Central hemodynamic effects

The effect of baricity on the hemodynamic effects of intrathecal 0.5% bupivacaine has been measured by recording invasive systolic blood pressure and central venous pressure in 36 men given plain bupivacaine 0.5%, heavy bupivacaine 0.5% (in dextrose 8%), or a mixture of the two (in dextrose 4%) (186). Heavy bupivacaine caused more rapid falls in central venous pressure and systolic blood pressure than plain bupivacaine. However, it was subsequently remarked that both 4 and 8% dextrose are significantly hyperbaric relative to adult cerebrospinal fluid, implying that the 4% solution should have behaved more like the 8% solution (187). 

The net hemodynamic effects of calcium inhibitory compounds vary considerably depending upon their diverse pharmacologic activities independent of Ca + inhibition, their dose response characteristics, and their ability to initiate or inhibit central nervous system reflex mechanisms. 

Leier, C. V., Bambach, D., Thompson, M. J., Cattaneo, S. M., Goldberg, R. J., and Unverferth, D. V. (1981a). Central and regional hemodynamic effects of intravenous isosorbide dinitrate, nitroglycerin, and nitroprusside in patients with congestive heart failure. Am. J. Cardiol. 48, 1115-1123. 

Very few animal studies have addressed the question of whether addition of NO to inhaled gas has benefits in addition to improved gas exchange and/or central hemodynamics. Zayek et al. (1993) randomized newborn near-term lambs with experimentally induced persistent pulmonary hypertension by ductus ligation. They compared the effect of prolonged inhalation of 80 ppm NO to that of a control group, with both groups mechanically ventilated postnatally for 23 hr. A significant increase in the survival of lambs by inhaling NO was reported. 

Common adverse events clonidine has a centrally mediated sedative effect. Other CNS depressants, such as benzodiazepines and opioids, may enhance the sedative effects of clonidine. Neuraxial clonidine can also affect the sympathetic nervous system, resulting in hypotension and bradycardia. When clonidine is used as a neuraxial adjunct analgesic, its hemodynamic effects may be enhanced by other neuraxial medications, particularly as local anesthetics. AU effects are dose- dependent. 

O2 transport values and hemodynamics and may increase adverse cardiac effects. Infusion rates should be guided by clinical end points and mixed venous oxygen saturation/central venous oxygen saturation. Decreases in partial pressure of O2, as well as myocardial adverse effects such as tachycardia, ischemic changes on ECG, tachydysrhythmias, and hypotension, are seen. 

Indometacin is used for non-invasive closure of symptomatic ductus arteriosus in the preterm infant. Intravenous administration causes an instant reduction in cerebral blood flow, increasing cerebral vascular resistance. The clinical significance for the nervous system of these hemodynamic changes is unknown (11,12), but they seem to be linked to the effects seen in the central nervous system. Advantage has been taken of this effect for reducing intracranial hypertension in patients with severe head injury (SEDA-15, 99). 

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