Compendium The SOMNOmedics Pulse Transit Time (PTT) Method – Blood Pressure Measurement Reinvented  non-invasive  continous  cuf

SOMNOmedics GmbH Am Sonnenstuhl 63 D-97236 Randersacker Germany Tel.: +49 931 359094-0 Fax: +49 931 359094-49 www.somnomedics.eu [email protected]

FOREWORD Now more than ever medical technology must be oriented to the latest medical research and the increased needs of doctors and patients. In particular, the rapidly developing field of sleep medicine requires ground-breaking, forward-thinking solutions. We began in sleep medicine and see ourselves as specialists in polysomnography and cardio-respiratory screenings. Thanks to our experience of more than 20 years, we have also been able to tap into the fields of cardiology and neurology. Today we offer sophisticated solutions for diagnostic long-term EEGs, long-term ECGs and ambulatory blood...

1. Long-term Blood Pressure Measurements 2. Long-term Blood Pressure Measurements according to Riva-Rocci – is the Method State-of-the-art? 3. Continuous, Non-reactive BP Measurement using Pulse Transit Time (PTT) Recording BP using the PTT Method 5. Areas of Application for the SOMNOtouch™ NIBP ▶ BP Analysis during the Daytime ▶ BP Analysis during Sleep ▶ Clinical Relevance: Nocturnal Blood Pressure Fluctuations (NBPF) and Superposition ▶ Clinical Relevance: The Effect of CPAP Therapy on Nocturnal Blood Pressure Fluctuations 18 ▶ Clinical Relevance: Nocturnal Blood Pressure and Restless Leg...

9. VALIDATIONS of the PTT Method ▶ Validations at a Glance 9.1 Validation of the SOMNOtouch™ NIBP according to the ESH (European Society of Hypertension) International Protocol 9.2 Comparison of the PTT Method against CUFF-BASED Method: during ERGOMETRY Comparison of the PTT Method against CUFF-BASED Method: over 24 HOURS Comparison of the PTT Method against CUFF-BASED Method: during different breathing maneuvers Comparison of the PTT Method against CUFF-BASED Method and INTRA-ARTERIAL Measurement Comparison of the PTT Method against PENAZ-Method Comparison of the PTT Method against INVASIVE...

LONG-TERM BLOOD PRESSURE MEASUREMENTS Arterial hypertension (high blood pressure) is a very common disease - affecting about 30% of the world‘s population [1]. High blood pressure is one of the main risk factors for cardiovascular diseases such as coronary heart disease, heart attack, stroke and peripheral artery disease. Often, however, arterial hypertension is a symptomless condition, making detection of this disease more difficult. The current European guidelines (ESH/ESC Guidelines 2018) suggest, in addition to the formerly recommended office blood pressure (BP) measurements, the broader...

Normally, in healthy persons, BP drops during night by 10% to 20% of daytime average (dipper; [4]). Patients in whom the nocturnal BP drop is less pronounced (non-dipper) or in whom BP even rises during night (inverted dipper) have an increased cardiovascular risk in cardiovascular morbidity and mortality. It is only possible to record this important BP behaviour at night with a 24 h ABPM. Additionally, ABPM allows the exclusion of a socalled office hypertension („white-coat hypertension“). Here, high BP levels are only measured in a medical environment like in the clinic or office, while selfmeasurement...

LONG-TERM BLOOD PRESSURE MEASUREMENTS ACCORDING TO RIVA-ROCCI – IS THE METHOD STATE-OF-THE-ART? The cuff-based method for measuring BP was introduced in 1896 by Scipione Riva-Rocci. To this day, long-term BP measurements are usually carried out with automated devices based on this method. Using this method, measurements are taken four times per hour during day and twice per hour during night (10 pm- 6 am). However, for 24 h BP measurements these requirements cannot always be met: • The patients should follow their daily routine. However, this would mean that they cannot possibly be still during...

CONTINUOUS, NON-REACTIVE BP MEASUREMENT USING PULSE TRANSIT TIME (PTT) The PTT-BP Relationship The PTT (pulse transit time) describes the time a pulse pressure wave needs to cover the distance between two points within the arterial system – in our case from the left ventricle of the heart (defined by the R-peak of the ECG) to the fingertip (detected by plethysmography). By using the distance (d = running distance from the heart to the fingertip) the pulse wave velocity (PWV) can be determined from the PTT: PWV directly depends on the elasticity modulus (also stiffness) of the blood vessel (E):...

Recording BP using the PTT Method Measuring the PTT is a simple method for determining a person’s blood pressure. As such, the interval between the R-wave of the ECG and the arrival of the corresponding pulse wave at the peripheral site (the finger) is measured. The turning point of the finger pulse curve is taken as indicator for the arrival of the pulse wave The calculation of systolic (SBP) and diastolic blood pressure (DBP) is based on a non-linear correlation between BP (in mmHg) and PTT (in ms) [5]. The PTT method is patented [6] and clinically validated, e.g. according the ESH International...

With a one-point calibration during the ongoing measurement, the current BP and the vessel properties are recorded and the BP-PWV relation is individually corrected. By adding the patient‘s body size (to determine the running distance of the pulse wave), an accurate SBP and DBP value can be calculated for each PTT value. Blood Pressure Gauge Figure 5 One-point calibration (Source: SOMNOmedics). Beat-to-beat determination of SBP and DBP by one-point calibration from systolic and diastolic PTT.

The SOMNOtouch™ NIBP is an ambulatory BP device for continuous, non-invasive and non-reactive determination of SBP and DBP with a recording duration of up to 24 hours. By simultaneously recording the ECG and finger plethysmogram (including oxygen saturation), the PTT can be calculated by the software. The exact values for SBP and DBP are displayed on the colour touch screen display. Figure 6 The SOMNOtouch™ NIBP device and application of sensors (Source: SOMNOmedics). More than just an ambulatory BP recording device  Syst./diast. BP, beat-to-beat  3-channel ECG  SpO2, pulse rate  Plethysmogram...