Automobile Pollution and Risk of Impaired Lung Function and Oxygen Saturation among Vendors Near Road Traffic in Brazzaville, Congo

Context: Automobile pollution is becoming a potential threat to the cardiorespiratory health of the urban population of sub-Saharan Africa. The present study aims to evaluate the level of concentrations of fine particles (PM2.5 and PM10) near road traffic and the effects of exposure to automobile pollutants on pulmonary function and arteriolar blood oxygen saturation among sellers around road traffic. Materials and Methods: The study recruited 48 healthy people carrying out a sales activity near road traffic. PM2.5 and PM10 measurements were taken from 6 a.m. to 6 p.m. using a Temtop Airing-1000 portable particle detector. Spirometric measurements were taken in the morning and in the evening from a portable Spirobank G spirometer. Oxygen saturation measurements were also taken in the morning and evening using a Pulse oxymeter CMS50D pulse oxymeter. Results: Mean values of forced vital capacity (FVC), forced expiratory volume in one second (FEV1), peak expiratory flow (PEF), and forced expiratory flow between 25% and 75% of forced vital capacity (FEF25 - 75) recorded in the evening were significantly lower than those obtained in the morning in the subjects of the total group and in the men. Only the mean values of PEF and FEF25 - 75 obtained in the evening were significantly lower than those recorded in the morning in women. Minimum PM2.5 values recorded near road traffic were negatively correlated with evening PEF in men, while maximum PM10 values were negatively correlated with evening PEF in women. The blood oxygen saturation recorded in the evening was significantly lower than that obtained in the morning. Conclusion: Short-term exposure to automobile pollutants has adverse effects on lung function and oxygen saturation in people carrying out a sales activity near road traffic.

Neuroprotection of hyperbaric oxygen therapy in sub-acute traumatic brain injury:not by immediately improving cerebral oxygen saturation and oxygen partial pressure

Although hyperbaric oxygen （HBO） therapy can promote the recovery of neural function in patients who have suffered traumatic brain injury （TBI）, the underlying mechanism is unclear. We hypothesized that hyperbaric oxygen treatment plays a neuroprotective role in TBI by increasing regional transcranial oxygen saturation （rSO2） and oxygen partial pressure （PaO2）. To test this idea, we compared two groups： a control group with 20 healthy people and a treatment group with 40 TBI patients. The 40 patients were given 100% oxygen of HBO for 90 minutes. Changes in rSO2 were measured. The controls were also examined for rSO2 and PaO2, but received no treatment, rSO2 levels in the patients did not differ significantly after treatment, but levels before and after treatment were significantly lower than those in the control group. PaO2 levels were significantly decreased after the 30-minute HBO treatment. Our findings suggest that there is a disorder of oxygen metabolism in patients with sub-acute TBI. HBO does not immediately affect cerebral oxygen metabolism, and the underlying mechanism still needs to be studied in depth.

Retinal vessel oxygen saturation in healthy subjects and early branch retinal vein occlusion

AIM： To measure the retinal oxygen saturation in healthy subjects and early branch retinal vein occlusion（BRVO） in Chinese population.METHODS： The retinal vessel oxygen saturation of the healthy subjects and BRVO patients were measured by a noninvasive retinal oximeter（Oxymap ehf.,Reykjavik,Iceland）.RESULTS： The study included 22 patients with unilateral BRVO（mean age： 55.1±8.8y） in the study group and 91 healthy participants（mean age： 37.5±14.0y） in the control group.In the healthy individuals,mean arterial and venous oxygen saturation were significantly（P〈0.001）higher in the superior nasal quadrant（98.5%±10.1%and 57.3%±8.7%,respectively） than in the inferior nasal quadrant（94.2%±9.0% and 54.1%±9.6%,respectively）,followed by the superior temporal quadrant（89.1%±10.1%and 51.9%±8.9%,respectively） and the inferior temporal quadrant（86.4%±9.4% and 46.6%±9.6%,respectively）.In patients with ischemic BRVO,arterial oxymetric values were significantly higher and venous measurements significantly lower for the affected vessel（107.5%±9.7% and46.4%±14.2%,respectively） than the unaffected vessel in the same eye（99.2%±12.2% and 55.5%±7.9%,respectively）and as compared to the vessel in the unaffected fellow eye（93.1%±6.9% and 55.7%±6.8%）（P=0.005 and P=0.02,respectively）.In the patients with non-ischemic BRVO,mean venous oxygen saturation was lower in the affected vein（39.8%±12.2%） than in the unaffected vessels of the same eye（50.8%±10.5%） and in the fellow eye（58.21%±5.7%）（P=0.03）.Mean arterial oxygen saturation did not differ significantly（P=0.42） between all three groups.CONCLUSION： In patients with BRVO,the venous oxygen saturation in the affected vessels is decreased potentially due to decreased blood velocity and flow.Interestingly,thearterial oxygen saturation in eyes with ischemic BRVO is increased in the affected arteries.

