Technician Update

The Magic of the Foal

By Kendra Dostaler, RVT, VTS (EVN)

A Standardbred filly was referred to Purdue University Veterinary Hospital Large Animal Emergency Services at 3:55 pm because of a 20-hour history of colic. At the time of presentation, the filly was about 36 hours old.

The client reported that the foal was born sometime the previous morning, but the exact time and duration of parturition were unknown. The postpartum period was uneventful; the foal got into a standing position unassisted, nursed normally from the mare, and passed some meconium. The foal’s condition declined later that day, and although she was still nursing, she began to show signs of colic in the afternoon.

At approximately 7:30 pm on the evening before presentation, the owner administered flunixin meglumine to the foal. The filly’s condition remained static during the night and into the following morning. On evaluation by the referring veterinarian on the morning of presentation, the foal had abdominal gas distention; the referring veterinarian recommended probiotics and referred the patient to the Emergency Service.

On presentation to the Emergency Service, the filly was down and rolling in the trailer. She was assisted into a standing position. The mare was safely unloaded from the trailer, and the foal followed; they both walked into the hospital.

For the safety of the staff, the mare was placed into a stall as the foal was evaluated in the area in front of the stall so that the mare could see and be close to the foal during evaluation without requiring additional personnel for restraint.

On evaluation, the foal appeared alert and responsive. Body weight was 120 lb (54.4 kg) and body condition score was 5/9; temperature was 100.2°F (37.9°C), heart rate was 120 beats/min, and respiratory rate was 132 breaths/min. Lungs were clear on auscultation; cardiac examination showed no abnormalities.

Clearly painful
On physical examination, the foal appeared to be in pain; she would go down and roll when given the chance. Her mucous membranes were hyperemic; capillary refill time was less than 2 seconds. Gross examination of the integument disclosed many small abrasions over the limbs, head and tuber coxae, likely due to the rolling. Abdominal auscultation revealed increased sounds in all quadrants; the abdomen was markedly distended from gas.

Results of point-of-care bloodwork showed hemoconcentration (packed cell volume [PCV], 47%) and hypoproteinemia (total protein [TP], 4.0 g/dL), and an IgG SNAP test showed concentrations <400 mg/dL, indicating failure of transfer of passive immunity (FTPI). Peripheral blood lactate measurement was within the reference interval (0.5 mmol/L); serum chemistry panel showed a slightly elevated pH (7.46) and an elevated bicarbonate concentration (31.7 mmol/L); these results indicated a slight metabolic alkalosis, but it was considered clinically insignificant.

Diazepam and butorphanol IV were administered for analgesia and sedation prior to IV catheter placement. The filly was then folded onto a mat for further evaluation. A 16-gauge, over-the-wire, IV catheter was placed in the right jugular vein and secured in place with a 2-0 polypropylene suture on a straight needle. To preserve the integrity of the catheter, the site was covered with sterile 4 × 4 gauze and 3-inch elastic tape.

As the catheter was placed, blood samples were collected for sterile blood culture and complete blood count (CBC). The clinician elected to hold the blood culture due to the client’s financial constraints. CBC confirmed hypoproteinemia; the only other abnormal finding was leukopenia (white blood cell count, 3.5
K/µL), confirmed by a manual differential showing neutropenia (2.3 K/µL) and lymphopenia (1.2 K/µL).

Review of the blood film showed 2+ toxic neutrophils and a small number of reactive lymphocytes. Based on the FTPI, neutropenia and clinical status, the foal was given an equivocal sepsis score of 8 and diagnosed with septicemia.

Thoracic ultrasonography showed no abnormalities; abdominal ultrasonography showed the colon was distended with gas. A suspected intussusception, hypermotility of the small intestine, and stomach contents consistent with clotted milk were also observed. Her bladder was small, but the umbilicus was subjectively thickened with a 1-cm herniation. A nasogastric tube was passed to further investigate the stomach contents, which were consistent with the suspected clotted milk found on ultrasonography.

As imaging was being completed, the filly began to show more signs of pain; she was still restrained in lateral recumbency and was making every effort to roll. Additional diazepam and butorphanol were administered IV for analgesia. Because the ultrasound images provided no clear reason for her abdominal pain, an exploratory laparotomy was recommended, and the owners consented.

