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Back pain, port-wine blood, and a conductivity of 13.2

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Back pain, port-wine blood, and a conductivity of 13.2

Mr. Lindqvist, 45, is 45 minutes into an unremarkable-looking treatment when he develops sudden low back pain, chest tightness and chills. Blood in the arterial line looks dark red, almost like port wine. His blood pressure has fallen from 150/90 to 100/60 mmHg and his pulse is 110. The machine has no alarms, but arterial pressure has drifted progressively more negative over the last ten minutes and the transmembrane pressure has been climbing. Dialysate conductivity reads 13.2 mS/cm where it usually runs near 14.0. He is on a machine fed from a loop shared with three other patients, all of whom are asymptomatic.

1. What is your leading explanation, and what do you do in the next few minutes - including whether the blood goes back?

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Leading explanation: acute hemolysis, most likely from hypotonic dialysate (conductivity 13.2 against a usual 14.0 means the proportioning is off - wrong, diluted, empty or swapped concentrate), with a possible contributing inflow restriction shown by the drifting arterial pressure and rising transmembrane pressure.

Do now:

  1. Stop the blood pump, clamp the lines, and do not rinse back. The circuit holds hemolyzed red cells and a potassium load; returning it makes a bad situation worse. Discard the circuit.
  2. Oxygen, supine position, vital signs, call the RN and provider immediately. Be prepared to transfer - severe hemolysis can progress to hyperkalemia and arrhythmia.
  3. Draw the workup: plasma free hemoglobin (or inspect spun plasma for pink/red), haptoglobin, LDH, potassium, bilirubin, CBC.
  4. Save the dialysate from the machine's sampling port and the concentrate in use, and take the machine out of service, tagged.
  5. Check the other three patients now - this may be a loop problem, not a machine problem.

Document times and findings as you go. Chills plus back pain plus dark blood plus a conductivity deviation is a hemolysis picture until proven otherwise.

2. What exactly do you check on the machine and the dialysate, and what would tell you it is a machine fault rather than a water problem?

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Machine and dialysate:

  • Concentrate jugs: correct type for the machine, not swapped, not diluted with water, not empty, correct connection. A swapped or diluted acid/bicarbonate is the classic route to hypotonic dialysate.
  • Independent conductivity reading with a calibrated meter at the machine's sample port, compared with the displayed value.
  • Alarm limits and the alarm history - were proportioning alarms overridden or silenced?
  • Proportioning pump calibration and the last service date.
  • The arterial line, needle and access for kinks, clot or infiltration (this explains the negative arterial pressure and rising TMP, but not the conductivity).

Machine versus loop: if other machines show normal conductivity and those patients are well, it is machine-specific. If more than one machine on the loop reads low, or other patients develop symptoms, treat it as a water or central proportioning problem and involve the water treatment operator and medical director. Do not restart the machine on the loop until the cause is identified and the conductivity verified by an independent meter.

3. Three other patients share the loop and are asymptomatic. What do you do about them, and how do you document and report the event?

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Asymptomatic is not the same as unaffected - hemolysis can be mild and dose-related, and symptoms lag exposure.

For the three:

  • Check each one at the chair within the next 15 minutes: back or chest pain, dyspnea, chills, a pressure drop, and the color of the blood in the arterial line.
  • Check each machine's displayed and independently measured conductivity; any deviation means that machine comes off the loop.
  • Notify the RN so the provider can decide on labs for anyone with findings, and consider labs for the whole exposed group if a water or central cause is suspected.
  • Tell them what you are checking and why. Do not reassure them that nothing happened before you know.

Documentation and reporting:

  • Chart objective findings and times: onset, symptoms, vitals, the conductivity value, interventions, notifications, patient response, and disposition.
  • File the incident report per policy and notify the medical director and water treatment operator.
  • Report under your facility's adverse-event and device-reporting procedures, and keep the machine, dialysate and concentrate samples available.
  • Feed the event into QAPI: was the concentrate swap or calibration drift preventable by a daily independent conductivity check? That is the change to test.