title: The effect of epidural injection speed on epidural pressure and distribution of solution in anesthetized dogs.
abstract: OBJECTIVE
  To determine the effect of injection speed on epidural pressure (EP), injection pressure (IP), epidural distribution (ED) of solution, and extent of sensory blockade (SB) during lumbosacral epidural anesthesia in dogs.
  
  
  METHODS
  Prospective experimental trial.
  
  
  METHODS
  Ten healthy adult Beagle dogs weighing 8.7 ± 1.6 kg.
  
  
  METHODS
  General anesthesia was induced with propofol administered intravenously and maintained with isoflurane. Keeping the dogs in sternal recumbency, two spinal needles connected to electrical pressure transducers were inserted into the L6-L7 and the L7-S1 intervertebral epidural spaces for EP and IP measurements, respectively. Bupivacaine 0.5% diluted in iohexol was administered epidurally to each dog via spinal needle at L7-S1 intervertebral space, at two rates of injection (1 and 2 mL minute(-1) groups), with a 1-week washout period. Epidural distribution was verified with computed tomography, and SB was evaluated after arousal by pinching the skin with a mosquito hemostatic forceps over the vertebral dermatomes. The results were analyzed according to each injection speed, using paired t- and Wilcoxon signed-rank tests.
  
  
  RESULTS
  Mean ± SD of baseline EP and IP values were 2.1 ± 6.1 and 2.6 ± 7.1 mmHg, respectively. Significant differences were observed between 1 and 2 mL minute(-1) groups for peak EP (23.1 ± 8.5 and 35.0 ± 14.5 mmHg, p = 0.047) and peak IP (68.5 ± 10.7 and 144.7 ± 32.6 mmHg, p <0.001). However, the median (range) of the ED, 11.5 (4-22) and 12 (5-21) vertebrae, and SB, 3.5 (0-20) and 1 (0-20) dermatomes, values of the two groups were not related to injection speed.
  
  
  CONCLUSIONS
  The EP profile during injection was measured by separating the injection and pressure monitoring lines. The increase in epidural injection speed increased the EP, but not the ED or the SB in dogs.
authors.affiliation: Department of Veterinary Clinical Sciences, College of Veterinary Medicine, Seoul National University, Seoul, South Korea.
authors.forename: Won-Gyun
authors.initials: WG
authors.lastname: Son
authors.forename: Min
authors.initials: M
authors.lastname: Jang
authors.forename: Junghee
authors.initials: J
authors.lastname: Yoon
authors.forename: Lyon Y
authors.initials: LY
authors.lastname: Lee
authors.forename: Inhyung
authors.initials: I
authors.lastname: Lee
mesh_terms: D000767:Anesthesia, Epidural / Q000662:veterinary*; D000779:Anesthetics, Local / Q000008:administration & dosage; D000818:Animals; D002045:Bupivacaine / Q000008:administration & dosage; D004285:Dogs / Q000502:physiology / Q000601:surgery*; D004334:Drug Administration Schedule / Q000662:veterinary; D004824:Epidural Space; D005260:Female; D007268:Injections, Epidural / Q000662:veterinary*; D008159:Lumbar Vertebrae; D008297:Male; D011312:Pressure; D011446:Prospective Studies; D014057:Tomography, X-Ray Computed / Q000662:veterinary
chemical_list: D000779:Anesthetics, Local; D002045:Bupivacaine
keywords: dog; epidural; injection; pressure; speed