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Bachmann KF, Haenggi M, Jakob SM, Takala J, Gattinoni L, Berger D. Comment on: "A novel 'shunt fraction' method to derive native cardiac output during liberation from central VA ECMO" by Lim, HS. ESC Heart Fail 2024; 11:2464-2466. [PMID: 38605504 PMCID: PMC11287345 DOI: 10.1002/ehf2.14804] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2024] [Revised: 03/18/2024] [Accepted: 03/22/2024] [Indexed: 04/13/2024] Open
Affiliation(s)
- Kaspar F Bachmann
- Department of Intensive Care Medicine, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
| | - Matthias Haenggi
- Department of Intensive Care Medicine, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
| | | | | | - Luciano Gattinoni
- Department of Anesthesiology, Medical University of Göttingen, University Medical Center Göttingen, Göttingen, Germany
| | - David Berger
- Department of Intensive Care Medicine, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
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Bachmann KF, Moller PW, Hunziker L, Maggiorini M, Berger D. Mechanisms maintaining right ventricular contractility-to-pulmonary arterial elastance ratio in VA ECMO: a retrospective animal data analysis of RV-PA coupling. J Intensive Care 2024; 12:19. [PMID: 38734616 PMCID: PMC11088130 DOI: 10.1186/s40560-024-00730-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2024] [Accepted: 04/14/2024] [Indexed: 05/13/2024] Open
Abstract
BACKGROUND To optimize right ventricular-pulmonary coupling during veno-arterial (VA) ECMO weaning, inotropes, vasopressors and/or vasodilators are used to change right ventricular (RV) function (contractility) and pulmonary artery (PA) elastance (afterload). RV-PA coupling is the ratio between right ventricular contractility and pulmonary vascular elastance and as such, is a measure of optimized crosstalk between ventricle and vasculature. Little is known about the physiology of RV-PA coupling during VA ECMO. This study describes adaptive mechanisms for maintaining RV-PA coupling resulting from changing pre- and afterload conditions in VA ECMO. METHODS In 13 pigs, extracorporeal flow was reduced from 4 to 1 L/min at baseline and increased afterload (pulmonary embolism and hypoxic vasoconstriction). Pressure and flow signals estimated right ventricular end-systolic elastance and pulmonary arterial elastance. Linear mixed-effect models estimated the association between conditions and elastance. RESULTS At no extracorporeal flow, end-systolic elastance increased from 0.83 [0.66 to 1.00] mmHg/mL at baseline by 0.44 [0.29 to 0.59] mmHg/mL with pulmonary embolism and by 1.36 [1.21 to 1.51] mmHg/mL with hypoxic pulmonary vasoconstriction (p < 0.001). Pulmonary arterial elastance increased from 0.39 [0.30 to 0.49] mmHg/mL at baseline by 0.36 [0.27 to 0.44] mmHg/mL with pulmonary embolism and by 0.75 [0.67 to 0.84] mmHg/mL with hypoxic pulmonary vasoconstriction (p < 0.001). Coupling remained unchanged (2.1 [1.8 to 2.3] mmHg/mL at baseline; - 0.1 [- 0.3 to 0.1] mmHg/mL increase with pulmonary embolism; - 0.2 [- 0.4 to 0.0] mmHg/mL with hypoxic pulmonary vasoconstriction, p > 0.05). Extracorporeal flow did not change coupling (0.0 [- 0.0 to 0.1] per change of 1 L/min, p > 0.05). End-diastolic volume increased with decreasing extracorporeal flow (7.2 [6.6 to 7.8] ml change per 1 L/min, p < 0.001). CONCLUSIONS The right ventricle dilates with increased preload and increases its contractility in response to afterload changes to maintain ventricular-arterial coupling during VA extracorporeal membrane oxygenation.
