Comparison of values in critically ill patients for global end-diastolic volume and extravascular lung water measured by transcardiopulmonary thermodilution: a meta-analysis of the literature

Validating a Simplified Lung Ultrasound Protocol for Detection and Quantification of Pulmonary Edema in Patients With Chronic Kidney Disease Receiving Maintenance Hemodialysis

OBJECTIVES

Pulmonary edema is a common clinical problem and lung ultrasound (LUS) presents an efficient method for evaluating this pathology. This study aims to investigate if a clinically efficient LUS protocol can quantify the level of extravascular lung fluid in patients receiving hemodialysis, and to develop a simplified B-line scoring system based on this protocol.

METHODS

A simple 8-area LUS approach was used for the assessment of the extravascular fluid status in patients before, during, and after receiving hemodialysis. The LUS assessments were compared to the amount of removed fluid over time. To determine the best B-line score system, different scorings for each zone were tested in a linear mixed model with pseudo R-square model fit against removed fluid. The B-line score was further validated through correlations with changes in oxygen saturation, grade of dyspnea, and body weight over time.

RESULTS

A total of 53 patients were included and examined on 108 hemodialysis occasions. Median fluid removal was 2.3 L. The B-line score model with best fit was a score of 0 points in a zone with 0 or 1 B-lines, 1 point with 2 or 3 B-lines, 2 points with 3 or more B-lines, and 3 points with any interstitial confluence. Using this B-line score, we found a significant association with amount of removed fluid, oxygen saturation, grade of dyspnea, and change in body weight.

CONCLUSION

A straightforward protocol for LUS and B-line score system was shown valid for quantification of pulmonary edema and fluid removal in hemodialysis patients. The scoring system developed here can be useful also in other patient groups, but this requires further validation.

Diagnostic value of transpulmonary thermodilution measurements for acute respiratory distress syndrome in a pig model of septic shock

BACKGROUND

No direct approach assessing pulmonary vascular permeability exists in the current therapeutic strategy for patients with acute respiratory distress syndrome (ARDS). Transpulmonary thermodilution measures hemodynamic parameters such as pulmonary vascular permeability index and extravascular lung water, enabling clinicians to assess ARDS severity. The aim of this study is to explore a precise transpulmonary thermodilution-based criteria for quantifying the severity of lung injury using a clinically relevant septic-ARDS pig model.

METHODS

Thirteen female pigs (weight: 31 ± 2 kg) were intubated, mechanically ventilated under anesthesia, and either assigned to septic shock-induced ARDS or control group. To confirm the development of ARDS, we performed computed tomography (CT) imaging in randomly selected animals. The pulmonary vascular permeability index, extravascular lung water, and other hemodynamic parameters were consecutively measured during the development of septic lung injury. Lung status was categorized as normal (partial pressure of oxygen/fraction of inspired oxygen ≥ 400), or injured at different degrees: pre-ARDS (300-400), mild-to-moderate ARDS (100-300), or severe ARDS (< 100). We also measured serum inflammatory cytokines and high mobility group box 1 levels during the experiment to explore the relationship of the pulmonary vascular permeability index with these inflammatory markers.

RESULTS

Using CT image, we verified that animals subjected to ARDS presented an extent of consolidation in bilateral gravitationally dependent gradient that expands over time, with diffuse ground-glass opacification. Further, the post-mortem histopathological analysis for lung tissue identified the key features of diffuse alveolar damage in all animals subjected to ARDS. Both pulmonary vascular permeability index and extravascular lung water increased significantly, according to disease severity. Receiver operating characteristic analysis demonstrated that a cut-off value of 3.9 for the permeability index provided optimal sensitivity and specificity for predicting severe ARDS (area under the curve: 0.99, 95% confidence interval, 0.98-1.00; sensitivity = 100%, and specificity = 92.5%). The pulmonary vascular permeability index was superior in its diagnostic value than extravascular lung water. Furthermore, the pulmonary vascular permeability index was significantly associated with multiple parameters reflecting clinicopathological changes in animals with ARDS.

CONCLUSION

The pulmonary vascular permeability index is an effective indicator to measure septic ARDS severity.

Convalescent plasma therapy in B-cell-depleted and B-cell sufficient patients with life-threatening COVID-19 - A case series

Objective

To investigate the effect of convalescent plasma therapy (CPT) on clinical courses of B-cell-sufficient and B-cell-depleted patients with life-threatening COVID-19.

Patients and Methods

In this case series, we retrospectively analysed clinical, laboratory and cardiopulmonary parameters of six patients with life-threatening COVID-19 receiving convalescent plasma (CP) as rescue therapy between April 11, 2020 to October 10, 2020. Clinical and laboratory parameters before and after transfusion were compared in two B-cell-depleted patients and four B-cell sufficient patients (control group).

Results

Both B-cell-depleted patients cleared SARS-CoV-2 virus and survived, while all other patients died within 14 days from intervention despite maximal therapeutic efforts. D-dimer levels increased in both cohorts subsequent to CPT. In control patients, mean Interleukin-6 increased and platelet levels decreased as opposed to decreasing and stable levels in B-cell-depleted patients, respectively. Control patients required increased doses of vasopressor compared to decreasing doses in B-cell depleted patients subsequent to CPT. PO₂/FiO₂ decrease was more pronounced and respiratory deterioration required postinterventional extracorporeal membrane oxygenation in two control patients. Transpulmonary thermodilution revealed a further increase of the Extravascular Lung Water Index upon CPT in control patients.

Conclusion

Use of CP in late stages of life-threatening COVID-19 should be used with caution but may be beneficial in B-cell-depleted patients. Further studies are necessary to assess factors predicting potential therapeutic benefits as well as possible hazards.

