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1.
Scand J Clin Lab Invest ; 82(4): 334-340, 2022 Jul.
Article in English | MEDLINE | ID: mdl-35767233

ABSTRACT

BACKGROUND: Improving tissue perfusion can improve clinical outcomes in surgical patients, where monitoring may aid clinicians in detecting adverse conditions and guide interventions. Transcutaneous monitoring (TCM) of oxygen (tcpO2) and carbon dioxide (tcpCO2) is a well-proven technology and could potentially serve as a measure of local circulation, perfusion and metabolism, but the clinical use is not thoroughly explored. The purpose of this proof-of-concept study was to investigate whether TCM of blood gasses could detect changes in perfusion during major vascular surgery. METHODS: Ten patients with peripheral arterial disease scheduled for lower limb major arterial revascularization under general anaesthesia were consecutively included. TcpO2 and tcpCO2 were continuously recorded from anaesthesia induction until skin closure with a TCM monitor placed on both legs and the thorax. Peripheral oxygen saturation was kept ≥94% and mean arterial blood pressure ≥65 mmHg. The primary outcomes were changes in tcpO2 and tcpCO2 related to arterial clamping and declamping during the procedure and analyzed by paired statistics. RESULTS: Femoral artery clamping resulted in a significant decrease in tcpO2 (-2.1 kPa, IQR-4.2; -0.8), p=.017)), followed by a significant increase in response to arterial declamping (5.5 kPa, IQR 0-7.3), p=.017)). Arterial clamping resulted in a statistically significant increase in tcpCO2 (0.9 kPa, IQR 0.3-5.4), p=.008)) and a significant decrease following declamping (-0.7 kPa, IQR -2.6; -0.2), p=.011)). CONCLUSION: Transcutaneous monitoring of oxygen and carbon dioxide is a feasible method for detection of extreme changes in tissue perfusion during arterial clamping and declamping, and its use for improving patient outcomes should be explored. Clinical Trials identifier: NCT04040478. Registered on July 31, 2019.


Subject(s)
Blood Gas Monitoring, Transcutaneous , Carbon Dioxide , Blood Gas Monitoring, Transcutaneous/methods , Endarterectomy , Femoral Artery/surgery , Humans , Oxygen , Perfusion
3.
Altern Ther Health Med ; 28(3): 24-29, 2022 Mar.
Article in English | MEDLINE | ID: mdl-35325872

ABSTRACT

Objective: The aim of this study was to investigate the effects of different oxygen delivery methods during noninvasive positive-pressure ventilation (NPPV) on transcutaneous oxygen pressure (PtcO2), transcutaneous carbon dioxide pressure (PtcCO2) and fraction of inspired oxygen (FiO2) in order to find more effective oxygen delivery methods. Methods: A total of 20 healthy volunteers participated in this study, all of whom received NPPV. All volunteers received oxygen through a nasal cannula (NC) located in a mask or through a mask alone (OSTM) (oxygen flow rate was 3L/min and 5L/min), PtcO2 and PtcCO2 were measured, and the effects of the 2 methods of oxygen concentration on PtcO2 and PtcCO2 levels were evaluated during noninvasive ventilation. Then, the additional oxygen concentration was stopped, oxygen was delivered through the ventilator, and the oxygen concentration was adjusted so that the PtcO2 reached the same oxygen concentration level as noted through the NC or OSTM. This concentration of oxygen indirectly reflects FiO2 in different oxygen delivery methods. Results: When NPPV was used under the same pressure, FiO2 increased from 44.4% to 65.3% when oxygen was delivered through an NC compared with oxygen supplied by OSTM alone. PtcO2 was also significantly increased from 18.9% to 24.9%; the difference was significant (P < .05), while there was no significant change in PtcCO2 (P > .05). Conclusion: When NPPV is used, an NC can obviously improve FiO2 and PtcO2 without increasing PtcCO2. It can save oxygen and is more suitable for NPPV during an emergency and for home use.


Subject(s)
Noninvasive Ventilation , Blood Gas Monitoring, Transcutaneous , Carbon Dioxide , Humans , Oxygen , Positive-Pressure Respiration/methods
4.
Eur J Vasc Endovasc Surg ; 63(5): 707-713, 2022 05.
Article in English | MEDLINE | ID: mdl-35283001

