Hematopoietic Stem Cell Transplant: Electrolyte Concerns by Dr. Michelle Lee.
My name is Michelle Lee.
And I will talk to you today about bone marrow transplant-specific electrolyte issues.
Case 1: Hyponatremia.
The nurse pages.
The patient's sodium is 127.
It wasn't that low yesterday.
Can you come to look at him?
In your mind, you consider the causes of hyponatremia.
Acute causes could include an errant result, IV fluid or parenteral nutrition or medications,
volume depletion, third spacing, or SIADH.
You also consider chronic causes, like renal wasting and water intoxication.
Questions to ask on the phone or to look up: What phase of transplant is the patient in?
Is the patient undergoing conditioning, receiving high-dose chemotherapy or immunosuppression?
Has the patient received the stem cell infusion today?
Are the patient's counts in the process of falling or is the patient awaiting engraftment?
Has the patient already experienced the acute toxicities of transplant and is recovering,
approaching discharge?
Or is this a patient who's been readmitted for infection, graft versus host disease,
or dehydration?
Knowing what phase of transplant the patient is in can help you understand why the patient
should have hyponatremia.
Other questions to consider for the patient: Has the patient been urinating normally?
Does the patient have excessive output, like vomiting or diarrhea, excessive input, like
receiving hyperhydration?
Trends to evaluate for the patient include heart rate, blood pressure, respiratory rate,
oxygen saturation.
It's worth looking to see how the patient's sodium and, if checked, osms have been trending.
And it's important to know how the patient's weights and specific gravities have changed
over recent days.
This allows an appropriate assessment of fluid status.
And finally, evaluating the patient's urine output will help in the same regard.
As you go to the room to see the patient, you want to observe, is the patient awake
or asleep?
Has the patient had a recent history of vomiting, diarrhea?
Is the patient able to urinate?
Is the patient having any pain?
On the examination, you'll want to assess whether the patient responds appropriately
to questions.
Does the patient have hepatomegaly?
Any focal abdominal pain?
Does the patient have any edema?
You'll want to check the IV infusions into the patient.
You can ask the nurse: can you show me what the patient is getting now?
Studies to order include rapidly repeating the chem 10.
Obtain a VBG and lactate if there are any signs of vital sign instability.
Point of clarification.
You can also consider sending whole blood electrolytes with your VBG.
Repeat the CBC and liver function tests.
It's reasonable to check serum sodium and serum osms as well as urine sodium and osms,
and in the same vein, a serum sodium and creatinine with a urine sodium and creatinine.
A urine analysis will allow for assessment of the specific gravity and whether there
are any blood or red blood cells in the urine.
And a weight may be appropriate if there are concerns for recent changes.
Interventions to initiate include evaluating those repeat laboratory studies that should
return quickly to determine whether the sodium change is real, and that may have actually
worsened since the time of the initial check.
If the process is acute, then you must act to understand the etiology to prevent progression
and to slowly correct the course.
If there's concern for IV fluid or parenteral nutrition bag or medication side effect, then
please stop it, and call the pharmacy.
If the patient appears to have volume depletion, like a recent history of vomiting or diarrhea
or an exam with tachycardia, hypotension, or delayed capillary refill, give a normal
saline bolus of 20 cc per kilogram over 20 minutes, and monitor for improvement in vital
signs.
If there's evidence of third spacing, then consider how much excess fluid the patient
is carrying and where it is.
If the respiratory rate is increased and the oxygen saturation is decreased, it's appropriate
to worry about pulmonary edema or pleural effusions.
Obtain a chest X-ray and VBG to assess the patient's respiratory status further.
If the heart rate is increased, or heart sounds are distant, or pulses weak, it's appropriate
to worry about a pericardial effusion.
Obtain a chest X-ray and VBG and lactic acid to reassess the cardiac status.
Other causes of third spacing in transplant include sepsis or veno-occlusive disease of
the liver.
Consider further evaluation if evidence points towards those indications.
If the patient has evidence of SIADH, Syndrome of Inappropriate ADH Secretion, and a reason
for that to happen, make the patient NPO.
Call the on-call attending for help with prioritizing the intravenous intake and inform the ICU
with a plan to have 3% sodium chloride available.
Point of Clarification.
It is important to evaluate for possible causes of SIADH, which may include medications, problems
with the brain or nervous system, including encephalitis or meningitis, problems with
the lung, including pneumonia or respiratory failure, and cancer such as lymphoma or brain
tumor.
If a post-renal process, like hemorrhagic cystitis with obstruction is possible, then
a renal ultrasound may be indicated.
If the process appears chronic and the patient's vital signs and exam are normal, then calculation
of the fractional excretion of sodium can help with determining the cause of hyponatremia.
The urinalysis can be evaluated for blood or red blood cells.
If a renal process is suggested, then the IV fluids can be changed from half normal
saline to normal saline.
A review of hyponatremia in the bone marrow transplant patient includes evaluating for
acute and chronic issues.
