Читать книгу Complications in Canine Cranial Cruciate Ligament Surgery - Ron Ben-Amotz - Страница 27

As mentioned, Staphylococcus spp. are amongst the most common bacteria causing SSIs. S. pseudintermedius is a commensal bacteria within the normal microbiome of dogs [39]. Assessment of the animal's skin for evidence of local or distant dermatitis is recommended, to reduce the risk of contamination of the surgical site (Figure 2.1). Despite this logical recommendation, 17.5% of all animals undergoing TPLO in one study had evidence of active local or distant dermatitis. Of those with local dermatitis, 16.7% developed an SSI and 10.2% with distant dermatitis developed an SSI [27]. As there was no significant difference identified between local and distant dermatitis resulting in SSI, the risk for SSI development should not be considered lower for animals with dermatitis not affecting the direct surgical site, as anecdotally thought, and postponement of elective orthopedic surgeries with local or distant dermatitis should be considered [27].

Identifying the underlying cause of the skin disease is paramount for improving the skin barrier and reducing the risk for SSI development. Depending on the type and severity of the dermatitis, cleansing with medicated shampoos, application of topical antimicrobials or antifungals and/or systemic antimicrobials or antifungals may be required. When managing bacterial dermatitis, local to or distant from the surgical site, culture and susceptibility testing is recommended to guide antimicrobial therapy and determine if MRSP is present. While awaiting these results, empirical treatment is recommended with cephalexin (22–30 mg/kg, PO q8h) or clindamycin (11 mg/kg, PO q12h). Antimicrobials should be continued for 1 week beyond resolution of clinical signs.

Ideally, the surgical site should be free of skin lesions prior to considering surgery. In circumstances where postponing surgery is not possible, topical treatment is recommended, along with the addition of amikacin to the routine perioperative antimicrobials. When lesions are located at sites other than the surgical site, topical treatment is recommended + systemic medications as determined by the extent of the disease process. Bathing these patients with a chlorhexidine shampoo the night prior to surgery can also be considered [40].

Before skin preparation can occur, hair is clipped from the proposed surgical field to facilitate direct skin preparation and the limb is suspended (Figure 2.2). Clipping should be performed following induction of general anesthesia and not sooner due to the increased risk for SSI development [41, 42]. This risk is likely associated with the greater potential for direct skin trauma that may occur when attempting to clip hair on a conscious patient. Any microtrauma caused by rough clipping or poorly maintained clipper blades may also play a role in increasing the risk for SSI development.

Skin preparation (Figure 2.3) begins with the removal of surface dirt and oils using a neutral, nonmedicated soap as antiseptic agents are not active in the presence of organic material. Antiseptic agents are subsequently applied to reduce the bacterial load present on the skin at the time of surgery. Antiseptic agents commonly used in veterinary medicine include povidone‐iodine and chlorhexidine gluconate (Figure 2.4). These antiseptic solutions are applied to the skin using a scrub technique or a paint or spray technique. Ultimately, contact time, meaning the time the antiseptic solution is in direct contact with the skin, is the most important aspect of skin preparation. Both the World Health Organization and the Centers for Disease Control and Prevention recommend the use of alcohol‐based solutions for surgical skin preparation [43, 44]. However, in veterinary medicine, aqueous solutions of povidone‐iodine and alcohol solutions of chlorhexidine gluconate have been proven to be equally effective in reducing bacterial colony‐forming units on canine skin [45, 46]. As many different antiseptic skin preparation solutions exist, following the instructions for your chosen product to ensure adequate contact time is key for appropriate skin preparation.

Figure 2.1(a) Mild bacterial dermatitis with pustules and plaques. (b) Mild to moderate localized dermatitis without pustules or plaques. (c) Moderate generalized dermatitis. (d) Severe generalized dermatitis over the medial aspect of the pelvic limb.

Source: All photos courtesy of Dr Charlotte Pye, DACVD.

Figure 2.2 Hanging leg technique for limb suspension. (a) A piece of 2 in. tape is applied to the lateral aspect of the unclipped distal limb, with an equal amount of tape contacting the limb and extending beyond the distal aspect of the limb. (b) Using the 2 in. tape roll, a second piece of tape is placed on the medial aspect of the unclipped distal limb, mimicking the lateral aspect. The two sticky surfaces of tape are adhered together distally, with the entire tape roll remaining attached (for later use). (c) A third piece of 2 in. tape is wrapped from proximal to distal around the circumference of the unclipped distal limb. (d) The taped distal limb is covered in nonsterile Vetrap^TM. (e) Using the 2 in. tape roll that remains attached to the medial aspect of the limb, the limb is suspended from an IV pole.

The initial skin preparation is carried out using nonsterile gloves and gauze. This initial preparation is performed by alternating antiseptic soap and alcohol, three times, ensuring an appropriate total contact time. A final application of an alcohol‐based antiseptic paint may also be performed. Protection of the prepared surgical site with sterile drapes is recommended prior to transport to the operating room (OR), to decrease the risk of inadvertent contamination.

A final sterile skin preparation is subsequently performed in the OR using sterile gloves and sterile gauze. This final preparation may be performed by a nonsterile assistant wearing sterile gloves or by a sterile assistant or surgeon. The final skin preparation is performed by alternating between the antiseptic solution (Figure 2.4) and alcohol, performed three times, or using an alcohol‐based antiseptic paint alone. Whichever antiseptic soap is used for the initial skin preparation must be the same antiseptic solution used in the final skin preparation.

Figure 2.3 Skin preparation steps. Note the assistant is wearing nonsterile gloves for the initial skin preparation. (a) Using a nonmedicated neutral soap, the skin is cleansed to remove oils and debris. (b) The soap suds are removed using dry nonsterile gauze squares, working from the proposed surgical site outwards. (c) Using a chlorhexidine scrub brush (or antiseptic soap of choice on nonsterile gauze), the skin is scrubbed, working from the proposed surgical site outwards. (d) The soap suds are removed using nonsterile, alcohol‐soaked gauze squares working from the proposed surgical site outwards. Steps (c) ad (d) are repeated three times, until all soap suds are removed. (e) Finally, an alcohol‐based chlorhexidine paint is applied to the skin using nonsterile gauze squares, working from the proposed surgical site outwards until the entire field has been painted*. (f) A sterile drape is applied over the field prior to transport into the OR. Steps (c)(using an aqueous or alcohol‐based antiseptic solution in place of an antiseptic soap) and (d) (or alternatively step (e) alone) are repeated in the OR using sterile gauze and sterile gloves for the final skin preparation. *Note step (e) is optional during the initial skin preparation.