Nichtinvasive Blutdruckmessung mit Highdefinition- oscillometry-Technik bei Pferden mit Herzerkrankungen

Bei dem arteriellen Blutdruck handelt es sich um das Produkt aus dem Herzminutenvolumen und dem totalen peripheren Widerstand (HMV x TPW). Die zentrale Regulation des Blutdruckes findet in der Medulla oblongata statt, während Chemo - und Barorezeptoren in den peripheren Gefäßen Informationen dorthin übermitteln. Während die intraarterielle Blutdruckmessung noch immer als Goldstandart gilt, wurde im Rahmen dieser Arbeit eine neue Technik der nichtinvasiven Blutdruckmessung erprobt.
In der vorliegenden Studie wurde sowohl der systolische, diastolische als auch der mittlere arterielle Blutdruck nichtinvasiv mittels High definition oscillometry - Technik an der Arteria coccygealis bestimmt. Als zentraler Kreislaufparameter wurde das Herzminutenvolumen dopplerechokardiographisch (PW - Doppler) an der Arteria pulmonalis untersucht. Einen peripheren Kreislaufparameter stellte das Blutflussvolumen an der Arteria digitalis palmaris dar, welches ebenfalls mit Hilfe des PW - Dopplers gemessen wurde. Des Weiteren wurde die maximale systolische und die enddiastolische Flussgeschwindigkeit des Blutes sowie der Resistance - Index bestimmt.
Zusätzlich wurde der Einfluss verschiedener häufig vorkommender Herzerkrankungen wie der Mitralklappeninsuffizienz, Aortenklappeninsuffizienz und Vorhofflimmern beim Pferd auf diese Parameter untersucht.
Ziel dieser Studie war es, neben der Erprobung des HDO - Gerätes, Vergleichswerte für den systolischen (SAP), diastolischen (DAP) und mittleren arteriellen Blutdruck (MAP) für gesunde Pferde und Pferde mit unterschiedlichen Herzerkrankungen zu erstellen, um gegebenenfalls eine Verlaufs- und Behandlungskontrolle zu ermöglichen.
Das Probandengut bestand aus 30 herzgesunden Pferden und 30 Pferden mit unterschiedlichen Herzerkrankungen (13 x Mitralklappeninsuffizienz, 11 x Aortenklappeninsuffizienz, 6 x Vorhofflimmern). Bei 18 herzkranken und 18 herzgesunden Pferden wurden die Blutdruckmessungen morgens und abends durchgeführt, um eine gegebenenfalls vorhandene zirkadiane Rhythmik nachzuweisen.
Die Blutdruckmessung wurde mittels Schweifmanschette, HDO - Gerät und angeschlossenem Laptop durchgeführt.
Zur dopplerechokardiographischen Bestimmung des Herzminutenvolumens wurde die Arteria pulmonalis in der rechten kranialen langen Achse (RKRLA) angeschallt. Im B - Mode wurde der Durchmesser der Pulmonalarterie gemessen und mit Hilfe des PW - Dopplers wurde das Velocity time integral (VTI) abgeleitet. Das Messvolumen befand sich hierfür auf Höhe des Schlusses der Pulmonalklappensegel.
Die Messung des Blutflussvolumens an der lateralen Zehenarterie wurde an der rechten Vordergliedmaße durchgeführt. Im B - Mode - Bild wurde der Gefäßdurchmesser bestimmt und die Geschwindigkeitsmessung des Blutflusses wurde mit dem PW - Doppler durchgeführt.
Die Blutdruckwerte gesunder Pferde lagen bei: SAP 145 (± 21) mmHg, DAP 97 (± 19) mmHg und MAP 114 (± 19) mmHg. Im Vergleich zu den Blutdruckwerten herzkranker Pferde ließen sich keine signifikanten Unterschiede feststellen. Es zeigte sich jedoch, dass Pferde mit einer Aortenklappeninsuffizienz einen tendenziell höheren (SAP 149 mmHg, MAP 114 mmHg, DAP 94 mmHg) und Pferde mit Vorhofflimmern einen tendenziell niedrigeren systolischen arteriellen Blutdruck (SAP 130 mmHg, MAP 105 mmHg, DAP 91 mmHg) aufwiesen als die herzgesunden Tiere. Pferde, die an einer Mitralklappeninsuffizienz litten zeigten folgende Blutdruckwerte: SAP 143 mmHg, MAP 115 mmHg, DAP 98 mmHg.