B-Lines Scores Derived From Lung Ultrasound Provide Accurate Prediction of Extravascular Lung Water Index: An Observational Study in Critically Ill Patients

Introduction:

Visualization of B-lines via lung ultrasound provides a non-invasive estimation of pulmonary hydration. Extravascular lung water index (EVLWI) and pulmonary vascular permeability index (PVPI) assessed by transpulmonary thermodilution (TPTD) represent the most validated parameters of lung water and alveolocapillary permeability, but measurement is invasive and expensive. This study aimed to compare the correlations of B-lines scores from extensive 28-sector and simplified 4-sector chest scan with EVLWI and PVPI derived from TPTD in the setting of intensive care unit (primary endpoint).

Methods:

We performed scoring of 28-sector and 4-sector B-Lines in 50 critically ill patients. TPTD was carried out with the PiCCO-2-device (Pulsion Medical Systems SE, Maquet Getinge Group). Median time exposure for ultrasound procedure was 12 minutes for 28-sector and 4 minutes for 4-sector scan.

Results:

Primarily, we found close correlations of 28-sector as well as 4-sector B-Lines scores with EVLWI (R² = 0.895 vs. R² = 0.880) and PVPI (R² = 0.760 vs. R² = 0.742). Both B-lines scores showed high accuracy to identify patients with specific levels of EVLWI and PVPI. The extensive 28-sector B-lines score revealed a moderate advantage compared to simplified 4-sector scan in detecting a normal EVLWI ≤ 7 (28-sector scan: sensitivity = 81.8%, specificity = 94.9%, AUC = 0.939 versus 4-sector scan: sensitivity = 81.8%, specificity = 82.1%, AUC = 0.902). Both protocols were approximately equivalent in prediction of lung edema with EVLWI ≥ 10 (28-sector scan: sensitivity = 88.9%, specificity = 95.7%, AUC = 0.977 versus 4-sector scan: sensitivity = 81.5%, specificity = 91.3%, AUC = 0.958) or severe pulmonary edema with EVLWI ≥ 15 (28-sector scan: sensitivity = 91.7%, specificity = 97.4%, AUC = 0.995 versus 4-sector scan: sensitivity = 91.7%, specificity = 92.1%, AUC = 0.978). As secondary endpoints, our evaluations resulted in significant associations of 28-sector as well as simplified 4-sector B-Lines score with parameters of respiratory function.

Conclusion:

Both B-line protocols provide accurate non-invasive evaluation of lung water in critically ill patients. The 28-sector scan offers a marginal advantage in prediction of pulmonary edema, but needs substantially more time than 4-sector scan.

Aortic volume determines global end-diastolic volume measured by transpulmonary thermodilution

Background

Global end-diastolic volume (GEDV) measured by transpulmonary thermodilution is regarded as indicator of cardiac preload. A bolus of cold saline injected in a central vein travels through the heart and lung, but also the aorta until detection in a femoral artery. While it is well accepted that injection in the inferior vena cava results in higher values, the impact of the aortic volume on GEDV is unknown. In this study, we hypothesized that a larger aortic volume directly translates to a numerically higher GEDV measurement.

Methods

We retrospectively analyzed data from 88 critically ill patients with thermodilution monitoring and who did require a contrast-enhanced thoraco-abdominal computed tomography scan. Aortic volumes derived from imaging were compared with GEDV measurements in temporal proximity.

Results

Median aortic volume was 194 ml (interquartile range 147 to 249 ml). Per milliliter increase of the aortic volume, we found a GEDV increase by 3.0 ml (95% CI 2.0 to 4.1 ml, p < 0.001). In case a femoral central venous line was used for saline bolus injection, GEDV raised additionally by 2.1 ml (95% CI 0.5 to 3.7 ml, p = 0.01) per ml volume of the vena cava inferior. Aortic volume explained 59.3% of the variance of thermodilution-derived GEDV. When aortic volume was included in multivariate regression, GEDV variance was unaffected by sex, age, body height, and weight.

Conclusions

Our results suggest that the aortic volume is a substantial confounding variable for GEDV measurements performed with transpulmonary thermodilution. As the aorta is anatomically located after the heart, GEDV should not be considered to reflect cardiac preload. Guiding volume management by raw or indexed reference ranges of GEDV may be misleading.

Laparoscopic cytoreductive surgery and HIPEC is effective regarding peritoneum tissue paclitaxel distribution

BACKGROUND

In some patients with peritoneal carcinomatosis, we could perform the cytoreductive surgery and the HIPEC procedure by a complete laparoscopic approach to avoid morbidity. We consider that using laparoscopic approach for performing peritoneal carcinomatosis cytoreductive surgery and HIPEC with closed CO₂ recirculation technique is possible and safe, with equal efficacy to conventional methods and hemodynamic complications.

OBJECTIVE

Monitoring the effectiveness of the drug distribution in a laparoscopic ctoreductive and HIPEC surgery group with CO₂ recirculation respect to a closed and open HIPEC group METHODS: Porcine model that included fifteen mini-pigs. Five pigs were operated with laparoscopic approach performing a pelvic and retroperitoneal lymphadenectomy. They later received a total laparoscopic closed HIPEC with CO₂ recirculation (G1). Group 2 (G2): five pigs operated by an open cytoreductive surgery and closed HIPEC technique. Group 3 (G3): five animals in which an open cytoreductive surgery and an open HIPEC technique was performed. Blood and peritoneal determinations were realized after recirculation of the drug, at 60 min using chromatographic analysis.

RESULTS

G1-G2: phrenic right peritoneum, p: 0.46. Phrenic left peritoneum, p: 0.46. Pelvic peritoneum, p: 0.17. Serum paclitaxel: p: 0.01. G1-G3: phrenic right peritoneum, p: 0.34. Phrenic left peritoneum, p: 0.34. Pelvic peritoneum, p: 0.17. Serum paclitaxel G1-G3, p: 0.02.

CONCLUSIONS

A total laparoscopic approach for ctoreductive surgery and closed HIPEC with CO₂ recirculation may be safe and feasible. In our experimental model there was no significant difference in tissue drug distribution respect the conventional techniques and there was a less toxicity because the serum drug concentration was significantly lower with laparoscopic approach respect the other groups.

