A 15-year-old domestic short-haired cat was presented with a sudden onset of vomiting and disorientation. Initial contact from the owner was made over the telephone; this telephone conversation allowed the veterinary nurse (VN) to triage the patient, arrange an immediate appointment for veterinary examination and inform the veterinary team, ensuring the necessary equipment was prepared prior to the patient's arrival. The VN obtained a brief history, details of current patient condition and an estimated time of arrival. The VN provided the owner with advice on first aid treatment that could be administered prior to arrival at the practice. This patient was a known, unstable diabetic and therefore it was suspected that this patient was suffering from hypoglycaemia; it was advised that the owner administer a dextrose gel solution (GlucoGel, BBI Healthcare) or honey by rubbing it directly onto the cat's mucous membranes (MM) as recommended by Sparkes et al (2015).
Signalment
Species: Feline
Breed: DSH
Age: 15 years
Sex: Male (neutered)
Weight: 4.63 kg
BCS: 6/9
Triage assessment
On arrival to the practice the patient was again triaged and seen immediately by the veterinary surgeon (VS). A primary survey was carried out to determine any life-threatening conditions as described by Brown and Drobatz (2018). The four major body systems were evaluated this included:
- Respiratory — rate, effort and rhythm
- Cardiovascular system — MM colour, capillary refill time, pulse rate, quality and rhythm
- Neurological — mentation and ability to ambulate
- Renal — palpation of bladder and ability to urinate.
The primary survey revealed the patient had significant changes in demeanour (obtundation), reduced ability to ambulate (ataxia), tachycardia (>200 beats per minute (bpm)) and a moderately sized, flaccid bladder. This was suspected to be due to hypoglycaemia therefore the patient's blood glucose (BG) was immediately checked; a capillary blood sample was obtained from the patient's left pinna and tested using a glucometer. This revealed a BG of 3.5 mmol/litre (post glucose administration by the owner, 20 minutes previous) (normal range: 3.3–6.7 mmol/litre).
Following initial examination and stabilisation, a secondary survey was carried out; this included a full physical examination, further diagnostics and obtaining a thorough history from the owner. The clinical history revealed that the patient had previously been diagnosed with diabetes mellitus and was receiving insulin therapy but was currently unstable. To establish the cause of hypoglycaemia the following questions were asked:
- Any changes to normal routine?
- Any changes to the dose, frequency or timing of insulin?
- Are the correct insulin syringes being used?
- Is the insulin in date, being stored and prepared correctly?
- Are there any changes to appetite or diet? Additional treats? Vomiting?
- Are there any changes to normal exercise/activity level?
- Is your pet receiving any other medications?
This detailed history revealed that the patient's insulin dose had been increased from 1 to 3 IU of Prozinc (Boehringer Ingelheim Vetmedica) following a high fructosamine result 5 days previous. Therefore, an overdose of insulin (due to increased dose) was the likely cause for hypoglycaemia.
Initial interventions
The patient's BG level was 3.5 mmol/litre; Schoeman (2012) states that hypoglycaemia is a BG of <3.5 mmol/litre, however this reading was post oral glucose administration therefore it was likely to have been <3.5 mmol/litre prior to arrival at the practice.
Following admission, a venous blood sample was obtained from the jugular vein for an emergency database which included a complete blood count, serum biochemistry and electrolytes. The emergency database found a mild hyperproteinaemia (82.0 g/litre) (normal range 60–79 g/litre) and hypoglycaemia (3.0 mmol/litre), the rest of the blood work was unremarkable. The emergency database was used to assess the glucose requirement, concurrent diseases that may affect glucose levels such as hepatic disease, and to highlight any other abnormalities that may need addressing such as dehydration.
A urine sample was obtained via a free catch sample and tested for dipstick, specific gravity and sediment analysis. The results showed no evidence of glucose in the urine, which in an unstable diabetic patient could suggest hypoglycaemia, the rest of the urine results were unremarkable.
Following the initial BG reading of 3.5 mmol/litre an intravenous (IV) catheter was placed and a bolus (0.25 g/kg, diluted at a ratio of 1:3 in 0.9% sodium chloride) of IV dextrose was administered. The patient's BG level was monitored via ear pricks every 30 minutes until the BG returned to normal.
Pathophysiology of diabetic hypoglycaemia
Diabetic hypoglycaemia in this case was due to an iatrogenic overdose of insulin. Patients with diabetes mellitus have a reduced ability to regulate their own BG levels either through resistance to insulin or a lack of insulin production. This patient had been diagnosed with diabetes mellitus and was therefore receiving synthetic insulin (Prozinc, Boehringer Ingelheim Vetmedica) therapy. Insulin facilitates and regulates the uptake of glucose into cells, therefore excessive insulin levels can result in increased uptake of glucose, causing a low BG.
