Evaluation of Anxiolysis and Pain Associated With Retrobulbar Eye Block for Cataract Surgery : Melatonin Versus Gabapentin
Condition: Anxiety; Pain
MeSH terms: Cataract
Study type: Interventional
Phase: Phase 1/Phase 2

Summary: 
      Principle goals of sedation for eye surgery are to provide patient comfort and to allow the
      patient to stay calm during both retrobulbar injection and surgery. Insufficient sedation may
      not prevent the patient from moving during retrobulbar injection, whereas very deep sedation
      may result in respiratory complications during surgery .The investigators compared the effect
      of melatonin and gabapentin on the hemodynamic parameters, sedation ,anxiety, and pain and
      satisfaction profile in cataract surgery. After approval by the Hospital Evaluation Committee
      of Scientific Studies for ethical purpose and written informed consent, ninety patients
      scheduled for cataract surgery by phacoemulsification were randomly allocated to three study
      groups to receive melatonin 6 mg (Group M, n = 30) , gabapentin 600mg(GroupG, n = 30)or
      placebo(GroupP, n=30) 90 minutes before retrobulbar injection. . Hemodynamic parameters
      ,anxiety, sedation score , and pain during block and surgery, satisfaction of surgeon were
      assessed. . At the preoperative visit verbal pain score (VPS) of 10 (0 = no pain and 10 =
      worst pain imaginable) and verbal anxiety score (VAS) ranging from 0 to 10 (0= completely
      calm, 10 = the worst possible anxiety) were explained to patients. Then a 20 gauge cannula
      was inserted into one of the two hands. Patients were monitored with electrocardiogram,
      noninvasive measurement of blood pressure, and pulse oximetry (SPO2). Retrobulbar nerve block
      was performed by the same ophthalmic surgeon who was unaware of group allocation with 1.5 ml
      of solution that prepared by nurse( lidocaine 2%and 0.5 ml bupivacaine) via the percutaneous
      route with a 25 G, 38 mm Atkinson needle (John Weiss & Son Limited, Milton Keynes,England),
      at inferotemporal site. No patient received an additional facial nerve block. The
      investigators assessed the pain immediately after block and surgery. Anxiety score and pain
      score was recorded in each patient before premedication (T1), ninety minutes after
      premedication, on arrival in the operating room (T2), one minute after retrobulbar block
      placement (T3)during the operation period) (T4) and postoperatively before discharging the
      patient from the recovery room (T5) .At the end of surgery, the patients were asked about
      average level of their anxiety and pain during the operation period according to the VAS and
      VPS explained to them before premedication.'. The surgeon was also asked to verbally rate
      their level of satisfaction according to three degree scale as "very bad, , moderate, good
      after the operation. The sedation level of patients during performance of block was assessed
      as Sedation scores were obtained on a 3 point scale with 0 =movements of the head, arms and
      trunk ,1 =slightly movement of arms,2=slightly change in face,3=complete calm. If sedation
      was inadequate, fentanyl could be given 0.5microgram/kg as needed.
    


Intervention name(s): Melatonin; Gabapentin; placebo
Intervention type(s): Drug; Drug; Drug
Intervention description(s): ninety patients scheduled for cataract surgery by phacoemulsification were randomly allocated to three study groups to receive melatonin 6
mg (Group M, n = 30) , gabapentin 600mg(GroupG, n = 30)or placebo(GroupP, n=30) orally 90 minutes before retrobulbar injection( for all of three groups).; ninety patients scheduled for cataract surgery by phacoemulsification were randomly allocated to three study groups to receive melatonin 6
mg (Group M, n = 30) , gabapentin 600mg(GroupG, n = 30)or placebo(GroupP, n=30) orally 90 minutes before retrobulbar injection( for all of three groups).; ninety patients scheduled for cataract surgery by phacoemulsification were randomly allocated to three study groups to receive melatonin 6
mg (Group M, n = 30) , gabapentin 600mg(GroupG, n = 30)or placebo(GroupP, n=30) orally 90 minutes before retrobulbar injection( for all of three groups).
Intervention MeSH terms: Gabapentin; Melatonin
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Quadruple (Participant, Care Provider, Investigator, Outcomes Assessor)
Primary purpose: Prevention
Keywords: melatonin; gabapentin; anxiety; pain; retrobulbar block