Evaluation of the effect of high protein supply on diaphragm atrophy in critically ill patients receiving prolonged mechanical ventilation

Association between protein intake and functional capacity in critically ill patients: A retrospective cohort study

BACKGROUND

Intensive care unit (ICU) protein benchmarks are based on mortality and morbidity; whether these targets also support functional recovery is unknown. We assessed whether different protein doses influenced patients' functional capacity, measured by the Chelsea Physical Assessment score (CPAx).

METHODS

Single-center retrospective cohort study on ICU survivors with length of stay ≥7 days admitted between October 2014 and September 2020. Eligible patients were divided according to protein intake (g/kg/day): low (<0.8), medium (0.8-1.19), high (1.2-1.5), and very high (>1.5). Protein dose effect on CPAx was assessed at ICU discharge with analysis of covariance adjusting for age, illness severity, hospital length of stay before ICU admission, time to start nutrition support, and mechanical ventilation duration. We also investigated effect modification by energy intake and nutrition status.

RESULTS

Enrolled patients (n = 531) were similar for age, nutrition status, and illness severity across groups. CPAxs were nonlinearly associated with protein doses and similar among low, medium, and very high groups. The CPAx for the high group was statistically different (P = 0.014), indicating that the data of three groups could be pooled. Mean CPAx difference remained statistically significant after adjusting for confounding variables (3.9 ± 1.8, P = 0.029 in the four-group model, and 2.7 ± 0.9, P = 0.003 in the pooled two-group model). Energy intake was equivalent between groups and did not modify CPAx. The high group had superior CPAx in both well-nourished and malnourished patients, indicating nutrition status was not an effect modifier.

CONCLUSION

Protein dose 1.2-1.5 g/kg/day was associated with superior functional capacity at ICU discharge compared with other doses. Neither energy intake nor nutrition status modified functional capacity across groups; therefore, the results appear to be influenced by 1.2-1.5 g/kg/day.

The impact of guideline recommended protein intake on mortality and length of intensive care unit and hospital stay in critically ill adults: A systematic review

International guidelines recommend a target protein intake of ≥1.2 g/kg/day to all critically ill patients for optimal outcomes. There are however various conflicting data related to this recommendation. The primary objective of this review was to compare a protein intake group (≥1.2 g/kg/day) with a lower protein intake group (<1.2 g/kg/day) in critically ill adult patients on mortality, length of intensive care unit (ICU) and hospital stay. Secondly, the effect of protein intake on length of mechanical ventilation, adverse nutrition-related events and muscle mass and strength parameters were investigated. Sixteen randomised controlled trials (RCTs) of adult patients admitted to an intensive or high care unit and receiving nutrition support in the form of enteral- and/or parenteral nutrition were selected against prespecified eligibility criteria. Two independent reviewers extracted relevant data and assessed the risk of bias of the included studies. Review Manager 5.4.1 was used to analyse data and GRADE (Grading of Recommendations, Assessment, Development, and Evaluations) was used to evaluate the certainty of the evidence. The higher protein group, when compared to the lower protein group, probably results in little to no difference in mortality (risk ratio [RR] 1.01; 95% confidence interval [CI]: 0.89 to 1.14; moderate-certainty evidence); with a probable slight increase in length of ICU stay (mean difference [MD] 0.33; 95% CI -0.57 to 1.23; moderate-certainty) and length of hospital stay (MD 1.72; 95% CI -0.58 to 4.01; moderate-certainty evidence), on average. For secondary outcomes, it was found that the higher protein group probably does not reduce the length of mechanical ventilation (MD 0.08; 95% CI -0.38 to 0.53; moderate-certainty evidence). Higher protein group probably reduces the occurrence of diarrhoea and high gastric residual volume and may reduce the occurrence of constipation. It may also increase nitrogen balance (MD 3.66; 95% CI 1.81 to 5.51; low-certainty evidence). Importantly, there does not seem to be harm associated with the higher protein group, though it should be mentioned that for many of the adverse events in this study, the certainty of evidence was low or very low.

