Evaluation of Anxiolysis and Pain Associated With Retrobulbar Eye Block for Cataract Surgery : Melatonin Versus Gabapentin

Evaluation of Anxiolysis and Pain Associated With Retrobulbar Eye Block for Cataract Surgery : Melatonin Versus Gabapentin ( A Randomized, Double-blind, Placebo-controlled Study)

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.

Study Overview

• Status: Completed
• Conditions: Pain; Anxiety
• Intervention / Treatment: Drug: Melatonin; Drug: Gabapentin; Drug: placebo

• Study Type: Interventional
• Enrollment (Actual): 90
• Phase: Phase 2; Phase 1

Contacts and Locations

Study Locations

• Iran, Islamic Republic of
  • Qazvin, Iran, Islamic Republic of, 34197/59811
    • Qazvin university of medical science

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 31 years to 81 years (Adult, Older Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

Description

Inclusion Criteria:

• patients who were aged 25 years or older, American Society of Anesthesiologists (ASA) physical status I-III

Exclusion Criteria:

• Patients with ASA status IV
• history of hepatic or renal disease, confusion, dementia
• communication difficulty resulting from deafness or language barrier
• chronic use of narcotics, barbiturates or psychotropic medications
• history of allergy or contraindications to any of the study drugs
• visual impairment of the non operative eye
• weight < 40 kg or > 100 kg

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Prevention
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Quadruple

Number of Arms

3

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Active Comparator: melatonin; 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).	Drug: Melatonin; 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).
Active Comparator: gabapentin; 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).	Drug: Gabapentin; 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).
Placebo Comparator: placebo; 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).	Drug: placebo; 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).

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Time Frame
pain will be assessed by verbal pain score (VPS) of 10 (0 = no pain and 10 = worst pain imaginable)	one minute after retrobulbar block placement
pain will be assessed by verbal pain score (VPS) of 10 (0 = no pain and 10 = worst pain imaginable)	At the end of surgery the patients were asked about average level of their pain during the operation period according to the VPS explained to them before premedication)
pain will be assessed by verbal pain score (VPS) of 10 (0 = no pain and 10 = worst pain imaginable)	postoperatively before discharging the patient from the recovery room
anxiety will be assessed by verbal anxiety score (VAS) of 10 (0 = completely calm and 10 = the worst possible anxiety)	At the end of surgery the patients were asked about average level of their pain during the operation period according to the VPS explained to them before premedication)
anxiety will be assessed by verbal anxiety score (VAS) of 10 (0 = completely calm and 10 = the worst possible anxiety)	one minute after retrobulbar block placement
anxiety will be assessed by verbal anxiety score (VAS) of 10 (0 = completely calm and 10 = the worst possible anxiety)	postoperatively before discharging the patient from the recovery room

Secondary Outcome Measures

Outcome Measure	Time Frame
mean arterial blood pressure will be assessed by noninvasive automatic blood pressure measurement	before premedication
mean arterial blood pressure will be assessed by noninvasive automatic blood pressure measurement	ninety minutes after premedication, on arrival in the operating room
mean arterial blood pressure will be assessed by noninvasive automatic blood pressure measurement	one minute after retrobulbar block placement
mean arterial blood pressure will be assessed by noninvasive automatic blood pressure measurement	during the operation period(five minutes after beginning of surgery
mean arterial blood pressure will be assessed by noninvasive automatic blood pressure measurement	postoperatively before discharge the patient from the recovery room
heart rate will be assessed by echocardiogram monitoring	before premedication
heart rate will be assessed by echocardiogram monitoring	ninety minutes after premedication, on arrival in the operating room
heart rate will be assessed by echocardiogram monitoring	one minute after retrobulbar block placement
heart rate will be assessed by echocardiogram monitoring	during the operation period(five minutes after beginning of surgery
heart rate will be assessed by echocardiogram monitoring	postoperatively before discharge the patient from the recovery room
satisfaction of surgeon according to three degree scale as very bad, moderate, good will be assessed	one minute after retrobulbar block placement
satisfaction of surgeon according to three degree scale as very bad, moderate, good will be assessed	at the end of surgery

Collaborators and Investigators

• Sponsor: Qazvin University Of Medical Sciences

Study record dates

Study Major Dates

• Study Start: September 1, 2010
• Primary Completion (Actual): December 1, 2010
• Study Completion (Actual): January 1, 2011

Study Registration Dates

• First Submitted: September 10, 2010
• First Submitted That Met QC Criteria: September 10, 2010
• First Posted (Estimate): September 13, 2010

Study Record Updates

• Last Update Posted (Estimate): October 11, 2012
• Last Update Submitted That Met QC Criteria: October 10, 2012
• Last Verified: October 1, 2012

More Information

Terms related to this study

• Keywords: pain; melatonin; anxiety; gabapentin; retrobulbar block
• Additional Relevant MeSH Terms: Eye Diseases; Lens Diseases; Cataract; Physiological Effects of Drugs; Neurotransmitter Agents; Molecular Mechanisms of Pharmacological Action; Central Nervous System Depressants; Peripheral Nervous System Agents; Analgesics; Sensory System Agents; Excitatory Amino Acid Antagonists; Excitatory Amino Acid Agents; Protective Agents; Tranquilizing Agents; Psychotropic Drugs; Anti-Anxiety Agents; Anticonvulsants; Antimanic Agents; Antioxidants; Gabapentin; Melatonin
• Other Study ID Numbers: ACTRN12610000727044