Hayes M A, Timmins A C, Yau E H, Palazzo M, Hinds C J, Watson D
Department of Anesthesia, St. Bartholomew's Hospital, Smithfield, London, United Kingdom.
N Engl J Med. 1994 Jun 16;330(24):1717-22. doi: 10.1056/NEJM199406163302404.
Elevation of systemic oxygen delivery and consumption has been associated with an improved outcome in critically ill patients. We conducted a randomized trial to determine whether boosting oxygen delivery by infusing the inotropic agent dobutamine would improve the outcome in a diverse group of such patients.
On the basis of previously published recommendations, we established the following goals: a cardiac index above 4.5 liters per minute per square meter of body-surface area, oxygen delivery above 600 ml per minute per square meter, and oxygen consumption above 170 ml per minute per square meter. If these goals were not achieved with volume expansion alone, patients were randomly assigned to a treatment or control group. The treatment group received intravenous dobutamine (5 to 200 micrograms per kilogram of body weight per minute) until all three goals had been achieved. Dobutamine was administered to the control group only if the cardiac index was below 2.8 liters per minute per square meter.
A total of 109 patients were studied. In nine patients the therapeutic goals were achieved with volume expansion alone; all nine patients survived to leave the hospital. Fifty patients were randomly assigned to the treatment group, and 50 to the control group. During treatment, there were no differences between the two groups in mean arterial pressure or oxygen consumption, despite a significantly higher cardiac index and level of oxygen delivery in the treatment group (P < 0.05). Although the predicted risk of death during hospitalization was 34 percent for both groups, the in-hospital mortality was lower in the control group (34 percent) than in the treatment group (54 percent) (P = 0.04; 95 percent confidence interval, 0.9 to 39.1 percent).
The use of dobutamine to boost the cardiac index and systemic oxygen delivery failed to improve the outcome in this heterogeneous group of critically ill patients. Contrary to what might have been expected, our results suggest that in some cases aggressive efforts to increase oxygen consumption may have been detrimental.
全身氧输送和氧消耗的增加与危重症患者预后改善相关。我们进行了一项随机试验，以确定通过输注正性肌力药物多巴酚丁胺提高氧输送是否能改善这类不同患者群体的预后。
根据先前发表的建议，我们设定了以下目标：心脏指数高于4.5升/分钟/每平方米体表面积，氧输送高于600毫升/分钟/每平方米，氧消耗高于170毫升/分钟/每平方米。如果仅通过扩容未达到这些目标，患者被随机分配到治疗组或对照组。治疗组接受静脉注射多巴酚丁胺（5至200微克/千克体重/分钟），直至所有三个目标均实现。仅当心脏指数低于2.8升/分钟/每平方米时，才给对照组使用多巴酚丁胺。
共研究了109例患者。9例患者仅通过扩容就实现了治疗目标；所有9例患者均存活出院。50例患者被随机分配到治疗组，50例被分配到对照组。治疗期间，两组的平均动脉压或氧消耗无差异，尽管治疗组的心脏指数和氧输送水平显著更高（P<0.05）。虽然两组住院期间预测的死亡风险均为34%，但对照组的院内死亡率（34%）低于治疗组（54%）（P=0.04；95%置信区间，0.9至39.1%）。
使用多巴酚丁胺提高心脏指数和全身氧输送未能改善这类异质性危重症患者的预后。与预期相反，我们的结果表明，在某些情况下，积极努力增加氧消耗可能是有害的。