Exploratory laparotomy
Prior to the laparotomy, a plasma transfusion was initiated, and preoperative IV antimicrobials (potassium penicillin G, amikacin and metronidazole) and flunixin meglumine were administered. Baseline temperature, heart rate and respiratory rate were within normal limits (WNL). The fresh-frozen plasma had been thawed slowly according to the manufacturer’s directions and was adequately warmed for transfusion. Plasma was administered via a filtered blood administration set at a rate of 1 drop per 5 seconds for 5 minutes, at which time the foal’s vital signs were re-evaluated. Vital signs were WNL, and the transfusion was increased to 1 drop per second for 5 minutes.

After confirming that the filly’s vital signs were still WNL, the plasma was opened to a bolus, with reassessment of the vital signs planned for every 10 minutes thereafter. Vital signs remained WNL, and she was transferred to the surgical and anesthesia team, where her transfusion was finished while she was under general anesthesia.

At the time of induction, the filly was profoundly sedated; masked induction with 5% isoflurane was elected, and endotracheal intubation was achieved. She was placed on the surgical table in dorsal recumbency, and isoflurane inhalant at 3% on a rebreathing system was resumed. The abdomen was clipped from the xyphoid process to the pubis, and laterally to the line of the flank. The surgical site was initially prepped with 2% chlorhexidine scrub and rinsed with 70% isopropyl alcohol, with a second-phase aseptic preparation with the same products.

The surgeons then placed a sterile drape and proceeded with a 10-cm incision cranial to the umbilicus with a #10 scalpel blade. Exploration of the small intestines found a section of the small intestinal tract displaced to the right of the large colon; a volvulus of the jejunum was suspected due to the discoloration of that region. The jejunum was returned to its anatomically correct position, and it regained a healthy pink coloration. Some gas distention of the large colon was appreciated and removed with suction. No other abnormalities were noted within the abdomen. The small umbilical herniation was inverted and sutured closed.

The filly was maintained under general anesthesia on isoflurane gas for the duration of the surgery. Monitoring included electrocardiography, direct blood pressure measurements, capnography, blood gas analysis and pulse oximetry. Her vital signs remained stable for 90 minutes of anesthesia, and her recovery was uneventful.

Post-care management
The filly was returned to her ICU stall approximately 4 hours after her initial presentation to the Emergency Service. The unique stall set-up allowed the mare to have her head over the foal divide and to interact with the foal, but it prevented the foal from nursing for the immediate recovery period. The foal was placed on isotonic IV fluids with dextrose, making a 2% solution. The fluids were administered at a neonatal maintenance dosage.

At midnight, the results of the physical examination were consistent with a foal recovering normally from a surgical procedure. When the stall was approached, the foal was found to be sleeping comfortably. Body temperature was 99.1°F (37.3°C), heart rate was 92 beats/min, and respiratory rate was 32 breaths/min. Mucous membranes were pink and moist; capillary refill time was <2 seconds. Auscultation disclosed normal borborygmi in all quadrants.

The filly was assisted to stand to prevent decubital ulcers and urine scald. Blood glucose concentration was within the reference interval (110 mg/dL), and she remained fasted. Antimicrobials (potassium penicillin G and metronidazole) were administered along with the proton pump inhibitor (PPI) pantoprazole to prevent gastric ulceration.

The following morning, the results of the physical examination were nearly identical to those from her midnight examination. The filly was again assisted to stand. Blood glucose concentration was slightly decreased but still WNL (85 mg/dL). The clinician elected to hold additional supportive care, as the filly was scheduled to begin timed nursing at 8 am. Another dose of flunixin meglumine was administered at this time. Results of blood testing showed that PCV was WNL (40%), while TP (4.0 g/dL) and IgG (400-800 mg/dL) remained decreased; both issues were considered potentially correctable through another 1-L plasma transfusion.

At mid-morning, the foal was started on sucralfate, a GI protectant, to be given every 8 hours. A second 1-L plasma infusion was prepared and administered; plasma products with the same serial number were used to prevent potential negative reactions. No signs of anaphylaxis (ie, tachycardia, tachypnea, pyrexia, urticaria, or agitation) were observed with the second plasma administration.

Physical examinations and blood glucose measurements were performed every 6 hours; blood glucose levels remained WNL (149-177 mg/dL). IV crystalloid fluids were altered early in the day to include 15,000 mg of dextrose (1.5% solution), since the filly also began to nurse on the mare for 2 minutes every 2 hours.

At 2 am, the foal’s nursing time was increased to 5-minute intervals, as she was tolerating the feedings well. During this 24-hour period, urine was collected twice to assess the urine specific gravity (USG); results showed isosthenuria (USG, 1.008 and 1.010). Results of repeat CBC and serum chemistry profile were within the reference ranges, indicating a well-hydrated foal with appropriate kidney function.

