Study drugs and administrative protocol (take a 60 kg patient as an example)
| Group | Concentration | Loading dose | Maintenance dose |
| S-ketamine | 1 mg/mL | 0.25 mg/kg | 0.1 mg/kg/hour |
| ie, the administrative protocol of a 60 kg patient will be a loading dose of 15 mL and a maintenance dose of 6 mL/hour | |||
| Dexmedetomidine | 2 µg/mL | 0.2 µg/kg | 0.2 µg/kg/hour |
| ie, the administrative protocol of a 60 kg patient will be a loading dose of 15 mL and a maintenance dose of 6 mL/hour | |||
| Control | Normal saline | — | — |
| ie, the administrative protocol of a 60 kg patient will be a loading dose of 15 mL and a maintenance dose of 6 mL/hour | |||