Companion Animal Surgery 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

SURGERY CLASSIFICATION	DESCRIPTION	EXAMPLES
Clean	Non-traumatic, uninfected. No break in aseptic technique, no inflammation encountered. Elective, closed primarily and no drain used.	Eg. Routine spey or castration Exploratory laparotomy (not entering viscus)
Clean-contaminated	Controlled entering of a hollow muscular viscus, minor break in aseptic technique	Eg. Exploratory laparotomy for foreign body removal, cystotomy (no abdominal contamination)
Contaminated	Open, fresh traumatic wound. Incision into a site with acute, non-purulent inflammation. Major break in aseptic technique.	Eg. Cystotomy/laparotomy with significant abdominal contamination, pyometra, closure of contaminated traumatic wound (<4h duration).
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.	Eg. Peritonitis, necrotic traumatic wound (>4h duration) undergoing primary closure.

Guidelines for surgical prophylaxis in dogs and cats

Surgical contamination level	Complicating factors	Likely Pathogens	Antimicrobial recommendation	Duration of therapy	Level of evidence
Clean	None1		N/A	None	Strong
	If surgical site infection would be a major threat to the patient (ie central nervous system surgery) Hypotension Surgical duration >90 mins3,4 Obese dogs5 Endocrine disorder6 Bacterial dermatitis		Amoxycillin or 1st generation cephalosporin	Stop within 24h*2	Medium
	Implant1,7	Orthopaedic: Staphylococcus intermedius	Amoxycillin or 1st generation cephalosporin	Perioperative only**7
Clean contaminated	Gastrointestinal	Coliforms, anaerobes if caudal GI tract	Amoxycillin or 1st generation cephalosporin	Stop within 24 hours*	Medium
Contaminated	Pyometra, prostatic abscess	E. coli, Streptococcusspecies, Anaerobes	Amoxycillin or 1st generation cephalosporin & gentamicin & metronidazole	No evidence, 24-48 hours is common in human medicine	Weak
	Significant bowel leakage	Coliforms	Amoxycillin & gentamicin	No evidence, 24-48 hours is common in human medicine	Weak
Dirty			Choose appropriate for infection (ideally based on culture and susceptibility testing)	Until clinical signs resolve	Weak
Dental	None	None	None	N/A	Medium
	Geriatric patients Heart disease Systemic illness Immunosuppression		Bacteraemia expected for duration of procedure8, 9. If cannot tolerate this: clindamycin or amoxycillin.	Stop within 24 hours*	Weak

* Stop within 24 hours indicates administration prior to and during surgery, and doses after surgery up till 24 hours. Inter-dosing interval after surgery is described below.

**Perioperative only indicates administration prior to and during surgery, but no further doses after surgery

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

Subcutaneous amoxycillin / clavulanate: 2 hours prior to surgery

T_max 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 during surgery can be calculated as twice the elimination half-life of the antimicrobial. For example, the dosing interval during surgery for common intravenous antimicrobials used in surgery for dogs and cats are:

Cefazolin: Maintains concentrations above MIC for common skin pathogens (Staphylococcal  & Streptococcal species) for 4 hours (10), however 2 hourly administration (twice elimination ½ life) may be required for E.coli. (11)

Amoxycillin: 2 hours

Following surgery, if antimicrobials continue to be indicated, the dosing interval returns to that used for non-surgical indications.

Other factors to consider

Clip hair less than 4 hours before surgery⁴

Minimise number of people in surgical theatre⁵

Consider use of surgical safety checklist. Use of these tools has reduced surgical complications from 17% to 7% (SSIs from 5% to 1.4%).¹¹

(Based on World Health Organisation surgical safety checklist)

A special mention – surgical treatment of Cranial Cruciate Ligament disease

• Tibial tuberosity advancement (TTA): Peri-operative prophylaxis only, no evidence for post-operative therapy¹².
• Tibial plateau leveling osteotomy (TPLO): Peri-operative prophylaxis only^{13, 14}. Studies that have shown reduced post-operative surgical site infections have had protocols that were unlikely to lead to necessary serum antimicrobial levels at the time of the first incision¹⁵, or did not report timing and in which antimicrobial therapy was given at the surgeons discretion^16-18 thereby introducing unacceptable confounding bias. Careful attention should be paid to timing of prophylactic antimicrobial therapy.
• TightRope: Peri-operative prophylaxis only¹⁴.

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.

In addition, guidelines from other professional organisations (restricted to those written in English) were reviewed and in particular, the reference lists of these guidelines. Only evidence-based recommendations were considered in constructing these guidelines. The guidelines were created by consensus by the development group.

