Comparison of Pocket Pulse Oximeter and Standard Pulse Oximeter With ABG Analysis in Critically Ill Patients

Background: Pulse oximetry (SpO2) is a standard monitoring device in patients presenting to EMDs and intensive care units (ICUs). Pocket pulse oximeters (PPOs) are used widely in wards, EMDs, and small hospitals/clinics. These inexpensive PPOs also guide therapeutic interventions. Few studies have evaluated the accuracy of SpO2 in patients presenting to critical care areas vis-à-vis devices like PPO and standard pulse oximeter (SPO). This study becomes extremely relevant in view of the ongoing crisis of the COVID-19 pandemic wherein SpO2 monitoring is very important in hospitals, quarantine centers, small clinics, or even at home. Methods: Patients presenting to critical areas who underwent arterial blood gases (ABG) analysis on the recommendation of the treating physician between November 2016 and October 2018 were included in this study. Along with the ABG analysis, a simultaneous assessment of SpO2 was done with a single PPO and SPO and all values were noted. Statistical analysis was done using the SPSS v.21.0 for Windows. Results: The study included 300 patients. We compared the O2 saturations of ABG, SPO, and PPO with respect to sex, different age groups, and at different levels of ABG pCO2, HCO3, and pH in all patients. All parameters were compared using the Pearson’s correlation test; the results showed that ABG O2 saturations were closer to the SPO than the PPO but the differences were not statistically significant as the Pearson’s correlation values for all parameters were >0.8. We also compared the parameters by Bland Altman Plot and all observations were outside 95% CI (confidence interval), which means that there was a good agreement between O2 saturations by all three methods, that is, ABG, SPO, and PPO; however, ABG O2 saturations were closer to SPO than PPO but this difference was not statistically significant. Hence, we conclude that the PPO is a useful tool for reliable monitoring of O2 saturations. Conclusion: This study highlights that inexpensive and noninvasive PPO can be used as a standard monitoring device with reliability in critically ill patients presenting to EMDs, ICUs, and small hospitals/clinics, quarantine centers, and even at home.

Quantitative Changes in Muscular and Capillary Oxygen Desaturation Measured by Optical Sensors during Continuous Positive Airway Pressure Titration for Obstructive Sleep Apnea

Obstructive sleep apnea (OSA) is a common sleep disorder, and continuous positive airway pressure (CPAP) is the most effective treatment. Poor adherence is one of the major challenges in CPAP therapy. The recent boom of wearable optical sensors measuring oxygen saturation makes at-home multiple-night CPAP titrations possible, which may essentially improve the adherence of CPAP therapy by optimizing its pressure in a real-life setting economically. We tested whether the oxygen desaturations (ODs) measured in the arm muscle (arm_OD) by gold-standard frequency-domain multi-distance near-infrared spectroscopy (FDMD-NIRS) change quantitatively with titrated CPAP pressures in OSA patients together with polysomnography. We found that the arm_OD (2.08 ± 1.23%, mean ± standard deviation) was significantly smaller (p-value < 0.0001) than the fingertip OD (finger_OD) (4.46 ± 2.37%) measured by a polysomnography pulse oximeter. Linear mixed-effects models suggested that CPAP pressure was a significant predictor for finger_OD but not for arm_OD. Since FDMD-NIRS measures a mixture of arterial and venous OD, whereas a fingertip pulse oximeter measures arterial OD, our results of no association between arm_OD and finger_OD indicate that the arm_OD mainly represented venous desaturation. Arm_OD measured by optical sensors used for wearables may not be a suitable indicator of the CPAP titration effectiveness.

Evaluation of the performance of two new generation pulse oximeters in cats at different probe positions and under the influence of vasoconstriction

