Clinical Research About The Changing Trend And Correlation Analyses Of Patients’ Extravascular Lung Water During The Re-absorb Phase After Severe Burn

Background and ObjectivesThe lung is one of the earliest organs damaged in patients with severe burns, easily complicated with pulmonary edema. Generally, the incidence rate of pulmonary edema is higher at burn shock stage. Two major reasons are present. One is fluid extravasation caused by many factors lead to dramatically increased vascular permeability. Another is excess liquid injected at this stage. However, during the re-absorb phase, humor changed from positive balance to negative balance, pulmonary edema is theoretically supposed to reduce compared to burn shock stage. Conversely, observed in clinical work, extravascular lung water(EVLW) has a tendency to rise. Objectives of this study is that Using Pulse indicator Continuous Cardiac Output(Pi CCO) technology which can quantitatively monitor EVLW at bedside to explore the changing trend and correlation analyses of patients’ EVLW during the Re-absorb Phase after severe burn applied comprehensive and scientific evidence of preventing pulmonary edema.MethodsProspective observational method was applied in this study. 40 patients who was diagnosed with severe burn in intensive care unit Southwest Hospital Burns Institute were enrolled as volunteers. Then signed informed consent. Firstly, doctor connect arterial and venous catheters on patients, then we connect Pi CCO monitor and began to collect data. The data we collected including pulmonary edema related indicators, such as ELWI, PVPI, hemodynamics related indicators, such as CI, SVI, MAP, SVRI, GEDI and ITBI. We get the data of CVP form ECG. Last, we measure liver function and ELISA to quantify the serum IL-6 and IL-10.Result1. The Changing Trend of Patients’ Lung and Hemodynamic Index during the back to Absorb Phase after severe Burn1.1 EVLW and PVPIIn patients, the change of ELWI elevated during the entire measurement period. Reaching the peak at the 8th days after burn(7.67±1.59 ml/kg), and with a significantly increase when compared to day 2 at 8 day postburn(p<0.05).PVPI show a continuous downward tendency during re-absorb phase, reaching the min value at 10 day postburn(1.54±0.39 ~1.14±0.39).1.2 Hemodynamic IndexITBI and GEDI, which indicating the cardiac preload, changed in a similar trend, continuing rising to a level, then holding it(ITBI:885±201.44 ml/m2~1069±266.13 ml/m2, GEDI:708±171.53 ml/m2~866±204.79 ml/m2), and they elevated remarkably in re-absorb phase compared with shock period(p<0.01).CI and SVI, which indicating the cardiac pump function, changed in a similar dynamic change regularity compared with ITBIs and GEDIs. They elevated from the terminal of shock period to 5 days after burn, then almost maintained a level to 10 days after burn. The cardiac contractility indexes, MAP and d Pmx, without any fluctuation during the study period.SVRI, which indicating the cardiac afterload, was below the normal level during the study period, excluded the terminal of shock period, and it decreased continuously to a stable level(1470±364.71 dyn.sec.cm-5.m2~1146±209.80 dyn.sec.cm-5.m2). The SVRIs in re-absorb phase was significantly lower than that in the terminal of shock period(p<0.01).2. Correlation analysis about EVLW changing of severe burned patients in reabsorb phase2.1 The result of Unitary Linear Recursive Analysis and Correlation Analysis2.1.1 The correlation analysis of capacity index and ELWISignificant correlations were present between GEDI, ITBI and ELWI at 2 to 8 days after injury(p<0.05), there is no correlation between CVP and ELWI throughout the observation period.2.1.2 The correlation analysis of TBSA% and ELWIThere is significant correlation between TBSA% and ELWI at 3 to 9 days after injury(p< 0.05).2.1.3 Correlation analysis of IL-6, IL-10 and ELWINo significant correlation between the cell inflammatory markers such as interleukin 6(IL- 6), interleukin(IL- 10) and ELWI.2.1.4 The correlation analysis of plasma proteins levels and ELWIThere are no significant correlation between the plasma proteins levels(total protein(TP), albumin(propagated), globulin(Glb)) and ELWI.2.1.5 The correlation analysis of pre-hospital time and ELWI:A significant negative correlation was present between pre-hospital time and ELWI of the second day after injury(R=0.379, P< 0.05), determination coefficient R2 = 0.015.2.1.6 The correlation analysis of net daily fluid intake and ELWIIn re-absorb phase, net daily fluid intake as a whole is on the decline, the value of 2-5 days after injury significantly decreased; 5-8 days after injury to stabilize; 8-10 significantly decreased again after injury. Correlation analysis showed that patients with net daily fluid intake and ELWI there was no significant correlation.2.2 Multiple stepwise regression analysisTotal burn surface area and the capacity index(GEDI and ITBI) has not been eliminated in regression equation during re-absorb phase(3-8 days after burned). They belong to the independent risk factors for EVLW changing.2.3 The predicted critical burn area of abnormal reabsorb in blood vessels outside the lung water at reabsorb phase in severely burned patientsBy Receiver operater characteristic analysis shows that when TBSA% at 62.5% and 69%, the area of abnormal rate of EVLW under the ROC curve is more than 0.7, the maximum AUC is 0.73.We chose the 62% or 69% of the total burn area as basis for grouping the patients included into the study, comparing the overall average ELWI differences between groups. Results show that there is a very significant differences of overall ELWI mean between two kinds of grouping method, the P value of the group method which group by 62% of the burned area(p= 0.004) is significantly less than another group method which group by 69% of the burned area(p = 0.008).Conclusion1. The GEDV, ITBV and CO of patients continue to show an upward tendency during re-absorb phase after severe burn. Values of all time phases are greater than the upper limit of reference values. Meanwhile, the SVR presents a downward tendency.2. In compare with shock period, the EVLW of patients during re-absorb phase after severe burn presents a significant increase. The result indicated that the patients have a greater risk for pulmonary edema during re-absorb phase.3. In the existing therapy pattern, TBSA, GEDV and ITBV are independent risk factors for EVLW changing in the re-absorb phase.4. Abnormal EVLW in the re-absorb phase predict the critical TBSA is 62.5%. It suggests that doctors need to be vigilant about the patients whose TBSA reaches 60% and should monitor their EVLW and capacity(GEDV and ITBV) in the fluid therapy process; Meantime, we should undertake restrictive fluid management, by reducing the net daily fluid intake and patients’ volume load to reduce the EVLW production and prevent the occurrence of pulmonary complications.