Incidence, outcome, and prognostic factors of prolonged mechanical ventilation among children in Chinese mainland: a multi-center survey

Objective

To evaluate the incidence, outcome, and prognostic factors of prolonged mechanical ventilation (PMV) in children in Mainland China.

Methods

A prospective study was conducted in 11 pediatric intensive care units (PICUs) from May 1, 2021, to April 30, 2022. All pediatric patients on mechanical ventilation meeting the criteria for PMV were included in the study.

Results

Out of 5,292 patients receiving mechanical ventilation, 278 children met the criteria for PMV (5.3%). After excluding case with incomplete data or lost to follow-up, the study included 250 patients. Among them, 115 were successfully weaned from mechanical ventilation, 90 died, and 45 were still on mechanical ventilation. The 6-month survival rate was 64%. The primary associated conditions of PMV were lower airway diseases (36%), central nervous system diseases (32%), and neuromuscular diseases (14%). The stepwise multiple logistic regression analysis indicated that the utilization of vasoactive agents and an elevated pediatric logistic organ dysfunction-2 (PELOD-2) score on the day of PMV diagnosis were significantly associated with an increased of PMV death. Specifically, the odds ratio (OR) for vasoactive agent use was 2.86; (95% CI: 0.15-0.84; P = 0.018), and for the PELOD-2 score, it was 1.37; 95% CI: 1.17-1.61; P < .001). Conversely, early rehabilitation intervention was negatively associated with the risk of PMV death (OR = 0.45; 95% CI: 0.22-0.93; P = .032). Furthermore, the tracheotomy timing emerged as an independent predictor of failure to wean from PMV, with an OR of 1.08, (95% CI: 1.01-1.16; P = .030).

Conclusions

The study revealed a 5.3% incidence of PMV in children requiring mechanical ventilation in China. The use of vasoactive agents and a higher PELOD-2 score at PMV diagnosis were significantly associated with an increased risk of PMV death, whereas early rehabilitation intervention was identified as crucial for improving patient outcomes. The timing of tracheostomy was identified as a high-risk factor for failure to wean from mechanical ventilation.

No benefit of higher protein dosing in critically ill patients: a systematic review and meta-analysis of randomized controlled trials

Purpose

The optimal range of protein dosage and effect of high-dose protein on critically ill patients remain controversial. We conducted a meta-analysis to compare higher and lower doses of protein supplementation for nutritional support in critically ill patients.

Methods

We searched the PubMed, Embase, Scopus, and Cochrane Library databases for randomized controlled trials that compared higher (≥1.2 g/kg per day) versus lower (<1.2 g/kg per day) doses of protein supplementation among critically ill adult patients. This search spanned from the inception of relevant databases to November 20, 2023. Our primary endpoint of interest was overall mortality, while secondary endpoints included length of stay in the intensive care unit, length of hospital stay, duration of mechanical ventilation, and incidence of acute kidney injury.

Results

Seventeen studies including 2,965 critically ill patients were included in our meta-analysis. The pooled analyses showed no significant difference in overall mortality (RR 1.03, 95%CI [0.92-1.15], P = 0.65, I2 = 0%), length of intensive care unit stay (MD 0.19, 95%CI [-0.67 to 1.04], P = 0.66, I2 = 25%), length of hospital stay (MD 0.73, 95%CI [-1.59 to 3.04], P = 0.54, I2 = 27%), duration of mechanical ventilation (MD -0.14, 95%CI [-0.83 to 0.54], P = 0.68, I2 = 8%), and incidence of acute kidney injury (RR 1.11, 95%CI [0.87-1.41], P = 0.38, I2 = 0%) between critically ill patients receiving higher or lower doses of protein supplementation.

Conclusions

For critically ill patients, the protein supplementation dose had no significant effect on clinical outcomes, including overall mortality, length of intensive care unit and hospital stay, duration of mechanical ventilation, and incidence of acute kidney injury.

Definition, diagnosis, and treatment of respiratory sarcopenia

PURPOSE OF REVIEW

Skeletal muscle weakness and wasting also occurs in the respiratory muscles, called respiratory sarcopenia. Respiratory sarcopenia may lead to worse clinical indicators and outcomes. We present a novel definition and diagnostic criteria for respiratory sarcopenia, summarize recent reports on the association between respiratory sarcopenia, physical and nutritional status, and clinical outcomes, and provide suggestions for the prevention and treatment of respiratory sarcopenia.

