Effect of Local Cold Therapy on Arterial Blood Oxygen Saturation and Temperature Changes in Patients Undergoing Surgery

Background: Postoperative complications can endanger the patient's life and disrupt the recovery process if not properly managed. Local cold therapy can be a safe non-pharmacologic method to manage these side effects; however, it has not been highly considered. Objectives: This study was done to determine the effect of local cold therapy on arterial blood oxygen saturation and temperature changes in patients undergoing surgery. Methods: This quasi-experimental study was performed at Shahrekord University of Medical Sciences in 2019 on 60 patients undergoing thoracic and abdominal surgery selected by convenience sampling, and they were randomly assigned to the intervention and control groups. The intervention (local cold therapy) was performed for 48 hours after full consciousness, three times a day for 20 minutes to the intervention group. Data were collected before and after the intervention using a demographic questionnaire, pulse oximetry device, and thermometer. The data were analyzed based on the independent samples t-test, paired-samples t-test, and chi-square and Fishers’ exact tests by SPSS version 20 software. Results: The mean arterial blood oxygen saturation percentage (O2Sat%) during the intervention significantly increased in both groups (P < 0.05), but the rate of increase was significantly higher in the local cold group (P < 0.05). The results of within-group research showed that the mean temperature had significant differences in the local cold therapy group (P < 0.05), but the mean body temperature did not show a significant difference between the two groups (P < 0.05). Conclusions: Local cold therapy can be effectively trained and used by nurses to improve the O2Sat%. It did not affect postoperative body temperature. Further studies must be conducted to investigate the effects of local cold therapy on postoperative body temperature changes.

Correlation between Arterial Blood Oxygen Saturation, Underlying Diseases and Clinical Signs of COVID-19 Patients with Their Final Outcome

Introduction: COVID-19 can rapidly cause lung damage and severe respiratory distress and subsequently reduce oxygen saturation (SPO2), especially in generally ill patients, which may be exacerbated if severe clinical symptoms or underlying diseases are added. This may lead to deterioration of blood oxygenation or even increase the risk of death when severe clinical symptoms or underlying diseases are present. Therefore, the aim of this study was to Evaluation of the relationship between arterial blood oxygen saturation level and outcome in COVID-19 patients.Material and Methods: A cross-sectional study of 250 patients referred to Imam Sari Hospital with symptoms of respiratory infection, gastrointestinal, and general symptoms in January 2020 to September 2020. Data were analyzed using SPSS version 26.Results: 27 out of 250 patients died. There is a positive correlation between systemic patient, SPO2 and less than 90% with death results (P<0/02). Patients with heart disease (44.4%), cancer (30.1%), diabetes (11.1%), cerebrovascular accident (18.5%) died (P<0/05). There was no positive correlation between weakness, fever, dyspnea, nausea, and diarrhea and appetite loss with death.Conclusion: Based on the present study, it was found that patients whose clinical symptoms were associated with underlying disease and SPO2 to a severe and critical degree had a higher risk of adverse outcome such as death. People with underlying conditions such as DM, CVD, HTN, and a history of angiography and cancer are also more likely to die due to COVID-19. Most deaths in the present study had low SPO2 at before admission, indicating a strong association between patient mortality and severity of lung involvement and low SPO2.

Short-term facilitation of breathing upon cessation of hypoxic challenge is impaired in male but not female endothelial NOS knock-out mice

Decreases in arterial blood oxygen stimulate increases in minute ventilation via activation of peripheral and central respiratory structures. This study evaluates the role of endothelial nitric oxide synthase (eNOS) in the expression of the ventilatory responses during and following a hypoxic gas challenge (HXC, 10% O2, 90% N2) in freely moving male and female wild-type (WT) C57BL6 and eNOS knock-out (eNOS–/–) mice. Exposure to HXC caused an array of responses (of similar magnitude and duration) in both male and female WT mice such as, rapid increases in frequency of breathing, tidal volume, minute ventilation and peak inspiratory and expiratory flows, that were subject to pronounced roll-off. The responses to HXC in male eNOS–/– mice were similar to male WT mice. In contrast, several of the ventilatory responses in female eNOS–/– mice (e.g., frequency of breathing, and expiratory drive) were greater compared to female WT mice. Upon return to room-air, male and female WT mice showed similar excitatory ventilatory responses (i.e., short-term potentiation phase). These responses were markedly reduced in male eNOS–/– mice, whereas female eNOS–/– mice displayed robust post-HXC responses that were similar to those in female WT mice. Our data demonstrates that eNOS plays important roles in (1) ventilatory responses to HXC in female compared to male C57BL6 mice; and (2) expression of post-HXC responses in male, but not female C57BL6 mice. These data support existing evidence that sex, and the functional roles of specific proteins (e.g., eNOS) have profound influences on ventilatory processes, including the responses to HXC.

A Model for the Digital Method of Measuring LED Incident Photocurrent

Pulse oximeters and other light based sensor types are used to monitor arterial blood oxygen levels, heart rate, and much more that rely on LEDs and photodiodes. The conventional method of using photodiodes to detect light signals is accurate, but requires relatively expensive hardware processing to extract the signal. Digital sensing of light using an LED provides a low-cost alternative by using a voltage threshold timing method. However, the accuracy of this method is dependant on the microcontroller clock speed and suffers from variable sample rate (100 us to 10 ms). This paper develops a model for a digital light sensing method using only a microcontroller’s ADC and timer, and an LED. Using the voltage discharge curve of a reverse biased LED, the sensor is capable of accurately detecting light intensities ranging from 0–3885 mcd at a sample period of 500 us. A linear relationship was found through the incident light intensity ranges of 0 to 3880 mcd. The model fit the expected experimental values, with an estimated photocurrent ranging from 10 pA to 55 nA. With an R2 of 0.9997, the model demonstrates the digital sensing method linearly responds to incident light intensity and can simplify the design of pulse oximeters and similar light based sensor types.