Risk factors and the associated limit values for abnormal elevation of extravascular lung water in severely burned adults

BACKGROUND

Increased extravascular lung water (EVLW) correlates with pulmonary morbidity and mortality in critical illness. The extravascular lung water index (EVLWI), which reflects the degree of EVLW in an individual, increases in the fluid reabsorption stage rather than the initial resuscitation stage in severe burn cases. While many factors contribute to EVLWI variation, the risk factors contributing to its abnormal elevation in severe burns remain unclear. The aim of this study was to identify the risk factors and associated limit values for abnormal elevation of EVLWI during the fluid reabsorption stage in a cohort of severely burned adults.

METHOD

This prospective, single-center study included only adults with burn sizes≥50% of the total body surface area (TBSA) who were admitted within 24h after burn. Demographic data were collected, and transpulmonary thermodilution (TPTD) measurements and blood biochemistry tests were performed upon admission and up to day (PBD) 9. Risk factors for abnormal EVLWI were analyzed by logistic regression. Receiver operating characteristic (ROC) curves were constructed to determine the optimal cut-offs for each risk factor.

RESULTS

Seventy-two patients were ultimately enrolled, with a mean age of 40.3 years and mean burn size of 69.4% TBSA. EVLWI began to abnormally increase (>7ml/kg) on day 3 and up to PBD 9, indicating that a supranormal EVLWI developed in the fluid reabsorption stage. Several relevant factors were considered, including patient age, burn size, intrathoracic blood volume index (ITBVI), pulmonary vascular permeability index (PVPI), cardiac index (CI), systemic vascular resistance index (SVRI), serum albumin, time of first excision and grafting, and number of operations and daily fluid administration. Among these factors, we found that only burn size and ITBVI were significantly correlated with EVLWI variation and were further identified as the independent risk factors for EVLWI abnormality. ROC analysis showed that the limits for predicting a supranormal EVLWI during the fluid reabsorption stage were 65.5% TBSA for burn size and 845ml/m² for ITBVI. Patients with burn sizes or ITBVIs higher than the limit showed significantly longer mechanical ventilation time and substantially higher occurrences of acute respiratory distress syndrome (ARDS) and pneumonia within two weeks after burn.

CONCLUSIONS

Burn size and ITBVI are the independent risk factors for EVLWI abnormality during the fluid reabsorption stage in severely burned adults. The limit values for predicting a supranormal EVLWI in those patients are 65.5% TBSA for burn size and 845ml/m² for ITBVI.

Extravascular lung water measurements in acute respiratory distress syndrome: why, how, and when?

PURPOSE OF REVIEW

Increase in pulmonary vascular permeability accompanied with accumulation of excess extravascular lung water (EVLW) is the hallmark of acute respiratory distress syndrome (ARDS). Currently, EVLW and pulmonary vascular permeability index (PVPI) can be quantitatively measured using the transpulmonary thermodilution (TPTD) technique. We will clarify why, how, and when EVLW and PVPI measurements should be performed.

RECENT FINDINGS

Although the Berlin criteria of ARDS are simple and widely used, several criticisms of them have been published. The last 2 decades have witnessed the introduction and evolution of the TPTD technique for measuring EVLW and PVPI. Several publications have recommended to evaluate EVLW and the PVPI during the treatment of critically ill patients. Accurate and objective diagnoses can be made for ARDS patients using EVLW and PVPI. EVLW more than 10 ml/kg is a reasonable criterion for pulmonary edema, and EVLW more than 15 ml/kg for a severe condition. In addition to EVLW more than 10 mL/kg, PVPI more than three suggests increased vascular permeability (i.e., ARDS), and PVPI less than 2 represent normal vascular permeability (i.e., cardiogenic pulmonary edema).

SUMMARY

EVLW and PVPI measurement will open the door to future ARDS clinical practice and research, and have potential to be included in the future ARDS definition.

The Global End-Diastolic Volume (GEDV) Could Be More Appropiate to Fluid Management Than Central Venous Pressure (CVP) During Closed Hyperthermic Intrabdominal Chemotherapy with CO2 Circulation

BACKGROUND

Closed hyperthermic intraperitoneal chemotherapy (HIPEC) may increase abdominal pressure and effects of hemodynamic changes due to maintenance hyperthermia. Our aim was to analyze the safety and effectiveness of our closed technique with CO₂ circulation in management fluid status and hemodynamic parameters by means of cardiac preload control measured by Global End Diastolic Values (GEDV) and a gas exchanger.

MATERIAL AND METHODS

A Pilot Clinical Study that included 18 advanced ovarian cancer patients undergoing citoreductive surgery and HIPEC. We used a closed-perfusion system (PRS Combat®) that includes CO₂ circulation and a gas exchanger. Transpulmonary thermodilutions and hemodynamic measurements (PiCCO₂®) were performed after citoreductive surgery (Pre-HIPEC); At half time of the HIPEC (Intra-HIPEC); After HIPEC (Post-HIPEC).

RESULTS

No significant hemodynamic measurements changes in the three thermodilutions values of Cardiac Index (CI) (p = 0.227), Global End Diastolic Values (GEVD) (p = 0.966), Stroke Volume Variation (SVV) (p = 0,884) and Systemic Vascular Resistance Index (SVRI) (p = 0.082). No correlation between central venous pressure (CVP) and GEDV (Pre-HIPEC: r = 0.164, p = 0.211; Intra-HIPEC: r = 0.015, p = 0.900; Post-HIPEC: r = 0.018, p = 0.890). There was better correlation between GEDV and CI (Pre-HIPEC: r = 0.432, p = 0.071; Intra-HIPEC: r = 0.418, p = 0.074; Post-HIPEC: r = 0.411, p = 0.080).

