Chapter 362 358. The aftermath: Restarting the Eastern travel plan

Author: Hao Xifeng

Chapter 362 358. The aftermath: Restarting the Eastern travel plan

【Waiting for change】

(2) Protein targets of nutritional therapy

The high catabolic state after nerve injury is associated with significant proteolysis and muscle loss, resulting in an increased demand for protein. Therefore, it is generally believed that critically ill neurosurgery patients have higher protein requirements than other critically ill patients. However, it is still unclear. It is also unclear what the optimal protein target should be, and the best time to achieve the protein energy target. According to previous recommendations, patients can supplement protein at 1.2~2.0 g·kg-1·d-1 [30], of which more than 50 % should be derived from high-quality protein, and can be obtained through the nitrogen balance formula: nitrogen balance (g/24 h) = protein intake (g/24 h)/6.25-[urea nitrogen in urine (g/24 h)+4 ] be evaluated and require ongoing monitoring. High protein supply is associated with improved nitrogen balance.

Whether high protein supply improves the outcomes of critically ill patients is still controversial. A recent meta-analysis shows that high protein supply may be associated with improved mortality in patients with nutritional risks [31]. Multiple observational studies support that high protein supply can improve the body's protein balance. Reduce the time of mechanical ventilation and higher survival rate [27, 3234]. When the protein supply is >1.3 g·kg-1·d-1, the patient's survival can be significantly improved [22].

However, the results of many studies have shown that high protein supply does not have a significant impact on clinical outcomes. The results of a clinical RCT published in 2021 suggested that patients receiving a higher protein supply [(1.5±0.5) than (1.0±0.5 ) g·kg-1·d-1] showed no difference in clinical outcomes or quadriceps myometrium thickness [35]. A recent multicenter RCT including 120 patients studied high protein Compared with the low-protein enteral nutrition formula (100 g/L vs. 63 g/L), the high-protein formula has a higher protein supply (1.52 g·kg-1·d-1 Ratio 0.99 g·kg-1·d-1, body weight calculated according to IBW), but there is no difference in clinical outcomes (90-day mortality) between the two groups [36]. There are still some large clinical trials such as EFORT (NCT03160547 ) are ongoing, with the purpose of evaluating the impact of high and low protein supply on critically ill patients. It is hoped that the latest trial results can give clinicians more guidance. For non-dialysis patients who already have impaired renal function The protein treatment target value should be analyzed based on the specific condition and decided through multi-disciplinary discussion if necessary.

Recommendation 8: Existing evidence cannot provide recommendations on the optimal protein target and the best time to reach the target. Critically ill neurosurgery patients can set the protein target at 1.2~2.0 g·kg-1·d-1 in the acute phase. .

(3) Carbohydrate and fat targets for nutritional therapy

1. Carbohydrates and glucose: When performing enteral nutrition, carbohydrates are the preferred substrate for energy production. Carbohydrates are generally considered harmless, but high carbohydrates may be the main cause of feeding intolerance. Enteral nutrition Other polysaccharide components in the formula may also cause intolerance in susceptible patients. In neurosurgery patients, the incidence of stress hyperglycemia is high, so it is recommended that the energy supply ratio of carbohydrates does not exceed 60% [37], and carbohydrates Compounds are mostly selected from sources with low glycemic index.

During parenteral nutrition, excess glucose-based energy supply is associated with hyperglycemia, increased CO2 production, increased lipogenesis, increased insulin requirements, and has no advantage in reducing protein consumption. The hyperglycemia associated with glucose-rich parenteral nutrition

Glycemia often requires higher doses of insulin. Therefore, it is recommended that the intravenous glucose dose should not exceed 5 mg·kg-1·min-1 [3839].

2. Fat and venous lipids: Lipid oxidation provides more than half of the energy required by the liver, heart and skeletal muscles. Although some studies have evaluated the optimal sugar/fat ratio from the perspective of improving nitrogen balance, due to severe neurosurgery patients

Changes in lipid metabolism, the optimal total amount of daily lipids required is currently unclear. In addition to the total amount, the enteral nutrition formula (enteral nutrition) needs to be carefully evaluated during enteral nutrition.

The composition of nutritional formula (EF), the fat composition included should limit but not completely exclude omega 6 fatty acids, should provide monounsaturated fatty acids, omega 3 fatty acids, reduce saturated fatty acids and avoid trans fatty acids, essential fatty acids (fatty acid, FA)

Recommended dosage is based on Dietary Reference Intakes.

At the same time, fat absorption in severe patients is impaired, and lipid overload may cause immune suppression and damage lung and liver functions. For intravenous lipids, the upper limit of supply is recommended to be 1 g·kg-1·d-1, and the tolerated dose

The maximum is 1.5 g·kg-1·d-1. The lipid ratio can be adjusted according to blood triglyceride levels and liver function [40].

