scholarly journals Carbon Dioxide Sensing—Biomedical Applications to Human Subjects

Sensors ◽  
2021 ◽  
Vol 22 (1) ◽  
pp. 188
Author(s):  
Emmanuel Dervieux ◽  
Michaël Théron ◽  
Wilfried Uhring
Keyword(s):  
Carbon Dioxide ◽  
Human Subjects ◽  
Measurement Techniques ◽  
Blood Gases ◽  
Good Alternative ◽  
Monitoring Methods ◽  
Non Invasive ◽  
Arterial Blood ◽  
Co2 Monitoring ◽  
Carbon Dioxide Co2

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.

scholarly journals P123 Accuracy and Reliability of the Transcutaneous Carbon Dioxide (TcCO2) Signal in the Sleep Laboratory

2021 ◽  
Vol 2 (Supplement_1) ◽  
pp. A61-A61
Author(s):  
A Rossely ◽  
A Turton ◽  
T Roebuck ◽  
S Ho ◽  
M Naughton ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Sleep Laboratory ◽  
Blood Gas ◽  
Sleep Study ◽  
Arterial Blood Gas ◽  
Transcutaneous Carbon Dioxide ◽  
Arterial Blood ◽  
Co2 Monitoring ◽  
Sleep Laboratories ◽  
Carbon Dioxide Co2

Abstract Carbon Dioxide (CO2) monitoring is an essential part of assessing and treating disorders of hypoventilation in the sleep laboratory. While reliablity issues have been previously reported with the Transcutaneous Carbon Dioxide (TcCO2) signal, there is limited data assessing the validity of this signal or its trend in the sleep laboratory context. Therefore, this study aimed to investigate the change in TcCO2 accuracy from the beginning to the end of the sleep study in real world conditions across two different Victorian public hospital sleep laboratories that used two different TcCO2 monitors. The sample included 13 consecutive patients from Monash Health and 44 consecutive patients from Alfred Health with an average age of 64 and 56 years respectively. Arterial Blood Gas (ABG) measurements were taken prior to and following each sleep study and compared concurrently with the TcCO2 value. Bland-Altman analysis revealed an average difference between TcCO2 and PaCO2 of 3.29mmHg with agreement between -11.44 and 16.64mmHg for the TCM4 device and 1.31mmHg with agreement between -7.64 and 9.05mmHg for the TCM5 device. When accuracy was compared across time points for each patient, 46% of patients had an overnight accuracy change of ≥ 8mmHg when using the TCM4 compared with 20% when using the TCM5. It was concluded that the TcCO2 signal was un-reliable across the different monitors and that the TcCO2 trend may be difficult to interpret with confidence without blood gas calibration at the commencement and conclusion of the sleep study.

scholarly journals A Persistently High End-Tidal Carbon Dioxide Value: Can This Be Spurious?

2019 ◽  
Vol 07 (02) ◽  
pp. 104-106
Author(s):  
Barkha Bindu ◽  
Gyaninder P. Singh ◽  
Varun Jain ◽  
Arvind Chaturvedi
Keyword(s):  
Carbon Dioxide ◽  
Unusual Case ◽  
Clinical Observation ◽  
Standard Of Care ◽  
Non Invasive ◽  
Correct Placement ◽  
Arterial Blood ◽  
End Tidal Carbon Dioxide ◽  
Carbon Dioxide Co2 ◽  
End Tidal

AbstractEnd-tidal carbon dioxide (EtCO2) monitoring has now become the standard of care not only during anesthesia but also in intensive care units for patients on mechanical ventilation, emergency department, and pre-hospital settings to confirm and monitor the correct placement of endotracheal tube. It is a non-invasive and continuous method of measuring exhaled carbon dioxide (CO2). Continuous waveform capnography measures EtCO2 and monitors ventilation. EtCO2 often correlates with partial pressure of carbon dioxide in arterial blood (PaCO2) and is a reliable indicator of PaCO2. A rise in EtCO2 often implies increased production of CO2 or decreased excretion (rebreathing, decrease ventilation) of CO2. We report an unusual case where the monitor malfunction per se lead to spuriously increased EtCO2 values without any clinical cause and did not correlate with PaCO2, thereby re-emphasizing that various monitors must always be interpreted in correlation with clinical observation.

