 this study was done on 40 American Society of AnaesthesiologistASA I II live donors of either sex in adult age group undergoing laparoscopic live donor nephrectomy. After getting approval from institutes ethical committee and written informed consent, Donors were randomly allocated to either of two group. Anaesthesia was induced with injection morphine 0.1 mgkg, injection propofol 1-2 mgkg and vecuronium 0.1 mgkg. Maintenance of anaesthesia was done with isoflurane and oxygen. After induction donors were placed into modified flank position with left side upward. Donors in Group A received Acetazolamide 5 mgkg via orogastric tube soon after the induction of anaesthesia. Group S received saline as a placebo. investigator and subjects were blinded till the statistical analysis. Optic nerve sheath diameter was measured six times during perioperative periods by using high frequency ultrasound probe. Intra operative monitoring was done for Heart rate, Blood Pressure, pulse oximetrySpo2, End Tidal Carbon DioxideETCO2, Train Of FourTOF and Bi spectral indexBIS. Post operatively donors were reversed with injection neostigmine and glycopyrrolate. 