Theoretical models of retinal hemodynamics showed the modulation of retinal pulsatile patterns (RPPs) by heart rate (HR), yet in-vivo validation and scientific merit of this biological process is lacking. Such evidence is critical for result interpretation, study design, and (patho-)physiological modeling of human biology spanning applications in various medical specialties. In retinal hemodynamic video-recordings, we characterize the morphology of RPPs and assess the impact of modulation by HR or other variables. Principal component analysis isolated two RPPs, i.e., spontaneous venous pulsation (SVP) and optic cup pulsation (OCP). Heart rate modulated SVP and OCP morphology (pFDR < 0.05); age modulated SVP morphology (pFDR < 0.05). In addition, age and HR demonstrated the effect on between-group differences. This knowledge greatly affects future study designs, analyses of between-group differences in RPPs, and biophysical models investigating relationships between RPPs, intracranial, intraocular pressures, and cardiovascular physiology.
- MeSH
- discus nervi optici * MeSH
- lidé MeSH
- nitrooční tlak MeSH
- pulzatilní průtok fyziologie MeSH
- srdeční frekvence MeSH
- vena centralis retinae * fyziologie MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
BACKGROUND: Noninvasive diagnostic methods utilizing pulse wave measurements on the surface of the head are an important tool in diagnosing various types of cerebrovascular disease. The measurement of extraorbital pressure fluctuations reflects intraocular and intracranial pressure changes and can be used to estimate pressure changes in intracranial arteries and the collateral circulation. NEW METHOD: In this paper, we describe our patented (CZ 305757) digital device for noninvasive measuring and monitoring of orbital movements using pressure detection. We conducted preclinical tests (126 measurements on 42 volunteers) to evaluate the practical capabilities of our device. Two human experts visually assessed the quality of the pressure pulsation and discriminability among various test conditions (specifically, subject lying, sitting, and the Matas carotid occlusion test). RESULTS: The results showed that our device provided clinically relevant outcomes with a sufficient level of detail of the pulse wave and a high reliability (not less than 85%) in all clinically relevant situations. It was possible to record the effect of the Matas carotid occlusion test. COMPARISON WITH EXISTING METHOD(S): Our fully noninvasive, lightweight (185 g), portable, and wireless device provides a considerably cheaper alternative to the current diagnostic methods (e.g., transcranial ultrasound, X-ray, or MRI angiography) for specific assessment of cerebral circulation. Within a minute, it can detect the Willis circle integrity and thus eliminate the potential risks associated with the Matas test using standard EEG. CONCLUSIONS: Our device represents an improvement and a valid alternative to the current methods diagnosing regional cerebral circulation.
- MeSH
- circulus arteriosus Willisi fyziologie MeSH
- design vybavení * MeSH
- lidé MeSH
- mozkový krevní oběh fyziologie MeSH
- orbita * krevní zásobení MeSH
- pletysmografie přístrojové vybavení normy MeSH
- pulzatilní průtok fyziologie MeSH
- regionální krevní průtok fyziologie MeSH
- reprodukovatelnost výsledků MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
INTRODUCTION: Long-term use of continuous-flow left ventricular assist devices may have negative consequences for autonomic, cardiovascular and gastrointestinal function. It has thus been suggested that non-invasive monitoring of arterial pulsatility in patients with a left ventricular assist device is highly important for ensuring patient safety and longevity. We have developed a novel, semi-automated frequency-domain-based index of arterial pulsatility that is obtained during suprasystolic occlusions of the upper arm: the 'cuff pulsatility index'. PURPOSE: The purpose of this study was to evaluate the relationship between the cuff pulsatility index and invasively determined arterial pulsatility in patients with a left ventricular assist device. METHODS: Twenty-three patients with a left ventricular assist device with end-stage heart failure (six females: age = 65 ± 9 years; body mass index = 30.5 ± 3.7 kg m-2) were recruited for this study. Suprasystolic occlusions were performed on the upper arm of the patient's dominant side, from which the cuff pressure waveform was obtained. Arterial blood pressure was obtained from the radial artery on the contralateral arm. Measurements were obtained in triplicate. The relationship between the cuff pressure and arterial blood pressure waveforms was assessed in the frequency-domain using coherence analysis. A mixed-effects approach was used to assess the relationship between cuff pulsatility index and invasively determined arterial pulsatility (i.e. pulse pressure). RESULTS: The cuff pressure and arterial blood pressure waveforms demonstrated a high coherence up to the fifth harmonic of the cardiac frequency (heart rate). The cuff pulsatility index accurately tracked changes in arterial pulse pressure within a given patient across repeated measurements. CONCLUSIONS: The cuff pulsatility index shows promise as a non-invasive index for monitoring residual arterial pulsatility in patients with a left ventricular assist device across time.