Objectives The aim of this study was to compare the failure rate of two new generation pulse oximeters at different probe positions, and with and without vasoconstriction, in anaesthetised cats. Methods This prospective clinical study included 103 cats in which the new generation pulse oximeters, the Rad-5 (Masimo) and EDAN H100N (EDAN), were evaluated. Premedication consisted of the vasoconstrictive drug combination butorphanol (0.2 mg/kg IV) and dexmedetomidine (5 µg/kg IV), or butorphanol only (0.2 mg/kg IV). Pulse oximeter failure rate at the tongue was compared between both groups. Pulse oximeter failure rate was also analysed at the alternative probe positions of the lip, pinna, knee fold and toe in the butorphanol group. Student’s t-test, Wilcoxon matched pairs signed rank test, Mann−Whitney U-test, Friedman test and χ2 test were performed. A P value <0.05 was considered to be statistically significant. Results Overall failure to achieve an adequate signal was 37.6% with the Masimo and 48.0% with the EDAN pulse oximeter ( P <0.0001). At the standard probe position on the tongue, the Masimo failed in 4.5%, while the EDAN failed in 35.3% ( P <0.0001). Vasoactive premedication increased the failure rate for the Masimo from 3.8% to 5.2% ( P = 0.3414) and for the EDAN from 22.4% to 49.0% ( P <0.0001). At the alternative probe positions of the lip and knee fold, failure rates for the Masimo were lower (39.7% and 81.4%) than with the EDAN (52.6% and 94.4%; P = 0.0231 and P = 0.0005, respectively), while the Masimo failed more often at the pinna (63.5%) than the EDAN (47.4%; P = 0.0044). At the alternative probe position of the toe, the failure rate for the Masimo (32.7%) was not different from the EDAN (38.5%; P = 0.7547). Conclusions and relevance The Masimo pulse oximeter had lower signal failure rates at the standard probe position on the tongue and at 2/4 alternative probe positions. The standard probe position on the tongue had the lowest failure rate for both devices. Dexmedetomidine-induced vasoconstriction increased the failure rate for the EDAN but not for the Masimo pulse oximeter.

Validation of a Wrist-Worn Reflectance Pulse Oximeter During Sleep and Prediction of Obstructive Sleep Apnea: A Proof-of-Concept Study (Preprint)

BACKGROUND Obstructive sleep apnea (OSA) is a common sleep disorder characterized by repetitive upper airway obstruction during sleep, thereby resulting in oxygen desaturation, frequent arousals, and increased sympathetic activity. Wearable devices that measure peripheral oxygen saturation have been developed for the screening of OSA. OBJECTIVE This study aimed to validate and characterize the estimation function of oxygen saturation measured by wrist-worn reflectance pulse oximetry during sleep and to predict the derived OSA using the oxygen desaturation index (ODI). METHODS Oxygen saturation was simultaneously measured using reflectance pulse oximetry from the Samsung Galaxy Watch 4 series (SM-R890N, SM-R860N, Samsung Electronics Co.; GW4) and transmittance pulse oximetry from polysomnography as a reference (SpO2Ref). The performance was evaluated by the root mean squared error (RMSE) and coverage rate, and it was compared according to the apnea-hypopnea index (AHI). The GW4-ODI was used to predict moderate to severe OSA. RESULTS A total of 97 adults (44.4 ± 13.0 years; men 76.3%, women 23.7%) participated in this study. Depending on the AHI, participants were classified as either normal (n=18), mild (n=21), moderate (n=23), or severe OSA (n=35). Wrist-worn reflectance pulse oximetry showed an overall RMSE of 2.3% and negligible bias of -0.2%. A Bland-Altman density plot showed good agreement of oxygen saturation between GW4 and the reference pulse oximeter. RMSEs were 1.65 ± 0.57%, 1.76 ± 0.65%, 1.93 ± 0.54%, and 2.93 ± 1.71% for normal, mild, moderate, and severe OSA, respectively. GW4-ODI ≥5/h had the highest predictive ability for moderate to severe OSA with a sensitivity of 89.7%, a specificity of 64.1%, an accuracy of 79.4%, and an area under the curve of 0.908 (95% CI, 0.852–0.963). CONCLUSIONS GW4 was successfully validated for measuring oxygen saturation with reflectance pulse oximetry during sleep. This study demonstrates the feasibility of GW4 for screening moderate to severe OSA.

Perfusion Index as an Indicator for Mortality in Children with Plasmodium falciparum Severe Malaria

