Theoretical optimization of pulmonary-to-systemic flow ratio after a bidirectional cavopulmonary anastomosis

1998 ◽  
Vol 274 (2) ◽  
pp. H694-H700 ◽  
Author(s):  
William P. Santamore ◽  
Ofer Barnea ◽  
Christopher J. Riordan ◽  
Mitchell P. Ross ◽  
Erle H. Austin
Keyword(s):  
Cardiac Output ◽  
Oxygen Consumption ◽  
Oxygen Saturation ◽  
Oxygen Delivery ◽  
Inferior Vena ◽  
Upper Body ◽  
Lower Body ◽  
Flow Ratio ◽  
Inferior Vena Caval ◽  
Cavopulmonary Anastomosis

A univentricle with parallel pulmonary and systemic circulations is inherently inefficient because mixing of pulmonary and systemic venous return occurs. Thus a cavopulmonary anastomosis is used as a staged palliative procedure to reduce volume overload in patients with cyanotic congenital heart disease. On the basis of oxygen uptake and consumption, an equation was derived that related cardiac output, pulmonary venous oxygen saturation, upper body oxygen consumption, and superior-to-inferior vena caval blood flow ratio (QSVC/QIVC) to oxygen delivery. The primary findings were as follows. 1) As QSVC/QIVCincreases, total body oxygen delivery and arterial and superior vena caval oxygen saturations increase. 2) As QSVC/QIVCincreases, lower body oxygen delivery and inferior vena caval oxygen saturation initially increase, then peak, and then decrease. 3) As the percentage of lower body oxygen consumption increases, oxygen delivery and saturation decrease. 4) A cavopulmonary anastomosis decreases the required cardiac output for a given oxygen delivery. Thus we concluded that a high systemic arterial oxygen saturation after cavopulmonary anastomosis requires a high percentage of upper body oxygen consumption and a high QSVC/QIVCand that the cavopulmonary anastomosis reduces the volume load on the single ventricle.

scholarly journals Retrograde Inferior Vena Caval Perfusion for Total Aortic Arch Replacement Surgery (RIVP-TARS): A Multicenter, Randomized, Controlled, Double-Blind Trial

2018 ◽  
Author(s):  
Jing Lin ◽  
Zhaoxia Tan ◽  
Xiaolin Hu ◽  
Hao Yao ◽  
Dafa Zhang ◽  
...  
Keyword(s):  
Inferior Vena ◽  
Moderate Hypothermia ◽  
Acute Type ◽  
Lower Body ◽  
Aortic Arch Replacement ◽  
Inferior Vena Caval ◽  
Type A Aortic Dissection ◽  
Replacement Surgery ◽  
Randomized Controlled ◽  
Total Aortic Arch Replacement

Abstract Background: During total aortic arch replacement surgery (TARS) for patients with acute type A aortic dissection, organs in the lower body such as the viscera and spinal cord are at risk of ischemia even when antegrade cerebral perfusion (ACP) is performed. Combining ACP with retrograde inferior vena caval perfusion (RIVP) during TARS may improve outcomes by providing the lower body with oxygenated blood. Methods: This is a multi-center, randomized, controlled trial of 500 patients scheduled for TARS. Patients were randomly allocated to a moderate hypothermia circulatory arrest (MHCA) group, who received selective ACP with moderate hypothermia during TARS; or to an RIVP group, who received the combination of RIVP and selective ACP under moderate hypothermia during TARS. The primary outcome was a composite of early mortality and major complications, including paraplegia, postoperative renal failure, severe liver dysfunction, postoperative prolonged intubation (>48 h), and gastrointestinal complications. Discussion: This study aims to assess whether RIVP combined with selective ACP leads to superior outcomes than selective ACP alone for patients undergoing TARS under moderate hypothermia. This study seeks to provide high-quality evidence for RIVP to be used in patients with acute type A aortic dissection undergoing TARS.