CONCLUSIONS

Closed intrabdominal chemotherapy with CO₂ circulation model may be a safe model for HIPEC by means of a gas exchanger. GEDV and its changes significantly correlated to CI, and not observed for CVP. GEDV values may be more appropriate for monitoring cardiac preload, blood loss limitation and to predict changes in intravascular volume status during intraperitoneal chemotherapy.

Applicability of stroke volume variation in patients of a general intensive care unit: a longitudinal observational study

Sinus rhythm (SR) and controlled mechanical ventilation (CV) are mandatory for the applicability of respiratory changes of the arterial curve such as stroke volume variation (SVV) to predict fluid-responsiveness. Furthermore, several secondary limitations including tidal volumes <8 mL/kg and SVV-values within the "gray zone" of 9-13% impair prediction of fluid-responsiveness by SVV. Therefore, we investigated the prevalence of these four conditions in general ICU-patients. This longitudinal observational study analyzed a prospectively maintained haemodynamic database including 4801 transpulmonary thermodilution and pulse contour analysis measurements of 278 patients (APACHE-II 21.0 ± 7.4). The main underlying diseases were cirrhosis (32%), sepsis (28%), and ARDS (17%). The prevalence of SR and CV was only 19.4% (54/278) in the first measurements (primary endpoint), 18.8% (902/4801) in all measurements and 26.5% (9/34) in measurements with MAP < 65 mmHg and CI < 2.5 L/min/m² and vasopressor therapy. In 69.1% (192/278) of the first measurements and in 65.9% (3165/4801) of all measurements the patients had SR but did not have CV. In 1.8% (5/278) of the first measurements and in 2.5% (119/4801) of all measurements the patients had CV but lacked SR. In 9.7% (27/278) of the first measurements and in 12.8% (615/4801) of all measurements the patients did neither have SR nor CV. Only 20 of 278 (7.2%) of the first measurements and 8.2% of all measurements fulfilled both major criteria (CV, SR) and both minor criteria for the applicability of SVV. The applicability of SVV in ICU-patients is limited due to the absence of mandatory criteria during the majority of measurements.

Impact of misplaced subclavian vein catheter into jugular vein on transpulmonary thermodilution measurement variables

OBJECTIVE

The subclavian vein (SCV) is usually used to inject the indicator of cold saline for a transpulmonary thermodilution (TPTD) measurement. The SCV catheter being misplaced into the internal jugular (IJV) vein is a common occurrence. The present study explores the influence of a misplaced SCV catheter on TPTD variables.

METHODS

Thirteen severe acute pancreatitis (SAP) patients with malposition of the SCV catheter were enrolled in this study. TPTD variables including cardiac index (CI), global end-diastolic volume index (GEDVI), intrathoracic blood volume index (ITBVI), and extravascular lung water index (EVLWI) were obtained after injection of cold saline via the misplaced SCV catheter. Then, the misplaced SCV catheter was removed and IJV access was constructed for a further set of TPTD variables. Comparisons were made between the TPTD results measured through the IJV and misplaced SCV accesses.

RESULTS

A total of 104 measurements were made from TPTD curves after injection of cold saline via the IJV and misplaced SCV accesses. Bland-Altman analysis demonstrated an overestimation of +111.40 ml/m(2) (limits of agreement: 6.13 and 216.70 ml/m(2)) for GEDVI and ITBVI after a misplaced SCV injection. There were no significant influences on CI and EVLWI. The biases of +0.17 L/(min·m(2)) for CI and +0.17 ml/kg for EVLWI were revealed by Bland-Altman analysis.

CONCLUSIONS

The malposition of an SCV catheter does influence the accuracy of TPTD variables, especially GEDVI and ITBVI. The position of the SCV catheter should be confirmed by chest X-ray in order to make good use of the TPTD measurements.

Advanced Hemodynamic Management in Patients with Septic Shock

In patients with sepsis and septic shock, the hemodynamic management in both early and later phases of these "organ dysfunction syndromes" is a key therapeutic component. It needs, however, to be differentiated between "early goal-directed therapy" (EGDT) as proposed for the first 6 hours of emergency department treatment by Rivers et al. in 2001 and "hemodynamic management" using advanced hemodynamic monitoring in the intensive care unit (ICU). Recent large trials demonstrated that nowadays protocolized EGDT does not seem to be superior to "usual care" in terms of a reduction in mortality in emergency department patients with early identified septic shock who promptly receive antibiotic therapy and fluid resuscitation. "Hemodynamic management" comprises (a) making the diagnosis of septic shock as one differential diagnosis of circulatory shock, (b) assessing the hemodynamic status including the identification of therapeutic conflicts, and (c) guiding therapeutic interventions. We propose two algorithms for hemodynamic management using transpulmonary thermodilution-derived variables aiming to optimize the cardiocirculatory and pulmonary status in adult ICU patients with septic shock. The complexity and heterogeneity of patients with septic shock implies that individualized approaches for hemodynamic management are mandatory. Defining individual hemodynamic target values for patients with septic shock in different phases of the disease must be the focus of future studies.

Hemodynamic management of septic shock: is it time for "individualized goal-directed hemodynamic therapy" and for specifically targeting the microcirculation?

Septic shock is a life-threatening condition in both critically ill medical patients and surgical patients during the perioperative phase. In septic shock, specific alterations in global cardiovascular dynamics (i.e., the macrocirculation) and in the microcirculatory blood flow (i.e., the microcirculation) have been described. However, the presence and degree of microcirculatory failure are in part independent from systemic macrohemodynamic variables. Macrocirculatory and microcirculatory failure can independently induce organ dysfunction. We review current diagnostic and therapeutic approaches for the assessment and optimization of both the macrocirculation and the microcirculation in septic shock. There are various technologies for the determination of macrocirculatory hemodynamic variables. We discuss the data on early goal-directed therapy for the resuscitation of the macrocirculation. In addition, we describe the concept of "individualized goal-directed hemodynamic therapy." Technologies to assess the local microcirculation are also available. However, adequate resuscitation goals for the optimization of the microcirculation still need to be defined. At present, we are not ready to specifically monitor and target the microcirculation in clinical routine outside studies. In the future, concepts for an integrative approach for individualized hemodynamic management of the macrocirculation and in parallel the microcirculation might constitute a huge opportunity to define additional resuscitation end points in septic shock.

