The dilemma of protein delivery in the intensive care unit

Nutrition Therapy in Critically Ill Patients with Obesity: An Observational Study

BACKGROUND

Critically ill patients with obesity (PwO) have anthropometric characteristics that can be associated with different nutritional-metabolic requirements than other critically ill patients. However, recommendations regarding nutrition delivery in PwO are not clearly established among the different published clinical practice guidelines (CPGs). Our main aim was to evaluate the impact of energy and protein intake in critically ill PwO.

METHODS

A multicenter (n = 37) prospective observational study was performed. Adult patients requiring medical nutrition therapy (MNT) were included, and PwO (BMI ≥ 30 Kg·m-2) were analyzed. Demographic data, comorbidities, nutritional status, and the average caloric and protein delivery administered in the first 14 days, including complications and outcomes, were recorded in a database. Patients were classified and analyzed based on the adequacy of energy and protein intake according to CPG recommendations.

RESULTS

525 patients were included, of whom 150 (28.6%) had obesity. The energy delivery was considered inadequate (<11 Kcal/Kg/d) in 30.7% (n = 46) and adequate (≥11 Kcal/Kg/d) in 69.3% (n = 104) of cases. PwO who received adequate energy delivery had greater use of the parenteral route and longer mean hospital stays (28.6 ± 26.1 vs. 39.3 ± 28.1; p = 0.01) but lower ICU mortality (32.6% vs. 16.5%; p = 0.02). Protein delivery was inadequate (<0.8 g/Kg/d) in 63.3% (n = 95), insufficient (0.8-1.2 g/Kg/d) in 31.33% (n = 47), and adequate (≥1.2 g/Kg/d) in only 5.4% (n = 8) of patients. PwO with inadequate protein delivery-compared with insufficient delivery-had higher use of the parenteral route and lower mortality in the ICU (25.5% vs. 14.9%; p = 0.02). Multivariate analysis revealed that PwO who received adequate energy delivery (hazard ratio [HR]: 0.398; 95% confidence interval [CI]: 0.180-0.882; p = 0.023) had better survival, while patients with insufficient protein delivery (HR: 0.404; CI 95%: 0.171-0.955; p = 0.038) had better survival than those with inadequate delivery.

CONCLUSION

PwO can frequently receive inadequate energy and protein delivery from MNT during an ICU stay, which may impact the short-term mortality of these critically ill patients. It is emerging to develop strategies to optimize MNT delivery in these patients, which may improve their outcomes. NCT Registry: 03634943.

Course of measured energy expenditure over the first 10 days of critical illness: A nested prospective study in an adult surgical ICU

BACKGROUND & AIMS

Various factors may cause significant daily variations in energy expenditure in and between critically patients. This nested, prospective study (ClinicalTrials.gov Identifier: NCT04099108) in a predominantly trauma surgical ICU, aimed to determine the course of measured energy expenditure over the first 10 days of critical illness, and to identify factors contributing to energy expenditure.

METHODS

Indirect calorimetry was performed on alternate days from ICU Day 3 ± 1 until Day 10 ± 1. The mean daily measured energy expenditure, respiratory quotient and total energy delivery as a percentage of measured energy expenditure were modelled using linear mixed regression with two fractional polynomial terms to accommodate non-linear responses over time.

RESULTS

Fifty ICU patients (mean age 36.9 ± 11.8 years, Acute Physiology and Chronic Health Evaluation (APACHE II) 13.5 ± 6.6, Sequential Organ Failure Assessment (SOFA) 4.5 ± 3.2) were included. Mean body mass index (BMI) was 24.8 ± 4.0 kg/m2 and mean ventilation duration 7.7 ± 2.7 days. Mean daily measured energy expenditure showed a significant non-linear response (p = 0.006) increasing over the first 4 days peaking on day 5 and then plateauing. Mean daily respiratory quotient increased over the first 7 days, thereafter plateauing with a slight downward trend from day 8 despite a progressive increase in total energy delivery as a percentage of measured energy expenditure. Mean daily measured energy expenditure was significantly lower in the early than in the late acute phases (p = 0.024), whereas the late- and post-acute phases were similar. Age, sex and BMI significantly influenced measured energy expenditure.

CONCLUSION

Measured energy expenditure showed a significant non-linear response over the first 10 days in ICU, increasing over the first 4 days peaking on day 5 then plateauing. The observed variability highlights the complexity of managing critically ill patients and the importance of personalised nutrition therapy. Additionally, the observed trend with a peak in measured energy expenditure around day five could inform timing and strategies for nutritional intervention in this patient cohort.

Parenteral Nutrition: Current Use, Complications, and Nutrition Delivery in Critically Ill Patients

BACKGROUND

Parenteral nutrition (PN) is needed to avoid the development of malnutrition when enteral nutrition (EN) is not possible. Our main aim was to assess the current use, complications, and nutrition delivery associated with PN administration in adult critically ill patients, especially when used early and as the initial route. We also assessed the differences between patients who received only PN and those in whom EN was initiated after PN (PN-EN).

METHODS

A multicenter (n = 37) prospective observational study was performed. Patient clinical characteristics, outcomes, and nutrition-related variables were recorded. Statistical differences between subgroups were analyzed accordingly.

RESULTS

From the entire population (n = 629), 186 (29.6%) patients received PN as initial nutrition therapy. Of these, 74 patients (11.7%) also received EN during their ICU stay (i.e., PN-EN subgroup). PN was administered early (<48 h) in the majority of patients (75.3%; n = 140) and the mean caloric (19.94 ± 6.72 Kcal/kg/day) and protein (1.01 ± 0.41 g/kg/day) delivery was similar to other contemporary studies. PN showed similar nutritional delivery when compared with the enteral route. No significant complications were associated with the use of PN. Thirty-two patients (43.3%) presented with EN-related complications in the PN-EN subgroup but received a higher mean protein delivery (0.95 ± 0.43 vs 1.17 ± 0.36 g/kg/day; p = 0.03) compared with PN alone. Once adjusted for confounding factors, patients who received PN alone had a lower mean protein intake (hazard ratio (HR): 0.29; 95% confidence interval (CI): 0.18-0.47; p = 0.001), shorter ICU stay (HR: 0.96; 95% CI: 0.91-0.99; p = 0.008), and fewer days on mechanical ventilation (HR: 0.85; 95% CI: 0.81-0.89; p = 0.001) compared with the PN-EN subgroup.

CONCLUSION

The parenteral route may be safe, even when administered early, and may provide adequate nutrition delivery. Additional EN, when possible, may optimize protein requirements, especially in more severe patients who received initial PN and are expected to have longer ICU stays. NCT Registry: 03634943.