Clinical Application Of Critical Care Ultrasound Oriented Early Fluid Resuscitation In Septic Shock

Objective:To explore the effects of critical care ultrasound-guided early fluid resuscitation on clinical outcomes in patients with septic shock.Methods:Critically ill patients who were first diagnosed as septic shock in the Department of Critical Medicine of a third-class hospital in Guizhou Province from August2018 to December 2019,were recruited as the subjects of the study.The enrolled patients were divided into control group（goal-directed therapy,namely GDT group）and study group（critical care ultrasound,namely CCUS group）.Fluid management of the patients in the two groups were guided respectively by the measurements of conventional monitoring indicators[central venous pressure（CVP）,mean arterial pressure（MAP）,central venous oxygen saturation（SvO₂）,lactate and urine volume]and results of critical care ultrasound examination[left ventricular ejection fraction（LVEF）,mitral annular plane systolic excursion（MAPSE）,the ratio of early diastolic velocity（E wave）to late diastolic velocity（A wave）（E/A）,tricuspid annular plane systolic excursion（TAPSE）,tricuspid lateral annular systolic velocity wave（S’）,stroke volume（SV）,the diameter of the inferior vena cava（IVC）,the respiratory variability of the IVC,the B-line status of the lungs,and the renal resistance index].The relevant conventional monitoring indicators and ultrasound parameters were recorded at the time of enrollment（0h）,6h,12h,and 24h in GDT group and CCUS group,respectively.The baseline characteristics,laboratory test results,resuscitation fluid volume,resuscitation targeting rate,lactate（Lac）,lactate clearance rate（LRC）,incidence of adverse event,length of hospital stay,ICU mortality and 28-day mortality were collected from the two groups,and Statistics Software SPPS 18.0 was performed for statistical analysis to evaluate the impact of early fluid resuscitation guided by critical care ultrasound on outcomes of patients with septic shock.Results:1.143 patients with septic shock were recruited during the study period,and finally 86patients were included according to the inclusion and exclusion criteria,of which 58 were males,accounting for 67.44%.Abdomen was the most common infection site,with a mean Acute Physiology and Chronic Health Evaluation II（APACHE II）of 22.93±5.79 and a mean Sepsis-related Organ Failure Assessment（SOFA）of 12.37±3.28.The patients were divided into GDT group（n₁=44）and CCUS group（n₂=42）.There was no significant difference in baseline characteristics between the two groups（P>0.05）.2.No significant difference was found in the 6-hour resuscitation targeting rate between GDT group and CCUS group（18.18%vs.26.19%,P=0.371）.The 6-hour LRC in the CCUS group was higher than that in GDT group（23.78%vs.9.72%,P=0.010）.3.The success rate of 24-hour resuscitation in CCUS group was significantly higher than that in GDT group（45.24%vs.22.73%,P=0.027）.The cumulative fluid infusion and fluid balance at 12h and 24h in CCUS group were significantly lower than those in GDT group（P=0.047,P=0.017,P=0.040,P=0.031）.Within 24 hours of enrollment,there was no significant difference in norepinephrine dose between the two groups（P>0.05）.The incidence of tissue edema within 7 days in the GDT group was significantly higher than that in the CCUS group（P=0.039）.4.In the early stage of resuscitation（24h）,the myocardial contraction of the patients in the CCUS group was normal（LVEF,MAPSE,TAPSE and S’were all at the normal range）,but the E/A of mitral valve and tricuspid valve were less than 1,indicating that the patients with septic shock took place cardiac diastolic dysfunction earlier.5.The SV was measured by ultrasound before and after fluid challenge,and theΔSV increase was greater than 15%as the standard for fluid responsiveness in patients of CCUS group.The IVC respiratory variability≥15%was used to predict fluid responsiveness,and AUC_ROCOC was 0.838（0.697-0.978）,Youden index of 0.712,with a sensitivity of 87%and a specificity of 84%.6.In the CCUS group,the changes in lung ultrasound score and renal resistance index were not apparent within 24 hours.There was no significant difference in the incidence of AKI and the use of CRRT within 7 days between the two groups.7.There was no significant difference in 28-day mortality between the GDT group and CCUS group（38.64%vs.38.10%,P=0.959）.Logistic regression analysis showed that APACHE II score was an independent predictor of mortality at day 28 in patients with septic shock.Conclusion:1.Critical care ultrasound-guided fluid management can increase 6h LRC,improve the24-hour resuscitation targeting rate,reduce the cumulative fluid infusion within 12h and24h in patients with septic shock.2.Critical care ultrasound-guided fluid management can reduce the incidence of tissue edema within 7 days in patients with septic shock,but it has no impact on reducing the incidence of AKI and the use of CRRT.3.Critical care ultrasound can detect cardiac diastolic dysfunction earlier and optimize fluid management in patients with septic shock.4.Early fluid resuscitation has no effect on the 28-day mortality of patients with septic shock.High APACHE II may be a risk factor in death for patients with septic shock.