Cardiac preload responsiveness in children with cardiovascular dysfunction or dilated cardiomyopathy: a multicenter observational study

OBJECTIVES

To characterize cardiac preload responsiveness in pediatric patients with cardiovascular dysfunction and dilated cardiomyopathy using global end-diastolic volume index, stroke volume index, cardiac index, and extravascular lung water index.

DESIGN

Prospective multicenter observational study.

SETTING

Medical/surgical PICUs of seven Spanish University Medical Centers.

PATIENTS

Seventy-five pediatric patients (42 male, 33 female), median age 36 months (range, 1-207 mo), were divided into three groups: normal cardiovascular status, cardiovascular dysfunction, and dilated cardiomyopathy.

INTERVENTIONS

All patients received hemodynamic monitoring with PiCCO2 (Pulsion Medical System SE, Munich, Germany). We evaluated 598 transpulmonary thermodilution sets of measurements. In 40 patients, stroke volume index, cardiac index, and global end-diastolic volume index were measured before and after 66 fluid challenges and loadings to test fluid responsiveness at different preload levels.

MEASUREMENTS AND MAIN RESULTS

Global end-diastolic volume versus predicted body surface area exhibits a power-law relationship: Global end-diastolic volume = 488.8·predicted body surface area (r = 0.93). Four levels of cardiac preload were established from the resulting "normal" global end-diastolic volume index (= 488.8·predicted body surface area). Stroke volume index and cardiac index versus global end-diastolic volume index/normal global end-diastolic volume index built using a linear mixed model analysis emulated Frank-Starling curves: in cardiovascular dysfunction group, stroke volume index (geometric mean [95% CI]) was 27 mL/m (24-31 mL/m) at "≤ 0.67 times normal global end-diastolic volume index," 37 mL/m (35-40 mL/m) at "> 0.67 ≤ 1.33 times normal global end-diastolic volume index" (Δ stroke volume index = 35%; p < 0.0001; area under the receiver-operating characteristic curve = 75%), 45 mL/ m (41-49 mL/m) at "> 1.33 ≤ 1.51 times normal global end-diastolic volume index" (Δ stroke volume index = 21%; p < 0.0001; area under the receiver-operating characteristic curve = 73%), and 47 mL/m (43-51 mL/m) at "> 1.51 times normal global end-diastolic volume index" (Δ stroke volume index = 4%; p = 1; area under the receiver-operating characteristic curve = 54%). In dilated cardiomyopathy group, stroke volume index was 21 mL/m (17-26 mL/m) at "> 0.67 ≤ 1.33 times normal global end-diastolic volume index," 27 mL/m (21-34 mL/ m) at "> 1.33 ≤ 1.51 times normal global end-diastolic volume index" (Δ stroke volume index = 29%; p = 0.005; area under the receiver-operating characteristic curve = 64%), and 25 mL/m (20-32 mL/m) at "> 1.51 times normal global end-diastolic volume index" (Δ stroke volume index = -8%; p = 1; area under the receiver-operating characteristic curve = 54%).

CONCLUSIONS

This study provides "normal" values for global end-diastolic volume index and limits of cardiac preload responsiveness in pediatric patients with cardiovascular dysfunction and dilated cardiomyopathy: 1.33 times normal global end-diastolic volume index represents the upper limit of patent cardiac preload responsiveness, with the highest expected responsiveness being below 0.67 times normal global end-diastolic volume index. The maximum response of the Frank-Starling relationship and therefore the level of no additional preload reserve is 1.33 to 1.51 times normal global end-diastolic volume index. Above 1.51 times normal global end-diastolic volume index preload responsiveness is unlikely, and the risk of pulmonary edema is maximal.

Optimal range of global end-diastolic volume for fluid management after aneurysmal subarachnoid hemorrhage: a multicenter prospective cohort study

OBJECTIVES

Limited evidence supports the use of hemodynamic variables that correlate with delayed cerebral ischemia or pulmonary edema after aneurysmal subarachnoid hemorrhage. The aim of this study was to identify those hemodynamic variables that are associated with delayed cerebral ischemia and pulmonary edema after subarachnoid hemorrhage.

DESIGN

A multicenter prospective cohort study.

SETTING

Nine university hospitals in Japan.

PATIENTS

A total of 180 patients with aneurysmal subarachnoid hemorrhage.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Patients were prospectively monitored using a transpulmonary thermodilution system in the 14 days following subarachnoid hemorrhage. Delayed cerebral ischemia was developed in 35 patients (19.4%) and severe pulmonary edema was developed in 47 patients (26.1%). Using the Cox proportional hazards model, the mean global end-diastolic volume index (normal range, 680-800 mL/m) was the independent factor associated with the occurrence of delayed cerebral ischemia (hazard ratio, 0.74; 95% CI, 0.60-0.93; p = 0.008). Significant differences in global end-diastolic volume index were detected between the delayed cerebral ischemia and non-delayed cerebral ischemia groups (783 ± 25 mL/m vs 870 ± 14 mL/m; p = 0.007). The global end-diastolic volume index threshold that best correlated with delayed cerebral ischemia was less than 822 mL/m, as determined by receiver operating characteristic curves. Analysis of the Cox proportional hazards model indicated that the mean global end-diastolic volume index was the independent factor that associated with the occurrence of pulmonary edema (hazard ratio, 1.31; 95% CI, 1.02-1.71; p = 0.03). Furthermore, a significant positive correlation was identified between global end-diastolic volume index and extravascular lung water (r = 0.46; p < 0.001). The global end-diastolic volume index threshold that best correlated with severe pulmonary edema was greater than 921 mL/m.