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Affiliation(s)
- Kaspar F Bachmann
- Department of Intensive Care Medicine, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland.
| | - Per Werner Moller
- Department of Anesthesia, SV Hospital Group, Institute of Clinical Sciences at the Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Lukas Hunziker
- Department of Cardiology, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
| | - Marco Maggiorini
- Medical Intensive Care Unit, University Hospital Zürich, University of Zürich, Zurich, Switzerland
| | - David Berger
- Department of Intensive Care Medicine, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
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Berger D, Stanger EJ, Jenni H, Fried PD, Bachmann KF. Modified Thermodilution for Simultaneous Cardiac Output and Recirculation Assessment in Veno-venous Extracorporeal Membrane Oxygenation: A Prospective Diagnostic Accuracy Study. Anesthesiology 2024; 140:1002-1015. [PMID: 38157435 DOI: 10.1097/aln.0000000000004895] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2024]
Abstract
BACKGROUND Thermodilution is unreliable in veno-venous extracorporeal membrane oxygenation (VV-ECMO). Systemic oxygenation depends on recirculation fractions and ratios of extracorporeal membrane oxygenation (ECMO) flow to cardiac output. In a prospective in vitro simulation, this study assessed the diagnostic accuracy of a modified thermodilution technique for recirculation and cardiac output. The hypothesis was that this method provided clinically acceptable precision and accuracy for cardiac output and recirculation. METHODS Two ECMO circuits ran in parallel: one representing a VV-ECMO and the second representing native heart, lung, and circulation. Both circuits shared the right atrium. Extra limbs for recirculation and pulmonary shunt were added. This study simulated ECMO flows from 1 to 2.5 l/min and cardiac outputs from 2.5 to 3.5 l/min with recirculation fractions (0 to 80%) and pulmonary shunts. Thermistors in both ECMO limbs and the pulmonary artery measured the temperature changes induced by cold bolus injections into the arterial ECMO limb. Recirculation fractions were calculated from the ratio of the areas under the temperature curve (AUCs) in the ECMO limbs and from partitioning of the bolus volume (flow based). With known partitioning of bolus volumes between ECMO and pulmonary artery, cardiac output was calculated. High-precision ultrasonic flow probes served as reference for Bland-Altman plots and linear mixed-effect models. RESULTS Accuracy and precision for both the recirculation fraction based on AUC (bias, -5.4%; limits of agreement, -18.6 to 7.9%) and flow based (bias, -5.9%; limits of agreement, -18.8 to 7.0%) are clinically acceptable. Calculated cardiac output for all recirculation fractions was accurate but imprecise (RecirculationAUC: bias 0.56 l/min; limits of agreement, -2.27 to 3.4 l/min; and RecirculationFLOW: bias 0.48 l/min; limits of agreement, -2.22 to 3.19 l/min). Recirculation fraction increased bias and decreased precision. CONCLUSIONS Adapted thermodilution for VV-ECMO allows simultaneous measurement of recirculation fraction and cardiac output and may help optimize patient management with severe respiratory failure. EDITOR’S PERSPECTIVE
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Affiliation(s)
- David Berger
- Department of Intensive Care Medicine, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
| | - Elia J Stanger
- Department of Intensive Care Medicine, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
| | - Hansjörg Jenni
- Department of Cardiovascular Surgery, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
| | - Philipp D Fried
- Department of Intensive Care Medicine, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
| | - Kaspar F Bachmann
- Department of Intensive Care Medicine, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
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Bachmann KF, Berger D, Moller PW. Interactions between extracorporeal support and the cardiopulmonary system. Front Physiol 2023; 14:1231016. [PMID: 37772062 PMCID: PMC10523013 DOI: 10.3389/fphys.2023.1231016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2023] [Accepted: 08/29/2023] [Indexed: 09/30/2023] Open
Abstract
This review describes the intricate physiological interactions involved in the application of extracorporeal therapy, with specific focus on cardiopulmonary relationships. Extracorporeal therapy significantly influences cardiovascular and pulmonary physiology, highlighting the necessity for clinicians to understand these interactions for improved patient care. Veno-arterial extracorporeal membrane oxygenation (veno-arterial ECMO) unloads the right ventricle and increases left ventricular (LV) afterload, potentially exacerbating LV failure and pulmonary edema. Veno-venous (VV) ECMO presents different challenges, where optimal device and ventilator settings remain unknown. Influences on right heart function and native gas exchange as well as end-expiratory lung volumes are important concepts that should be incorporated into daily practice. Future studies should not be limited to large clinical trials focused on mortality but rather address physiological questions to advance the understanding of extracorporeal therapies. This includes exploring optimal device and ventilator settings in VV ECMO, standardizing cardiopulmonary function monitoring strategies, and developing better strategies for device management throughout their use. In this regard, small human or animal studies and computational physiological modeling may contribute valuable insights into optimizing the management of extracorporeal therapies.