Effects of Integrative Chinese and Western Medicine on Arterial Oxygen Saturation in Patients with Severe Acute Respiratory Syndrome

Objective: To evaluate the effects of treatment of integrative Chinese and Western medicine (ICWM) on arterial oxygen saturation (SaO2) in patients with severe acute respiratory syndrome (SARS). Methods:The non-randomized, controlled trial was conducted on 447 SARS patients treated synchronously with western conventional treatment (WM group, n = 171) alone and ICWM (ICWM group, n = 276). The changes of the cases with normal level (≥95% ) or abnormal level (<95% ) SaO2 were observed dynamically. Results: In the 3rd-14th day of the therapeutic course, the percentage of patients with normal SaO2 in the ICWM group was higher than that in the WM group (OR = 0.5178, P = 0.0038), and this tendency was more evident in patients of the severe type (OR = 0. 18, P = 0. 0001). However, the statistical significance of difference was only shown in patients for whom the ICWM treatment started in the early period after the onset (≤7 days after it, OR = 0.3803, P = 0.006), but not shown in those who received ICWM treatment later in the mid-late period of SARS ( P>0. 05). Conclusion: ICWM treatment, particularly when it is used for intervention in the early stage, is beneficial for maintaining normal SaO2 in SARS patients.

Effect of Hemodilution on Fluctuation of Cerebral Oxygen Saturation during Cardiopulmonary Bypass in Children with Cyanotic Congenital Heart Disease

Background:In patients with cyanotic congenital heart disease(CHD),cerebral oxygenation may be maintained by elevations in hematocrit(Hct).Hemodilution accompanying cardiopulmonary bypass(CPB),however,can disrupt cerebral oxygen balance,leading to fluctuations in cerebral oxygen saturation(ScO_(2)).The present study investigated the effects of Hct changes on the fluctuation of ScO_(2)during CPB in cyanotic CHD using performance measurement(PM).Methods:Children with CHD(51 acyanotic and 46 cyanotic)who had undergone cardiac surgery using CPB were enrolled.Median performance error(MDPE),median absolute performance error(MDAPE),and wobble parameters of ScO_(2)were calculated before(reference value),during,and after CPB.Correlations of PM parameters with Hct and reductions in Hct(ΔHct)were also evaluated.Results:Before CPB,patients with cyanotic CHD had lower MDPE and larger wobble than those with acyanotic CHD,although mean ScO_(2)did not differ significantly between the two groups.During CPB,ScO_(2)of acyanotic CHD increased asΔHct increased,but PM variables were not associated withΔHct.In cyanotic CHD,MDPE(r=−0.324,p=0.032)and MDAPE(r=0.339,p=0.024)correlated significantly withΔHct during CPB.After CPB,MDPE(r=0.574,p=0.025)and MDAPE(r=−0.543,p=0.036)were significantly correlated with Hct in children with cyanotic CHD who underwent palliative surgery.Conclusion:Therefore,ScO_(2)fluctuation during CPB in children with cyanotic CHD may be affected by the decrease in Hct,suggesting that excessive hemodilution can negatively influence the maintenance of cerebral oxygenation in these patients.

