Cardiac output by Modelflow® method from intra-arterial and fingertip pulse pressure profiles

2004 ◽  
Vol 106 (4) ◽  
pp. 365-369 ◽  
Author(s):  
Marcel AZABJI KENFACK ◽  
Federic LADOR ◽  
Marc LICKER ◽  
Christian MOIA ◽  
Enrico TAM ◽  
...  
Keyword(s):  
Cardiac Output ◽  
Steady State ◽  
Radial Artery ◽  
Pulse Pressure ◽  
Pressure Head ◽  
Mean Values ◽  
Pressure Profiles ◽  
Contralateral Hand ◽  
Left Radial Artery ◽  
Q Values

Modelflow®, when applied to non-invasive fingertip pulse pressure recordings, is a poor predictor of cardiac output (Q, litre·min-1). The use of constants established from the aortic elastic characteristics, which differ from those of finger arteries, may introduce signal distortions, leading to errors in computing Q. We therefore hypothesized that peripheral recording of pulse pressure profiles undermines the measurement of Q with Modelflow®, so we compared Modelflow® beat-by-beat Q values obtained simultaneously non-invasively from the finger and invasively from the radial artery at rest and during exercise. Seven subjects (age, 24.0±2.9 years; weight, 81.2±12.6 kg) rested, then exercised at 50 and 100 W, carrying a catheter with a pressure head in the left radial artery and the photoplethysmographic cuff of a finger pressure device on the third and fourth fingers of the contralateral hand. Pulse pressure from both devices was recorded simultaneously and stored on a PC for subsequent Q computation. The mean values of systolic, diastolic and mean arterial pressure at rest and exercise steady state were significantly (P<0.05) lower from the finger than the intra-arterial catheter. The corresponding mean steady-state Q obtained from the finger (Qporta) was significantly (P<0.05) higher than that computed from the intra-arterial recordings (Qpia). The line relating beat-by-beat Qporta and Qpia was y=1.55x-3.02 (r2=0.640). The bias was 1.44 litre·min-1 and the precision was 2.84 litre·min-1. The slope of this line was significantly higher than 1, implying a systematic overestimate of Q by Qporta with respect to Qpia. Consistent with the tested hypothesis, these results demonstrate that pulse pressure profiles from the finger provide inaccurate absolute Q values with respect to the radial artery, and therefore cannot be used without correction with a calibration factor calculated previously by measuring Q with an independent method.

Changes in Radial Artery Pulse Pressure During a Fluid Challenge Cannot Assess Fluid Responsiveness in Patients With Septic Shock

2017 ◽  
Vol 35 (2) ◽  
pp. 149-153
Author(s):  
Victor De la Puente-Diaz de Leon ◽  
Valente de Jesus Jaramillo-Rocha ◽  
Jean-Louis Teboul ◽  
Sofia Garcia-Miranda ◽  
Bernardo A. Martinez-Guerra ◽  
...  
Keyword(s):  
Septic Shock ◽  
Cardiac Output ◽  
Radial Artery ◽  
Pulse Pressure ◽  
Pearson Correlation ◽  
Characteristic Curve ◽  
Fluid Challenge ◽  
Arterial Blood ◽  
Paired Student ◽  
Before And After

Background: Arterial blood pressure is the most common variable used to assess the response to a fluid challenge in routine clinical practice. The aim of this study was to evaluate the accuracy of the change in the radial artery pulse pressure (rPP) to detect the change in cardiac output after a fluid challenge in patients with septic shock. Methods: Prospective observational study including 35 patients with septic shock in which rPP and cardiac output were measured before and after a fluid challenge with 400 mL of crystalloid solution. Cardiac output was measured with intermittent thermodilution technique using a pulmonary artery catheter. Patients were divided between responders (increase >15% of cardiac output after fluid challenge) and nonresponders. The area under the receiver operating characteristic curve (AUROC), Pearson correlation coefficient and paired Student t test were used in statistical analysis. Results: Forty-three percent of the patients were fluid responders. The change in rPP could not neither discriminate between responders and nonresponders (AUROC = 0.52; [95% confidence interval: 0.31-0.72] P = .8) nor correlate ( r = .21, P = .1) with the change in cardiac output after the fluid challenge. Conclusions: The change in rPP neither discriminated between fluid responders and nonresponders nor correlated with the change in cardiac output after a fluid challenge. The change in rPP cannot serve as a surrogate of the change in cardiac output to assess the response to a fluid challenge in patients with septic shock.

