Objective Sedation is necessary for patients to achieve comfort and safety, but prolonged sedation can lead to the need for increased doses, resulting in withdrawal syndrome and delayed extubation. Inhaled anaesthetics (IAs) may cause less withdrawal syndrome while providing similar sedative effects to intravenous agents. This study aims to describe the efficacy of halogenated IAs during prolonged sedation and identify any adverse effects on the PICU. Design This is a retrospective, bicentric cohort study. Setting The study was conducted at two PICUs in university hospitals in Paris between January 2018 and December 2020. Patients The study included 50 children (aged 2.2 years, [0.8-7.2]) who received prolonged sedation (> 72 h) and were sedated with volatile anaesthetics for at least 24 h. Interventions No interventions were performed. Measurements and main results The study found a statistically significant reduction in benzodiazepine dosages (μg/kg/h) (118 [62.5; 200] vs 80.0 [32.5; 120], p < 0.01). Similar results were observed for other hypnotics (ketamine 2.00 [1.00; 2.00] vs 1.50 [1.00; 2.00], p = 0.036, mg/kg/h; clonidine: 0.55 [0.35; 1.27] vs 0.20 [0.12; 0.43], p = 0.036, μg/ kg/h). For opioids (μg/kg/h), no significant reduction in doses was observed 24 h after IA introduction (4 [1.00; 8.00] vs 4.00 [1.00; 6.70], p = 0.7). No major adverse effects were reported, although 26% of patients developed withdrawal syndrome. Conclusions Halogenated IAs appear to be a promising therapy to reduce the dosages of hypnotics and opioids used during prolonged sedations.