Changes and significance of retinal blood oxygen saturation and oxidative stress indexes in patients with diabetic retinopathy

BACKGROUND Diabetic retinopathy(DR)is a diabetic complication that can severely affect the patients’vision,eventually leading to blindness.DR is the most important manifestation of diabetic micro-vasculopathy and is mainly related to the course of diabetes and the degree of blood glucose control,while the age of diabetes onset,sex,and type of diabetes have little influence on it.AIM To explore the changes in blood oxygen saturation and oxidative stress indices of retinal vessels in patients with DR.METHODS In total,94 patients(94 eyes)with DR(DR group)diagnosed at Jianyang people’s Hospital between March 2019 and June 2020,and 100 volunteers(100 eyes)(control group)without eye diseases,were included in this study.Arterial and venous blood oxygen saturation,retinal arteriovenous vessel diameter,and serum oxidative stress indicators in the two groups were compared.Based on the stage of the disease,the DR group was divided into the simple DR and proliferative DR groups for stratified analysis.RESULTS The oxygen saturation of the retinal vessels in the DR group was significantly higher than that in the control group(P<0.05).The retinal vessel diameters between the DR and control groups were not significantly different.The serum malondialdehyde(MDA)and 8-hydroxydehydroguanosine(8-OHdG)levels in the DR group were significantly higher than those in the control group(P<0.05).The serum superoxide dismutase(SOD)and reduced glutathione(GSH)levels in the DR group were significantly lower than those in the control group (P < 0.05). The oxygensaturation of the retinal vessels in the patients with proliferative DR was significantly higher thanthat in the patients with simple DR (P < 0.05). The retinal vessel diameter in patients with proliferativeDR was not significantly different from that of patients with simple DR (P > 0.05). SerumMDA and 8-OHdG levels in patients with proliferative DR were significantly higher than those inpatients with simple DR (P < 0.05). Serum SOD and GSH levels in patients with proliferative DRwere significantly lower than those in patients with simple DR (P < 0.05).CONCLUSIONIncreased blood oxygen saturation of retinal arteries and veins and increased oxidative stressdamage in patients with DR may be associated with decreased retinal capillary permeability andarterial oxygen dispersion, possibly reflecting the patient’s condition.

Clinical application of vascular occlusion test based on tissue oxygen saturation monitoring

The vascular occlusion test (VOT) is an experiment that simulates the process of distal ischemia-reperfusion of tissue based on the monitoring of tissue oxygen saturation (StO2) to obtain VOT parameters related to StO2 changes to evaluate microcirculation function of the measured muscle tissue. VOT has the advantages of real-time, noninvasive and continuous, and is widely used to evaluate the functional status of peripheral microcirculation and the relationship between microcirculation changes and prognosis of patients. In clinical work, doctors mainly focus on hemodynamics of patients, while microcirculation function is often neglected due to the lack of real-time monitoring methods, which may lead to severe poor prognosis of patients, especially patients with critical illness. This paper focuses on the clinical application of vascular occlusion test based on tissue oxygen saturation monitoring.

Speed-resolved blood perfusion and oxygen saturation in human skin response to thermal stimulation

The functional status of vessels can be determined by assessing blood perfusion.By integrating diffuse reflectance spectroscopy(DRS)and Laser Doppler Flowmetry(LDF),the speed-resolved blood perfusion and blood oxygen saturation can be measured simultaneously by Enhanced Perfusion and Oxygen Saturation(EPOS).The dataset presented in this descriptor contains EPOS data recorded from a forearm point exposed to different levels of thermal stimulation,the classical LDF at control points,the R-R time series and data regarding the subjects’characteristics.All data were recorded from 60 recruited healthy subjects.Half of the subjects received different levels of thermal stimulation,and half of them were blank controls.We believe that this dataset will lead to the development of local blood perfusion methods that can be used to index vessel function assessments.This publicly available dataset will be beneficial to the microcirculation evaluation.

