Tag Archives: Hemodynamics

Hemodynamic Bedside Ultrasound Image Quality and Interpretation After Implementation of a Training Curriculum for Pediatric Critical Care Medicine Providers. (Williams)

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Conlon TW, Ishizuka M, Himebauch AS, Cohen MS, Berg RA, Nishisaki A. Hemodynamic Bedside Ultrasound Image Quality and Interpretation After Implementation of a Training Curriculum for Pediatric Critical Care Medicine Providers. Pediatr Crit Care Med. 2016 Jul;17(7):598-604.

OBJECTIVE: Bedside ultrasound for hemodynamic evaluation in critically ill children is increasingly recognized as an important skill for pediatric critical care medicine providers. Our institution implemented a training curriculum leading to institutional credentialing for pediatric critical care providers in nonprocedural bedside ultrasound core applications. We hypothesized that hemodynamic studies performed or supervised by credentialed providers (credentialed providers group) have better image quality and greater accuracy in interpretation than studies performed by non-credentialed providers without supervision (non-credentialed providers group).

DESIGN: Retrospective descriptive study.

SETTING: Single-center tertiary non-cardiac 55-bed PICU in a children’s hospital.

PATIENTS: Patients from October 2013 to January 2015, with hemodynamic bedside ultrasound performed and interpreted by pediatric critical care providers exposed to bedside ultrasound training.

INTERVENTIONS: A cardiologist blinded to performer scored hemodynamic bedside ultrasound image quality for five core cardiac views (excellent = 3, good = 2, fair = 1, unacceptable = 0; median = quality score) and interpretation within 5 hemodynamic domains (agreement = 3, minor disagreement = 2, major disagreement = 1; median = interpretation score), as well as a global assessment of interpretation.

MEASUREMENTS AND MAIN RESULTS: Eighty-one studies (45 in the credentialed providers group and 36 in the non-credentialed providers group) were evaluated. There was no statistically significant difference in quality score between groups (median: 1.4 [interquartile range: 0.8-1.8] vs median: 1.2 [interquartile range: 0.75-1.6]; p = 0.14]. Studies in the credentialed providers group had higher interpretation score than those in the non-credentialed providers group (median: 3 [interquartile range: 2.5-3) vs median: 2.67 [interquartile range: 2.25-3]; p = 0.04). Major disagreement between critical care provider and cardiology review occurred in 25 of 283 hemodynamic domains assessed (8.8%), with no statistically significant difference between credentialed providers and non-credentialed providers groups (6.1% vs 11.9%; p = 0.12).

CONCLUSION: Hemodynamic bedside ultrasound performed or supervised by credentialed pediatric critical care providers had more accurate interpretation than studies performed by unsupervised non-credentialed providers. A rigorous pediatric critical care medicine bedside ultrasound credentialing program can train intensivists to attain adequate images and interpret those images appropriately.

High-volume hemofiltration in children with acute liver failure. (Williams)

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Chevret L, Durand P, Lambert J, Essouri S, Balu L, Devictor D, Tissieres P. High-volume hemofiltration in children with acute liver failure*. Pediatr Crit Care Med. 2014 Sep;15(7):e300-5.

*Editorial.

Full-text for Children’s and Emory users.

OBJECTIVES: High-volume hemofiltration has shown beneficial effects in severe sepsis and multiple organ failure, improving hemodynamics and fluid balance. Recent studies suggest that acute liver failure shares many pathophysiologic similarities with sepsis. Therefore, we assessed the systemic effects of high-volume hemofiltration inchildren with acute liver failure.

DESIGN: Retrospective observational cohort study.

PATIENTS: Twenty-two children.

SETTING: Forty-two-bed multidisciplinary pediatric and neonatal ICUs in a tertiary university hospital.

INTERVENTION: We evaluated high-volume hemofiltration therapy as part of standard management of 22 childrenadmitted in our unit for acute liver failure. Fifteen patients had fulminant hepatic failure, three had acute-on-chronic liver disease, and four had primary nonfunction. High-volume hemofiltration was initiated in patients requiring emergency liver transplantation and when hepatic encephalopathy grade higher than 2 and/or hemodynamic instability requiring vasopressors occurred. High-volume hemofiltration was defined by a flow of ultrafiltrate of more than 80 mL/kg/hr. Clinical and biological variables were assessed before and 24 and 48 hours after initiation of high-volume hemofiltrationtherapy.

MEASUREMENTS AND MAIN RESULTS: High-volume hemofiltration was initiated with a median grade III of hepatic encephalopathy. The median flow of ultrafiltrate was 119 mL/kg/hr (range, 80-384). After 24 hours of high-volumehemofiltration treatment, we observed an increase in mean arterial pressure (p = 0.0002) and a decrease in serum creatinine (p = 0.0002). In half of the patients, the encephalopathy grade decreased. After 48 hours of treatment, mean arterial pressure (p = 0.0005), grade of hepatic encephalopathy (p = 0.04), and serum creatinine (p = 0.0002) improved. Overall mortality was 45.4% (n = 10). Emergency liver transplantation was performed in eight children. Five patients spontaneously recovered liver function.

