Splenic Doppler Resistive Index Variation Mirrors Cardiac Responsiveness and Systemic Hemodynamics upon Fluid Challenge Resuscitation in Postoperative Mechanically Ventilated Patients

Objective. To test if splenic Doppler resistive index (SDRI) allows noninvasive monitoring of changes in stroke volume and regional splanchnic perfusion in response to fluid challenge. Design and Setting. Prospective observational study in cardiac intensive care unit. Patients. Fifty-three patients requiring mechanical ventilation and fluid challenge for hemodynamic optimization after cardiac surgery. Interventions. SDRI values were obtained before and after volume loading with 500 mL of normal saline over 20 min and compared with changes in systemic hemodynamics, determined invasively by pulmonary artery catheter, and arterial lactate concentration as expression of splanchnic perfusion. Changes in stroke volume >10% were considered representative of fluid responsiveness. Results. A <4% SDRI reduction excluded fluid responsiveness, with 100% sensitivity and 100% negative predictive value. A >9% SDRI reduction was a marker of fluid responsiveness with 100% specificity and 100% positive predictive value. A >4% SDRI reduction was always associated with an improvement of splanchnic perfusion mirrored by an increase in lactate clearance and a reduction in systemic vascular resistance, regardless of fluid responsiveness. Conclusions. This study shows that SDRI variations after fluid administration is an effective noninvasive tool to monitor systemic hemodynamics and splanchnic perfusion upon volume administration, irrespective of fluid responsiveness in mechanically ventilated patients after cardiac surgery.

Enteral feeding of intrauterine growth restriction preterm infants: theoretical risks and practical implications

Intrauterine growth restriction (IUGR) infants are thought to have impaired gut function after birth secondary to intrauterine redistribution of the blood flow, due to placental insufficiency, with a consequent reduction of gut perfusion. For this reason, infants complicated by IUGR have been considered at higher risk of feeding intolerance. Postnatal evaluation of splanchnic perfusion, through Doppler of the superior mesenteric artery, and of splanchnic oxygenation, through near infrared spectroscopy measurements, may be useful in evaluating the persistence (or not) of the redistribution of blood flow occurred <em>in utero</em>.