End-expiratory Occlusion Test and Lung Recruitment Maneuver to Assess Fluid responsiVeness In Surgical Patients

The functional hemodynamic test (FHT) called passive leg raising (PLR) has been successfully used for assessing the fluid responsiveness in ICU patients since 2009 and its reliability has been confirmed by three large meta-analyses. However, the PLR is not usually practicable in the OR. A lot of different FHTs have been proposed, as alternative to the PLR, in ICU and, more recently, OR. These tests could be basically subdivided in two groups. A subgroup of FHTs is based on sudden and brief variations of the mechanical ventilation to induce a change in right ventricle preload and/or after load and, as consequence, of left ventricle SV. A second subgroup aims at testing the increase in SV after the rapid administration of a small aliquot of the predefined FC. Among the first group, the end-expiratory occlusion test (EEOT) and the lung recruitment maneuver (LRM) have been previously successfully tested in surgical patients. The EEOT consists of the interruption of the mechanical ventilation for 30 seconds, whereas the LRM consists in the increase in the peak inspiratory pressure up to 30 cmH20 for 30 seconds and in the assessment of the changes in the SV after the maneuvers. These tests are safe and can be easily applicable during the surgery to predict fluid responsiveness and optimize the fluid therapy. The primary aim of the present study is to compare the reliability of EEOT and LRM in predicting fluid responsiveness in patients undergoing general surgery.