Emergency and Critical Care for Adult Horses
Intensive Care Unit | Monitoring Equipment | Support for Heart & Circulation | Intravenous Fluids | Blood Pressure | Electrocardiograms | Blood Gas Analysis and Haematology | Nutrition | Blood Transfusions
Introduction
Adult horses may require intensive care for multiple reasons: one of the most common conditions is colic. In particular horses that have undergone colic surgery need intensive monitoring and 24h care and supervision to allow for a speedy and complete recovery and provide the best possible outcome. Other diseases which require a high level of medical attention and close supervision include diarrhoea (Colitis), diseases associated with significant amounts of bleeding (Blood transfusions), neurological disorders and some respiratory conditions (Respiratory distress).
The Intensive Care Unit (ICU)
Our intensive care unit consists of six dedicated stalls and an associated nursing area allowing us to deliver the best possible care and supervision to our patients. The ICU is temperature controlled to minimise the negative effects of varying temperatures on the patients. Each stall is equipped with facilities that allow delivery of continuous intravenous infusions (”drips”) of electrolyte solutions and colloids. Large volumes are provided via gravity flow while small volumes or medications that require precise amounts to be administered are given via a “fluid pump”, a device that can, accurately to very small volumes, deliver an exact amount of medication over a certain amount of time. A central nursing area is stocked with all commonly used medications and equipment. All equipment that may be used in an emergency situation, such as a blocked airway, sudden cardiac arrhythmia or cardiac arrest or a generalised seizure is localised in one portable cart (“crash box”) so that everything needed is on hand immediately should such a situation arise. All personnel are trained in reacting to and handling of emergency situations.
Our ICU is connected to an oxygen generator which allows generation of air containing up to 90% of oxygen and can provide a wide spectrum of oxygen flow rates to allow delivery and tailoring of oxygen flow to patients in need of supplemental oxygen (for example horses with Respiratory distress or Blood loss).
The ICU also contains a special stall designed for patients with neurological disorders. The walls of this stall are padded soft rubber material to prevent injury and a hoist is located on the ceiling which allows us to support a recumbent or weak horse in a sling (Anderson sling) and transport it safely in and out of the stall. The stall is located closest to our diagnostic imaging facilities to guarantee easy access to all imaging modalities that may be needed.
Monitoring Equipment
Monitoring stations including blood pressure measurements, blood glucose (blood sugar) measurements, electrocardiogram (ECG) recording, blood gas analysis (measurement of oxygen, carbon dioxide, electrolytes and lactate in the blood to assess lung function and perfusion to peripheral organ systems), plasma oncotic pressure measurement and haematology (determination of white and red blood cell count in the patient’s blood) are positioned close by to enable 24h evaluation of the patients’ well being. We also have the ability to perform out-of-hours cell counts and cytological evaluations of other fluid samples, for example joint fluid aspirates or peritoneal fluid (fluid that surrounds the bowel) samples which is an important tool when determining whether or not a joint may be infected or whether a horse may need to undergo colic surgery.
Support for the heart and circulation
Compromised patients often suffer from disturbances of their normal vital functions. A normal horse can maintain blood delivery to all organs naturally and well working lungs ensure adequate supply of oxygen to all body parts. Delivery of oxygen relies on an adequate blood volume which transports the oxygen to all organ systems.
Some equine conditions, such as colic and colitis, are associated with severe electrolyte and fluid losses and require administration of large amounts of intravenous fluids and electrolytes to ensure that all organ functions are preserved. Using blood gas analysis, we have the ability to determine which electrolytes need to be supplemented for the individual patient and how much fluids we exactly need to deliver. Horses with large amounts of nasogastric reflux due to colic may require 100L of intravenous fluids or more per day. If this vital support is not delivered or instituted too late, an initially mild disease can rapidly progress into a life-threatening complication and permanent organ damage or even death can occur.
Intravenous Fluids
Our ICU is outfitted with all equipment needed to care for compromised horses. Large volumes of continuous intravenous fluids are provided via gravity flow using specifically designed suspension systems while certain medications are administered by high-precision fluid pumps that allow accurate delivery of very small volumes to the patients.
Horses with loss of blood protein into the gut or urine may need to be supported with so called colloids (fluids that contain large protein-like particles). Blood proteins normally retain fluid in the blood vessels and prevent leakage of fluid out of the vessels which would lead to oedema formation (accumulation of fluid in the tissues). If blood protein is low, colloids can help to keep the intravenous fluids in the blood vessels. Measurement of plasma oncotic pressure aids in determining whether a patient is in need for colloid support and enables us to determine whether oedema formation is likely.
Blood Pressure
As the condition of critically ill patients can change rapidly, meticulous attention is paid to monitoring of the patient. Blood pressure is measured similar to the method used in humans only that the cuff is placed around the base of the tail rather than the forearm. Frequent measurements in critically ill or unstable patients ensure that any worsening of the condition is detected early and immediately treated appropriately.
