Can donepezil facilitate weaning from mechanical ventilation in difficult to wean patients? An interventional pilot study

Background: Management of difficult to wean patients is a dilemma for health care system. Recently published studies demonstrated efficacy of donepezil to counteract respiratory depression in sleep apnea. However, to the best of our knowledge, pharmaceutical interventions with donepezil to facilitate weaning have not been tested so far. Therefore in the present study, we evaluated the efficacy of using donepezil on weaning course in difficult to wean patients. Methods: In this non-randomized interventional clinical study, difficult to wean patients with prior inappropriately depressed respiratory responses were included from two referral intensive care units (ICU) in Iran. Patients with another potentially reasons of weaning failure were excluded from the study. Donepezil was started for eligible patients at dose of 10 mg daily for 2–4 weeks. For the primary outcomes, arterial blood gas (ABG) parameters were also measured before and after intervention to evaluate the possible effects of donepezil on them. In addition, weaning outcomes of patients were reported as final outcome in response to this intervention. Results: Twelve out of 16 studied patients experienced successful results to facilitate weaning with donepezil intervention. The mean duration of donepezil treatment until outcome measurement was 12 days. There were not any significant differences in ABG parameters among patients with successful and failed weaning trial on day of donepezil initiation. However after donepezil intervention, mean of PCO2 and HCO3 decreased in patients with successful weaning trial and mean of PCO2 increased in those with weaning failure. Conclusions: Reduced central respiratory drive was infrequently reason of failed weaning attempts but it must be considered especially in patients with hypercapnia secondary to inefficient gas exchange and slow breathing. Our results in the clinical setting suggest that, the use of donepezil can expedite weaning presumably by stimulation of respiratory center and obviate the need to re-intubation in cases of respiratory drive problem in difficult to wean patients. We suggest decrease PCO2 and HCO3 during donepezil steady could be valuable predictors for positive response to donepezil intervention.