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
- Optic Disk * MeSH
- Humans MeSH
- Intraocular Pressure MeSH
- Pulsatile Flow physiology MeSH
- Heart Rate MeSH
- Retinal Vein * physiology MeSH
- Check Tag
- Humans MeSH
- Publication type
- Journal Article 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
- Circle of Willis physiology MeSH
- Equipment Design * MeSH
- Humans MeSH
- Cerebrovascular Circulation physiology MeSH
- Orbit * blood supply MeSH
- Plethysmography instrumentation standards MeSH
- Pulsatile Flow physiology MeSH
- Regional Blood Flow physiology MeSH
- Reproducibility of Results MeSH
- Check Tag
- Humans MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't 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
- Arteries physiopathology MeSH
- Assisted Circulation instrumentation methods MeSH
- Diagnostic Techniques, Cardiovascular MeSH
- Blood Pressure physiology MeSH
- Middle Aged MeSH
- Humans MeSH
- Heart-Assist Devices * MeSH
- Pulse methods MeSH
- Pulsatile Flow physiology MeSH
- Reproducibility of Results MeSH
- Aged MeSH
- Heart Failure * physiopathology therapy MeSH
- Check Tag
- Middle Aged MeSH
- Humans MeSH
- Male MeSH
- Aged MeSH
- Female MeSH
- Publication type
- Journal Article 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
- Arteries diagnostic imaging MeSH
- Diagnosis, Differential MeSH
- Heparin administration & dosage MeSH
- Humans MeSH
- Infant, Newborn MeSH
- Vascular Patency * MeSH
- Pulsatile Flow * physiology MeSH
- Thrombolytic Therapy MeSH
- Thrombosis diagnostic imaging etiology therapy MeSH
- Check Tag
- Humans MeSH
- Male MeSH
- Infant, Newborn MeSH
- Publication type
- Case Reports MeSH
- MeSH
- Femoral Artery abnormalities physiopathology MeSH
- Child MeSH
- Aortic Coarctation diagnosis MeSH
- Humans MeSH
- Infant, Newborn MeSH
- Pulsatile Flow physiology MeSH
- Thrombosis * diagnosis therapy MeSH
- Treatment Outcome MeSH
- Check Tag
- Child MeSH
- Humans MeSH
- Male MeSH
- Infant, Newborn MeSH
- Publication type
- Case Reports 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
- Electrocardiography methods MeSH
- Ventricular Function, Left physiology MeSH
- Hemodynamics MeSH
- Shock, Cardiogenic pathology physiopathology therapy MeSH
- Coronary Vessels physiopathology MeSH
- Coronary Circulation physiology MeSH
- Extracorporeal Membrane Oxygenation methods MeSH
- Disease Models, Animal * MeSH
- Swine * MeSH
- Pulsatile Flow physiology MeSH
- Life Support Care methods MeSH
- Animals MeSH
- Check Tag
- Female MeSH
- Animals MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't 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
- Pulse Wave Analysis * MeSH
- Diabetes Mellitus, Type 2 complications physiopathology MeSH
- Diabetic Angiopathies diagnosis etiology physiopathology MeSH
- Humans MeSH
- Predictive Value of Tests MeSH
- Pulsatile Flow physiology MeSH
- Risk Factors MeSH
- Vascular Stiffness physiology MeSH
- Check Tag
- Humans MeSH
- Publication type
- Journal Article MeSH
- Review 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
- Adult MeSH
- Cardiopulmonary Resuscitation methods MeSH
- Middle Aged MeSH
- Humans MeSH
- Microcirculation physiology MeSH
- Extracorporeal Membrane Oxygenation methods MeSH
- Pilot Projects MeSH
- Pulsatile Flow physiology MeSH
- Aged MeSH
- Heart Arrest therapy MeSH
- Check Tag
- Adult MeSH
- Middle Aged MeSH
- Humans MeSH
- Male MeSH
- Aged MeSH
- Female MeSH
- Publication type
- Journal Article 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
- Acute Febrile Encephalopathy diagnostic imaging MeSH
- Middle Cerebral Artery diagnostic imaging MeSH
- Encephalitis, Varicella Zoster diagnostic imaging MeSH
- Humans MeSH
- Meningitis, Listeria diagnostic imaging MeSH
- Magnetic Resonance Imaging MeSH
- Follow-Up Studies MeSH
- Tomography, X-Ray Computed MeSH
- Forecasting MeSH
- Pulsatile Flow physiology MeSH
- Aged, 80 and over MeSH
- Aged MeSH
- Ultrasonography, Doppler, Color trends MeSH
- Ultrasonography, Doppler, Transcranial trends MeSH
- Check Tag
- Humans MeSH
- Aged, 80 and over MeSH
- Aged MeSH
- Female MeSH
- Publication type
- Journal Article MeSH
- Case Reports MeSH
- Review MeSH
