Saturation Measurements Research Articles

CMOS Pulse Oximeter

Abstract: This paper presents the design and implementation of a non-invasive pulse oximeter based on Complementary MetalOxide-Semiconductor (CMOS) technology, aimed at enhancing the accuracy and accessibility of blood oxygen saturation measurements. Pulse oximetry is a critical tool in clinical and personal health monitoring, providing vital information about respiratory function. The integration of CMOS technology allows for miniaturization and energy efficiency, facilitating the development of compact, wearable devices capable of continuous monitoring. The proposed system utilizes advanced signal processing techniques, including lock-in detection and dual-wavelength illumination, to improve the reliability of photoplethysmographic (PPG) signal acquisition under various conditions. Experimental validation demonstrates the device's capability to deliver accurate SpO2 readings even in the presence of motion artifacts and ambient light interference. Furthermore, the calibration methods employed ensure that measurements are consistent and precise across different users. By leveraging the advantages of CMOS technology, this study not only highlights the potential for improved patient comfort and compliance but also opens new avenues for the application of pulse oximetry in diverse environments. The findings underscore the effectiveness of CMOS-based pulse oximeters in advancing non-invasive health monitoring solutions, ultimately contributing to enhanced patient care and outcomes.

Low oxygen saturation and discordant arterial blood gas measures have diagnosed a case of hemoglobinopathy

Pulse oximeter is a simple non-invasive equipment used to determine patient’s arterial blood oxygen saturation (SpO2). However, in some people, arterial blood gas measures (SaO2) are normal and low SpO2 values are related to hemoglobin variant rather than cardiac or pulmonary illnesses. Aim. We present a case of thalassemia that manifested with low SpO2 and discordant SaO2. Conclusion. When examining a patient with an unusually low SpO2, the differential diagnosis of a suspected hemoglobin variant should be investigated. Establishing an accurate diagnosis as soon as possible may help avoid unnecessary tests.

Exploring comparative heterogeneity management for precise water saturation assessment in carbonate formations: Dean-Stark measurements and beyond

Accurate determination of water saturation is a critical aspect of reservoir characterization and development potential of a hydrocarbon field. The inherent heterogeneity in carbonate reservoirs significantly influences the Archie equation coefficients and, consequently, water saturation calculations. In this study, 160 direct core sample water saturation measurements using the Dean-Stark method have been used. The primary goal was to identify the most suitable reservoir heterogeneity management approach for water saturation calculation. The research focuses on the Dalan and Kangan formations (equivalent to Khuff Formation), known as some of the most hydrocarbon-rich (gas) reservoirs globally, located in the western part of the Persian Gulf. To manage reservoir heterogeneity, we employed various techniques, including Winland R35, flow zone indicator, Lucia, pore types, and electrofacies, utilizing porosity and permeability core data, thin section studies, and well-logging data to classify the studied intervals into more homogeneous categories. Subsequently, we measured Archie parameters and, for the first time, water saturations derived from Dean-Stark measurements were compared with Archie saturations from various heterogeneity management methods. Additionally, the influence of geological and petrophysical parameters on the accuracy of water saturation calculations in different rock types is discussed. Our results highlighted the significance of geometrical attributes of pore types, pore throat radius, and permeability as key factors affecting the precision of water saturation calculations. Moreover, our investigation revealed that Lucia's rock typing methodology exerted a substantial influence on the control of permeability and the distribution of water saturation within the reservoir. Our analysis revealed that the electrofacies method provided the most precise estimates for water saturation, with a mean difference of 0.07 (v/v) units compared to the Dean-Stark method. Subsequently, the accuracy of predicted water saturation in rock types determined by the Lucia method, with a mean error of 0.09 (v/v), ranked second among the rock typing methods. Winland R35 and flow zone indicator methods exhibited the highest uncertainty in water saturation estimation, with mean differences of 0.23 and 0.21 (v/v), respectively, compared to the Dean-Stark method.

Oxygen saturation measurement in cyanotic heart disease with the Apple watch.

