CCHT Patient Assessment and Monitoring 2 — Questions and Answers

Question 1: At the beginning of a hemodialysis treatment, which of the following assessments should the technician perform before initiating treatment?

Obtain post-dialysis weight only since pre-dialysis weight was measured at last treatment
Obtain vital signs, pre-dialysis weight, assess vascular access, and review the treatment prescription (Correct answer)
Obtain vital signs only; weight can be measured after treatment is initiated
Review the medication administration record only; clinical assessment is the nurse's responsibility

Correct answer: Obtain vital signs, pre-dialysis weight, assess vascular access, and review the treatment prescription

A comprehensive pre-treatment assessment includes vital signs (BP, HR, temperature, respirations), pre-treatment weight (to calculate ultrafiltration volume), vascular access assessment (bruit/thrill, appearance), and review of the treatment prescription to ensure all parameters are correct for that session.

A thorough pre-treatment assessment is the foundation of safe hemodialysis care. This assessment must occur before initiating the treatment and serves to establish a clinical baseline, identify any acute changes from the previous treatment, and verify that all prescribed parameters are appropriate. Pre-treatment vital signs include: blood pressure (supine or sitting per facility protocol, should be taken in the non-access arm whenever possible); heart rate and rhythm; temperature (fever may indicate access infection or other illness); respiratory rate and oxygen saturation if indicated. Vital signs that fall outside acceptable ranges should be reported to the nurse before treatment initiation. Pre-treatment weight is essential to calculate the ultrafiltration volume: UF volume = current weight − dry weight. This directly programs the machine's target fluid removal. Weight differences from expected (unexpectedly high or low) should be verified and the nurse notified. Vascular access assessment includes: for AV fistulas and grafts, palpating the thrill and auscultating for a bruit (absence of either indicates possible thrombosis requiring immediate reporting); inspecting the access site for redness, swelling, warmth, tenderness, drainage, or skin breakdown; for catheters, inspecting the exit site for infection signs. No patient should be connected to a machine before the access is assessed. Reviewing the treatment prescription confirms the prescribed blood flow rate, dialysate composition and flow rate, treatment time, ultrafiltration goal, and any special instructions. Any discrepancies or concerns must be resolved with the nurse before treatment begins.

Question 2: A patient's blood pressure drops from 148/88 mmHg at treatment start to 82/50 mmHg at 90 minutes into dialysis. Which parameter should the technician check first?

The dialysate temperature setting
The ultrafiltration rate and total volume removed so far (Correct answer)
The blood flow rate accuracy
The dialysate potassium concentration

Correct answer: The ultrafiltration rate and total volume removed so far

A sudden significant drop in blood pressure during dialysis is most commonly caused by aggressive ultrafiltration (removing fluid faster than the vascular refilling rate). The technician should immediately check the ultrafiltration rate and the volume already removed to determine if over-ultrafiltration is the cause.

Intradialytic hypotension (IDH) is defined as a drop in systolic blood pressure of ≥20 mmHg or to below 90 mmHg with or without symptoms. At 82/50 mmHg, this represents severe, symptomatic hypotension requiring immediate intervention. The most common cause of IDH is excess ultrafiltration—either too high a rate (fluid removed faster than plasma refilling) or too large a total volume (patient's dry weight is set too low, or IDWG was larger than expected). Checking the UF rate and volume removed first allows the technician to quickly assess whether this is the cause and immediately reduce or stop ultrafiltration as the first intervention. Other causes of IDH include: dialysate temperature too warm (vasodilation), autonomic neuropathy (diabetic patients), poor cardiac function, eating during dialysis (splanchnic vasodilation), medications taken before treatment, and the patient being at or below dry weight. These are considered after the ultrafiltration is addressed. Immediate management of severe IDH includes: place patient in Trendelenburg position, stop or reduce ultrafiltration to minimum, reduce blood flow rate, consider saline bolus (100–250 mL) per nurse's order, notify the nurse immediately, and monitor vitals every 2–5 minutes until stable. If BP does not respond to these measures or the patient develops loss of consciousness, consider emergency interventions.