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Affiliation(s)
- Kaspar F. Bachmann
- Department of Intensive Care Medicine, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
- Department of Anaesthesiology and Intensive Care, University of Tartu, Tartu, Estonia
| | - David Berger
- Department of Intensive Care Medicine, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
| | - Per Werner Moller
- Department of Anaesthesia, SV Hospital Group, Institute of Clinical Sciences at the Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
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Berger D, Werner Moller P, Bachmann KF. Cardiopulmonary interactions-which monitoring tools to use? Front Physiol 2023; 14:1234915. [PMID: 37621761 PMCID: PMC10445648 DOI: 10.3389/fphys.2023.1234915] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2023] [Accepted: 07/18/2023] [Indexed: 08/26/2023] Open
Abstract
Heart-lung interactions occur due to the mechanical influence of intrathoracic pressure and lung volume changes on cardiac and circulatory function. These interactions manifest as respiratory fluctuations in venous, pulmonary, and arterial pressures, potentially affecting stroke volume. In the context of functional hemodynamic monitoring, pulse or stroke volume variation (pulse pressure variation or stroke volume variability) are commonly employed to assess volume or preload responsiveness. However, correct interpretation of these parameters requires a comprehensive understanding of the physiological factors that determine pulse pressure and stroke volume. These factors include pleural pressure, venous return, pulmonary vessel function, lung mechanics, gas exchange, and specific cardiac factors. A comprehensive knowledge of heart-lung physiology is vital to avoid clinical misjudgments, particularly in cases of right ventricular (RV) failure or diastolic dysfunction. Therefore, when selecting monitoring devices or technologies, these factors must be considered. Invasive arterial pressure measurements of variations in breath-to-breath pressure swings are commonly used to monitor heart-lung interactions. Echocardiography or pulmonary artery catheters are valuable tools for differentiating preload responsiveness from right ventricular failure, while changes in diastolic function should be assessed alongside alterations in airway or pleural pressure, which can be approximated by esophageal pressure. In complex clinical scenarios like ARDS, combined forms of shock or right heart failure, additional information on gas exchange and pulmonary mechanics aids in the interpretation of heart-lung interactions. This review aims to describe monitoring techniques that provide clinicians with an integrative understanding of a patient's condition, enabling accurate assessment and patient care.
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Affiliation(s)
- David Berger
- Department of Intensive Care Medicine, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
| | - Per Werner Moller
- Department of Anaesthesia, SV Hospital Group, Institute of Clinical Sciences at the Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Kaspar F. Bachmann
- Department of Intensive Care Medicine, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
- Department of Anaesthesiology and Intensive Care, University of Tartu, Tartu, Estonia
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Stanger EJ, Berger DC, Jenni H, Bachmann KF. Behaviour and stability of thermodilution signals in a closed extracorporeal circuit: a bench study. J Clin Monit Comput 2023:10.1007/s10877-023-01018-0. [PMID: 37166694 PMCID: PMC10371883 DOI: 10.1007/s10877-023-01018-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Accepted: 04/14/2023] [Indexed: 05/12/2023]
Abstract
Thermodilution is the gold standard for cardiac output measurement in critically ill patients. Its application in extracorporeal therapy is limited, as a portion of the thermal indicator is drawn into the extracorporeal circuit. The behaviour of thermodilution signals in extracorporeal circuits is unknown. We investigated thermodilution curves within a closed-circuit and assessed the impact of injection volume, flow and distance on the behaviour of the thermodilution signals and catheter constants. We injected 3, 5, 7 and 10 ml of thermal indicator into a heated closed circuit. Thermistors at distances of 40, 60, 80, and 100 cm from the injection port recorded the thermodilution signals (at flow settings of 0.5, 1, 1.5, and 2 L/min). Area under the curve (AUC), rise time, exponential decay and catheter constants were analysed. Linear mixed-effects models were used to evaluate the impact of circuit flow, distance and injection volume. Catheter positioning did not influence AUC (78 injections). Catheter constants were independent of flow, injection volume or distance to the injection port. The distance to the injection port increased peak temperature and rise time and decreased exponential time constant significantly. The distance to the injection port did not influence catheter constants, but the properties of the thermodilution signal itself. This may influence measurements that depend on the exponential decay of the thermodilution signal such as right ventricular ejection fraction.