Trajectories of oxygen saturation within 6–72 hours after birth in neonates at moderate altitude:a prospective longitudinal cohort study

Trajectories of pulse oxygen saturation(SpO_(2))within the first few days after birth are important to inform the strategy for identifying asymptomatic hypoxemic disease but remain poorly substantiated at higher altitudes.Methods We performed a longitudinal cohort study with consecutive neonates at a local hospital in Luchun County,China,at an altitude of 1650 m between January and July 2020.We repeatedly measured the pre-and post-ductal SpO_(2)values at 6,12,18,24,36,48,and 72 hours after birth for neonates without oxygen supplements.All neonates underwent echocardiography and were followed up to 42 days after discharge.We included neonates without hypoxemic diseases to characterize the trajectories of SpO_(2)over time using a linear mixed model.We considered the 2.5th percentile as the reference value to define hypoxemic conditions.Results A total of 1061 neonates were enrolled.Twenty-five had non-cardiac hypoxemic diseases,with 84%(21/25)presenting with abnormal SpO_(2)within 24 hours.One had tetralogy of Fallot identified by echocardiography.Among the 1035 asymptomatic neonates,SpO_(2)values declined from 6 hours after birth,reached a nadir at 48 hours,and tended to level off thereafter,with identical patterns for both pre-and post-ductal SpO_(2).The reference percentile was 92%for both pre-and post-ductal SpO_(2)and was time independent.Conclusions A decline within 48 hours features SpO_(2)trajectories within the first 72 hours at moderate altitude.Our findings suggest that earlier screening may favorably achieve a benefit–risk balance in identifying asymptomatic hypoxemic diseases in this population.

High Arterial Oxygen Saturation in the Acclimatized Lowlanders Living at High Altitude

Blood oxygen saturation(SpO_(2))is a key indicator of oxygen availability in the body.It is known that a low SpO_(2)at high altitude is associated with morbidity and mortality risks due to physiological hypoxemia.Previously,it was proposed that the lowlander immigrants living at high altitude should have a lower SpO_(2)level compared to the highlander natives,but this proposal has not been rigorously tested due to the lack of data from the lowlander immigrants living at high altitude.In this study,we compared arterial oxygen saturation of 5929 Tibetan natives and 1034 Han Chinese immigrants living at altitudes ranging from 1120 m to 5020 m.Unexpectedly,the Han immigrants had a higher SpO_(2)than the Tibetan natives at the same high altitudes.At the same time,there is a higher prevalence of chronic mountain sickness in Han than in Tibetans at the same altitude.This result suggests that the relatively higher SpO_(2)level of the acclimatized Han is associated with a physiological cost,and the SpO_(2)level of Tibetans tends to be sub-optimal.Consequently,SpO_(2)alone is not a robust indicator of physiological performance at high altitude.

Investigation of one-lung ventilation postoperative cognitive dysfunction and regional cerebral oxygen saturation relations

Objective： To explore the relationship of postoperative cognitive dysfunction （POCD） in one-lung ventilation （OLV） patients and regional cerebral oxygen saturation （rSO2）. Methods： Twenty-nine male and twenty-one female cases of OLV received thoracic surgery, with American Standards Association （ASA） physical status being at Grades Ⅰ-Ⅲ. Neuropsychological tests were performed on the day before operation and 7 d after operation, and there was an intraoperative continuous monitoring of rSO2. The values of rSO2 before anesthesia induction （t1）, at the beginning of OLV （t2）, and at the time of OLV 30 min （t3）, OLV 60 min （t4）, the end of OLV （t5）, and the end of surgery （t6） were recorded. The intraoperative average of rSO2 （ rSO2 ）, the intraoperative minimum value of rSO2 （rSO2, rn=n）, and the reduced maximum percentage of rSO2 （rSO2, %max） when compared with the baseline value were calculated. The volume of blood loss, urine output, and the amount of fluid infusion was recorded. Results： A total of 14 patients （28%） in the 50 cases suffered from POCD. The values of mini-mental state examination （MMSE）, the digit span and the digit symbol on the 7th day after the operation for POCD in OLV patients were found to be significantly lower than those before the operation （P〈0.05）. The values of MMSE and vocabulary fluency scores were significantly lower than those in the non-POCD group （P〈0.05）. The values of rSO2 in the POCD group of OLV patients at t2 and t3 and the values of rSO2 in the non-POCD group at t2 were found to be significantly higher than those at tl （P〈0.05）. The values of rSO2, %max in the POCD group were significantly higher than those in the non-POCD group （P〈0.05）. When the value of rSO2, %max is more than 10.1%, it may act as an early warning index for cognitive function changes, Conclusions： POCD after OLV may be associated with a decline in rSO2.