Question 3: During hemodialysis, a patient complains of severe headache and nausea 2 hours into treatment. Their blood pressure is 185/110 mmHg. What complication should the technician suspect?

Hypoglycemia
Dialysis disequilibrium syndrome or hypertensive emergency (Correct answer)
Catheter infection
Phosphate binder toxicity

Correct answer: Dialysis disequilibrium syndrome or hypertensive emergency

Severe headache and nausea with hypertension during dialysis suggests either dialysis disequilibrium syndrome (from rapid urea and osmolality shifts causing cerebral edema) or a hypertensive emergency. Both require immediate nursing and physician evaluation.

The combination of severe headache, nausea, and significant hypertension during hemodialysis warrants urgent attention because it can represent two distinct but serious conditions. Dialysis Disequilibrium Syndrome (DDS) occurs when urea is removed rapidly from the blood, creating an osmotic gradient between the blood and the brain. Water moves into the relatively hypertonic brain cells, causing cerebral edema. Symptoms range from headache, nausea, and restlessness to seizures, altered consciousness, and coma in severe cases. DDS is most common in new dialysis patients or after a prolonged interval between treatments (very high pre-dialysis BUN), when urea removal is most rapid. Management includes slowing the blood flow rate and dialysate flow rate, shortening treatment time, and symptomatic care. Hypertensive emergency during dialysis can cause headache and nausea as presenting symptoms of hypertensive encephalopathy, posterior reversible encephalopathy syndrome (PRES), or—in the worst case—intracerebral hemorrhage. This requires immediate physician evaluation, blood pressure monitoring, and potential antihypertensive intervention. The technician should: immediately notify the charge nurse and physician, take vital signs including neurological assessment (ask about vision changes, confusion, weakness), position the patient comfortably, and prepare to slow or stop treatment if instructed. Do not delay physician notification trying to confirm the diagnosis—the severity of symptoms requires urgent professional evaluation.

Question 4: During a routine hemodialysis treatment, the venous pressure alarm sounds repeatedly and the reading shows persistently elevated pressure. What is the most likely cause?

The dialysate flow rate is too high
A clot or kink in the venous blood return line or access (Correct answer)
The blood pump speed is set below the prescribed rate
The dialyzer membrane has ruptured causing back-filtration

Correct answer: A clot or kink in the venous blood return line or access

Persistently elevated venous pressure indicates increased resistance in the blood return path from the dialyzer to the patient. The most common causes are a kink in the venous line, clotting in the venous line or venous needle, or outflow resistance at the vascular access (stenosis, needle malposition).

Venous pressure (also called return pressure) is monitored continuously by the dialysis machine to detect changes in resistance in the blood return path. Normal venous pressure at a blood flow rate of 300–400 mL/min is typically 100–200 mmHg, varying by blood flow rate, dialyzer, and access type. Persistently elevated venous pressure suggests increased outflow resistance, which can be caused by: a kink in the venous blood line (check line routing for bends or compression), clot formation in the venous blood line chamber (drip chamber clotting, common with inadequate anticoagulation), a partially dislodged venous needle (not fully seated in the vessel), venous needle bevel against the vessel wall (reposition needle slightly), stenosis in the AV fistula or graft outflow (a serious access problem), or catheter tip malposition or clot (common with tunneled catheters). The technician should: check the venous line for visible kinks, inspect the drip chamber for clot formation, assess needle position (in fistula/graft accesses), and notify the nurse if the pressure does not normalize with simple corrections. If venous return is obstructed and the blood pump continues to run, the extracorporeal circuit pressure will build and can cause blood line disconnection or rupture. The machine should be paused if the cause cannot be quickly identified. For catheter patients, repositioning the patient (turning, extending the arm, sitting up) may relieve catheter tip malposition. Persistent catheter venous pressure problems may require a fibrinolytic flush (per physician order) or catheter replacement.

Question 5: What does a decrease in the bruit (audible sound) of an arteriovenous fistula suggest?