Effects of water stably-enriched with oxygen as a novel method of tissue oxygenation on mitochondrial function, and as adjuvant therapy for type 2 diabetes in a randomized placebo-controlled trial

Background Diabetes mellitus is associated with inadequate delivery of oxygen to tissues. Cellular hypoxia is associated with mitochondrial dysfunction which increases oxidative stress and hyperglycaemia. Hyperbaric oxygenation therapy, which was shown to improve insulin sensitivity, is impractical for regular use. We evaluated the effects of water which is stably-enriched with oxygen (ELO water) to increase arterial blood oxygen levels, on mitochondrial function in the presence of normal- or high-glucose environments, and as glucose-lowering therapy in humans. Methods We compared arterial blood oxygen levels in Sprague-Dawley rats after 7 days of ad libitum ELO or tap water consumption. Mitochondrial stress testing, and flow cytometry analysis of mitochondrial mass and membrane potential, were performed on human HepG2 cells cultured in four Dulbecco’s Modified Eagle Medium media, made with ELO water or regular (control) water, at normal (5.5 mM) or high (25 mM) glucose concentrations. We also randomized 150 adults with type 2 diabetes (mean age 53 years, glycated haemoglobin HbA1c 8.9% [74 mmol/mol], average duration of diabetes 12 years) to drink 1.5 litres daily of bottled ELO water or drinking water. Results ELO water raised arterial oxygen tension pO2 significantly (335 ± 26 vs. 188 ± 18 mmHg, p = 0.006) compared with tap water. In cells cultured in control water, mitochondrial mass and membrane potential were both significantly lower at 25 mM glucose compared with 5.5 mM glucose; in contrast, mitochondrial mass and membrane potential did not differ significantly at normal or high glucose concentrations in cells cultured in ELO water. The high-glucose environment induced a greater mitochondrial proton leak in cells cultured in ELO water compared to cells cultured in control medium at similar glucose concentration. In type 2 diabetic adults, HbA1c decreased significantly (p = 0.002) by 0.3 ± 0.7% (4 ± 8 mmol/mol), with ELO water after 12 weeks of treatment but was unchanged with placebo. Conclusions ELO water raises arterial blood oxygen levels, appears to have a protective effect on hyperglycaemia-induced reduction in mitochondrial mass and mitochondrial dysfunction, and may be effective adjuvant therapy for type 2 diabetes.

Impaired carotid body hypoxic sensing in mice deficient in olfactory receptor 78

ABSTRACTCarotid bodies are the sensory organs for detecting hypoxemia (decreased arterial blood oxygen levels) and ensuing chemo reflex is a major regulator of breathing and blood pressure. Chang et al (2015) proposed that olfactory receptor 78 (Olfr78) plays a major role in hypoxic sensing by the carotid body. However, such a possibility was questioned by a subsequent study ((Torres-Torrelo et al. 2018). The discrepancy between the two reports prompted the present study to re-examine the role of Olfr78 in hypoxic sensing by the carotid body (CB). Studies were performed on age and gender matched Olfr78 knock out mice generated on BL6 and JAX backgrounds and corresponding wild type mice. Breathing was monitored by plethysmography in un-sedated and efferent phrenic nerve activity in anesthetized mice. Carotid body sensory nerve activity was determined ex vivo and [Ca2+]i responses were monitored in isolated glomus cells, the primary O2 sensing cells of the carotid body. Olfr78 null mice on both BL6 and JAX backgrounds exhibited attenuated hypoxic ventilatory response, whereas breathing responses to CO2 were unaffected. The magnitude of hyperoxia-induced depression of breathing (Dejour’s test), which is an indirect measure of carotid body hypoxic sensing, was markedly reduced in Olfr78 mutant mice on both background strains. Furthermore, carotid body sensory nerve and glomus cell [Ca2+]i responses to hypoxia were attenuated in BL6 and JAX Olfr78 null mice. These results suggest that Olfr78 plays an important role in hypoxic sensing by the carotid body.

Infrared monitoring of the dynamics of the local temperature as a symptom of adaptation to hypoxia and efficiency of antihypoxic drugs

The literature review shows that the general body temperature and the local temperature of individual organs of humans and animals have a significant impact on their reaction to the lack of arterial blood, oxygen and anti-hypoxic and anti-ischemic agents. It is shown that human and animal body organs have different resistance to hypoxia. The least resistant to ischemia and hypoxia is the brain, and it is the first hypoxia damaged cerebral cortex. It is shown that with a lack of oxygen, the death of neurons in the brain can be effectively prevented by timely administration of oxygen to the brain and/or lowering its local temperature. However, to date, no technologies have been developed that provide an immediate increase in the concentration of oxygen and/or a decrease in the local temperature in the brain of people while maintaining their performance. Under these conditions, professor V.M. Vinogradov proposed to find the possibility of extending the life of brain cells in conditions of lack of oxygen using drugs that have been called antihypoxants. Technologies of infrared diagnostics of hypoxia, estimation of reserves of adaptation to it and ways of estimation of efficiency of antihypoxants are described.