ABSTRACT

OBJECTIVE: It was hypothesised that there is a linear relationship between the severity of exercise induced calf ischaemia and the prevalence of calf claudication on a treadmill until a plateau is reached. It was expected that no pain would be present in the absence of ischaemia and all severely ischaemic calves would be symptomatic. METHODS: This was a retrospective analysis of a cross sectional acquired database recording. Transcutaneous oxygen pressure (TcPO2) on the chest and on each calf was used to evaluate calf ischaemia during treadmill tests with simultaneous recording of calf pain in 7 884 subjects (15 768 calves). The minimum value of calf changes from rest minus chest changes from rest (DROPm) was calculated. Regression analyses were used to determine the correlation between the proportion of exercise induced symptoms present in the calves and each unit of DROPm values. Analysis was repeated after objective determination of the cutoff point between the linear increase and the plateau. RESULTS: A linear relationship was found between the degree of ischaemia and the proportion of symptomatic calves for DROPm values ranging from 0 mmHg to -28 mmHg (proportion = -0.014 × DROPm + 0.32, r = 0.961, p <.001). For DROPm values lower than -28 mmHg (severe ischaemia), on average one of three limbs remained asymptomatic. The biphasic relationship between DROPm and prevalence of symptoms persists after exclusion of patients with diabetes mellitus, exercise induced hypoxaemia, and no evidence of lower extremity arterial disease (LEAD). CONCLUSION: The relationship between exercise induced pain and ischaemia is biphasic with a linear increase in the proportion of symptomatic limbs with ischaemia severity, until a plateau is reached for the more severely ischaemic limbs. The presence of exercise related calf symptoms should not automatically be reported as indicating the presence of LEAD; and the absence of exercise induced symptoms is not proof that ischaemia does not occur during exercise.


Subject(s)
Blood Gas Monitoring, Transcutaneous , Exercise Test , Animals , Cattle , Cross-Sectional Studies , Humans , Intermittent Claudication/diagnosis , Intermittent Claudication/epidemiology , Ischemia/diagnosis , Ischemia/epidemiology , Pain , Prevalence , Retrospective Studies
5.
Respir Physiol Neurobiol ; 300: 103869, 2022 06.
Article in English | MEDLINE | ID: mdl-35181538

ABSTRACT

Despite potentially life-threatening symptoms of disordered breathing in severe cerebral illness, there are no clear recommendations on diagnostic and therapeutic strategies for these patients. To identify types of breathing disorders observed in severely neurological comprised patients, to direct further research on classification, pathophysiology, diagnosis and treatment for disordered breathing in cerebral disease. Data including polygraphy, transcutaneous capnometry, blood gas analysis and radiological examinations of patients with severe cerebral illness and disordered breathing admitted to the neurological intensive care were analyzed. Patients (15) presented with acquired central hypoventilation syndrome (ACHS), central bradypnea, central tachypnea, obstructive, mixed and central apneas and hypopneas, Cheyne Stokes respiration, ataxic (Biot's) breathing, cluster breathing and respiration alternans. Severe cerebral illness may result in an ACHS and in a variety of disorders of the respiratory rhythm. Two of these, abrupt switches between breathing patterns and respiration alternans, suggest the existence of a rhythmogenic respiratory network. Polygraphy, transcutaneous capnometry, blood gas analysis and MRI are promising tools for diagnosis and research alike.


Subject(s)
Cheyne-Stokes Respiration , Sleep Apnea, Central , Blood Gas Monitoring, Transcutaneous , Cheyne-Stokes Respiration/therapy , Humans , Respiration , Sleep Apnea, Central/therapy
6.
Sleep Med ; 90: 9-16, 2022 02.
Article in English | MEDLINE | ID: mdl-35051737

ABSTRACT

INTRODUCTION: There is a general underappreciation of the spectrum of obesity-related breathing disorders and their consequences. We therefore compared characteristics of obese patients with eucapnic obstructive sleep apnea (OSA), OSA with obesity-related sleep hypoventilation (ORSH) or obesity hypoventilation syndrome (OHS) to identify the major determinants of hypoventilation. PATIENTS AND METHODS: In this prospective, diagnostic study (NCT04570540), obese patients with OSA, ORSH or OHS were characterized applying polysomnography with transcutaneous capnometry, blood gas analyses, bodyplethysmography and measurement of hypercapnic ventilatory response (HCVR). Pathophysiological variables known to contribute to hypoventilation and differing significantly between the groups were specified as potential independent variables in a multivariable logistic regression to identify major determinants of hypoventilation. RESULTS: Twenty, 43 and 19 patients were in the OSA, ORSH and OHS group, respectively. BMI was significantly lower in OSA as compared to OHS. The extent of SRBD was significantly higher in OHS as compared to OSA or ORSH. Patients with ORSH or OHS showed a significantly decreased forced expiratory volume in 1 s and forced vital capacity compared to OSA. HCVR was significantly lower in OHS and identified as the major determinant of hypoventilation in a multivariable logistic regression (Nagelkerke R2 = 0.346, p = 0.050, odds ratio (95%-confidence interval) 0.129 (0.017-1.004)). CONCLUSION: Although there were differences in BMI, respiratory mechanics and severity of upper airway obstruction between groups, our data support HCVR as the major determinant of obesity-associated hypoventilation.


