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Cardiac Output

Calculators  Cardiovascular
This calculator measures cardiac output by assessing O2 use in the body. Arterial oxygen content is measured using the pulmonary vein oxygen levels, and venous oxygen content is measured using the pulmonary artery oxygen levels. Arterial oxygen content represents oxygenated blood, and venous oxygen content represents deoxygenated blood. Cardiac output is then determined by dividing oxygen consumption by the subtraction of venous oxygen content from arterial oxygen content.
O2 Consumption
m
Hgb
g
O2Sat
%
PaO2
m
O2vSat
%
PvO2
m
Result:

Background

Measured Factor
This calculator measures cardiac output of the heart based on the use of oxygen by the body.
Measured Factor Disease
  • Increased mortality risk
  • Cardiogenic shock
  • High output heart failure
  • Chronic anemia
  • Systemic arterio-venous fistulae
  • Sepsis
  • Hypercapnia
  • Hyperthyroidism
Measured Factor Detail
Cardiac output is the ability of the heart to pump blood to the rest of the body. This is measured by assessing the use of oxygen in the body's various organs. When the blood comes to the heart from the lungs, it is oxygenated. Once it is pumped into the body and reaches the tissues, it becomes deoxygenated as the body uses the oxygen. Measuring caridac output by oxygen content assesses the ability of the body to use oxygen as well as the ability of the blood to contain oxygen. Because oxygen is used by every organ in the body, it is easy to use when assessing perfusion throughout the body. Cardiac output is often monitored before, during, and after operations to ensure the health of the heart and to determine the workload the heart is undergoing.
Speciality
Cardiologist
Body System
Cardiovascular
Formula
Arterial Oxygen Content (CaO2) = (Hgb * 13.4 * O2Sat/100) + (PaO2 * 0.031) Venous Oxygen Content (CvO2) = (Hgb * 13.4 * O2vSat/100) + (PvO2 * 0.031) Cardiac output (CO) = O2Consumption / (CaO2 - CvO2) Hgb: Hemoglobin O2Sat: Oxyhemoglobin saturation (arterial) O2vSat : Oxyhemoglobin saturation (venous) PaO2: Partial pressure of oxygen (arterial) PvO2: Partial pressure of oxygen (venous)
Measured Factor Low Impact
  • Increased mortality risk
  • Cardiogenic shock
Measured Factor High Impact
  • High output heart failure
  • Chronic anemia
  • Systemic arterio-venous fistulae
  • Sepsis
  • Hypercapnia
  • Hyperthyroidism

Result Interpretation

Ranges Ranges
  • Normal: Results vary depending on the body's metabolic needs
  • Normal Adult Male: Results vary depending on the body's metabolic needs
  • Normal Adult Female: Results vary depending on the body's metabolic needs
  • Normal Pediatric: Results vary depending on the body's metabolic needs
  • Normal Geriatric Male: Results vary depending on the body's metabolic needs
  • Normal Geriatric Female: Results vary depending on the body's metabolic needs
Result Low Conditions
  • Increased mortality risk
  • Cardiogenic shock
Result High Conditions
  • High output heart failure
  • Chronic anemia
  • Systemic arterio-venous fistulae
  • Sepsis
  • Hypercapnia
  • Hyperthyroidism
Test Limitations
One limitation of the test is the requirement for invasive blood sampling. Moreover, the accuracy of the test is limited by presence of air leakage, cardiopulmonary disease, and enhanced pulmonary oxygen consumption (for example in preterm infants with chronic lung disease).
References: 6

