BIS-guided sedation prevents the cough reaction of patients under general anaesthesia caused by extubation: a randomized controlled trial

Background The multiple modes of SARS-CoV-2 transmission including airborne, droplet, contact and faecal–oral transmissions that cause coronavirus disease 2019 (COVID-19) contribute to a public threat to the lives of people worldwide. Heavy aerosol production by coughing and the big peak expiratory flow in patients with respiratory infections (especially SARS-CoV-2) during recovery from general anaesthesia are the highest risk factors for infection in healthcare workers. To perform sedation before extubation significantly reduced the incidence of coughing during recovery from general anaesthesia. However, there are few studies on endotracheal tube removal under BIS-guided sedation in postanaesthesia care unit (PACU). We speculated that the BIS-guided sedation with dexmedetomidine and propofol would better prevent coughing caused by tracheal extubation and reducing peak expiratory flow. Methods Patients with general anaesthesia were randomly assigned to Group S (dexmedetomidine was infused in the operating room for 30 min, and the bispectral index (BIS) value was maintained 60–70 by infusion propofol at 0.5~1.5 μg/ml in the PACU until the endotracheal tubes were pulled out) and Group C (no dexmedetomidine and propofol treatment, replaced with the saline treatment). The incidence of coughing, agitation and active extubation, endotracheal tube tolerance and the peak expiratory flow at spontaneous breathing and at extubation were assessed. Results A total of 101 patients were randomly assigned to Group S (51 cases) and Group C (50 cases). The incidence of coughing, agitation and active extubation was significantly lower (1(51), 0(51) and 0(51), respectively) in Group S than (11(50), 8(50) and 5(50), respectively) in Group C ( p < 0.05 or p < 0.01, respectively); the scores of cough were significantly reduced (1(1, 1)) in Group S than (1(1, 2)) in Group C ( p < 0.01); and the endotracheal tube tolerance was significantly improved (0(0, 1)) in Group S than (1(1, 3)) in Group C ( p < 0.001). The peak expiratory flow at spontaneous breathing and at extubation was significantly reduced (5(5, 7) and 6.5(6, 8), respectively) in Group S than (8(5, 10) and 21(9, 32)) in Group C ( p < 0.001). Conclusions BIS-guided sedation with dexmedetomidine and propofol significantly prevented coughing and reduced peak expiratory flow during recovery from general anaesthesia, which may play an important role in preventing medical staff from contracting COVID-19. Trial registration Chinese Clinical Trial Registry: ChiCTR2200058429 (registration date: 09-04-2022) “retrospectively registered”.