Discussion of veterinary nursing implications
Hypoglycaemia presents a genuine life-threatening emergency in the intensive care unit (ICU) (Chapman, 2013; Humm and Kellett-Gregory, 2016). VNs play a vital role in the emergency and critical care of hypoglycaemic patients. This patient care report will discuss and evaluate the nursing care involved with maintenance of intravenous catheter, monitoring of blood glucose and dietary management.
Maintenance of intravenous catheter
Following admission IV access was immediately gained. A 24G IV catheter was placed in the right cephalic vein. The catheter site was aseptically prepared by clipping the hair on the right fore leg, over the cephalic vein. The skin was prepared using dilute chlorhexidine and surgical spirit as supported by Dorey-Phillips and Murison (2008) who found this method to provide better sterility than surgical spirit alone. An over-the-needle catheter was selected as they have minimal complications, are cheap, easy to place and are well tolerated (Adamantos and Alwood, 2007). The catheter was placed using an aseptic technique. This was then bandaged in place to stabilise the catheter and to prevent contamination and patient interference (Goddard, 2010). Goddard (2010) states that using a good aseptic technique to place IV catheters can help to reduce associated complications such as infection, therefore this is paramount to success.
Haskey (2016) and Roberts (2013) recommend the placement of a central venous line for all critically ill patients as it allows: administration of multiple drugs concurrently; central venous pressure monitoring; and blood sampling. Central venous catheters can also be left in situ for longer than peripheral catheters, decreasing the need for catheter changes and the associated pain and stress this causes to the patient. In this case a peripheral venous line was selected over a central venous line as it allowed easy and rapid IV access, staff were experienced in their placement and management, they are ideal for short-term placement (Adamantos and Alwood, 2007), and they facilitate administration of intravenous fluid therapy (IVFT) and IV medication, and are generally well tolerated by patients (Haskey, 2016).
VNs play a vital role in the maintenance of IV catheters. Davis et al (2013) recommends unbandaging the catheter site daily to check patency, and for signs of catheter displacement, phlebitis, thrombophlebitis, infection, constriction of blood flow, catheter-associated pain or discomfort, and patient interference. In the author's practice this is carried out twice daily. If the IV catheter is not being used to deliver IVFT, it is recommended that the patency is checked every 4 hours (Davis et al, 2013). Research has found that flushing an IV catheter with saline is as effective as using heparin solutions (Davis et al, 2013; Ueda et al, 2013). Clear nursing instructions (NI) must be left on the hospitalisation chart to ensure IV catheters are flushed, patency is maintained, and the IV catheter site is monitored. If at any point the bandage becomes soiled, wet or loosened the catheter should be checked and the bandage replaced (Davis et al, 2013). If there is a risk of contamination the IV catheter must be removed immediately.
Patients must be monitored closely to ensure they do not interfere with the IV catheter as this can cause catheter displacement and contamination. To prevent patient interference an Elizabethan collar can be used, although in this case the patient was not interfering with the IV catheter and using an Elizabethan collar could have potentially caused further disorientation, so a collar was not used.
Blood glucose monitoring
Blood glucose monitoring is an essential part of the emergency care for patients presenting with hypoglycaemia. BG monitoring allows the veterinary team to assess the response to initial treatment and requirements for further treatment. VNs must be able to promptly obtain and run blood samples, reporting any parameters that require rapid intervention (Chapman, 2013).
Prior to arrival the owner administered first aid treatment, this included administering a dextrose gel solution (GlucoGel, BBI Healthcare) and offering a bowl of food. As part of the initial examination the BG level was taken using a glucometer. BG samples are routinely taken from capillaries in the pinna, carpal pad or footpad. Zeugswetter et al (2010) state that the pinna is the only validated sampling site, however, metacarpal pads or footpads make an excellent alternative sampling site. On this occasion the sample was obtained from the patient's left pinna. Prior to sample collection the ear was massaged to increase blood flow. A lancet was used to prick the ear and allow a drop of blood to be collected. Care must be taken not to squeeze the sample site to increase sample size as this can potentially express tissue fluid, which can have a significantly higher BG than capillary blood (Cengiz and Tamborlane, 2009). At this stage the patient's BG level was 3.5 mmol/litre.