The acute issues include an errant result, IV fluid or parenteral nutrition or medications,
volume depletion, third spacing, or SIADH.
Chronic causes include renal wasting and water intoxication.
Evaluation of hyponatremia in the bone marrow transplant patient should be performed rapidly
and lead to an intervention and appropriate follow-up.
After developing a hypothesis for why hyponatremia has occurred and making an intervention, it's
appropriate to establish a monitoring plan for following up the sodium and a chemistry
at some interval of time, like every six hours.
Case 2: Low Bicarbonate.
You receive a page from the nurse.
The patient was vomiting yesterday and now he's stooling out.
Why do you think his bicarb is 14?
For the bone marrow transplant patient with a low bicarbonate level, consider causes.
Metabolic acidosis is common due to infection, volume depletion, cardiac insufficiency, or
renal tubular acidosis.
Questions to ask on the phone or to look up: What phase of transplant is the patient in?
Has the patient been urinating?
Does the patient have a fever?
If a fever, is this a new fever or a fever that's been persistent over days?
Does the patient have excessive output, like vomiting or diarrhea?
Trends to evaluate: the heart rate, blood pressure, respiratory rate, and oxygen saturation
over days and hours, weights and specific gravities to assess the fluid status.
Observe the patient.
Is the patient comfortable?
Is the patient having increased work of breathing?
On recent history, does the patient have decreased intake either by mouth or intravenously?
Does the patient have increased output, including vomiting or stool, but also a change in urination
or skin, or other insensible losses?
Does the patient have pain?
What are the characteristics of that pain?
On exam, assess the patient's perfusion status.
Are distal pulses full?
Is capillary refill brisk?
What is the temperature and appearance of the distal extremities?
Assess the patient for sources of infection.
In addition to examining the lungs and the belly, be sure to evaluate the mouth and the
bum for signs of mucositis or other infection.
Laboratory studies to order include a VBG and lactate, repeat CBC, chem 10, liver function
tests, and urinalysis.
Consider sending blood cultures, urine culture, swab of any skin lesion or wound, or respiratory
viral workup.
Imaging studies to order include a chest X-ray with two views if the patient is safe to travel
or abdominal X-rays.
For the patient with low bicarbonate and likely infection, stabilize vital signs, obtain cultures,
and start antibiotics after considering allergies and prior infections.
For the patient with volume depletion, stabilize vital signs, estimate the fluid deficit, and
start repletion with a normal saline bolus, or increase the IV fluid rate, or plan for
stool repletion with IV fluid.
For the patient with cardiac insufficiency, monitor continuously and obtain an echo urgently.
For the patient with a more chronic picture, who may have renal tubular acidosis, consider
starting Bicitra or increasing acetate in the IV fluid or parenteral nutrition to allow
for compensation.
Red flags for the patient with low bicarbonate level in transplantation include progressive
metabolic acidosis where the inciting problem cannot be captured, progressive deterioration
of vital signs from normal, and inappropriate mental status.
For these patients, further evaluation and interventions, including ICU consultation,
may be appropriate.
In review, for the bone marrow transplant patient with low bicarbonate levels, consider
the cause that most likely is a metabolic acidosis due to infection, volume depletion,
cardiac insufficiency, or renal tubular acidosis.
It is important to rapidly evaluate and determine the cause of a low bicarbonate level.
Case 3: High CO2.
You receive a page from the nurse.
The patient had been sleeping deeply, but now she's awake and in pain.
Her O2 sat is 90%.
Can we increase her PCA and increase her supplemental oxygen?
Questions to ask on the phone: What phase of transplant is the patient in?
How many increases to the PCA have been made today?
And how much oxygen is the patient requiring?
In the room, observe the patient.
Notice the level of alertness, signs of airway obstruction, evidence of respiratory effort,
ability to cough, and control of secretions.
On examination, is the patient arousable?
On the respiratory exam, does the patient have stridor, increased work of breathing,
crackles, or wheezes?
Is the patient able to take deep breaths?
Evaluate the patient for signs of mucositis.
If the patient is receiving supplemental oxygen, remove the oxygen and evaluate the oxygen
saturation on room air.
Assess the respiratory rate and any change.
Is suction available in the room in case it's needed?
Studies to order: Send a VBG and lactate.
Repeat chem 10 and trend the bicarbonate level.
Obtain a new chest X-ray if this is a new oxygen requirement, ideally, with two views
if the patient is safe to travel to radiology.
Interventions to initiate.
For this patient, you are concerned that the PCA has contributed to hypoventilation that
has altered the patient's mental status and respiratory status.
Interventions include adjusting the continuous dose of the PCA, ensuring continuous cardiovascular
and respiratory monitoring, minimizing supplemental oxygen, and considering a VBG each morning
for tenuous patients.
Elevated CO2 level in the bone marrow transplant patient can be an unrecognized warning.
Be aware.
Consider mucositis, causing upper airway obstruction with decreased respiratory drive due to medications.
Thank you for watching this video on bone marrow transplant-specific electrolyte complications.
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