CONCLUSIONS

Our findings suggest that global end-diastolic volume index impacts both delayed cerebral ischemia and pulmonary edema after subarachnoid hemorrhage. Maintaining global end-diastolic volume index slightly above normal levels has promise as a fluid management goal during the treatment of subarachnoid hemorrhage.

Global end-diastolic volume is an important contributor to increased extravascular lung water in patients with acute lung injury and acuterespiratory distress syndrome: a multicenter observational study

BACKGROUND

Extravascular lung water (EVLW), as measured by the thermodilution method, reflects the extent of pulmonary edema. Currently, there are no clinically effective treatments for preventing increases in pulmonary vascular permeability, a hallmark of lung pathophysiology, in patients with acute lung injury/acute respiratory distress syndrome (ALI/ARDS). In this study, we examined the contributions of hemodynamic and osmolarity factors, for which appropriate interventions are expected in critical care, to EVLW in patients with ALI/ARDS.

METHODS

We performed a subgroup analysis of a multicenter observational study of patients with acute pulmonary edema. Overall, 207 patients with ALI/ARDS were enrolled in the study. Multivariate regression analysis was used to evaluate the associations of hemodynamic and serum osmolarity parameters with the EVLW index (EVLWI; calculated as EVLW/Ideal body weight). We analyzed factors measured on the day of enrollment (day 0), and on days 1 and 2 after enrollment.

RESULTS

Multivariate regression analysis showed that global end-diastolic volume index (GEDVI) was significantly associated with EVLWI measured on days 0, 1, and 2 (P = 0.002, P < 0.001, and P = 0.003, respectively), whereas other factors were not significantly associated with EVLWI measured on all 3 days.

CONCLUSIONS

Among several hemodynamic and serum osmolarity factors that could be targets for appropriate intervention, GEDVI appears to be a key contributor to EVLWI in patients with ALI/ARDS.

TRIAL REGISTRATION

University Hospital Medical Information Network (UMIN) Clinical Trials Registry UMIN000003627.

Early intensive versus minimally invasive approach to postoperative hemodynamic management after subarachnoid hemorrhage

BACKGROUND AND PURPOSE

The results of previous studies suggest that early goal-directed fluid therapy (EGDT) reduces delayed cerebral ischemia (DCI) after aneurysmal subarachnoid hemorrhage, but the effects of EGDT on clinical outcomes are still unclear. This study aimed to determine whether EGDT improves outcomes compared with standard less-invasive hemodynamic therapy.

METHODS

This study included 160 patients treated within 24 hours after subarachnoid hemorrhage, randomized to receive either (1) EGDT guided by preload volume and cardiac output monitored by transpulmonary thermodilution (treatment group) or (2) standard therapy guided by fluid balance or central venous pressure, assisted by uncalibrated less-invasive cardiac output monitoring during hyperdynamic therapy in patients with clinical or radiological indications of DCI (control group). DCI determined by clinical or radiological findings and functional outcome determined by the modified Rankin Scale score at 3 months were compared between groups.

RESULTS

For all clinical grades combined, there were no significant differences in the rates of DCI (33% versus 42%; P=0.33) or modified Rankin Scale score of 0 to 3 at 3 months (67% versus 57%; P=0.22) between the 2 groups. For patients with poor clinical grade, those who received EGDT had a significantly lower rate of DCI (5% versus 14%; P=0.036), modified Rankin Scale score of 0 to 3 at 3 months (52% versus 36%; P=0.026), and shorter length of intensive care unit stay (14 versus 17 days; P=0.043) than those who received standard therapy.

CONCLUSIONS

EGDT is beneficial for reducing DCI and improving postoperative functional outcome in patients with poor clinical grade.

CLINICAL TRIAL REGISTRATION URL

http://www.clinicaltrials.gov. Unique identifier: UMIN000007509.

The role of invasive techniques in cardiopulmonary evaluation

PURPOSE OF REVIEW

To discuss the role of the invasive monitoring techniques pulmonary artery catheter (PAC) and transpulmonary thermodilution (TPD) for cardiopulmonary monitoring in the critically ill patient.

RECENT FINDINGS

Characterization of the nature of hemodynamic alterations and hemodynamic optimization can be achieved both with PAC and TPD. Some recent trials suggest that volumetric measurements may be preferred in conditions with preserved left ventricular systolic function, whereas pressure measurements should be preferred in patients with altered left ventricular systolic function. Extravascular lung water is strongly associated with outcome and may be used to reflect the impact of fluid management strategies. The time response of this measurement needs still to be better defined.

SUMMARY

This review highlights that PAC and TPD have an important role in cardiopulmonary monitoring of critically ill patients. Both techniques can be used efficiently to diagnose the nature of circulatory or respiratory failure and to monitor the effects of therapies. The choice of the technique should be guided by the patient's condition and the need for additional measurements rather than based on physician's preferences.

Individually optimized hemodynamic therapy reduces complications and length of stay in the intensive care unit: a prospective, randomized controlled trial

BACKGROUND

The authors hypothesized that goal-directed hemodynamic therapy, based on the combination of functional and volumetric hemodynamic parameters, improves outcome in patients with cardiac surgery. Therefore, a therapy guided by stroke volume variation, individually optimized global end-diastolic volume index, cardiac index, and mean arterial pressure was compared with an algorithm based on mean arterial pressure and central venous pressure.

METHODS

This prospective, controlled, parallel-arm, open-label trial randomized 100 coronary artery bypass grafting and/or aortic valve replacement patients to a study group (SG; n = 50) or a control group (CG; n = 50). In the SG, hemodynamic therapy was guided by stroke volume variation, optimized global end-diastolic volume index, mean arterial pressure, and cardiac index. Optimized global end-diastolic volume index was defined before and after weaning from cardiopulmonary bypass and at intensive care unit (ICU) admission. Mean arterial pressure and central venous pressure served as hemodynamic goals in the CG. Therapy was started immediately after induction of anesthesia and continued until ICU discharge criteria, serving as primary outcome parameter, were fulfilled.