Abstract 17224: Volatile Anesthetic Agents Increase Cerebral to Systemic Blood Flow Ratio in Children Undergoing Cardiac Magnetic Resonance Imaging

Circulation ◽  
2018 ◽  
Vol 138 (Suppl_1) ◽  
Author(s):  
Amulya Buddhavarapu ◽  
Luisa Raga ◽  
Euleche Alanmanou ◽  
Prashob Porayette
Keyword(s):  
Magnetic Resonance Imaging ◽  
Blood Flow ◽  
Cardiac Output ◽  
Volatile Anesthetic ◽  
Flow Reversal ◽  
Lower Body ◽  
Flow Ratio ◽  
Resonance Imaging ◽  
Anesthetic Agents ◽  
Cerebral Vasodilation

Introduction: Cardiac magnetic resonance imaging (CMR) can reliably assess hemodynamics in children. Anesthetic agents may affect cerebral blood flow (CBF) and change the cerebral to systemic perfusion ratio. Hypothesis: Volatile anesthetic agents cause significant cerebral vasodilation resulting in descending aorta (DAo) flow reversal. Methods: Blood flow was measured in patients who underwent cine phase contract velocity mapping during CMR (1.5T, Philips Ingenia, Amsterdam, The Netherlands) with or without general anesthesia (GA) at our institution. Patients with a known cause for flow reversal in DAo (e.g. aortic insufficiency, aorto-pulmonary shunt/collaterals) or brain pathology were excluded. Flows in superior vena cava (SVC, surrogate for CBF), ascending aorta (AAo, measure of cardiac output), and DAo (measure of lower body perfusion) were analyzed. Measures of central tendency, standard deviation, correlation coefficient and Student’s t-test were calculated. Variables including anesthetic agents, body surface area (BSA), mechanical ventilator parameters and vital signs were assessed. Results: A total of 93 CMR scans were performed with GA (n=43, age 3 m to 15 y, BSA 0.29-2.4 m 2 ) or without GA (n=50, 2 w to 21 y, BSA 0.2-2.89 m 2 ). There was significant flow reversal in DAo (mean 7.62% +/- SD 7%) in GA group using volatile agents compared to non-GA patients (1.16% +/- 1.78%; p-value <0.001). SVC flow was higher in GA (1.66+/-1.02 ml/min/m 2 ) than non-GA patients (1.28+/-0.53 ml/min/m 2 ) but did not reach statistical significance (p=0.06). GA group had significantly higher SVC (cerebral blood) to AAo flow (cardiac output) ratio (0.53 +/- 0.13) than non-GA group (0.44 +/- 0.17; p=0.003), probably from increased CBF from cerebral vasodilation by volatile anesthetic agents. Patients with BSA >1.2 m 2 and GA (0.84 +/- 0.27) had a tendency to have higher SVC/DAo flow ratio compared to non-GA (0.69 +/- 0.3; p = 0.06) patients. There was a positive correlation between the end tidal CO 2 and SVC flow (r 0.486, R 2 0.236). Conclusions: The flow rates of SVC, AAo and DAo using CMR must be interpreted with caution in children, taking into account the effects of GA on the cerebral and lower body perfusion. This difference may be relevant in patients with congenital heart disease, especially with cavo-pulmonary and Fontan circulation.

Oxygen transport in the critically ill

2016 ◽  
Author(s):  
Stephan M. Jakob ◽  
Jukka Takala
Keyword(s):  
Oxygen Consumption ◽  
Oxygen Saturation ◽  
Oxygen Transport ◽  
Oxygen Delivery ◽  
Arterial Oxygen Saturation ◽  
Lactate Concentration ◽  
Mixed Venous Oxygen Saturation ◽  
Arterial Oxygen ◽  
Venous Oxygen Saturation ◽  
Mixed Venous

Adequate oxygen delivery is crucial for organ survival. The main determinants of oxygen delivery are cardiac output, haemoglobin concentration, and arterial oxygen saturation. The adequacy of oxygen delivery also depends on oxygen consumption, which may vary widely. Mixed venous oxygen saturation reflects the amount of oxygen not extracted by the tissues, and therefore provides useful information on the relationship between oxygen delivery and oxygen needs. If not in balance, tissue hypoxia may ensue and arterial lactate concentration increases. This occurs at higher oxygen delivery rates in acute compared with chronic diseases where metabolic adaptions often occur. Arterial and mixed venous oxygen saturation are related to each other. The influence of mixed venous saturation on arterial saturation increases with an increasing intrapulmonary shunt. This chapter discusses interactions between the components of oxygen transport and how they can be evaluated. Various methods for measuring tissue oxygenation and oxygen consumption are also presented, together with their limitations.

