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Preoperative Dexmedetomidine & EC50 of Propofol (PreopDXM)

24 mars 2014 uppdaterad av: Hee-Pyoung Park, Seoul National University Hospital

Preoperative Dexmedetomidine Reduces the EC50 of Propofol for Successful i-gelTM Insertion Without Muscle Relaxants

Dexmedetomidine is a useful anaesthetic adjuvant for general anaesthesia. In this prospective randomised study, we determined whether preoperative dexmedetomidine administration could reduce the half maximal effective concentration (EC50) of propofol for successful i-gelTM insertion without muscle relaxants.

Studieöversikt

Detaljerad beskrivning

Propofol is a useful induction agent for LMA insertion without muscle relaxants because it profoundly inhibits pharyngeal and laryngeal reactivity. A previous report showed that the effect-site concentration of propofol for successful classic LMA insertion in 50% of adults (EC50) without muscle relaxants in healthy male patients was 8.72 (0.55) µg ml-1. The EC50 of propofol may be dependent on the type of LMA used. A previous study comparing the EC50 of the propofol concentration between classic and proseal LMA insertions demonstrated that the EC50 of propofol needed for proseal LMA insertion was 35% greater than that needed for classic LMA insertion. Unfortunately, no investigation has been performed to determine the EC50 of the propofol concentration required for i-gel insertion without muscle relaxants.

Dexmedetomidine (DEX), a selective alpha-2 agonist, has sympatholytic, sedative, and analgesic properties. Such beneficial characteristics make DEX a useful anaesthetic adjuvant for general anaesthesia. Many reports have revealed the beneficial effects of DEX in terms of reducing intraoperative anaesthetic requirements, postoperative analgesic demand, and increased haemodynamic responses to noxious stimuli such as endotracheal intubation. A previous investigation showed that preoperative clonidine, an alpha-2 agonist, decreased the EC50 required for LMA insertion.

We hypothesised that preoperative DEX administration can reduce the propofol concentration required for i-gel insertion. In this study, we compared the EC50 of propofol needed for successful i-gel insertion without muscle relaxants between DEX and placebo groups

Studietyp

Interventionell

Inskrivning (Faktisk)

37

Fas

  • Fas 4

Kontakter och platser

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Studieorter

Deltagandekriterier

Forskare letar efter personer som passar en viss beskrivning, så kallade behörighetskriterier. Några exempel på dessa kriterier är en persons allmänna hälsotillstånd eller tidigare behandlingar.

Urvalskriterier

Åldrar som är berättigade till studier

20 år till 65 år (Vuxen, Äldre vuxen)

Tar emot friska volontärer

Nej

Kön som är behöriga för studier

Allt

Beskrivning

Inclusion Criteria:

  • ASA physical status I-II patients who were 20-65 years old and scheduled for general anaesthesia for urologic surgery

Exclusion Criteria:

  • Patients with an allergy to alpha-2 adrenergic agonists or propofol
  • Patients who anticipated difficult airway (cervical spinal disease, Mallampati score of III or IV, a mouth opening of <2.5 cm, and/or body mass index of >30 kg m-2), unstable teeth
  • Patients with bradycardia of <50 beats/min, heart block greater than first degree, severe cardiorespiratory dysfunction
  • Patients with symptoms of upper respiratory infection

Studieplan

Det här avsnittet ger detaljer om studieplanen, inklusive hur studien är utformad och vad studien mäter.

Hur är studien utformad?

Designdetaljer

  • Primärt syfte: Stödjande vård
  • Tilldelning: Randomiserad
  • Interventionsmodell: Enskild gruppuppgift
  • Maskning: Trippel

Vapen och interventioner

Deltagargrupp / Arm
Intervention / Behandling
Experimentell: Group D : Dexmedetomidine + propofol group
In Group D, DEX (1 µg kg-1) was intravenously loaded for 10 min before induction of anaesthesia.