Relationship between post-operative cognitive dysfunction and regional cerebral oxygen saturation and β-amyloid protein

Objective： To investigate the relationship between post-operative cognitive dysfunction（POCD） and regional cerebral oxygen saturation（rSO2） and β-amyloid protein（Aβ） in patients undergoing laparoscopic pancreaticoduodenectomy. Methods： Fifty patients undergoing elective laparoscopic pancreaticoduodenectomy received five groups of neuropsychological tests 1 d pre-operatively and 7 d post-operatively, with continuous monitoring of rSO2 intra-operatively. Before anesthesia induction（t0）, at the beginning of laparoscopy（t1）, and at the time of pneumoperitoneum 120 min（t2）, pneumoperitoneum 240 min（t3）, pneumoperitoneum 480 min（t4）, the end of pneumoperitoneum（t5）, and 24 h after surgery, jugular venous blood was drawn respectively for the measurement of Aβ by enzyme-linked immunosorbent assay（ELISA）. Results： Twenty-one cases of the fifty patients suffered from POCD after operation. We found that the maximum percentage drop in rSO2（rSO2, %max） was significantly higher in the POCD group than in the non-POCD group. The rSO2, %max value of over 10.2% might be a potential predictor of neurocognitive injury for those patients. In the POCD group, the plasma Aβ levels after 24 h were significantly higher than those of pre-operative values（P〈0.01）. After 24 h, levels of plasma Aβ in the POCD group were significantly higher than those in the non-POCD group（P〈0.01）. Conclusions： The development of POCD in patients undergoing laparoscopic pancreaticoduodenectomy is associated with alterations of rSO2 and Aβ. Monitoring of rSO2 might be useful in the prediction of POCD, and Aβ might be used as a sensitive biochemical marker to predict the occurrence of POCD.

Highly sensitive,sub-microsecond polymer photodetectors for blood oxygen saturation testing

Bottom surface of active layers and interface of indium tin oxide(ITO)electrodes and active layers play a crucial role in determining the performance of polymer photodetectors with photomultiplication(PM-PPDs).The interfacial trapped electron distribution closing to ITO electrodes will determine spectral response range and external quantum efficiency(EQE)of PMPPDs.The bottom interface is more sensitive than top interface when light is coming from the ITO side,and the larger density of generated charge on the bottom interfaces will induce interfacial band more bending for efficient charge tunneling injection.Highly sensitive and sub-microsecond PM-PPDs are achieved with PMBBDT:Y6(100:7,w/w)as active layers under forward bias,yielding EQE of 18,700%at 320 nm,21,700%at 600 nm and 16,400%at 810 nm under a bias of 7 V,respectively,as well as fast response time of 79μs.The high EQE of the PM-PPDs is attributed to efficient hole tunneling injection from ITO electrode under forward bias.The electron traps closing to ITO electrode will be quickly filled up when light is coming from ITO side,leading to interfacial band more bending for hole tunneling injection.Importantly,the PM-PPDs is performed to measure heart rate(HR)and blood oxygen saturation(SpO_(2)),and the measured data by the PM-PPDs are very similar with those obtained by commercial photodetectors.