CONCLUSIONS: High-volume hemofiltration therapy significantly improves hemodynamic stability and neurological status in children with acute liver failure awaiting for emergency liver transplantation.

Mechanical ventilation-induced intrathoracic pressure distribution and heart-lung interactions. (Dugan)

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Lansdorp B, Hofhuizen C, van Lavieren M, van Swieten H, Lemson J, van Putten MJ, van der Hoeven JG, Pickkers P. Mechanical ventilation-induced intrathoracic pressure distribution and heart-lung interactions*. Crit Care Med. 2014 Sep;42(9):1983-90.

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OBJECTIVE: Mechanical ventilation causes cyclic changes in the heart’s preload and afterload, thereby influencing the circulation. However, our understanding of the exact physiology of this cardiopulmonary interaction is limited. We aimed to thoroughly determine airway pressure distribution, how this is influenced by tidal volume and chest compliance, and its interaction with the circulation in humans during mechanical ventilation.

DESIGN: Intervention study.

SETTING: ICU of a university hospital.

PATIENTS: Twenty mechanically ventilated patients following coronary artery bypass grafting surgery.

INTERVENTION: Patients were monitored during controlled mechanical ventilation at tidal volumes of 4, 6, 8, and 10 mL/kg with normal and decreased chest compliance (by elastic binding of the thorax).

MEASUREMENTS AND MAIN RESULTS: Central venous pressure, airway pressure, pericardial pressure, and pleural pressure; pulse pressure variations, systolic pressure variations, and stroke volume variations; and cardiac output were obtained during controlled mechanical ventilation at tidal volume of 4, 6, 8, and 10 mL/kg with normal and decreased chest compliance. With increasing tidal volume (4, 6, 8, and 10 mL/kg), the change in intrathoracic pressures increased linearly with 0.9 ± 0.2, 0.5 ± 0.3, 0.3 ± 0.1, and 0.3 ± 0.1 mm Hg/mL/kg for airway pressure, pleural pressure, pericardial pressure, and central venous pressure, respectively. At 8 mL/kg, a decrease in chest compliance (from 0.12 ± 0.07 to 0.09 ± 0.03 L/cm H2O) resulted in an increase in change in airway pressure, change in pleural pressure, change in pericardial pressure, and change in central venous pressure of 1.1 ± 0.7, 1.1 ± 0.8, 0.7 ± 0.4, and 0.8 ± 0.4 mm Hg, respectively. Furthermore, increased tidal volume and decreased chest compliance decreased stroke volume and increased arterial pressure variations. Transmural pressure of the superior vena cava decreased during inspiration, whereas the transmural pressure of the right atrium did not change.

CONCLUSIONS: Increased tidal volume and decreased chest wall compliance both increase the change in intrathoracic pressures and the value of the dynamic indices during mechanical ventilation. Additionally, the transmural pressure of the vena cava is decreased, whereas the transmural pressure of the right atrium is not changed.

 

The short-term prognosis of cardiogenic shock can be determined using hemodynamic variables: a retrospective cohort study. (Dugan)

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Rigamonti F, Graf G, Merlani P, Bendjelid K. The short-term prognosis of cardiogenic shock can be determined using hemodynamic variables: a retrospective cohort study*. Crit Care Med. 2013 Nov;41(11):2484-91.

OBJECTIVES: Few reports address the relationship between hemodynamic variables and the cardiogenic shock outcome in critically ill patients. The present study aimed to investigate the association between hemodynamic variables and early cardiogenic shock mortality in critically ill patients.

DESIGN: Retrospective, single-center cohort study.

SETTING: Tertiary academic hospital’s 36-bed multidisciplinary intensive care.

PATIENTS: Initial presentation with cardiogenic shock.

MEASUREMENTS AND MAIN RESULTS: The authors retrospectively analyzed medical information and the hemodynamic variables (recorded during the first 24 hr following admission to the ICU) of patients with cardiogenic shock. For all the patients, the Simplified Acute Physiology Score II, cardiac index, cardiac power index, and continuous hemodynamic values following the first 24 hours of admission were reviewed. Mortality within 28 days was the primary endpoint. All the variables were then compared with survival and nonsurvival status and those variables with a significant association in the univariate analysis were entered into a multivariate logistic regression model. Seventy-one patients were included. Among them, 26 (37%) died within 28 days after ICU admission and were classified as “nonsurvivors.” The minimum value for diastolic arterial blood pressure during the first 24 hours was independently associated with the 28-day mortality in the univariate and multivariate analyses model. This model performed better than the model using the Simplified Acute Physiology Score II, even when assessing the effect of inotrope and vasoactive treatments at 24, 48, and 72 hours.

CONCLUSIONS: In the first 24 hours of an ICU admission, the minimum diastolic arterial blood pressure was a hemodynamic variable that was independently associated with 28-day mortality in cardiogenic shock patients.

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