Accurate measurement of transcutaneous oxygen saturation is important for the assessment of cyanosis in CHD. Aim of this study was the evaluation of a supplementary transcutaneous oxygen saturation measurement with an Apple watch® in children with cyanotic heart disease. During a six-minute walk test, measurement of transcutaneous oxygen saturation was performed simultaneously with an Oximeter (Nellcor, Medtronic, USA) and an Apple watch® Series 7 (Apple inc, USA) in 36 children with cyanotic heart disease. Median age was 9.2 (IQR 5.7-13.8) years. Transcutaneous oxygen saturation measurement with the Apple watch® was possible in 35/36 and 34/36 subjects before and after six-minute walk test. Children, in whom Apple watch® measurement was not possible, had a transcutaneous oxygen saturation < 85% on oximeter. Before six-minute walk test, median transcutaneous oxygen saturation was 93 (IQR 91-97) % measured by oximeter and 95 (IQR 93-96) % by the Apple watch®. After a median walking distance of 437 (IQR 360-487) m, transcutaneous oxygen saturation dropped to 92 (IQR 88-95, p < 0.001) % by oximeter and to 94 (IQR 90-96, p = 0.013) % measured with the Apple watch®. In children with mild cyanosis measurement of transcutaneous oxygen saturation with an Apple watch® showed only valid results if transcutaneous oxygen saturation was > 85%, with higher values being measured with the smart watch. In children with moderate or severe cyanosis transcutaneous oxygen saturation, measurement with the Apple watch® was not reliable and cannot be recommended to monitor oxygen saturation at home.

A retrospective evaluation of SwePEWS use in paediatric patients with COVID-19 and RSV infection.

As early detection of deterioration is a challenge in children, the Swedish Paediatric Early Warning Score (SwePEWS) is used to systematically assess paediatric patients' clinical state. Here, we aimed to evaluate the use and predictive ability of SwePEWS. Electronic health records of paediatric patients admitted due to respiratory syncytial virus infection or COVID-19 were reviewed retrospectively. Registered vital signs were compared to the assigned SwePEWS score and monitored vital sign values to identify discrepancies. Additionally, SwePEWS's ability to predict transfer to the paediatric intensive care unit (PICU) was assessed. Among 1374 SwePEWS assessments, one-third were either incomplete or contained errors. Incomplete SwePEWS assessments were more frequent during night-time. Single measurements of oxygen saturation presented lower values compared to average saturation from continuous monitoring. SwePEWS's ability to predict PICU transfer was low. There was a surprisingly high occurrence of underestimated SwePEWS scores. This study provides new insights into pitfalls when developing and implementing paediatric early warning scores for systematic re-evaluations in paediatric patients.

Implementation of an algorithm for predicting exacerbations in telemonitoring: A multimethod study of patients’ and clinicians’ experiences

BackgroundPrediction algorithms may improve the ability of telehealth solutions to assess the risk of future exacerbations in patients with chronic obstructive pulmonary disease. Learning from patients’ and clinicians’ evaluations and experiences about the use of such algorithms is essential to evaluate its potential and examine factors that could potentially influence the implementation and sustained use. ObjectiveTo investigate the patients’ and clinicians’ perceptions and satisfaction with an algorithm for predicting exacerbations in patients with chronic obstructive pulmonary disease. DesignMultimethod study. SettingThree community nursing sites in Aalborg Municipality, Denmark. ParticipantsOne hundred and eleven adults with chronic obstructive pulmonary disease and four clinicians (three nurses and one physiotherapist) specialized in telehealth monitoring of the disease. MethodsThe study was performed from November 2021 to November 2022 alongside a clinical trial in which a prediction algorithm was integrated into an existing telehealth system. The patients’ perspectives were investigated using a self-constructed questionnaire. The clinicians’ perspective was explored using semistructured individual interviews. ResultsMost patients (84.0%–90.8%) were satisfied with the algorithm and the additional measurements required by the algorithm. Approximately 71.7%–75.9% found that the algorithm could be a useful tool for disease assessment. Patients elaborated that they could see an exacerbation prevention potential in the algorithm. Patients trusted the algorithm and found an increased sense of security. The clinicians showed a positive response toward the algorithm and its user-friendliness. However, they were concerned that the additional measurements could be too demanding for some patients and questioned the accuracy of the measurements. Some felt that the algorithm could risk being time-consuming and harm the overall assessment of the individual patient. They expressed a need for continuous information about the algorithm to understand its functions and alarms. ConclusionsOptimal use of the algorithm would require that patients perform additional pulse and oxygen saturation measurements. Furthermore, it will require in-depth insight among clinicians regarding the algorithm's functions and alarms. RegistrationThe study was performed alongside a clinical trial, which was first registered September 9, 2021, at clinicaltrials.gov (registration number NCT05218525). Date of first recruitment was September 28, 2021.