RECENT FINDINGS

Recently, a novel definition and diagnostic criteria for respiratory sarcopenia have been prepared. Respiratory sarcopenia is defined as a condition in which there is both low respiratory muscle strength and low respiratory muscle mass. Respiratory muscle strength, respiratory muscle mass, and appendicular skeletal muscle mass are used to diagnose respiratory sarcopenia. Currently, it is challenging to definitively diagnose respiratory sarcopenia due to the difficulty in accurately determining low respiratory muscle mass. Decreased respiratory muscle strength and respiratory muscle mass are associated with lower physical and nutritional status and poorer clinical outcomes. Exercise interventions, especially respiratory muscle training, nutritional interventions, and their combinations may effectively treat respiratory sarcopenia. Preventive interventions for respiratory sarcopenia are unclear.

SUMMARY

The novel definition and diagnostic criteria will contribute to promoting the assessment and intervention of respiratory sarcopenia.

High protein provision of more than 1.2 g/kg improves muscle mass preservation and mortality in ICU patients: A systematic review and meta-analyses

BACKGROUND

ICU patients lose muscle mass rapidly and maintenance of muscle mass may contribute to improved survival rates and quality of life. Protein provision may be beneficial for preservation of muscle mass and other clinical outcomes, including survival. Current protein recommendations are expert-based and range from 1.2 to 2.0 g/kg. Thus, we performed a systematic review and meta-analysis on protein provision and all clinically relevant outcomes recorded in the available literature.

METHODS

We conducted a systematic review and meta-analyses, including studies of all designs except case control and case studies, with patients aged ≥18 years with an ICU stay of ≥2 days and a mean protein provision group of ≥1.2 g/kg as compared to <1.2 g/kg with a difference of ≥0.2 g/kg between protein provision groups. All clinically relevant outcomes were studied. Meta-analyses were performed for all clinically relevant outcomes that were recorded in ≥3 included studies.

RESULTS

A total of 29 studies published between 2012 and 2022 were included. Outcomes reported in the included studies were ICU, hospital, 28-day, 30-day, 42-day, 60-day, 90-day and 6-month mortality, ICU and hospital length of stay, duration of mechanical ventilation, vomiting, diarrhea, gastric residual volume, pneumonia, overall infections, nitrogen balance, changes in muscle mass, destination at hospital discharge, physical performance and psychological status. Meta-analyses showed differences between groups in favour of high protein provision for 60-day mortality, nitrogen balance and changes in muscle mass.

CONCLUSION

High protein provision of more than 1.2 g/kg in critically ill patients seemed to improve nitrogen balance and changes in muscle mass on the short-term and likely 60-day mortality. Data on long-term effects on quality of life are urgently needed.

Protein supplementation in critical illness: why, when and how?

PURPOSE OF REVIEW

In critically ill patients, optimal protein provision remains a challenge given the wide range in recommended protein delivery in international guidelines and the lack of robust, high quality evidence. As patients are confronted with poor functional outcomes after admission, often attributed to muscle wasting and persisting for multiple years, there is a pressing need for optimal nutritional strategies in the ICU, particularly including protein. This review will discuss the recent literature with regard to purpose, timing and mode of protein delivery.

RECENT FINDINGS

Recent studies on the effect of dose and timing of protein on clinical and functional outcomes are largely observational in nature and the protein delivery considered as "high" still often only nears the lower end of current recommendations. The majority of trials observed no effect of protein supplementation on mortality, muscle strength or function, though some report attenuation of muscle volume loss, especially when combined with muscle activation. There is no strong evidence that ICU patients should receive supplementation with any specific amino acids.

SUMMARY

Though adequate protein provision is likely important, it is difficult to come to a uniform conclusion regarding dosing and timing due to conflicting results in mostly observational studies as well as different cut-off values for high, moderate and low protein intake. This topic is currently subject to large clinical trials.

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.