Systolic pressure variation as a guide to fluid therapy in patients with sepsis-induced hypotension

Background: Monitoring left ventricular preload is critical to achieve adeq uate fluid resuscitation in patients with hypotension and sepsis. This pros pective study tested the correlation of the pulmonary artery occlusion pres sure, the left ventricular end-diastolic area index measured by transesopha geal echocardiography, the arterial systolic pressure variation (the differ ence between maximal and minimal systolic blood pressure values during one mechanical breath), and its delta down (dDown) component (= apneic - minimu m systolic blood pressure) with the response of cardiac output to volume ex pansion during sepsis. Methods: Preload parameters were measured at baseline and during graded vol ume expansion (increments of 500 mi) in 15 patients with sepsis-induced hyp otension who required mechanical ventilation. Each volume-loading step (VLS ) was classified as a responder (increase in stroke volume index greater th an or equal to 15%) or a nonresponder. Successive VLSs were performed until a nonresponder VLS was obtained. Results: Thirty-five VLSs (21 responders) were performed. Fluid loading cau sed an overall significant increase in pulmonary artery occlusion pressure and end-diastolic area index, and a significant decrease in systolic pressu re variation and delta down (P < 0.01). There was a significant difference between responder and nonresponder VLSs in end-diastolic area index, systol ic pressure variation, and dDown, but not in pulmonary artery occlusion pre ssure. Receiver-operator curve analysis showed that dDown was a more accura te indicator of the response of stroke volume index to volume loading than end-diastolic area index and pulmonary artery occlusion pressure. A dDown c omponent of more than 5 mmHg indicated that the stroke volume index would i ncrease in response to a subsequent fluid challenge (positive and negative predictive values: 95% and 93%, respectively). Conclusion: The dDown component of the systolic pressure variation is a sen sitive indicator of the response of cardiac output to volume infusion in pa tient with sepsis-induced hypotension who require mechanical ventilation.