The fistula has matured and is functioning optimally
Possible stenosis or early thrombosis of the fistula (Correct answer)
Increased blood flow through the fistula from high blood pressure
Normal variation that does not require reporting

Correct answer: Possible stenosis or early thrombosis of the fistula

A decrease or change in the bruit of an AV fistula—particularly a change from a soft, continuous, low-pitched bruit to a high-pitched, discontinuous, or absent sound—indicates reduced blood flow, which may be due to stenosis or early thrombosis. This is a critical finding that must be reported immediately.

AV fistula surveillance is a critical component of every dialysis treatment. A functioning AV fistula produces a characteristic bruit (the sound of turbulent blood flow, heard with a stethoscope) and thrill (the palpable vibration of the same turbulent flow). Together, these reflect the patency and flow characteristics of the fistula. A normal AV fistula bruit is continuous (heard through both systole and diastole), low-pitched to medium-pitched, and consistent from treatment to treatment. Changes that suggest impending or early access failure include: a decrease in bruit intensity or loss of continuous sound (reduced flow), a change from soft to high-pitched (stenosis with turbulent flow distal to the stenosis), intermittent rather than continuous bruit (very low flow or early stenosis), a pulsatile rather than continuous thrill (indicating outflow stenosis and high intraluminal pressure), or absence of bruit and thrill (thrombosis). These findings must be reported to the nurse and physician immediately. Access stenosis is detectable before thrombosis occurs, and elective percutaneous transluminal angioplasty (PTA) can restore blood flow and prevent access loss. If thrombosis has already occurred, the window for salvage is narrow—most fistulas require thrombectomy within 12–24 hours to have a good chance of successful restoration. The CCHT should perform and document bruit and thrill assessment at every treatment and immediately communicate changes. This is one of the most impactful contributions the CCHT makes to preserving the patient's vascular access—the patient's 'lifeline.'

Question 6: At the end of a hemodialysis treatment, which of the following assessments is essential before the patient is discharged?

Confirm the dialyzer reuse count for the next treatment
Obtain post-dialysis vital signs, post-dialysis weight, and assess the patient's clinical status for safe discharge (Correct answer)
Perform a full 12-lead ECG regardless of symptoms
Obtain a post-dialysis BUN specimen on every patient at every treatment

Correct answer: Obtain post-dialysis vital signs, post-dialysis weight, and assess the patient's clinical status for safe discharge

Essential post-treatment assessments include post-dialysis vital signs (to confirm hemodynamic stability), post-dialysis weight (to verify target weight achievement), and clinical assessment of the patient's status before they leave the facility.

The post-treatment assessment is as important as the pre-treatment assessment for ensuring patient safety. Dialysis induces significant physiological changes, and patients must be confirmed stable before departing. Post-dialysis vital signs are obtained to assess hemodynamic stability after fluid removal. Blood pressure and heart rate may be lower than pre-treatment values—blood pressure typically decreases (goal of dialysis is volume reduction), but a systolic BP below 90 mmHg or signs of orthostasis require the patient to remain in the facility until stable. Post-dialysis blood pressure is also important as a reference for managing interdialytic blood pressure. Post-dialysis weight confirms whether the ultrafiltration goal was achieved (the patient reached the target dry weight). A weight significantly above or below target prompts investigation: weight above target may indicate the treatment was cut short or ultrafiltration was reduced for clinical reasons; weight significantly below target may indicate over-dialysis. Clinical assessment includes: neurological status (patient is alert, oriented, able to ambulate safely), access site assessment (needle sites have adequate hemostasis and dressing applied), and assessment for any residual symptoms (hypotension, cramping, headache, shortness of breath). If a patient cannot safely leave independently, family/transport must be arranged or the patient may need observation. Post-BUN specimens are obtained at prescribed intervals (monthly for most patients) for Kt/V calculation but not at every treatment. ECG is not routinely performed at every treatment unless clinically indicated.

CCHT Patient Assessment and Monitoring 2

At the beginning of a hemodialysis treatment, which of the following assessments should the technician perform before initiating treatment?