- MeSH
- arterie patofyziologie MeSH
- asistovaná cirkulace přístrojové vybavení metody MeSH
- diagnostické techniky kardiovaskulární MeSH
- krevní tlak fyziologie MeSH
- lidé středního věku MeSH
- lidé MeSH
- podpůrné srdeční systémy * MeSH
- pulz metody MeSH
- pulzatilní průtok fyziologie MeSH
- reprodukovatelnost výsledků MeSH
- senioři MeSH
- srdeční selhání * patofyziologie terapie MeSH
- Check Tag
- lidé středního věku MeSH
- lidé MeSH
- mužské pohlaví MeSH
- senioři MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
In the pulmonary circulation, resistive and compliant properties overlap in the same vessels. Resistance varies nonlinearly with pressure and flow; this relationship is driven by the elastic properties of the vessels. Linehan et al. correlated the mean pulmonary arterial pressure and mean flow with resistance using an original equation incorporating the distensibility of the pulmonary arteries. The goal of this study was to validate this equation in an in vivo porcine model. In vivo measurements were acquired in 6 pigs. The distensibility coefficient (DC) was measured by placing piezo-electric crystals around the pulmonary artery (PA). In addition to experiments under pulsatile conditions, a right ventricular (RV) bypass system was used to induce a continuous pulmonary flow state. The Linehan et al. equation was then used to predict the pressure from the flow under continuous flow conditions. The diameter-derived DC was 2.4%/mmHg (+/-0.4%), whereas the surface area-based DC was 4.1 %/mmHg (+/-0.1%). An increase in continuous flow was associated with a constant decrease in resistance, which correlated with the diameter-based DC (r=-0.8407, p=0.044) and the surface area-based DC (r=-0.8986, p=0.028). In contrast to the Linehan et al. equation, our results showed constant or even decreasing pressure as flow increased. Using a model of continuous pulmonary flow induced by an RV assist system, pulmonary pressure could not be predicted based on the flow using the Linehan et al. equation. Measurements of distensibility based on the diameter of the PA were inversely correlated with the resistance.
Mezi důležitou součást fyzikálního vyšetření dítěte patří zhodnocení pulzace periferních arterií a prokrvení periferie. Nezbytné je zároveň porovnání charakteru amplitudy pulsu na horních končetinách (palpací brachiálních, ev. radiálních arterií) a na dolních končetinách (palpací femorálních arterií). Při oslabení či opoždění pulsace na femorálních arteriích, pozorované v novorozeneckém či časném kojeneckém věku, musí být na prvním místě vyloučena srdeční vada – koarktace aorty. Absence pulsace femorálních arterií mohou zapříčinit i další patologie, ke kterým řadíme vrozené cévní malformace aortoiliacké oblasti, útlak cév extravaskulární masou (tumorem, cystou) a trombózy.
The assessment of peripheral arterial pulsation and peripheral perfusion is an important part of physical examination in infants. Itis also necessary to compare the character of the pulse amplitude on the upper limbs (palpation of the brachial or radial arteries)and on the lower limbs (palpation of the femoral arteries). If the pulsation of femoral arteries is weakened or delayed in neonatalperiod or in early infancy, a heart defect – coarctation of the aorta – has to be ruled out first. The absence of femoral artery pulsationmay also be caused by other pathologies, including congenital vascular malformations in the aortoiliac region, compressionof blood vessels by an extravascular mass (tumour, cyst) and thrombosis.