Exploring the impact and influence of melanin on frequency-domain near-infrared spectroscopy measurements.

Near-infrared spectroscopy (NIRS) is a non-invasive optical method that measures changes in hemoglobin concentration and oxygenation. The measured light intensity is susceptible to reduced signal quality due to the presence of melanin. We quantify the influence of melanin concentration on NIRS measurements taken with a frequency-domain near-infrared spectroscopy system using 690 and 830nm. Using a forehead NIRS probe, we measured 35 healthy participants and investigated the correlation between melanin concentration indices, which were determined using a colorimeter, and several key metrics from the NIRS signal. These metrics include signal-to-noise ratio (SNR), two measurements of oxygen saturation (arterial oxygen saturation, , and tissue oxygen saturation, ), and optical properties represented by the absorption coefficient ( ) and the reduced scattering coefficient ( ). We found a significant negative correlation between the melanin index and the SNR estimated in oxy-hemoglobin signals ( , ) and levels ( , ). However, no significant changes were observed in the optical properties and ( , ). We found that estimated SNR and values show a significant decline and dependence on the melanin index, whereas and optical properties do not show any correlation with the melanin index.

Deep learning based measurement accuracy improvement of high dynamic range objects in fringe projection profilometry

One of the key factors affecting the accuracy of three-dimensional (3D) measurement in fringe projection profilometry (FPP) is the phase retrieve accuracy. In the 3D measurement of high dynamic range (HDR) objects, fringe saturation and/or low contrast are difficult to avoid. A greater number of fringe images are needed for 3D measurement of HDR objects by traditional methods, which is unfavorable for the measurement of moving objects. In this paper, what we believe to be a new method to solve the phase demodulation problem of HDR objects using deep learning is proposed. In this method, a “many-to-one” mapping relationship is established using an improved UNet deep neural network. In addition, in order to obtain more saturated fringe information, π-shifted binary fringes were also used. This allows us to retrieve the wrapped phase of HDR objects quickly and accurately. Experimental results demonstrate the effectiveness and reliability of the proposed method.

Usefulness of bilateral cerebral regional oxygen saturation measurements in determining selective cerebral perfusion flow rate in a pediatric patient with aortic arch stenosis: a case report

BackgroundWe report a pediatric case where bilateral regional oxygen saturation (rSO2) measurements were useful in determining the selective cerebral perfusion (SCP) flow rate.Case presentationA 9-year-old Japanese boy, 128 cm tall and weighing 25.6 kg, was scheduled for aortic arch reconstruction due to a 90–100 mmHg pressure gradient. Pediatric-sized oximetry sensors were attached to the bilateral forehead area. The rSO2 levels were 70–80% on the right and 80–90% on the left during cardiopulmonary bypass. Immediately following deep hypothermic circulatory arrest with the body temperature cooled to 25 °C, SCP was initiated from the right brachiocephalic artery at 10 mL/kg/min. As the rSO2 decreased steeply to 43–45% on the right and to 32–38% on the left, the SCP flow was increased to 15 mL/kg/min. The right rSO2 increased promptly to 50–60%, but the left rSO2 remained at 30–40%. After the SCP flow was increased to 20 mL/kg/min, bilateral rSO2 levels of 50–60% were obtained, and the SCP flow rate was maintained. The patient was transferred to the ICU postoperatively and extubated on the second postoperative day with no neurological abnormalities.ConclusionsBilateral rSO2 measurements are essential even for a pediatric patient undergoing SCP, despite the limited forehead area.

Impact of non-invasive oxygen reserve index versus standard SpO2 monitoring on peripheral oxygen saturation during endotracheal intubation in the intensive care unit: Protocol for the randomized controlled trial NESOI2.