Background:Severe malaria (SM) remains a major global health problem causing ~275,000 pediatric deaths annually, worldwide. Continuous, non-invasive monitoring of peripheral perfusion can help detect abnormalities in systemic circulation, a common problem in critically ill patients, and can improve outcomes in children hospitalized with SM. Perfusion index (PI), an indicator of peripheral perfusion measured using a point-of-care pulse oximeter, is the ratio of pulsatile blood flow to static blood in peripheral tissue. Objective: To investigate the role of PI as an indicator of adverse outcomes including mortality in children hospitalized with SM. Methods: We measured PI in a prospective cohort study of 600 children <5 years of age with 5 different clinical manifestations of SM, and 120 healthy community children (CC) at two hospitals in Uganda. PI was measured at 6-hr intervals during hospitalization using a Masimo Rad 57 pulse oximeter. Results: Children with SM had significantly lower admission PI values (1.2 [IQR: 0.58, 2.2] compared to CC (2.8 [1.7, 4.3], p<0.001). Children with SM manifesting as respiratory distress syndrome or severe malarial anemia had lower median PI compared to other manifestations including cerebral malaria, the deadliest form of SM in children. In children with SM, a log decrease in admission PI was associated with 2.7 higher odds of in-hospital mortality (p=0.01). A log reduction in PI was also associated with in-hospital clinical complications associated with SM, including circulatory shock, deep acidotic breathing and acidosis, hypoglycemia, and severe anemia (all P<0.03). In survivors of SM, there were no significant associations between PI and cognitive outcomes at 12-month follow-up. Conclusion: The role of PI as an indicator of mortality in children with SM and the use of point-of-care tools for continuous monitoring of PI warrants further investigation in the management of SM to prevent or reduce the incidence of adverse outcomes.

High Concentration Oxygen and Hypercapnia in Respiratory Disease

<p>Oxygen-induced elevations in arterial carbon dioxide tension have been demonstrated in patients with chronic obstructive pulmonary disease (COPD), asthma, pneumonia, obesity hypoventilation syndrome (OHS) and acute lung injury. A randomised controlled trial (RCT) in acute exacerbations of COPD (AECOPD) found an over two-fold increase in mortality in patients randomised to high concentration oxygen, compared to titrated oxygen. These findings support guideline recommendations for titration of oxygen therapy to a target oxygen saturation range, reducing the risks of hypoxaemia and hyperoxaemia. This thesis focuses on the potential implications of oxygen-induced elevations in carbon dioxide in the acute clinical setting. The reviews and studies in the following chapters are all aimed at addressing gaps in knowledge which may have practical implications for oxygen therapy and/or the identification of patients at risk of oxygen-induced hypercapnia in clinical practice. Numerous studies have demonstrated that high concentration oxygen continues to be administered to acutely unwell patients, despite guideline recommendations for titrated therapy. The first study in this thesis is a clinical audit evaluating the effects of a staff education program, which included face-to-face and written training for ambulance staff. The education program was associated with reduced the rates of high concentration oxygen administration to patients with AECOPD. This suggests active education may increase adherence to oxygen guidelines among clinical staff. The ability to avoid hypoxaemia and hyperoxaemia during titrated oxygen therapy relies on appropriate lower and upper target oxygen saturation limits, which may be impacted on by pulse oximeter accuracy. The second study in this thesis is a multicentre observational study in which 400 paired pulse oximeter (SpO₂) and arterial blood gas saturation (SaO₂) values were collected in the hospital setting. A SpO₂ <92% had 100% sensitivity for detecting SaO₂<90%. This indicates guideline recommended target oxygen saturations of 92-96% adequately avoid hypoxaemia. Two studies in OHS patients have investigated the effects of oxygen administration on carbon dioxide, however their designs, including recruitment of stable participants, have limited their generalisability to clinical practice. Therefore, a cross over RCT was conducted in 24 morbidly obese hospital inpatients, randomised to the order they received high concentration and titrated oxygen, each for 60 minutes. The mean change in the transcutaneous partial pressure of carbon dioxide (PtCO₂) from baseline was 3.2 mmHg higher during high concentration oxygen, compared with titrated oxygen (P=0.002). This supports guideline recommendations to titrate oxygen in patients with obesity, regardless of whether they have a diagnosis of OHS or not. The effects of oxygen in patients with bronchiectasis, neuromuscular disease or kyphoscoliosis are uncertain. Stable patients with these conditions were recruited to double-blind randomised cross over trials administering air and 50% oxygen, each for 30 minutes. A trial was also performed in stable COPD patients for comparison. There was no significant change in PtCO₂ with oxygen therapy in the neuromuscular disease/kyphoscoliosis patients. In the bronchiectasis and COPD patients, oxygen was associated with increased PtCO₂ from baseline compared to air, but the differences were not clinically significant (0.4 mmHg, P=0.012 and 1.3 mmHg, P<0.001, respectively). The lack of a clinically significant PtCO₂ increase in the COPD patients indicated the study findings were unlikely to be generalisable to the clinical setting, and highlights the potential limitations in applying data from stable participants to patients who require acute oxygen therapy. These studies support current guideline recommendations for titrated oxygen therapy, provide insight into the limits of studying the effects of oxygen in stable participants, and demonstrate the utility of an educational program to aid the translation of research findings into relevant changes in clinical practice.</p>

