Blinding and randomisation
The anaesthesia was administered by an anaesthesiologist who was blinded to the patient grouping, and the postoperative assessment was conducted by a researcher who was also blinded to the patient grouping. All patients received a combination of inhalation and intravenous therapy. In both groups, the study drug, 0.5 mg penehyclidine, was diluted and mixed with 5 mL of normal saline. In group A, patients inhaled penehyclidine with a fraction of inspired oxygen (FiOAn independent investigator generated a computer-based randomisation list. The participants were randomly assigned to the inhalation or intravenous group in a 1:1 ratio using a computer-generated random sequence. The randomisation process involved sealed, sequentially numbered, and opaque envelopes that were kept in the operating room.