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Affiliation(s)
- Elia J Stanger
- Department of Intensive Care Medicine, Inselspital, Bern University Hospital, University of Bern, Freiburgstrasse 3000, Bern, Switzerland
| | - David C Berger
- Department of Intensive Care Medicine, Inselspital, Bern University Hospital, University of Bern, Freiburgstrasse 3000, Bern, Switzerland
| | - Hansjörg Jenni
- Department of Cardiovascular Surgery, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
| | - Kaspar F Bachmann
- Department of Intensive Care Medicine, Inselspital, Bern University Hospital, University of Bern, Freiburgstrasse 3000, Bern, Switzerland.
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Berger DC, Zwicker L, Nettelbeck K, Casoni D, Heinisch PP, Jenni H, Haenggi M, Gattinoni L, Bachmann KF. Integral assessment of gas exchange during veno-arterial ECMO: accuracy and precision of a modified Fick principle in a porcine model. Am J Physiol Lung Cell Mol Physiol 2023; 324:L102-L113. [PMID: 36511508 PMCID: PMC9870575 DOI: 10.1152/ajplung.00045.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Assessment of native cardiac output during extracorporeal circulation is challenging. We assessed a modified Fick principle under conditions such as dead space and shunt in 13 anesthetized swine undergoing centrally cannulated veno-arterial extracorporeal membrane oxygenation (V-A ECMO, 308 measurement periods) therapy. We assumed that the ratio of carbon dioxide elimination (V̇co2) or oxygen uptake (V̇o2) between the membrane and native lung corresponds to the ratio of respective blood flows. Unequal ventilation/perfusion (V̇/Q̇) ratios were corrected towards unity. Pulmonary blood flow was calculated and compared to an ultrasonic flow probe on the pulmonary artery with a bias of 99 mL/min (limits of agreement -542 to 741 mL/min) with blood content V̇o2 and no-shunt, no-dead space conditions, which showed good trending ability (least significant change from 82 to 129 mL). Shunt conditions led to underestimation of native pulmonary blood flow (bias -395, limits of agreement -1,290 to 500 mL/min). Bias and trending further depended on the gas (O2, CO2) and measurement approach (blood content vs. gas phase). Measurements in the gas phase increased the bias (253 [LoA -1,357 to 1,863 mL/min] for expired V̇o2 bias 482 [LoA -760 to 1,724 mL/min] for expired V̇co2) and could be improved by correction of V̇/Q̇ inequalities. Our results show that common assumptions of the Fick principle in two competing circulations give results with adequate accuracy and may offer a clinically applicable tool. Precision depends on specific conditions. This highlights the complexity of gas exchange in membrane lungs and may further deepen the understanding of V-A ECMO.
