What's New in the NICU?
The neonatal intensive care unit, or NICU, is that special place in a veterinary clinic where premature, critical, and newborn foals receive intensive, round-the-clock care. The NICU handles everything from breathing problems to heart conditions to disease and more. If a foal's in trouble, it's the place to be.
Researchers from the U.K. (A. Borchers et al.) recently examined the survival and diagnoses of sick neonatal foals in a study published in abstract form in the Journal of Veterinary Emergency and Critical Care. They identified the primary diag-noses for foals entering the NICU.
Thirteen university and private equine referral hospitals enrolled 643 foals over the 2008 foaling season to be considered for the study. Researchers identified approximately 25% of these foals as having perinatal asphyxia syndrome, commonly known as dummy foal syndrome (possibly resulting from inadequate oxygen supply at or around the time of birth), 16% as having diarrhea, 16% as having sepsis (blood infection), and 8-10% as being premature. The outcomes for these diagnoses were generally quite good: 90% of dummy foal patients, 60% of septic foals, 50% of premature foals, and 90% of foals with diarrhea were discharged.
So what has the new millennium brought to the NICU that has helped veterinarians reach these numbers? The age of information technology, instant communications, and medical innovations have had an impact on this critical unit of equine medicine. Add to the mix a more optimistic attitude toward treating these foals, and a great deal is new in the NICU.
The Information Age
The 21st century has brought with it an amazing ability to collaborate and exchange information. The Internet and e-mail, in particular, have allowed us access to a world of information at our fingertips. Pamela Wilkins, DVM, MS, PhD, Dipl. ACVIM-LA, ACVECC, professor at the University of Illinois, has been involved in emergency care for many years. She says new technology allows her to easily connect with her colleagues in the American College of Veterinary Emergency and Critical Care (ACVECC).
This association is dedicated to advancing high standards of practice for those involved in veterinary emergency and critical care. It is also committed to promoting communication and dissemination of knowledge in relation to emergency and critical care medicine. The large animal group within the organization has been quite active, bringing many great minds together. Some of the new findings in neonatal care come from multisite collaboration between ACVECC members with similar areas of expertise.
In the spirit of promoting communications and knowledge, Wilkins called upon her network of ACVECC colleagues to answer the question, "What's new in the NICU?" Diplomates who responded included Fairfield Bain, MBA, DVM, Dipl. ACVIM, ACVP, ACVECC; Kevin Corley, BSc, BVMSm, PhD, MRCVS; Bettina Dunkel, DVM, PhD, Dipl. ACVIM, ACVECC, MRCVS; Eileen Hackett, DVM, MS, Dipl. ACVECC; Brett Tennant-Brown, BSc, BVSc, MS, Dipl. ACVIM, ACVECC; and Ben Buchanan, DVM, Dipl. ACVIM, ACVECC.
The No. 1 new NICU development these experts say they have observed is the increased intensity and targeting of the foal-monitoring process. According to Wilkins, veterinarians have seen "improved and more intense cardiovascular monitoring with the goal of instituting early goal-directed therapy (EGDT) to improve survival. This is paired with improved understanding of fluid therapy."
This EGDT particularly helps patients suffering from severe sepsis and septic shock. Sepsis occurs when bacteria overwhelm the bloodstream and the body goes into overdrive to fight them. The EGDT involves balancing oxygen delivery with oxygen demand by monitoring cardiac (heart) measures and blood circulation. The technique was introduced in human medicine in 2001 by Emmanuel Rivers, MD, and it has since been applied to equine medicine. Veterinary use of this intense monitoring process has significantly decreased NICU patients' mortality rates. Better understanding of fluid therapies and electrolyte balances also has helped veterinarians provide rapid response to sick foals.
Expanding on the increased diagnostics and monitoring, Wilkins and her ACVECC colleagues also cited the "development and use of potential prognostic indicators such as lactate and glucose concentrations and their changes over time in response to treatment" as emerging NICU advances. Basically, the ability to monitor things like lactic acids and sugar levels in blood can help veterinarians immediately respond to foals in crisis. The Borchers et al. study, for instance, revealed a significant association between the level of L-Lactate (LAC, the ionized form of lactic acid) in the blood and foal survival rates. Neonatal foals with higher lactate levels, which meant there was either a lack of oxygen flowing to tissues or the tissues weren't using the oxygen efficiently, had a much greater risk of dying than those with lower levels. According to this study, LAC is likely to become an important monitoring factor for treating foals in the NICU.
Other observations from the ACVECC on NICU developments, according to Wilkins, include an "increased emphasis on nutritional support including refined parenteral (intravenous) nutrition and early enteral (oral) feeding for enterocyte (intestinal lining cell) health." Essentially, veterinarians are customizing foal nutrition to ensure the cells in the intestinal tract that absorb nutrition and water are as healthy as they can be. Neonatal foals provided with the correct nutrients to benefit the development of these cells will likely experience more positive outcomes. (More information on nutritional support for sick neonatal foals...)
