Table 1

Characteristics of included studies

ReferenceCountryStudy designStudy settingParticipantsInterventionControlFollow-up durationPrimary outcome measureSecondary outcome measures
Vahidi et al 32 IranDouble-blind parallel RCTEmergency department of tertiary referral centren=40 (20 intervention, 20 control)Lidocaine: lidocaine solution (2 mg/kg) intravenous over 5 minMorphine solution (0.1 mg/kg) intravenous over 5 minAssessed before, 15 and 30 min after initiation of infusionVAS (0–10)None
Morris-Stiff et al 35 Wales, UKProspective observational study (pilot study)Outpatients under vascular surgery teamn=20 (consecutive patients)
17 completed study
Gabapentin: 300 mg daily, titrated to 300 mg three times a day within 3 days Increased to 600 mg three times a day as indicatedNoneAssessed at baseline, 4, 7, 14, 28 days or until surgical intervention or deathVAS (0–10)Night pain score, opioid requirements
Aurilio et al 36 ItalyOpen-label randomised trialSurgical outpatients in a tertiary referral centren=86 (44 intervention, 42 control)Buprenorphine (35 µg/hour) patch+epidural infusion of ropivacaine/morphine (200 mg+2 mg)Placebo patch+epidural infusion of ropivacaine/morphine (200 mg+2 mg)4 weeks with twice weekly contact by researcherVAS (0–100)Short-Form McGill Pain Questionnaire, sleep quality, morphine requirements, patient satisfaction, psychobehavioural evaluation (Hamilton Scale)
Aurilio et al 28 ItalyOpen-label randomised trialPatients under vascular surgery awaiting surgeryn=43 (22 intervention, 21 control)Buprenorphine (35 µg/hour) patch+epidural 100 mL of ropivacaine (2 mg/mL) and 2 mg of morphine at 4 mL/hourEpidural 100 mL of ropivacaine (2 mg/mL) and 2 mg of morphine at 4 mL/hour rate30-day observation periodVAS (0–100)Hours of sleep, adjustment of spinal dose of morphine
Mitchell and Fallon33 Scotland, UKDouble-blind placebo controlled RCTPatients under the care of vascular surgeryn=35 (20 male, 15 female)
7 withdrew so final analysis:
16 intervention, 12 placebo
Ketamine: intravenous ketamine 0.6 mg/kg in 0.9% saline over 4 hoursIntravenous placebo (0.9% saline) over 4 hoursAssessed at entry to study, prior to infusion, 24 hours after infusion and on average 5 days postinfusionBrief Pain InventoryOpioid requirements, presence of allodynia/hyperpathia/hyperalgesia
Persson et al
SwedenCrossover, double-blind RCTAll referred from vascular surgeryn=8Ketamine: racemic ketamine hydrochloride 0.15, 0.3, 0.45 mg/kg intravenous over 5 minMorphine-hydrochloride 10 mg intravenous over 5 minVAS scores at 2.5, 5, 10, 20, 30, 40, 50 and 60 minVAS (0–10)None
  • RCT, randomised controlled trial; VAS, visual analogue scale.