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Affiliation(s)
- David C. Berger
- 1Department of Intensive Care Medicine, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
| | - Lena Zwicker
- 1Department of Intensive Care Medicine, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
| | - Kay Nettelbeck
- 1Department of Intensive Care Medicine, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland,2Experimental Surgery Facility (ESF), Department for BioMedical
Research, Faculty of Medicine, University of Bern, Bern, Switzerland
| | - Daniela Casoni
- 2Experimental Surgery Facility (ESF), Department for BioMedical
Research, Faculty of Medicine, University of Bern, Bern, Switzerland
| | - Paul Phillipp Heinisch
- 3Department of Congenital and Pediatric Heart Surgery, German Heart Center Munich, Technische Universität München, Munich, Germany
| | - Hansjörg Jenni
- 3Department of Congenital and Pediatric Heart Surgery, German Heart Center Munich, Technische Universität München, Munich, Germany
| | - Matthias Haenggi
- 1Department of Intensive Care Medicine, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
| | - Luciano Gattinoni
- 5Department of Anesthesiology, Medical University of Göttingen, University Medical Center Göttingen, Göttingen, Germany
| | - Kaspar F. Bachmann
- 1Department of Intensive Care Medicine, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland,4Department of Anesthesiology & Pain Medicine, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
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Bachmann KF, Vasireddy R, Heinisch PP, Jenni H, Vogt A, Berger D. Estimating cardiac output based on gas exchange during veno-arterial extracorporeal membrane oxygenation in a simulation study using paediatric oxygenators. Sci Rep 2021; 11:11528. [PMID: 34075067 PMCID: PMC8169686 DOI: 10.1038/s41598-021-90747-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2020] [Accepted: 05/17/2021] [Indexed: 11/29/2022] Open
Abstract
Veno-arterial extracorporeal membrane oxygenation (VA-ECMO) therapy is a rescue strategy for severe cardiopulmonary failure. The estimation of cardiac output during VA-ECMO is challenging. A lung circuit (\documentclass[12pt]{minimal}
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\begin{document}$$\mathop {\text{V}}\limits^{.}$$\end{document}V.O2) simulated the setting of VA-ECMO with varying ventilation/perfusion (\documentclass[12pt]{minimal}
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\begin{document}$$\mathop {\text{V}}\limits^{.}$$\end{document}V./\documentclass[12pt]{minimal}
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\begin{document}$${\dot{\text{Q}}}$$\end{document}Q˙) ratios and shunt. A metabolic chamber with a CO2/N2 blend simulated \documentclass[12pt]{minimal}
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\begin{document}$$\mathop {\text{V}}\limits^{.}$$\end{document}V.O2. \documentclass[12pt]{minimal}
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\begin{document}$${\dot{\text{Q}}}$$\end{document}Q˙Lung was estimated with a modified Fick principle: \documentclass[12pt]{minimal}
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\begin{document}$${\dot{\text{Q}}}$$\end{document}Q˙Lung = \documentclass[12pt]{minimal}
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\begin{document}$$\mathop {\text{V}}\limits^{.}$$\end{document}V. CO2 or \documentclass[12pt]{minimal}
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\begin{document}$$\mathop {\text{V}}\limits^{.}$$\end{document}V.O2Lung)/(\documentclass[12pt]{minimal}
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\begin{document}$$\mathop {\text{V}}\limits^{.}$$\end{document}V.CO2 or \documentclass[12pt]{minimal}
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\begin{document}$$\mathop {\text{V}}\limits^{.}$$\end{document}V.O2ECMO). A normalization procedure corrected \documentclass[12pt]{minimal}
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\begin{document}$$\mathop {\text{V}}\limits^{.}$$\end{document}V.CO2 values for a \documentclass[12pt]{minimal}
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\begin{document}$${\dot{\text{Q}}}$$\end{document}Q˙ of 1. Method agreement was evaluated by Bland–Altman analysis. Calculated \documentclass[12pt]{minimal}
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\begin{document}$${\dot{\text{Q}}}$$\end{document}Q˙Lung using gaseous \documentclass[12pt]{minimal}
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\begin{document}$$\mathop {\text{V}}\limits^{.}$$\end{document}V.O2 correlated well with measured \documentclass[12pt]{minimal}
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\begin{document}$${\dot{\text{Q}}}$$\end{document}Q˙Lung with a bias of 103 ml/min [− 268 to 185] ml/min; Limits of Agreement: − 306 ml/min [− 241 to − 877 ml/min] to 512 ml/min [447 to 610 ml/min], r2 0.85 [0.79–0.88]). Blood measurements of \documentclass[12pt]{minimal}
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\begin{document}$$\mathop {\text{V}}\limits^{.}$$\end{document}V.CO2 showed an increased bias (− 260 ml/min [− 1503 to 982] ml/min), clinically not applicable. Shunt and \documentclass[12pt]{minimal}
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\begin{document}$${\dot{\text{Q}}}$$\end{document}Q˙ mismatch decreased the agreement of methods significantly. This in-vitro simulation shows that \documentclass[12pt]{minimal}
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\begin{document}$$\mathop {\text{V}}\limits^{.}$$\end{document}V.O2 in steady-state conditions allow for clinically applicable calculations of \documentclass[12pt]{minimal}
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\begin{document}$${\dot{\text{Q}}}$$\end{document}Q˙Lung during VA-ECMO therapy.