- MeSH
- arterie diagnostické zobrazování MeSH
- diferenciální diagnóza MeSH
- heparin aplikace a dávkování MeSH
- lidé MeSH
- novorozenec MeSH
- průchodnost cév * MeSH
- pulzatilní průtok * fyziologie MeSH
- trombolytická terapie MeSH
- trombóza diagnostické zobrazování etiologie terapie MeSH
- Check Tag
- lidé MeSH
- mužské pohlaví MeSH
- novorozenec MeSH
- Publikační typ
- kazuistiky MeSH
- MeSH
- arteria femoralis abnormality patofyziologie MeSH
- dítě MeSH
- koarktace aorty diagnóza MeSH
- lidé MeSH
- novorozenec MeSH
- pulzatilní průtok fyziologie MeSH
- trombóza * diagnóza terapie MeSH
- výsledek terapie MeSH
- Check Tag
- dítě MeSH
- lidé MeSH
- mužské pohlaví MeSH
- novorozenec MeSH
- Publikační typ
- kazuistiky MeSH
INTRODUCTION: Veno-arterial extracorporeal life support (ECLS) is increasingly being used to treat rapidly progressing or severe cardiogenic shock. However, it has been repeatedly shown that increased afterload associated with ECLS significantly diminishes left ventricular (LV) performance. The objective of the present study was to compare LV function and coronary flow during standard continuous-flow ECLS support and electrocardiogram (ECG)-synchronized pulsatile ECLS flow in a porcine model of cardiogenic shock. METHODS: Sixteen female swine (mean body weight 45 kg) underwent ECLS implantation under general anesthesia and artificial ventilation. Subsequently, acute cardiogenic shock, with documented signs of tissue hypoperfusion, was induced by initiating global myocardial hypoxia. Hemodynamic cardiac performance variables and coronary flow were then measured at different rates of continuous or pulsatile ECLS flow (ranging from 1 L/min to 4 L/min) using arterial and venous catheters, a pulmonary artery catheter, an LV pressure-volume loop catheter, and a Doppler coronary guide-wire. RESULTS: Myocardial hypoxia resulted in declines in mean cardiac output to 1.7±0.7 L/min, systolic blood pressure to 64±22 mmHg, and LV ejection fraction (LVEF) to 22±7%. Synchronized pulsatile flow was associated with a significant reduction in LV end-systolic volume by 6.2 mL (6.7%), an increase in LV stroke volume by 5.0 mL (17.4%), higher LVEF by 4.5% (18.8% relative), cardiac output by 0.37 L/min (17.1%), and mean arterial pressure by 3.0 mmHg (5.5%) when compared with continuous ECLS flow at all ECLS flow rates (P<0.05). At selected ECLS flow rates, pulsatile flow also reduced LV end-diastolic pressure, end-diastolic volume, and systolic pressure. ECG-synchronized pulsatile flow was also associated with significantly increased (7% to 22%) coronary flow at all ECLS flow rates. CONCLUSION: ECG-synchronized pulsatile ECLS flow preserved LV function and coronary flow compared with standard continuous-flow ECLS in a porcine model of cardiogenic shock.
- MeSH
- elektrokardiografie metody MeSH
- funkce levé komory srdeční fyziologie MeSH
- hemodynamika MeSH
- kardiogenní šok patologie patofyziologie terapie MeSH
- koronární cévy patofyziologie MeSH
- koronární cirkulace fyziologie MeSH
- mimotělní membránová oxygenace metody MeSH
- modely nemocí na zvířatech * MeSH
- prasata * MeSH
- pulzatilní průtok fyziologie MeSH
- resuscitační péče metody MeSH
- zvířata MeSH
- Check Tag
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Cardiovascular (CV) disease is the primary cause of death in diabetic patients and one of the explanations may be increased arterial stiffness. Arterial stiffness assessment using pulse wave analysis, is a predictive factor of CV events. The aim of this paper is to review the current knowledge of relations between diabetes mellitus and pulse wave analysis. A MEDLINE search was performed to retrieve both original and review articles addressing the relations and influences on arterial stiffness in diabetics. Pulse wave analysis is considered as a gold standard in CV risk evaluation for patients at risk, especially diabetics. Arterial stiffness assessment may be helpful for choosing more aggressive diagnostic and therapeutic strategies, particularly in younger patients to reduce the incidence of CV disease in these patients.
