title: The effects of surgery and anesthesia on blood magnesium and calcium concentrations in canine and feline patients.
abstract: OBJECTIVE
  To demonstrate the effect of anesthesia and surgery on serum ionized magnesium and ionized calcium concentrations in clinical canine and feline patients.
  
  
  METHODS
  37 client-owned dogs, ASA PS I-III and 10 client-owned cats, ASA PS I, all receiving anesthesia for elective or emergent surgery at a Veterinary Teaching Hospital.
  
  
  METHODS
  Plasma ionized and serum total magnesium, and plasma ionized calcium were measured prior to and after a group-standardized anesthetic protocol.
  
  
  RESULTS
  Regardless of pre-operative medication (hydromorphone or butorphanol), anesthetic induction (thiopental or lidocaine/hydromorphone/diazepam (LHD) and propofol combination), or type of surgical procedure (peripheral surgery or laparotomy), post-operative plasma ionized calcium concentration decreased in all groups of dogs, while post-operative plasma ionized magnesium increased in all groups, although the changes were not always significant. The dogs who were induced with an LHD and propofol technique had a greater increase in ionized magnesium (0.36 +/- 0.07 to 0.42 +/- 0.07 mmol L(-1)) than the group in which anesthesia was induced with thiopental (0.41 +/- 0.07 to 0.42 +/- 0.07 mmol L(-1), p = 0.009). The cats showed similar changes in ionized magnesium and ionized calcium, and also had a significant increase in serum total magnesium (2.17 +/- 0.20 to 2.31 +/- 0.25 mg dL(-1), p = 0.009) CONCLUSIONS, CLINICAL RELEVANCE: A post-operative decrease in ionized calcium was demonstrated in healthy animals, as well as an increase in ionized or total magnesium after various anesthetic protocols and surgeries. These changes, while statistically significant, do not appear to be clinically significant, as values remained within reference ranges at all times.
authors.affiliation: Section of Critical Care, Department of Clinical Studies, Matthew J Ryan Hospital of the Veterinary School, University of Pennsylvania, Pennsylvania, PA, USA. brainard@uga.edu
authors.forename: Benjamin M
authors.initials: BM
authors.lastname: Brainard
authors.forename: Vicki L
authors.initials: VL
authors.lastname: Campbell
authors.forename: Kenneth J
authors.initials: KJ
authors.lastname: Drobatz
authors.forename: Sandra Z
authors.initials: SZ
authors.lastname: Perkowski
mesh_terms: D000768:Anesthesia, General / Q000662:veterinary*; D018686:Anesthetics, Intravenous / Q000008:administration & dosage*; D000818:Animals; D002118:Calcium / Q000097:blood*; D002415:Cats / Q000097:blood / Q000502:physiology* / Q000601:surgery; D003975:Diazepam / Q000008:administration & dosage; D004285:Dogs / Q000097:blood / Q000502:physiology* / Q000601:surgery; D005260:Female; D004091:Hydromorphone / Q000008:administration & dosage; D008012:Lidocaine / Q000008:administration & dosage; D008274:Magnesium / Q000097:blood*; D008297:Male; D009919:Orchiectomy / Q000662:veterinary; D010052:Ovariectomy / Q000662:veterinary; D011184:Postoperative Period; D015742:Propofol / Q000008:administration & dosage; D013874:Thiopental / Q000008:administration & dosage
chemical_list: D018686:Anesthetics, Intravenous; D008012:Lidocaine; D008274:Magnesium; D013874:Thiopental; D003975:Diazepam; D004091:Hydromorphone; D002118:Calcium; D015742:Propofol