Subject(s)
Obesity Hypoventilation Syndrome , Blood Gas Monitoring, Transcutaneous , Body Mass Index , Cross-Sectional Studies , Humans , Obesity/complications , Obesity Hypoventilation Syndrome/complications , Obesity Hypoventilation Syndrome/diagnosis , Prospective Studies
7.
Sensors (Basel) ; 22(1)2021 Dec 28.
Article in English | MEDLINE | ID: mdl-35009731

ABSTRACT

Carbon dioxide (CO2) monitoring in human subjects is of crucial importance in medical practice. Transcutaneous monitors based on the Stow-Severinghaus electrode make a good alternative to the painful and risky arterial "blood gases" sampling. Yet, such monitors are not only expensive, but also bulky and continuously drifting, requiring frequent recalibrations by trained medical staff. Aiming at finding alternatives, the full panel of CO2 measurement techniques is thoroughly reviewed. The physicochemical working principle of each sensing technique is given, as well as some typical merit criteria, advantages, and drawbacks. An overview of the main CO2 monitoring methods and sites routinely used in clinical practice is also provided, revealing their constraints and specificities. The reviewed CO2 sensing techniques are then evaluated in view of the latter clinical constraints and transcutaneous sensing coupled to a dye-based fluorescence CO2 sensing seems to offer the best potential for the development of a future non-invasive clinical CO2 monitor.


Subject(s)
Blood Gas Monitoring, Transcutaneous , Carbon Dioxide , Electrodes , Humans , Monitoring, Physiologic , Research Subjects
8.
Front Endocrinol (Lausanne) ; 12: 744195, 2021.
Article in English | MEDLINE | ID: mdl-34956078

ABSTRACT

Background: All diagnostic procedures of peripheral arterial disease (PAD) in diabetic foot (DF) are complicated due to diabetes mellitus and its late complications.The aim of our study is to enhance diagnosis of PAD using a novel transcutaneous oximetry (TcPO2) stimulation test. Methods: The study comprised patients with mild-to-moderate PAD(WIfI-I 1 or 2) and baseline TcPO2 values of 30-50 mmHg.TcPO2 was measured across 107 different angiosomes. Stimulation examination involved a modification of the Ratschow test. All patients underwent PAD assessment (systolic blood pressures (SBP), toe pressures (TP), the ankle-brachial indexes (ABI) and toe-brachial indexes (TBI), duplex ultrasound of circulation). Angiosomes were divided into two groups based on ultrasound findings: group M(n=60) with monophasic flow; group T(n=47) with triphasic flow. Large vessel parameters and TcPO2 at rest and after exercise (minimal TcPO2, changes in TcPO2 from baseline (Δ,%), TcPO2 recovery time) measured during the stimulation test were compared between study groups. Results: During the TcPO2 stimulation exercise test, group M exhibited significantly lower minimal TcPO2 (26.2 ± 11.1 vs. 31.4 ± 9.4 mmHg; p<0.01), greater Δ and percentage decreases from resting TcPO2 (p=0.014 and p=0.007, respectively) and longer TcPO2 recovery times (446 ± 134 vs. 370 ± 81ms;p=0.0005) compared to group T. SBPs, TPs and indexes were significantly lower in group M compared to group T. Sensitivity and specificity of TcPO2 stimulation parameters during PAD detection increased significantly to the level of SBP, ABI, TP and TBI. Conclusion: Compared to resting TcPO2, TcPO2 measured during stimulation improves detection of latent forms of PAD and restenosis/obliterations of previously treated arteries in diabetic foot patients. Clinical Trial Registration: ClinicalTrials.gov [https://register.clinicaltrials.gov/prs/app/action/SelectProtocol?sid=S0009V7W&selectaction=Edit&uid=U0005381&ts=2&cx=3j24u2], identifier NCT04404699.


Subject(s)
Blood Gas Monitoring, Transcutaneous/methods , Diabetic Foot/complications , Peripheral Arterial Disease/diagnosis , Peripheral Arterial Disease/etiology , Aged , Aged, 80 and over , Ankle Brachial Index , Blood Pressure , Diabetic Foot/diagnostic imaging , Exercise/physiology , Female , Humans , Lower Extremity/blood supply , Male , Middle Aged , Peripheral Arterial Disease/diagnostic imaging , Regional Blood Flow , Toes/blood supply , Ultrasonography, Doppler, Duplex
9.
Annu Int Conf IEEE Eng Med Biol Soc ; 2021: 7132-7135, 2021 11.
Article in English | MEDLINE | ID: mdl-34892745

ABSTRACT

New types of miniaturized biomedical devices transform contemporary diagnostic and therapeutic techniques in medicine. This evolution has demonstrated exceptional promise in providing infrastructures for enabling precision health by creating diverse sensing modalities. To this end, this paper presents a prototype for transcutaneous carbon dioxide monitoring to diversify the measurable critical parameters for human health. Transcutaneous carbon dioxide monitoring is a noninvasive, surrogate method of assessing the partial pressure of carbon dioxide in the blood. The partial pressure of carbon dioxide is a vital index that can help understand momentarily changing ventilation trends. Therefore, it needs to be reported continuously to monitor the ventilatory status of critically ill patients. The proposed prototype employs an infrared LED as the excitation source. The infrared emission, which decreases in response to an increasing carbon dioxide concentration, is applied to a thermopile sensor that can detect the infrared intensity variations precisely. We have measured the changes in the partial pressure of carbon dioxide in the range of 0-120 mmHg, which covers humans' typical values, 35-45 mmHg. The prototype occupies an area of 25 cm2 (50 mm × 50 mm) and consumes 85 mW power.


