Uterine Lavage Mare

How to Perform Uterine Lavage: Indications andPractical Techniques

Steven P. Brinsko, DVM, MS, PhD, Diplomate ACT

Uterine lavage can be used for the treatment and prevention of uterine infections as well as anadjunctive therapy for retained fetal membranes in the broodmare. This article describes applica-tions of this technique for the practitioner. Author’s address: Department of Large Animal Med-icine & Surgery, College of Veterinary Medicine, Texas A&M University, College Station, TX77843-4475. © 2001 AAEP.

1. Introduction

Virtually every reproductive event in the life of abroodmare results in some degree of contaminationof her reproductive tract. The acts of breeding andparturition allow entry of bacteria and other irri-tants into the mare’s uterus. Mares with normaluterine defense mechanisms usually are able toovercome this contamination and return theiruterus to a healthy state without outside interven-tion. Mares with compromised uterine defensemechanisms, however, are unable to overcome thisuterine contamination and uterine infection results.

Intrauterine infusion of antibiotics is a commonmethod of treatment for endometritis. Despite thedevelopment and use of a variety of antimicrobialagents, little progress has been made in reducingthe percentage of mares that remain barren due toendometritis. This may be due, in part, to the factthat the antimicrobials are being used in a mannerthat tends to reduce their efficacy. One of the ma-jor defects described in mares susceptible to endo-metritis is impaired uterine clearance. Therefore,cellular debris and fluid, as well other inflammatoryproducts, accumulate in the uterine lumen of sus-

ceptible mares due to the mare’s inability to expelthem. Placing antibiotics directly into such an en-vironment is likely to reduce their antimicrobial ac-tivity due to binding of the antimicrobials to cellulardebris, dilution in uterine exudate, and diminishedcontact with the endometrium. Uterine lavagemay improve the efficacy of intrauterine antibiotictreatment by reducing foreign material within theuterine lumen. This is especially true for antibiot-ics of the aminoglycoside and polymixin groupswhich bind to purulent material.

Uterine lavage, used alone or in conjunction withantibiotic therapy, is believed to be beneficial in thetreatment and prevention of infectious endometri-tis. The rationale for using uterine lavage in thetreatment of uterine infections is based upon: 1)reduction of bacterial numbers and removal of exu-date from the uterine lumen, 2) enhanced physicalclearance of uterine contents by stimulation of uter-ine contractions, and 3) recruitment of neutrophilsand possibly opsonins by inducing transient irrita-tion of the endometrium. When possible, I prefer touse warm (42°C) isotonic saline, however, other bal-anced salt solutions such as lactated Ringer’s can

AAEP PROCEEDINGS / Vol. 47 / 2001 407

HOW-TO SESSION

NOTES

Reprinted in the IVIS website with the permission of AAEP Close window to return to IVIS

Proceedings of the Annual Convention of the AAEP 2001

be used and the lavage media does not have to beheated. The purpose of this article is to describethe indications and techniques for uterine lavagefound to be beneficial in clinical practice.

