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(9) Assessment of gastrointestinal function during enteral nutrition treatment
During enteral nutrition, the enteral nutrition tolerance score scale [70] (Table 4) can be used to assess the patient's feeding tolerance.
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Gastrointestinal function assessment: (1) Normal gastrointestinal function: 0 points; (2) Mild impairment of gastrointestinal function: 1 to 2 points; (3) Moderate impairment of gastrointestinal function: 3 to 4 points; (4) Stomach Severe impairment of intestinal function: 5 points and above.
When feeding intolerance occurs during enteral nutrition, the patient's enteral nutrition tolerance score needs to be assessed every 6 to 8 hours, and the enteral nutrition infusion is adjusted based on the score results: (1) Increase in score If the score is ≤1 point: continue enteral nutrition and increase the speed; (2) The score increases by 2 to 3 points: continue enteral nutrition, maintain the original speed or slow down the speed, and receive symptomatic treatment; (3) The score increases by ≥4 points or the total score ≥5 points: suspend enteral nutrition and handle accordingly
Recommendation 26: The enteral nutrition tolerance score is recommended as a tool to assess patients' gastrointestinal tolerance.
[4. Parenteral nutrition treatment for critically ill neurosurgery patients]
(1) Timing to start parenteral nutrition treatment
Enteral nutrition for critically ill neurological patients is affected by many factors, making it sometimes difficult to achieve nutritional goals. When enteral nutrition cannot achieve nutritional goals, and if the patient is in a state of long-term nutritional deficiencies, supplementing parenteral nutrition is uncontroversial. However, the optimal timing of initiation of supplemental parenteral nutrition is controversial.
It has been suggested that, after 3 days of ICU admission, when the energy level provided by enteral nutrition cannot reach 60%, supplementary parenteral nutrition should be initiated to achieve a maximum of 100% of energy requirements (indirect calorimetry). However, the EPaNIC study [71] observed that early parenteral nutrition is associated with prolonged ICU length of stay and mechanical ventilation, increased infection rates, and the need for renal replacement therapy. These findings may be related to formulating energy targets based on predictive formulas rather than indirect calorimetry, thereby giving excess energy. Reveals the potential harm of giving complete, potentially overestimated energy goals to critically ill patients during the acute phase. However, it is unclear whether the use of indirect calorimetry for target setting in studies would lead to different results, and the optimal time to initiate supplemental parenteral nutrition to achieve complete caloric requirements is also uncertain.
ASPEN/SCCM recommends that if >60% of energy and protein requirements cannot be met by enteral routes alone, supplemental parenteral nutrition should be considered after 7 to 10 days. This recommendation is based on an assessment that supplementing parenteral nutrition with enteral nutrition before days 7 to 10 after ICU admission does not improve clinical outcomes and may even have harmful consequences. However, there are currently no data to support starting parenteral nutrition after day 8 or comparing the effects of starting parenteral nutrition between days 4 to 7 versus days 8 to 10.
Recommendation 27: For critically ill neurosurgery patients who still cannot achieve nutritional goals (80% EE by indirect calorimetry, 60% by predictive formula) despite maximizing enteral nutrition strategies, enteral therapy may be considered after 7 to 10 days. External nutrition. It is not recommended to initiate parenteral nutrition therapy early.
(2) Selection of parenteral nutrition treatment preparations
Parenteral nutrition is an important part of nutritional therapy, and the configuration of its nutritional solution has always attracted widespread attention. Premixed parenteral nutrition and compound parenteral nutrition are the two main types of parenteral nutrition. The advantages and disadvantages of the two have attracted widespread attention from clinicians. Premixed parenteral nutrition minimizes compounding errors and improves safety; compounded parenteral nutrition can achieve individualized treatment based on the patient's actual condition.
1. Comparison of compound parenteral nutrition and premixed parenteral nutrition formulas: Both compound parenteral nutrition and premixed parenteral nutrition can basically meet the nutritional needs of patients. Compound parenteral nutrition has a large gap between the caloric nitrogen ratio and sugar-to-lipid ratio and the recommended values, while the caloric-to-nitrogen ratio and sugar-to-lipid ratio in premixed parenteral nutrition are more ideal.
A clinical survey collected 1,207 prescriptions for parenteral nutrition from 6 different regional hospitals to compare premixed parenteral nutrition and compound parenteral nutrition in terms of nutrient supply, total liquid volume, non-protein calories, total nitrogen, Differences in indicators such as thermal nitrogen ratio. Both compound parenteral nutrition and premixed parenteral nutrition can basically meet the nutritional needs of patients. Compound parenteral nutrition is consistent with the recommended caloric-to-nitrogen ratio [(180~250):1], sugar-to-lipid ratio [(0.56~1.26):1] and the recommended ratio of heat-to-nitrogen [(100~150):1], sugar-to-lipid ratio ( 1.0∶1), there is a large gap, and the thermal nitrogen ratio (167:1) and sugar-lipid ratio (0.8:1) in premixed parenteral nutrition are more ideal [72].
