Differential effects of esketamine anesthesia induction on ocular circulation: a randomized controlled study

Objective To investigate the effects of esketamine anesthesia induction on ocular circulation and intracranial pressure.

Methods A total of 60 patients who underwent elective clavicle surgery under general anesthesia at the Affiliated Hospital of Yangzhou University from January to September 2023 were selected as study subjects and randomly divided into group S (n=30) and group C (n=30). Before anesthesia induction, 1.5 mg/kg of propofol was administered intravenously for sedation. Subsequently, group S received 0.5 mg/kg of esketamine, while the control group received an equal volume of normal saline. Color Doppler ultrasound was used to measure the hemodynamic parameters of the ophthalmic artery (OA) and central retinal artery at three time points: 2 minutes after propofol sedation (T1), 5 minutes after tracheal intubation (T2), and before extubation at the end of surgery (T3). These parameters includedpeak systolic velocity (PSV), end-diastolic velocity (EDV), and resistance index (RI). Additionally, the optic nerve sheath diameter (ONSD) was measured.

Results At the T2, the ONSD in the group S was wider than that in the group C, the PSV and EDV at the ophthalmic artery site were higher than those in the group C, and the RI was lower than that in the group C (P < 0.05). At the T2, the ONSD in both groups was wider than that at the T1, the PSV and EDV at the ophthalmic artery and central retinal artery sites were higher than those at the T1, and the RI at the ophthalmic artery site was lower than that at the T1 (P < 0.05). At the T2, the heart rate (HR) and mean arterial pressure (MAP) in the group S were higher than those in the group C (P < 0.05). Compared with the T1, the HR and MAP in the group S at the T2 were elevated (P < 0.05). The dosage of remifentanil in the group S was lower than that in the group C (P < 0.05). There were no statistically significant differences in the dosage of propofol and the incidence of adverse reactions between the two groups (P>0.05).

Conclusion A single intravenous injection of 0.5 mg/kg of esketamine can slightly increase the ONSD but does not affect intracranial pressure. Esketamine has a selective effect on ocular circulation vessels, increasing the blood flow velocity of the ophthalmic artery while having no significant effect on the blood flow of the central retinal artery.