scholarly journals Carbon Dioxide Laser Vulvovaginal Rejuvenation: A Systematic Review

Cosmetics ◽  
2021 ◽  
Vol 8 (3) ◽  
pp. 56
Author(s):  
Tassahil Messas ◽  
Achraf Messas ◽  
George Kroumpouzos
Keyword(s):  
Carbon Dioxide ◽  
Systematic Review ◽  
Laser Therapy ◽  
Carbon Dioxide Laser ◽  
Invasive Treatment ◽  
Erbium:Yag Laser ◽  
Non Invasive ◽  
Level I ◽  
Carbon Dioxide Co2

Genitourinary syndrome of menopause (GSM) causes significant symptomatic aggravation that affects the quality of life (QoL). Vulvovaginal atrophy (VVA), the hallmark of GSM, is managed with topical non-hormonal therapy, including moisturizers and lubricants, and topical estrogen application. Patients not responding/being unsatisfied with previous local estrogen therapies are candidates for a noninvasive modality. Carbon dioxide (CO2) laser therapy, especially the fractionated type (FrCO2), has drawn considerable attention over the past two decades as a non-invasive treatment for GSM. This systematic review describes the accumulated evidence from 40 FrCO2 laser studies (3466 participants) in GSM/VVA. MEDLINE, Scopus and Cochrane databases were searched through April 2021. We analyze the effects of FrCO2 laser therapy on symptoms, sexual function, and QoL of patients with GSM/VVA. As shown in this review, FrCO2 laser therapy for GSM shows good efficacy and safety. This modality has the potential to advance female sexual wellness. Patient satisfaction was high in the studies included in this systematic review. However, there is a lack of level I evidence, and more randomized sham-controlled trials are required. Furthermore, several clinical questions, such as the number of sessions required that determine cost-effectiveness, should be addressed. Also, whether FrCO2 laser therapy may exert a synergistic effect with systemic and/or local hormonal/non-hormonal treatments, energy-based devices, and other modalities to treat GMS requires further investigation. Lastly, studies are required to compare FrCO2 laser therapy with other energy-based devices such as erbium:YAG laser and radiofrequency.

scholarly journals Pathophysiology and clinical consequences of arterial blood gases and pH after cardiac arrest

2020 ◽  
Vol 8 (S1) ◽  
Author(s):  
Chiara Robba ◽  
Dorota Siwicka-Gieroba ◽  
Andras Sikter ◽  
Denise Battaglini ◽  
Wojciech Dąbrowski ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Mechanical Ventilation ◽  
Cardiac Arrest ◽  
Oxygen Demand ◽  
Blood Gases ◽  
Metabolic Energy ◽  
High Morbidity ◽  
Arterial Blood Gases ◽  
Arterial Blood ◽  
Clinical Consequences

AbstractPost cardiac arrest syndrome is associated with high morbidity and mortality, which is related not only to a poor neurological outcome but also to respiratory and cardiovascular dysfunctions. The control of gas exchange, and in particular oxygenation and carbon dioxide levels, is fundamental in mechanically ventilated patients after resuscitation, as arterial blood gases derangement might have important effects on the cerebral blood flow and systemic physiology.In particular, the pathophysiological role of carbon dioxide (CO2) levels is strongly underestimated, as its alterations quickly affect also the changes of intracellular pH, and consequently influence metabolic energy and oxygen demand. Hypo/hypercapnia, as well as mechanical ventilation during and after resuscitation, can affect CO2 levels and trigger a dangerous pathophysiological vicious circle related to the relationship between pH, cellular demand, and catecholamine levels. The developing hypocapnia can nullify the beneficial effects of the hypothermia. The aim of this review was to describe the pathophysiology and clinical consequences of arterial blood gases and pH after cardiac arrest.According to our findings, the optimal ventilator strategies in post cardiac arrest patients are not fully understood, and oxygen and carbon dioxide targets should take in consideration a complex pattern of pathophysiological factors. Further studies are warranted to define the optimal settings of mechanical ventilation in patients after cardiac arrest.