The next morning, TP levels were acceptable (5.0 g/dL). Since the foal had remained stable through the night and tolerated nursing well, she was allowed to always be with the mare. She received a 500-mL bolus of crystalloid fluids with dextrose, still at a 1.5% solution, every 4 hours. Her medication regimen was maintained with 2 exceptions: omeprazole was substituted for pantoprazole for financial reasons, and metronidazole was switched from IV solution to oral tablets.

USG was stable at 1.008, and blood glucose levels remained between 101 mg/dL and 154 mg/dL for the next 24 hours. Results of physical examinations performed every 6 hours showed no abnormalities. At approximately 4 pm, the foal began displaying minor signs of discomfort, such as lying down and moving from lateral to sternal recumbency frequently and doing some half-rolls. She was pulled immediately from the mare, and IV fluids (225 mL/hr) were administered as a constant-rate infusion. A slight elevation in heart rate (100 beats/min) and respiratory rate (40 breaths/min) was observed; after 6 hours, heart rate was 80 beats/min and respiratory rate was 32 breaths/min. No additional signs of colic were appreciated overnight.

During the night, she was allowed back with the mare for 30 minutes every 4 hours. Her fluids were discontinued during that 30-minute period, and they were started again on separation from the mare. This pattern of nursing was carried on for another day, and her medications were maintained except for switching from flunixin meglumine to ketoprofen (2.2 mg/kg; 130 mg IV every 24 hours) to decrease the risk for adverse effects.

To aid milk digestion, 1 lactase tablet was given orally every 6 hours. Her fluids were also changed to crystalloids with 10,000 mg of dextrose (1% solution). Physical examinations performed every 6 hours showed no abnormalities; a spot blood glucose test showed a concentration of 112 mg/dL, indicating the foal was recovering quickly.

Four days after presentation to the Emergency Service, the foal’s medication regimen remained the same; physical examinations performed every 6 hours showed no abnormalities. PCV (35%) and TP (5.0 mg/dL) were within acceptable ranges. IV fluids were discontinued, and the foal was placed with the mare.

The next morning, a neutrophilia and minor fluctuations in electrolytes (hyponatremia, hyperkalemia, hypochloremia) were observed and attributed to discontinuation of IV fluids and adjustments to nursing from the mare full-time. Potassium penicillin G and ketoprofen were discontinued, and oral cefpodoxime was initiated due to the neutrophilia, recent surgery and resolving septicemia. Cefpodoxime was chosen for ease of at-home administration and clinician preference, given the rise in resistance to sulfa antibiotics.

Six days after presentation, the IV catheter was removed, and all medications except for cefpodoxime were discontinued. The final physical examination showed no abnormalities; the results of the blood glucose measurement showed a concentration of 162 g/dL.

The foal and the mare were both discharged, and the foal left with a positive prognosis. MeV

TEACHING POINTS
My nursing skills were put to good use for a large portion of this case, starting with setting up to receive the foal emergency and her ICU care. I also performed a visual assessment of the foal on the trailer, then safely helped her into the hospital.

I kept the foal safely restrained for the clinician during the physical examination and administration of the IV sedation. Then, I folded her down onto a mat for further evaluation. My advanced skill set was used to place an over-the-wire IV catheter in the jugular vein and to provide restraint for ultrasonography of the thorax and abdominal cavities. I continued to monitor for signs of colic, initiated the first plasma transfusion and monitored for any signs of anaphylaxis.

My next shift—and the remainder of my shifts with this case—was dedicated to postoperative care. I administered IV fluids via a pump that contained an additive, of which I calculated the amounts after receiving the prescribed dose. I also selected, set up and administered a second 1-L plasma infusion while monitoring, and I administered IV and oral medications. I checked blood glucose, urine specific gravity (USG), packed cell volume (PCV), and total protein (TP) values as indicated, and performed the second IgG assessment. Physical examinations were performed every 6 hours.

Care for the mare included milking her every 4 hours. Once the filly was able to nurse, I disconnected her IV fluids, assisted her into the stall with the mare, monitored her for the indicated nursing time, and moved her back to her stall, where I placed her back on IV fluids.

Cases involving foals are always delicate. The patient’s status can change quickly, and the patient must be monitored closely. I played a significant role in this case from start to finish, and I used my advanced neonatal skills and knowledge to ensure the foal was recovering appropriately. This was a coordinated, seamless team effort that resulted in the best possible outcome: a filly leaving our hospital with an excellent prognosis.

Related listening: in Colic in Horses, an Equine Express Podcast episode, Dr. Louise Southwood discusses how earlier referral has improved outcomes for horses with surgical colic.