Pulsus alternans. A case study.

Mark Weber was a graduate student in the pediatric critical care nurse practitioner program at the University of Pennsylvania in Philadelphia when this article was written. He is now a nurse practitioner in the pediatric intensive care unit at West Virginia University Hospital in Morgantown, WV. enlarged size of the heart. Physical examination revealed diaphoresis, jugular venous distention, S3 heart sounds and a grade 1/6 systolic ejection murmur over the left lower sternal border. I.B. had a positive hepatojugular reflux and cold extremities. His heart rate was 110/min, and his blood pressure was 143/103 mm Hg. Echocardiography revealed an enlarged left ventricle, with ventricular septal bowing toward the right ventricle, severe hypokinesis of the left ventricle, severe mitral regurgitation, and a shortened ejection fraction of 0.05. I.B. was transferred to the pediatric intensive care unit for further evaluation of heart failure. He was given nitroprusside at a dose of 1 μg/kg per minute for afterload reduction and heparin at a dose of 20 IU/kg per hour to prevent thrombosis in the dilated ventricle. The healthcare team decided that he should be given nothing by mouth for 8 hours and to wait until morning before placing an arterial catheter and central venous access. Cardiorespiratory monitoring was instituted, and pulsus alternans was evident on the plethysmography waveform (Figure 1). This waveform is generated by the oxygen saturation probe; its characteristics are similar to those of an arterial waveform. The next morning, arterial and central venous catheters were placed. The arterial waveform also showed the beat-to-beat alteration found in pulsus alternans (Figure 2). As part of the diagnostic evaluation for a pheochromocytoma, a 24Mark Weber, RN, MSN, PCCNP, CCRN