pone.0329207.t016 -

Objective
This study aimed to investigate the impact of different energy levels and ingredient ratios on the nasogastric tube patency of pureed diets, optimizing the formulations to meet the nutritional requirements of elderly nasogastric feeding patients while minimizing tube blockage risk.
Methods
The study followed the guidelines of the “Chinese Resident’s Balanced Diet Pyramid” and formulated five different energy levels of pureed diets (900 kcal, 1200 kcal, 1500 kcal, 1800 kcal, and 2100 kcal) using natural food groups. The diets consisted of seven major food categories: cereals and tubers, vegetables, meats, milk, oil, salt, and fruits. The liquid formulations for the above energy levels were prepared according to the concentration standards for special medical purpose foods (FSMPs). The maximum injection force required for nasogastric feeding was measured via a texture analyzer. The nutritional components of the pureed diets at different energy levels and ingredient ratios were evaluated via West China Hospital Nutrition Software. Spearman correlation analysis, multiple regression analysis, and random forest models were used to explore the relationships between energy levels, nutritional components, ingredients, maximum injection force, and tube patency.
Results
The study revealed that as the energy density increased, the maximum injection force of the pureed diets significantly increased (p < 0.05), particularly at the 2100 kcal energy level, where the “rice‒carrot‒beef” formula reached the highest value (117.59 ± 0.26 N), whereas the “FSMP” formula at 900 kcal presented the lowest injection force (9.62 ± 0.20 N). There was a significant difference in the impact of different energy levels and formulations on the maximum injection force (p < 0.05). Spearman correlation analysis indicated that carbohydrate (ρ = 0.736) and dietary fiber (ρ = 0.668) contents were significantly positively correlated with the maximum injection force (p < 0.05). Multiple regression analysis further revealed that carbohydrates were the primary factor influencing the injection force, with a regression coefficient of 0.247 (p < 0.05), suggesting that each additional gram of carbohydrate increased the maximum injection force by approximately 0.247 N, whereas the effects of protein, fat, and dietary fiber were not significant (p > 0.05). All nutritional components (energy (ρ = 0.629), carbohydrates (ρ = 0.621), protein (ρ = 0.582), fat (ρ = 0.547), and dietary fiber (ρ = 0.544)) were significantly positively correlated with tube blockage (p < 0.05). Mann‒Whitney U tests revealed that the energy, carbohydrate, protein, fat, and dietary fiber contents in the tube blockage group were significantly greater than those in the nonblockage group (p < 0.05). With respect to food categories, cereals (ρ = 0.742) and meats (ρ = 0.766) were significantly positively correlated with the maximum injection force (p < 0.05). Specifically, rice (ρ = 0.7886) and sweet potato (ρ = 0.506) were significantly positively correlated (p < 0.05), whereas rice flour (ρ = −0.411) and milk (ρ = −0.690) were significantly negatively correlated (P < 0.05). Moreover, cereals (ρ = 0.615) and meats (ρ = 0.628) were significantly positively correlated with the risk of tube blockage at all energy levels (p < 0.05), with rice (ρ = 0.660) and beef (ρ = 0.153) significantly increasing the risk of blockage, whereas rice flour (ρ = −0.350) and milk (ρ = −0.557) were significantly negatively correlated with the risk of blockage (P < 0.05). The random forest model’s feature importance analysis revealed that carbohydrates (33.33%) and dietary fiber (23.01%) were the most important factors for predicting tube blockage, with an AUC value of 0.91, indicating strong predictive ability.
Conclusion
This study explores the impact of nutritional components and ingredient characteristics on tube patency and blockage risk in nasogastric pureed diets, revealing key optimization pathways for pureed diet formulations. The energy density and ingredient selection of pureed diets significantly affect tube patency. High-energy diets provide higher nutritional density but significantly increase the injection force and blockage risk. Diet formulations should be optimized by reducing high-viscosity and high-hardness ingredients such as rice and beef, using rice flour to replace rice, and milk as the liquid component. For high-energy demands, the carbohydrate and dietary fiber contents should be controlled to reduce the injection force requirements and blockage risk. The study also developed a five-dimensional blockage risk warning model based on energy, protein, fat, carbohydrate, and dietary fiber (AUC = 0.91), classifying low-, medium-, and high-risk levels. Low-risk patients (energy≤1400 kcal/d, carbohydrates≤200 g/d, protein≤70 g/d) are recommended to use homemade formulas, whereas high-risk patients (energy≥1601 kcal/d, carbohydrates≥241 g/d, protein≥86 g/d) should use FSMP for full feeding to balance nutritional supply and tube patency. The findings of this study provide both theoretical and practical guidance for optimizing diets for dysphagia patients, emphasizing that adjusting formulations can effectively balance nutritional supply and tube patency, reduce blockage risk, and prevent malnutrition in homemade pureed feed. This has significant implications for reducing nasogastric complications and ensuring the safety of medical procedures.

