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. 2019 Nov 21;2019(11):CD011931. doi: 10.1002/14651858.CD011931.pub2

Yun 2016.

Methods Study design: randomized controlled trial (3 arms)
Study duration: not reported
Study setting: hospital, single centre, China
Participants Adults undergoing elective supratentorial craniotomy (n = 150)
Inclusion criteria

  1. ASA I to ASA II participants undergoing above surgery


Exclusion criteria

  1. GCS < 15

  2. Bradycardia: HR < 50

  3. Hypertension: systolic blood pressure > = 180 mmHg or diastolic > / = 110 mmHg

  4. History of lung, liver or kidney disease

  5. Allergy to study drugs

  6. Body weight 15% above or below normal: Brocas index


Mean age, range (years)

  1. 50 (35 to 65)


Numbers allocated to each arm

  1. Group 1: dexmedetomidine infusion 0.4 mcg/kg (n = 50)

  2. Group 2: dexmedetomidine infusion 0.8 mcg/kg (n = 50)

  3. Group 3: control, saline infusion (n = 50)


Male gender

  1. Group 1: 13/45 (patients analysed)

  2. Group 2: 15/43 (patients analysed)

  3. Group 3: 20/46 (patients analysed)
Interventions Technique and timing

  1. Different dosages of dexmedetomidine by intravenous infusion given or a total of 10 minutes, 1 hour before the end of surgery


Group 1: dexmedetomidine infusion 0.4 mcg/kg
Group 2: dexmedetomidine infusion 0.8 mcg/kg
Group 3: control,saline infusion
Dosages
As above
Outcomes Primary

  1. Hypertension on emergence


Secondary

  1. Tachycardia on emergence

  2. Incidience of significant postoperative pain –NRS – numerical rating score > / = 4

  3. Cough after extubation

  4. Adverse event ‐ nausea and vomiting
Notes Funding
None
Risk of bias
Bias Authors' judgement Support for judgement
Random sequence generation (selection bias) Low risk Quote. ''using computer‐generated random numbers and a sealed‐envelop technique, patients were allocated randomly into 1 of 3 groups: small‐dose DEX (0.4 mg/kg), median‐dose DEX (0.8 mg/kg), or vehicle control (an equivalent volume of normal saline)."
Allocation concealment (selection bias) Low risk Sealed envelopes
Blinding of participants and personnel (performance bias) 
 All outcomes Low risk Quote. "the attending anaesthesiologists were unaware of the grouping'', implying that those administering the infusion were unaware of the contents of the syringe''.
Blinding of outcome assessment (detection bias) 
 All outcomes Low risk Quote: ''the attending anaesthesiologists were unaware of the grouping, and the measurements were recorded by 1 nurse, who was also blinded''.
Incomplete outcome data (attrition bias) 
 All outcomes Unclear risk 17 participants were excluded from the final analysis as follows:
8 participants did not receive the allocated intervention.
Group 1: 3 excluded (1 had prolonged surgery and 2 had blood loss > 1400 mL)
Group 2: 2 excluded (1 had a seizure and 1 had blood loss > 1400 mL)
Group 3: 2 excluded (1 had a prolonged surgery and 1 had blood loss > 1400 mL)
9 participants were lost to follow‐up after receiving their allocated intervention.
Group 1: 2 excluded (1 had an intracranial bleed and 1 had a seizure requiring sedation)
Group 2: 5 excluded (1 had a weight < 45 kg, 1 had an intracranial bleed, 1 had prolonged surgery, 1 had delayed recovery and I had an unclear reason)
Group 3: 2 excluded (1 had an intracranial bleed and 1 had a low level of consciousness)
The relatively large numbers excluded and the inequality of both numbers and reasons across groups together with the lack of an intention‐to‐treat analysis, made it difficult to measure the true effect estimate accurately.
Selective reporting (reporting bias) Low risk Outcomes reported as specified
Other bias Unclear risk Small study