Why too many red cells are a problem: Nursing the polycythemia patient
We know what happens when our patients don’t have enough red blood cells. But what happens if they have too many?
This can be just as dangerous for our patients - so it’s vital that we spot the signs of polycythemia quickly, and understand how to treat and nurse these patients.
That’s why, in this post, I’m going to tell you exactly what polycythemia is, why it occurs, what signs we see, and how we treat the condition… As well as how to provide great nursing care to your polycythemia patients.
Want to know more about caring for haematology patients? I’m running a special event in July which will show you how, and give you the skills to do more with these patients. To be the first to know more about this, sign up for the mailing list!
What Is Polycythemia?
Polycythemia, or erythrocytosis, is where excessive red cells are present in the blood. Technically, erythrocytosis is the term for excessive RBCs, and polycythemia can include increases in other blood cells. But the two terms are often used interchangeably, and I’m going to do the same in this post.
Polycythemia can either be relative or absolute.
Relative Polycythemia
Relative polycythemia is where there is not an increase in RBC number, but because the plasma volume is lower, the PCV appears higher. This is seen due to changes in fluid balance, rather than changes with the RBCs themselves.
We can also see transient polycythemia (with no clinical signs) in patients after intensive exercise - as the spleen contracts and releases RBCs, to deliver more oxygen during exercise.
Absolute Polycythemia
Absolute polycythemia is where red cell numbers increase due to an increase in RBC mass. It can be a primary or secondary condition:
Primary Polycythemia (Polycythemia Vera)
Primary polycythemia is also known as polycythemia vera. It is a neoplastic disease of the bone marrow (myeloproliferative disease) resulting in high numbers of RBCs being released from the bone marrow into the bloodstream.
Secondary Polycythemia
Secondary polycythemia is all about erythropoietin (EPO). We’ve chatted a lot about EPO before, in our endocrine and renal posts. It’s a hormone released by the kidney in response to low blood oxygen concentrations. The EPO then stimulates the bone marrow to release new RBCs.
In secondary polycythemia, EPO levels are high. This means the patient has an underlying disease causing chronic hypoxia - such as a chronic respiratory or cardiac disease. Or it means that they have an EPO-secreting tumour.
What Signs Do We See?
Common clinical signs of secondary polycythemia include:
Bright red mucous membranes
Polyuria
Polydipsia
Bleeding
Seizures
Ataxia
Behavioural changes
Weakness
Blindness
Why do we see these? Well, when there are too many RBCs in the blood, it becomes ‘sludgy’ (yes, that IS a technical term!) and can’t flow properly.
Poor flow = poor perfusion = poor delivery of oxygen to our cells and tissues.
Given that the brain needs a LOT of oxygen, glucose, and all the other good stuff that blood provides… When the blood can’t flow there, we quickly see neurological signs.
Patients are often PU/PD as they try to increase their fluid intake and ‘dilute’ their blood. But, as it isn’t relative polycythemia, this won’t work - as the body releases more and more RBCs.
Because of the neurological signs and poor perfusion we see in these patients, they need quick triage and stabilisation. Like our anaemic patients, this is where we come in as nurses!
How Is It Diagnosed?
We diagnose polycythemia based on haematology, where we see an increased RBC, PCV, haematocrit and haemoglobin level.
But this doesn’t tell us whether our patient has relative or absolute polycythemia - only that the red cells are high.
So, to work out if you have a relative or absolute polycythemia, you need to look at your patient. Are there any signs of dehydration? Does it look like they need fluid therapy? If so, chances are you’ve got relative polycythemia.
Absolute Polycythemia
Absolute polycythemia is then diagnosed as either primary or secondary by measuring erythropoietin levels. In a patient with primary polycythemia, EPO levels will be low, or low-normal.
Patients with secondary polycythemia have high EPO levels. We also need to investigate the reason for this, as their condition is secondary to an underlying disease. Common tests performed include:
Thoracic auscultation
SPO2 measurement
Arterial blood gas measurement
Chest X-Rays
Echocardiography
ECG
What About Treatment?
Our treatment methods depend on the type of polycythemia the patient has.
Relative Polycythemia
Relative polycythemia is treated with intravenous fluid therapy - as we correct the hydration deficits we see in these patients and restore a normal circulating volume.
Primary Polycythemia
Primary polycythemia is treated with regular phlebotomy. We remove around 10-20ml/kg of blood (similar to a blood donation!) and replace it with crystalloids, aiming for a PCV of around 50%.
This is repeated as needed to manage the patient’s clinical signs. We may also administer hydroxyurea, a medication used to treat sickle cell anaemia in humans. This drug causes bone marrow suppression, reducing the number of RBCs released.
Secondary Polycythemia
To treat secondary polycythemia we need to manage the underlying cause. This includes treating any underlying cardiac or respiratory disease and removing any EPO-secreting tumour present.
If the disease cannot be effectively managed - e.g. if it’s end-stage, careful phlebotomy can be performed. However, as the patient needs higher RBC levels due to their hypoxia, we should leave their PCV slightly higher than normal. The goal is to remove just enough blood to eliminate the patient’s clinical signs.
How To Nurse The Polycythemia Patient
There is a lot to think about when nursing patients with polycythemia. Our main considerations include:
Fluid therapy
Phlebotomy
Nutrition
Oxygenation
Monitoring
General nursing care
Fluid Therapy
Patients with polycythemia require IVFT to dilute their blood and replace any fluid deficits present.
Fluids are a drug, so patients receiving them require careful monitoring from us. Underhydration and volume overload both have significant consequences for our patients, so fluid balance needs to be reassessed regularly, and rates adjusted as required.
IV catheters should also be handled carefully, monitored closely for signs of phlebitis, and redressed every 12 hours.
Phlebotomy
There is no reason why we can’t perform phlebotomy in these patients! To do this, you’ll need:
A large-bore butterfly needle
3-way tap
20ml syringes
Anticoagulant
Skin scrub solution
Clippers
Dressing materials
The procedure for phlebotomy in these patients is almost the same as when performing blood donation. However, we’re not going to transfuse this blood collected, it needs to be discarded. I personally still flush my line with anticoagulant though… Just in case there are any problems with blood flow through the line during the procedure.
Nutrition
Like any other chronic disease, providing adequate nutrition is a vital nursing consideration. There are generally no specific nutritional considerations in these patients. Energy requirements should be calculated in every patient, and the volumes of food offered and eaten should be recorded. Any anorexia should be promptly addressed.
Oxygenation
Oxygen therapy may be required, particularly in patients with secondary polycythemia due to cardiac or respiratory disease. You can read more about oxygen administration in our respiratory series.
Monitoring
There is a lot to monitor in the polycythemic patient, including:
Heart rate
Pulse quality
Respiratory rate, pattern and effort
SPO2
Mucous membrane colour
Capillary refill time
Neurological status
Gait and ambulation
Seizure activity
Temperature
Comfort
Inspired oxygen concentration
Temperament and stress levels
Bodyweight
PCV and total solids
The exact parameters to measure and how frequently to measure them depends on the individual patient and the reason for their polycythemia.
So that’s an overview of polycythemia - an uncommon disease, but one we get to use a lot of nursing skills with! Have you ever seen a polycythemic patient? DM me on Instagram and let me know!
And don’t forget - if you want to be first on the list for the new haematology event in May, make sure you’re signed up to the mailing list here!
References
Randolph, J. 2020. Erythrocytosis and polycythemia in animals. [On-line]. MSD Vet Manual. Available from: https://www.msdvetmanual.com/veterinary/circulatory-system/erythrocytosis-and-polycythemia/erythrocytosis-and-polycythemia-in-animals
