title: A randomized controlled study comparing intrathecal hyperbaric bupivacaine-fentanyl mixture and isobaric bupivacaine-fentanyl mixture in common urological procedures.
abstract: OBJECTIVE
  Bupivacaine is available in isobaric and hyperbaric forms for intrathecal use and opioids are used as additives to modify their effects. The aim of this study was to compare the efficacy and haemodynamic effect of intrathecal isobaric bupivacaine-fentanyl mixture and hyperbaric bupivacaine-fentanyl mixture in common urological procedures.
  
  
  METHODS
  One hundred American Society of Anesthesiologists physical status 1 and 2 patients undergoing urological procedures were randomized into two groups. Group 1 received 3 ml of 0.5% isobaric bupivacaine with 25 μg fentanyl while Group 2 received 3 ml of 0.5% hyperbaric bupivacaine with 25 μg fentanyl. The parameters measured include heart rate, blood pressure, respiratory rate, onset and duration of motor and sensory blockade. Student's unpaired t-test and the χ(2) test were used to analyse the results, using the SPSS version 11.5 software.
  
  
  RESULTS
  The haemodynamic stability was better with isobaric bupivacaine fentanyl mixture (Group 1) than with hyperbaric bupivacaine fentanyl mixture (Group 2). The mean onset time in Group 1 for both sensory block (4 min) and motor block (5 min) was longer compared with Group 2. The duration of sensory block (127.8 ± 38.64 min) and motor block (170.4 ± 27.8 min) was less with isobaric bupivacaine group compared with hyperbaric bupivacaine group (sensory blockade 185.4 ± 16.08 min and motor blockade 201.6 ± 14.28 min). Seventy percent of patients in Group 2 had maximum sensory block level of T6 whereas it was 53% in Group 1. More patients in Group 1 required sedation compared to Group 2.
  
  
  CONCLUSIONS
  Isobaric bupivacaine fentanyl mixture was found to provide adequate anaesthesia with minimal incidence of haemodynamic instability.
authors.affiliation: Department of Anaesthesia, Kasturba Medical College, Manipal University, Mangalore, Karnataka, India.
authors.forename: Madhusudan
authors.initials: M
authors.lastname: Upadya
authors.affiliation: Department of Anaesthesia, Kasturba Medical College, Manipal University, Mangalore, Karnataka, India.
authors.forename: S
authors.initials: S
authors.lastname: Neeta
authors.affiliation: Department of Anaesthesia, Kasturba Medical College, Manipal University, Mangalore, Karnataka, India.
authors.forename: Jesni Joseph
authors.initials: JJ
authors.lastname: Manissery
authors.affiliation: Department of Anaesthesia, Sultan Qaboos University Hospital, Muscat, Sultanate of Oman.
authors.forename: Nigel
authors.initials: N
authors.lastname: Kuriakose
authors.affiliation: Department of Anaesthesia, Rajendra Institute of Medical Sciences, Ranchi, Jharkand, India.
authors.forename: Rakesh Raushan
authors.initials: RR
authors.lastname: Singh
keywords: Bupivacaine; fentanyl; hyperbaric; isobaric; spinal anaesthesia