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Affiliation(s)
- Kaspar Felix Bachmann
- Department of Anaesthesiology and Pain Medicine, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland. .,Department of Intensive Care Medicine, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland.
| | - Rakesh Vasireddy
- Department of Anaesthesiology and Pain Medicine, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
| | - Paul Philipp Heinisch
- Department of Cardiac and Vascular Surgery, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland.,Department of Congenital and Pediatric Heart Surgery, German Heart Center Munich, Technische Universität München, Munich, Germany
| | - Hansjörg Jenni
- Department of Cardiac and Vascular Surgery, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
| | - Andreas Vogt
- Department of Anaesthesiology and Pain Medicine, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
| | - David Berger
- Department of Intensive Care Medicine, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
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Valenti E, Moller PW, Takala J, Berger D. Collapsibility of caval vessels and right ventricular afterload: decoupling of stroke volume variation from preload during mechanical ventilation. J Appl Physiol (1985) 2021; 130:1562-1572. [PMID: 33734829 DOI: 10.1152/japplphysiol.01039.2020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Collapsibility of caval vessels and stroke volume and pulse pressure variations (SVV, PPV) are used as indicators of volume responsiveness. Their behavior under increasing airway pressures and changing right ventricular afterload is incompletely understood. If the phenomena of SVV and PPV augmentation are manifestations of decreasing preload, they should be accompanied by decreasing transmural right atrial pressures. Eight healthy pigs equipped with ultrasonic flow probes on the pulmonary artery were exposed to positive end-expiratory pressure of 5 and 10 cmH2O and three volume states (Euvolemia, defined as SVV < 10%, Bleeding, and Retransfusion). SVV and PPV were calculated for the right and PPV for the left side of the circulation at increasing inspiratory airway pressures (15, 20, and 25 cmH2O). Right ventricular afterload was assessed by surrogate flow profile parameters. Transmural pressures in the right atrium and the inferior and superior caval vessels (IVC and SVC) were determined. Increasing airway pressure led to increases in ultrasonic surrogate parameters of right ventricular afterload, increasing transmural pressures in the right atrium and SVC, and a drop in transmural IVC pressure. SVV and PPV increased with increasing airway pressure, despite the increase in right atrial transmural pressure. Right ventricular stroke volume variation correlated with indicators of right ventricular afterload. This behavior was observed in both PEEP levels and all volume states. Stroke volume variation may reflect changes in right ventricular afterload rather than changes in preload.NEW & NOTEWORTHY Stroke volume variation and pulse pressure variation are used as indicators of preload or volume responsiveness of the heart. Our study shows that these variations are influenced by changes in right ventricular afterload and may therefore reflect right ventricular failure rather than pure volume responsiveness. A zone of collapse detaches the superior vena cava and its diameter variation from the right atrium.
