Determination Of Blood Oxygen Saturation Research Articles

Clinical significance of echocardiographic signs of right heart dysfunction in patients with chronic heart failure with preserved left ventricular ejection fraction

Aim: To analyze the features of clinical signs, quality of life and psycho-emotional state in patients with heart failure with preserved left ventricular ejection fraction (HFpEF) and non-obstructive atherosclerosis of the coronary arteries, depending on the presence of echocardiographic criteria for dysfunction of the right heart.Material and Methods. Patients underwent an extended protocol of echocardiography with an assessment of the structure and function of the right heart; ultrasound examination of the lungs with the determination of the number of B-lines; a six-minute walk test, a test for the presence of a symptom of bendopnea with the determination of blood oxygen saturation (SpO2) before and during the test. In addition, quality of life was assessed using the Minnesota questionnaire and the SF-36 questionnaire (The Short Form-36); the psycho-emotional state of patients was analyzed according to the HADS (Hospital Anxiety and Depression Scale), the level of adherence to treatment was analyzed according to the Morisky – Green questionnaire. Patients were divided into two groups depending on signs of right heart dysfunction: Tei index more than 0.54, tricuspid annulus systolic excursion (TAPSE) less than 17 mm, tricuspid annulus systolic velocity (RV S’) less than 9,5 cm/sec.Results. Echocardiographic signs of right heart dysfunction in patients with HFpEF was associated with lower quality of life indicators according to the SF-36 questionnaire, in particular, general health status (p = 0.008) and role limitations due to emotional problems (p = 0.03). During the bendopnea test (p = 0.04), the majority of patients with signs of dysfunction of the right heart (66.7%) had a decrease in SpO2, while in the comparison group the proportion of such patients was 36.7% (p = 0.04). The psycho-emotional state according to the HADS scale and adherence to treatment did not differ in both groups (p > 0.05). The frequency of detection of B-lines according to lung ultrasound was also comparable.

CHANGES IN VENTILATION FUNCTION AND RESERVES OF GAS EXCHANGE IN CHILDREN WITH ACUTE BRONCHITIS

Among the diseases of the lower part of respiratory system in children, acute bronchitis dominates, often with obstructive syndrome and ventilation disorders. To assess the severity of the obstructive syndrome spirometry is used, which is the "gold standard" for this purpose. It combines two groups of tests: spirography – graphical recording of changes in lung volumes during respiratory movements and pneumotachography – graphical recording of the air flow velocity during tidal and forced breathing. Among modern methods, non-invasive determination of blood oxygen saturation with pulse oximetry is becoming increasingly popular. The combined use of spirometry and pulse oximetry makes it possible to determine accurately the state and reserves of the cardiorespiratory system in a wide range of pathological changes. Objective. To learn the features of ventilation function and gas exchange in children with acute bronchitis. Materials and methods. The paper analyzes the results of a survey of 59 children with acute bronchitis. Patients underwent a clinical examination, spirometry, pulse oximetry; breath-hold tests were performed. The results of spirometry and pulse oximetry were compared with the data of clinically healthy children (23 children). Results. In children, the severity of bronchitis was moderate according to the BSS-7.79 ± 0.19 points, 30 patients had symptoms of obstructive syndrome. Spirometry recorded a decrease in forced respiratory volumes, peak forced expiratory flow and inspiratory flow. Pulse oximetry showed a relatively lower level of oxygen saturation in patients, which worsened during breath-hold tests. The obtained results indicate impaired ventilation and gas exchange in children with bronchitis, even with a mild course of the disease, especially in the presence of obstructive phenomena. Compensatory mechanisms for maintaining blood saturation based mainly on an increase in systemic blood flow due to an increase in heart rate. Conclusions. In acute bronchitis in children, ventilation and gas exchange rates decrease, even in those patients with a mild course. Compensatory mechanisms for maintaining blood saturation are based mainly on increased systemic blood flow due to increased heart rate.

Functional Imaging of the Ocular Fundus Using an 8-Band Retinal Multispectral Imaging System

Application of functional imaging in ophthalmology requires efficient imaging techniques that can detect and quantify chromophores to visualise processes in vivo. The aim of the present study was to develop and evaluate a fast and affordable imaging system. We describe an eight-band retinal multispectral imaging (MSI) system and compare it with a hyperspectral imaging (HSI) device. Determination of blood oxygen saturation was studied as proof of principle. Reflectance of incident light is measured as 1/absorbance at different wavelengths between 440 nm and 580 nm. Both devices have incorporated optical bandpass filters in a mydriatic fundus camera. The MSI system scans the retina at eight pre-defined wavelengths specific for the spectrum of haemoglobin. The HSI system acquires a full scan from 480 to 720 nm in 5 nm steps. A simple assessment of the ratio between the absorbance peaks of oxygenated haemoglobin (HbO2) and reduced haemoglobin (HbR) was not suitable for generating validated oxygenation maps of the retina. However, a correction algorithm that compares the measured reflectance with reflectance spectra of fully oxygenated and fully deoxygenated blood allowed our MSI setup to estimate relative oxygen saturation at higher levels, but underestimated relative oxygen saturation at lower levels. The MSI device generated better quality images than the HSI device. It allows customisation with filter sets optimised for other chromophores of interest, and augmented with extrinsic contrast imaging agents, it has the potential for a wider range of ophthalmic molecular imaging applications.

