Spinal or Intravenous Dexmedetomidine in Ambulatory Surgery
Condition: Surgery Ambulatory
Study type: Interventional
Phase: Phase 4

Summary: 
      The primary objective of this double blind randomized study is to determine the effect of
      dexmedetomidine on onset and duration of the sensory and motor block and on the influence on
      bladder function after spinal anesthesia with chloroprocaine. Our primary hypothesis is that
      sensory block will significantly be prolonged by dexmedetomidine administered by both the
      spinal and the intravenous route. The investigators do not expect a significant difference in
      motor block duration between intravenous or spinal administration. Secondary outcomes are
      micturition problems, duration of analgesia and the occurrence of side effects such as
      sedation and hypotension.
    

Detailed description: 
      The study is designed as a multicenter study and randomization and inclusion of patients will
      be performed in three hospitals. Each hospital has its own randomisation sequence and
      coordinating investigator who will be responsible for appointing blinded and unblinded
      participators in the study.

      Patients scheduled for spinal anesthesia in ambulatory surgery will be randomized by sealed
      envelopes (computer generated sequence) into one of the following three study groups:

      spinal chloroprocaine 40 mg with spinal dexmedetomidine (5mcg) spinal chloroprocaine 40 mg
      with intravenous dexmedetomidine ( 0.5 mcg/kg) spinal chloroprocaine 40 mg alone (control
      group)

      All patients will receive the same amount of spinal solution, containing chloroprocaine 1% (4
      ml) with dexmedetomidine (0.5 ml, 1 mcg/ml) or NaCl ( sodiumchloride) 0,9% (0.5 ml ) ( and 50
      ml intravenous Nacl 0.9, containing dexmedetomidine (0.5 mcg/kg) or not depending on the
      study group. All solutions are prepared by an independent anesthesiologist and labelled as
      Intravenous study medication and spinal study medication. Spinal anesthesia and data
      registration will be done by a blinded anesthesist and/or study nurse on a data sheet
      designed for the study.

      Spinal anesthesia is performed in the lateral decubitus at L3-L4 vertebral interspace and
      standard monitoring for this procedure is applied. Insufficient analgesia will be treated
      with sufentanil increments. Hypotension and bradycardia will be treated with ephedrine and
      atropine. Patients will be discharged when the block is regressed, there is no sedation or
      nausea and nrs scores of pain are below 4. Patients will be contacted by telephone after one
      week to evaluate any postoperative complaints.Micturition will receive a score based on
      bladder volumes measured by bladder scanning and subjective complaints . This score system
      was used in two of our former studies (1,2)

      To calculate the power of this study, we used the mean L2 regression of a previous study
      after spinal chloroprocaine with its standard deviation (SD 20 min, mean 90 min) and compared
      it to a mean increase with 30 %. We calculated that we should include 7 patients in each
      group to obtain a power of 80%.

      To be sure to detect a possible difference in discharge time as well, we calculated a sample
      size of 48 patients for each group to detect a 30-minute difference.

      Statistical analysis will be done with ANOVA analysis , A kruskal-Wallis of Mann Whitney test
      depending on the distribution of the population and if the values are parametric or not. This
      will be done by spss.
    

Intervention name(s): spinal dexmedetomidine 0.5 mcg; spinal chloroprocaine 40 mg; IV dexmedetomidine 0.5 mcg/kg
Intervention type(s): Drug; Other; Drug
Intervention description(s): Administration of dexmedetomidine 0.5 mcg; spinal anesthesia with chloroprocaine 40 mg; intravenous administration of dexmedetomidine 0.5 mcg/kg
Other intervention name(s): dexdor; ampres; dexdor
Intervention MeSH terms: Dexmedetomidine; Chloroprocaine
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Triple (Participant, Care Provider, Outcomes Assessor)
Primary purpose: Other
Keywords: spinal or intravenous dexmedetomidine