Impact of passive vibration on pressure pulse wave characteristics

The augmentation index (AIx), a marker of wave reflection, decreases following acute leg exercise. Passive vibration (PV) causes local vasodilation that may reduce AIx. This study investigated the effects of acute PV on wave reflection and aortic hemodynamics. In a crossover fashion 20 (M=9, F=11) healthy young (22±3 year) participants were randomized to 10 min PV or no vibration control (CON) trials. Subjects rested in the supine position with their legs over a vibration platform for the entire session. Radial waveforms were obtained by applanation tonometry before and after 3 min (Post-3) and 30 min (Post-30) of PV (∼5.37 G) or CON. No change in parameters was found at Post-3. We found significant time-by-trial interactions (P\u3c0.01) at Post-30 for augmented pressure, AIx and second systolic peak pressure (P2), such that these parameters significantly (P\u3c0.05) decreased (−2.3±3.0 mm Hg, −7.2±6.9% and −1.5±3.5 mm Hg, respectively) after PV but not after CON. These findings suggest that acute PV applied to the legs decreases AIx owing to a decrease in wave reflection magnitude (P2). Further research is warranted to evaluate the potential clinical application of PV in populations at an increased cardiovascular risk who are unable to perform conventional exercise

Huge subcutaneous extraperitoneal pseudocyst after migration of the ventriculoperitoneal shunt catheter.

The formation of an intraperitoneal pseudocyst as a complication of ventriculoperitoneal shunts is well known. However, the formation of a pseudocyst at the subcutaneous extraperitoneal abdominal space is unusual and likely secondary to the migration of the peritoneal catheter. We present a 53-year-old male who had placement of a ventriculoperitoneal shunt for hydrocephalus secondary to a vestibular schwannoma. Five months later, he presented with an enormously distended abdomen. Investigations showed the peritoneal catheter in the extraperitoneal space within a large right lower quadrant abdominal wall pseudocyst. The patient was taken to the operating theatre, and the shunt was externalised at the original abdominal incision. Approximately 3 L of cerebrospinal fluid were aspirated from the distal peritoneal catheter. After negative cultures, a new peritoneal catheter was placed intraperitoneally at the contralateral lower abdominal quadrant. The contralateral quadrant was utilised to prevent fluid accumulation into the old extraperitoneal cavity