2. Comparison of complications between compound parenteral nutrition and premixed parenteral nutrition: The blood infection rate of patients treated with premixed parenteral nutrition is lower than that of patients treated with compound parenteral nutrition.
Two retrospective analyzes of bloodstream infections associated with parenteral nutrition included 113,342 patients receiving parenteral nutrition. The experimental group consisted of 7,925 patients receiving premixed parenteral nutrition; the control group consisted of 105,417 patients receiving compound parenteral nutrition. Baseline differences, risk factors, and potential confounders were adjusted by using multivariate logistic regression, and propensity score matching was used as a sensitivity analysis. The blood infection rate of premixed parenteral nutrition was lower than that of compound parenteral nutrition (19.6% vs. 25.9%, P<0.001; 11.3% vs. 16.1%, P<0.0001) [72, 73].
A retrospective analysis of 49 patients with gastrointestinal symptoms caused by combined parenteral nutrition and premixed parenteral nutrition. The control group consisted of 29 patients receiving compound parenteral nutrition; the experimental group consisted of 20 patients receiving premixed parenteral nutrition. All patients in the experimental group developed nausea symptoms, and 6 patients in the control group developed nausea symptoms. The control group had better gastrointestinal tolerance.
Recommendation 28: Both compound parenteral nutrition and premixed parenteral nutrition can meet the basic needs of patients who require supplementary parenteral nutrition treatment. Premixed parenteral nutrition has a low blood infection rate and high safety, so it can be the first choice. For patients who need to supplement more electrolytes or have higher nutritional needs, compound parenteral nutrition can be selected for personalized parenteral nutrition.
(3) Timing to terminate parenteral nutrition therapy
The purpose of parenteral nutrition therapy is to enable patients to maintain nutritional status, gain weight, and heal wounds even when they are unable to eat normally. For corresponding patients, if parenteral nutrition is stopped prematurely, the patient will be at risk of malnutrition and complications; however, the longer the parenteral nutrition is continued, the greater the risk of catheter-related infection and parenteral nutrition-related liver disease [74 ]. Therefore, for critically ill neurosurgical patients on parenteral nutrition, efforts should always be made to convert the patient to enteral therapy. In order to avoid overfeeding, while increasing enteral nutrition, the energy from the parenteral route should be appropriately reduced. Once the supply of enteral nutrition exceeds 60% of the target energy demand and can still be gradually increased, parenteral nutrition can be terminated.
Recommendation 29: It is recommended that critically ill neurosurgery patients who receive parenteral nutrition and have no contraindications to enteral nutrition should strive to switch to enteral nutrition. As the amount of enteral nutrition increases, the amount of parenteral nutrition should be reduced accordingly. Energy, until enteral nutrition reaches 60% of the energy goal, parenteral nutrition can be terminated.
[5. Use of nutritional therapy additives in critically ill neurosurgery patients]
(1) Micronutrients and antioxidants
Providing micronutrients containing a variety of trace elements and vitamins is an integral part of nutritional therapy. The difference between parenteral and enteral formulations is that generally parenteral formulations do not contain micronutrients for stability reasons, so parenteral formulations need to be added separately. Studies have shown that micronutrient deficiencies are related to poor prognosis in critically ill patients [75]. However, there is controversy about whether micronutrient supplementation can improve prognosis, which may be related to patient differences.
Oxidative stress is defined as an imbalance between increased nitroxide radical reactions and endogenous antioxidant mechanisms. Commonly seen in patients with septic shock, severe pancreatitis, acute respiratory distress syndrome, severe burns and trauma.
Antioxidant micronutrients, mainly copper, selenium, zinc and vitamins E and C. In severe inflammatory conditions, their circulating levels drop below normal reference values. Note that these micronutrients often require higher doses when used as antioxidants and should not be confused with the nutrient doses required for daily supplementation. Doses exceeding 10 times the DRI are not recommended in clinical settings if severe deficiency is not demonstrated.
1. Selenium: The antioxidant mechanism of selenium is to activate the activity of glutathione peroxidase family antioxidant enzymes. Low selenium levels are associated with severe inflammation, organ failure, and poor prognosis. In a meta-analysis that included 9 trials with a total of 792 patients with sepsis, the safety of high-dose selenium treatment (1000-4000 mg) was studied [76] and was observed to help reduce the risk of sepsis in sepsis. Case fatality rate. However, in the REDOXS trial, selenium supplementation did not show this effect [77]. The meta-analysis by Manzanares et al [78] and the German cohort study [79] did not find any improvement in clinical efficacy. Also, since selenium is excreted by the kidneys, doses above the DRI should be avoided in cases of renal failure.