Oxygen delivery in lambs: cardiovascular and hematologic development

1979 ◽  
Vol 237 (6) ◽  
pp. H668-H675 ◽  
Author(s):  
G. Lister ◽  
T. K. Walter ◽  
H. T. Versmold ◽  
P. R. Dallman ◽  
A. M. Rudolph
Keyword(s):  
Cardiac Output ◽  
Oxygen Consumption ◽  
Oxygen Delivery ◽  
Venous Blood ◽  
Oxygen Affinity ◽  
Fetal Hemoglobin ◽  
Hemoglobin Concentration ◽  
Mixed Venous Blood ◽  
Hemoglobin Oxygen Affinity ◽  
Very High

After birth a decrease in hemoglobin concentration occurs while high metabolic demands are imposed on the infant by the extrauterine environment. Using the resting lamb as a model, we studied the mechanisms that are called into play during this period to maintain oxygen delivery. Measurements were made of oxygen consumption, arterial and mixed venous blood oxygen contents, cardiac output, hemoglobin concentration, percent fetal hemoglobin, 2,3-diphosphoglycerate, and hemoglobin oxygen affinity during the first two postnatal months. There was a rapid decrease in hemoglobin concentration after birth and concomitant decrease in hemoglobin oxygen affinity, changes similar to those described in humans. Cardiac output and oxygen consumption were both very high immediately after birth and declined in parallel, so that arteriovenous oxygen content difference was constant. Thus at rest cardiac output varies as a result of the changing need for oxygen. This relationship is independent of hemoglobin concentration or oxygen affinity within the normal range. If, however, oxygen demands were increased, oxygen delivery might be compromised by a limited ability to increase oxygen extraction during the immediate newborn period or when hemoglobin concentration is lowest.

Allocation of cardiac output to limb and kidney during hypotensive procedures

1963 ◽  
Vol 205 (3) ◽  
pp. 541-548 ◽  
Author(s):  
John C. McGiff
Keyword(s):  
Cardiac Output ◽  
Flow Pattern ◽  
Vessel Wall ◽  
Inferior Vena ◽  
Intrinsic Property ◽  
Blood Vessel Wall ◽  
Experimental Setting ◽  
Inferior Vena Caval ◽  
Renal Flow ◽  
Vascular Beds

Cardiac output, and renal and femoral venous outflows were measured simultaneously and continuously by rotameters during hemorrhage and inferior vena caval obstruction. Acute reductions in cardiac output resulted in an immediate increased femoral and renal fraction of the cardiac output, the femoral increasing more than the renal. Further augmentation of the femoral flow fraction with reduction of the renal flow fraction was accomplished by baroreceptor area denervation or guanethidine. Following guanethidine-induced reduction of sympathetic vasoconstrictor activity of the femoral bed, the femoral flow pattern was converted to a renal flow pattern. The partition of cardiac output during acute hypotensive procedures in this experimental setting was determined by differential vasoconstrictor activity, possibly by neurohumoral agents which selectively influence certain vascular beds, and by an intrinsic property of the blood vessel wall which determines in part its response to acute reduction in flow.

scholarly journals Retrograde inferior vena caval perfusion for total aortic arch replacement surgery (RIVP-TARS): study protocol for a multicenter, randomized, controlled trial

