Diabetic ketoacidosis (DKA) is a serious, life-threatening metabolic complication of diabetes mellitus, which, whilst most common in type 1 diabetes mellitus, can on rare occasions present in patients with type 2 diabetes mellitus.1,2
DKA develops in those patients with either an absolute deficiency of insulin or a relative lack of insulin brought about by an excess of counter regulatory hormones.
Prevalence of DKA
Despite improved treatment strategies, DKA has an estimated death rate of 28 per 100, 000 patients with diabetes in the UK.3 Unfortunately there does not appear to be any reported statistics for deaths due to DKA within Ireland.
In view of the nature of this condition most deaths occur in those aged under 45 years with some authors proposing DKA, as the most common cause of death in all diabetics under the age of 20 years.4
Given these statistics, it is imperative that nurses who are presented with this condition act promptly to ensure treatment is instigated immediately to guarantee best possible outcome for the patient.
One of the most important aspects of care of the patient with DKA is isolation of trigger factors associated with the condition.
Research has repeatedly demonstrated infection as the most common precipitating factor in DKA,5,6 with factors such as missed insulin dose, new onset of diabetes and drugs and alcohol also identified.7
Whilst it must be acknowledged that it is not always possible to identify a cause for DKA, a full investigation is warranted if further episodes are to be avoided.
|DKA diagnosis and symptoms
Diagnosis of DKA z Blood Glucose >12 mmol/l9
Presentation and diagnosis
Patients suffering from DKA may present with varying symptoms depending upon the severity of the condition. The classic patient presentation offers a clinical history of hyperglycaemia, polydipsia, polyuria, fatigue and weakness.
Other complaints may include abdominal pain and vomiting which are believed to be a result of ketoacidosis and gastric stasis.8
Whilst there appears to be disparity between professionals as to what constitutes actual diagnosis of DKA, Table 1 offers a rough guide, which may be of benefit.
Therapeutic goals appear to remain consistent within recent research literature for treatment of DKA. Replacing of fluid loss, decreasing serum blood glucose, reversing acidosis and ketosis, correcting electrolyte imbalances and identifying underlying causes are the main priorities of care.10,11
Initial treatment should assess the patients airway, with intubation and ventilation a possible requirement for those severely comatosed.
A nasogastric tube may be required if the patient is vomiting to prevent aspiration.
The next priority should be fluid replacement. Hypotension requires rapid fluid resuscitation with 0.9% saline solution being the fluid of choice.12 It is vital that a patient receives fluid and not insulin as first priority.
Fluid replacement alone reduces hyperglycaemia and acidosis and increases tissue perfusion whilst being necessary to correct the electrolyte imbalance that has occurred.
Studies have demonstrated that a high volume of fluid replacement in a short time initially will have a positive effect on treatment outcomes, though care must be taken to ensure adequate assessment of the patient for such treatment.13 It is vital that an accurate fluid balance chart is maintained at all times during care of the patient with DKA.
Once fluid replacement has been initiated an insulin infusion should be commenced. A continuous infusion of insulin that yields a ratio of 1:1 (ie. 50 units of rapid acting insulin to 50ml of 0.9% saline solution) has been accepted as method of choice.14
Continuous infusion negates the difficulty of erratic absorption which can result in volume depleted patients. A continuous low dose of insulin (ie. six units) has also been shown to be as effective as high or fluctuating insulin administration, thus an infusion set at a rate of six units an hour is considered gold standard.
It is vital that the nurse ensures an accurate record of blood glucose readings in case the infusion needs to be increased or decreased at any stage.
Once blood glucose has fallen to below 10mmol/l the infusion should be halved and 0.9% saline solution exchanged for dextrose saline as the patient now requires carbohydrate.10
The above recommendations may need to be adjusted with individual patients and nurses should observe the patient continuously for signs of hypoglycaemia.
Potassium replacement should only commence after a laboratory result has been established. It should be noted that the initial potassium result might be high offering a false reflection of the patients true condition. Indeed it has been suggested that hypokalaemia may be masked by the presence of acidosis itself.7 A low laboratory result indicates that potassium replacement should commence immediately as further hypokalaemia is likely with rehydration.
Additional potassium replacement should be based upon further laboratory analysis with two hourly urea and electrolyte samples recommended until the patient is haemodynamically stable.10
Use of bicarbonate
There has been much discussion about the use of bicarbonate in the treatment of DKA with significant disparity in opinion. The most recent studies suggest that bicarbonate therapy is unnecessary when the blood pH is above 7.1.15 Thus bicarbonate should only be considered for use in treatment of DKA when blood pH is less than 7.0.
Given the nature of DKA it is imperative that each patients knowledge of diabetes and the complications of diabetes be revisited by both the patient and a healthcare professional.
In light of the inherent dangers associated with DKA, all patients with diabetes must be educated to recognise both signs and symptoms in order that prompt action may be taken.
With the introduction of modern technology it is now possible for patients to record blood ketones ([beta]-hydroxybutyrate), hence much earlier detection of impending DKA is possible. Involvement of the diabetes nurse specialist at the early stages of admission is also vital to ensure follow up care and support is provided.
DKA must be recognised and treated as the life threatening condition that it is. Staff should be regularly updated on treatment changes and patient presentation so that no patient is misdiagnosed. Treatment should commence immediately with fluid replacement taking precedence over insulin administration.
Patient education, reason for DKA development and prevention of further episodes are all areas which must be addressed by healthcare professionals involved in the care of the patient. Where possible all patients should be referred to the diabetes nurse specialist for education and follow up care.
David Chaney is a lecturer in the School of Nursing and Midwifery studies, Trinity College Dublin
References available from the INO Library