High Concentration Oxygen and Hypercapnia in Respiratory Disease

<p>Oxygen-induced elevations in arterial carbon dioxide tension have been demonstrated in patients with chronic obstructive pulmonary disease (COPD), asthma, pneumonia, obesity hypoventilation syndrome (OHS) and acute lung injury. A randomised controlled trial (RCT) in acute exacerbations of COPD (AECOPD) found an over two-fold increase in mortality in patients randomised to high concentration oxygen, compared to titrated oxygen. These findings support guideline recommendations for titration of oxygen therapy to a target oxygen saturation range, reducing the risks of hypoxaemia and hyperoxaemia. This thesis focuses on the potential implications of oxygen-induced elevations in carbon dioxide in the acute clinical setting. The reviews and studies in the following chapters are all aimed at addressing gaps in knowledge which may have practical implications for oxygen therapy and/or the identification of patients at risk of oxygen-induced hypercapnia in clinical practice. Numerous studies have demonstrated that high concentration oxygen continues to be administered to acutely unwell patients, despite guideline recommendations for titrated therapy. The first study in this thesis is a clinical audit evaluating the effects of a staff education program, which included face-to-face and written training for ambulance staff. The education program was associated with reduced the rates of high concentration oxygen administration to patients with AECOPD. This suggests active education may increase adherence to oxygen guidelines among clinical staff. The ability to avoid hypoxaemia and hyperoxaemia during titrated oxygen therapy relies on appropriate lower and upper target oxygen saturation limits, which may be impacted on by pulse oximeter accuracy. The second study in this thesis is a multicentre observational study in which 400 paired pulse oximeter (SpO₂) and arterial blood gas saturation (SaO₂) values were collected in the hospital setting. A SpO₂ <92% had 100% sensitivity for detecting SaO₂<90%. This indicates guideline recommended target oxygen saturations of 92-96% adequately avoid hypoxaemia. Two studies in OHS patients have investigated the effects of oxygen administration on carbon dioxide, however their designs, including recruitment of stable participants, have limited their generalisability to clinical practice. Therefore, a cross over RCT was conducted in 24 morbidly obese hospital inpatients, randomised to the order they received high concentration and titrated oxygen, each for 60 minutes. The mean change in the transcutaneous partial pressure of carbon dioxide (PtCO₂) from baseline was 3.2 mmHg higher during high concentration oxygen, compared with titrated oxygen (P=0.002). This supports guideline recommendations to titrate oxygen in patients with obesity, regardless of whether they have a diagnosis of OHS or not. The effects of oxygen in patients with bronchiectasis, neuromuscular disease or kyphoscoliosis are uncertain. Stable patients with these conditions were recruited to double-blind randomised cross over trials administering air and 50% oxygen, each for 30 minutes. A trial was also performed in stable COPD patients for comparison. There was no significant change in PtCO₂ with oxygen therapy in the neuromuscular disease/kyphoscoliosis patients. In the bronchiectasis and COPD patients, oxygen was associated with increased PtCO₂ from baseline compared to air, but the differences were not clinically significant (0.4 mmHg, P=0.012 and 1.3 mmHg, P<0.001, respectively). The lack of a clinically significant PtCO₂ increase in the COPD patients indicated the study findings were unlikely to be generalisable to the clinical setting, and highlights the potential limitations in applying data from stable participants to patients who require acute oxygen therapy. These studies support current guideline recommendations for titrated oxygen therapy, provide insight into the limits of studying the effects of oxygen in stable participants, and demonstrate the utility of an educational program to aid the translation of research findings into relevant changes in clinical practice.</p>

Covid Patient Health Monitoring Using IoT During Quarantine

The term “COVID” is breaking the hearts of the entire human community. The Corona virus is more infectious and is exceptionally irresistible, it is vital to isolate the patients and yet the specialists need to screen Corona virus patients as well. With the expanding increase in the number of Corona cases, the doctors find it difficult to keep track on the medical issue of isolated patients. To address this issue, we designed a distant IOT based screen framework, that considers observing of numerous Corona virus patients over the web. The system uses temperature sensor, respiratory sensor and pulse oximeter to measure the health parameters of the patients. If any oddity is detected in patient’s health, the patient presses the emergency help button which we installed in our system. This will alert the doctor and the care taker over IOT remotely. Our system thus provides a safe health monitoring design, in order to prevent the disease spreading through Corona virus and monitoring the individual health of each patient.