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Affiliation(s)
- Elisa Valenti
- Department of Intensive Care Medicine, Inselspital University Hospital, University of Bern, Bern, Switzerland.,Intensive Care Unit and Department of Intensive Care, Ospedale Regionale di Lugano, Lugano, Switzerland
| | - Per W Moller
- Department of Anesthesiology and Intensive Care Medicine, Institute of Clinical Sciences at the Sahlgrenska Academy, University of Gothenburg, SV Hospital Group, Alingsas, Sweden
| | - Jukka Takala
- Department of Intensive Care Medicine, Inselspital University Hospital, University of Bern, Bern, Switzerland
| | - David Berger
- Department of Intensive Care Medicine, Inselspital University Hospital, University of Bern, Bern, Switzerland
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Venoarterial Extracorporeal Membrane Oxygenation. Anesthesiology 2020; 133:708-710. [PMID: 32796200 DOI: 10.1097/aln.0000000000003487] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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11
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Mourad M, Eliet J, Zeroual N, Saour M, Sentenac P, Manna F, Molinari N, Gandet T, Colson PH, Gaudard P. Pulse pressure and end-tidal carbon dioxide for monitoring low native cardiac output during veno-arterial ECLS: a prospective observational study. CRITICAL CARE : THE OFFICIAL JOURNAL OF THE CRITICAL CARE FORUM 2020; 24:569. [PMID: 32962727 PMCID: PMC7507590 DOI: 10.1186/s13054-020-03280-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/19/2020] [Accepted: 09/10/2020] [Indexed: 11/18/2022]
Abstract
Background Veno-arterial extracorporeal life support (VA-ECLS) results in cardiopulmonary shunting with reduced native cardiac output (NCO). Low NCO occurrence is common and associated with risk of thromboembolic and pulmonary complications. Practical tools for monitoring NCO during VA-ECLS would therefore be valuable. Pulse pressure (PP) and end-tidal carbon dioxide (EtCO2) are known to be related to cardiac output. We have designed a study to test whether PP and EtCO2 were efficient for the monitoring of NCO during VA-ECLS. Methods In this prospective single-center observational study, patients who underwent a VA-ECLS for cardiogenic shock from January 2016 to October 2017 were included, provided low NCO was suspected by a PP < 20 mmHg. NCO was measured with pulmonary artery catheter or echocardiography and compared to PP and EtCO2. The ability of PP and EtCO2 to predict NCO < 1 L/min was evaluated with receiver operating characteristics (ROC) curves. Results Among the 106 patients treated with VA-ECLS for cardiogenic shock during the study period, 26 were studied, allowing the collection of 196 study points. PP and EtCO2 relationships with NCO were nonlinear and showed strong correlations for NCO < 2 L/min (r = 0.69 and r = 0.78 respectively). A PP < 15 mmHg and EtCO2 < 14 mmHg had good predictive values for detecting NCO < 1 L/min (area under ROC curve 0.93 [95% CI 0.89–0.96] and 0.97 [95% CI 0.94–0.99] respectively, p = 0.058). Conclusions PP and EtCO2 may offer an accurate real-time monitoring of low NCO events during VA-ECLS support. Further studies are needed to show if their utilization may help to implement therapeutic strategies in order to prevent thromboembolic and respiratory complications associated with VA-ECLS, and to improve patients’ prognosis. Trial registration NCT03323268, July 12, 2016
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Affiliation(s)
- Marc Mourad
- Department of Anesthesiology and Critical Care Medicine, Arnaud de Villeneuve Hospital, CHU Montpellier, Univ Montpellier, Montpellier, France.
| | - Jacob Eliet
- Department of Anesthesiology and Critical Care Medicine, Arnaud de Villeneuve Hospital, CHU Montpellier, Univ Montpellier, Montpellier, France
| | - Norddine Zeroual
- Department of Anesthesiology and Critical Care Medicine, Arnaud de Villeneuve Hospital, CHU Montpellier, Univ Montpellier, Montpellier, France
| | - Marine Saour
- Department of Anesthesiology and Critical Care Medicine, Arnaud de Villeneuve Hospital, CHU Montpellier, Univ Montpellier, Montpellier, France
| | - Pierre Sentenac
- Department of Anesthesiology and Critical Care Medicine, Arnaud de Villeneuve Hospital, CHU Montpellier, Univ Montpellier, Montpellier, France
| | - Federico Manna
- Epidemiology and Clinical Research Department, CHU Montpellier, Univ Montpellier, Montpellier, France
| | - Nicolas Molinari
- Epidemiology and Clinical Research Department, CHU Montpellier, Univ Montpellier, Montpellier, France
| | - Thomas Gandet
- Department of Cardiac Surgery, CHU Montpellier, Univ Montpellier, Montpellier, France
| | - Pascal H Colson
- Department of Anesthesiology and Critical Care Medicine, Arnaud de Villeneuve Hospital, CHU Montpellier, Univ Montpellier, Montpellier, France.,Univ Montpellier, CNRS, INSERM, Institut de Génomique Fonctionnelle, Montpellier, France
| | - Philippe Gaudard
- Department of Anesthesiology and Critical Care Medicine, Arnaud de Villeneuve Hospital, CHU Montpellier, Univ Montpellier, Montpellier, France.,Univ Montpellier, CNRS, INSERM, PhyMedExp, Montpellier, France
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