Bezüglich der diurnalen Rhythmik des Blutdruckes wurde bei den gesunden Pferden ein geringgradiger Anstieg des systolischen arteriellen Blutdruckes bei der späten Messung festgestellt, während die herzkranken Pferde abends einen nicht signifikant niedrigeren Blutdruck als am Morgen aufwiesen.
Der Blutdruck, das Herzminutenvolumen und das Blutflussvolumen an der Zehenarterie stellten den aktuellen Kreislaufzustand des Pferdes dar, wiesen jedoch keine signifikanten Korrelationen auf.
Anhand dieser Studie konnte gezeigt werden, dass mit der High definition oscillometry - Technik eine adäquate indirekte Blutdruckmessung beim Pferd möglich ist und die Schweifrübe eine geeignete Lokalisation zum Anlegen der Manschette darstellt. Diese Technik zur Blutdruckmessung bietet den Vorteil der Visualisierung der Blutdruckkurve am Monitor, was das Erkennen und Beurteilen einer Arrhythmie vereinfacht. Die Anwendung eines spezifischen Algorithmus ermöglicht die Unterscheidung zwischen Druckwelle und Artefakt. Allerdings eignet sich die Blutdruckmessung nicht für Verlaufskontrollen einer Herzerkrankung oder Therapiekontrollen beim Pferd. Noninvsive blood pressure measurement by high-definition-oscillometry in horses with heart diseases

The arterial blood pressure is defined as the product of cardiac output and arterial resistance (afterload). Central modulation of blood pressure occurs in the medulla oblongata, while the information is sent from receptor cells in the peripheral blood vessels. Until recently the direct measurement of blood pressure has been considered as the gold standard, while in this study a new indirect technique is used.
In this study we determined the systolic, diastolic and mean arterial pressure noninvasively in the coccygeal artery by the High - Definition - Oscillometry - Technique (HDO). As a parameter for central circulation we examined the cardiac output at the pulmonary artery via Doppler - echocardiography. As a peripheral parameter for circulation we measured the blood flow in the digital artery by Doppler sonography. In addition we defined the systolic peak velocity and the enddiastolic velocity of the digital blood flow as well as the resistance - index.
Furthermore the influence of different common heart diseases in horses (mitral valve insufficiency, aortic valve insufficiency, atrial fibrillation) on these parameters was examined.
The intent of this study was testing the HDO - machine, to define reference values of systolic (SAP), diastolic (DAP) and mean arterial pressure (MAP) in healthy horses and horses diagnosed with different cardiac diseases. This could be important to achieve information regarding the development of disease and to monitor therapy.
30 horses considered to be healthy, while in 30 further horses, different kinds of cardiac diseases were found (13 x mitral valve insufficiency, 11 x aortic valve insufficiency, 6 x atrial fibrillation). Regarding diurnal variations of blood pressure in horses, 18 healthy horses and 18 horses with heart disease were measured in the morning and in the evening. Blood pressure measurements were performed via tail cuff and using HDO equipment connected to a laptop.
To determine cardiac output per minute the pulmonary artery was scanned in the right ventricular outflow tract. In B - mode imaging the diameter of the artery was measured. By pulsed - wave - Doppler we assigned the velocity time integral (VTI), therefore the cursor was positioned on a level with pulmonary artery closure.
On the right front limb we performed blood flow measurement at the lateral digital artery. The vessel diameter was affected by B - mode - imaging and the velocity was measured by pulsed - wave Doppler.
In our study population the following average blood pressures were measured: SAP 145 (± 21) mmHg, DAP 97 (± 19) mmHg, MAP 114 (± 19) mmHg. No significant difference could be determined between healthy horses and horses with heart diseases. An insufficiency of the aortic valve tends to result in higher systolic arterial pressure (SAP 149 mmHg, MAP 114 mmHg, DAP 94 mmHg), whereas atrial fibrillation causes lower blood pressure (SAP 130 mmHg, MAP 105 mmHg, DAP 91 mmHg) compared to healthy horses. Horses suffering from mitral valve insufficiency showed following values: SAP 143 mmHg, MAP 115 mmHg, DAP 98 mmHg.
Regarding the diurnal rhythm of blood pressure, healthy hoses showed a slight increase of the systolic arterial pressure in the evening, whereas horses suffering from heart disease showed a systolic arterial pressure that was non-significantly lower in the evening than in the morning.