In critically ill patients, endotracheal intubation (ETI) is lifesaving but carries a high risk of adverse events, notably hypoxemia. Preoxygenation is performed before introducing the tube to increase the safe apnea time. Oxygenation is monitored by pulse oximeter measurement of peripheral oxygen saturation (SpO2). However, SpO2 is unreliable at the high oxygenation levels produced by preoxygenation and, in the event of desaturation, may not decrease sufficiently early to allow preventive measures. The oxygen reserve index (ORI) is a dimensionless parameter that can also be measured continuously by a fingertip monitor and reflects oxygenation in the moderate hyperoxia range. The ORI ranges from 0 to 1 when arterial oxygen saturation (PaO2) varies between 100 to 200 mmHg, as occurs during preoxygenation. No trial has assessed the potential effects of ORI monitoring to guide preoxygenation for ETI in unstable patients. We designed a multicenter, two-arm, parallel-group, randomized, superiority, open trial in 950 critically ill adults requiring ETI. The intervention consists in monitoring ORI values and using an ORI target for preoxygenation of at least 0.6 for at least 1 minute. In the control group, preoxygenation is guided by SpO2 values recorded by a standard pulse oximeter, according to the standard of care, the goal being to obtain 100% SpO2 during preoxygenation, which lasts at least 3 minutes. The standard-of-care ETI technique is used in both arms. Baseline parameters, rapid-sequence induction medications, ETI devices, and physiological data are recorded. The primary outcome is the lowest SpO2 value from laryngoscopy to 2 minutes after successful ETI. Secondary outcomes include cognitive function on day 28. Assuming a 10% standard deviation for the lowest SpO2 value in the control group, no missing data, and crossover of 5% of patients, with the bilateral alpha risk set at 0.05, including 950 patients will provide 85% power for detecting a 2% between-group absolute difference in the lowest SpO2 value. Should ORI monitoring with a target of ≥0.6 be found to increase the lowest SpO2 value during ETI, then this trial may change current practice regarding preoxygenation for ETI. Trial registration: Registered on ClinicalTrials.gov (NCT05867875) on April 27, 2023.

Investigation of a Camera-Based Contactless Pulse Oximeter with Time-Division Multiplex Illumination Applied on Piglets for Neonatological Applications.

(1) Objective: This study aims to lay a foundation for noncontact intensive care monitoring of premature babies. (2) Methods: Arterial oxygen saturation and heart rate were measured using a monochrome camera and time-division multiplex controlled lighting at three different wavelengths (660 nm, 810 nm and 940 nm) on a piglet model. (3) Results: Using this camera system and our newly designed algorithm for further analysis, the detection of a heartbeat and the calculation of oxygen saturation were evaluated. In motionless individuals, heartbeat and respiration were separated clearly during light breathing and with only minor intervention. In this case, the mean difference between noncontact and contact saturation measurements was 0.7% (RMSE = 3.8%, MAE = 2.93%). (4) Conclusions: The new sensor was proven effective under ideal animal experimental conditions. The results allow a systematic improvement for the further development of contactless vital sign monitoring systems. The results presented here are a major step towards the development of an incubator with noncontact sensor systems for use in the neonatal intensive care unit.

Methodology for Evaluating the Performance of a New Pulse Oximeter Model and Pulse Oximetry Algorithm in Neonates in a Clinical Trial (Exploratory Study)

While evaluating a new domestically produced pulse oximeter model in clinical practice, we discovered a lack of references in Russian-language publications on clinical trial methodologies to assess device reliability and performance.The aim of the study is to create a methodology for conducting a multicenter, prospective, cohort, nonrandomized, controlled clinical trial evaluating a domestic pulse oximeter.Methods. Measurements were performed on 20 preterm infants in the neonatal intensive care unit with a mean birth weight of 2340 [1250; 3125] g and a gestational age of 35 [30; 37] weeks using a new model pulse oximeter simultaneously with the reference monitor. Multiple oxygen saturation measurements of varying duration were taken alternately from the upper and lower limbs, and the number of false desaturation alarms was recorded. Pulse oximeter saturation data were evaluated for correlation with clinical findings.Results. Attachment of sensors to the infant's feet was found to be optimal in terms of ease of use, minimal artifact generation, and minimal interference with routine medical procedures and neonatal care. To reduce motion-induced artifacts and false alarms, the optimal period of SpO₂ monitoring to detect desaturations and bradycardia was determined to be 120 min. Due to the high variability of pulse rate (PR) and saturation in neonates, two-second intervals were determined to be optimal for comparing records from the two monitors. Matching of ECG HR and pulse oximeter PR was required to eliminate artifacts. A mathematical software model required for accelerated analysis of data collected from all sensors during the study was approved.Conclusion. The data analysis supported the proposed methodology for conducting a clinical trial to evaluate the performance and reliability of new pulse oximetry devices.