研究目的
本研究旨在探究不同能量水平与配料比例对匀浆膳（pureed diets）鼻胃管通畅性（nasogastric tube patency）的影响，优化配方以满足老年鼻胃管喂养患者的营养需求，同时降低堵管风险。

研究方法
本研究遵循《中国居民平衡膳食宝塔》的指导原则，采用天然食材组配制了5种不同能量水平的匀浆膳，能量水平分别为900 kcal、1200 kcal、1500 kcal、1800 kcal及2100 kcal。该膳食包含7大类食材：谷薯类、蔬菜类、肉类、乳类、油脂类、食盐及水果类。上述各能量水平的液体制剂均按照特殊医学用途配方食品（FSMP）的浓度标准制备。通过质构分析仪（texture analyzer）测定鼻胃管喂养所需的最大注射力。采用华西医院营养软件（West China Hospital Nutrition Software）评估不同能量水平及配料比例的匀浆膳的营养成分。运用斯皮尔曼相关性分析（Spearman correlation analysis）、多元回归分析（multiple regression analysis）及随机森林模型（random forest models），探究能量水平、营养成分、配料、最大注射力与鼻胃管通畅性之间的关联。

研究结果
本研究发现，随着能量密度升高，匀浆膳的最大注射力显著升高（p<0.05），其中2100 kcal能量水平下的“大米-胡萝卜-牛肉”配方达到最高值（117.59±0.26 N），而900 kcal能量水平下的特殊医学用途配方食品（FSMP）配方注射力最低（9.62±0.20 N）。不同能量水平与配方对最大注射力的影响存在显著差异（p<0.05）。
斯皮尔曼相关性分析显示，碳水化合物（ρ=0.736）与膳食纤维（ρ=0.668）含量与最大注射力呈显著正相关（p<0.05）。多元回归分析进一步表明，碳水化合物是影响注射力的主要因素，回归系数为0.247（p<0.05），即每增加1g碳水化合物，最大注射力约升高0.247 N；而蛋白质、脂肪及膳食纤维的影响不显著（p>0.05）。
所有营养成分均与堵管风险呈显著正相关：能量（ρ=0.629）、碳水化合物（ρ=0.621）、蛋白质（ρ=0.582）、脂肪（ρ=0.547）及膳食纤维（ρ=0.544）（p<0.05）。曼-惠特尼U检验（Mann‒Whitney U tests）结果显示，堵管组的能量、碳水化合物、蛋白质、脂肪及膳食纤维含量均显著高于非堵管组（p<0.05）。
从食材类别来看，谷薯类（ρ=0.742）与肉类（ρ=0.766）与最大注射力呈显著正相关（p<0.05）。具体而言，大米（ρ=0.7886）与红薯（ρ=0.506）呈显著正相关（p<0.05），而米粉（ρ=-0.411）与乳类（ρ=-0.690）呈显著负相关（p<0.05）。此外，在所有能量水平下，谷薯类（ρ=0.615）与肉类（ρ=0.628）均与堵管风险呈显著正相关（p<0.05）；其中大米（ρ=0.660）与牛肉（ρ=0.153）会显著升高堵管风险，而米粉（ρ=-0.350）与乳类（ρ=-0.557）则与堵管风险呈显著负相关（p<0.05）。
随机森林模型的特征重要性分析显示，碳水化合物（占比33.33%）与膳食纤维（占比23.01%）是预测堵管风险的最重要因素，模型的受试者工作特征曲线下面积（AUC）为0.91，表明其预测能力较强。

研究结论
本研究探究了匀浆膳的营养成分与食材特性对鼻胃管通畅性及堵管风险的影响，揭示了匀浆膳配方的关键优化路径。匀浆膳的能量密度与食材选择对鼻胃管通畅性具有显著影响：高能量膳食虽可提供更高的营养密度，但会显著升高注射力与堵管风险。
配方优化应通过减少大米、牛肉等高黏度、高硬度食材，使用米粉替代大米，并以乳类作为液体成分实现。对于存在高能量需求的患者，应控制碳水化合物与膳食纤维的含量，以降低注射力需求与堵管风险。
本研究还基于能量、蛋白质、脂肪、碳水化合物及膳食纤维构建了五维堵管风险预警模型（AUC=0.91），可将患者划分为低、中、高三个风险等级。建议低风险患者（每日能量≤1400 kcal、碳水化合物≤200g、蛋白质≤70g）采用自制配方；高风险患者（每日能量≥1601 kcal、碳水化合物≥241g、蛋白质≥86g）应使用特殊医学用途配方食品（FSMP）进行全量喂养，以平衡营养供给与鼻胃管通畅性。
本研究结果为吞咽障碍患者的膳食优化提供了理论与实践指导，表明调整配方可有效平衡营养供给与鼻胃管通畅性，降低堵管风险，预防自制匀浆喂养所致的营养不良，对减少鼻胃管并发症、保障医疗操作安全具有重要意义。