DOH Dialysis Technologist oral exam prep

Knowledge: An open saline line before the blood pump sits in the negative pressure segment, so an empty bag lets the pump draw air into the circuit. Alarms reset without finding the cause are the classic chain of events behind dialysis air embolism. Air reaching the venous return travels to the right heart and lungs and causes cough, chest tightness, breathlessness, hypoxaemia and arrhythmia. In a seated patient air can also rise into the cerebral veins, and a patent foramen ovale can let it cross to the arterial side and cause stroke-like signs. Other sources include a loose arterial needle or a catheter left open.

Management: I would clamp the venous line and stop the blood pump at once, and I would not return the circuit blood, because it may contain air. I would call the nurse in charge and the nephrologist and ask for the emergency trolley. He is placed on his left side with the head down, to hold air in the right atrium and away from the pulmonary outflow and the brain. I would give 100 percent oxygen by non-rebreather mask, check pulse, pressure, saturation and consciousness every few minutes, and start CPR if he loses a normal pulse. The physician decides on hospital transfer and hyperbaric oxygen. I would keep the lines intact for inspection and take the machine out of service.

Ethics and communication: I would document the times, alarm history and findings without altering the machine log. This is a serious incident for the facility reporting system, and the repeated alarm resets are a system issue for review, not a reason to blame one colleague. The patient and family should be told honestly what happened, in line with the open disclosure principle that underpins Federal Decree-Law No. 4 of 2016 on Medical Liability.

Reference: Daugirdas JT, Blake PG, Ing TS, Handbook of Dialysis (6th ed, 2025); Renal Association Clinical Practice Guideline on Haemodialysis (Ashby D et al, BMC Nephrol 2019)

Knowledge: Intradialytic hypotension happens when fluid is removed faster than it refills from the tissues. Her ultrafiltration rate is about 1200 mL per hour, or 17 mL/kg/h, and observational data link rates above about 13 mL/kg/h with more cardiovascular events and death. Autonomic neuropathy, heart failure, antihypertensives taken before dialysis, warm dialysate and eating during the session all make it worse. Yawning, cramps and nausea are early warning signs. I keep in mind causes that need the physician: arrhythmia or acute coronary syndrome, sepsis, bleeding, a dialyser reaction and pericardial effusion. A wrong target weight is also possible if she has lost flesh weight.

Management: I would set ultrafiltration to minimum, lay her flat with the legs raised, and check blood pressure every 5 minutes. Following the unit standing order I would give a saline bolus of 100 to 250 mL through the circuit, and reduce blood flow if the pressure does not recover. I would inform the nurse in charge and the nephrologist at once, with the numbers and what I have done, and ask for an ECG if she has chest pain or an irregular pulse. Once she is stable, ultrafiltration restarts at a lower rate only on the physician's instruction. For later sessions the nephrologist may review the target weight, extend or add a session, cool the dialysate and move her antihypertensives to after dialysis. I would reinforce her fluid and salt advice.

Ethics and communication: I would explain to her calmly what is happening and why the session may be longer, and listen to her concerns. Changing the prescription, the target weight or her medicines is the physician's decision, so I report and document rather than act on my own. Every bolus, pressure reading and time goes in the treatment record, so the next team can see the pattern.

Reference: KDOQI Clinical Practice Guideline for Hemodialysis Adequacy: 2015 Update (Am J Kidney Dis 2015); Daugirdas JT, Blake PG, Ing TS, Handbook of Dialysis (6th ed, 2025)

Knowledge: A painful, enlarging swelling with a falling arterial pressure means the arterial needle has infiltrated, usually through the back wall of the vein. New fistulas have thin walls, so they are cannulated with smaller needles and lower blood flows at first. A haematoma can compress the vein and cause thrombosis, the main threat to the access. Before each cannulation I assess by look, listen and feel: a soft continuous thrill, a low pitched continuous bruit, and partial collapse when the arm is raised. A pulsatile, non collapsing vessel, a high pitched short bruit or prolonged bleeding after needle removal points to stenosis.

Management: I would stop the blood pump, clamp the line and remove the infiltrated needle, then apply gentle pressure that controls bleeding without stopping flow, and a cold pack once bleeding stops. I would check the thrill and bruit every few minutes. A new needle above the infiltration is placed only if a suitable segment exists and the senior cannulator agrees; otherwise, with the physician's approval, the session continues through his catheter. I would inform the nurse in charge and the nephrologist, and if the thrill is lost I would escalate urgently, because a clotted fistula needs intervention within hours. I would record the haematoma, needle sites and pressures, and request a fistula review if stenosis is suspected.

Ethics and communication: I would explain to him what happened, that infiltration is a known risk of new fistulas, and what we will do next, and I would apologise for the pain. If I have had repeated failed cannulations, the safe step is to ask a more experienced colleague rather than try again. The event is documented and reported through the facility system so that cannulation practice can be reviewed.