Wilkins also pointed out that researchers and veterinarians can now better recognize and define disease states such as ulcerative dermatitis, a probable colostrum-related skin disorder (similar to neonatal isoerythrolysis, or jaundice); neutropenia, a condition in the blood that shows an abnormally low number of neutrophils, which are the white blood cells needed to attack foreign bacteria in the bloodstream; and thrombocytopenia, where the patient has low blood platelet counts.
New information about all of these conditions has helped veterinarians develop improved treatment options. There also is a focus on "the potential importance of endocrine (hormonal) dysfunction in critically ill foals," according to Wilkins and her colleagues. In a study appearing in the Journal of Veterinary Internal Medicine in 2009, KA Hart et al. discovered that endocrine dysfunction occurs often in neonatal foals and that it negatively impacts both disease severity and survival rates. Certainly, more study of the endocrine system and of hormone imbalances is warranted based on these findings.
Medical and Technological Advances
On the medication front there has been a widespread discontinuation of dimethyl sulfoxide (DMSO) use for foals with prenatal asphyxia syndrome, according to Wilkins. Her colleagues noted that the introduction of vasopressin as a useful pressor agent in foals is another great NICU advance. Vasopressin is a hormone secreted by the pituitary gland that helps control water retention by reducing the urine output; it also increases blood pressure directly. These substances offer more tools for the veterinarian to help balance what is going on in the foal's body. Another new treatment, says Wilkins, is the "use of doxapram constant rate infusion and/or caffeine in supporting respiration in foals without a normal drive to breathe." Unimpeded breathing is critical to the successful outcome of many NICU cases.
With surgery, Wilkins said the ACVECC group has seen an "increased emphasis on future athleticism, including improved management of cuboidal bone immaturity and septic arthritis (infection of joints)." The cuboidal bones, located in the carpus (knee) and tarsus (hock), are a common area of immaturity in foals, and these abnormalities can be challenging to correct.
Wilkins said several of her colleagues mentioned that another change in the NICU is a "decreased number of interventions for treatment of umbilical problems including umbilical abscess and patent urachus (a leaking umbilicus)." These types of surgeries sought to correct infected areas of the umbilical stalk by removing (the area) surgically, but these problems are now being treated medically with good success. The move toward more intensive medical monitoring has likely decreased the need for some invasive interventions.
Jaye McCracken, DVM, of Hagyard Equine Medical Center in Lexington, Ky., agrees that monitoring in the NICU has become much more intense. She sees several technological advancements as being very beneficial to NICU operations.
"The ultrasound in general has become as important as a stethoscope," says McCracken. "The addition of color Doppler ultrasound, which shows blood flow, has been a great help." She offers the example of a sick foal with a kidney condition: A veterinarian used to place a catheter in the urinary tract and would have to observe blood in the catheter to diagnose a problem. Now conditions such as this can be diagnosed with ultrasound. Another example is using ultrasound to monitor the lungs of foals with suspected Rhodococcus equi pneumonia.
Another monitoring tool that has gained prominence in the NICU is the pulse oximeter. This device indirectly monitors the oxygen saturation in a patient's blood. "It was traditionally used in surgery," McCracken explains, "but now it's used on sickbed babies. Using this tool we can easily determine if a foal needs nasal oxygen in an immediate and responsive way."
MRI is an additional innovation that has a place in foal critical care. While it is not used often due to its high cost, in cases of potential spinal cord damage an MRI can help a veterinarian distinguish between growth plates and fractures, which is difficult and in some cases impossible to do using a traditional radiograph (X ray), especially in young animals.
Hyperbaric oxygen therapy (HBOT, in which the patient is exposed to concentrated, pressurized oxygen) is another addition to the NICU that might be useful for treating dummy foals and foals with septic physis, or infected growth plates. But McCracken notes that it is sometimes difficult to make objective findings with oxygen therapy. For dummy foals, success seems to be related to the severity of clinical signs. If the prognosis is fairly good the HBOT accelerates the healing process. But foals that are in serious medical trouble often cannot be helped. McCracken has had great success with the treatment of septic physis with oxygen therapy. Bain and others from the ACVECC also mentioned the use of hyberbaric oxygen in the treatment of septic arthritis and perinatal asphyxia syndrome as a development in NICU care. Studies are under way to determine whether HBOT is effective in controlled trials, corroborating field reports of the treatment's efficacy.
On the whole, McCracken has seen a decrease in the total number of foals admitted to Hagyard's NICU in recent years. She feels this is due to the struggling economy as well as the fact that field veterinarians can perform many more procedures, such as fluid therapy and antibiotic therapies, on the farm. Owners of foals admitted to the NICU tend to be better informed about foal care and are willing to spend the money to pursue positive outcomes. Even though some treatments can be performed in the field, the NICU is really the best place for a foal in crisis, due to the 24-hour monitoring and nursing care, as well as access to the best medical tools, she notes.
Finally, attitudes of both practitioners and owners seem to have changed in recent years, note our sources. Although the economy has made owners more cautious about expensive treatments, there seems to be a general shift away from the notion that sick foals are hopeless, says Wilkins. The information age, technological advances, and the increased success rates in foal treatment have made owners and veterinarians more likely to give a foal a fighting chance.
About the Author
Liza Holland is a freelance writer and voice talent based in Lexington, Ky.
POLL: University Equine Hospitals