Controlled hypotension is an effective means of decreasing blood loss and of providing a better visible surgical field. Numerous drugs have been developed to lower arterial blood pressure. The ideal hypotensive drug must be effective in reducing blood pressure and at the same time controllable without any undesirable effect to vital organs. Adenosine triphosphate (ATP), a well known intracellular high energy compound, has been reported to be a hypotensive agent similar in effect to sodium nitroprusside (SNP), a drug which is frequently used as a hypotensive agent.
To investigate the possibility of clinical use of ATP, we compared the cardiovascular effects of SNP- and ATP-induced hypotension and effects on acid-base balance and blood gas content.
The following results were obtained.
1. Controlled hypotension by ATP was stable and rapidly reversible without tachyphylaxis and re-bound hypertension.
2. The heart rate, central venous pressure, pulmonary capillary wedge pressure and pulmonary vascular resistance were unchanged during the SNP- and ATP-induced hypotension. However, hypotension produced by ATP was associated with a greater cardiac output than that induced
by SNP (p<0.01) and was also associated with a further decrease in systemic vascular resistance (p<0.01). Left and right ventricular stroke works were more improved during ATP-induced hypotension than those of SNP. The ratepressure product and coronary perfusion, pressure were decreased in both groups (p<0.01). The mean pulmonary arterial pressure was increased with ATP (p<0.05). Triple index, which is the product of heart rate, systolic blood pressure, and pulmonary wedge pressure, decreased in SNP group (p<0.05).
3. Bicarbonate and base excess in venous blood were decreased with ATP group (p<0.05).
On the basis of this study, compared with SNP, ATP as a hypotensive agent also provide a effective cardiovascular function during controlled hypotension. Therefore, ATP is probably a useful agent for controlled hypotension in a clinical practice.
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