CCHT common mistakes
CCHT · Understand the traps and how to avoid them.
When a patient becomes symptomatic during treatment, the candidate reaches for a single reflex action (giving saline, slowing the pump) before establishing what the event actually is, so hypotensive episodes, cramping, and dialysis disequilibrium syndrome get treated identically.
All three present with overlapping 'I don't feel well' complaints during the same window of treatment, and candidates memorise 'saline and slow the pump' as a universal answer because it appears in so many practice scenarios. Under time pressure, the distinguishing cues (blood pressure trend, relationship to UF rate, presence of headache/restlessness/confusion rather than diaphoresis) get skipped.
What to do instead
Before responding, run a fixed 4-point check out loud in practice: blood pressure versus baseline, current UF rate and total volume removed, ultrafiltration-to-weight ratio, and mental status/neuro complaints. Low BP with diaphoresis and a large UF volume points to hypotension; a sharply negative or falling BP with an abrupt UF goal change points to a UF-driven event; headache, nausea, restlessness or confusion in a patient with a high BUN treated with a fast blood flow points to disequilibrium, which requires slowing the blood flow and not simply volume loading. Drill 10 of these vignettes until the discrimination, not the reflex, is automatic.
The candidate accepts a numeric alarm limit as the answer about 'safe dialysate' rather than the machine's own measured value, and therefore cannot say what to do when the conductivity alarm sounds mid-treatment.
Study material for alarms is usually learned as machine-button sequences (silence, reset, resume) without the physiological reason behind the alarm. Because the alarm clears when the button is pressed, candidates learn that the alarm is a nuisance signal rather than a statement that the fluid bathing the patient's blood is wrong.
What to do instead
Anchor the alarm to its consequence: abnormal dialysate conductivity means the osmotic and electrolyte composition reaching the dialysate side of the membrane is wrong, so treatment must not be resumed and the patient must not be reconnected until the machine is corrected and the condition re-verified. In practice, state the normal dialysate conductivity range you were taught (typically about 13.5-14.5 mS/cm, machine-specific) and rehearse the sequence: stop/reset the alarm, do not override to continue, check the concentrate supply, lines and proportioning, then confirm with an independent meter before resuming. Practise explaining this to a patient in one sentence.
The candidate blames the patient or the needle for a venous pressure alarm and answers 'reposition the arm', missing that a steadily rising venous pressure with a rising TMP and falling clearance indicates clotting in the dialyzer or venous chamber.
Venous pressure and TMP are taught as two separate pieces of equipment trivia, and low-frequency alarm causes (arm position, kink) are easier to remember than the trending pattern. Candidates read a single snapshot number instead of the trend, so any high reading defaults to 'positioning'.
What to do instead
Learn the trend signature as a unit: rising venous pressure plus rising TMP plus dark or layered blood in the venous chamber and falling adequacy markers equals clot, and the response is to assess and replace rather than reposition. Practise interpreting a short trend (three readings over 20 minutes) instead of one number, and pair each alarm with the compartment it measures: pre-pump arterial pressure reflects access and arterial needle problems, venous pressure reflects the post-dialyzer return path including the venous chamber and needle, and TMP reflects the membrane itself.
The candidate treats water treatment components as a list to memorise and cannot match a component to the contaminant it removes, then answers questions about chloramine breakthrough, hardness, or RO rejection by guessing which tank is which.
The components (softener, carbon, RO, DI) are taught as a linear flow diagram, and candidates learn the order without learning the hazard each stage exists to prevent. When a question presents a failure (a positive chlorine test, a hardness breakthrough, a conductivity rise) there is no mapping from symptom back to stage.
What to do instead
Build a one-line hazard map and memorise it as cause and effect: softener removes calcium and magnesium hardness that would scale the RO; carbon removes chlorine and chloramine that would otherwise cross the membrane and cause hemolysis in the patient; RO removes dissolved ions and most remaining contaminants; DI polishes ions where used. Then learn the associated test for each: hardness testing after the softener, chlorine/chloramine testing after carbon at the frequency your facility requires and always after carbon backwash or replacement, conductivity and percent rejection for the RO. Rehearse the response to a failed chlorine test as an immediate patient safety action, not a maintenance note.
The candidate answers water and dialysate quality questions using the drinking-water standard or an infection-control intuition, rather than the separate, stricter limits that apply to dialysis water and dialysate.
Municipal drinking-water limits are widely known and sound authoritative, so they feel like a safe answer. The distinction between water used for dialysate versus water used for reprocessing versus municipal supply is rarely rehearsed, so candidates collapse them into one number.