Recommendation 9: When critically ill neurosurgery patients undergo enteral nutrition, it is recommended that the carbohydrate energy supply ratio does not exceed 60%. The optimal fat intake is not yet clear. It is recommended to adjust based on blood triglyceride levels and liver function. Parenteral

During nutrition, it is recommended that the dosage of glucose should not exceed 5 mg·kg-1·min-1. Intravenous lipids (including non-nutritional lipid sources) should not exceed 1.5 g·kg-1·d-1, and lipids should be avoided.

Quality overload.

[3. Enteral nutrition treatment for critically ill neurosurgery patients]

(1) Timing to start enteral nutrition therapy

ASPEN/SCCM (2016) and the "Expert Consensus on Nutritional Support and Treatment of Critically Ill Patients in China" both recommend starting enteral nutrition within 24 to 48 hours, and enteral nutrition is superior to parenteral nutrition [16,41]. European Parenteral and Enteral Nutrition

Society for Internal Nutrition recommends 48 for patients with traumatic brain injury

Initiate enteral nutrition within hours [42]. The European Society of Critical Care Medicine [43] recommends that although the current multiple RCT studies cannot draw a conclusion whether early enteral nutrition will definitely outweigh the harms, based on expert opinions, for the brain

Enteral nutrition should be initiated early in patients with trauma, ischemic or hemorrhagic stroke, and spinal cord injury.

Situations for delayed enteral nutrition therapy: uncontrolled shock, hypoxemia, severe acidosis, active gastrointestinal bleeding, gastric retention >500 ml/6 h, intestinal ischemia, intestinal obstruction, abdominal compartment syndrome

The initiation of enteral nutrition should be postponed due to symptoms such as symptoms. For patients with severe brain damage who undergo therapeutic mild hypothermia, due to a severe decline in metabolic levels and obvious inhibition of gastrointestinal function by cooling, it is recommended to provide low-dose early enteral nutrition. After rewarming

Gradually increase the amount.

Recommendation 10: For critically ill neurosurgery patients, enteral nutrition therapy should be initiated early (within 24 to 48 hours after admission to the intensive care unit) when hemodynamics are stable.

(2) Formula selection for enteral nutrition therapy

1. Whole protein formula vs. short peptide formula: Based on the results of an international multi-center cross-sectional study, it is shown that critically ill neurosurgery patients are often in a low feeding state, and their daily intake of calories and protein are lower than the prescribed amount. The reasons are as follows:

Enteral nutrition intolerance, impaired gastrointestinal motility, etc. The most common clinical manifestations are diarrhea and gastroparesis, which will affect the absorption of nutrients and lead to insufficient energy and calorie intake. The current ASPEN nutrition guideline recommended standards

The whole protein formula is the preferred dosage form for enteral nutrition［

30]. Short peptide nutritional solution contains short peptides and medium-chain fatty acids, which can improve gastrointestinal tolerance. Especially for patients with gastrointestinal function impairment, short peptide formulas are easier to digest and absorb, and reduce the incidence of diarrhea.

However, the results of a single-center RCT on enteral nutrition therapy for patients with severe craniocerebral trauma also showed that compared with the whole protein formula, the short peptide formula has a higher osmotic pressure and may also cause gastrointestinal intolerance, and both groups

There was no significant difference in the average daily intake of calories and protein between the two groups [44].

2. Diabetic formula compared with standard formula: A survey found that the proportion of severe neurosurgery patients with hyperglycemia can be as high as 60%, regardless of whether they have a history of diabetes. Hyperglycemia is an independent risk factor for serious ICU complications, such as electrolyte imbalance and infection.

, prolonged hospitalization and increased mortality, etc.

Diabetic nutritional formulas are usually low in sugar and high in monounsaturated fatty acids, and the maltose in the standard formula is replaced by starch that is slowly digested. Studies have shown that compared with standard enteral nutrition formulas, diabetic formulas combined with insulin therapy can effectively control severe disease

Blood glucose levels in patients with ischemic stroke [45].

3. Immune-modulating formula compared with standard formula: In the 2016 ASPEN guidelines, based on a small sample study (40 patients), compared with standard enteral nutrition formula, immune-modulating formula (mainly containing arginine, glutamine

, ω-3 fatty acids, etc.) can reduce the incidence of infection in patients with craniocerebral trauma[30]. Rai et al[46] carried out

A prospective RCT of moderately severe TBI patients was randomly assigned to receive enteral nutrition with immune formula and standard formula. The results showed that the inflammatory index (IL-6) of patients in the immune formula group was significantly reduced. At the same time, the antioxidant index (glutathione

peptides) were significantly increased; in addition, the total protein level of patients in the immune formula group was also significantly increased. A study conducted on a variety of neurosurgery critical

In a single-center RCT of the disease, Chao et al.[47] found that compared with the standard enteral nutrition formula, the CD4+T lymphocyte count and CD4+/CD8+ ratio in the peripheral blood of patients in the immune-enhanced enteral nutrition formula group were significantly higher, and the serum CD4+T lymphocyte count and CD8+ ratio were significantly higher.

