Suchner U, Katz D P, Fürst P, Beck K, Felbinger T W, Senftleben U, Thiel M, Goetz A E, Peter K
Department of Anesthesiology, Ludwig-Maximilians-University, Munich, Germany.
Crit Care Med. 2001 Aug;29(8):1569-74. doi: 10.1097/00003246-200108000-00012.
To investigate whether rapid or slowly infused intravenous fat emulsions affect the ratio of prostaglandin I2/thromboxane A2 in arterial blood, pulmonary hemodynamics, and gas exchange.
Prospective, controlled, randomized, crossover study.
Operative intensive care unit of a university hospital.
Eighteen critically ill patients. Ten patients were stratified with severe sepsis, and eight patients had acute respiratory distress syndrome (ARDS).
Patients were assigned randomly to receive intravenous fat emulsions (0.4 x resting energy expenditure) over 6 hrs (rapid fat infusion) or 24 hrs (slow fat infusion) along with a routine parenteral nutrition regimen, by using a crossover study design.
Systemic and pulmonary hemodynamics as well as gas exchange measurements were recorded via respective indwelling catheters. Arterial thromboxane B2 and 6-keto-prostaglandin-F1alpha plasma concentrations were obtained by radioimmunoassay, and 6-keto-prostaglandin-F1alpha/thromboxane B2 ratios (P/T ratios) were calculated. Data were collected immediately before and 6, 12, 18, and 24 hrs after onset of fat infusion. In the ARDS group, P/T ratio increased by rapid fat infusion. Concomitantly, pulmonary shunt fraction, alveolar-arterial oxygen tension difference [P(a-a)o2]/Pao2, and cardiac index increased as well, whereas pulmonary vascular resistance and Pao2/Fio2 declined. After slow fat infusion, a decreased P/T ratio was revealed. This was accompanied by decreased pulmonary shunt fraction, lowered P(a-a)o2/Pao2, and increased Pao2/Fio2. Correlations between plasma concentrations of 6-keto-prostaglandin-F1alpha or thromboxane B2 and measures of respiratory performance could be shown during rapid and slow fat infusion, respectively. In the sepsis group, the P/T ratio remained unchanged at either infusion rate, but pulmonary shunt fraction and P(a-a)o2/Pao2 decreased after rapid fat infusion, whereas Pao2/Fio2 increased.
Pulmonary hemodynamics and gas exchange are related to changes of arterial prostanoid levels in ARDS patients, depending on the rate of fat infusion. In ARDS but not in sepsis patients clear of pulmonary organ failure, a changing balance of prostaglandin I2 and thromboxane A2 may modulate gas exchange, presumably via interference with hypoxic pulmonary vasoconstriction.
研究快速或缓慢静脉输注脂肪乳剂是否会影响动脉血中前列腺素I2/血栓素A2的比例、肺血流动力学和气体交换。
前瞻性、对照、随机、交叉研究。
大学医院的手术重症监护病房。
18例危重症患者。10例患者为严重脓毒症，8例患者患有急性呼吸窘迫综合征（ARDS）。
采用交叉研究设计，患者被随机分配接受静脉脂肪乳剂（0.4×静息能量消耗），在6小时内（快速脂肪输注）或24小时内（缓慢脂肪输注），同时采用常规肠外营养方案。
通过各自的留置导管记录全身和肺血流动力学以及气体交换测量值。通过放射免疫分析法测定动脉血栓素B2和6-酮-前列腺素-F1α血浆浓度，并计算6-酮-前列腺素-F1α/血栓素B2比值（P/T比值）。在脂肪输注开始前以及开始后6、12、18和24小时收集数据。在ARDS组中，快速脂肪输注使P/T比值升高。同时，肺分流分数、肺泡-动脉氧分压差[P(a-a)o2]/Pao2和心脏指数也升高，而肺血管阻力和Pao2/Fio2下降。缓慢脂肪输注后，P/T比值降低。这伴随着肺分流分数降低、P(a-a)o2/Pao2降低和Pao2/Fio2升高。在快速和缓慢脂肪输注过程中，分别显示出6-酮-前列腺素-F1α或血栓素B2的血浆浓度与呼吸功能指标之间的相关性。在脓毒症组中，无论输注速度如何，P/T比值均保持不变，但快速脂肪输注后肺分流分数和P(a-a)o2/Pao2降低，而Pao2/Fio2升高。
在ARDS患者中，肺血流动力学和气体交换与动脉类前列腺素水平的变化有关，这取决于脂肪输注的速度。在ARDS患者而非无肺器官衰竭的脓毒症患者中，前列腺素I2和血栓素A2平衡状态的改变可能通过干扰低氧性肺血管收缩来调节气体交换。
