title: Intratesticular and subcutaneous lidocaine alters the intraoperative haemodynamic responses and heart rate variability in male cats undergoing castration.
abstract: OBJECTIVE
  To evaluate the usefulness of intratesticular and subcutaneous lidocaine in alleviating the intraoperative nociceptive response to castration, measured by pulse rate (PR) and mean arterial pressure (MAP), and to test the applicability of heart rate variability (HRV) analysis in assessing this response.
  
  
  METHODS
  Randomized, controlled, observer-blinded experimental trial.
  
  
  METHODS
  Thirty-nine healthy male cats admitted for castration.
  
  
  METHODS
  One group received general anaesthesia and served as control group (GA), while the treatment group (LA) additionally received local anaesthesia (lidocaine 2 mg kg(-1)) intratesticularly and subcutaneously. PR and MAP were recorded at anaesthesia baseline (T0), treatment (T1), incision left testicle (T2), traction on spermatic cord (T3), tightening of the autoligature and resection of the cord (T4), incision on the right side (T5), traction on spermatic cord (T6), and tightening of the autoligature and resection of cord (T7). HRV analysis was divided into three 5-minute intervals: baseline (H0), treatment (H1), and surgery (H2).
  
  
  RESULTS
  There were significant increases in PR and MAP for both groups during surgery from T3 onwards; however, the increase in the treatment group (LA) was significantly lower than for the control group (GA). For HRV analysis, significant differences were found between groups in the following parameters during surgery: TP (total power), VLF (very low frequency), SDNN (standard deviation of NN intervals [= the interval between two consecutive R-waves in the ECG]), and TI (triangular index), which were lower in the LA group. Mean NN was significantly lower in the GA group, whereas LF (low frequency) and LFn (low frequency, normalized value) were lower in the LA group. HF (high frequency) and HFn (high frequency, normalized value) decreased significantly from H1 to H2 in both groups.
  
  
  CONCLUSIONS
  The study showed that the nociceptive response to surgery was alleviated by the use of intratesticular and subcutaneous lidocaine and that HRV analysis is a promising research tool to estimate intraoperative nociception in cats during general anaesthesia.
authors.affiliation: Department of Small Animal Clinical Sciences, Faculty of Life Sciences, University of Copenhagen, Frederiksberg C, Denmark. elena.moldal@nvh.no
authors.forename: Elena R
authors.initials: ER
authors.lastname: Moldal
authors.forename: Thomas
authors.initials: T
authors.lastname: Eriksen
authors.forename: Jolle
authors.initials: J
authors.lastname: Kirpensteijn
authors.forename: Ane
authors.initials: A
authors.lastname: Nødtvedt
authors.forename: Annemarie T
authors.initials: AT
authors.lastname: Kristensen
authors.forename: Fiorella M
authors.initials: FM
authors.lastname: Sparta
authors.forename: H Andreas
authors.initials: HA
authors.lastname: Haga
mesh_terms: D000768:Anesthesia, General / Q000662:veterinary; D000779:Anesthetics, Local; D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D002415:Cats; D006339:Heart Rate / Q000187:drug effects*; D006439:Hemodynamics / Q000187:drug effects*; D007267:Injections / Q000662:veterinary; D007279:Injections, Subcutaneous / Q000662:veterinary; D007432:Intraoperative Period; D008012:Lidocaine / Q000008:administration & dosage; D008297:Male; D009919:Orchiectomy / Q000379:methods / Q000662:veterinary*; D013737:Testis / Q000187:drug effects
chemical_list: D000779:Anesthetics, Local; D008012:Lidocaine