Predictive value of perfusion index (PI) on the discrepancy between oxygen saturation measurement via pulse oximetry and blood gas analysis

Predictive value of perfusion index (PI) on the discrepancy between oxygen saturation measurement via pulse oximetry and blood gas analysis

Open Access Data Repository and Common Data Model for Pulse Oximeter Performance Data.

The OpenOximetry Repository is a structured database storing clinical and lab pulse oximetry data, serving as a centralized repository and data model for pulse oximetry initiatives. It supports measurements of arterial oxygen saturation (SaO2) by arterial blood gas co-oximetry and pulse oximetry (SpO2), alongside processed and unprocessed photoplethysmography (PPG) data and other metadata. This includes skin color measurements, finger diameter, vital signs (e.g., arterial blood pressure, end-tidal carbon dioxide), and arterial blood gas parameters (e.g., acid-base balance, hemoglobin concentration). Data contributions are encouraged. All data, from desaturation studies to clinical trials, are collected prospectively to ensure accuracy. A common data model and standardized protocols for consistent archival and interpretation ensure consistent data archival and interpretation. The dataset aims to facilitate research on pulse oximeter performance across diverse human characteristics, addressing performance issues and promoting accurate pulse oximeters. The initial release includes controlled lab desaturation studies (CLDS), with ongoing updates planned as further data from clinical trials and CLDS become available.

History and Social Implications of the Pulse Oximeter.

The pulse oximeter is a portable, bedside tool that allows for the measurement of oxygen saturation in a patient's red blood cells. The technology is based on oxygenated and deoxygenated hemoglobin absorbing light at different wavelengths. The devicecalculates the ratio of oxygenated to deoxygenated hemoglobin in the blood, and an algorithm produces a percentage oxygen saturation value. Due to its portability and ease of use, it is a ubiquitous medical tool that is commonly used in medical practice.This paper reviews the history and evolution of this tool, and the scientific laws behind oximetry.It also introduces the importance of the pulse oximeter and its basic functions. In addition, the limitations of pulse oximetry are discussed, especially as they pertain to pigmented skin.

Research on dynamic blood oxygen saturation measurement based on motion noise reconstruction combined with convex combination least mean square adaptive filter

The performance of a pulse oximeter based on photoelectric detection is greatly affected by motion noise (MA) in the photoplethysmographic (PPG) signal. This paper presents an algorithm for detecting motion oxygen saturation, which reconstructs a motion noise reference signal using ensemble of complete adaptive noise and empirical mode decomposition combined with multi-scale permutation entropy, and eliminates MA in the PPG signal using a convex combination least mean square adaptive filters to calculate dynamic oxygen saturation. The test results show that, under simulated walking and jogging conditions, the mean absolute error (MAE) of oxygen saturation estimated by the proposed algorithm and the reference oxygen saturation are 0.05 and 0.07, respectively, with means absolute percentage error (MAPE) of 0.05% and 0.07%, respectively. The overall Pearson correlation coefficient reaches 0.971 2. The proposed scheme effectively reduces motion artifacts in the corrupted PPG signal and is expected to be applied in portable photoelectric pulse oximeters to improve the accuracy of dynamic oxygen saturation measurement.