All patients were pre-oxygenated with 100% oxygen with spontaneous breathing for 3 min before the end of loading of dexmedetomidine. Anaesthesia was induced with predetermined effect-site propofol concentrations using a target-controlled infusion device (Orchestra; Fresenius-Vial, Brezins, France). The first patient in Group D received an effect-site propofol concentration of 3 and 5 µg mL-1, respectively, over 5 min.

After equilibration of the plasma and effect-site propofol concentrations, i-gel (size 4 for patients weighing 50-90 kg, size 3 for patients weighing 30-50 kg) was inserted using the standard technique by a single anaesthesiologist staff member with expertise in i-gel insertion and who entered the operating room immediately before i-gel insertion to blind him to the group assignment.

Placebo-jämförare: Group C : Saline + propofol group
In Group C, 0.9% of normal saline (1 µg kg-1) was loaded 10 min before induction of anaeshtesia.

All patients were pre-oxygenated with 100% oxygen with spontaneous breathing for 3 min before the end of loading of normal saline. Anaesthesia was induced with predetermined effect-site propofol concentrations using a target-controlled infusion device (Orchestra; Fresenius-Vial, Brezins, France). The first patient in Group C received an effect-site propofol concentration of 3 and 5 µg mL-1, respectively, over 5 min.

After equilibration of the plasma and effect-site propofol concentrations, i-gel (size 4 for patients weighing 50-90 kg, size 3 for patients weighing 30-50 kg) was inserted using the standard technique by a single anaesthesiologist staff member with expertise in i-gel insertion and who entered the operating room immediately before i-gel insertion to blind him to the group assignment

Vad mäter studien?

Primära resultatmått

Resultatmått
Åtgärdsbeskrivning
Tidsram
EC50 of propofol required for successful i-gel insertion
Tidsram: During i-gel insertion anticipated up to 1 min
The EC50 of propofol for successful i-gel insertion was determined by a modification of Dixon's up-and-down method. The response of each patient determined the effect-site propofol concentration for the next patient. If the response was deemed 'successful', the next target concentration of propofol was decreased by 0.5 µg mL-1. If the response was deemed a 'failure', the target concentration was increased by the same dose. The process was repeated until the sixth crossover point (success/failure) was obtained.
During i-gel insertion anticipated up to 1 min

Sekundära resultatmått

Resultatmått
Åtgärdsbeskrivning
Tidsram
the total dose of propofol infused before i-gel insertion
Tidsram: During i-gel insertion time anticipated upto 1min
The total amount of propofol infused before i-gel insertion was noted. The insertion time, defined as the time from picking up the i-gel until the initiation of mechanical ventilation.
During i-gel insertion time anticipated upto 1min
the presence/severity of airway trauma after i-gel insertion
Tidsram: At the time point of removing the i-gel from patient's mouth
After removing the i-gel, airway trauma (defined as any blood staining on the device) was recorded.
At the time point of removing the i-gel from patient's mouth

Samarbetspartners och utredare

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Utredare

  • Studierektor: Hee Pyung Park, MD PhD, Professor
  • Huvudutredare: Young Cheol Kim, Md PhD, Professor

Publikationer och användbara länkar

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Studieavstämningsdatum

Dessa datum spårar framstegen för inlämningar av studieposter och sammanfattande resultat till ClinicalTrials.gov. Studieposter och rapporterade resultat granskas av National Library of Medicine (NLM) för att säkerställa att de uppfyller specifika kvalitetskontrollstandarder innan de publiceras på den offentliga webbplatsen.

Studera stora datum

Studiestart

1 maj 2012

Primärt slutförande (Faktisk)

1 augusti 2012

Avslutad studie (Faktisk)

1 augusti 2012

Studieregistreringsdatum

Först inskickad

24 mars 2014

Först inskickad som uppfyllde QC-kriterierna

24 mars 2014

Första postat (Uppskatta)

27 mars 2014

Uppdateringar av studier

Senaste uppdatering publicerad (Uppskatta)

27 mars 2014

Senaste inskickade uppdateringen som uppfyllde QC-kriterierna

24 mars 2014

Senast verifierad

1 mars 2014

Mer information

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