الفهرس 
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Abstract
The widely accepted rationale behind fluid resuscitation in septic shock is to improve COP and organ perfusion, thereby limiting organ dysfunction. Logically, therefore, the only reason to resuscitate a patient with fluid would be to cause a clinically significant increase in SV. A patient whose SV increases by 10–15% after a fluid challenge (250–500 ml) is considered to be a fluid responder. Nonetheless, according to the Frank-Starling principle, as the preload increases, SV increases until the optimal preload is achieved, at which point the SV remains relatively constant. If the fluid challenge does not increase SV, volume loading serves the patient no useful benefit and is likely harmful.
The adverse effects of fluid loading when a patient is on the flat portion of the Frank-Starling curve, is related to the curvilinear shape of the left ventricular pressure-volume curve, resulting from altered diastolic compliance at higher filing pressures. As the patient reaches the plateau of his/her Frank-Starling curve, atrial pressures increase, increasing venous and pulmonary hydrostatic pressures which combined with the increased release of natriuretic peptides, causes a shift of fluid into the interstitial space, with an increase in pulmonary and tissue edema. Tissue edema impairs oxygen and metabolite diffusion, distorts tissue architecture, impedes capillary blood flow and lymphatic drainage and disturbs cell-cell interactions. Therefore, Initial fluid resuscitation should be limited and guided by an assessment of fluid responsiveness.
Therefore the present study was conducted to test the efficacy of ∆DIJV as FR parameter in management of mechanically ventilated septic shock patients, and to test the correlation between ∆DIJV and ∆DIVC.
The study was conducted on 34 adult mechanically ventilated patients admitted to Critical Care Department in Alexandria Main University Hospital with the diagnosis of septic shock or developed septic shock during their stay in the ICU after admission for other reasons.
All patients in the study were sedated using midazolam to suppress any spontaneous breathing activity during the TTE study. If the spontaneous breathing activity did not disappear, skeletal muscle relaxant used as bolus intravenous dose to make temporary skeletal muscle paralysis.
The patients in the study were mechanically ventilated by SIMV mode with tidal volume of 8 ml/kg of predicted BW provided that plateau pressure did not exceed 30 centimeter water (cm H2O). Inspiratory/expiratory time ratio was adjusted to be 1:2 to 1:3. PEEP was applied within the range of 3 to 7 cm H2O. This mode and its settings were applied mainly during the TTE study time and were not changed during echocardiography study time.
Patients were divided into two groups; R, if CI increased of more than or equal to 15% after a 7 ml/kg crystalloid infusion over half an hour, and NR if CI increased less than 15% or did not increase.
∆DIJV before fluid bolus ranged from 8.30 - 80.0% with a mean 32.67 ± 23.01% in R, while in NR it ranged from 2.50 - 42.80% with a mean 9.46 ± 10.77%.These results showed that, ∆DIJV significantly higher in R than NR (p value <0.001).
∆DIJV after fluid bolus ranged from 2.30 – 40.0% with a mean 14.51 ± 10.57% in R, while in NR it ranged from 2.40 – 48.20% with a mean 11.41 ± 12.78%. These results showed that, ∆DIVC was significantly higher in R than NR (p value <0.001).
R group showed significant change in ∆DIJV after fluid bolus (p= 0.001), but NR group showed no significant change in ∆DIJV after fluid bolus (p= 0.118).
ROC curve was constructed to evaluate the ability of ∆DIVC and ∆DIJV to predict FR in intubated sedated septic shock patients. As regards ∆DIVC the AUC was 0.940 (p<0.001). The best cut off value was ≤13.6 with sensitivity, specificity, PPV, and NPV was 94.74%, 80.00%, 85.7%, 92.3 %respectively. As regards ∆DIJV the AUC was 0.900 (p<0.001). The best cut off value was ≤11.6 with sensitivity, specificity, PPV, and NPV was 84.21%, 80.00%, 84.2%, 80.0% respectively.
We concluded that
• Ultrasonic evaluation of respirophasic changes of IJV is a simple, easy, and readily accessible bedside measure of FR in mechanically ventilated sedated septic shock patients.
• ∆DIJV can predict FR with good sensitivity, specificity and overall accuracy. Meanwhile, ∆DIVC index is still more sensitive with better overall accuracy.
We recommend that
• Transthoracic echocardiographic assessment of FR can be an integral part in the management of septic shock patients during the first 24 hours.
• All intensivists should be acquainted with the basics of echocardiography to be able to use it as a helping tool in decision making during management of septic shock patients.
• The study should be conducted on a larger scale including larger number of cases.
• Further studies should be conducted on the quantitative resuscitation of septic shock to determine better endpoints or goals to be targeted and the exact time window through which these goals should be accomplished.
• The role of echocardiography should be further investigated in the early septic shock management (including the first six hours) on larger scale.