Intensive care management under field conditions; what we really can do?

Equine NICUs have greatly improved our knowledge and understanding of the normal and abnormal physiology of the equine neonate, resulting in an improvement in our ability to successfully treat the critically ill equine neonate and save lives. We have also been able to translate many treatments from the referral hospital to the field with good success for the practitioner.

The Sick Foal

The kidney is a target for injury in these patients and it is not unusual for renal compromise to play a significant role in the demise of these foals. The urine of normal newborn foals is quite dilute, reflecting the large free water load they incur by their milk diet. Aminoglycoside toxicity occurs in the equine neonate and will exacerbate or, at the least, complicate the management of renal failure originally due to primary hemodynamic causes. In general sick foals can suffer from a variety of problems associated with abnormalities within the gastrointestinal tract. Foals with other ailments, peripartum adverse events or failure of passive transfer of maternal immunity (FPT) are also susceptible to secondary infection. Treatment of recognized infection is necessary and antimicrobial treatment should be broad-spectrum. Any acute deterioration in the condition of a compromised foal indicates a need for further evaluation for possible sepsis.

Practical Solutions to Common Problems of the Foal

The equine practitioner may be faced with management of fairly ill neonatal foals without access to referral facilities, either due to location or financial restriction placed by the owner. The following are some suggested solutions to problems that may be encountered by the practitioner under these conditions.

Long-term Intravenous Access:

In these cases, placement of ‘over the wire catheters’ provides the best solution. The catheters are generally made of non-thrombogenic materials and are more pliable, making them less likely to clot or to break Placement of these catheters is more challenging than over the needle catheters, but with practice placement becomes straightforward.

Catheterization is performed most readily in recumbent foals but can be performed in standing foals. Having sufficient help available is important, as good restraint of the patient is necessary. If help is not readily available, small doses of diazepam (2-5 mg per foal, IV) can make the process easier. Xylazine should be avoided in very young foals as it can cause transient hypertension. Catheters should be sutured in place. These catheters should be flushed at least 4 times daily. There is generally no need to place a bandage or any other type of protection over the catheters.

Tube feeding:

Foals able to tolerate enteral feeding but too weak to suck properly from the mare, or any foal without the ability to suck, may benefit from placement of a long-term enteral feeding tube. The tubes are well tolerated by foals and they can learn to suck from the dam around themFeeding should always be performed under gravity flow only. It is ideal to pass a large bore nasogastric tube to check for reflux before placing these tubes as a foal with significant gastric fluid accumulation, or blood tinged gastric fluid, should not be fed enterally until this is resolved. Feeding should initially aim at providing milk or milk replaced at about 10% of the foal’s body weight per day. This is divided into 12 feedings given at 2 hour intervals. Once the feed is administered the tube should be flushed with a small volume of water ad recapped. Foals should be standing or in sternal recumbency during the feeding and should remain in that position for at least 5 minutes once feeding is completed.

Fluid Therapy in the Field:

Fluid therapy should be conservative during postpartum resuscitation, as the newborn foal is generally not volume depleted unless excessive bleeding has occurred. If intravenous fluids are required for resuscitation administration of 20 ml/kg of a non–glucose-containing polyionic isotonic fluid over 20 minutes (about 1 L for a 50-kg foal), The foal should be reassessed after the initial bolus and additional boluses, up to 2, administered as necessary. These same indications should be used when administering ‘shock bolus’ treatment to neonates with other conditions requiring fluid resuscitation, such as sepsis. In practice, fluid boluses are frequently used as maintenance of intravenous lines can be challenging, particularly if the foal remains in a stall with the mare.

Nursing Care: Nursing care is one of the most important aspects of treating recumbent foals. Foals should be kept warm and dry. They should be turned at two-hour intervals if they are recumbent. Feeding recumbent and minimally responsive foals can be a challenge if gastrointestinal function is abnormal and total parenteral nutrition may be needed. Recumbent foals must be examined frequently for decubital sore development, the appearance of corneal ulcers and for heat and swelling associated with joints and physis.

Umbilical Care

A chlorhexadine or dilute betadine solution is applied to the external stump twice daily for the first 3 days after birth. Recumbent foals are at increased risk of developing patent urachus or umbilical infection.

[...]