Effects of dexmedetomidine on smooth emergence from anaesthesia in elderly patients undergoing orthopaedic surgery

Abstract

Background: Intraoperative dexmedetomidine may decrease postoperative emergence agitation in elderly patients due to its sedative effect. In this study, we evaluated the effect of adjuvant dexmedetomidine on smooth emergence from anaesthesia after orthopaedic surgery in elderly patients.

Methods: A total 115 patients (ASA I-II, aged over 65 years) were randomly allocated into four groups. Anaesthesia was maintained with either sevoflurane or total intravenous anaesthesia (TIVA) comprising propofol and remifentanil. Patients were also administered either dexmedetomidine (0.4 μg kg(-1) hr(-1); SD and TD) intraoperatively or normal saline (SN or TN) as a control. The bispectral index (BIS) score was maintained from 40-60 intraoperatively. All anaesthetics and dexmedetomidine were discontinued at surgical conclusion, and the recovery times (durations to a BIS = 60, 70, and 80; eye opening; and extubation) were measured. The mean arterial pressure, heart rate, Ricker's agitation-sedation scale (RSAS), visual analogue scale (VAS) for pain, and incidences of emergence agitation and postoperative nausea and vomiting (PONV) were measured in the recovery room.

Results: Dexmedetomidine significantly decreased the RSAS score in the SD and TD groups, and a calm state postoperatively occurred more frequently in these groups than in the control groups. The heart rate and incidence of emergence agitation were lower in the dexmedetomidine groups. Recovery time was higher in the SD group than in the SN group, and no significant differences occurred between the TN and TD groups. The VAS score was lower in the SD group than in the SN group, and the PONV did not differ regardless of the use of dexmedetomidine.

Conclusions: Dexmedetomidine may be an effective intraoperative adjuvant for a reducing emergence agitation and smooth emergence from anaesthesia after orthopaedic surgery in elderly patients.

Trial registration: Current Controlled Trials NCT01851005 .

Fig. 1

Consort flow diagram for the study. Group SN, inhalation anaesthesia using sevoflurane and normal saline administered as a control; Group SD, inhalation anaesthesia using sevoflurane and adjuvant dexmedetomidine; Group TN, TIVA using propofol and remifentanil and normal saline administered as a control; Group TD, TIVA using propofol and remifentanil, and adjuvant dexmedetomidine

Fig. 2

End-tidal concentration of sevoflurane (a), the effect site concentration of propofol (b), and the effect site concentration of remifentanil (c) during anaesthesia. Group SN, inhalation anaesthesia using sevoflurane and normal saline administered as a control; Group SD, inhalation anaesthesia using sevoflurane and adjuvant dexmedetomidine; Group TN, TIVA using propofol and remifentanil and normal saline administered as a control; Group TD, TIVA using propofol and remifentanil, and adjuvant dexmedetomidine; TIVA, total intravenous anaesthesia; Ce, effect site concentration. *P < 0.05 compared with the control group

Fig. 3

Recovery times following orthopaedic surgery. Group SN, inhalation anaesthesia using sevoflurane and normal saline administered as a control; Group SD, inhalation anaesthesia using sevoflurane and adjuvant dexmedetomidine; Group TN, TIVA using propofol and remifentanil and normal saline administered as a control; Group TD, TIVA using propofol and remifentanil, and adjuvant dexmedetomidine; TIVA, total intravenous anaesthesia; BIS, bispectral index. *P < 0.05 compared with SN

Fig. 4

Incidence of emergence agitation and dangerous emergence agitation in the recovery room 30 min after arrival. Group SN, inhalation anaesthesia using sevoflurane and normal saline administered as a control; Group SD, inhalation anaesthesia using sevoflurane and adjuvant dexmedetomidine; Group TN, TIVA using propofol and remifentanil and normal saline administered as a control; Group TD, TIVA using propofol and remifentanil, and adjuvant dexmedetomidine; TIVA, total intravenous administration; EA, emergence agitation. Emergence agitation was defined as a Riker’s sedation-agitation scale greater than 5, and dangerous EA was defined as a score greater than 7

Fig. 5

Hemodynamic changes during infusion of adjuvant drugs and during anaesthetic emergence. a Mean arterial pressure and (b) heart rate measured. Pre-infusion, before infusion of adjuvant drugs; In-10 min, 10 min after infusion of adjuvant drugs; In-30 min, 30 min after infusion of adjuvant drugs; RR, at arrival to recovery room;, RR-15 min, 15 min after arrival to recovery room; RR-30 min, 30 min after arrival to recovery room. Group SN, inhalation anaesthesia using sevoflurane and normal saline administered as a control; Group SD, inhalation anaesthesia using sevoflurane and adjuvant dexmedetomidine; Group TN, TIVA using propofol and remifentanil and normal saline administered as a control; Group TD, TIVA using propofol and remifentanil, and adjuvant dexmedetomidine. *P < 0.05 compared with the SN group. †P < 0.05 compared with the TN group