الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
Only 40-72% of intensive care unit (ICU) patients with homodynamic instability are able to respond to fluid loading by a significant increase in stroke volume or cardiac output.
The hemodynamic management of septic shock patients remains a complex challenge. A consensus conference report of the European Society of Intensive Care Medicine (ESICM) can provide guidance on how to perform hemodynamic monitoring in critically ill patients with circulatory shock.
However, only 40-72% of intensive care unit (ICU) patients with homodynamic instability are able to respond to fluid loading by a significant increase in stroke volume or cardiac output. Stroke volume is an important determinant of cardiac output, which is the product of stroke volume and heart rate and is also used to calculate ejection fraction (EF).
The detection of fluid responsiveness is of utmost importance in the management of patients with septic shock, answering the question “Can we improve cardiac output and hence hemodynamics by giving fluid?” Although still widely used to determine fluid therapy, cardiac filling pressures do not reliably predict responsiveness of cardiovascular parameters to fluid challenge. Mechanical ventilation induces cyclic variations in vena cava flow and diameter that are reflected in changes in aortic flow within the time frame of a few heart beats. The respiratory changes in aortic flow have previously been shown to be accurate predictors of fluid responsiveness. Assuming that mechanical insufflation induced changes in systemic venous return are more marked in hypovolemic than in normo-volemic conditions, we postulated that the variation in vena cava diameter could also be useful in identifying patients who may benefit from a volume load. During the past decade, a number of dynamic tests of volume responsiveness have been reported.
Transthoracic echocardiography (TTE) is becoming the choice of hemodynamic assessment tool in many intensive care units. It has been gaining popularity due to its noninvasiveness where the benefit far outweighs the risk. Use of respiratory IVC diameter variation or collapsibility index (IVCCI) is very popular because it is very easy to record, and needs a short learning curve, even for non-cardiologist residents or physicians.
The aim of study was to test stroke volume variation (SVV) as a predictor of fluid responsiveness in mechanically ventilated patients with septic shock and its correlation with inferior vena cava (IVC) distensibility.
This prospective study was conducted on 76 adult patients with septic shock on mechanical ventilation who was admitted to critical care medicine department in Alexandria main university hospital.
Responders: 47 severe sepsis patients with SVV ≥ 15%.
Non-responders: 29 severe sepsis patients with SVV < 15%.
All patients included in this study were subjected on admission to the following:
• Informed consent from the patients or their next of kin will be taken before enrollment to the study.
• Complete history taking of patients.
• Complete physical examination.
• Glasgow coma scale (GCS)
• Laboratory investigation and Arterial Blood Gases (ABG)
• Chest X-ray daily and Echocardiography on admission.
• Random blood sugar daily and when needed.
• Adequate sedation and muscle relaxation as patient needed
All patients were mechanically ventilated using volume controlled mode (tidal volume 8-10ml/kg, respiratory frequency 12-15 breaths/minute, positive end expiratory pressure 0-2cmH2o).
Main arterial pressure was maintained above 65 mmHg by adjusting noradrenaline (norepinephrine) dose before starting measurements.
Hemodynamic measurements were recorded in supine position.
For volume expansion, we will use 500 bolus fluids that will be administered rapidly over 10 min.
The hemodynamic variables was recorded
Maximum and minimum DIVC values over a single respiratory cycle were
measured and the DIVC variation (DDIVC) calculated as the difference between the maximum and the minimum DIVC value, normalized by the mean of the two values and expressed as a percentage.
Cardiac output was evaluated using echocardiography by measuring the diameter of the aortic orifice and the velocity time integral of aortic blood flow during end-expiration. All measurements were performed in by a single experienced operator.
Responder group included 24(51.1%) males and 23(48.9%) females and in non- responder group were 15(51.7%) and 14(48.3%) respectively. Age at responder group ranged from 42-66 with mean value 53.49±7.84 and at non-responder group ranged from 42-65 with mean value 53.93±6.27. There was no statistical significant relation between outcome and demographic data.
The relation between outcome and SOFA, SPO2 and MAP. It was found that there was statistical significant relation between outcome and also there was no statistical significant relation between outcome and SPO2 and MAP on admission. (P >
0.05), while the relation between outcome and heart rate at different period of follow up. There was statistical significant relation between outcome and heart rate at different period of follow up. (P < 0.05). Relation between outcome and respiratory rate at different period of follow up. There was statistical significant relation between outcome and respiratory rate at different period of follow up. (P < 0.05). There was statistical significant relation between outcome and pH2, PaO2 1, PaO2 2, PaCO2 2, HCO3 2 (P
< 0.05) while there was no statistical significant regarding to pH1, PaCO2 1, HCO3 1
(P > 0.05). The relation between outcome and blood gases at different period of follow up. There was statistical significant relation between outcome and SaO2 1, SaO2 2, CO