MATHEMATICAL MODELING OF STROKE VOLUME FROM THE PERIPHERAL BLOOD FLOW FOR NON INVASIVE PLETHYSMOGRAPHIC MEASUREMENT OF CARDIAC OUTPUT AND ITS VALIDATION

2017 ◽  
Vol 29 (06) ◽  
pp. 1750041
Author(s):  
Pranali Choudhari ◽  
M. S. Panse
Keyword(s):  
Blood Flow ◽  
Cardiac Output ◽  
Stroke Volume ◽  
Peripheral Blood ◽  
Clinical Medicine ◽  
Patient Specific ◽  
Peripheral Blood Flow ◽  
Lung Water ◽  
Non Invasive ◽  
Multiple Variable

The ability to accurately measure Cardiac Output (CO) is important in clinical medicine as it helps in improving diagnosis of abnormalities and appropriate disease management. In spite of being an important vital parameter, it is still missing from the screens of the bedside monitors employed today. This could be due to the invasiveness of the method or the discomfort in the measurement. Invasive methods are most accurate but can be best suited for the intensive care units (ICUs) and surgeries, but for bedside measurement these methods add an unnecessary risk to the life of the patient. The existing non-invasive method employed for CO measurement is the thoracic bioimpedance method, which is risky for patients with cardiovascular diseases and inaccurate for patients with extra vascular lung water. This paper presents a novel method of CO measurement from the peripheral blood flow, which fairly overcomes the disadvantages of the existing method. The impedance pulse has been acquired across the wrist, instead of the thorax. A new stroke volume equation has been modeled by carrying out the finite element simulation of the blood flow and multiple variable regression to incorporate the patient specific factors. The stroke volume thus obtained has been validated for 57 subjects.

Cardiac Output Changes in Newborns With Hyperbilirubinemia Treated With Phototherapy

PEDIATRICS ◽  
1985 ◽  
Vol 76 (6) ◽  
pp. 918-921
Author(s):  
Frans J. Walther ◽  
Paul Y. K. Wu ◽  
Bijan Siassi
Keyword(s):  
Blood Flow ◽  
Cardiac Output ◽  
Stroke Volume ◽  
Skin Blood Flow ◽  
Peripheral Blood ◽  
Cardiovascular Effects ◽  
Tissue Perfusion ◽  
Peripheral Blood Flow ◽  
Limb Blood Flow ◽  
Term Infants

Phototherapy is known to increase peripheral blood flow in neonates, but information on the associated cardiovascular effects is not available. Using pulsed Doppler echocardiography we evaluated cardiac output and stroke volume in 12 preterm and 13 term neonates during and after phototherapy. We concomitantly measured arterial limb blood flow by strain gauge plethysmography and skin blood flow by photoplethysmography. Cardiac output decreased by 6% due to reduced stroke volume during phototherapy, whereas total limb blood flow and skin blood flow increased by 38% and 41%, respectively. Peripheral blood flow increments tended to be higher in the preterm than in the term infants. The reduced stroke volume during phototherapy may be an expression of reduced activity of the newborn during phototherapy. For healthy neonates the reduction in cardiac output is minimal, but for sick infants with reduced cardiac output, this reduction may further aggravate the decrease in tissue perfusion.

Improved cardiac output and peripheral blood flow after correcting neonatal hyperviscosity

1985 ◽  
Vol 110 (3) ◽  
pp. 707
Author(s):  
Sydney Swetnam ◽  
Dale Alverson ◽  
Steven M. Yabek ◽  
Pam Angelus ◽  
Connie Bakstrom ◽  
...  
Keyword(s):  
Blood Flow ◽  
Cardiac Output ◽  
Peripheral Blood ◽  
Peripheral Blood Flow

The underwater environment: cardiopulmonary, thermal, and energetic demands

2009 ◽  
Vol 106 (1) ◽  
pp. 276-283 ◽  
Author(s):  
D. R. Pendergast ◽  
C. E. G. Lundgren
Keyword(s):  
Blood Pressure ◽  
Blood Flow ◽  
Cardiac Output ◽  
Stroke Volume ◽  
Time Dependent ◽  
Breath Holding ◽  
Peripheral Blood Flow ◽  
Short Term ◽  
Underwater Environment ◽  
Maximal Cardiac Output