Vital parameter monitoring in harsh environment by the MedSENS in-ear multisensor device

Accurate assessment of vital parameters is essential for diagnosis and triage of critically ill patients, but not always feasible in out-of-hospital settings due to the lack of suitable devices. We performed an extensive validation of a novel prototype in-ear device, which was proposed for the non-invasive, combined measurement of core body temperature (Tc), oxygen saturation (SpO2), and heart rate (HR) in harsh environments. A pilot study with randomized controlled design was conducted in the terraXcube environmental chamber. Participants were subsequently exposed to three 15 min test sessions at the controlled ambient temperatures of 20 °C, 5 °C, and − 10 °C, in randomized order. Vital parameters measured by the prototype were compared with Tc measurements from commercial esophageal (reference) and tympanic (comparator) probes and SpO2 and HR measurements from a finger pulse-oximeter (reference). Performance was assessed in terms of bias and Lin’s correlation coefficient (CCC) with respect to the reference measurements and analyzed with linear mixed models. Twenty-three participants (12 men, mean (SD) age, 35 (9) years) completed the experimental protocol. The mean Tc bias of the prototype ranged between − 0.39 and − 0.80 °C at ambient temperatures of 20 °C and 5 °C, and it reached − 1.38 °C only after 15 min of exposure to − 10 °C. CCC values ranged between 0.07 and 0.25. SpO2 and HR monitoring was feasible, although malfunctioning was observed in one third of the tests. SpO2 and HR bias did not show any significant dependence on environmental conditions, with values ranging from − 1.71 to − 0.52% for SpO2 and 1.12 bpm to 5.30 bpm for HR. High CCC values between 0.81 and 0.97 were observed for HR in all environmental conditions. This novel prototype device for measuring vital parameters in cold environments demonstrated reliability of Tc measurements and feasibility of SpO2 and HR monitoring. Through non-invasive and accurate monitoring of vital parameters from the ear canal our prototype may offer support in triage and treatment of critically ill patients in harsh out-of-hospital conditions.

Measuring the Electrolyte Distribution in Silver Gas Diffusion Electrodes during CO2 Electroreduction Using Operando Synchrotron Tomography

Electrochemical CO2 reduction (eCO2R) has emerged as a promising technology to support the shift away from fossil fuels in the chemical industry. When coupled with renewable energies it allows for an overall carbon-negative process, while enabling CO2 as a carbon source for the production of commodity chemicals. Efficient eCO2R requires gas diffusion electrodes (GDEs) that provide a large wetted surface area inside the porous system, while also preserving gaseous diffusion pathways for CO2 mass transport through their hydrophobicity. Under the high cathodic overpotential in eCO2R, electrowetting diminishes the hydrophobicity of the GDE and can lead to excessive flooding of the porous system [1]. This severely hinders the CO2 mass transport and thus gives rise to the competing hydrogen evolution reaction (HER), lowering the Faradaic efficiency of the process. Therefore, understanding the flooding behavior of GDEs is of major interest for further development of the process.Mathematic models can be applied here to describe the flooding state under the influence of electrowetting and elucidate its influence on the gas transport through the GDE. The validation of such models requires direct experimental measurements of the electrolyte saturation during eCO2R, which can be accomplished with the use of synchrotron radiation [2].In this work, experimental results for the direct measurement of the electrolyte saturation during eCO2R in sprayed silver GDEs are presented. In a first, these measurements were obtained in operando synchrotron tomography experiments, utilizing a high beam energy to penetrate through the 3 mm diameter GDE in the in-plane direction. The results indicate a higher beam absorption towards the gas side of the GDE, as well as higher absorption at increased current density. Key to the interpretation of these results is the disentanglement of the effects of concentration increase due to migration in the electric field and the actual increase in electrolyte saturation. The experimental results are used to validate a continuum model for a sprayed silver GDE in eCO2R which includes the effect of electrowetting on flooding behavior by introducing capillary pressure – saturation and contact angle – potential correlations [3]. A good agreement between model and tomography results is reached, showing an interplay between concentration increase and flooding effects.[1] Bienen, F., Paulisch, M. C., Mager, T., Osiewacz, J., Nazari, M., Osenberg, M., Ellendorff, B., Turek, T., Nieken, U., Manke, I., & Friedrich, K. A., Investigating the electrowetting of silver‐based gas‐diffusion electrodes during oxygen reduction reaction with electrochemical and optical methods. Electrochemical Science Advances (2022) e2100158.[2] Hoffmann, H., Paulisch, M. C., Gebhard, M., Osiewacz, J., Kutter, M., Hilger, A., Arlt, T., Kardjilov, N., Ellendorff, B., Beckmann, F., Markötter, H., Luik, M., Turek, T., Manke, I., & Roth, C., Development of a Modular Operando Cell for X-ray Imaging of Strongly Absorbing Silver-Based Gas Diffusion Electrodes. Journal of The Electrochemical Society 169 (2022) 044508.[3] Osiewacz, J., Löffelholz, M., Turek, T., Modeling the Influence of Electrolyte Distribution in Silver Gas Diffusion Electrodes for CO2 Electroreduction. ECS Meeting s 01 (2023) 1727. Figure 1

Novel high-throughput oxygen saturation measurements for quantifying the physiological performance of macroalgal early life stages.

