideline update method within 3-5 years.

Potential benefits of using an energy-dense, high-protein formula enriched with β-hydroxy-β-methylbutyrate, fructo-oligosaccharide, and vitamin D for enteral feeding in the ICU: A pilot case-control study in COVID-19 patients

OBJECTIVES

The aim of this study was to investigate the potential benefits of using an energy-dense, high-protein (HP) formula enriched with β-hydroxy-β-methylbutyrate (HMB), fructo-oligosaccharide (FOS), and vitamin D (VitD) for enteral feeding in the intensive care unit (ICU).

METHODS

This was a nested case-control multicenter study. Mechanically ventilated patients with COVID-19 in whom enteral nutrition was not contraindicated and receiving an energy-dense, HP-HMB-FOS-VitD formula (1.5 kcal/mL; 21.5% of calories from protein; n = 53) were matched (1:1) by age (±1 y), sex, body mass index (±1 kg/m²) and Sequential Organ Failure Assessment score (±1 point) and compared with patients fed with a standard HP, fiber-free formula (1.25-1.3 kcal/mL; 20% of calories from protein; n = 53). The primary end point was daily protein intake (g/kg) on day 4. Protein-calorie intake on day 7, gastrointestinal intolerance, and clinical outcomes were addressed as secondary end points.

RESULTS

The use of a HP-HMB-FOS-VitD formula resulted in higher protein intake on days 4 and 7 (P = 0.006 and P = 0.013, respectively), with similar energy intake but higher provision of calories from enteral nutrition at both times (P <0 .001 and P = 0.017, respectively). Gastrointestinal tolerance was superior, with fewer patients fed with a HP-HMB-FOS-VitD formula reporting at least one symptom of intolerance (55 versus 74%; odds ratio [OR], 0.43; 95% confidence interval [CI], 0.18-0.99; P = 0.046) and constipation (38 versus 66%; OR, 0.27; 95% CI, 0.12-0.61; P = 0.002). A lower rate of ICU-acquired infections was also observed (42 versus 72%; OR, 0.29; 95% CI, 0.13-0.65; P = 0.003), although no difference was found in mortality, ICU length of stay, and ventilation-free survival.

CONCLUSIONS

An energy-dense, HP-HMB-FOS-VitD formula provided a more satisfactory protein intake and a higher provision of caloric intake from enteral nutrition than a standard HP formula in mechanically ventilated patients with COVID-19. Lower rates of gastrointestinal intolerance and ICU-acquired infections were also observed.

Association of nitrogen balance trajectories with clinical outcomes in critically ill COVID-19 patients: A retrospective cohort study

BACKGROUND & AIMS

The intensity and duration of the catabolic phase in COVID-19 patients can differ between survivors and non-survivors. The purpose of the study was to assess the determinants of, and association between, nitrogen balance trajectories and outcome in critically ill COVID-19 patients.

METHODS

This retrospective monocentric observational study involved patients admitted to the intensive care unit (ICU) of the University Hospital of Clermont Ferrand, France, from January 2020 to May 2021 for COVID-19 pneumonia. Patients were excluded if referred from another ICU, if their ICU length of stay was <72 h, or if they were treated with renal replacement therapy during the first seven days after ICU admission. Data were collected prospectively at admission and during ICU stay. Death was recorded at the end of ICU stay. Comparisons of the time course of nitrogen balance according to outcome were analyzed using two-way ANOVA. At days 3, 5, 7, 10 and 14, uni- and multivariate logistic regression analyses were performed to assess the impact of a non-negative nitrogen-balance on ICU death. To investigate the relationships between nitrogen balance, inflammatory markers and protein intake, linear and non-nonlinear models were run at days 3, 5 and 7, and the amount of protein intake necessary to reach a neutral nitrogen balance was calculated. Subgroup analyses were carried out according to BMI, age, and sex.

RESULTS

99 patients were included. At day 3, a similar negative nitrogen balance was observed in survivors and non-survivors: -16.4 g/d [-26.5, -3.3] and -17.3 g/d [-22.2, -3.8] (p = 0.54). The trajectories of nitrogen balance over time thus differed between survivors and non-survivors (p = 0.01). In survivors, nitrogen balance increased over time, but decreased from day 2 to day 6 in non-survivors, and thereafter increased slowly up to day 14. At days 5 and 7, a non-negative nitrogen-balance was protective from death. Administering higher protein amounts was associated with higher nitrogen balance.

CONCLUSION

We report a prolonged catabolic state in COVID patients that seemed more pronounced in non-survivors than in survivors. Our study underlines the need for monitoring urinary nitrogen excretion to guide the amount of protein intake required by COVID-19 patients.

Nitrogen balance and outcomes in critically ill patients: A systematic review and meta-analysis

Objective

Nitrogen balance (NB) is a commonly used nutrition indicator in clinical practice, while its relation to the interpretation of protein malnutrition and outcomes in critically ill patients remains unclear. This study aimed to evaluate the impact of NB on prognosis in such a patient population.

Methods

We searched for relevant studies in PubMed, EMBASE, and the Cochrane Database up to May 10, 2022. Meta-analyses were performed to evaluate the relationship between NB (initial, final, or absolute change of NB levels) and prognosis and important clinical outcomes in critically ill patients. Pooled odds ratios (ORs) and mean differences (MDs) together with their 95% confidence intervals (CIs) were calculated. We also conducted subgroup analyses to explore the sources of heterogeneity.

Results

Eight studies with 1,409 patients were eligible. These studies were moderate to high quality. When pooled, the initial NB was comparable between the survival and non-survival groups (five studies, MD 1.20, 95% CI, −0.70 to 3.11, I2 = 77%; P = 0.22), while a significantly higher final NB in the survival group than that in the death group (two studies, MD 3.69, 95% CI, 1.92–5.46, I2 = 55%; P &lt; 0.0001). Two studies provided the absolute change of NB over time and suggested survival patients had more increased NB (MD 4.16 g/day, 95% CI, 3.70–4.61, I2 = 0%; P &lt; 0.00001). Similarly, for studies utilizing multivariate logistic regression, we found an improved NB (four studies, OR 0.85, 95% CI, 0.73–0.99, I2 = 61%; P = 0.04) but not an initial NB (two studies, OR 0.92, 95% CI 0.78–1.08, I2 = 55%; P = 0.31) was significantly associated the risk of all-cause mortality. These results were further confirmed in subgroup analyses. In addition, patients with improved NB had more protein and calorie intake and a similar length of stay in hospital than those without.

Conclusions

Our results suggested that an improved NB but not the initial NB level was associated with all-cause mortality in critically ill patients. This highlights the requirement for dynamic monitoring of NB during nutrition treatment. Further randomized clinical trials examining the impact of NB-guided protein intake on clinical outcomes in critically ill patients are warranted.

Systematic review registration

INPLASY202250134, https://doi.org/10.37766/inplasy2022.5.0134.