Stimulation of ventilation in emphysema by passively induced body motion

1962 ◽  
Vol 17 (5) ◽  
pp. 771-774 ◽  
Author(s):  
Herman F. Froeb
Keyword(s):  
Carbon Dioxide ◽  
Technical Assistance ◽  
Ventilatory Response ◽  
Minute Ventilation ◽  
Blood Gases ◽  
Body Motion ◽  
Therapeutic Tool ◽  
Arterial Blood ◽  
Weak Muscle ◽  
Normal Males

The ventilatory stimulation arising from two different forms of passively induced body motion was chosen for study of 14 male emphysematous subjects with hypercapnia and impaired ventilatory response to carbon dioxide. Nine normal males served as controls. The object of the study was to determine whether the stimulus to ventilation from passive body motion was intact in diseased subjects and whether it could serve as a therapeutic tool by bringing about a reduction in blood carbon dioxide. The results revealed that the stimulus to ventilation was mild and comparable in both groups but was associated with two to three times more oxygen per extra liter of minute ventilation in the diseased subjects. There were no significant changes in the arterial blood gases. It was concluded that the stimulus to ventilation from passive body motion arises from weak muscle action and has no therapeutic application in emphysematous subjects as a means of lowering the PaCOCO2. Note: (With the Technical Assistance of Mabel Pearson, Roy Engstrom, Christa McReynolds, and Carol Kennedy) Submitted on March 5, 1962

scholarly journals Assessment of recent advances in measurement techniques for atmospheric carbon dioxide and methane observations

2016 ◽  
Vol 9 (9) ◽  
pp. 4737-4757 ◽  
Author(s):  
Christoph Zellweger ◽  
Lukas Emmenegger ◽  
Mohd Firdaus ◽  
Juha Hatakka ◽  
Martin Heimann ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Atmospheric Carbon Dioxide ◽  
Measurement Techniques ◽  
Spectroscopic Techniques ◽  
Cavity Output ◽  
The World ◽  
Atmospheric Carbon ◽  
Carbon Dioxide Co2 ◽  
Improved Accuracy ◽  
Flame Ionisation

Abstract. Until recently, atmospheric carbon dioxide (CO2) and methane (CH4) measurements were made almost exclusively using nondispersive infrared (NDIR) absorption and gas chromatography with flame ionisation detection (GC/FID) techniques, respectively. Recently, commercially available instruments based on spectroscopic techniques such as cavity ring-down spectroscopy (CRDS), off-axis integrated cavity output spectroscopy (OA-ICOS) and Fourier transform infrared (FTIR) spectroscopy have become more widely available and affordable. This resulted in a widespread use of these techniques at many measurement stations. This paper is focused on the comparison between a CRDS "travelling instrument" that has been used during performance audits within the Global Atmosphere Watch (GAW) programme of the World Meteorological Organization (WMO) with instruments incorporating other, more traditional techniques for measuring CO2 and CH4 (NDIR and GC/FID). We demonstrate that CRDS instruments and likely other spectroscopic techniques are suitable for WMO/GAW stations and allow a smooth continuation of historic CO2 and CH4 time series. Moreover, the analysis of the audit results indicates that the spectroscopic techniques have a number of advantages over the traditional methods which will lead to the improved accuracy of atmospheric CO2 and CH4 measurements.

Acute anoxia

1954 ◽  
Vol 143 (910) ◽  
pp. 5-8
Keyword(s):  
Human Subjects ◽  
Blood Gases ◽  
Ventilation Rate ◽  
Dynamic State ◽  
Arterial Blood ◽  
Acute Anoxia ◽  
Adequate Stimulus ◽  
Young Subjects ◽  
Alveolar Oxygen ◽  
Oxyhaemoglobin Saturation

A general physiological interest in anoxia has resulted in such a vast literature that, in this short communication, only data of importance to aviation are included, from observations on human subjects. In the case of flying personnel, acute anoxia should be regarded as a dynamic state, due to a fall in the partial pressure of alveolar oxygen to a level at which new conditions of equilibrium of blood gases are unlikely to he achieved, without marked systemic or mental changes. In normal fit young subjects at rest, it is possible to achieve equilibrium in oxyhaemoglobin saturation of the arterial blood, with exposures of 5 to 10 min. at altitudes up to 18000 ft., and up to 22000 ft. in a large proportion of such subjects. Under such conditions, the oxyhaemoglobin saturation does not fall below 90% until 10000 ft. has been reached, the resulting fall in efficiency of members of aircrew being slight, and only apparent after exposure of hours, except for a reduction of visual capacity at night. The sensitivity of the chemo-receptors to alterations in oxygen tension of the blood undoubtedly varies from individual to individual, but a fall of 50 mm Hg can be regarded as an adequate stimulus for a definite increase in pulse rate and ventilation rate.