Understanding how macroalgal forests will respond to environmental change is critical for predicting future impacts on coastal ecosystems. Although measures of adult macroalgae physiological responses to environmental stress are advancing, measures of early life-stage physiology are rare, in part due to the methodological difficulties associated with their small size. Here we tested a novel, high-throughput method (rate of oxygen consumption and production; ) via a sensor dish reader microplate system to rapidly measure physiological rates of the early life stages of three habitat-forming macroalgae, the kelp Ecklonia radiata and the fucoids Hormosira banksii and Phyllospora comosa. We measured the rate of O2 consumption (respiration) and O2 production (net primary production) to then calculate gross primary production (GPP) under temperatures representing their natural thermal range. The microplate system was suitable for rapidly measuring physiological rates over a temperature gradient to establish thermal performance curves for all species. The microplate system proved efficient for measures of early life stages of macroalgae ranging in size from approximately 50 μm up to 150 mm. This method has the potential for measuring responses of early life stages across a range of environmental factors, species, populations, and developmental stages, vastly increasing the speed, precision, and efficacy of macroalgal physiological measures under future ocean change scenarios.

Effect of pericapsular nerve group block on perioperative analgesia characteristics for hip fracture operations

Aims: Pericapsular nerve group (PENG) block is a new regional analgesia technique that has recently been used for perioperative analgesia for hip fracture operations. The purpose of this research was to examine the perioperative analgesic characteristics of PENG block in patients who were going to undergo spinal anesthesia for a hip fracture procedure. Methods: The study was conducted as a prospective randomized controlled study between February 2021 and May 2021 after ethics committee approval. Patients with consent were included in the study. The patients were randomly divided into two groups (Group-I and Group-II). Patients in Group I underwent a PENG block with a 0.25% concentration of 20 cc bupivacaine in the preoperative waiting room 30 minutes before the operation. Afterward, spinal anesthesia was applied in the operating room. The patients in Group II received only spinal anesthesia. Preoperative visual analog scale (VAS) scores were recorded for both groups in the preoperative period. ECG, arterial blood pressure, pulse, and oxygen saturation measurements were performed in all patients preoperatively, intraoperatively, and postoperatively. Pulse, arterial blood pressure, oxygen saturation measurements, and VAS scores were recorded in the lateral decubitus position before and at the 5th minute after spinal anesthesia. In addition, the comfort of the anesthetist who will administer the spinal anesthesia during the application was questioned (0: poor, 1: moderate, 2: good, 3: very good). All patients 5 min after spinal anesthesia It remained in the lateral position for the duration. VAS scores were recorded during the postoperative phase at the 0th, 2nd, 8th, 16th, and 24th hours, along with the time of the first analgesic administration. The total amount of tramadol and paracetamol taken during the first 24 hours following surgery was noted. Results: Patients; gender, age, body weight, height, BMI, and ASA values were statistically similar (p &gt; 0.05). In comparisons between the groups; During position, postoperative 2nd, 8th, 16th, 24th hours, and their sum, VAS values were found to be statistically lower in Group-I (p &lt; 0.05). While it was found that the first analgesic administration time was statistically longer in Group-I patients (p &lt; 0.001), the amounts of paracetamol and tramadol consumed in the first 24 hours were found to be statistically lower (p &lt; 0.001). In addition, the comfort of the anesthetist during spinal anesthesia was found to be better in Group-I (p: 0.014). Conclusion: PENG block can be used effectively as a part of perioperative multimodal analgesia in hip fracture surgery. PENG can reduce the pain levels of patients with hip fractures as well as reduce the need for additional analgesia. It also increases the comfort of the anesthetist who will administer regional anesthesia.