The Modern Equine Vet
January 2024
Vol 14 Issue 1 2024
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Technician Update

Stabilizing a Foal Born Via Emergency Cesarean-Section

By Ali Harman, RVT, VTS-EVT

In February 2023, a 7-year-old Friesian mare presented to the William R Pritchard Veterinary Medical Teaching Hospital (VMTH), at the UC Davis, School of Veterinary Medicine, for evaluation of fever and diarrhea lasting 3 days. Differential diagnoses for the mare included a large colon impaction or right dorsal displacement but a differential for the fever (102° F) was not immediately known. The mare was transferred to the isolation unit for treatment of enterocolitis and endotoxemia.

Upon presentation, the mare was approximately 320-330 days in foal based upon the owner’s estimation as a last breeding date was not provided. A consult with the equine theriogenology service revealed a strong and active fetus with a heart rate of 88 beats per minute (bpm) (reference range [RR] 80-120 bpm in utero), combined thickness of uterus and placenta (CTUP) within normal limits at 0.8 mm, RR 0.8-1.0 cm) and a tightly closed cervix.

After 48 hours, the mare’s condition declined, and her pain could not be managed medically. A repeat rectal examination was more compatible with a right dorsal displacement of the colon. The foal was also showing symptoms of stress, such as decreased activity on ultrasound and bradycardia (60 bpm). The owner elected surgical delivery of the foal and exploration of the cause of the mare’s colic symptoms.

A black colt weighing approximately 50 kg was successfully delivered by the surgical team and was immediately transported to a room adjacent to the surgical suite for evaluation and treatment.

Upon delivery, the foal appeared to be anesthetized due to the surgical medications given to the dam. The foal was bradypneic with a respiratory rate of 20 breaths per minute (brpm) (RR 60-80 brpm immediate post-foaling), bradycardia with a heart rate of 60 bpm (RR 60-120 bpm immediately post-foaling) and an oxygen saturation (SpO2) of 90%. The patient’s mucous membranes (MM) were mildly cyanotic; no adventitious lung sounds were appreciated on auscultation, and the rectal temperature was 99.9° F (RR 99.5-102.5° F).

Immediately after delivery, an 8 mm endotracheal (ET) tube was passed and placement in the trachea was confirmed via auscultation of the lungs and the use of an end tidal carbon dioxide detector. Oxygen was administered via the endotracheal tube at 10 L/min. After 1 minute the foal began spontaneous respiration with a rate of 60 brpm and an SpO2 of 94%. The patient’s temperature remained normal, and a proper body temperature was maintained with a blanket warmer.

While the ET tube was being placed, the left jugular vein was clipped and prepped using aseptic technique for placement of an emergency access intravenous catheter. An over-the-needle 16 gauge by 3½ inch catheter was placed in the left jugular vein and sutured in place with 2-0 prolene.

A venous blood sample was obtained for analysis 3 minutes after delivery which revealed a respiratory acidosis (blood pH 7.260, RR 7.32-7.42 pH units) and a partial pressure of carbon dioxide (pCO2) of 46.5 mmHg, RR 38-42 mmHg), hyperkalemia (5.0mEq/L, RR of 3.1-5.0 mEq/L), azotemia (creatinine 10.0 mg/dL, RR less than 2 mg/dL), hyperlactatemia (10 mmol/L, RR <2 mmol/L) and leukopenia (3,460/uL, RR 8000-10,000 WBC per uL).

A 20 mL/kg bolus of crystalloid fluids were given with 50 mL of dextrose 50% added for a final concentration of 2.5% dextrose. After the bolus, a second liter of fluids with a final concentration of 5% dextrose was administered at approximately 10 mL/kg/hr. The foal’s heart rate increased to 80 bpm but respiration was still being assisted by the ET tube; SpO2 only measured at 96%, so oxygen delivery was increased to 13 L/min.

Nine minutes after delivery, the foal began deliberately moving its head and its vitals were stable (84 bpm, 60 brpm, and 100° F) so the ET tube was removed. Oxygen supplementation was transitioned to intranasal delivery through a 14 French Airlife catheter in the left nostril. The foal was then maintained at a rate of 10 L/min for the remainder of his stabilization. The foal made multiple attempts to stand but was kept in sternal recumbency by the clinical team as evaluation of the cuboidal bones had not yet been performed.

Umbilical care was initiated 20 minutes after delivery. The umbilicus was rinsed using a mixture of sterile water and chlorhexidine (1 part chlorhexidine to 3 parts sterile water) and the structure was clamped using straight Kelly forceps. The first clamp was placed 5 cm distal to the abdomen and a second clamp was placed 2.5 cm distal to the first clamp; 2 minutes later the umbilicus was cut between the 2 clamps. The structure was again rinsed with the chlorhexidine mixture.