Subject(s)
Blood Gas Monitoring, Transcutaneous , Carbon Dioxide , Critical Illness , Humans , Monitoring, Physiologic , Partial Pressure
10.
Paediatr Anaesth ; 32(3): 429-435, 2022 Mar.
Article in English | MEDLINE | ID: mdl-34882905

ABSTRACT

BACKGROUND: Arterial blood gas analysis is the gold standard for monitoring of Pa CO2 and PaO2 during mechanical ventilation. However, continuous measurements would be preferred. Transcutaneous sensors continuously measure blood gases diffusing from the locally heated skin. These sensors have been validated in children mostly in intensive care settings. Accuracy in children during general anesthesia is largely unknown. AIMS: We conducted a study in children undergoing general anesthesia to validate the use and to determine the accuracy of continuous transcutaneous measurements of the partial pressures of PCO2 (tcPCO2 ) and PO2 (tcPO2 ). METHODS: A prospective observational study in a tertiary care pediatric hospital in The Netherlands, from April to October 2018, in children aged 0-18 years undergoing general anesthesia. Patients were included when endotracheally intubated and provided with an arterial catheter for regular blood sampling. Patients with a gestational age <31 weeks, burn victims, and patients with skin disease were excluded. TcPCO2 and tcPO2  measurements were performed with a SenTec OxiVenT™ sensor (SenTec AG). Accuracy was determined with an agreement analysis between arterial and transcutaneous PCO2 and PO2  values, and between arterial and endtidal PCO2 (etCO2 ) values, according to Bland and Altman, accounting for multiple measurements per subject. RESULTS: We included 53 patients (median age 4.1 years, IQR 0.7-14.4 years) and retrieved 175 samples. TcPCO2 -Pa CO2 agreement analysis provided a bias of 0.06 kPa (limits of agreement (LOA) -1.18 to 1.31), the etCO2 -Pa CO2 agreement showed a bias of -0.31 kPa (LOA -1.38 to 0.76). Results of the tcPO2 -PaO2 agreement showed a bias of 3.40 to 0.86* (mean tension) kPa. CONCLUSIONS: This study showed good agreement between Pa CO2 and tcPCO2 in children of all ages during general anesthesia. Both transcutaneous and endtidal CO2  measurements showed good accuracy. TcPO2 is only accurate under 6 months of age.


Subject(s)
Blood Gas Monitoring, Transcutaneous , Carbon Dioxide , Anesthesia, General , Blood Gas Monitoring, Transcutaneous/methods , Child , Child, Preschool , Critical Care , Humans , Respiration, Artificial
11.
Nitric Oxide ; 119: 1-8, 2022 02 01.
Article in English | MEDLINE | ID: mdl-34871799

ABSTRACT

In heart failure with reduced ejection fraction (HFrEF), nitric oxide-soluble guanylyl cyclase (sGC) pathway dysfunction impairs skeletal muscle arteriolar vasodilation and thus capillary hemodynamics, contributing to impaired oxygen uptake (V̇O2) kinetics. Targeting this pathway with sGC activators offers a new treatment approach to HFrEF. We tested the hypotheses that sGC activator administration would increase the O2 delivery (Q̇O2)-to-V̇O2 ratio in the skeletal muscle interstitial space (PO2is) of HFrEF rats during twitch contractions due, in part, to increases in red blood cell (RBC) flux (fRBC), velocity (VRBC), and capillary hematocrit (Hctcap). HFrEF was induced in male Sprague-Dawley rats via myocardial infarction. After 3 weeks, rats were treated with 0.3 mg/kg of the sGC activator BAY 60-2770 (HFrEF + BAY; n = 11) or solvent (HFrEF; n = 9) via gavage b.i.d for 5 days prior to phosphorescence quenching (PO2is, in contracting muscle) and intravital microscopy (resting) measurements in the spinotrapezius muscle. Intravital microscopy revealed higher fRBC (70 ± 9 vs 25 ± 8 RBC/s), VRBC (490 ± 43 vs 226 ± 35 µm/s), Hctcap (16 ± 1 vs 10 ± 1%) and a greater number of capillaries supporting flow (91 ± 3 vs 82 ± 3%) in HFrEF + BAY vs HFrEF (all P < 0.05). Additionally, PO2is was especially higher during 12-34s of contractions in HFrEF + BAY vs HFrEF (P < 0.05). Our findings suggest that sGC activators improved resting Q̇O2 via increased fRBC, VRBC, and Hctcap allowing for better Q̇O2-to-V̇O2 matching during the rest-contraction transient, supporting sGC activators as a potential therapeutic to target skeletal muscle vasomotor dysfunction in HFrEF.


