title: Arrhythmias and transient changes in cardiac function after topical administration of one drop of phenylephrine 10% in an adult cat undergoing conjunctival graft.
abstract: METHODS
  A 2-year-old, entire female, Somali cat weighing 3.8 kg was admitted for a conjunctival graft on the right eye, for treatment of an acute descemetocele. Medetomidine 4.2 μg kg(-1) and methadone 0.2 mg kg(-1) were administered by intramuscular injection as preanaesthetic medication. Anaesthesia was induced using diazepam 0.26 mg kg(-1) and propofol 4 mg kg(-1) administered by intravenous (i.v.) injection. Following endotracheal intubation, anaesthesia was maintained with isoflurane delivered in oxygen (1 L minute(-1)) and nitrous oxide (2 L minute(-1)) via a non-rebreathing system. Twenty minutes after induction of anaesthesia, one drop of a 10% phenylephrine hydrochloride solution was administered topically to the right eye.
  
  
  METHODS
  After phenylephrine administration, a decrease in heart rate (from 95 to 80 beats minute(-1)) and an increase in arterial blood pressure occurred. The pulse then became difficult to palpate manually and multifocal ventricular premature contractions were observed on the electrocardiogram.
  
  
  RESULTS
  Nitrous oxide was discontinued and the isoflurane vaporizer setting was decreased from 1.5% to 0.5%. Lidocaine 1 mg kg(-1) i.v. was administered, this resulted in ventricular bigeminy. The quality of the femoral pulse improved and was regular in rhythm and character. Surgery was completed as fast as possible. The bigeminy progressively disappeared and before disconnecting the cat from the breathing system, there was a normal sinus rhythm with a heart rate of 85 beats minute(-1).
  
  
  RESULTS
  Echocardiography was performed during recovery and showed mitral and aortic valve insufficiency and dilation of the left ventricle, suggesting a reduction in systolic function. Echocardiography was repeated the following day and was normal.
  
  
  CONCLUSIONS
  In order to diminish the potential for cardiovascular sequelae associated with systemic absorption of ocular phenylephrine, less concentrated solutions, smaller drop size or different instillation techniques should be considered for topical use in small patients.
authors.affiliation: Department of Veterinary Clinical Science, University of Padua, Legnaro Padua, Italy. franci@unipd.it
authors.forename: Paolo
authors.initials: P
authors.lastname: Franci
authors.forename: Elizabeth A
authors.initials: EA
authors.lastname: Leece
authors.forename: J Fraser
authors.initials: JF
authors.lastname: McConnell
mesh_terms: D000287:Administration, Topical; D000818:Animals; D001145:Arrhythmias, Cardiac / Q000139:chemically induced / Q000662:veterinary*; D002371:Cat Diseases / Q000601:surgery*; D002415:Cats; D003228:Conjunctiva / Q000637:transplantation*; D003229:Conjunctival Diseases / Q000601:surgery / Q000662:veterinary*; D004562:Electrocardiography / Q000662:veterinary; D005260:Female; D006339:Heart Rate / Q000187:drug effects*; D010656:Phenylephrine / Q000008:administration & dosage / Q000009:adverse effects*; D011674:Pulse / Q000662:veterinary; D014662:Vasoconstrictor Agents / Q000008:administration & dosage / Q000009:adverse effects*
chemical_list: D014662:Vasoconstrictor Agents; D010656:Phenylephrine