Water covers over 75% of the earth, has a wide variety of depths and temperatures, and holds a great deal of the earth's resources. The challenges of the underwater environment are underappreciated and more short term compared with those of space travel. Immersion in water alters the cardio-endocrine-renal axis as there is an immediate translocation of blood to the heart and a slower autotransfusion of fluid from the cells to the vascular compartment. Both of these changes result in an increase in stroke volume and cardiac output. The stretch of the atrium and transient increase in blood pressure cause both endocrine and autonomic changes, which in the short term return plasma volume to control levels and decrease total peripheral resistance and thus regulate blood pressure. The reduced sympathetic nerve activity has effects on arteriolar resistance, resulting in hyperperfusion of some tissues, which for specific tissues is time dependent. The increased central blood volume results in increased pulmonary artery pressure and a decline in vital capacity. The effect of increased hydrostatic pressure due to the depth of submersion does not affect stroke volume; however, a bradycardia results in decreased cardiac output, which is further reduced during breath holding. Hydrostatic compression, however, leads to elastic loading of the chest wall and negative pressure breathing. The depth-dependent increased work of breathing leads to augmented respiratory muscle blood flow. The blood flow is increased to all lung zones with some improvement in the ventilation-perfusion relationship. The cardiac-renal responses are time dependent; however, the increased stroke volume and cardiac output are, during head-out immersion, sustained for at least hours. Changes in water temperature do not affect resting cardiac output; however, maximal cardiac output is reduced, as is peripheral blood flow, which results in reduced maximal exercise performance. In the cold, maximal cardiac output is reduced and skin and muscle are vasoconstricted, resulting in a further reduction in exercise capacity.

Preoperative perfusion index as a predictor of post-anaesthetic shivering in caesarean section with spinal anaesthesia

2021 ◽  
pp. 175045892097926
Author(s):  
Mukri P Nasution ◽  
Mariza Fitriati ◽  
Anna S Veterini ◽  
Prihatma Kriswidyatomo ◽  
Arie Utariani
Keyword(s):  
Blood Flow ◽  
Caesarean Section ◽  
Spinal Anaesthesia ◽  
Peripheral Blood ◽  
Elective Caesarean Section ◽  
Perfusion Index ◽  
Peripheral Blood Flow ◽  
Non Invasive ◽  
Flow Perfusion ◽  
Invasive Method

Background Post-anaesthetic shivering is frequently preceded by a decrease in peripheral blood flow. Perfusion index is a fast non-invasive method to assess peripheral blood flow, thus might be correlated with post-anaesthetic shivering. Aim To analyse the relationship between preoperative perfusion index and post-anaesthetic shivering in patients undergoing caesarean section with spinal anaesthesia. Methods In this prospective observational study, preoperative perfusion index measurements were performed on 40 participants who were undergoing elective caesarean section under spinal anaesthesia. Spinal anaesthesia was performed using Lidodex (Lignocaine + Dextrose 5%) at vertebrae L4–L5 or L3–L4 interspace. Shivering was observed until 120 minutes according to the Crossley and Mahajan scale. Statistical analysis was performed to examine the correlation and cut-off of preoperative perfusion index as a predictor for post-anaesthetic shivering. Result There was a significant relationship between preoperative perfusion index with the incidence ( p = 0.005) and the degree ( p = 0.014) of post-anaesthetic shivering. The preoperative perfusion index cut-off value based on the ROC curve was 4.2 (AUC = 0.762, p = 0.002) with a sensitivity of 73.9% and specificity of 88.2%. Participants with preoperative PI < 4.2 had a greater risk of post-anaesthetic shivering ( p < 0.001, RR = 3.13). Conclusion Preoperative perfusion index less than 4.2 can predict post-anaesthetic shivering in patients undergoing caesarean section with spinal anaesthesia.

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