Study On Factors Affecting Hemodynamic Parameters By Percutaneous Hyperthermia

Background:Hemodynamic monitoring is the cornerstone of critically ill patients. Pulmonary artery catheter was previously the standard method for hemodynamic monitoring. However, its use has been declining due to the invasiveness and high rate of complications. Considering the extravascular lung water during hemodynamic monitoring and management at the same time will be more comprehensive. Transpulmonary thermodilution technique, such as Pulse indicator continuous cardiac output (PiCCO) can measure routine hemodynamics parameters and extravascular lung water. It has been more and more widely used. But we found that some factors could impact on parameters (including hemodynamics and extravascular lung water) monitored by PiCCO in our clinical practice.Objective:In this study, we will investigate the effect of the following factors such as:different temperature indicator injection position, pleural effusion, arrhythmia on the hemodynamics parameters and extravascular lung water monitored by transpulmonary thermodilution method.Methods:1. Hemorrhagic shock of different hemodynamic conditions was established in 8 dogs. And then transpulmonary thermodilution hemodynamics parameters and extravascular lung water was monitored in different hemodynamic conditions and different temperature indicator injection path. One injection path was through internal jugular vein (superior vena cava system) and another path was through femoral vein (inferior vena cava system). The changes of hemodynamics parameters in the two methods were analyzed.2. Acute respiratory distress syndrome (ARDS) was induced by intravenous injection with oleic acid in 6 pigs. Extravascular lung water (EVLW) was measured by PiCCO monitor (PULSION, Germany) before and immediately after the intratracheal introduction of normal saline solution into the alveolar cavity. Similarly EVLW was also measured before and immediately after the introduction of normal saline solution into the pleural cavity.3.12 patients from emergency intensive care unit with paroxysmal atrial fibrillation were enrolled. The hemodynamic parameters such as heart rate (HR), mean arterial pressure (MAP), cardiac index (CI), systemic vascular resistance index (SVRI), intrathoracic blood volume index(ITBI), extravascular lung water index(EVLWI) were monitored by transpulmonary thermodilution method before paroxysmal atrial fibrillation and during atrial fibrillation, the number of B-lines was detected by lung ultrasonography before and during paroxysmal atrial fibrillation. The changes of all the parameters were analyzed.Results:1. Both CI and GEDVI gradually declined along with blood volume declined. There were significant differences in CI and GEDVI between the four stages of different hemodynamic conditions and the baseline (P<0.05); Compared with the baseline, SVRI significantly rose (P<0.05); while EVLWI didn’t change significantly. There was no significant difference in CI, and SVRI at all the four stages (P>0.05); GEDVI monitored in the inferior vena cava group was significantly higher than the superior vena cava group (overestimating more than 20-25%) (P<0.05), EVLWI monitored in the inferior vena cava group was slightly more than the superior vena cava group, but there was no statistically significant difference between the two groups (P>0.05).2. The EVLW of the baseline was 276.6±10.8ml, while the EVLW of the ARDS models was 378.9±12.2ml, there is significant difference (P<0.001); The change of EVLW between before and immediately after the intratracheal injection (AEVLW) was similar to the volume of normal saline introduced. There is a good correlation between them (r=0.973,P<0.001); While there was no difference in △EVLW between before and immediately after the introduction into the pleural cavity (P>0.05)3. When the paroxysmal atrial fibrillation happened, the heart rate increased significantly (123.3±20 bpm vs 98.9±12.3 bpm,P=0.006); the mean arterial pressure (86.9±10.2 mmHg vs 93.0±12.5 mmHg, P=0.058), CI (2.82±0.62 L/min/m2 vs 3.31±1.02 L/min/m2,P=0.058) and SVRI (2254±947 dyn·s·cm-5·m2 vs 2302±828 dyn·s·cm-5·m2, P=0.351) had no obvious change; but ITBI significantly increased (1333±90 ml/m2 vs 937±111 ml/m2,P<0.001); EVLWI also increased significantly (16.1±1.1 ml/kg vs 6.5±1.9 ml/kg, P<0.001); No significant difference was found in the number of B-lines detected by lung ultrasonography before and during atrial fibrillation (10.0±4.2 vs 9.4±4.4, P=0.180).Conclusions:1. Cardiac output monitored in the inferior vena cava group was similar to the superior vena cava group, while GEDVI and EVLWI was overestimated in the inferior vena cava group.2. Transpulmonary thermodilution technique is an accurate method for quantification of EVLW, and pleural effusion has no effect on the accuracy of of EVLW.3. Both intrathoracic bood volume and extravascular lung water monitored by transpulmonary thermodilution method was interfered by paroxysmal atrial fibrillation, the influence maybe mislead clinical judgment and decision making.