Interferon-γ was significantly increased, while inflammatory factors such as TNF-α, IL-6, IL-8 and IL-10

The levels were significantly reduced; it can be seen that the immune-enhancing enteral nutrition formula can significantly improve the immune status of critically ill neurosurgery patients. In another retrospective study, Painter et al. [48] found that compared with the standard enteral nutrition formula,

Compared with the above, the immune-enhancing formula can reduce the incidence of bloodstream infection, but there is no significant difference in lung infection and urinary tract infection.

4. Mixed formulas with added dietary fiber: Severe neurosurgery patients usually have poor gastrointestinal function tolerance. When patients have persistent diarrhea, enteral nutrition can be replaced with mixed formulas containing dietary fiber. When choosing dietary fiber additives

, less soluble fiber will

Leading to feeding tube blockage. Fibers with high soluble content do not form a gel when dissolved, such as partially hydrolyzed guar gum, wheat dextrin, inulin or fructooligosaccharides, which greatly reduce the probability of feeding tube blockage. Supplementation of soluble dietary fiber can

Reduce the incidence of clinical diarrhea［49,

50, 51]. Soluble dietary fiber uses intestinal probiotics to produce short-chain fatty acids through fermentation, promotes the growth of intestinal beneficial bacteria, and regulates intestinal microecology.

Recommendation 11: For enteral nutrition treatment of critically ill neurosurgery patients, whole protein nutritional formulations can be selected, and for patients with gastrointestinal function impairment, short peptide formulations can be selected.

Recommendation 12: For patients with diabetes or hyperglycemia, using diabetic enteral nutrition formula can help improve blood sugar control in the acute phase.

Recommendation 13: For patients with a higher risk of infection, immunomodulatory enteral nutrition formula can be used.

Recommendation 14: For critically ill neurosurgery patients with persistent diarrhea, a mixed formula containing dietary fiber may be considered.

(3) Feeding approaches for enteral nutrition therapy

Nasogastric tube feeding can promote normal physiological stimulation of the gastrointestinal tract and is technically simple and easy to implement. However, post-pyloric feeding requires certain experience in tube insertion and may delay the start of enteral nutrition. In addition, a joint effort

Included in 1 of 353 ICUs

An international multi-center observational study of 691 critically ill neurosurgery patients (including cerebral hemorrhage, subarachnoid hemorrhage, craniocerebral trauma, intracranial infection, stroke, epilepsy and neurological tumors, etc.) to evaluate the nutritional effects of transgastric feeding and transintestinal feeding

and the impact on clinical endpoints. The results found that although patients in the gastric feeding group had gastrointestinal

The possibility of interruption of enteral nutrition due to complications is higher, but they are better able to accept adequate caloric feeding; in addition, there is no statistical difference between the two groups of patients in other important clinical endpoints such as mechanical ventilation time and the proportion of patients surviving to hospital discharge.

Scientific significance[52]. Therefore, nasogastric tube feeding is recommended as the preferred way of enteral nutrition.

Post-pyloric feeding can reduce the incidence of pneumonia in people with a high risk of aspiration. However, critically ill neurosurgery patients have a high proportion of consciousness disorder, weak airway protection, and a high proportion of mechanical ventilation, making them a high-risk group for aspiration. A study focused on patients with severe TBI

In the RCT study of enteral nutrition route, patients were randomly divided into transgastric tube feeding and post-pyloric feeding groups. The results of the study found that compared with transgastric tube feeding, post-pyloric feeding can significantly reduce the incidence of pneumonia [

53]. A meta-analysis compared the effects of postpyloric feeding and transgastric feeding on the incidence of pneumonia and other important prognostic endpoints in patients with severe TBI. A total of 325 patients in 5 RCT studies were included, and it was found that compared with transgastric feeding,

Postpyloric feeding can significantly reduce the incidence of aspiration pneumonia and ventilator-associated pneumonia [54]. Therefore, postpyloric feeding is feasible for patients who are intolerant to nasogastric tube feeding and have a high risk of aspiration.

Recommendation 15: Nasogastric tube feeding is the preferred route for enteral nutrition. For patients who are intolerant to nasogastric tube feeding and have a high risk of aspiration, postpyloric feeding is possible in centers with conditions.

(4) Feeding methods for enteral nutrition therapy

Although continuous feeding is different from the intestinal physiological model, continuous feeding causes fewer complications in the gastrointestinal tract and respiratory tract, and can achieve nutritional support goals earlier. Compared with continuous feeding, although intermittent feeding is more in line with physiological characteristics, it can

Promotes protein synthesis, but also increases the risk of high gastric residual volume (GRV), diarrhea and aspiration.

The results of a latest meta-analysis in 2021 that included 14 trials and a total of 1,025 critically ill patients showed that compared with continuous feeding, intermittent feeding leads to feeding intolerance, increases the risk of high GRV, and causes errors when the duration is >1 week.

The risk of aspiration increases [55]. The results of multiple clinical studies have shown that continuous feeding can provide more enteral nutrition, and the probability of gastrointestinal intolerance and feeding interruption is smaller [56, 57, 58].

Recommendation 16: It is recommended for critically ill neurosurgery patients to use continuous pumping for enteral nutrition.
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