MONITORING OF POSTOPERATIVE COURSE AFTER STERILIZATION IN CATS OF DIFFERENT REPRODUCTIVE STATUS AFTER THE USE OF XYLASINE/KETAMINE ANESTHESIA

Surgical sterilization (ovariohysterectomy) is one of the most common surgical procedures in small veterinary practice because it represents the safest way to control the population of cats. Th e aim of this study is to compare postoperative recovery in three groups of cats (estrous, anestrous and gravid cats) aft er performed ovariohysterectomy using combination of xylasine/ketamine anesthesia and, on the basis of obtained data, determine whether there are some signifi cant diff erences in postoperative recovery in these three groups of cats. Th is study included 45 cats that were divided into three groups. First group consisted of 15 cats in estrous, second group consisted of 15 cats in anestrous and the third group consisted of 15 gravid cats. Ovariohysterectomy was performed in private veterinary clinic. Ane-sthetic protocol was the same for all cats, that is, combination of xylasine and ketamine at appropriate doses according to body weight. Parameters that were followed through postoperative course were appetite, body temperature, appearance of the wound and activity. Data was collected on the fi rst and third day aft er surgery. Analysis of the collected data shows relatively uniform results among groups of cats considering all followed parameters. Results in this study did not show any signifi cant diff erences in response to xylasine/ketamine anesthesia among cats of diff erent reproductive status through monitoring of postoperative course.


INTRODUCTION
Surgical sterilization (ovariohysterectomy) is one of the most common surgical procedures in small veterinary practice because it represents the safest way to control the population of cats (Stančić I. at al, 2015). Th e importance of cat population control is shown in a study (Animal Shelter Reporting Study) that reported that some 4 to 9.5 million cats are euthanized annually in USA (Kirpensteijn J., 2008). A TNR (trap-neuter-return) program for stray animal population control has been fi rst developed in Europe during 1970s, and later in the USA. Th rough this program, stray animals are humanly trapped, sterilized and medically treated and then returned to the locations where they were found. Because of the lack of information about these animals and inability to catch them again, many cats are sterilized during lactation, estrous and pregnancy. Besides the cat population control, other benefi ts of sterilization include prevention of diseases and tumors of reproductive organs.
Surgical complication rates associated with ovariohysterectomy in healthy dogs and cats have been reported to range from 6.2% to 20.6%, depending on surgeon experience. Th e majority of complications is mild and generally consists of incisional infl ammation or gastrointestinal tract upset. Incision complications are more common in larger animals and animals with longer surgery and anesthesia times (De Tora M., McCarthy J., 2011). Problems associated with incisional healing are some of the most frequently reported complications following OVH surgery. It is interesting to note that the incidence of incisional swelling, wound infection, and abdominal dehiscence has not decreased over the past 40 years (Adin C., 2011). Wide range of complications is due to diff erent defi nition of complications in diff erent studies. Most frequent complications are mild and require only care of the owner and no veterinary intervention. Th e incidence of complications is lower in younger animals, where one study identifi ed fewer complications in animals in puberty, and other 2 years of age as limit for handling sterilization without complications (Flaggella and Aronsohn, 1994; Pollari et al., 1996;Howe L.M., 1997;Romagnoli S., 2008). In a study, which included 98 puppies and 98 kittens brought to sterilization, complications due to anesthesia were 0% in both groups (Flaggella and Aronsohn, 1993Aronsohn, , 1994. In surgical practice, it is sometimes impossible to predict the duration of surgery. A number of complications that can occur during surgery can prolong duration of the procedure for even up to several hours. It is not uncommon that due to disorder of homeostatic mechanisms, recovery from anesthesia can take many hours (Spasojević Kosić Lj., Trailović D., 2011). Anesthesia of feral cats presents unique challenges. Feral cats are usually of unknown age, history, body weight, and health status. Depending on the situation, they may be malnourished, ill, or heavily parasitized. Th e wild temperament of feral cats prevents examination prior to chemical immobilization and increases the stress associated with trapping and transportation. Th e ideal anesthetic agent for feral cats would be delivered in a small volume, induce rapid immobili-zation, provide a surgical plane of anesthesia, have a predictable and suffi cient duration of eff ect, have a rapid recovery, provide adequate postoperative analgesia, and have a wide margin of safety. Xylazine is a mixed α1-and α2adrenergic receptor agonist. Xylazine contributes short duration analgesia, sedation, and muscle relaxation (Cistola A.M. et al., 2004). Th e analgesic eff ects of xylazine are not dose dependent, lasting only 20 minutes even when xylazine is administered in high doses. Th e eff ects of xylazine can be reversed with a α2-adrenergic receptor antagonist such as yohimbine. Because of the short analgesic eff ects of xylazine, yohimbine reverses the residual sedative eff ects produced by xylazine (Williams L.S. et al., 2002). Ketamine hydrochloride is classifi ed as a short-acting dissociative anesthetic that is used for chemical restraint, anesthesia induction, and surgical anesthesia in cats (Saywer et al. 1993). It is a rapid-acting general anesthetic that has signifi cant analgesic activity and lacks cardiopulmonary depressant eff ects (Plumb, 2005). In the past, ketamine has been recommended for most surgical procedures in cats, including abdominal surgery (Evans et al., 1972). Lack of complete muscular relaxation makes ketamine unsuitable as a sole anesthetic agent (Bill, 2006). Recommended doses vary depending on desired depth of anesthesia, route of administration, and the use of other anesthetics concomitantly. In cats, ketamine can be given in doses ranging from 2-33 mg/kg, although doses of 50 mg/kg have been used without fatalities (Arnbjerg, 1979;Wright, 1982). Duration of anesthesia is approximately 30 to 45 minutes (Lumb and Jones, 1973). Ketamine off ers many advantages. Th e route of administration is versatile as it can be administered subcutaneously, intravenously, intramuscularly, orally, and rectally (Wright, 1982;Hanna et al., 1988;Wetzel and Ramsay, 1998).
Considering the facts that many cats are sterilized during estrous or pregnancy, either because of TNR program or the lack of knowledge of their owners, we created this study to monitor postoperative course in cats of diff erent reproductive status during several days aft er sterilization. Th e aim of this study is to compare postoperative recovery in three groups of cats (estrous, anestrous and gravid cats) aft er preformed ovariohysterectomy using combination of xylasine/ketamine anesthesia and on the basis of obtained data determine whether there are some signifi cant diff erences in postoperative recovery in these three groups of cats.