Subject(s)
Benzoates/pharmacology , Biphenyl Compounds/pharmacology , Capillaries/metabolism , Heart Failure/blood , Hydrocarbons, Fluorinated/pharmacology , Muscle, Skeletal/metabolism , Oxygen/metabolism , Soluble Guanylyl Cyclase/metabolism , Animals , Blood Gas Monitoring, Transcutaneous , Hemodynamics , Male , Rats, Sprague-Dawley
12.
Int Angiol ; 41(1): 82-89, 2022 Feb.
Article in English | MEDLINE | ID: mdl-34825799

ABSTRACT

BACKGROUND: Adequate tissue perfusion is an important prognostic and diagnostic factor during the management of lower limb peripheral arterial disease. Convenient and real-time tissue perfusion monitoring remains an elusive challenge. METHODS: Tissue perfusion on the dorsal and plantar surfaces of both feet of 20 participants was measured during and after cuff-induced ischemia using a novel 4-channel, laser-based perfusion monitoring device based on diffuse speckle contrast analysis technology (Pedra sensors). Participants were free of significant peripheral arterial disease. Transcutaneous partial pressure of oxygen (TcPO2) measurements were recorded concurrently for comparison. RESULTS: Pedra sensors detected perfusion changes significantly more quickly than TcPO2 sensors. One minute after induced ischemia, the mean percent changes from baseline values (before ischemia) were -22.7±32.0% and -3.1±8.8% (P<0.001) for Pedra and TcPO2 sensors, respectively. One minute into induced ischemia, Pedra sensors had reached 50.5% of the 5-minute ischemia reading whereas TcPO2 sensors had reached only 18.6% of the 5-minute reading (P=0.046). Pedra sensors reported hyperemia immediately after cuff release with a mean percent change from baseline of 143.8±122.3%/173.4±121.8% on the dorsal/plantar surfaces while TcPO2 measurements were still recording negative changes at that time (-26.7±19.4%/-18.6±24.4% dorsal/plantar). Pedra sensors exhibited markedly lower interobserver and intraobserver variability than TcPO2 sensors. CONCLUSIONS: A device based on diffuse speckle contrast analysis reported tissue perfusion in real time. Cuff-induced ischemia and hyperemia following cuff release were rapidly and consistently detected on both the dorsal and plantar surfaces of the foot. Diffuse speckle contrast analysis may have value for real-time perfusion monitoring during angiography procedures.


Subject(s)
Blood Gas Monitoring, Transcutaneous , Peripheral Arterial Disease , Feasibility Studies , Humans , Ischemia/diagnosis , Perfusion , Peripheral Arterial Disease/diagnostic imaging
13.
Zhongguo Dang Dai Er Ke Za Zhi ; 23(8): 809-813, 2021 Aug 15.
Article in English, Chinese | MEDLINE | ID: mdl-34511170

ABSTRACT

OBJECTIVES: To evaluate the accuracy and safety of measurements of transcutaneous carbon dioxide partial pressure (TcPCO2) and transcutaneous oxygen partial pressure (TcPO2) at electrode temperatures lower than the value used in clinical practice in very low birth weight infants. METHODS: A total of 45 very low birth weight infants were enrolled. TcPCO2 and TcPO2 measurements were performed in these infants. Two transcutaneous monitors were placed simultaneously for each subject. One electrode was set and maintained at 42℃ used in clinical practice for neonates (control group), and the other was successively set at 38℃, 39℃, 40°C, and 41℃ (experimental group). The paired t-test was used to compare the measurement results between the groups. A Pearson correlation analysis was used to analyze the correlation between the measurement results of the experimental group and control group, and between the measurement results of experimental group and arterial blood gas parameters. RESULTS: There was no significant difference in TcPCO2 between each experimental subgroup (38-41℃) and the control group. TcPCO2 in each experimental subgroup (38-41℃) was strongly positively correlated with TcPCO2 in the control group (r>0.9, P<0.05) and arterial carbon dioxide partial pressure (r>0.8, P<0.05). There were significant differences in TcPO2 between each experimental subgroup (38-41℃) and the control group (P<0.05), but TcPO2 in each experimental subgroup (38-41℃) was positively correlated with TcPO2 in the control group (r=0.493-0.574, P<0.05) and arterial oxygen partial pressure (r=0.324-0.399, P<0.05). No skin injury occurred during transcutaneous measurements at all electrode temperatures. CONCLUSIONS: Lower electrode temperatures (38-41℃) can accurately measure blood carbon dioxide partial pressure in very low birth weight infants, and thus can be used to replace the electrode temperature of 42°C. Transcutaneous measurements at the lower electrode temperatures may be helpful for understanding the changing trend of blood oxygen partial pressure.


