We investigated the potential value of vasodilating therapy in critically ill patients with inappropriately low cardiac output during acute illness. In seven patients with low flow state during septic or postoperative state, sodium nitroprusside (20-100 micrograms/min) was compared with nicergoline (NIC) (0.5 to 2.5 mg/min), a new selective alpha 1-blocking agent with negative chronotropic action. Sodium nitroprusside (NP) decreased arterial pressure (from 90 +/- 5 to 68 +/- 5 mm Hg, p less than 0.01) and pulmonary artery balloon-occluded pressure from 20.3 +/- 3.1 to 15.4 +/- 2.8 mm Hg, p less than 0.01) and increased heart rate (from 110 +/- 11 to 120 +/- 13 beats/min, p less than 0.05) but failed to increase stroke volume (from 24.7 +/- 4.8 to 23.4 +/- 4.4 ml, NS). During NIC administration, a comparable decrease in systemic vascular resistance was associated with a significant increase in stroke volume (from 21.6 +/- 3.3 to 25.6 +/- 3.2 ml/m2, p less than 0.01) and cardiac output (CO) (from 2.4 +/- 0.3 to 2.7 +/- 0.3 L/min/m2, p less than 0.025), whereas the decrease in arterial pressure was less significant (from 91 +/- 8 to 84 +/- 7 mm Hg, p less than 0.05). Because NIC has no positive inotropic action, the most likely mechanism is that a baroreceptor-mediated increase in heart rate with NP was prevented by the negative chronotropic action of NIC. Both drugs adversely affected arterial blood oxygenation. By its unique property to decrease heart rate, NIC could represent a valuable vasodilating agent, especially in acute conditions.
Sepsis remains one of the leading causes of mortality in critically ill patients. Increased insight into the complexities of this disease process has resulted in the targeting of various aspects of the inflammatory response as offering potential therapeutic benefits. There have been encouraging results in the past few years. Some of the tested agents have been shown to improve mortality rates in large randomized controlled trials involving patients with severe sepsis. In this article, we discuss the positive and negative results of trials in this field; some of the possible reasons for the negative results are examined, and directions for the future are suggested.
Cardiac output is the amount of blood the heart pumps in 1 minute, and it is dependent on the heart rate, contractility, preload, and afterload. Understanding of the applicability and practical relevance of each of these four components is important when interpreting cardiac output values. In the present article, we use a simple analogy comparing cardiac output with the speed of a bicycle to help appreciate better the effects of various disease processes and interventions on cardiac output and its four components.