Transcutaneous Oxygen Monitors Are Reliable Indicators of Arterial Oxygen Tension (If Used Correctly)

PEDIATRICS ◽  
1987 ◽  
Vol 79 (2) ◽  
pp. 283-286 ◽  
Author(s):  
G. ROOTH ◽  
A. HUCH ◽  
R. HUCH
Keyword(s):  
Premature Infants ◽  
Arterial Oxygen Tension ◽  
Arterial Oxygen ◽  
Term Infants ◽  
Transcutaneous Oxygen ◽  
Basic Understanding ◽  
Arterial Po2 ◽  
Transcutaneous Po2

The following recommendations should always be kept in mind: 1. Each new transcutaneous equipment, or modification of equipment, must be adequately tested in vivo as well as in vitro. 2. The users must have basic understanding of the principles and the major requirements for applying the tcPo2 technique. 3. Calibration procedures must be carefully adhered to according to the manufacturer's instruction. 4. The temperature of the electrode must be kept at 44°C for premature infants and at 44° or 45°C for term infants if the clinical aim is to estimate arterial Po2 levels. Resetting of the electrode must then be done every two hours. For sick infants, this may be needed more frequently. 5. Whenever there is cause to compare tcPo2 values with arterial ones, the latter must be obtained from an appropriate vessel. Great care must be taken when drawing and analyzing blood for Po2. The infant should not be crying. 6. Significantly lower transcutaneous Po2 values than arterial Po2 values are due to either one or several of the errors indicated above or to an insufficient circulation under the electrode. In recent years, technical or clinical errors seem to have become more and more common. Thereby the technique has unjustly fallen into disrepute. 7. Insufficient circulation under the electrode rarely occurs in the newborn infant and then only in those who are in overt shock.

Direct pulmonary vascular responses in the conscious newborn lamb

1980 ◽  
Vol 48 (1) ◽  
pp. 188-196 ◽  
Author(s):  
J. E. Lock ◽  
F. Hamilton ◽  
H. Luide ◽  
F. Coceani ◽  
P. M. Olley
Keyword(s):  
Pulmonary Artery ◽  
Pulmonary Arteries ◽  
Arterial Oxygen Tension ◽  
Arterial Oxygen ◽  
Vascular Effects ◽  
Flow Probe ◽  
Pulmonary Artery Flow ◽  
Artery Flow

Electromagnetic flow probes were placed around the right and left pulmonary arteries (RPA and LPA) of nine newborn lambs. Preliminary in vitro and in vivo experiments delineated the accuracy and limitations of this method of flow measurement and the value in vivo of a balloon occlusive zero. Six to nine days after surgery, catheters were placed in the aorta and a branch pulmonary artery permitting simultaneous measurements of RPA and LPA flow, pulmonary arterial pressure, and aortic pressure. Vasoactive agents were injected into one lung, and a shift in blood flow distribution reflected direct active vasoconstruction or vasodilation in that lung. With a normal arterial oxygen tension, acetylcholine had no direct effect on the pulmonary vessels, but indirectly lowered pulmonary resistance via its systemic effects. Histamine was a potent direct pulmonary vasoconstrictor, bradykinin was a weak direct dilator, norepinephrine was a direct constrictor, prostaglandin E1 was a direct dilator, and prostaglandin F2a was a direct constrictor. These results demonstrate the feasibility of isolating the direct pulmonary vascular effects of certain pharmacologic agents using a double pulmonary artery flow probe preparation, agents using a double pulmonary artery flow probe preparation, without the use of anesthetics or extracorporeal perfusion circuits.