Subject(s)
Blood Gas Monitoring, Transcutaneous , Carbon Dioxide , Electrodes , Humans , Infant , Infant, Newborn , Infant, Very Low Birth Weight , Oxygen , Partial Pressure , Temperature
14.
Sensors (Basel) ; 21(16)2021 Aug 21.
Article in English | MEDLINE | ID: mdl-34451079

ABSTRACT

In the field of respiratory clinical practice, the importance of measuring carbon dioxide (CO2) concentrations cannot be overemphasized. Within the body, assessment of the arterial partial pressure of CO2 (PaCO2) has been the gold standard for many decades. Non-invasive assessments are usually predicated on the measurement of CO2 concentrations in the air, usually using an infrared analyzer, and these data are clearly important regarding climate changes as well as regulations of air quality in buildings to ascertain adequate ventilation. Measurements of CO2 production with oxygen consumption yield important indices such as the respiratory quotient and estimates of energy expenditure, which may be used for further investigation in the various fields of metabolism, obesity, sleep disorders, and lifestyle-related issues. Measures of PaCO2 are nowadays performed using the Severinghaus electrode in arterial blood or in arterialized capillary blood, while the same electrode system has been modified to enable relatively accurate non-invasive monitoring of the transcutaneous partial pressure of CO2 (PtcCO2). PtcCO2 monitoring during sleep can be helpful for evaluating sleep apnea syndrome, particularly in children. End-tidal PCO2 is inferior to PtcCO2 as far as accuracy, but it provides breath-by-breath estimates of respiratory gas exchange, while PtcCO2 reflects temporal trends in alveolar ventilation. The frequency of monitoring end-tidal PCO2 has markedly increased in light of its multiple applications (e.g., verify endotracheal intubation, anesthesia or mechanical ventilation, exercise testing, respiratory patterning during sleep, etc.).


Subject(s)
Blood Gas Monitoring, Transcutaneous , Pulmonary Medicine , Carbon Dioxide , Child , Humans , Partial Pressure , Respiration, Artificial
15.
Ann Vasc Surg ; 77: 127-131, 2021 Nov.
Article in English | MEDLINE | ID: mdl-34437955

ABSTRACT

OBJECTIVES: A novel approach in the evaluation of peripheral arterial disease is the photo-optical oxygen tension measurement (pTCpO2). This modality is suggested to be more practical in use in comparison to standard electro-chemical oxygen tension measurement. Hence, pTCpO2 might be of added value to evaluate revascularization of the lower extremities peri-procedural. We conducted a preliminary feasibility study to analyze the potential of pTCpO2 during revascularization. METHODS: Ten patients scheduled for revascularization of the lower extremities were enrolled. pTCpO2 values of the affected lower extremity were measured pre-operatively, during revascularization and after revascularization. Results were compared to the pre- and postoperative ankle-brachial index (ABI) and to perioperative angiography. Primary endpoint was the feasibility of perioperative pTCpO2 measurement. Secondary endpoints were concordance between pTCpO2, ABI, angiography and clinical outcome. RESULTS: Two out of twelve measurements were unsuccessful. Eight out of ten patients experienced significant clinical improvement and pTCpO2 increase. Two patients that did not experience clinical improvement corresponded with no changes in intraoperative angiography and without increase in ABI or pTCpO2. A significant and strong correlation was found between prior and after revascularization ABI and pTCpO2 measurements (r = 0.82 P = 0.04). CONCLUSIONS: Photo-optical transcutaneous oxygen tension measurement may serve as an intraoperative tool to evaluate the success of revascularization. pTCpO2 could be an alternative for the ABI to determine the success of lower extremity revascularization.


Subject(s)
Blood Gas Monitoring, Transcutaneous/instrumentation , Endovascular Procedures , Lower Extremity/blood supply , Optical Devices , Peripheral Arterial Disease/therapy , Photometry/instrumentation , Aged , Angiography , Ankle Brachial Index , Endovascular Procedures/adverse effects , Feasibility Studies , Female , Humans , Male , Middle Aged , Peripheral Arterial Disease/blood , Peripheral Arterial Disease/diagnosis , Peripheral Arterial Disease/physiopathology , Predictive Value of Tests , Time Factors , Treatment Outcome
16.
Anesth Analg ; 133(5): 1132-1137, 2021 11 01.
Article in English | MEDLINE | ID: mdl-34427566

ABSTRACT

Capnometry, the measurement of respiratory carbon dioxide, is regarded as a highly recommended safety technology in intubated and nonintubated sedated and/or anesthetized patients. Its utility includes confirmation of initial and ongoing placement of an airway device as well as in detecting gas exchange, bronchospasm, airway obstruction, reduced cardiac output, and metabolic changes. The utility applies prehospital and throughout all phases of inhospital care. Unfortunately, capnometry devices are not readily available in many countries, especially those that are resource-limited. Constraining factors include cost, durability of devices, availability of consumables, lack of dependable power supply, difficulty with cleaning, and maintenance. There is, thus, an urgent need for all stakeholders to come together to develop, market, and distribute appropriate devices that address costs and other requirements. To foster this process, the World Federation of Societies of Anaesthesiologists (WFSA) has developed the "WFSA-Minimum Capnometer Specifications 2021." The intent of the specifications is to set the minimum that would be acceptable from industry in their attempts to reduce costs while meeting other needs in resource-constrained regions. The document also includes very desirable and preferred options. The intent is to stimulate interest and engagement among industry, clinical providers, professional associations, and ministries of health to address this important patient safety need. The WFSA-Minimum Capnometer Specifications 2021 is based on the International Organization for Standardization (ISO) capnometer specifications. While industry is familiar with such specifications and their presentation format, most clinicians are not; therefore, this article serves to more clearly explain the requirements. In addition, the specifications as described can be used as a purchasing guide by clinicians.