Application value of dexmedetomidine in anesthesia for elderly patients undergoing radical colon cancer surgery

BACKGROUND Colon cancer presents a substantial risk to the well-being of elderly people worldwide.With advancements in medical technology,surgical treatment has become the primary approach for managing colon cancer patients.However,due to age-related physiological changes,especially a decline in cognitive function,older patients are more susceptible to the effects of surgery and anesthesia,increasing the relative risk of postoperative cognitive dysfunction(POCD).There-fore,in the surgical treatment of elderly patients with colon cancer,it is of pa-ramount importance to select an appropriate anesthetic approach to reduce the occurrence of POCD,protect brain function,and improve surgical success rates.METHODS One hundred and seventeen patients with colon cancer who underwent elective surgery under general anesthesia were selected and divided into two groups:A and B.Group A received Dex before anesthesia induction,and B group received an equivalent amount of normal saline.Changes in the mini-mental state exami-nation,regional cerebral oxygen saturation(rSO2),bispectral index,glucose uptake rate(GluER),lactate production rate(LacPR),serum S100βand neuron-specific enolase(NSE),POCD,and adverse anesthesia reactions were compared between the two groups.RESULTS Surgical duration,duration of anesthesia,and intraoperative blood loss were comparable between the two groups(P>0.05).The overall dosage of anesthetic drugs used in group A,including propofol and remifentanil,was significantly lower than that used in group B(P<0.05).Group A exhibited higher rSO2 values at the time of endotracheal intubation,30 min after the start of surgery,and immediately after extubation,higher GluER values and lower LacPR values at the time of endotra-cheal intubation,30 min after the start of surgery,immediately after extubation,and 5 min after extubation(P<0.05).Group A exhibited lower levels of serum S100βand NSE 24 h postoperatively and a lower incidence of cognitive dysfunction on the 1st and 5th postoperative days(P<0.05).CONCLUSION The use of Dex in elderly patients undergoing radical colon cancer surgery helps maintain rSO2 Levels and reduce cerebral metabolic levels and the incidence of anesthesia-and surgery-induced cognitive dysfunction.

Pulse oximetry in pediatric care:Balancing advantages and limitations

BACKGROUND Pulse oximetry has become a cornerstone technology in healthcare,providing non-invasive monitoring of oxygen saturation levels and pulse rate.Despite its widespread use,the technology has inherent limitations and challenges that must be addressed to ensure accurate and reliable patient care.AIM To comprehensively evaluate the advantages,limitations,and challenges of pulse oximetry in clinical practice,as well as to propose recommendations for optimizing its use.METHODS A systematic literature review was conducted to identify studies related to pulse oximetry and its applications in various clinical settings.Relevant articles were selected based on predefined inclusion and exclusion criteria,and data were synthesized to provide a comprehensive overview of the topic.RESULTS Pulse oximetry offers numerous advantages,including non-invasiveness,real-time feedback,portability,and costeffectiveness.However,several limitations and challenges were identified,including motion artifacts,poor peripheral perfusion,ambient light interference,and patient-specific factors such as skin pigmentation and hemoglobin variants.Recommendations for optimizing pulse oximetry use include technological advancements,education and training initiatives,quality assurance protocols,and interdisciplinary collaboration.CONCLUSION Pulse oximetry is crucial in modern healthcare,offering invaluable insights into patients’oxygenation status.Despite its limitations,pulse oximetry remains an indispensable tool for monitoring patients in diverse clinical settings.By implementing the recommendations outlined in this review,healthcare providers can enhance the effectiveness,accessibility,and safety of pulse oximetry monitoring,ultimately improving patient outcomes and quality of care.

Effects of oxygen concentration and flow rate on cognitive ability and physiological responses in the elderly

