Equine Surgical Guidelines
The surgical guidelines have been developed for all veterinarians, to inform clinical decisions, in response to a survey we completed in 2016 that identified a need for widely accessible antimicrobial guidelines for surgical prophylaxis.
The results of this survey have been published and the paper can be found at this link.
We suggest you download the VPG guidelines poster, display it in your clinic and record your protocols for surgical prophylaxis in the space provided.
Measuring compliance with the guidelines, or your clinic policy, is a powerful tool in improving appropriate antimicrobial use. Periodic review of clinical records, or review of surgical checklists, with regular reporting will motivate all staff to improve appropriate antimicrobial use for surgical prophylaxis.
Aim
To provide guidance on need for antimicrobials for surgical prophylaxis to mitigate the risk of surgical site infections and where antimicrobials are indicated guidance on antimicrobial selection, timing and duration of therapy. We aim to provide guidance for common surgical conditions in dogs and cats, however some conditions may not be covered and clinicians are advised to use their best judgement in these instances.
National Research Council’s risk index for surgical infection
| Clean | Non-traumatic, uninfected. No break in aseptic technique, no inflammation encountered. Elective, closed primarily and no drain used |
| Clean-contaminated | Controlled entering of a hollow muscular viscus, minor break in aseptic technique |
| Contaminated | Open, fresh traumatic wound. Incision into a site with acute, non-purulent inflammation. Major break in aseptic technique. |
| Dirty | Pus encountered during surgery. Perforated viscus found. Traumatic wound with devitalised tissue, foreign material or faecal contamination, or of more than 4-hour duration |
Guidelines for surgical prophylaxis
| Surgical contamination level | Mitigating factors | Mitigating factors | Duration of therapy |
|---|---|---|---|
| Clean | None | None | N/A |
| Field castration1,2 | None | N/A | |
| Routine elective arthroscopy3-5 | None | N/A | |
|
Only if surgical site infection would be a major threat to the patient (ie central nervous system surgery) | No evidence, in other species preoperative only | ||
| If surgical duration >90mins6 | Penicillin & Gentamicin | No evidence, in other species preoperative only | |
| Implant | No evidence, 7 days recommended for companion animals | ||
| Clean contaminated | Penicillin & Gentamicin | Stop within 24h | |
|
Colic – no intestinal ischaemia – Ischaemic damage to GI tract |
Penicillin & Gentamicin Penicillin & Gentamicin |
Stop within 24h Some evidence for 3 days7, 3-5 days common8, 9 | |
| Contaminated | Likely anaerobic | Penicillin & Gentamicin & metronidazole | No evidence, 24-48h is common in human medicine |
| Significant bowel leakage | Penicillin & Gentamicin & metronidazole | ||
| Dirty | Choose appropriate for site of infection and likely causative agent | Treat till infection cured |
Timing of prophylactic antimicrobials
Tissue levels of antimicrobials are required at the time of first incision to confer protection from surgical site infection.
- Intravenous antimicrobials: Administer 30-60 mins prior to surgery
- Intramuscular procaine penicillin: 3.5h prior to surgery10
Tmax for individual drugs given by different routes can be used to assess optimal timing to achieve peak serum levels at the time of first incision.
Repeat dosing
Dosing interval should be measured from the time of the preoperative dose. The dosing interval can be calculated as twice the elimination half-life of the antimicrobial.
- Benzyl penicillin: 80 mins
- Oxytetracycline: 7 hours
Other factors to consider
Clip hair less than 4 hours before surgery11
Minimise number of people in surgical theatre12
Consider use of surgical safety checklist. Use of these tools has reduced surgical complications from 17% to 7% (SSIs from 5% to 1.4%).
(Based off World Health Organisation surgical safety checklist)
Other considerations
Local or regional antibiograms: If you work in a hospital that performs culture and susceptibility frequently you may consider using summarised sensitivity data (antibiogram) when selecting empiric therapy. You should consider the inherent bias in most of this data however. Most cases that have samples cultured are not reflective of the general bacteria that present in the equine community. These cases are often refractory to antimicrobials or have had previous antimicrobial therapy, thus we are testing a more resistant population of bacteria. Unless culture and susceptibilty testing is performed routinely on a large number of cases at admission/first visit, and prior to any antimicrobial therapy, this information is not useful in determining appropriate empiric therapy.
The evidence
These guidelines are designed to be evidence based and transparent. As such, we’ve provided the evidence behind our recommendations.
A literature search was undertaken in PubMed using the following search terms:
(Dog OR Cat OR Canine OR Feline) AND Surg* AND (Antibiotic OR Antimicrobial OR Infection OR Complication)
Only research papers pertaining to species other than humans, with abstracts, and papers written in English were considered. No time limit was included.
The abstracts for all returned articles were examined. Articles were included if the title or abstract suggested that either surgical site infection or antimicrobial prophylaxis for surgery were discussed in the paper. In addition, articles were excluded if the sample size was insufficient to make appropriate inferences from the study. All study designs were considered as the literature is limited.