2. Indications, Techniques, and Materials

Treatment of Endometritis

As mentioned, performing uterine lavage prior toadministering intrauterine antimicrobials is likelyto improve response to treatment. After evacua-tion of the rectum and cleansing of the mare’s exter-nal genitalia, a sterile, balloon-cuffed catheter isplaced through the cervix into the uterus, and thecuff is inflated. One of the keys to successful uter-ine lavage is to maintain gentle caudal tension onthe tube so that the inflated cuff is in contact withthe internal os of the cervix. Once the catheter is inplace, uterine lavage is typically performed by in-stilling 1–1.5 l of a balanced salt solution by gravity-flow through the balloon-cuffed catheter. Highervolumes can be infused into mares with large, pen-dulous uteri. I prefer to distend the uterus withenough fluid so that the mare just begins to showsigns of discomfort. Distending the uterus as muchas possible helps ensure distribution of the fluidthroughout the uterus and enhances more completefluid return by encouraging uterine contraction.Large Foley catheters can be used, but I have foundtheir short length and smaller diameters to be muchless efficient than the larger bore (8-mm inner diam-eter) catheters commonly used for equine embryotransfer.a These catheters come in standard lengthsof 65, 80, and 150 cm, and tubes of different sizesand lengths are available by special order. A160-cm long fluid delivery tube with a bell-shapedendb can also be purchased from the same company.The IV bell or flared end of the delivery tube isaseptically placed over or inserted into the neck (Fig.1) of a clear glass or preferably, plastic bottle con-taining the flushing medium and manually held inplace. The bottle is then inverted and held as highas possible to allow the fluid to enter the uterus bygravity-flow (Fig. 2). Once the desired volume isinfused, the uterus can be massaged per rectum tohelp distribute the solution throughout the uterinelumen. The effluent is collected to assess volumeand clarity by simply returning the bottle to anupright position and placing the bottle on theground or at least below the level of the distendeduterus, depending on the length of tubing (Fig.3). An alternative method of delivery is to placeseveral liters of fluid into a clean rectal sleeve andinsert the end of the catheter into the open end ofthe sleeve. The sleeve is grasped tightly aroundthe tube, and then lifted and inverted as describedabove when using a bottle (Fig. 4). This processmay be repeated several times depending on thecharacter of the effluent. An appropriate antibioticcan be infused daily after uterine lavage, once theeffluent is relatively clear.

Uterine lavage is commonly performed with iso-tonic saline, however, any balanced, physiologic saltsolution can be used. I frequently use dilute(0.05%) povidone-iodine solutions as my lavage me-dium. This strength of povidone-iodine does notresult in damage to the endometrium1 and is easilymade by adding 5 ml of a stock 10% povidone-iodinesolution3 to each liter of balanced salt solution.Note that some povidone-iodine solutions are 5%povidone-iodine (0.5% available iodine) and there-fore will require 10 ml of stock solution per liter ofbalanced salt solution to yield a 0.05% povidone-iodine lavage medium. Bactericidal activity of po-vidone-iodine is enhanced when it is diluted, andhas been shown to be maintained at concentrationsas low as 0.01–0.005%.2 Therefore, except fortreatment of fungal infections, concentrations stron-ger than 0.05% are not needed. Most adverse reac-tions occur when using povidone-iodine solutionsconcentrations .1–2% which may induce severe in-flammatory responses in the equine endometrium.

Prevention of EndometritisFor mares suffering from chronic postbreeding en-dometritis despite the use of minimal contamination

Fig. 1. Plastic bottles of irrigation saline with IV bell placed over(left) or flared end placed within (right) the neck of the bottle.

408 2001 / Vol. 47 / AAEP PROCEEDINGS

HOW-TO SESSION



techniques, I have found postbreeding uterine la-vage to be particularly rewarding. A primary con-cern is the minimum time interval between breedingand uterine lavage that will not adversely affectfertility. Initial reports of successful post-breedingtherapy combining uterine lavage followed byplasma infusion delayed treatment until ovulationhad occurred. However, provided that ample timeis given for a fertilizable population of spermatozoato enter the oviducts (4 hours), performing uterinelavage as soon as possible after breeding will mini-mize the time available for microbial contaminantsto multiply and become established. Uterine la-vage performed within two hours of inseminationreduces pregnancy rate in normal mares,1 whileuterine lavage at 4 hours post-insemination has nodetrimental effect on fertility.3 The lavage proce-dure is the same as that used for treating uterineinfections with the exception that I do not infuseantibiotics into the uterus after breeding. Almostthirty years ago, data from a study presented to theAAEP showed that postbreeding infusion of someantibiotics had no beneficial effect on live foalingrate while others were actually detrimental.4

Overzealous use of antibiotics can also lead to fungal

or yeast infections, which are much more difficult toeliminate.