An initial bolus of IV dextrose was administered. The patient's BG was then monitored every 30 minutes until BG level returned to normal; following this the BG was checked every 2 hours. To create a BG curve, BG is usually measured every 2 hours for a minimum of 12 hours (Ristic, 2011; Scudder et al, 2016). The process for sample collection described above was followed. The sample site was alternated between the left and right pinna to avoid excessive trauma. Phillips (2018) discussed the challenges faced with frequent blood sampling, and reported that frequent ear pricks can be uncomfortable and cause stress to the patient. With this in mind it is important to consider the patient's welfare, although not used in this case many authors advocate the use of a topical local anaesthetic cream (EMLA, AstraZeneca) to minimise the pain and trauma associated with frequent ear pricks (Gamble, 2015; Van Oostrom and Knowles, 2018). Topical local anaesthetic creams such as EMLA have been used successfully in both the human and veterinary environment (Fetzer, 2002; Rogers and Ostrow, 2004; Paskeviciute, 2017; Van Oostrom and Knowles, 2018) to desensitise the skin prior to venepuncture, however there is some variation in the recommended time of application prior to venepuncture. In a 2018 study Van Oostrom and Knowles concluded that EMLA cream needed to be applied 60 minutes prior to venepuncture, therefore successful use required adequate planning and time.
A BG curve was plotted to allow easy assessment of BG. Monitoring of BG allowed the VS to make appropriate adjustments to the dose of insulin given and time of administration (Clarke and Silverstein, 2010).
The author's practice routinely use an AlphaTrak 2 glucometer (Zoetis) for BG measurements, which are specifically calibrated for cat and dog BG, and are therefore more reliable than those calibrated for human BG levels (Zoetis, 2017). Pet glucometers are portable and provide rapid, accurate BG measurement using a small volume of blood (Le et al, 2013). This method is thought to be less invasive than repeated venous samples. However, there can be a slight variation in BG between venous and capillary samples (Cengiz and Tamborlane, 2009).
The degree of hypoglycaemia was later confirmed on the emergency database with the serum biochemistry revealing a BG level of 3.0 mmol/litre. The difference between the results may be due to either the sensitivity of the glucometer or variation between venous and capillary BG concentrations. Several studies have confirmed that glucometers are not as accurate as laboratory machines, but they are still considered a good choice for rapid, cost-effective sampling (Le et al, 2013).
An alternative method of measuring BG levels would be continuous BG monitoring. This method involves the placement of a subcutaneous catheter-like monitor which allows measurements of interstitial BG every 5 minutes for up to 6 days (Scudder et al, 2016). This method offers an easy way to take repeated BG measurements, without causing stress to the patient (Wiedmeyer and DeClue, 2008). However, continuous BG monitors take time to fit and require repeated calibration (Scudder et al, 2016), therefore if the patient does not already have a continuous BG monitor fitted then it would be of limited benefit during the stabilisation of the hypoglycaemic patient. Care must be taken to reduce the stress to cats when measuring BG as stress can increase BG levels, which can be misinterpreted (Wiedmeyer and DeClue, 2008). Schermerhorn (2010) suggested the placement of a central venous catheter to facilitate repeat venous blood samples with minimal stress caused to the patient, however in this case a peripheral venous line was placed but used for administration of IVFT. The VS had estimated that this patient was 5% dehydrated therefore IVFT (Hartmanns) was used to correct dehydration. This patient was started on three times maintenance (150 ml/kg/24 hour) for 12 hours then reduced to maintenance (50 ml/kg/24 hour) until hydration was corrected. To preserve patency of the IV catheter, it was elected not to use the IV catheter for blood sampling.
The patient responded well to the initial treatment and an improvement in BG was seen within 30 minutes. Once the patient's demeanour improved and he could safely swallow, food was offered. Feeding a palatable meal is an effective way to ensure consumption (Huang, 2012) and effectively increase BG levels.
Dietary management
Dietary management is another very important aspect of nursing patients with hypoglycaemia. Feeding the patient is an effective method of rapidly increasing BG levels.
Patients with diabetes are usually fed a high protein and low carbohydrate diet (Rand and Marshall, 2005; Rucinsky et al, 2010; Stuttard, 2014). High protein diets will aid glycaemic control, reducing postprandial hyperglycaemia (Rand and Marshall, 2005), however in the emergency situation a high carbohydrate diet is preferable to rapidly increase BG.