scholarly journals Correction of cardiac output obtained by Modelflow® from finger pulse pressure profiles with a respiratory method in humans

2004 ◽  
Vol 106 (4) ◽  
pp. 371-376 ◽  
Author(s):  
Enrico TAM ◽  
Marcel AZABJI KENFACK ◽  
Michela CAUTERO ◽  
Federic LADOR ◽  
Guglielmo ANTONUTTO ◽  
...  
Keyword(s):  
Cardiac Output ◽  
Pulse Pressure ◽  
Open Circuit ◽  
Limits Of Agreement ◽  
Non Invasive ◽  
Pressure Profiles ◽  
Accurate Procedure ◽  
Young Subjects ◽  
Finger Pulse ◽  
Steady State Cycling

The beat-by-beat non-invasive assessment of cardiac output (Q, litre·min-1) based on the arterial pulse pressure analysis called Modelflow® can be a very useful tool for quantifying the cardiovascular adjustments occurring in exercising humans. Q was measured in nine young subjects at rest and during steady-state cycling exercise performed at 50, 100, 150 and 200 W by using Modelflow® applied to the Portapres® non-invasive pulse wave (QModelflow) and by means of the open-circuit acetylene uptake (QC2H2). Q values were correlated linearly (r=0.784), but Bland–Altman analysis revealed that mean QModelflow-QC2H2 difference (bias) was equal to 1.83 litre·min-1 with an S.D. (precision) of 4.11 litre·min-1, and 95% limits of agreement were relatively large, i.e. from -6.23 to +9.89 litre·min-1. QModelflow values were then multiplied by individual calibrating factors obtained by dividing QC2H2 by QModelflow for each subject measured at 150 W to obtain corrected QModelflow (Qcorrected) values. Qcorrected values were compared with the corresponding QC2H2 values, with values at 150 W ignored. Data were correlated linearly (r=0.931) and were not significantly different. The bias and precision were found to be 0.24 litre·min-1 and 3.48 litre·min-1 respectively, and 95% limits of agreement ranged from -6.58 to +7.05 litre·min-1. In conclusion, after correction by an independent method, Modelflow® was found to be a reliable and accurate procedure for measuring Q in humans at rest and exercise, and it can be proposed for routine purposes.

scholarly journals The use of pulse pressure variation for predicting impairment of microcirculatory blood flow

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Christoph R. Behem ◽  
Michael F. Graessler ◽  
Till Friedheim ◽  
Rahel Kluttig ◽  
Hans O. Pinnschmidt ◽  
...  
Keyword(s):  
Blood Flow ◽  
Cardiac Output ◽  
Reperfusion Injury ◽  
Pulse Pressure ◽  
Pulse Pressure Variation ◽  
Ischemia Reperfusion Injury ◽  
Ischemia Reperfusion ◽  
Pressure Variation ◽  
Volume Loading ◽  
Microcirculatory Blood Flow

AbstractDynamic parameters of preload have been widely recommended to guide fluid therapy based on the principle of fluid responsiveness and with regard to cardiac output. An equally important aspect is however to also avoid volume-overload. This accounts particularly when capillary leakage is present and volume-overload will promote impairment of microcirculatory blood flow. The aim of this study was to evaluate, whether an impairment of intestinal microcirculation caused by volume-load potentially can be predicted using pulse pressure variation in an experimental model of ischemia/reperfusion injury. The study was designed as a prospective explorative large animal pilot study. The study was performed in 8 anesthetized domestic pigs (German landrace). Ischemia/reperfusion was induced during aortic surgery. 6 h after ischemia/reperfusion-injury measurements were performed during 4 consecutive volume-loading-steps, each consisting of 6 ml kg−1 bodyweight−1. Mean microcirculatory blood flow (mean Flux) of the ileum was measured using direct laser-speckle-contrast-imaging. Receiver operating characteristic analysis was performed to determine the ability of pulse pressure variation to predict a decrease in microcirculation. A reduction of ≥ 10% mean Flux was considered a relevant decrease. After ischemia–reperfusion, volume-loading-steps led to a significant increase of cardiac output as well as mean arterial pressure, while pulse pressure variation and mean Flux were significantly reduced (Pairwise comparison ischemia/reperfusion-injury vs. volume loading step no. 4): cardiac output (l min−1) 1.68 (1.02–2.35) versus 2.84 (2.15–3.53), p = 0.002, mean arterial pressure (mmHg) 29.89 (21.65–38.12) versus 52.34 (43.55–61.14), p < 0.001, pulse pressure variation (%) 24.84 (17.45–32.22) versus 9.59 (1.68–17.49), p = 0.004, mean Flux (p.u.) 414.95 (295.18–534.72) versus 327.21 (206.95–447.48), p = 0.006. Receiver operating characteristic analysis revealed an area under the curve of 0.88 (CI 95% 0.73–1.00; p value < 0.001) for pulse pressure variation for predicting a decrease of microcirculatory blood flow. The results of our study show that pulse pressure variation does have the potential to predict decreases of intestinal microcirculatory blood flow due to volume-load after ischemia/reperfusion-injury. This should encourage further translational research and might help to prevent microcirculatory impairment due to excessive fluid resuscitation and to guide fluid therapy in the future.