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.

Research assessing risk of surgical site infection (SSI)

RESEARCH SETTING	SSI	TYPE OF SURGERY	COMMENTS
Private practice, Canada19	1-4%	OVH & castration
University practice20	12.70%	OVH
University practice21	2.50%	Elective
University practice2	3.60%	CCL
University practice22	3.90%	CCL	Perioperative antimicrobials did not influence rate although only small number that didn’t get antimicrobials
University practice4	1.70%	Minimally invasive
University practice4	5.50%	Open surgery	Perioperative antimicrobials did not influence rate
University practice21	2.50%	Clean
University practice21	4.50%	Clean-contaminated
University practice21	5.80%	Contaminated
University practice21	18.10%	Dirty
University practice23	4.50%	Clean
University practice3	0.80%	Clean
University practice24	3.50%	Elective joint surgery
University practice25	9.0%	External fixation in cats

OVH, ovariohysterectomy; CCL, cranial cruciate ligament syndrome

Quality of the evidence (Risk of Bias assessment)

	Domains							Reason for non-inclusion
	Confounding	Selection bias	Classification bias	Deviation from intended intervention	Missing data	Measurement	Reporting
Aiken et.al. 20177	0	0	0	+	0  short and medium term ++ long term	0	0
Andrade et.al. 201626	+++	+	0	N/A	0	0	0	Risk of confounding too high
Beal et.al., 200027	+	+	0	NR	0	+	0
Beever et.al., 201725	+	0	0	N/A	+	+	0
Bergstrom et.al., 201611	+	+	0	0	Not assessable	+	0
Billings et.al., 199024	+++	++	0	0	Not assessable	Not assessable	N/A	Risk of confounding too high
Bristow et.al., 201528	++	+	0	NR	Not assessable	Not assessable	N/A	Did not report length of antimicrobial therapy
Bowersock et.al., 20008	0	0	0	0	0	0	+
Casale & McCarthy, 200922	+	++	0	N/A	NR	+	N/A
Cook et.al., 201014	+	+	0	0	Not assessable	Not assessable	0
Eugster et.al., 20045	0	0	0	N/A	+	+	0
Fitzpatrick & Solano, 201015	+++	+	0	0	Not assessable	+	0	Pre-operative antimicrobial therapy not given early enough
Frey et.al., 201018	+	++	0	0	Not assessable	Not assessable	N/A	Did not report length of antimicrobial therapy
Gatineau et.al., 201116	+++	+++	0	N/A	Not assessable	Not assessable	0	Did not report timing of antimicrobial therapy, post-operative therapy given at the surgeon’s discretion
Heldmann et.al., 199923	++	+++	0	0	Not assessable	Not assessable	N/A	Did not describe antimicrobial therapy
Jardel et.al., 201129	+++	+++	0	0	Not assessable	Not assessable	N/A	High risk of confounding and selection bias
Nazarali et.al., 201430	++	+++	0	N/A	NR	0	++	High risk of confounding, selection and reporting bias
Mayhew et.al., 20124	++	++	0	N/A	+	0	N/A
Nicoll et.al., 201431	0	0	0	N/A	0	0	N/A
Nicholson et.al., 20026	++	++	0	N/A	NR	0	+++	Limited data in paper to verify results. No reporting on effect of antimicrobials
Nieves et.al., 19979	0	0	0	N/A	0	0	+
Pacchiana et.al., 200317	+++	+	0	N/A	Not assessable	Not assessable	0	Antimicrobial therapy given at the discretion of surgeon and not included as exposures variable
Pratesi et.al., 201532	0	0	0	+	0	0	+++
Pollari & Bonnett, 199618	0	+	+	N/A	0	+	0
Solano et.al., 201533	+++	+++	0	NR	NR	0	+	Confounding and selection bias too high
Stauffer et.al., 200613	0	+	0	N/A	NR	0	N/A
Turk et.al., 20151	0	0	++	N/A	NR	++	0
Vasseur et.al., 19853	0	0	0	NR	N/A	0	0
Vasseur et.al., 198821	++	0	+	N/A	NR	+	N/A
Weese & Halling, 20062	+	+	0	N/A	Not assessable	0	N/A
Yap et.al., 201512	+	+	0	N/A	Not assessable	Not assessable	0

Risk of bias was assessed using the ROBINS-I assessment tool²⁸.

NR, not reported; N/A, not applicable

Manuscripts in red were not considered for recommendations.

Range 0 (no bias detected) to +++ (major bias detected)

References

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