MATERIAL AND METHODS
Th is study included 45 cats that were divided into three groups according to the appearance of their uterus in situ during surgery. First group consisted of 15 cats in estrous, second group consisted of 15 cats in anestrous and the third group consisted of 15 gravid cats. Ovariohysterectomy was performed in private veterinary clinic. Preoperative procedure included clinical examination and withholding of food and water. Th e technique of sterilization used in these cats was through ventral midline with removal of the uterus and ovaries. Anesthetic protocol included premedication with xylasine (Xylased®) at a dose of 2mg/kg i/m., and 15 minutes later intramuscular application of ketamine (Ketamidor®) at a dose of 10 mg/kg. Parameters that were followed through postoperative course were appetite, body temperature, appearance of the wound and activity. Abdominal wall was closed in two layers, peritoneum and muscles with simple continuous pattern and the skin with simple interrupted pattern with use of absorbable suture (Vicryl 3-0). On the fi rst and third day after surgery, all cats were brought to clinic for postoperative therapies -amoxicillin (Clamoxyl LA®) at a dose of 15 mg/kg.

RESULTS AND DISCUSSION
Analysis of the data collected on fi rst and second postoperative day is shown in percentages. On the fi rst day post surgery, 33.33% of gravid, 33.33% of estrous and 40% of anestrous cats did not consume any amount of food. On the third day post surgery, the results revealed that all anestrous cats had appetite while 6.67% of gravid and 6.67% of estrous cats had no appetite at all (Fig 1).  13.33% of gravid, 66.67% of estrous and 26.67% of anestrous cats had fever ( body temperature higher than 39.2 °C) on the fi st day post surgery. Situation on the third day was more uniform as it can be seen in Fig 2, where 46.67% (7) of gravid, 40% of estrous and 33.33% of anestrous cats had fever. On the fi rst day postoperatively, the highest activity rate was observed among anestrous cats, where 80% of cats were active. 66.67% of estrous cats showed activity and only 53.33% of gravid cats showed activity on the fi rst day. All estrous cats were active on the third day, while 93.33% of gravid and anestrous cats showed activity on that day (Fig 3). Monitoring of wound healing showed following results. On the fi rst day postoperatively, 93.33% of all cats presented with proper wound and only 6.67% of cats had dry wound with mild swelling at the incision site. On the third day postoperatively, proper and dry swollen wounds were observed in 44.45% and 42.22% of cats, respectively, whereas 13.33% of cats manifested wound that was infl amed, swollen and with presence of discharge. Comparative analysis among three groups of cats revealed mostly uniform results, where on the fi rst postoperative day 86.67% of gravid, 100% of estrous and 93.33% of anestrous cats had proper wounds. On the third day postoperatively, proper wounds were seen in 46.67% of gravid, 46.67% of estrous and 40% of anestrous cats (Fig 4). Perioperative mortality is extremely low in feral cats anesthetized with TKX-tiletamine/xylasine/ ketamine combination (0.3%). In a study that included 4427 sterilized cats, total mortality rate of 0.35% was found, and the mortality rate suspected to be attributable solely to anesthesia was 0.23% (Williams et al., 2002). In our study, none of the cats died due to complications of any kind aft er surgery. It can be assumed that female cats, undergoing a more invasive surgery than males, do not receive adequate duration of postoperative analgesia from a single dose of TKX (Cistola et al., 2004). Th is can be the reason why cats showed increased attention to surgical wound as the days went by. Complications of surgical incision site are most frequent complications aft er sterilization and can range from 1% to 4%. Other complications can include dehiscence, wound abscesses, anorexia, lethargy and slow recovery (Pollari, Bonnet, 1996). Complications as anorexia, lethargy and infl ammation of incision site are all seen in our study. Distribution of these complications among three groups of cats of diff erent reproductive status is very uniform and shows no signifi cant diff erences among groups. According to experience of veterinary surgeon, cats and dogs that are pregnant or in heat can be safely sterilized despite those conditions (Appel 2001, Looney et al., 2008. Results obtained in our study did not show any diff erences in response to xylasine/ ketamine anesthesia among cats of diff erent reproductive status.

CONCLUSION
On the basis of the obtained results, we can get following conclusions: 1. Monitoring of postoperative course in cats of diff erent reproductive status revealed no signifi cant diff erences in response to xylasine/ketamine anesthesia among these three group of cats 2. Postoperative complications aft er performed sterilization are more dependent on postoperative care and handling than on reproductive status of the cats