scholarly journals TCT-812 The distal left radial artery for coronary angiography and intervention: A US experience

2018 ◽  
Vol 72 (13) ◽  
pp. B324
Author(s):  
Karim Al-Azizi ◽  
Kyle Gobeil ◽  
Vikram Grewal ◽  
Khawar Maqsood ◽  
Ali Haider ◽  
...  
Keyword(s):  
Coronary Angiography ◽  
Radial Artery ◽  
Left Radial Artery

scholarly journals Do changes in pulse pressure variation and inferior vena cava distensibility during passive leg raising and tidal volume challenge detect preload responsiveness in case of low tidal volume ventilation?

Critical Care ◽  
2021 ◽  
Vol 25 (1) ◽  
Author(s):  
Temistocle Taccheri ◽  
Francesco Gavelli ◽  
Jean-Louis Teboul ◽  
Rui Shi ◽  
Xavier Monnet
Keyword(s):  
Cardiac Output ◽  
Inferior Vena Cava ◽  
Tidal Volume ◽  
Pulse Pressure ◽  
Pulse Pressure Variation ◽  
Inferior Vena ◽  
Vena Cava ◽  
Pressure Variation ◽  
Diagnostic Threshold ◽  
Preload Responsiveness

Abstract Background In patients ventilated with tidal volume (Vt) < 8 mL/kg, pulse pressure variation (PPV) and, likely, the variation of distensibility of the inferior vena cava diameter (IVCDV) are unable to detect preload responsiveness. In this condition, passive leg raising (PLR) could be used, but it requires a measurement of cardiac output. The tidal volume (Vt) challenge (PPV changes induced by a 1-min increase in Vt from 6 to 8 mL/kg) is another alternative, but it requires an arterial line. We tested whether, in case of Vt = 6 mL/kg, the effects of PLR could be assessed through changes in PPV (ΔPPVPLR) or in IVCDV (ΔIVCDVPLR) rather than changes in cardiac output, and whether the effects of the Vt challenge could be assessed by changes in IVCDV (ΔIVCDVVt) rather than changes in PPV (ΔPPVVt). Methods In 30 critically ill patients without spontaneous breathing and cardiac arrhythmias, ventilated with Vt = 6 mL/kg, we measured cardiac index (CI) (PiCCO2), IVCDV and PPV before/during a PLR test and before/during a Vt challenge. A PLR-induced increase in CI ≥ 10% defined preload responsiveness. Results At baseline, IVCDV was not different between preload responders (n = 15) and non-responders. Compared to non-responders, PPV and IVCDV decreased more during PLR (by − 38 ± 16% and − 26 ± 28%, respectively) and increased more during the Vt challenge (by 64 ± 42% and 91 ± 72%, respectively) in responders. ∆PPVPLR, expressed either as absolute or as percent relative changes, detected preload responsiveness (area under the receiver operating curve, AUROC: 0.98 ± 0.02 for both). ∆IVCDVPLR detected preload responsiveness only when expressed in absolute changes (AUROC: 0.76 ± 0.10), not in relative changes. ∆PPVVt, expressed as absolute or percent relative changes, detected preload responsiveness (AUROC: 0.98 ± 0.02 and 0.94 ± 0.04, respectively). This was also the case for ∆IVCDVVt, but the diagnostic threshold (1 point or 4%) was below the least significant change of IVCDV (9[3–18]%). Conclusions During mechanical ventilation with Vt = 6 mL/kg, the effects of PLR can be assessed by changes in PPV. If IVCDV is used, it should be expressed in percent and not absolute changes. The effects of the Vt challenge can be assessed on PPV, but not on IVCDV, since the diagnostic threshold is too small compared to the reproducibility of this variable. Trial registration: Agence Nationale de Sécurité du Médicament et des Produits de santé: ID-RCB: 2016-A00893-48.