Reference: KDOQI Clinical Practice Guideline for Vascular Access: 2019 Update (Lok CE et al, Am J Kidney Dis 2020); Daugirdas JT, Blake PG, Ing TS, Handbook of Dialysis (6th ed, 2025)

Knowledge: Chloramine is added to municipal water as a disinfectant and is removed in dialysis water treatment by activated carbon, usually two tanks in series. The ISO 23500 limit for total chlorine in dialysis water is 0.1 mg/L, tested after the first tank before each shift. Because each session exposes the patient to over 100 litres of water across the dialyser membrane, chloramine causes oxidant haemolysis, methaemoglobinaemia, falling haemoglobin and resistance to erythropoietin. A dark brown sample and an unexplained haemoglobin drop fit this picture. A second tank that also fails means no reliable carbon barrier is left.

Management: I would not start any treatment, because the result after the second tank exceeds the limit. I would repeat the test with a fresh reagent to confirm, then inform the unit manager, the nurse in charge, the nephrologist on duty and the biomedical engineer at once. I would check the carbon tanks, backwash timer and inlet water, and arrange carbon replacement. Patients would be rescheduled or diverted to another unit, with the nephrologist deciding priority for those at risk of hyperkalaemia or fluid overload. I would flag the patient with the haemoglobin drop for medical review, including methaemoglobin and haemolysis screen, and check others from the same shift. Treatments restart only after a documented result below 0.1 mg/L after the first tank, with increased testing frequency as the policy requires.

Ethics and communication: Patient safety comes before keeping the schedule, so I must not run patients on unsafe water whatever the pressure. The missing result from yesterday is a serious gap that I report through the incident system, not something I fill in later. Patients affected should be told honestly by the team, and the logs, actions and times are documented as evidence of the response.

Reference: ISO 23500 series: Preparation and quality management of fluids for haemodialysis and related therapies (2019); Daugirdas JT, Blake PG, Ing TS, Handbook of Dialysis (6th ed, 2025)

Knowledge: A new hepatitis C infection in a long-term haemodialysis patient with no other exposure suggests transmission in the unit until proven otherwise. Hepatitis C spreads in dialysis units mainly through lapses in standard precautions: gloves not changed between patients, contaminated vials or medication preparation near stations, shared supplies, and surfaces not cleaned between patients. Hepatitis C does not require isolation or a dedicated machine, but it does require strict standard precautions every time. Hepatitis B surface antigen positive patients, by contrast, need a separate room with a dedicated machine, equipment and staff. Confirmation needs HCV RNA testing, and direct acting antivirals are effective in dialysis patients.

Management: I would make sure the result is passed at once to the nurse in charge, the nephrologist and the infection control team, who handle the formal notification. I would support a review of the patient's stations, machines, shifts and staff over the exposure period. Practices I would audit include hand hygiene and glove changes, cleaning of the station and machine surfaces between patients, the location of medication preparation and how multi-dose vials are used. Other HCV negative patients who shared the shifts would be tested as the team decides, and screening frequency increased. I would retrain staff and observe practice. The patient continues dialysis in the unit with strict precautions, and the nephrologist arranges confirmation and referral for antiviral treatment.

Ethics and communication: Hepatitis C is reportable under Federal Law No. 14 of 2014 on the Prevention of Communicable Diseases, and reporting follows facility policy. His result is confidential, so I would not discuss it at the stations or with other patients, in line with Federal Law No. 2 of 2019. He deserves an honest explanation from the physician that infection may have been acquired in the unit, and the investigation must focus on systems rather than blame.

Reference: CDC, Recommendations for Preventing Transmission of Infections Among Chronic Hemodialysis Patients (MMWR 2001); KDIGO 2022 Clinical Practice Guideline for the Prevention, Diagnosis, Evaluation, and Treatment of Hepatitis C in CKD (2022); Federal Law No. 14 of 2014 (UAE)

Knowledge: A potassium of 6.8 mmol/L after a missed session puts him at risk of fatal arrhythmia, and 90 minutes of dialysis may not have brought it to a safe level. Fluid overload adds the risk of pulmonary oedema. Missed and shortened sessions are linked to more hospital admissions and deaths. An adult with capacity may refuse or stop treatment even when the decision is unwise, but the decision must be informed. My role is to explain, escalate and record, not to decide for the physician or to detain him.

Management: I would ask him calmly why he needs to leave and whether a shorter extension would work, such as 30 more minutes. I would tell him clearly that his potassium is at a dangerous level and that he could collapse. I would ask the nurse in charge and the nephrologist to speak with him now, because they may offer a plan such as returning for extra dialysis tomorrow. If he still decides to go, I would complete a full rinseback, remove needles safely with good haemostasis, and check vital signs. The physician should arrange the advice and follow-up. He would sign the facility form for leaving against medical advice, and I would give written warning signs and the emergency number.

Ethics and communication: Informed consent and the right to refuse treatment follow Federal Decree-Law No. 4 of 2016 and Cabinet Resolution No. 40 of 2019. I would respect his culture and family priorities without judgement, while making sure he understands the risk. I would record the time, his words, the information given, who was informed and the treatment delivered. I would never record the full session time as delivered when it was not, because false records harm patients.

Reference: UK Kidney Association Clinical Practice Guideline: Management of Hyperkalaemia in Adults (2020, updated 2023); Federal Decree-Law No. 4 of 2016 on Medical Liability (UAE)