Subject(s)
Anesthesiology/instrumentation , Blood Gas Monitoring, Transcutaneous/instrumentation , Carbon Dioxide/metabolism , Monitoring, Intraoperative/instrumentation , Anesthesiology/economics , Anesthesiology/standards , Blood Gas Monitoring, Transcutaneous/economics , Blood Gas Monitoring, Transcutaneous/standards , Equipment Design , Health Care Costs , Health Services Accessibility/economics , Humans , Monitoring, Intraoperative/economics , Monitoring, Intraoperative/standards , Societies, Medical
17.
Ann Vasc Surg ; 77: 274-279, 2021 Nov.
Article in English | MEDLINE | ID: mdl-34416286

ABSTRACT

PURPOSE: Photo-optical TCpO2 (pTCpO2) has been proposed as a new method to determine the partial oxygen pressure of the lower extremity in patients with peripheral arterial disease. It is aimed to determine the level of agreement between pTCpO2 and the traditional electro-chemical transcutaneous oxygen tension measurement (eTCpO2). METHODS: Eighteen patients with intermittent claudication underwent simultaneous ankle-brachial index measurement, toe-pressure, pTCpO2 and eTCpO2 tests. Oxygen tension levels were measured on anterior chest and calf prior in rest (T0), during induced ischemia (T1) and after blood flow restoration (T2). TCpO2 agreement was assessed according to the principles of Bland and Altman. RESULTS: Absolute average TCpO2 values differed between eTCpO2 and pTCpO2 for calf in T2 (38,1 mmHg (σ 14,4) vs. 49,8 (σ 22.3) with P = 0.35). The Bland-Altman plots demonstrated eTCpO2 and pTCpO2 bias of 3,7 mmHg (σ 18,8), 11,6 mmHg (σ 17,6) and 6,7 mmHg (σ 23,5) for T0, T1 and T2 for the calf. CONCLUSION: pTCpO2 is in agreement with eTCpO2 in measuring pO2 levels of the lower extremity in rest and during induced ischemia in patients with vascular claudication. The large variability between eTCpO2 and pTCpO2 should be accounted for, while pTCpO2 values have a tendency to demonstrate higher values in comparison to eTCpO2.


Subject(s)
Blood Gas Monitoring, Transcutaneous , Electrochemical Techniques , Intermittent Claudication/diagnosis , Oxygen/blood , Peripheral Arterial Disease/diagnosis , Photometry , Skin/blood supply , Aged , Biomarkers/blood , Exercise Test , Feasibility Studies , Female , Humans , Intermittent Claudication/blood , Intermittent Claudication/physiopathology , Male , Middle Aged , Peripheral Arterial Disease/blood , Peripheral Arterial Disease/physiopathology , Predictive Value of Tests
18.
Eur J Vasc Endovasc Surg ; 62(4): 583-589, 2021 10.
Article in English | MEDLINE | ID: mdl-34334314

ABSTRACT

OBJECTIVE: The aim of this study was to evaluate changes in transcutaneous oxygen pressure (tcpO2) and systolic toe pressure (TP) during endovascular intervention. METHODS: This was a single centre prospective, non-randomised, observational feasibility study. Patients with chronic limb threatening ischaemia (CLTI) due to infrainguinal disease scheduled for endovascular treatment were included between March 2018 and December 2019. TcpO2 was measured continuously bilaterally at foot level throughout the procedure and at follow up. Specific time points during the intervention were chosen for comparison to baseline (before arterial puncture): average tcpO2 level five minutes prior to percutaneous transluminal angioplasty (PTA); 10 minutes after PTA; and at completion. Bilateral TP was recorded using laser Doppler flowmetry before arterial puncture, at completion, and at clinical follow up. Angiograms were analysed for successful revascularisation and vascular lesions classified according to the Global Limb Anatomical Scoring System (GLASS). Rutherford and WIfI (Wound, Ischaemia, and foot Infection) classifications were registered, as well as clinical outcome. RESULTS: Twenty-one patients completed the study. Completion angiograms showed inline flow to the foot in all but two patients. Median time to follow up was 10 weeks (range 8 - 13 weeks) and all patients except one improved clinically. TcpO2 decreased during the initial stage of the intervention, from before arterial puncture to five minute average before PTA (p < .001) and did not recover to above baseline values at the end of intervention. TcpO2 increased significantly at follow up (p < .001). TP increased statistically significantly during intervention (p < .001) and at follow up (p < .001) compared with baseline. CONCLUSION: TcpO2 and TP measurements are safe and feasible non-invasive techniques for haemodynamic monitoring during endovascular revascularisation. TP increased significantly immediately after completion of the successful intervention, whereas tcpO2 did not. Both TP and tcpO2 demonstrated a significant increase at the 10 week follow up.