SEMI INVASIVE CARDIAC OUTPUT MONITORING IN A CARDIAC PATIENT UNDERGOING TOTAL THYROIDECTOMY USING SMARTPHONE APP CAPSTESIA.

2021 ◽  
pp. 4-5
Author(s):  
Santosh Kumar Rai ◽  
Vishal Vashist ◽  
Deepak Bhardwaj ◽  
Bhanu Gupta
Keyword(s):  
Cardiac Output ◽  
Cardiac Index ◽  
Real Time ◽  
Hemodynamic Monitoring ◽  
Pulse Pressure ◽  
Pulse Pressure Variation ◽  
Output Pulse ◽  
Pressure Variation ◽  
Smartphone App ◽  
Arterial Waveform

Introduction: Advanced hemodynamic monitoring is need of today especially in patients with limited cardiac reserve. With the advent of smartphones & specially designed applications, hemodynamic monitoring becomes quite easy. Materials & Methods: Patient was pre – medicated with Inj. Fentanyl & inj. Glycopyrrolate, induced with Inj. Etomidate & Inj. Vecuronium and maintained with mixture ofIsourane, Nitrous Oxide & Oxygen. An arterial line was secured in Left Radial Artery. We used the CAPSTESIA app to take picture of the arterial waveform using a smartphone. Demographic data of the patient was fed in the app. App used it's pre- fed algorithm to give the real time Cardiac Output, Pulse Pressure variations, Cardiac Index based upon the arterial waveform. Results: Using the application we were able to monitor the cardiac output of the patient in real time using semi- invasive means. It enabled us to regulate the uid management of the patient and avoid any adverse cardiac events (hypotension). With Pulse Pressure variation also available in real time, we were able to restrict use of vasopressors since the Left Ventricle Ejection Fraction of the patient was 35 % on ECHO. Surgery was conducted without any untoward event. Patient was successfully extubated and sent to PACU. Conclusions:Advanced hemodynamic monitoring is time consuming using manual methods. We found the smartphone app CAPSTESIA pretty useful for semi-invasive hemodynamic monitoring of the Cardiac Output, Pulse Pressure variation, Cardiac Index,etc in real time.

Evaluation of cardiac output variations with the peripheral pulse pressure to mean arterial pressure ratio

2018 ◽  
Vol 33 (4) ◽  
pp. 581-587 ◽  
Author(s):  
Audrey Tantot ◽  
Anais Caillard ◽  
Arthur Le Gall ◽  
Joaquim Mateo ◽  
Sandrine Millasseau ◽  
...  
Keyword(s):  
Cardiac Output ◽  
Mean Arterial Pressure ◽  
Arterial Pressure ◽  
Pulse Pressure ◽  
Pressure Ratio ◽  
Peripheral Pulse

Physiological and biophysical limits to work in the heat for clothed men and women

1978 ◽  
Vol 44 (6) ◽  
pp. 918-925 ◽  
Author(s):  
E. Kamon ◽  
B. Avellini ◽  
J. Krajewski
Keyword(s):  
Steady State ◽  
Vapor Pressure ◽  
Physiological Responses ◽  
Men And Women ◽  
Mean Values ◽  
Air Temperatures ◽  
Significant Difference ◽  
The Mean ◽  
Evaporative Heat Transfer ◽  
The One

Heat-acclimated, lightly clothed men and women (four of each) walked on a treadmill at 25% and 43% VO2 max, respectively, (M =194 W.m-2), under seven air temperatures (Ta) ranging from 36 to 52 degrees C. Each experiment involved 1 h of fixed and a 2nd h of progressively increasing ambient vapor pressure (Pa). The relative steady state of rectal temperature (Tre), mean skin temperature (Tsk), and heart rate (HR) reached in the 1st h were forced upward during the 2nd h by the rising Pa. The critical air vapor pressure (Pcrit) was identified by the Tre point of inflection for each Ta. One man did not fully reach steady state, but inflection could be determined for his physiological responses. The mean values of all points of inflection were calculated for Tre, Tsk, and HR. Significant sex difference in HR was found only by excluding the results of the one man. Tre and Tsk showed no significant difference between men and women. The coefficient for evaporative heat transfer (he), which could be derived using the Pcrit for the low Ta range, was 14.5 +/- 2.2 W.m-1 Torr-1.

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