title: Effect of intravenous ondansetron on reducing the incidence of hypotension and bradycardia events during shoulder arthroscopy in sitting position under interscalene brachial plexus block: A prospective randomized trial.
abstract: OBJECTIVE
  Sudden, profound hypotension and bradycardia events (HBEs) have been reported in more than 20% of patients undergoing shoulder arthroscopy in the sitting position. The present study was designed to know whether intravenous (IV) ondansetron (selective 5-hydroxy tryptamine 3-antagonist) can help in reducing the HBEs associated with shoulder arthroscopy performed in sitting position under interscalene brachial plexus block (ISBPB).
  
  
  METHODS
  A total of 100 patients (age 20-50 years) undergoing shoulder arthroscopy performed in the sitting position under ISBPB were assigned randomly to one of the two groups: Group C received 10 ml of normal saline and Group T received 4 mg of ondansetron diluted in 10 ml of normal saline` IV. All patients received ISBPB using levobupivacaine 0.5%. Assessment of motor and sensory blockade, pulse rate, systolic blood pressure, respiration, and side effects were noted every 5 min for first 30 min and every 10 min till the end of surgery. HBEs were recorded in both groups.
  
  
  RESULTS
  IV injection of ondansetron significantly reduces the incidence of HBEs from 11 (22.44% in Group C) to 3 (6.1% in Group T). The duration of analgesia was significantly longer in Group C (8.1 ± 3.3) in comparison with Group T (6.3 ± 4.2 h).
  
  
  CONCLUSIONS
  We conclude that 4 ml of IV ondansetron can significantly reduce the HBEs during shoulder arthroscopy done in the sitting position under ISBPB.
authors.affiliation: Department of Anaesthesiology, Melmaruvathur Adhiparasakthi Institute of Medical Sciences, Melmaruvathur, Kancheepuram, Tamil Nadu, India.
authors.forename: Srinivasa Rao
authors.initials: SR
authors.lastname: Nallam
authors.affiliation: Department of Anaesthesiology, Melmaruvathur Adhiparasakthi Institute of Medical Sciences, Melmaruvathur, Kancheepuram, Tamil Nadu, India.
authors.forename: Sudheer
authors.initials: S
authors.lastname: Dara
keywords: Arthroscopy; bradycardia; hypotension; interscalene brachial block; intravenous ondansetron; sitting position