RESULTS

Intraoperative need for norepinephrine was decreased in the SG with a mean (±SD) of 9.0 ± 7.6 versus 14.9 ± 11.1 µg/kg (P = 0.002). Postoperative complications (SG, 40 vs. CG, 63; P = 0.004), time to reach ICU discharge criteria (SG, 15 ± 6 h; CG, 24 ± 29 h; P < 0.001), and length of ICU stay (SG, 42 ± 19 h; CG, 62 ± 58 h; P = 0.018) were reduced in the SG.

CONCLUSION

Early goal-directed hemodynamic therapy based on cardiac index, stroke volume variation, and optimized global end-diastolic volume index reduces complications and length of ICU stay after cardiac surgery.

Limitations of global end-diastolic volume index as a parameter of cardiac preload in the early phase of severe sepsis: a subgroup analysis of a multicenter, prospective observational study

Background

In patients with severe sepsis, depression of cardiac performance is common and is often associated with left ventricular (LV) dilatation to maintain stroke volume. Although it is essential to optimize cardiac preload to maintain tissue perfusion in patients with severe sepsis, the optimal preload remains unknown. This study aimed to evaluate the reliability of global end-diastolic volume index (GEDI) as a parameter of cardiac preload in the early phase of severe sepsis.

Methods

Ninety-three mechanically ventilated patients with acute lung injury/acute respiratory distress syndrome secondary to sepsis were enrolled for subgroup analysis in a multicenter, prospective, observational study. Patients were divided into two groups—with sepsis-induced myocardial dysfunction (SIMD) and without SIMD (non-SIMD)—according to a threshold LV ejection fraction (LVEF) of 50% on the day of enrollment. Both groups were further subdivided according to a threshold stroke volume variation (SVV) of 13% as a parameter of fluid responsiveness.

Results

On the day of enrollment, there was a positive correlation (r = 0.421, p = 0.045) between GEDI and SVV in the SIMD group, whereas this paradoxical correlation was not found in the non-SIMD group and both groups on day 2. To evaluate the relationship between attainment of cardiac preload optimization and GEDI value, GEDI with SVV ≤13% and SVV >13% was compared in both the SIMD and non-SIMD groups. SVV ≤13% implies the attainment of cardiac preload optimization. Among patients with SIMD, GEDI was higher in patients with SVV >13% than in patients with SVV ≤13% on the day of enrollment (872 [785–996] mL/m² vs. 640 [597–696] mL/m²; p < 0.001); this finding differed from the generally recognized relationship between GEDI and SVV. However, GEDI was not significantly different between patients with SVV ≤13% and SVV >13% in the non-SIMD group on the day of enrollment and both groups on day 2.

Conclusions

In the early phase of severe sepsis in mechanically ventilated patients, there was no constant relationship between GEDI and fluid reserve responsiveness, irrespective of the presence of SIMD. GEDI should be used as a cardiac preload parameter with awareness of its limitations.

Quantitative diagnosis of diffuse alveolar damage using extravascular lung water

OBJECTIVES

Acute respiratory distress syndrome is characterized by diffuse alveolar damage and increased extravascular lung water levels. However, there is no threshold extravascular lung water level that can indicate diffuse alveolar damage in lungs. We aimed to determine the threshold extravascular lung water level that discriminates between normal lungs and lungs affected with diffuse alveolar damage.

DESIGN

A retrospective analysis of normal lungs and lungs affected with diffuse alveolar damage was performed.

SETTING

Normal lung cases were taken from published data. Lung cases with diffuse alveolar damage were taken from a nationwide autopsy database. All cases of autopsy followed hospital deaths in Japan from more than 800 hospitals between 2004 and 2009; complete autopsies with histopathologic examinations were performed by board-certified pathologists authorized by the Japanese Society of Pathology.

PATIENTS

Normal lungs: 534; lungs with diffuse alveolar damage: 1,688.

INTERVENTIONS

We compared the postmortem weights of both lungs between the two groups. These lung weights were converted to extravascular lung water values using a validated equation. Finally, the extravascular lung water value that indicated diffuse alveolar damage was estimated using receiver operating characteristic analysis.

MEASUREMENTS AND MAIN RESULTS

The extravascular lung water values of the lungs showing diffuse alveolar damage were approximately two-fold higher than those of normal lungs (normal group, 7.3±2.8 mL/kg vs diffuse alveolar damage group 13.7±4.5 mL/kg; p<0.001). An extravascular lung water level of 9.8 mL/kg allowed the diagnosis of diffuse alveolar damage to be established with a sensitivity of 81.3% and a specificity of 81.2% (area under the curve, 0.90; 95% CI, 0.88-0.91). An extravascular lung water level of 14.6 mL/kg represented a 99% positive predictive value.

CONCLUSIONS

This study may provide the first validated quantitative bedside diagnostic tool for diffuse alveolar damage. Extravascular lung water may allow the detection of diffuse alveolar damage and may support the clinical diagnosis of acute respiratory distress syndrome. The best extravascular lung water cut-off value to discriminate between normal lungs and lungs with diffuse alveolar damage is around 10 mL/kg.

Comparison of thermodilution measured extravascular lung water with chest radiographic assessment of pulmonary oedema in patients with acute lung injury

Background

Acute lung injury and the acute respiratory distress syndrome (ALI/ARDS) are characterized by pulmonary oedema, measured as extravascular lung water (EVLW). The chest radiograph (CXR) can potentially estimate the quantity of lung oedema while the transpulmonary thermodilution method measures the amount of EVLW. This study was designed to determine whether EVLW as estimated by a CXR score predicts EVLW measured by the thermodilution method and whether changes in EVLW by either approach predict mortality in ALI/ARDS.

Methods

Clinical data were collected within 48 hours of ALI/ARDS diagnosis and daily up to 14 days on 59 patients with ALI/ARDS. Two clinicians scored each CXR for the degree of pulmonary oedema, using a validated method. EVLW indexed to body weight was measured using the single indicator transpulmonary thermodilution technique.