Studies

Study Validation 1
This study compared the use of ultrasound dilution technique to the Fick Principle to measure caridac output in children who were critically ill. The study was designed to determine the efficacy of the ultrasound dilution technique. The prospective, single-center study included 26 children. The data from each method of measuring cardiac output was analyzed using linear regression. The Fick principle measured cardiac output at an average of 3.76 L/min, and the ultrasound dilution technique measured cardiac output at an average of 3.49 L/min. This showed that the two methods are noninferior in measuring cardiac output (p<0.0001). The results remained accurate for children under 20 kg as well, with an average caridac output of 2.46 L/min via Fick and 2.27 L/min via ultrasound (p<0.0001). The researchers determined that the ultrasound technique is equivalent to the Fick Principle in measuring cardiac output, although more research is needed to exapnd the uses and limitations of the ultrasound technique.
References: 7
Study Validation 2
This study was designed to determine the efficacy of cardiac output measurments in ventilated children and infants. This prospective, comparison study included 24 children. Caridac output was assessed using the Fick Principle after gathering oxygen values from arterial and venous blood samples. This was compared to the Femoral Arterial Thermodilution (FATD) method of determining cardiac output. The Fick Principle and the FATD method had mean values of 2.55 L/min and 2.51 L/min, respectively. The study researchers concluded that FATD compares favourably with Fick estimates in ventilated children and infants.
References: 8
Study Additional 1
This study compared the pros and cons of the various methods of determining cardiac output in children. The study's goal was to determine if there was a superior method to assess cardiac output, and whether cardiac monitoring would affect morbidity and mortality in pediatric patients. The researcher found that the Fick principle is currently the gold standard for assessing cardiac output, but it is also an invasive test which can have negative effects on children. It also requires blood sampling which may lead to complications in children. The researcher concluded that more research is required to further assess and refine the various techniques available in order to increase accuracy and safety in the pediatric population.
References: 6
Study Additional 2
This study assessed the use of continuous Fick cardiac output measurement in exercise testing to determine whether the Fick principle may be applied to this area of study. The study included 17 patients with a past medical history of mycardial infarction. These patients underwent a 1 or 3 minute incremental exercise stress test. Cardiac output was measured every 12 seconds using the Fick principle. This was compared to values obtained through the thermodilution method. The two methods showed high correlation in both the 1 minute and 3 minute groups (r=0.86, r=0.8). The researchers concluded that continuous Fick method may be applied to determine cardiac output during exercise.
References: 9

Authors

Adolf Eugen Fick (1829–1901) was a physician and physiologist. He received his M.D. degree from the University of Marburg in 1851. He developed the direct Fick method for measuring cardiac output and Fick's laws of diffusion.
http://anesthesiology.pubs.asahq.org/article.aspx?articleid=1948127

References

  1. Fick, A. Über die Messung des Blutquantums in den Herzventrikeln. Sitzungsberichte der Physiologisch-Medizinischen Gesellschaft zu Würzburg. 1870; 2: 16 (article in German)
  2. Perry DA, Thomson LM, Pigula FA, Polizzotti BD, DiNardo JA, Nedder A, et al. Changes in tissue oxygen tension, venous saturation, and Fick-based assessments of cardiac output during hyperoxia. Acta Anaesthesiol Scand. 2018 Aug 14
  3. De Boode WP. Cardiac output monitoring in newborns. Early Hum Dev. 2010 Mar;86(3):143-8.
  4. Brissaud O, Botte A, Cambonie G, Dauger S, de Saint Blanquat L, Durand P, et al. Experts' recommendations for the management of cardiogenic shock in children. Ann Intensive Care. 2016 Dec;6(1):14.
  5. Mehta PA, Dubrey SW. High output heart failure. QJM. 2009 Apr;102(4):235-41.
  6. De Boode WP. Cardiac output monitoring in newborns. Early Hum Dev. 2010 Mar;86(3):143-8.
  7. Boehne M, Baustert M, Paetzel V, Köditz H, Schoof S, Happel CM, et al. Determination of cardiac output by ultrasound dilution technique in infants and children: a validation study against direct Fick principle. Br J Anaesth. 2014 Mar;112(3):469-76.
  8. Tibby SM, Hatherill M, Marsh MJ, Morrison G, Anderson D, Murdoch IA. Clinical validation of cardiac output measurements using femoral artery thermodilution with direct Fick in ventilated children and infants. Intensive Care Med. 1997 Sep;23(9):987-91.
  9. Nakanishi N, Yoshioka T, Okano Y, Nishimura T. Continuous Fick cardiac output measurement during exercise by monitoring of mixed venous oxygen saturation and oxygen uptake. Chest. 1993 Aug;104(2):419-26.