Blood pressure, cardiac output and blood flow in the digital artery demonstrate the current state of circulation in the horse, but there is no significant correlation between these parameters.
This study showed that the new High - Definition - Oscillometry technique is a meaningful method of indirect blood pressure measurement in horses. The tail root was shown to be an adequate localization for the cuff. The advantage of this type of blood pressure measurement is the possibility to visualize the blood pressure curve on a monitor. This facilitates recognizing and evaluating an arrhythmia. The application of a specific algorithm permits differentiation between compression waves and artifacts.
Finally, we wish to stress that the measurement of blood pressure cannot be considered a suitable method for monitoring the development or therapy of cardiac disease.

Noninvsive blood pressure measurement by high-definition-oscillometry in horses with heart diseases

The arterial blood pressure is defined as the product of cardiac output and arterial resistance (afterload). Central modulation of blood pressure occurs in the medulla oblongata, while the information is sent from receptor cells in the peripheral blood vessels. Until recently the direct measurement of blood pressure has been considered as the gold standard, while in this study a new indirect technique is used.
In this study we determined the systolic, diastolic and mean arterial pressure noninvasively in the coccygeal artery by the High - Definition - Oscillometry - Technique (HDO). As a parameter for central circulation we examined the cardiac output at the pulmonary artery via Doppler - echocardiography. As a peripheral parameter for circulation we measured the blood flow in the digital artery by Doppler sonography. In addition we defined the systolic peak velocity and the enddiastolic velocity of the digital blood flow as well as the resistance - index.
Furthermore the influence of different common heart diseases in horses (mitral valve insufficiency, aortic valve insufficiency, atrial fibrillation) on these parameters was examined.
The intent of this study was testing the HDO - machine, to define reference values of systolic (SAP), diastolic (DAP) and mean arterial pressure (MAP) in healthy horses and horses diagnosed with different cardiac diseases. This could be important to achieve information regarding the development of disease and to monitor therapy.
30 horses considered to be healthy, while in 30 further horses, different kinds of cardiac diseases were found (13 x mitral valve insufficiency, 11 x aortic valve insufficiency, 6 x atrial fibrillation). Regarding diurnal variations of blood pressure in horses, 18 healthy horses and 18 horses with heart disease were measured in the morning and in the evening. Blood pressure measurements were performed via tail cuff and using HDO equipment connected to a laptop.
To determine cardiac output per minute the pulmonary artery was scanned in the right ventricular outflow tract. In B - mode imaging the diameter of the artery was measured. By pulsed - wave - Doppler we assigned the velocity time integral (VTI), therefore the cursor was positioned on a level with pulmonary artery closure.
On the right front limb we performed blood flow measurement at the lateral digital artery. The vessel diameter was affected by B - mode - imaging and the velocity was measured by pulsed - wave Doppler.
In our study population the following average blood pressures were measured: SAP 145 (± 21) mmHg, DAP 97 (± 19) mmHg, MAP 114 (± 19) mmHg. No significant difference could be determined between healthy horses and horses with heart diseases. An insufficiency of the aortic valve tends to result in higher systolic arterial pressure (SAP 149 mmHg, MAP 114 mmHg, DAP 94 mmHg), whereas atrial fibrillation causes lower blood pressure (SAP 130 mmHg, MAP 105 mmHg, DAP 91 mmHg) compared to healthy horses. Horses suffering from mitral valve insufficiency showed following values: SAP 143 mmHg, MAP 115 mmHg, DAP 98 mmHg.
Regarding the diurnal rhythm of blood pressure, healthy hoses showed a slight increase of the systolic arterial pressure in the evening, whereas horses suffering from heart disease showed a systolic arterial pressure that was non-significantly lower in the evening than in the morning.
Blood pressure, cardiac output and blood flow in the digital artery demonstrate the current state of circulation in the horse, but there is no significant correlation between these parameters.
This study showed that the new High - Definition - Oscillometry technique is a meaningful method of indirect blood pressure measurement in horses. The tail root was shown to be an adequate localization for the cuff. The advantage of this type of blood pressure measurement is the possibility to visualize the blood pressure curve on a monitor. This facilitates recognizing and evaluating an arrhythmia. The application of a specific algorithm permits differentiation between compression waves and artifacts.
Finally, we wish to stress that the measurement of blood pressure cannot be considered a suitable method for monitoring the development or therapy of cardiac disease.