What to do instead
Learn the categories rather than a single figure: dialysis water and dialysate are held to far tighter microbiological limits than drinking water because a patient's blood is exposed to hundreds of litres per week across a non-intact membrane barrier. Memorise the current AAMI/ANSI targets approximately as bacterial counts under 100 CFU/mL in water and under 200 CFU/mL in dialysate, with endotoxin under 0.25 EU/mL in water and under 2 EU/mL in dialysate, and confirm the exact values your program uses. When a question describes a rise in bacteria or endotoxin, answer with the response chain: culture and disinfection of the system, review of the disinfection schedule and stagnation, and notification before patient treatment resumes.
The candidate applies alcohol-based hand rub in every situation, including when hands are visibly soiled or after caring for a patient with a spore-forming organism such as Clostridioides difficile, and describes a single 'wash your hands' step instead of the specific moments.
Training distills hand hygiene into one action, and the exceptions feel like trivia rather than the point. Candidates also memorise five 'moments' as a slogan without mapping them onto the dialysis routine where cannulation, connection and disconnection are the high-risk transitions.
What to do instead
Learn the two exceptions explicitly: visible soiling or exposure to spore-formers requires soap and water with friction, because alcohol does not reliably kill spores; otherwise alcohol-based rub is acceptable and faster. Then anchor the moments to actual tasks in the shift: before touching the patient or the access, before an aseptic task such as cannulation or catheter dressing, after body fluid exposure risk, after touching the patient, and after touching the machine or the immediate surroundings. Practise narrating the moments during a mock connection so the sequence is habitual rather than recalled.
The candidate manages a catheter as though it were a fistula, cleaning the exit site and hub with the same casual technique and letting the catheter remain uncapped or open to air while switching connections.
Catheters look robust and the visible dressing makes the task feel like routine wound care, so the aseptic barrier concept is underapplied. Candidates also learn 'clean the site' without learning that the hub is the entry point for bloodstream infection and therefore requires a separate, sequenced antisepsis step.
What to do instead
Treat every catheter task as a sterile-barrier procedure: mask for patient and staff, sterile gloves, full drape, and a scrub of the hub with friction and the full dry time stated by the antiseptic manufacturer before accessing. Keep the catheter clamped and capped whenever it is disconnected, and never let an open lumen sit exposed while you reach for something. Rehearse the sequence with a timer for the dry time, because shortening the dry time is the most common silent break in technique.
The candidate answers scope-of-practice items by choosing the most clinically helpful action rather than the action permitted to the technician role, for example independently adjusting a prescription, changing a UF goal, or deciding to terminate treatment without notifying the nurse.
Exam items reward the 'best patient outcome', and candidates carry over a helpfulness instinct from the unit floor where an experienced technician may anticipate the nurse's decision. The technician role is delegated and task-specific, so the correct answer is often 'assess, act within protocol, and report' rather than 'solve'.
What to do instead
Learn the boundary as a two-part rule: technician actions are those delegated and permitted by state law and facility policy, with the nurse retaining assessment, planning and evaluation of the plan of care. For any scenario involving a change to the prescription (UF goal, sodium, dialysate composition, treatment time), a new symptom requiring clinical judgement, or a decision to stop treatment, the answer is to act within standing protocol for immediate safety and notify the registered nurse. Practise rewriting free-text vignettes into 'what can I do now' versus 'what must I report', and always include the report step in your answer.
The candidate documents by memory after the fact, records only the abnormal values, or omits the intervention-response pair, so the record shows a change but not what was done and whether it worked.
Documentation feels administrative next to hands-on skills, and during a busy shift charting is deferred and reconstructed later. Candidates also mistake brevity for professionalism and therefore strip out the very elements that show clinical reasoning.
What to do instead
Use a fixed documentation skeleton for every event: what was observed with the value and time, what was done, what the response was, and whom it was reported to. Chart in real time at the machine wherever the system allows rather than at the end of the shift, and treat machine data (pressures, UF removed, alarm history) as part of the record, not as optional detail. Practise writing three mock entries, one each for hypotension, a venous pressure alarm, and a catheter dressing change, and check each against the skeleton.
The candidate calculates ultrafiltration goal and expected fluid removal without accounting for the fluids given and returned during the treatment (prime, rinseback, saline boluses), and reports a 'goal met' that does not match the patient's actual weight change.
The arithmetic is taught once as a formula and then done mentally under time pressure. Saline given during a hypotension episode and rinseback at the end are treated as separate housekeeping rather than as volume that must be subtracted from the net removal, so the numbers look right on the machine but wrong on the scale.
What to do instead
Work every calculation through a written four-line ledger: total fluid goal, minus prime and rinseback volume, minus saline and other intake given during treatment, equals net volume the machine should remove; then verify against the pre- and post-treatment weights. Redo the ledger after any bolus, because a hypotensive event changes the plan. Practice ten calculations including one with a mid-treatment 200 mL bolus and one where the prescribed goal exceeds the patient's estimated dry weight tolerance, and always sanity-check the arithmetic against a plausible weight change in kilograms.