IntroductionPulse pressure variation (PPV) has been shown to predict fluid responsiveness in ventilated intensive care unit (ICU) patients. The present study was aimed at assessing the diagnostic accuracy of PPV for prediction of fluid responsiveness by using the grey zone approach in a large population.MethodsThe study pooled data of 556 patients from nine French ICUs. Hemodynamic (PPV, central venous pressure (CVP) and cardiac output) and ventilator variables were recorded. Responders were defined as patients increasing their stroke volume more than or equal to 15% after fluid challenge. The receiver operating characteristic (ROC) curve and grey zone were defined for PPV. The grey zone was evaluated according to the risk of fluid infusion in hypoxemic patients.ResultsFluid challenge led to increased stroke volume more than or equal to 15% in 267 patients (48%). The areas under the ROC curve of PPV and CVP were 0.73 (95% confidence interval (CI): 0.68 to 0.77) and 0.64 (95% CI 0.59 to 0.70), respectively (P <0.001). A grey zone of 4 to 17% (62% of patients) was found for PPV. A tidal volume more than or equal to 8 ml.kg−1 and a driving pressure (plateau pressure - PEEP) more than 20 cmH2O significantly improved the area under the ROC curve for PPV. When taking into account the risk of fluid infusion, the grey zone for PPV was 2 to 13%.ConclusionsIn ventilated ICU patients, PPV values between 4 and 17%, encountered in 62% patients exhibiting validity prerequisites, did not predict fluid responsiveness.
The concept of perioperative hemodynamic optimization was developed by Shoemaker in the early 1980s. The controversy concerning optimization of oxygen delivery persists as recent studies show that the timing of this optimization appears to be an essential factor. At the initial stage of aggression (operative period, initial phase of septic shock), optimization of volume replacement decreases morbidity and mortality, while at a later period excess volume replacement can be harmful for the patient. The aim of this article is to review the physiological methods and indications for optimization of oxygen delivery.
Polyarteritis nodosa (PAN) is a systemic necrotizing vasculitis mediated by intravascular deposition of immune complexes. We report a 55-year-old man with PAN revealed by CNS vasculitis with subarachnoid hemorrhage and brainstem vasogenic oedema, associated with essential mixed cryoglobulinemia. In spite of aggressive treatment (steroids and cyclophosphamide), the patient became tetraplegic. A pathophysiological relationship between cryoglobulin and PAN can be suspected. Mixed cryoglobulinemia may trigger vasculitis with PAN features, possibly explaining the lack of treatment response.
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