2019 ◽  
Author(s):  
Jing Lin ◽  
Zhaoxia Tan ◽  
Hao Yao ◽  
Xiaolin Hu ◽  
Dafa Zhang ◽  
...  
Keyword(s):  
Inferior Vena ◽  
Moderate Hypothermia ◽  
Acute Type ◽  
Lower Body ◽  
Aortic Arch Replacement ◽  
Inferior Vena Caval ◽  
Type A Aortic Dissection ◽  
Replacement Surgery ◽  
Randomized Controlled ◽  
Total Aortic Arch Replacement

Abstract Background: During total aortic arch replacement surgery (TARS) for patients with acute type A aortic dissection, organs in the lower body such as the viscera and spinal cord are at risk of ischemia even when antegrade cerebral perfusion (ACP) is performed. Combining ACP with retrograde inferior vena caval perfusion (RIVP) during TARS may improve outcomes by providing the lower body with oxygenated blood. Methods: This study is designed as a multicenter, computer-generated randomized, controlled, assessor-blind, parallel-group study with a superiority framework in patients scheduled for TARS.A total of 636 patients will be randomized on a 1:1 basis to a moderate hypothermia circulatory arrest (MHCA) group, who will receive selective ACP with moderate hypothermia during TARS; or to an RIVP group, who will receive the combination of RIVP and selective ACP under moderate hypothermia during TARS. The primary outcome will be a composite of early mortality and major complications, including paraplegia, postoperative renal failure, severe liver dysfunction and gastrointestinal complications. All patients will be analyzed according to the intention- to-treat protocol. Discussion: This study aims to assess whether RIVP combined with ACP leads to superior outcomes than ACP alone for patients undergoing TARS under moderate hypothermia. This study seeks to provide high-quality evidence for RIVP to be used in patients with acute type A aortic dissection undergoing TARS. Trial registration. Clinicaltrials.gov, NCT03607786. Registered on 30 July 2018.

Balancing pulmonary and systemic arterial flows in parallel circulations: the value of monitoring system venous oxygen saturations

1997 ◽  
Vol 7 (1) ◽  
pp. 74-79 ◽  
Author(s):  
Christopher J. Riordan ◽  
Flemming Randsbaek ◽  
John H. Storey ◽  
William D. Montgomery ◽  
William P. Santamore ◽  
...  
Keyword(s):  
Oxygen Saturation ◽  
Congenital Heart Defects ◽  
Oxygen Delivery ◽  
Congenital Heart ◽  
Heart Defects ◽  
Arterial Oxygen Saturation ◽  
Limited Range ◽  
Arterial Oxygen ◽  
Flow Ratio ◽  
Venous Oxygen Saturation

AbstractAccurate bedside assessment of the ratio of pulmonary to systemic flow (Qp/Qs ratio, referred to as “the flow ratio” or “the ratio”) plays an important role in the management of many congenital heart defects, especially the complexes unified by univentricular atrioventricular connections. Arterial oxygen saturation can be a misleading measure of the ratio, and may not reflect derangements until they are quite large. Theoretical analysis suggests that systemic venous oxygenation may be a better indicator of the ratio. To examine this, we created a widely patent atrial septal defect in neonatal piglets (weight =4–6.5 kg, n=6). Snares aruond the aorta and pulmonary trunk were adjusted to alter the flow ratio from 0.1 to 6.5. Venous oxygen saturations, measured in the mid-inferior caval vein, were at a maximum at a ratio about 1, and declined rapidly with increases or decreases in the ratio beyond a limited range. The venous oxygen saturation was found to vary much more than arterial oxygen saturation, with arterial oxygen saturation only falling when the ratio dropped below 0.5. Oxygen delivery (Oxygen Content x Cardiacoutput) was found to parallel closely systemic venous oxygen saturation, and was at a maximum at the same ratio that produced a maximum value of systemic venous oxygen saturation. The study suggests that systemic venous oxygen saturation provides a better estimate than does systemic arterial oxygen saturationof the flow ratio and oxygen delivery. Interventions that maximize systemic venous oxygen saturation should maximize oxygen delivery, and determination of systemic venous oxygen saturation should be a helpful addition in managing children with a number of congenital heart defects.

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