Risk of bias was assessed using the ROBINS-I assessment tool14.
| Domains | Reason for non-inclusion | |||||||
|---|---|---|---|---|---|---|---|---|
| Confounding | Selection bias | Classification bias | Deviation from intended intervention | Missing data | Measurement | Reporting | ||
| Ahern et.al., 201015 | +++ | + | 0 | 0 | Not assessable | 0 | 0 | Paper does not describe timing of antimicrobial therapy in relation to surgery |
| Borg et.al., 20134 | 0 | 0 | 0 | NR | + | + | 0 | |
| Busk et.al., 20101 | +++ | + | 0 | NR | Not assessable | + | 0 | Paper does not describe timing of antimicrobial therapy in relation to surgery |
| Clark et.al., 200816 | ++ | + | 0 | N/A | Not assessable | 0 | 0 | Canadian bacterial isolates unlikely to be relevant to Australia |
| Dallap Schaer et.al., 20129 | ++ | + | 0 | N/A | Not assessable | 0 | 0 | |
| Durward-Akhurst et.al., 20137 | ++ | 0 | 0 | + | Not assessable | 0 | 0 | |
| Freeman et.al., 201217 | ++ | ++ | 0 | NR | + | 0 | 0 | Not significantly powered to detect difference |
| Isgren et.al., 201718 | +++ | 0 | 0 | N/A | Not assessable | + | 0 | Paper does not describe timing of antimicrobial therapy in relation to surgery |
| Kilcoyne et.al., 20132 | ++ | + | 0 | N/A | Not assessable | 0 | 0 | |
| Macdonald et.al., 19946 | +++ | + | 0 | N/A | Not assessable | + | N/A | Only data on surgical duration used, confounding to significant for other analysis |
| Mair & Smith, 200519 | + | ++ | 0 | NR | Not assessable | 0 | 0 | |
| Olds et.al., 20065 | + | ++ | 0 | NR | ++ | 0 | 0 | |
| Torfs et.al., 201020 | ++ | ++ | 0 | N/A | Not assessable | 0 | 0 | |
| Weese & Cruz, 20093 | + | 0 | + | NR | Not assessable | 0 | 0 |
References
- Busk P, Jacobsen S, Martinussen T. Administration of perioperative penicillin reduces postoperative serum amyloid A response in horses being castrated standing. Vet Surg 2010;39:638-643.
- Kilcoyne I, Watson JL, Kass PH, Spier SJ. Incidence, management, and outcome of complications of castration in equids: 324 cases (1998-2008). JAVMA 2013;242:820-825.
- Weese JS, Cruz A. Retrospective study of perioperative antimicrobial use practices in horses undergoing elective arthroscopic surgery at a veterinary teaching hospital. Can Vet J 2009;50.
- Borg H, Carmalt JL. Postoperative septic arthritis after elective equine arthroscopy without antimicrobial prophylaxis. Vet Surg 2013;42:262-266.
- Olds AM, Stewart AA, Freeman DE, Schaeffer DJ. Evaluation of the rate of development of septic arthritis after elective arthroscopy in horses: 7 cases (1994-2003). JAVMA 2006;229:1949-1954.
- Macdonald DG, Morley PS, Bailey JV, Barber SM, Fretz PB. An examination of the occurrence of surgical wound infection following equine orthopaedic surgery (1981-1990). Equine Vet J 1994;26:323-326.
- Durward-Akhurst SA, Mair TS, Boston R, Dunkel B. Comparison of two antimicrobial regimens on the prevalence of incisional infections after colic surgery. Vet Rec 2013;172:287.
- Traub-Dargatz J, George JL, Dargatz DA et al. Survey of complications and antimicrobial use in equine patients at veterinary teaching hospitals that underwent surgery because of colic. JAVMA 2002;220:1359-1365.
- Dallap Schaer BL, Linton JK, Aceto H. Antimicrobial use in horses undergoing colic surgery. J Vet Intern Med 2012;26:1449-1456.
- Uboh CE, Soma LR, Luo Y et al. Pharmacokinetics of penicillin G procaine versus penicillin G potassium and procaine hydrochloride in horses. Am J Vet Res 2000;61:811-815.
- Mayhew PD, Freeman L, Kwan T, Brown DC. Comparison of surgical site infection rates in clean and clean-contaminated wounds in dogs and cats after minimally invasive versus open surgery: 179 cases (2007-2008). JAVMA 2012;240:193-198.
- Eugster S, Schawalder P, Gaschen F, Boerlin P. A prospective study of postoperative surgical site infections in dogs and cats. Vet Surg 2004;33:542-550.
- Bergstrom A, Dimopoulou M, Eldh M. Reduction of Surgical Complications in Dogs and Cats by the Use of a Surgical Safety Checklist. Vet Surg 2016;45:571-576.
- Sterne JA, Hernan MA, Reeves BC et al. ROBINS-I: a tool for assessing risk of bias in non-randomised studies of interventions. BMJ 2016;355:i4919.
- Ahern BJ, Richardson DW, Boston RC, Schaer TP. Orthopedic infections in equine long bone fractures and arthrodeses treated by internal fixation: 192 cases (1990-2006). Vet Surg 2010;39:588-593.
- Clark C, Greenwood S, Boison JO, Chirino-Trejo M, Dowling PM. Bacterial isolates from equine infections in western Canada (1998-2003). Can Vet J 2008;49:153-160.
- Freeman KD, Southwood LL, Lane J, Lindborg S, Aceto HW. Post operative infection, pyrexia and perioperative antimicrobial drug use in surgical colic patients. Equine Vet J 2012;44:476-481.
- Isgren CM, Salem SE, Archer DC, Worsman FC, Townsend NB. Risk factors for surgical site infection following laparotomy: Effect of season and perioperative variables and reporting of bacterial isolates in 287 horses. Equine Vet J 2017;49:39-44.
- Mair TS, Smith LJ. Survival and complication rates in 300 horses undergoing surgical treatment of colic. Part 2: Short term complications. Equine Vet J 2005;37:303-309.
- Torfs S, Levet T, Delesalle C et al. Risk factors for incisional complications after exploratory celiotomy in horses: do skin staples increase the risk? Vet Surg 2010;39:616-620.