Due to high risk for sepsis, the foal was started on antimicrobial therapy including sodium ampicillin (30 mg/kg, slow IV) and ceftiofur sodium (5 mg/kg, IV). To support immune and muscle function, vitamin E and selenium (E-SE 2.5 mg) was administered intramuscularly (IM) in the right semimembranosus muscle after cleaning the area with chlorhexidine and alcohol. A 0.3 mg/kg dose of hydrocortisone was given intravenously as a central nervous system stimulant.

Placement of a long-term catheter was performed in the right jugular vein. An area over the right jugular vein was clipped and prepped using aseptic technique and a 16 gauge by 20 cm over-the-wire catheter was successfully placed and sutured in place with 2-0 ethilon.

Forty minutes after delivery, a repeat blood gas analysis was performed. The hyperkalemia resolved (3.6 mEq/L) and the other parameters previously mentioned were showing response to treatment (pH 7.274, creatinine 8.4, mg/dL and lactate of 7.5 mmol/L). A commercial pediatric enema was administered via rectum, which did not yield any fecal output.

An indwelling nasogastric tube (14 French by 125 cm) was placed in the left nare and placement in the stomach was confirmed radiographically. The foal was administered 120 mL of donor colostrum.

Lateromedial and dorsopalmar radiographs were taken of both carpi and lateromedial and dorsoplantar views were taken of both tarsi to evaluate the degree of ossification of the cuboidal bones. Review of these studies revealed adequate ossification of both the carpi and tarsi. Although the foal was physically able to stand, the patient was not yet coordinated enough to walk, and his transpiration back to isolation was facilitated with a forklift.

The continued treatment plan for the foal included physical exam and blood gas analysis every 4 hours, continuing ceftiofur sodium at 5 mg/kg, IV every 6 hours, sodium ampicillin at 30 mg/kg, slow IV every 6 hours, constant rate infusion of crystalloid fluids at 3 mL/kg/min, intranasal O2 therapy at 5 L/min, sucralfate 1 gram, orally every 12 hours, and hydrocortisone 0.3 mg/kg IV every 6 hours. Feeding orders included checking for reflux every 2 hours and feeding the foal 400 mL mare’s milk (from frozen milk bank) via nasogastric tube if reflux measured less than 50 mL. The foal was permitted to stand every 2 hours.

Nine hours after delivery the foal became tachypneic with a respiration rate of (60 brpm), an increase in pCO2 at 58 mmHg; due to hypoventilation, intranasal oxygen was increased to 7 L/min. One liter of high gamma plasma (EquiPlas Plus Equine IgG) was given at a rate of 3 mL/kg/hr (IV fluid therapy was discontinued during this time, and dextrose 50% was administered at 3 mg/kg/min during plasma administration).

At 17 hours old, the colt had not yet urinated and was given a 0.15 mg/kg dose of furosemide IV, after which the foal was able to produce urine while in lateral recumbency. He was then unable to pass urine on his own. The penis was prepped using aseptic technique and a closed urinary catheter system was placed.

The foal responded well to treatment within the first 24 hours. The single dose of frozen colostrum and hyperimmune plasma transfusion provided an adequate response and the foal’s immunoglobulin G levels measured greater than 800 mg/dL. Blood gas values continued to improve with the hyperkalemia resolved (3.8 mEq/L) and the hyperglycemia, hyperlactatemia and azotemia resolving with values of 126 mg/dL, 5.8 mmol/L and 6.49 mg/dL respectively. The respiratory acidosis persisted.

As the owners were unable to provide a last breeding date, the true gestational age of the foal was unknown. The foal displayed signs of prematurity/dysmaturity including floppy ears, laxity in all 4 limbs and excessive eponychium. Fetal cortisol levels increase prior to parturition (RR 12-14 μg/dL) and decline to steady for the first five days of life to 5-7 μg/dL. The patient’s cortisol levels were measured 24 hours after delivery and were found to only measure at 2.4 μg/dL, which confirmed that the patient was premature.

After that point, the foal’s status began to decline, and he showed an increasing number of symptoms consistent with Neonatal Maladjustment Syndrome (NMS). Symptoms included generalized weakness, reduced ventilation, gastrointestinal dysfunction and depression. These signs signs are associated are associated with the normal pathophysiology of NMS, which was an anticipated complication due to the nature of the foal’s delivery. NMS is often seen in foals that have experienced an hypoxic ischemic event-such as respiratory depression seen with anesthetic agents. The respiratory acidosis and hyperlactatemia were all indicative of the foal experiencing a hypoxic event during delivery. The foal was also at an increased risk for NMS due to the inflammatory response seen in the dam (dam had a serum amyloid A level of 744 μg/dL (RR 0-20 μg/dL). As the foal was born alive, direct examination of the CNS was not available, so this syndrome is diagnosed symptomatically.