Postpartum MareThe primary indications for uterine lavage in thepostpartum mare are for the treatment of retainedfetal membranes, delayed uterine involution, andmetritis. When the membranes are intact, the la-vage fluid is actually instilled into the chorioallan-toic space rather than the uterine lumen, asdescribed by Burns et al. at the AAEP convention in1977 (Fig. 5).5 Uterine lavage is also useful forcleansing the uterus of debris immediately afterlengthy obstetrical manipulations and fetotomy.Distending the uterus in such facilitates palpation ofthe endometrium for lacerations and abrasions bysmoothing out the prominent endometrial folds. Inthe postpartum mare, much larger volumes (up to12 l) of fluid are used and the cervix is too dilated formost ballooned cuffed catheters to be useful in seal-ing the cervical os. Therefore, a clean stomach tubeis inserted though the cervix, and rather than grav-ity flow, a bucket and stomach pump—which have

Fig. 2. Bottle of irrigation saline connected to a large bore cath-eter by an IV bell and held high to lavage the uterus by gravity. Fig. 3. Irrigation saline bottle held upright below the pelvic

brim to allow collection, quantitation, and evaluation of lavageeffluent.


HOW-TO SESSION



been cleared of all mineral oil or other potentiallynoxious substances—are used to instill the fluid ofchoice. When tap water is used, I often add 5 ml of10% povidone-iodine solution per liter of fluid and8.5 grams of table salt per liter of fluid. When largevolumes of fluid are used, as in the postpartum

mare, 34 grams of table salt per gallon of distilledwater will yield a 0.9% NaCl solution. An easy wayto approximate 34 grams of salt in the field is tomeasure out 25 cc of salt using a syringe barrel,making sure to completely empty the syringe afterthe salt is poured into the water. Alternatively,one could fill the cap of a 60 cc syringe case to within5 mm (;3/16-in.) of the top of the cap (Fig. 6). Oneneed not be very precise and the slight hypertonicityresulting from using slightly too much salt or addingthe measured amount of salt to tap water should notbe harmful, and may in fact be beneficial.

When the mare is presented with fetal mem-branes that have not been completely expelled andplacental tags remain in the uterus distending theaffected horn(s) helps in identifying the size of theplacental tag and the degree of adherence. Lavag-ing the uterus also helps loosen the tags and stim-ulates uterine contractions to aid in the expulsion ofthe remaining membrane fragments. Cupping thehand over the end of the tube helps prevent theendometrium and tags of placenta from being si-phoned onto the end of the tube and preventing

Fig. 4. Uterine flush catheter held in a clean rectal sleeve to foruterine lavage.

Fig. 5. The Burns technique for treating a retained placenta bydistending the chorioallantoic space. (Reprinted from Burns etal. Management of retained placenta in mares, in Proceedings.Am Assoc Equine Practnr 1977;385, with permission of the pub-lisher.)

Fig. 6. Simple methods of measuring 34 grams of salt, which isadded to 1 gallon of water to make isotonic saline for uterinelavage. A syringe barrel containing 25 cc of salt or a 60 ccsyringe case cap, filled to within 5 mm (;3/16 in.) of the top of thecap.

410 2001 / Vol. 47 / AAEP PROCEEDINGS

HOW-TO SESSION



outflow. In refractory cases, the lavage can be re-peated daily followed by oxytocin (10–20 IU, IM orIV) or prostaglandin (cloprostenold; 250 mg, IM) ad-ministration. I prefer cloprostenol (Estrumatet) toLutalyset, as I have not observed the profound signsof colic associated with the latter product, whichcan be quite disconcerting in the postpartum mare.The mares are also administered appropriate dosesof systemic antibiotics and flunixin meglumine,f

which are continued for several days after the pas-sage of the membranes. After the membranes havepassed, I usually lavage the uterus at least one moretime the following day, depending on the presenceand nature of uterine discharge or the presence andcharacter of intrauterine fluid as detected by trans-rectal ultrasonography. Routine use of uterine la-vage in normal foaling mares does not appear toenhance uterine involution6 or foal heat pregnancyrates,7 therefore, I do not advocate its use.