2. Vitamin C: Critically ill patients have lower blood concentrations of vitamin C. Low plasma concentrations are associated with inflammation, severity of organ failure, and mortality. Preclinical studies have shown that high-dose vitamin C can prevent or restore microcirculatory blood flow damage by inhibiting the activation of nicotinamide adenine dinucleotide phosphate oxidase and inducible nitric oxide synthase, and can also prevent thrombin-induced Platelet aggregation and the expression of selectins on platelet surfaces, thereby preventing the formation of microthrombi [80]. Additionally, it restores vascular responsiveness to vasoconstrictors and protects the endothelial barrier by maintaining cyclic guanylate phosphatase, blocking phosphorylation, and preventing apoptosis. Finally, high doses of vitamin C can boost antimicrobial defenses. Among 24 patients randomized to receive vitamin C (50 to 200 mg·kg-1·d-1) or placebo, no adverse safety events were observed in patients receiving vitamin C infusion. Compared with the placebo group, the SOFA score of patients in the vitamin C group decreased rapidly, and the inflammatory biomarkers (CRP and procalcitonin) were significantly reduced [81]. Recently, Marik et al [82] proposed that taking large doses of vitamin C, thiamine and hydrocortisone can reduce mortality and prevent the occurrence of multiple organ failure in severe sepsis and septic shock. In fact, under the acidotic conditions of sepsis, vitamin C promotes the dissolution of microthrombi in capillaries, thus helping to improve microcirculation.
Recommendation 30: Providing micronutrients is an important part of nutritional therapy. When critically ill neurosurgery patients undergo parenteral nutrition, micronutrients (ie, trace elements and vitamins) should be added separately every day.
Recommendation 31: Antioxidant micronutrients require higher doses when used as antioxidants and should not be used routinely until serious deficiency is proven.
(2) Vitamin D
As long as there is sunlight exposure and good liver and kidney function, the human body can synthesize sufficient amounts of vitamin D3. Critically ill patients are exposed to sunlight for a long time and are often accompanied by abnormal liver and kidney function. Therefore, they will suffer from recurring vitamin D deficiency, which is associated with poor prognosis, including increased mortality, prolonged hospitalization, higher incidence of sepsis, and the need for more intensive care. Long mechanical ventilation time, etc. [83].
It has been confirmed that critically ill patients cannot correct low plasma concentrations of vitamin D simply by relying on nutritional doses and require loading therapy [84]. Based on body weight and initial levels, it is safe to give a high dose at one time in the first week.
The meta-analysis on vitamin D included 7 randomized trials with a total of 716 severely ill adult patients. The trial doses ranged from 200,000 to 540,000 units of vitamin D3. Compared with placebo, patients who supplemented with vitamin D3 had a lower mortality rate and a lower mortality rate. No adverse reactions were observed during the 6-month follow-up [85].
Recommendation 32: Severe neurosurgery patients with proven vitamin D deficiency (25-hydroxyvitamin D <12.5 ng/ml or 50 nmol/L) need vitamin D3 supplementation. During treatment, it is recommended to give a loading dose (single dose of 50 000 to 600 000). unit of vitamin D3) followed by nutritional dose (DRI 600 units) treatment.
(3) Glutamine
GLN is a normal component of protein, accounting for approximately 8% of all amino acids. It mainly plays the role of transporting nitrogen between cells and/or organs, and serves as a raw material for rapid cell proliferation. Under physiological conditions, the human body can maintain adequate GLN levels through daily nutritional intake and endogenous synthesis (skeletal muscle and liver). GLN is generally included in standard enteral nutrition preparations, but is not included in standard parenteral nutrition solutions for stability reasons.
There is currently no direct research support for GLN levels and prognosis in critically ill neurosurgery patients. In other studies of critically ill patients, Rodas et al. [86] showed that there is a U-shaped association between plasma GLN levels and prognosis. Low plasma GLN levels in critically ill patients are associated with poor prognosis. Multiple randomized trials have confirmed that in burn and trauma patients, if plasma GLN levels are low, additional supplementation of GLN can reduce the occurrence of infectious complications and promote wound healing [87, 88].
However, not all critically ill patients are GLN deficient.
Recommendation 33: Critically ill neurosurgery patients do not need to supplement GLN when their enteral nutritional therapy protein reaches the target; patients with severe craniocerebral trauma may consider supplementing GLN when their plasma GLN levels decrease; for patients using standard total parenteral nutrition, Pay attention to supplement GLN. For patients with liver and kidney failure, additional supplementation of GLN is not recommended.
(End of chapter)
