Conscious sedation for cataract surgery done under retrobulbar block – a comparative study evaluating the effects of midazolam and dexmedetomidine

Abstract

NEED FOR THE STUDY: 1. Cataract surgeries were carried out under local anesthesia, 2. A comfortable co-operative stationary patient is a key to achieve good result with these patients, 3. Hence in this study conscious sedation supplemented with Peribulbar block has been carried out and results were observed for; • better patient cooperation, • anxiolysis and patient comfortness, • surgeons satisfaction, • Stable hemodynamics, • Lack of complication, AIM AND OBJECTIVES: 1. To study the effects of conscious sedation in cataract surgery. 2. In this study we compare the effect of midazolam with dexmedetomidine and with that of control group. Method of Collection of Data: Prospective randomised double blind clinical control trial METHODOLOGY: 1. After obtaining informed written consent, patients will be randomly divided into 3 groups by draw of lots. 2. Group M-patients receiving midazolam, Loading dose-0.03mg/kg, Maintenance dose-0.05mg/kg/hr. 3. Group D-patients receiving dexmedetomidine, Loading dose-0.3mcg/kg over ten min, Maintenance dose-0.3mcg/kg/hr. 4. Group C-control. Loading dose – plain 0.9% N.S, Maintenance dose- plain 0.9% N.S. 5. Loading dose is followed by peri bulbar block after 10 min. 6. Maintenance dose is given in infusion throughout the procedure and infusion is stopped at the end of surgery. 7. Supplemental oxygen will not be provided except in case of desaturation (SPO2-95%). PARAMETERS MONITORED: Baseline B.P, Pulse rate, SPO2. Blood pressure, pulse rate, SPO2, R.S, S every 2 min from the time of loading dose to the time the surgery was started. Wong Baker Facial pain rating scale at the time of retrobulbar block. Intra op vitals-B.P, pulse rate, E.C.G, SPO2 every 5 min Ramsay sedation score every 1 min from the time of loading dose till they attain the Ramsay sedation score of 3 and every 5 min there after Patient movement scale during surgery. Aldrete recovery score every min after the end of surgery and time to attain the score of 10 was recorded. Patient was shifted to recovery room after they attain a Aldrete recovery score of 10. Likert like verbal rating of surgeon’s satisfaction at the end of surgery. Patient will be asked whether they were aware of ‘unpleasant intraoperative events’ in the post operative period. Post op vitals and Ramsay sedation score every 10 min for 2hrs in the post op period. RESULTS: We found that conscious sedation was safe and effective in the case of cataract surgery and was associated with greater patient’s comfort and surgeon’s satisfaction when compared to the surgeries which was done only with retro bulbar block alone. Midazolam in a loading dose of 0.05mg/kg and in a maintenance dose of 0.03mg/kg was equally effective to dexmedetomidine in the aspect of patient’s co- operation during retro bulbar block and during surgery which was assessed by facial pain scale, patient movement scale and surgeon satisfaction scale and recall of intra op events. Midazolam was slightly better to dexmedetomidine in the aspect of better hemodynamic profile. However mean time to reach RSS of 3 was rapid with dexmedetomidine when compared to midazolam. But time to reach Aldrete recovery score 10 was prolonged in dexmedetomidine when compared to midazolam. Both the drugs had no significant complications in the peri operative period. CONCLUSION: We conclude that conscious sedation is safe and effective to practise in the case of cataract surgeries and is associated with better patient co operation and surgeon comfort when compared to the surgeries which are done with retrobulbar block alone. Midazolam and dexmedetomidine are equally effective in the aspects of patient co operation and surgeon’s comfort but midazolam is slightly superior to dexmedetomidine in the aspect of better hemodynamic profile.