3. Results

In more than ten years of using large volume uterinelavage for the treatment and prevention of endome-tritis as well as an aid in the expulsion of retainedfetal membranes, I have been extremely satisfiedwith the results. This has been most gratifyingwhen a valuable mare, which has been barren for anumber of years, despite the repeated use of morecommon therapies, becomes pregnant after a singlebreeding on one cycle when postbreeding uterinelavage is employed. I have also seen a number ofmares become pregnant after a single inseminationfollowed by uterine lavage four hours later, evenwhen frank pus has been lavaged from their uteriafter breeding or when urine has had to be manuallyevacuated from the vaginal vault. This is certainlynot to say that every mare that has chronic recur-rent endometritis will become pregnant using uter-ine lavage. I strongly believe however, that usinguterine lavage will greatly enhance chances of sus-ceptible mares becoming pregnant compared to an-tibiotic treatment alone, especially when thenumber of breedings per cycle are limited and min-imum contamination techniques are employed.

4. Discussion

Over the years intra-uterine infusion with a varietyof antibiotic and antiseptic solutions has been usedin an attempt to eliminate infectious endometritis inmares. These substances have ranged from agentssuch as kerosene, floor cleaners, chlorine, and iodinesolutions to potent antibiotics. Unfortunately,many of these treatments were instituted withoutknowledge of their efficacy or potential detrimentaleffects. Uterine lavage using a balanced salt solu-tion, with or without dilute (0.05%) povidone-iodine

solution, has repeatedly been shown to be a safe andeffective therapeutic technique for the treatment ofendometritis, yet it is still underutilized by manypractitioners.

Many practitioners feel that uterine lavage is tootime-consuming or the technique is too cumbersometo perform in a busy practice setting. However,using the techniques I have described, the large-bore balloon cuffed catheter and irrigation saline inplastic bottles or a rectal sleeve, uterine lavagetakes only 5–10 minutes longer to perform comparedwith other intrauterine therapies and yields worth-while results for you, your clients, and your pa-tients. A few extra minutes spent performinguterine lavage will save time in the long runthroughout the breeding season when compared tothe repeated treatments and breedings that manyproblem mares might otherwise require.

Uterine lavage is an extremely useful therapeutictechnique that can be applied to a number of repro-ductive problems in the mare. The enhancement ofthe mare’s own uterine defenses and the mechanicalremoval of uterine contaminants are its major ther-apeutic advantages over other techniques, includingecbolic agents such as oxytocin or prostagland-ins. When performing uterine lavage or any otherprocedure, in which the cervix of the problem mareis violated, employing meticulous aseptic techniqueis imperative to minimize contamination and opti-mize the chances of a successful outcome.

References and Footnotes1. Brinsko SP, Varner DD, Blanchard TL, et al. The effect of

postbreeding uterine lavage on pregnancy rate in mares.Theriogenology 1990;33:465–475.

2. Van den Broek PJ, Buys LFM, Van Furth R. Interaction ofpovidone-iodine compounds, phagocytic cells and microorgan-isms. Antimicrob Agents Chemother 1982;22:593–597.

3. Brinsko SP, Varner DD, Blanchard TL. The effect of uterinelavage performed four hours post insemination on pregnancyrate in mares. Theriogenology 1991;35:1111–1119.

4. Wearly WK, Murdick PW, Hensel JD. A five year study of theuse of post-breeding treatment in mares in a Standardbredstud, in Proceedings. Am Assoc Equine Practnr 1971;89–96.

5. Burns SJ, Judge NG, Martin JE, et al. Management of re-tained placenta in mares, in Proceedings. Am Assoc EquinePractnr 1977;381–390.

6. Blanchard TL, Varner DD, Brinsko SP, et al. Effects of post-parturient uterine lavage on uterine involution in the mare.Theriogenology 1989;32:527–536.

7. McCue PM, Hughes JP. The effect of postpartum uterinelavage on foal heat pregnancy rate. Theriogenology 1990;33:1121–1129.

aEquine Uterine Flushing Catheter, Bivona, Inc., Gary, IN46406.

bEquine Fluid Delivery System, Bivona, Inc., Gary, IN 46406.cBetadine, Purdue Frederick Co., Norwalk, CT 06850.dEstrumate, Bayer, Shawnee Mission, KS 66201.eLutalyse, Upjohn, Kalamazoo, MI 49001.fBanamine, Schering Animal Health, Kenilworth, NJ 07033.


HOW-TO SESSION



Documents

Uterine Lavage Mare