Urinary Disorders Q 90

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Frequent PVCs are noted on the cardiac monitor of a patient with end-stage renal disease. The priority intervention is:

  

    A. Call the doctor immediately.

    B. Give the patient IV lidocaine (Xylocaine).

    C. Prepare to defibrillate the patient.

    D. Check the patient’s latest potassium level.

    

    

Correct Answer: D. Check the patient’s latest potassium level

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The patient with ESRD may develop arrhythmias caused by hypokalemia. The incidence of PVCs, as well as complex PVCs in patients with ESRD, was comparable to that of the patients who had had myocardial infarction but was significantly higher than that found in low-risk subjects. The high incidence of complex PVCs in patients with ESRD may predispose them to increased cardiovascular death, and further investigation of this finding is indicated.

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Option A: Call the doctor after checking the patient’s potassium values. The observation that two distinct patterns of arrhythmia appearance can be identified among arrhythmic dialysis patients was first made by Abe et al. They showed patients having almost constant PCV throughout the 24-h ECG recording and patients with a marked increase during dialysis and the early post-dialysis period.

Option B: Lidocaine may be ordered if the PVCs are frequent and the patient is symptomatic. In conventional HD with constant and low potassium (range 0–2.5 mEq/l) a large amount of potassium is abruptly removed from the extracellular space. Most of this potassium originates from the cells, crosses the cell membrane, the extracellular space (the blood), and the dialysis membrane before reaching the dialysate. The depletion of the potassium reserves within the cells may have important repercussions on cardiac electrophysiology.

Option C: Potassium fluxes during HD have been associated with an increase in QT interval, an increase in the dispersion of QT, and in the inhomogeneous repolarisation revealed by the analysis of the spatial aspects of T-wave complexity. The resulting repolarization heterogeneity allows for the onset of distinctive reentrant arrhythmias, and hypokalemia may act as a triggering factor in the genesis of premature ventricular depolarisations.

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