Kristy Broaddus Bite Wounds: Why are they so hard to manage? Kristy Broaddus, DVM, MS, DACVS VESC Richmond VA Michigan State DVM Auburn University internship and surgery residency Oklahoma State University i faculty Richmond, Virginia private practice Virginia Veterinary Conference 2016 Saturday February 27 8:00-8:55a Bite Wounds General Common injury in small animal practice Account for approximately 10 15% of all trauma cases Ranges from minor to life threatening Iceberg effect Two stage theory Bite Wounds Outline Initial management of wounds Antimicrobial therapy Cavity wounds Monitoring Surface Small seemingly benign puncture wounds Deep tissues Intense damage Infection Morbidity Mortality 1
Dog teeth are most dangerous for physical damage Acute angle induces tearing Force of 450psi Tissue avulsion occurs Molars crush Iceberg effect Cat Bites Sharp pointed teeth straight Deep puncture Innoculate tissue with oral flora, environment and victim s skin Consequences Disrupted blood supply Dead space Injection of hair and bacteria from biter, environment, victim Skin is avulsed off of subcutaneous tissue Subcutaneous tissue avulsed off of muscle Muscle is avulsed off of bone Blood supply is disrupted Dead space is created Oral flora is injected in all layers Initial injury looks benign Surface injury appears minor Below the skin = havoc! Don t be fooled Can develop in to SIRS 2
Epidermis outer stratified epithelium (most superficial layer) Dermis deep to epidermis Cutaneous capillary network Lymphatics and nerves Hair follicles and glands Primary vessel (direct cutaneous artery) originates from aorta Branches at panniculus to become cutaneous vascular system Divides into deep, middle and superficial plexus Run parallel to skin Extensive collateral system Skin protective mechanisms to injury Elasticity of skin from collagen No firm attachments to muscle, bone or fascia Extensive collateral blood supply Risk of (delayed) loss of skin: directly lacerate direct cutaneous vessels pull and stretch vessel = thrombosis Hypodermiscan physicallyseparatefrommuscle separate muscle, severing the vessel Death of a skin flap will result from loss of direct cutaneous vessel and collateral supply 1 to 7 days to declare itself Risk of (delayed) loss of skin: Infection thrives in the face of tissue necrosis and compromise Diminished blood supply with innoculum of bacteria Up to 7 days for a wound to declare itself Large window of time Prepare owners for second phase of therapy Even if a drain is placed and surgery performed, wounds may still fail! 3
INITIAL MANAGEMENT OF WOUNDS Protect wounds during patient stabilization Use Gloves!!!! Avoid compounding with nosocomial infections Cover wounds during stabilization, sterile lube Treat wounds Clip Clean Explore WEAR GLOVES!! Doctors Technicians Assistants Anyone touching the patient Decrease nosocomial infections Exam gloves Preparation of wound Examine patient for wounds Dogs: Face and neck Cats: hind quarters If picked up off of the ground may see thoracic and abdominal wounds Internal injuries if shaken Kidneys susceptible to bites over lumbar region Protect patient Routine stabilization as directed Treat life threatening issues Protect wound Cover the wound Hemorrhage control Initial protection Prevent additional contamination & desiccation 4
Fill wounds with sterile lube Keeps debris, hair, scrub out of wounds Extensive clipping of hair Visibility and cleanliness Scrub surrounding skin with chlorhexidine Avoid actual wound bed Lidocaine for additional analgesia Examine woundfor depth, extent Soft catheter Gentle flushing with catheter tip syringe using isotonic solution such as saline Open and/or place drains in large regions of disruption Open pockets Remove devitalized tissue Fat, skin, muscle Tack healthy tissues in place Rapidly absorbable suture Culture? Drain or leave open Tie Over Bandages Tie Over Bandages 5
Drains: Passive and Active Do not drain through main incision site Consider long subcutaneous tunnel Do not compromise future surgeries with exit site Clip and clean around exit site Gravity dependent with passive Use sterile technique when emptying/handling Latex, soft, collapsible, radiopaque, rubber tube Drainage occurs on the outside of tube MOA is combination of capillary action, gravity, overflow, fluctuation of pressure in the space occupied by drain Penrose Drain Selection Penrose Drain Passive Penrose Eliminates fluid accumulation in tissue dead space Improve vascular supply, phagocytic cell access and bacterial opsonisation Prevents fluid from accumulating beneath a wound Prevents premature wound closure, allows continued drainage Drain should be placed in deepest part of wound with egress in gravity dependent region Egress hole should be large enough Do not fenestrate Place absorbent dressing over exit Collects exudate to quantify Barrier to environmental contamination Avoid excoriation of skin from drainage Active Jackson Pratt Negative pressure grenade pulls fluid out of the wound exits a location distant from the wound secured with a purse string and Chinese finger trap suture Drains Jackson Pratt Empty reservoir q6h Air tight cavity Use gloves and sterile technique Can use petroleum around stoma if leak suspected Active Drains 6
Drains The J P drain Flat fenestrated white or clear tubular silicone drain tube that is implanted into the wound Connected to clear tubing that exits the wound and terminates in the reservoir/grenade Multiple sizes Negative pressure is generated by closing the reservoir cap while compressing it Warning! Two stage process Initial injury Tissue declaration up to 7 days Prepare owner for additional procedures if early in injury Cassie: Severe bite wound Cassie: Severe bite wound 12 y FS golden retriever Attacked at home by housemate when owner not present Laceration over ear Bruising of dorsal neck ER sutured tissues back in place and allowed wound to declare itself Cassie: Severe bite wounds 7
Antimicrobial therapy Antimicrobial therapy Dog bite wounds: Pasteurella multocida Streptococcus sp. Staphylococcus sp. Enterococcus Majority are polymicrobial Anaerobic and aerobic spp. Cultured in majority No clear recommendations in literature High risk Fresh full thickness wounds with surrounding crush injury Cellulitis avulsion Decreased immune resistance from endocrinopathies or sepsis Chronic wounds Wounds where full and complete debridement is not possible Wounds involving body cavities Antimicrobial therapy Because polymicrobial potential, it is impossible to recommend a fool proof therapy Ideally, we would culture every wound Cover gram negative and positive Cover anaerobes Amoxicillin/clavulonic acid +/ fluroquinolone ** less concern if leaving wound open for topical therapy after debridement sugar and honey! Culture if not making progress Abdomens must be explored Most chests benefit from exploration Especially if defects noted Lavage Reconstruction External support Body Cavity Wounds 8
Monitoring bite injuries Prepare owners for potential Failure of flap/closure Need for second surgery Healingby second intention Need for culture Monitoring bite wounds Check wounds at least once weekly Wounds with drains should be checked daily to EOD ideally First 7 days is most critical ii lfor wound declaration Death of blood supply Tissue declaration Infection development Conclusions Questions?? Prepare for the worst Explore wounds Use drains when necessary Proper antibiotic therapy Warn owner of second stage of treatment 9