Haemodynamic and Cerebral Effects of Atp-Induced Hypotension

Abstract

Controlled decreases in mean arterial pressure to 20%, 40% and 60% of baseline were produced by the administration of increasing concentrations of adenosine triphosphate (ATP) i.v. in five anaesthetized baboons. Indices of the systemic circulation (arterial pressure, right atrial pressure, pulmonary artery pressures, cardiac output) and of the cerebral circulation (cerebral blood flow, cerebral metabolic rate for oxygen, cerebrovascular reactivity) were obtained as arterial pressure was decreased, and following discontinuation of the infusion of ATP. A neuropathological investigation was undertaken at the end of the experimental procedure. The infusion of ATP produced dose-dependent decreases in systemic vascular resistance and mean arterial pressure (MAP). Cardiac output and stroke volume were maintained close to baseline values, or increased slightly. Cerebral blood flow (CBF) increased initially (48 +/- 4 ml min-1/100 g to 68 +/- 9 ml min-1/100 g) and then decreased progressively as MAP was decreased to 40% and 60% of baseline. Cerebrovascular reactivity was shown to be impaired during, and for up to 90 min following, the administration of ATP. However, there was no morphological evidence of ischaemic cell damage in any animal. Tachyphylaxis was not observed during, and there were no instances of rebound hypertension following, the infusion of ATP. The concentration of uric acid had increased significantly by the 40% decrement in MAP, and remained so 60 min after the restoration of the arterial pressure.

Effect of adenosine‐induced hypotension on the cerebral autoregulation in the anesthetized pig

“…In contrast to the unaffected CBF in the post-hypotensive period found in the present study, a cerebral hyperperfusion with increased CBF together with unchanged CPP and CMRo, was demonstrated in our previous study after adenosine-induced hypotension in four out of eight pigs (36). Cerebral posthypotensive hyperperfusion has also been documented in studies on pigs (34), baboons (37) and humans (21). The differences in the posthypotensive CBF response may be related to the different anesthetic techniques.…”

Effect of Propofol on Cerebral Circulation and Autoregulation in the Baboon

“…Angiotensin I1 itself, used to provoke the blood pressure increases, has no effect on CBF unless administered immediately adjacent to a cerebral vessel (21,22). The same autoregulation test, under similar background anesthetic conditions, is capable of detecting disturbed autoregulation with high concentrations of isoflurane and during adenosine triphosphate-induced hypotension (23,24).…”

“…The basic anesthetic technique used in this study, namely phencyclidine, N,O, and succinylcholine, has been previously used for studies on cerebral circulatory effects of drugs, including autoregulation testing (4, [23][24][25]. Because N20, succinylcholine, and phencyclidine were given during the entire experiment, we cannot exclude some influence of these agents on systemic and cerebrovascular hemodynamics.…”

Comprehensive Exploration of Medications That Affect the Bleeding Risk of Oral Anticoagulant Users

“…Telmisartan inhibits digoxin efflux to the intestinal lumen throughaP-gp-inhibitoryeffect. 36) As elimination of rivaroxaban and apixaban, the substrate of P-gp, 3) is inhibited due to their inhibitory effect on P-gp, it is possible that telmisartan would increase the blood levels of these two drugs via P-gpmediated interactions, which may have increased the risk of hemorrhage.…”