The supply of highly concentrated oxygen positively affects cognitive processing in normal young adults. However, there have been few reports on changes in cognitive ability in elderly subjects following highly concentrated oxygen administration. This study investigated changes in cognitive ability, blood oxygen saturation （%）, and heart rate （beats/min） in normal elderly subjects at three different levels of oxygen [21% （1 L/min）, 93% （1 L/min）, and 93% （5 L/min）] administered during a 1-back task. Eight elderly male （75.3 ＋ 4.3 years old） and 10 female （71.1 ＋ 3.9 years old） subjects, who were normal in cognitive ability as shown by a score of more than 24 points in the Mini-Mental State Examination-Korea, participated in the experiment. The experiment consisted of an adaptation phase after the start of oxygen administration （3 minutes）, a control phase to obtain stable baseline measurements of heart rate and blood oxygen saturation before the task （2 minutes） and a task phase during which the 1-back task was performed （2 minutes）. Three levels of oxygen were administered throughout the three phases （7 minutes）. Blood oxygen saturation and heart rate were measured during each phase. Our results show that blood oxygen saturation increased, heart rate decreased, and response time in the 1-back task decreased as the concentration and amount of administered oxygen increased. This shows that administration of sufficient oxygen for optimal cognitive functioning increases blood oxygen saturation and decreases heart rate.

Multispectral imaging of acute wound tissue oxygenation

This paper investigates the appropriate range of values for the transcutaneous blood oxygen saturation(StO2)of granulating tissues and the surrounding tissue that can ensure timely wound recovery.This work has used a multispectral imaging system to collect wound images at wave-lengths ranging between 520 nm and 600 nm with a resolution of 10 nm.As part of this research,a pilot study was conducted on three injured individuals with superfcial wounds of different wound ages at different skin locations.The S_(t)O_(2)value predicted for the examined wounds using the Extended Modified Lambert-Beer model revealed a mean S_(t)O_(2)of 61±10.3%compared to 41.6±6.2%at the surrounding tissues,and 50.1±1.53%for control sites.These preliminary results contribute to the existing knowledge on the possible range and variation of wound bed S_(t)O_(2)that are to be used as indicators of the functioning of the vasomotion system and wound health.This study has concluded that a high S_(t)O_(2)of approximately 60%and a large fuctuation in this value should precede a good progression in wound healing.

Effects of various anesthetic techniques and PaCO_2 levels on cerebral oxygen balance in neurosurgical patients

Objective: To assess the effects of various anesthetic techniques and PaCO2 levels on cerebral oxygen supply/consumption balance during craniotomy for removal of tumors, and to explore an anesthetic technique for neurosur-gery and an appropriate degree of PaCO2 during neuroanesthesia. Methods: One hundred and fourteen patients with supratentorial tumors for elective craniotomy, ASA grade I - II , were randomly allocated to six groups. Patients were anesthetized with continuous intravenous infusion of 2% procaine 1. 0 mg · kg-1 · min-1 in Group I , inhalation of 1. 0% - 1. 5% isoflurane in Group II , and infusion of 2% procaine 0. 5 mg·kg · min-1 combined with inhalation of 0.5% -0.7% isoflurane in Group III during the period of study. The end-tidal pressure of CO2(PET CO2 ) was maintained at 4.0 kPa in these 3 groups. In Group IV, V and VI, the anesthetic technique was the same as that in Group I but the PETCO2 was adjusted to 3. 5, 4. 0 and 4. 5 kPa respectively for 60 min during which the study was performed. The radial arterial and retrograde jugular venous blood samples were obtained at the onset and the end of this study for determining jugular venous bulb oxygen saturation ( SjvO2 ) , arteriovenous oxygen content difference (AVDO2) and cerebral extraction of oxygen (CEO2). Results: In Group I and I SjvO2, AVDO2 and CEO2 remained stable. Although SjvO2 kept constant, AVDO2 and CEO2 decreased significantly (P <0. 05) in Group II. Moreover, AVDO2 and CEO2 in Group II were significantly lower than those of Group III (P<0. 05). In Group IV, 60 min after hyperventilation, SjvO2 and jugular venous oxygen content ( CjvO2 ) decreased markedly (P < 0. 01 ) while CEO2 increased significantly ( P <0.01) . In addition, SjvO2, CjvO2 and CEO2 in Group IV were significantly different from the corresponding parameters in Group V and Group VI (P <0. 05) . In view of sustained excessive hyperventilation, SjvO2 was less than 50% in 37.5% patients of Group IV. Conclusion: Anesthesia with intravenous infusion of procaine combined with isoflurane inhalation proved to be more suitable for neurosurgery than procaine intravenous anesthesia or isoflurane inhalation anesthesia alone. PaCO2 at 4.0 -4. 5 kPa in patients undergoing craniocerebral surgery during neuroanesthesia would be beneficial in both decreasing ICP and maintaining cerebral oxygen supply/consumption balance.

