Wilmore D W, Long J M, Mason A D, Skreen R W, Pruitt B A
Ann Surg. 1974 Oct;180(4):653-69. doi: 10.1097/00000658-197410000-00031.
Hypermetabolism characterizes the metabolic response to thermal injury and the extent of energy production is positively related to the rate of urinary catecholamine excretion. Alpha and beta adrenergic blockade decreased metabolism from 69.6 +/- 5.3 Kcal/m(2)/hr to 57.4 +/- 5.2 (p < 0.01), and infusion of 6 microgm epinephrine/minute in normal man significantly increased metabolic rate. Twenty noninfected burned adults with a mean burn size of 45% total body surface (range 7-84%) and four normal controls were studied in an environmental chamber at two or more temperatures between 19 and 33 C with vapor pressure constant at 11.88 mm Hg. All burn patients were hypermetabolic at all temperatures studied and their core and mean skin temperatures were significantly elevated above control values. Between 25 and 33 C ambient, metabolism was unchanged in controls and burns of less than 40% total body surface (48.9 +/- 4.6 Kcal/m(2)/hr vs. 48.9 +/- 4.5), but metabolic rate decreased in larger burns in the warmer environment (72.0 +/- 1.9 vs. 65.8 +/- 1.7, p < 0.001). At 21 C, metabolism and catecholamines increased, except in four nonsurvivors who became hypothermic with decreased catechol elaboration. Metabolic rate in ten patients with bacteremia was below predicted levels while catecholamines were markedly elevated suggesting interference with tissue uptake of the neurohormonal transmitters. Feeding burn patients or administering glucose and insulin improved nitrogen retention and altered substrate flow but did not significantly reduce urinary catecholamines or metabolic rate. Burned patients are internally warm, not externally cold, and catecholamines appear to mediate their increased heat production. Hypermetabolism may be modified by ambient temperature, infection, and pharmacologic means. Alterations in hypothalamic function due to injury, resulting in increased catecholamine elaboration, would explain the metabolic response to thermal injury.
高代谢是热损伤代谢反应的特征，能量产生的程度与尿儿茶酚胺排泄率呈正相关。α和β肾上腺素能阻断使代谢率从69.6±5.3千卡/平方米/小时降至57.4±5.2（p<0.01），而在正常人中每分钟输注6微克肾上腺素可显著提高代谢率。对20名平均烧伤面积为45%体表面积（范围7 - 84%）的未感染烧伤成年人及4名正常对照者在环境舱中进行研究，温度在19至33摄氏度之间的两个或更多温度点，水汽压恒定在11.88毫米汞柱。所有烧伤患者在研究的所有温度下均处于高代谢状态，其核心温度和平均皮肤温度显著高于对照值。在25至33摄氏度环境中，对照组和体表面积烧伤小于40%的患者代谢率无变化（48.9±4.6千卡/平方米/小时对48.9±4.5），但在温暖环境中较大面积烧伤患者的代谢率下降（72.0±1.9对65.8±1.7，p<0.001）。在21摄氏度时，代谢率和儿茶酚胺增加，但4名未存活患者体温过低且儿茶酚分泌减少。10名菌血症患者的代谢率低于预测水平，而儿茶酚胺显著升高，提示神经激素递质的组织摄取受到干扰。给烧伤患者喂食或给予葡萄糖和胰岛素可改善氮潴留并改变底物代谢，但未显著降低尿儿茶酚胺或代谢率。烧伤患者体内发热，而非体表发冷，儿茶酚胺似乎介导了其产热增加。高代谢可能受环境温度、感染和药物手段影响。由于损伤导致下丘脑功能改变，引起儿茶酚胺分泌增加，这可以解释热损伤的代谢反应。