The foal did experience several setbacks and required additional care. Respiratory (doxapram, 0.01 mg/kg/min, CRI) and CNS stimulants (hydrocortisone, 0.3 mg/kg, IV every 6 hours) were provided intravenously. The foal failed to pass meconium and was treated with an acetylcistein retention enema, which was productive. IV fluid therapy continued with crystalloid fluids and dextrose 50% CRI at 1 mg/kg/min. The development of pneumonia was treated with nebulization with amikacin sulfate and sterile water.
The foal responded positively to all treatments and supportive therapy and was discharged at 9 days of age.

Most foals delivered via c-section at the VMTH are non-viable and are typically the result of a dystocia. Receiving a viable neonate was an excellent exercise in emergency medicine, neonatology and understanding of the treatment that would be needed.

Monitoring and management of a critical equine neonate requires a specialized skillset and the ability to note any change in the foal’s condition because they are prone to rapid declines.

As a result of the high level of care this foal received, it was discharged at 9 days of age, where foals of similar condition referred in from outside facilities have an average hospitalization stay of 14 days. MeV

Teaching Points
As the only technician available for the procedure, I wore many hats to help ensure the success of the patient.

The first challenge that I faced was preparing for receiving the foal. Most of the surgical delivery of neonates occurs in a surgical suite that is adjacent to the neonatal ICU (NICU).

Because the dam had been housed in isolation, and we had not yet received laboratory results, results about infections, yet, the procedure about infections, the procedure had to be performed in a different area of the hospital, so we did not contaminate the NICU.

Due to the change in venue, all the equipment, supplies and medications that were needed for the foal had to be moved to a new location. This required that I understood the delivery process, possible complications and treatments for such complications to have the needed items close at hand. Additionally, as the procedure was an emergency, there was only 20 minutes available to gather and set-up the receiving area.

After delivery, it was my responsibility to prepare the site for catheterization, taking notes of times and treatments, and initiating treatments such as fluid and antimicrobial therapy.

A key feature to the success of this delivery, was clear and productive communication among staff. There were multiple services working to perform the procedure (anesthesia, theriogenology, medicine and surgery), which required that all staff members be aware of the chain of events and expectations for the procedure.

For the medicine team receiving the foal, it was clearly communicated who would be responsible for specific tasks to ensure that all needed areas of support were covered and treatments could be initiated simultaneously.

The open line of communication also allowed for collaboration within the medicine team. The clinician placing the endotracheal (ET) tube encountered difficulty in initial attempts at placement. Being experienced with placing ET tubes, I suggested a change in positioning of the patient’s head to allow easier access to the trachea. The change in position was accepted, and the ET tube was easily placed.

Understanding the disease processes the foal faced, understanding laboratory values and careful monitoring of the foal allowed me to quickly communicate any concerns regarding the patient.

About the Author
Ali Harman earned a Bachelor’s of Science degree in Equine Sciences from UC Davis in 2009. She continued to pursue a career in the equine veterinary industry as a technician. She gained her RVT in 2017, and most recently her Veterinary Technician Specialty in Equine Veterinary Nursing. She is currently the Large Animal Critical Care Assistant Supervisor at UC Davis.

For more information:
Kimura Y, Haneda S, Aoki T, et al. Combined thickness of the uterus and placenta and ultrasonographic examinations of uteroplacental tissues in normal pregnancy, placentitis, and abnormal parturitions in heavy draft horses. J Equine Sci. 2018;29(1):1-8.
https://www.jstage.jst.go.jp/article/jes/29/1/29_1723/_article

Long A, Nolen-Walston R. (2020). Equine inflammatory markers in the twenty-fFirst century: a focus on serum amyloid A. Vet Clin North Am Equine Pract. 2020;36(1):147-160. https://www.sciencedirect.com/science/article/pii/S0749073919300744?via%3Dihub

Nagel C, Aurich J, Aurich C. Determination of heart rate and heart rate variability in the equine fetus by fetomaternal electrocardiography. Theriogenology. 2010;73(7):973–983. https://www.sciencedirect.com/science/article/abs/pii/S0093691X10000142

 

The mare at the start of the surgical procedure.

The patient is seen receiving colostrum by an indwelling nasogastric tube. The colostrum is allowed to pass through the tube via gravity

The image on the left shows radiographs being taken of the carpi to evaluate ossification of the cuboidal bones.

A staff member waits for the foal to be brought to the isolation room.

Excessive eponychium was noted on the hooves which can be correlated to prematurity or dysmaturity.
Images courtesy of Ms. Harman