Determination of the Median Effective Dose of Dexmedetomidine for the Prevention of Emergence Agitation in Geriatric Patients Undergoing Major Open Surgery With General Anesthesia: A Prospective, Double-Blinded, Dose-Response Trial

Abstract

Dexmedetomidine can effectively decrease the incidences of emergence agitation (EA) in adult patients, but there are major side effects related to increased dose of dexmedetomidine. The purpose of this study was to determine the median effective dose of dexmedetomidine in the prevention of EA among geriatric patients undergoing major open surgery with general anesthesia. A total of 50 geriatric patients were enrolled in this study. Dexmedetomidine 0.5 μg·kg−1·h−1 continuous intravenous infusion was administered to the first patient. The next dose was increased or decreased by .05 depending on the response of the previous patient, according to the Dixon up-and-down method. An “effective” or “ineffective” response was determined based on the Riker sedation-agitation score (RSAS), we defined “effective” as RSAS<5, and “ineffective” as RSAS≥5. The ED50 of dexmedetomidine in prevention of EA was .30 μg·kg−1·h−1 (95% CI, .27–.33) and the predicted ED95 was .42 μg·kg−1·h−1 (95% CI, .38–.51). The incidence of bradycardia was significantly increased in the group without EA compared to the group with EA (57.1% vs 13.6%, P = .002). The ED50 of dexmedetomidine in prevention of EA was .30 μg·kg−1·h−1 (95% CI, .27–.33) and the predicted ED95 was .42 μg·kg−1·h−1 (95% CI, .38–.51). Bradycardia was the main complication.

The Median Effective Dose of Dexmedetomidine for the Inhibition of Emergence Delirium in Preschool Children Undergoing Tonsillectomy and/or Adenoidectomy: A Retrospective Dose-response Trial

“…The advantage of this method is that a small sample is sufficient, but the disadvantage is that the results are not accurate enough because the sample size at the extreme dose is only 1-3, which leads to serious bias. 24,25 In this study, a large sample of 140 children were included in a wide range of dose groups (7 doses), and thus, the results were less biased and highly reliable.…”

Effects of dexmedetomidine combined with etomidate on postoperative cognitive function in older patients undergoing total intravenous anaesthesia: a randomized, double-blind, controlled trial

“…Emergence agitation (EA) often occurs during the initial 30 - 60 min in recovery from general anesthesia, which was characterized as disorientation, confusion, hallucinations and agitation during emergence from general anesthesia [ 31 ]. The intraoperative administration of low-dose dexmedetomidine could reduce emergence agitation and stabilize perioperative haemodynamics [ 32 ].…”

Effective doses of midazolam oral solution for the prevention of preoperative anxiety in paediatric patients

“…5 Their primary focus for measuring success was sedation score (moderate vs. deep) following drug administration or the behavior exhibited by children during separation. 5,[12][13][14][15][16] Consequently, we defined positive outcomes using three scales: (1) the level of sedation required to achieve at least a moderate degree of separation (modified Ramsay score < 3a), (2) good behavior exhibited by children during separation (PSAS ≤ 2), and (3) successful adaptation to the face mask during inhalational anesthesia (MAS ≤ 2).…”