The Feasibility of Flat, Portable and Wireless Device for Non-Invasive Peripheral Oxygenation Measurement over the Entire Body

Peripheral oxygenation level (SpO2) can provide vital information on body functions. Continuous monitoring facilitates effective diagnosis and treatment and can even be lifesaving. Clinical device monitor SpO2 using a clip, and measure light transmission through the tissue. This method limits the body locations of the clip’s placement and is sensitive to body movement, which hampers continuous SpO2 monitoring during wakefulness or sleep, thus decreasing its usability in clinics and its accessibility in homecare usage. We developed a portable, wireless, flat and low cost prototype for continuous monitoring of SpO2 that overcomes those limitations. The prototype enables convenient measurement in larger variety of body locations by spectrophotometric measurements of changes in the optical reflectance unlike other device that measure absorption through the tissue. The original design and signal processing enable reliable signal acquisition, synchronization and control. An Android’s application was developed to provide a user friendly interface for results display on smartphones. The prototype’s measurements were compared to commercial device that simultaneously measured heart rate frequency, transcutaneous oxygen tension (tcPO2) and SpO2. The prototype’s measurements accurately reflected changes caused by blood pulses, were correlated to the heart rate, and were sensitive to changes in oxygen saturation. Excellent real time behavior and synchronization were demonstrated between the hardware and smartphone software. Our prototype thus enables convenient SpO2 measurement over the entire body, while maintaining accuracy comparable to commercial device. Its smartphone application enables accessible and understandable results display to patients, care-givers and healthcare professionals. The application’s display and alert calibration flexibility facilitates the prototype’s usage in changing medical requirements and for various disease and conditions. A device based on this prototype can monitor continuously and accurately patients’ SpO2 without limiting their everyday activities or disturbing their sleep and can thus significantly im-prove their medical care in both clinics and home.

Signals Analysis and Clinical Validation of Blood and Oxygen Data in Human Brain

With a self-made near-infrared analytical instrument to blood and oxygen parameters in human brain, 80 cases in which 20 are healthy persons and 30 are anaesthetised cases and others are patients with heart function lack is taken to examine, and the data of blood and oxygen in brain tissue were collected and analyzed by the method of power spectrum and correlation function. The results indicate that: (1) The average brain oxygen saturation of healthy persons and anaesthetised cases is about 80%, in accord with normal parameter of physiology. Contrastively, the average brain oxygen saturation of patients with heart function lack is 72.8%, which is obviously less than that of healthy persons and anaesthetised cases. The probability of medical statistics is less than 0.01. (2) The shapes of wave of brain blood and oxygen for the healthy person and the anaesthetised case reveal small periodical fluctuations with stable shape and base line, and the trend of increase or decrease of blood and oxygen parameters in brain tissue is synchronous and a phase reversal, but for the patient with heart function lack in a brain oxygen lack state, the shapes of wave are irregular. This is a hint that near infrared light passing through tissue can reflect the intuitionistic change of brain blood and oxygen parameters.(3) The power spectra of brain blood and oxygen for the healthy person and the anaesthetised case has a clear main peak, narrow bandwidth and perfect superposition each other, but the power spectra for the patient with heart function lack in a brain oxygen lack state is on the contrary.(4) The average cross correlation coefficient of brain blood and oxygen for healthy persons and anaesthetised cases is -0.9825±0.1027 close to -1. But the average cross correlation coefficient for patients with heart function lack in a brain oxygen lack state is merely -0.8923±0.1035 which is obviously greater than -1 and the probability of medical statistics is less than 0.01. The clinic experiments have proved that the shapes of waves, the power spectrum and cross correlation coefficient of brain blood and oxygen are useful to analyze the physiological status and changes of blood and oxygen in human brain.