Aortic body chemoreceptor responses to changes in PCO2 and PO2 in the cat

1979 ◽  
Vol 47 (4) ◽  
pp. 858-866 ◽  
Author(s):  
S. Lahiri ◽  
E. Mulligan ◽  
T. Nishino ◽  
A. Mokashi
Keyword(s):  
Carbon Dioxide ◽  
Discharge Rate ◽  
Arterial Oxygen Tension ◽  
Blood Gases ◽  
Carbon Dioxide Tension ◽  
Steady States ◽  
Arterial Oxygen ◽  
Arterial Blood ◽  
Discharge Rates ◽  
End Tidal

Responses of aortic chemoreceptor afferents to a range of arterial carbon dioxide tension (Paco2) changes at various levels of arterial oxygen tension (Pao2) were investigated in 18 cats anesthetized with alpha-chloralose and maintained at 38 degrees C. Aortic chemoreceptor activity, end-tidal oxygen pressure, end-tidal carbon dioxide pressure, and arterial blood pressure were continuously monitored. Arterial blood gases were measured in steady states. Single or a few clearly identifiable afferents were studied during changes and steady states of Pao2 and Paco2. All the aortic chemoreceptor afferent discharge rates increased with Paco2 increases from hypercapnia (10–15 Torr) to normocapnia and moderate hypercapnia (30–50 Torr) and with Pao2 decreases from above 400 to 30 Torr. Hypoxia augmented the response to Paco2 most effectively in the range of 10–40 Torr. At any Pao2, the discharge rate reached a plateau with sufficient intensity of hypercapnia. The Paco2 stimulus threshold at a Pao2 of 440 Torr was about 15 Torr, and at a Pao2 of 60 Torr it was 10 Torr. In the transition from hypocapnia to hypercapnia, responses increased gradually, usually without an overshoot. The steady-state responses to Paco2 of the majority of aortic chemoreceptors resembled those of carotid chemoreceptors. The responses of both receptors can be attributed to the same basic type of mechanism.

Adjustments in oxygen transport during head-out immersion in water at different temperatures

1990 ◽  
Vol 68 (4) ◽  
pp. 1475-1480 ◽  
Author(s):  
M. L. Choukroun ◽  
P. Varene
Keyword(s):  
Human Subjects ◽  
Blood Gases ◽  
Arterial Blood Gases ◽  
Quiet Breathing ◽  
Pulmonary Tissue ◽  
Arterial Blood ◽  
O2 Transport ◽  
Neutral Temperature ◽  
Different Temperatures ◽  
Circuit Technique

Respiratory gas exchange was investigated in human subjects immersed up to the shoulders in water at different temperatures (Tw = 25, 34, and 40 degrees C). Cardiac output (Qc) and pulmonary tissue volume (Vti) were measured by a rebreathing technique with the inert gas Freon 22, and O2 consumption (VO2) was determined by the closed-circuit technique. Arterial blood gases (PaO2, PaCO2) were analyzed by a micromethod, and alveolar gas (PAO2) was analyzed during quiet breathing with a mass spectrometer. The findings were as follows. 1) Immersion in a cold bath had no significant effect on Qc compared with the value measured at Tw = 34 degrees C, whereas immersion in a hot bath led to a considerable increase in Qc. Vti was not affected by immersion at any of the temperatures tested. 2) A large rise in metabolic rate VO2 was only observed at Tw = 25 degrees C (P less than 0.001). 3) Arterial blood gases were not significantly affected by immersion, whatever the water temperature. 4) O2 transport during immersion is affected by two main factors: hydrostatic pressure and temperature. Above neutral temperature, O2 transport is improved because of the marked increase in Qc resulting from the combined actions of hydrostatic counter pressure and body heating. Below neutral temperature, O2 transport is altered; an increase in O2 extraction of the tissue is even calculated.

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