Electrocardiogram (ECG)
We also have the ability to monitor the heart rhythm continuously or intermittently, as required, by connecting the horse to an ECG. The horse is equipped with a so called telemetry unit which transmits signals to a distant laptop where heart rate and rhythm can be monitored and recorded continuously. In healthy horses, we can monitor the heart rhythm during rest and at exercise as seen in the picture, however, in ill patients we usually only monitor the heart rate at rest while the horse is standing in a stable. In mares that experience problems during their pregnancies (high-risk pregnancies) this equipment is used to monitor the heart rate of the foetus which can be obtained by placing the electrodes that transmit the heart beat around the abdomen.
Blood gas analysis and Haematology
Oxygen and carbon dioxide levels in the arterial blood provide an indication of lung function. Lactate levels can also be determined using a blood gas machine: lactate increases in the blood when peripheral organs, such as muscles, are not supplied with enough oxygen. This may occur in patients with respiratory distress or in dehydrated horses for example due to colitis or colic. Electrolyte levels in the blood can also be determined.
The white blood cells play an important part in the body’s ability to fight infections and monitoring of white blood cell numbers in the blood constitutes an important assessment tool for the patient’s condition. We can determine white blood cell counts in the blood and other haematologically values around the clock as necessary and also have the ability to evaluate the morphology (appearance) of all cell types if necessary.
Nutrition
Nutrition is very important for the recovery of all critically ill patients. Without adequate nutritional support, critically ill patients lose body weight quickly and become debilitated. In some breeds, particularly ponies, donkeys and miniature breeds, decreased food intake can lead to a life-threatening complication called hyperlipaemia (excess fat in the blood) which is caused by rapid break down of fat reserves during periods of stress, disease and starvation.
In our ICU we employ several methods to ensure that each patient is provided with exactly what is needed. A nutritional plan is incorporated into the treatment plan of each horse that enters the hospital. This plan may be as simple as providing the feed the horse is fed at home or, at the other end of the spectrum, may entail total parenteral nutrition (nutrition infused into the blood stream). Each patient is weighed on admission, providing the disease process does not prohibit weighing, and at regular intervals throughout and at the end of hospitalisation to ensure that the nutritional plan meets each individual horse’s needs.
Horses with normal appetite and intestinal function
We offer a wide variety of different horse feeds for horses with a normal appetite and intestinal function. A member of our technician team will take a detailed nutritional history from you when your horse is admitted to the hospital and we will try to mimic your horse’s normal feeding schedule as closely as possible. We are also happy to order certain feeds in for your horse should it be necessary.
Horses that are inappetent or unable to swallow but have normal intestinal function
Some horses lose their appetite due to their primary disease process and will not take in any feed voluntarily. For these horses, we offer a buffet-style variety of different feeds including hard feed, a variety of forages, fresh grass and treats in an attempt to coax them into eating.
Should all attempts fail and a patient is at danger of starvation, we may opt to institute enteral nutritional support as described below. Horses that are unable to pick up, chew or swallow feed (for example due to neurological disorders, choke, Strangles, or pharyngeal obstruction) but have normal intestinal function are provided with enteral (via the intestine) nutritional support. This involves administering slurries or liquid feed material via a nasogastric tube directly into the stomach. This may be done by passing a tube several times daily or by leaving a soft, pliable small diameter tube in the oesophagus (food pipe).
Horses with abnormal intestinal function
Horses with abnormal intestinal function may not be able to take in or digest any feed via the normal route (for example horses with nasogastric reflux due to colic). These patients require parenteral nutrition which entails administration of glucose, protein and lipid directly into the blood stream, thereby bypassing the intestine. Parenteral nutrition is made up in our pharmacy specifically for each patient under sterile conditions and is delivered via special fluid pumps that allow exact control of the amount delivered. Patients receiving parenteral nutrition need to be monitored very carefully to ensure that electrolytes remain within normal limits and blood glucose levels are tightly controlled. Some patients may even require insulin (the drug used by diabetic human patients to control blood glucose) to correct blood glucose levels.
Blood transfusions
A dedicated herd of 5 blood donors, Darcy, Bruce, Finnigan, Lollipop, and Paddy are available should your horse require an emergency blood transfusion. The blood donors live in a field close by so that blood can be collected and administered within a very short period of time should it be required. A blood transfusion may be required if your horse has lost large quantities of blood either due to trauma, for example rupture of a major vessel, during surgery or due to internal bleeding (see case haemoabdomen). Horses, just as humans, have different blood groups and our donors include several different common blood groups as well as one universal donor (Paddy). Our blood donors are all very large horses and don’t mind donating 8-9L of blood for patients in need.
Usually, a cross match (looking for compatibility between blood donor and recipient) is not necessary if your horse never had a blood transfusion before; however, it may become necessary should your horse require multiple transfusions. Our blood donors also provide fresh plasma and platelet transfusions for our patients should your horse require either of these.
Above: Blood donor horses at the RVC ERH