Stuttard (2014) states that it is important to be consistent with dietary management and advises using the patient's normal feeding regimen while the patient is hospitalised. A patient assessment questionnaire (PAQ) allows the veterinary team to gain necessary information form the owner regarding normal routines (Main, 2011). Voluntary food intake is essential for increasing BG levels and therefore having an idea of patient preferences can be invaluable. In an emergency situation it is not always appropriate to complete a PAQ as providing patient care takes priority and often owners are distressed. By not completing a PAQ the veterinary team will not be able to replicate normal routines during the initial period of hospitalisation. Fortunately, due to a complex history the veterinary team were already aware of this patient's normal feeding regimen as it was a vital aspect of his diabetic management. This patient's normal feeding regimen consisted of a commercial high protein, low carbohydrate diet (Royal Canin, Diabetic). The patient was fed small amounts of food throughout the day.
Care should be taken to ensure the patient's demeanour and ability to swallow has improved prior to offering food. This patient had already consumed a bowl of chicken prior to arrival at the practice, however he was still hypoglycaemic on arrival. It is very important to increase BG levels as soon as possible, therefore Stuttard (2014) and Rand and Marshall (2005) recommend feeding a highly palatable diet to ensure consumption. In this case the patient was initially offered his normal diet which he did not voluntarily eat. Hand feeding was attempted but was unsuccessful. Due to the risk of increased patient stress, food aversion and aspiration pneumonia syringe feeding was not attempted (Kathrani, 2016). Warming food increases aroma and therefore enhances palatability (Michel, 2001), following this recommendation the patient was offered some warm white fish which provided successful voluntary intake.
The patient was offered small amounts of warmed white fish every 2 hours, the BG levels were monitored. NI were clearly documented on the hospitalisation chart which included type of food, quantity of food and frequency of meals. They allowed clear and concise communication between the veterinary team regarding patient care. Food intake and BG levels were also clearly documented on the hospitalisation chart. This feeding regimen was suitable for increasing BG in the hypoglycaemic patient, but ideally the patient would require a consistent feeding regimen and insulin therapy to stabilise BG long-term.
Conclusion
VNs play a vital role in providing a high quality of care to critically ill patients in the ICU (Smith and Witchell, 2016). Hypoglycaemia provides a genuine emergency (Chapman, 2013; Humm and Kellett-Gregory, 2016) and requires prompt delivery of veterinary care and patient monitoring. The primary goal is to rapidly increase BG levels, which requires the VN to accurately monitor the patient's BG levels and promptly report any abnormalities that require immediate intervention (Chapman, 2013). There are various methods available for measuring BG with a slight variation in results, however, the use of a glucometer and capillary blood sampling was an easy and efficient way to monitor BG levels in this patient. Home BG monitoring should be encouraged to allow rapid detection of developing abnormalities (Scudder et al, 2016), and therefore prompt veterinary intervention.
As highlighted in this patient care report, simple welfare is often overlooked. To minimise pain, stress and trauma associated with frequent ear pricks for BG readings, the use of EMLA cream should be considered to enhance the overall welfare of the patient (Paskeviciute, 2017; Van Oostrom and Knowles, 2018).
Communication is a huge part of the successful running and delivery of care in the ICU. Communication begins with initial contact from the owner, at this point it is essential the veterinary team efficiently triage the patient and provide necessary first aid advice. The author feels that there is a need for further training in the triage of emergencies and basic first aid, especially for reception staff who have usually had little or no training.
Communication regarding patient care is extremely important. Clear and concise NI must be documented on the hospitalisation forms to detail the specific nursing care required, allowing the successful implementation of nursing care (Smith and Witchell, 2016).
VNs also play a vital role in the education of owners (Scudder et al, 2016), especially in diabetes management. In this case good client education allowed the owner to correctly detect the clinical signs of hypoglycaemia, promptly contact the veterinary practice and provide rapid first aid care. This prompt action and delivery of first aid treatment prevented any lasting damage, and overall improved patient outcome. It is very important that all owners of diabetic patients have a fast-acting carbohydrate solution such as GlucoGel or honey readily available.
KEY POINTS
- Hypoglycaemia is defined as a blood glucose of <3.5 mmol/litre.
- Hypoglycaemia provides a genuine life-threatening emergency.
- Veterinary nurses (VNs) play a vital role in providing a high quality of care to critically ill patients.
- Blood glucose monitoring allows assessment of current treatment and the need for further treatment.
- VNs must be able to obtain rapid blood samples and report any parameters that require intervention.
- Patient welfare should be considered when monitoring blood glucose.
- Dietary management is an important aspect of nursing hypoglycaemic patients.
- VNs also play a vital role in the education of owners for diabetes management.
- Communication is a huge part of the successful running and delivery of care.