Cheatham Michael L, Safcsak Karen, Brzezinski Stacy J, Lube Matthew W
Department of Surgical Education, Orlando Regional Medical Center, Orlando, FL, USA.
Crit Care Med. 2007 Jan;35(1):127-31. doi: 10.1097/01.CCM.0000250390.49380.94.
Goal-directed nutritional support is essential to improving morbidity and mortality. Open abdominal decompression is similarly crucial to the successful treatment of intra-abdominal hypertension and abdominal compartment syndrome. The open abdomen, however, places the patient at risk for potentially significant fluid, electrolyte, and presumably protein losses from the exposed viscera. Although nutritional protein assessments are frequently utilized to measure urinary nitrogen, these calculations do not consider the loss of protein from the open abdomen. We hypothesize that accurate assessment of nitrogen balance in the patient requiring an open abdomen must include either a measurement or estimation of abdominal fluid nitrogen loss.
Prospective, observational cohort study.
Adult surgical/trauma intensive care unit of a level I trauma center.
Surgical/trauma patients requiring laparotomy.
Serial 24-hr collections of urine and abdominal fluid protein were performed to characterize abdominal fluid protein loss and evaluate the clinical effect of accounting for abdominal fluid nitrogen as part of nitrogen balance calculations.
Nitrogen intake correlates with urinary nitrogen loss but not with abdominal fluid nitrogen loss. Abdominal fluid nitrogen loss is significant and remains relatively stable in the early postoperative period. Nutritional calculations that fail to account for abdominal fluid nitrogen loss significantly overestimate actual nitrogen balance by an average of 3.5 g/24 hrs.
The open abdomen represents a significant source of protein/nitrogen loss in the critically ill. Failure to account for this loss in nutritional calculations may lead to underfeeding and inadequate nutritional support with a direct effect on patient outcome. Although direct measurement of abdominal fluid protein loss may be optimal, an estimate of 2 g of nitrogen per liter of abdominal fluid output should be included in the nitrogen balance calculations of any patient with an open abdomen.
目标导向的营养支持对于降低发病率和死亡率至关重要。开放性腹部减压对于成功治疗腹腔内高压和腹腔间隔室综合征同样关键。然而，开放性腹部会使患者面临因暴露内脏而导致大量液体、电解质以及可能的蛋白质流失的风险。尽管营养蛋白评估经常用于测量尿氮，但这些计算并未考虑开放性腹部的蛋白质流失。我们假设，对于需要开放性腹部手术的患者，准确评估氮平衡必须包括测量或估算腹腔液体氮流失。
前瞻性观察性队列研究。
一级创伤中心的成人外科/创伤重症监护病房。
需要剖腹手术的外科/创伤患者。
连续24小时收集尿液和腹腔液体蛋白，以确定腹腔液体蛋白流失情况，并评估将腹腔液体氮作为氮平衡计算一部分的临床效果。
氮摄入量与尿氮流失相关，但与腹腔液体氮流失无关。腹腔液体氮流失量很大，且在术后早期保持相对稳定。未考虑腹腔液体氮流失的营养计算会显著高估实际氮平衡，平均高估3.5克/24小时。
开放性腹部是危重症患者蛋白质/氮流失的重要来源。在营养计算中未考虑这种流失可能导致喂养不足和营养支持不充分，直接影响患者预后。虽然直接测量腹腔液体蛋白流失可能是最佳方法，但在任何开放性腹部患者的氮平衡计算中，应包括每升腹腔液体输出量估计2克氮的估算值。
