Lung Ultrasound Score and Inferior Vena Cava Diameter Compared to Pulse Pressure Variation

normal saline cyrstalloids infusion with rate of 4ml/kg /h for 3 hours

Lung ultrasound by Philips clear vue350, Philips healthcare, Andover MAO1810, USA, Machine ID:1385 will scan For each hemi-thorax 3 main areas (anterior (Ant), lateral (Lt) and posterior (Post)) marked by the para-sternal, anterior axillary and posterior axillary lines for a total of 28 sectors will be identified

The inferior vena cava was explored in the subxiphoid window in its sagittal view-just below the junction between the inferior vena cava and suprahepatic veins which lie approximately 0.5 to 3 cm from the right atrium, following the American Society of Echocardiography guidelines.; The (IVC distensibility index (dIVC) was calculated as (maximum diameter - minimum diameter)/minimum diameter.

"Regardless of CVP (i.e., during blind PLR), noninvasiveΔPLR systolic arterial pressure (SAP) more than 17% reliably identify fluid responders. During CVP-guided PLR, in case of sufficient change in CVP (at least of 2 mmHg), noninvasiveΔPLR SAP perform better (cutoff of 9%). These findings, in sedated patients who had already undergone volume expansion and/or catecholamines, have to be verified during the early phase of circulatory failure (before an arterial line)."

patients will be temporarily sedated and paralyzed and on fully controlled mechanical ventilation. No spontaneous breathing effort will be detected on the mechanical ventilator waveform monitor ensuring that the respiratory changes in arterial pressure reflected only the effects of positive pressure ventilation. Modes of ventilation is selected to volume or pressure controlled ventilation, depending on the decision of the primary physicians. A tidal volume will be not less than 8 ml/ kg (predicted body weight). The preset respiratory rate will be at 14 breath/min. Positive end expiratory pressure (PEEP) will be between 8 and 10 cmH2O. The plateau pressure was kept at below 30 cmH2O. In all patients, radial artery cannulation will be done for invasive blood pressure monitoring (using a 20 G cannula), PPV is calculated directly on Nihon Kohden monitores at base line.