title: Subarachnoid pressures and cardiorespiratory parameters during cisternal myelography in isoflurane anaesthetized dogs.
abstract: OBJECTIVE
  To measure subarachnoid pressures, systemic circulatory and respiratory effects, and to calculate cerebral perfusion pressure during cisternal myelography.
  
  
  METHODS
  Prospective clinical study.
  
  
  METHODS
  Forty-three client owned dogs with clinical signs of spinal disease, weighing 6-56 kg.
  
  
  METHODS
  Dogs were premedicated with butorphanol and diazepam intravenously (IV) and anaesthesia was induced with propofol and maintained with isoflurane vaporized in oxygen. Ventilation was spontaneous. Heart and respiratory rates, invasive mean arterial blood pressure (MAP), end tidal carbon dioxide and isoflurane concentration were measured continuously. Initial subarachnoid pressure (SaP0 ) was measured in the cisterna magna with a needle pressure gauge. Iohexol 0.3 mL kg(-1) was injected at a rate of 4.1 mL minute(-1) into the cerebellomedullary cistern. The SaP was recorded during and at 120 seconds after contrast administration. The maximum SaP (SaPmax ) and minimum calculated cerebral perfusion pressure (CPPmin ) were recorded for each case.
  
  
  RESULTS
  Prior to contrast injection, mean ± SD, MAP was 73 ± 20 mmHg and SaP0 was 10 ± 3 mmHg. The cerebral perfusion pressure (CPP) was 64 ± 20 mmHg. The contrast injection increased the SaP0 to 73 ± 33 mmHg (SaPmax ). After injection, MAP increased to 97 ± 25 mmHg and the CPP decreased to 14 ± 34 mmHg. A negative correlation was found between the lowest CPP and body weight (ρ = -0.77, p < 0.0001). Nine dogs had bradycardia, apnoea and hypertension, 21 dogs had at least one of these signs. The number of clinical signs showed significant correlation with body weight (ρ = -0.68, p < 0.0001), SaPmax (ρ = -0.66, p < 0.0001) and CPPmin (ρ = -0.73, p < 0.0001).
  
  
  CONCLUSIONS
  Cerebral perfusion can severely decrease during cisternal myelography using the standard dose of iohexol. Bradycardia, apnoea and systemic hypertension were associated with decreased CPP.
authors: Department of Surgery and Ophthalmology, Faculty of Veterinary Science, Szent Istvan University, Budapest, Hungary. arany.toth.attila@aotk.szie.hu
authors: Attila
authors: A
authors: Arany-Tóth
authors: Péter
authors: P
authors: Csébi
authors: Jenő
authors: J
authors: Reiczigel
authors: Viktoria
authors: V
authors: Sére
authors: Tibor
authors: T
authors: Németh
mesh_terms: D000818:Animals; D002245:Carbon Dioxide; D004285:Dogs; D005260:Female; D006339:Heart Rate / Q000187:drug effects*; D007427:Intracranial Pressure / Q000187:drug effects*; D007530:Isoflurane / Q000008:administration & dosage / Q000494:pharmacology*; D008297:Male; D009192:Myelography / Q000662:veterinary*; D012119:Respiration / Q000187:drug effects*
chemical_list: D002245:Carbon Dioxide; D007530:Isoflurane