- MeSH
- analýza pulzové vlny * MeSH
- diabetes mellitus 2. typu komplikace patofyziologie MeSH
- diabetické angiopatie diagnóza etiologie patofyziologie MeSH
- lidé MeSH
- prediktivní hodnota testů MeSH
- pulzatilní průtok fyziologie MeSH
- rizikové faktory MeSH
- tuhost cévní stěny fyziologie MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- přehledy MeSH
The effect of pulsatile blood flow on microcirculation during extracorporeal cardiopulmonary resuscitation (ECPR) is not elucidated; therefore, we designed an observational study comparing sublingual microcirculation in patients with refractory cardiac arrest (CA) with spontaneously pulsatile or low/nonpulsatile blood flow after treatment with ECPR. Microcirculation was assessed with Sidestream Dark Field technology in 12 patients with CA who were treated with ECPR and 12 healthy control subjects. Microcirculatory images were analyzed offline in a blinded fashion, and consensual parameters were determined for the vessels ≤20 μm. The patients' data, including actual hemodynamic parameters, were documented. Pulsatile blood flow was defined by a pulse pressure (PP) ≥ 15 mm Hg. Compared with the healthy volunteers, the patients who were treated with ECPR exhibited a significantly lower proportion of perfused capillaries (PPC); other microcirculatory parameters did not differ. The groups of patients with pulsatile (n = 7) versus low/nonpulsatile (n = 5) blood flow did not differ in regards to the collected data and hemodynamic variables (except for the PP and ejection fraction of the left ventricle) as well as microcirculatory parameters. In conclusion, microcirculation appeared to be effectively supported by ECPR in our group of patients with CA with the exception of the PPC. We found only nonsignificant contribution of spontaneous pulsatility to extracorporeal membrane oxygenation-generated microcirculatory blood flow.
- MeSH
- dospělí MeSH
- kardiopulmonální resuscitace metody MeSH
- lidé středního věku MeSH
- lidé MeSH
- mikrocirkulace fyziologie MeSH
- mimotělní membránová oxygenace metody MeSH
- pilotní projekty MeSH
- pulzatilní průtok fyziologie MeSH
- senioři MeSH
- srdeční zástava terapie MeSH
- Check Tag
- dospělí MeSH
- lidé středního věku MeSH
- lidé MeSH
- mužské pohlaví MeSH
- senioři MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
BACKGROUP AND PURPOSE: There are limited data regarding the diagnostic yield of transcranial color-coded Doppler (TCCD) in acute encephalitis. We present our preliminary observations of consecutive ultrasound evaluations in 2 patients with acute encephalitis and we review the possible diagnostic role of TCCD in such cases. METHODS: We describe two cases of acute encephalitis that presented with aphasia and confusion and underwent repeat TCCD evaluation at baseline and after 48 hours in both patients. We also critically review the current literature regarding potential TCCD applications in acute central nervous system infections. RESULTS: Serial TCCD evaluations revealed the following triad of abnormal findings in both patients: (i) elevated pulsatility index (PI) in the left middle cerebral artery (M1 MCA) at baseline (>1.2), (ii) increased PI in left M1 MCA by >25% in comparison to right M1 MCA, and (iii) decrease in PI in left M1 MCA by >25% at the follow-up evaluation at 48 hours. The decrease in PI in left M1 MCA coincided with symptom improvement in both patients. DISCUSSION: The focal transient increase in left M1 MCA PI may be attributed to focally increased intracranial pressure or peripheral vasospasm of distal left MCA branches. Since there are limited reports in the literature concerning TCCD evaluation of patients with central nervous system infections, our preliminary findings require independent confirmation in a larger series of patients.
- MeSH
- akutní febrilní encefalopatie diagnostické zobrazování MeSH
- arteria cerebri media diagnostické zobrazování MeSH
- herpeszosterová encefalitida diagnostické zobrazování MeSH
- lidé MeSH
- listeriová meningitida diagnostické zobrazování MeSH
- magnetická rezonanční tomografie MeSH
- následné studie MeSH
- počítačová rentgenová tomografie MeSH
- předpověď MeSH
- pulzatilní průtok fyziologie MeSH
- senioři nad 80 let MeSH
- senioři MeSH
- ultrasonografie dopplerovská barevná trendy MeSH
- ultrasonografie dopplerovská transkraniální trendy MeSH
- Check Tag
- lidé MeSH
- senioři nad 80 let MeSH
- senioři MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
- kazuistiky MeSH
- přehledy MeSH
