Autonomic and cardiovascular effects of pentobarbital anesthesia during trigeminal stimulation in cats

Abstract

Stimulation of the trigeminal nerve can elicit various cardiovascular and autonomic responses; however, the effects of anesthesia with pentobarbital sodium on these responses are unclear. Pentobarbital sodium was infused intravenously at a nominal rate and the lingual nerve was electrically stimulated at each infusion rate. Increases in systolic blood pressure (SBP) and heart rate (HR) were evoked by lingual nerve stimulation at an infusion rate between 5 and 7 mg·kg−1·h−1. This response was associated with an increase in the low-frequency band of SBP variability (SBP-LF). As the infusion rate increased to 10 mg·kg−1·h−1 or more, decreases in SBP and HR were observed. This response was associated with the reduction of SBP-LF. In conclusion, lingual nerve stimulation has both sympathomimetic and sympathoinhibitory effects, depending on the depth of pentobarbital anesthesia. The reaction pattern seems to be closely related to the autonomic balance produced by pentobarbital anesthesia.

Antagonistic and Synergistic Activation of Cardiovascular Vagal and Sympathetic Motor Outflows in Trigeminal Reflexes

“…The second aspect to consider is the administration of different analgesics and anesthetics that may modulate the trigeminal–vagal reflexes in variable and unpredictable ways ( 26 – 29 ). This is of particular importance for the trigeminocardiac reflex, since numerous studies reported autonomic reaction differences based on the use of these drugs ( 30 ). Therefore, anesthesia type and depth are important factors to consider in the clinical management of patients undergoing surgical interventions in the trigeminal territory who are at potential risk of cardiovascular depression ( 31 – 33 ).…”

The Trigeminal Nerve and the Heart

“…25 The TCR occurs less frequently with sevoflurane than with halothane. Sometimes these reflexes are depressed, and sometimes they are exacerbated.…”

“…19,26 Ketamine was associated with a decrease in the incidence of the OCR compared with propofol. 25 During light pentobarbital anesthesia, lingual nerve stimulation has sympathomimetic effects, whereas it has sympathoinhibitory effects during moderate anesthesia, leading to TDR. [29][30][31] The depth of anesthesia has demonstrated to be a conditioning factor in arterial pressure responses in TCR.…”

Isolated Bradycardia Due to Skull Pin Fixation

“…3 However, the general practice involves augmenting the depth of anesthesia to reduce the tachycardia and hypertension produced during skull pin fixation. We agree that trigemino cardiac reflex (TCR) may occur during skull pin fixation in neuro-surgery.…”