Results

The CXR score had a modest, positive correlation with the EVLWI measurements (r = 0.35, p < 0.001). There was a 1.6 ml/kg increase in EVLWI per 10-point increase in the CXR score (p < 0.001, 95% confidence interval 0.92-2.35). The sensitivity of a high CXR score for predicting a high EVLWI was 93%; similarly the negative predictive value was high at 94%; the specificity (51%) and positive predictive value (50%) were lower. The CXR scores did not predict mortality but the EVLW thermodilution did predict mortality.

Conclusion

EVLW measured by CXR was modestly correlated with thermodilution measured EVLW. Unlike CXR findings, transpulmonary thermodilution EVLWI measurements over time predicted mortality in patients with ALI/ARDS.

Global end-diastolic volume increases to maintain fluid responsiveness in sepsis-induced systolic dysfunction

Background

Sepsis-induced cardiac dysfunction may limit fluid responsiveness and the mechanism thereof remains unclear. Since cardiac function may affect the relative value of cardiac filling pressures, such as the recommended central venous pressure (CVP), versus filling volumes in guiding fluid loading, we studied these parameters as determinants of fluid responsiveness, according to cardiac function.

Methods

A delta CVP-guided, 90 min colloid fluid loading protocol was performed in 16 mechanically ventilated patients with sepsis-induced hypotension and three 30 min consecutive fluid loading steps of about 450 mL per patient were evaluated. Global end-diastolic volume index (GEDVI), cardiac index (CI) and global ejection fraction (GEF) were assessed from transpulmonary dilution. Baseline and changes in CVP and GEDVI were compared among responding (CI increase ≥10% and ≥15%) and non-responding fluid loading steps, in patient with low (<20%, n = 9) and near-normal (≥20%) GEF (n = 7) at baseline.

Results

A low GEF was in line with other indices of impaired cardiac (left ventricular) function, prior to and after fluid loading. Of 48 fluid loading steps, 9 (of 27) were responding when GEF <20% and 6 (of 21) when GEF ≥20. Prior to fluid loading, CVP did not differ between responding and non-responding steps and levels attained were 23 higher in the latter, regardless of GEF (P = 0.004). Prior to fluid loading, GEDVI (and CI) was higher in responding (1007 ± 306 mL/m²) than non-responding steps (870 ± 236 mL/m²) when GEF was low (P = 0.002), but did not differ when GEF was near-normal. Increases in GEDVI were associated with increases in CI and fluid responsiveness, regardless of GEF (P < 0.001).

Conclusions

As estimated from transpulmonary dilution, about half of patients with sepsis-induced hypotension have systolic cardiac dysfunction. During dysfunction, cardiac dilation with a relatively high baseline GEDVI maintains fluid responsiveness by further dilatation (increase in GEDVI rather than of CVP) as in patients without dysfunction. Absence of fluid responsiveness during systolic cardiac dysfunction may be caused by diastolic dysfunction and/or right ventricular dysfunction.

The clinical usefulness of extravascular lung water and pulmonary vascular permeability index to diagnose and characterize pulmonary edema: a prospective multicenter study on the quantitative differential diagnostic definition for acute lung injury/acute respiratory distress syndrome

INTRODUCTION

Acute lung injury (ALI)/acute respiratory distress syndrome (ARDS) is characterized by features other than increased pulmonary vascular permeability. Pulmonary vascular permeability combined with increased extravascular lung water content has been considered a quantitative diagnostic criterion of ALI/ARDS. This prospective, multi-institutional, observational study aimed to clarify the clinical pathophysiological features of ALI/ARDS and establish its quantitative diagnostic criteria.

METHODS

The extravascular lung water index (EVLWI) and the pulmonary vascular permeability index (PVPI) were measured using the transpulmonary thermodilution method in 266 patients with PaO2/FiO2 ratio ≤ 300 mmHg and bilateral infiltration on chest radiography, in 23 ICUs of academic tertiary referral hospitals. Pulmonary edema was defined as EVLWI ≥ 10 ml/kg. Three experts retrospectively determined the pathophysiological features of respiratory insufficiency by considering the patients' history, clinical presentation, chest computed tomography and radiography, echocardiography, EVLWI and brain natriuretic peptide level, and the time course of all preceding findings under systemic and respiratory therapy.

RESULTS

Patients were divided into the following three categories on the basis of the pathophysiological diagnostic differentiation of respiratory insufficiency: ALI/ARDS, cardiogenic edema, and pleural effusion with atelectasis, which were noted in 207 patients, 26 patients, and 33 patients, respectively. EVLWI was greater in ALI/ARDS and cardiogenic edema patients than in patients with pleural effusion with atelectasis (18.5 ± 6.8, 14.4 ± 4.0, and 8.3 ± 2.1, respectively; P < 0.01). PVPI was higher in ALI/ARDS patients than in cardiogenic edema or pleural effusion with atelectasis patients (3.2 ± 1.4, 2.0 ± 0.8, and 1.6 ± 0.5; P < 0.01). In ALI/ARDS patients, EVLWI increased with increasing pulmonary vascular permeability (r = 0.729, P < 0.01) and was weakly correlated with intrathoracic blood volume (r = 0.236, P < 0.01). EVLWI was weakly correlated with the PaO2/FiO2 ratio in the ALI/ARDS and cardiogenic edema patients. A PVPI value of 2.6 to 2.85 provided a definitive diagnosis of ALI/ARDS (specificity, 0.90 to 0.95), and a value < 1.7 ruled out an ALI/ARDS diagnosis (specificity, 0.95).

CONCLUSION

PVPI may be a useful quantitative diagnostic tool for ARDS in patients with hypoxemic respiratory failure and radiographic infiltrates.

TRIAL REGISTRATION

UMIN-CTR ID UMIN000003627.