Subject(s)
Blood Gas Monitoring, Transcutaneous , Blood Pressure Determination , Blood Pressure , Endovascular Procedures , Ischemia/therapy , Oxygen/blood , Peripheral Arterial Disease/therapy , Toes/blood supply , Aged , Aged, 80 and over , Biomarkers/blood , Chronic Disease , Endovascular Procedures/adverse effects , Feasibility Studies , Female , Humans , Ischemia/diagnosis , Ischemia/physiopathology , Male , Peripheral Arterial Disease/diagnosis , Peripheral Arterial Disease/physiopathology , Predictive Value of Tests , Prospective Studies , Time Factors , Treatment Outcome
19.
J Vasc Surg ; 75(1): 255-261, 2022 01.
Article in English | MEDLINE | ID: mdl-34314832

ABSTRACT

OBJECTIVE: To compare the potential healing prognosis of the different routine noninvasive techniques implemented in the International Working Group Diabetic Foot Guidelines with the novel use of hyperspectral imaging (HSI) in patients with diabetic foot ulcers (DFUs). METHODS: Twenty-one patients with active DFUs participated in this 1-year prospective study in a specialized diabetic foot unit between December 2018 and January 2020. HSI was performed at baseline to quantify tissue oxygenation and should be presented on an anatomical map by analyzing the following parameters: (1) oxygen saturation of the hemoglobin, (2) tissue hemoglobin index, (3) the near-infrared perfusion index, and (4) tissue water index. In addition, transcutaneous oxygen pressure (TcpO2), systolic toe and ankle pressures, ankle-brachial index, and toe-brachial index values were calculated for the ulcerated limb. The primary outcome measure was wound healing, defined as complete epithelization without any drainage confirmed for at least 10 days after closure was first documented at 24 weeks. RESULTS: During the follow-up period 14 patients (66.66 %) healed and 7 patients did not heal (33.3%) by 24 weeks. The TcpO2 optimal cut-off point as determined by a balance of sensitivity and specificity of 28.5 mm Hg that yielded a sensitivity of 91% and a specificity of 100%, and area under the curve of 0.989 (P = .005; 95% confidence interval [CI], 0.945-1.000). Followed by the oxygen saturation of the hemoglobin optimal cut-off point as determined by a balance of sensitivity and specificity of 48.5 mm Hg that yielded a sensitivity of 93% and a specificity of 0.71%, and area under the curve of 0.932 (P = .013; 95% CI, 0.787-1.000). The logistic regression analyses showed that TcpO2 was the only variable associated with wound healing at 24 weeks (P < .001; 95% CI, 0.046-0.642). CONCLUSIONS: The HSI was shown to be effective in the prognosis of DFU healing compared with other noninvasive test; only TcpO2 values resulted in better diagnosis potential in wound healing.


Subject(s)
Diabetic Foot/diagnosis , Hyperspectral Imaging , Wound Healing , Aged , Aged, 80 and over , Ankle Brachial Index , Blood Gas Monitoring, Transcutaneous , Diabetic Foot/therapy , Female , Follow-Up Studies , Foot/blood supply , Humans , Male , Middle Aged , Oxygen/analysis , Prognosis , Prospective Studies , Sensitivity and Specificity , Treatment Outcome
20.
J Pediatr ; 238: 168-173.e2, 2021 Nov.
Article in English | MEDLINE | ID: mdl-34260896

ABSTRACT

OBJECTIVES: To determine, as part of our Utah Newborn Nursery Bilirubin Management Program, whether end-tidal carbon monoxide concentration (ETCOc) measurements in all newborns in our nursery receiving phototherapy were associated with outcomes related to the management of hyperbilirubinemia, including time (hours after birth) when phototherapy was initiated, total duration of phototherapy during the nursery stay, repeat phototherapy treatments, and hospital readmission for phototherapy. STUDY DESIGN: We performed a planned interim analysis of a component of our program in which we measured ETCOc noninvasively using CoSense on each newborn in our nursery receiving phototherapy and recorded specific outcomes related to phototherapy management. RESULTS: Of 1856 newborns admitted to our nursery in a 6-month period in 2020, 170 (9.8%) were treated with phototherapy. An ETCOc reading was successfully obtained in 145 of 151 attempts (96%). Higher ETCOc values were associated with earlier institution of phototherapy and longer duration of phototherapy. For every 1-ppm increase in ETCOc, phototherapy was started 9 hours earlier (95% CI, 3.3-14.8; P = .002) and was administered for an additional 9.3 hours (95% CI, 4.1-14.6; P < .001). Three newborns were readmitted to the hospital for intensive phototherapy; while in the nursery, all 3 had an elevated ETCOc (2.2, 2.6, and 2.9 ppm). CONCLUSIONS: Our findings provide answers to questions raised in the 2004 American Academy of Pediatrics bilirubin guidelines. In our neonatal nursery, measuring ETCOc in all phototherapy recipients was feasible and safe, and the results were associated with multiple aspects of phototherapy management. Higher ETCOc values predicted earlier and longer phototherapy courses.


Subject(s)
Blood Gas Monitoring, Transcutaneous/methods , Carbon Monoxide/analysis , Hyperbilirubinemia, Neonatal/blood , Phototherapy/methods , Diagnostic Tests, Routine , Feasibility Studies , Female , Humans , Infant, Newborn , Male , Quality Improvement
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