CLINICAL AND FUNCTIONAL CHARACTERISTICS OF CHRONIC OBSTRUCTIVE PULMONARY DISEASE IN CONDITIONS OF EXPOSURE TO INDUSTRIAL AEROSOLS

The aim is to study the clinical and functional characteristics and indicators of blood gas composition in workers with chronic obstructive pulmonary disease (COPD) exposed to the effects of industrial aerosols (IA). Material and Methods. The study included 132 patients with a diagnosis of COPD, stage I, category C; 68 were working in conditions of exposure to IA toxico-chemical action, and 64 people had COPD (comparison group which never worked in conditions of exposure to IA). Patients in both groups were divided into 2 subgroups: subgroup 1 — the duration of exposure to IA did not exceed 10 years, 2 — more than 10 years. Spirography was carried out on the device Care Fusion UK 232 Ltd. carbon monoxide (CO) content in exhaled air was determined using gas analyzer CareFusion Smoke check. Determination of blood oxygen saturation was carried out using pulse oximetry method. The content of the partial pressure of carbon dioxide (pCO2 ) and oxygen (pO2 ) in the venous blood were studied by Astrup method. Results. Most smokers were identified in the group exposed to long-term IA. The lowest values of forced expiratory volume in one second, vital capacity and Tiffeneau index were observed among persons exposed to IA differed significantly (p<0.05) from the control group. The highest values of CO and pCO2 , and pO2 were lowest in the group of patients with COPD in the combination of IA and in smokers. Conclusion. The high frequency and long duration of smoking was found out among the workers exposed to IA. Florid violations of wheeze were detected in individuals exposed to IA. As duration of the production contact with IA increasing, more serious violations of gas exchange are formed in patients with COPD. Keywords: chronic obstructive pulmonary disease, pollutants, industrial enterprise, function of external respiration, dyspnea><0.05) from the control group. The highest values of CO and pCO2 , and pO2 were lowest in the group of patients with COPD in the combination of IA and in smokers. Conclusion. The high frequency and long duration of smoking was found out among the workers exposed to IA. Florid violations of wheeze were detected in individuals exposed to IA. As duration of the production contact with IA increasing, more serious violations of gas exchange are formed in patients with COPD.

Noninvasive photoacoustic measurement of absorption coefficient using internal light irradiation of cylindrical diffusing fiber

Absorption coefficient of biological tissue is an important parameter in biomedicine, but its determination remains a challenge. In this paper, we propose a method using focusing photoacoustic imaging technique and internal light irradiation of cylindrical diffusing fiber (CDF) to quantify the target optical absorption coefficient. Absorption coefficients for ink absorbers are firstly determined through photoacoustic and spectrophotometric measurements at the same excitation, which demonstrates the feasibility of this method. Also, the optical absorption coefficients of ink absorbers with several concentrations are measured. Finally, the two-dimensional scanning photoacoustic image is obtained. Optical absorption coefficient measurement and simultaneous photoacoustic imaging of absorber non-invasively are the typical characteristics of the method. This method can play a significant role for non-invasive determination of blood oxygen saturation, the absorption-based imaging and therapy.

Optimal wavelengths for optoacoustic measurements of blood oxygen saturation in biological tissues.

The non-invasive measurement of blood oxygen saturation in blood vessels is a promising clinical application of optoacoustic imaging. Nevertheless, precise optoacoustic measurements of blood oxygen saturation are limited because of the complexities of calculating the spatial distribution of the optical fluence. In the paper error in the determination of blood oxygen saturation, associated with the use of approximate methods of optical fluence evaluation within the blood vessel, was investigated for optoacoustic measurements at two wavelengths. The method takes into account both acoustic pressure noise and the error in determined values of the optical scattering and absorption coefficients used for the calculation of the fluence. It is shown that, in conditions of an unknown (or partially known) spatial distribution of fluence at depths of 2 to 8 mm, minimal error in the determination of blood oxygen saturation is achieved at wavelengths of 658 ± 40 nm and 1069 ± 40 nm.

Measurement technique for the determination of blood oxygen saturation

A new optical measurement technique based on spectral scanning is described for the determination of oxygen saturation of whole blood. The principles of this technique are outlined, together with a calibration procedure used to test its feasibility in vitro. The preliminary results show that the accuracy of the new technique is of the order ± 2% over the full range of oxygen saturation. This degree of accuracy is comparable with commercial CO-oximeters.

Wavelength dependency of the spectrophotometric determination of blood oxygen saturation

Wavelength dependency of the spectrophotometric determination of blood oxygen saturation

A saline conductivity method for detection of cardiac shunts by indicator-dilution technic.

A new method for cardiovascular shunt detection is described using the indicator-dilution principle applied to blood conductivity changes produced by 5 per cent saline. It possesses these distinct advantages over the Evans blue technic: (1) an unlimited number of determinations can be made without an increasing blood dye background or bluish discoloration of the patient, (2) oximetric determination of blood oxygen saturation is not interferred with, and (3) a simple modification of the carrier amplifiers of commonly used recording systems supplies most of the necessary instrumentation.

The microspectrophotometric determination of blood oxygen saturation in infants and children

Summary A rapid and reasonably accurate(within 5 per cent) method for the microspectrophotometric determination of blood oxygen saturation in infants and children is presented. A technique for blood collection simply performed with a minimum of disturbance and cumbersome impedimenta is described.