Comparison of Transcutaneous Oxygen Tension With Arterial Oxygen Tension in Newborn Infants With Severe Respiratory Illnesses

PEDIATRICS ◽  
1978 ◽  
Vol 62 (5) ◽  
pp. 692-697 ◽  
Author(s):  
Peter N. le Souëf ◽  
Andrew K. Morgan ◽  
Linda P. Soutter ◽  
E. Osmund R. Reynolds ◽  
Dawood Parker
Keyword(s):  
Oxygen Tension ◽  
Newborn Infants ◽  
Arterial Oxygen Tension ◽  
Oxygen Electrode ◽  
Electrode Site ◽  
Arterial Oxygen ◽  
Transcutaneous Oxygen ◽  
Skin Changes ◽  
Respiratory Illnesses

Transcutaneous oxygen tesion (tcPO2), measured by two skin electrodes of different design, and arterial oxygen tension (PaO2), measured by an intravascular oxygen electrode, were continuously recorded for periods of six hours in 15 newborn infants with serious respiratory illnesses. Ten of the infants needed mechanical ventilation and three needed continuous positive airway pressure. One skin electrode had three microcathodes surrounded by a heated ring-shaped anode, and the other had a large heated cathode. The temperature of both electrodes was set at 44°C and they were calibrated in vitro. The tcPO2 recorded by the electrode with the microcathodes was found to estimate PaO2 reasonably accurately for the whole six-hour duration of the study. The tcPO2 recorded by the electrode with the large cathode gave a similar estimate of PaO2. for three hours, but then tcPO2. often fell relative to PaO2. This fall was probably caused by skin changes at the electrode site. For a variety of reasons, our results suggest that measurement of tcPO2. is unlikely to replace continuous intravascular measurement of PaO2. in infants with severe respiratory illnesses.

Effect of Electrode Temperature and in Vivo Calibration on Accuracy of Transcutaneous Estimation of Arterial Oxygen Tension in Infants

PEDIATRICS ◽  
1980 ◽  
Vol 65 (3) ◽  
pp. 515-522
Author(s):  
Melanie J. Pollitzer ◽  
Michelle D. Whitehead ◽  
E. Osmund R. Reynolds ◽  
David Delpy
Keyword(s):  
Oxygen Tension ◽  
Newborn Infants ◽  
Arterial Oxygen Tension ◽  
Oxygen Electrode ◽  
Arterial Oxygen ◽  
Optimal Temperature ◽  
Transcutaneous Oxygen ◽  
Skin Electrodes ◽  
In Vivo Calibration

Previous studies showed that a skin oxygen electrode with a macrocathode, when heated to 43 C, underestimated arterial oxygen tension (Pao2). At 44 C the skin was damaged. The purpose of the present study was to assess the accuracy of the macrocathode electrode when set at 43.5 C. Transcutaneous oxygen tension (tcPo2) recorded by the macrocathode electrode at 43.5 C was compared with Pao2 measured continuously with an intravascular oxygen electrode, and with tcPo2 recorded by a microcathode electrode which has been shown earlier to work well at a temperature of 44 C. Both the skin electrodes were calibrated in vitro and in vivo. Particular attention was given to the details of calibration. Twelve newborn infants with respiratory illnesses were studied, each for six hours. Transcutaneous Po2 recorded by both skin electrodes was found to estimate Pao2 resonably accurately for the entire six-hour duration of the study, with the exception of a large and unexplained overestimation of Pao2 by the macrocathode electrode in one infant. This overestimation was corrected by in vivo calibration. Serious skin lesions were not seen after the skin electrodes were removed. We conclude that (1) The temperature setting of skin electrodes is crucial to their satisfactory performance. (2) For use on newborn infants, 43.5 C is the optimal temperature for the macrocathode electrode. (3) The optimal temperature for the microcathode electrode was confirmed as 44 C. (4) At these temperatures, both electrodes could be left on the same site on the skin for six hours. (5) Periodic in vivo calibration of skin electrodes is advisable.

Transcutaneous Determination of Arterial Oxygen Tension

PEDIATRICS ◽  
1975 ◽  
Vol 55 (2) ◽  
pp. 224-231
Author(s):  
A. Fenner ◽  
R. Müller ◽  
H. G. Busse ◽  
M. Junge ◽  
J. Wolfsdorf
Keyword(s):  
Oxygen Tension ◽  
Newborn Infants ◽  
Arterial Oxygen Tension ◽  
Correlation Coefficients ◽  
Arterial Oxygen ◽  
Transcutaneous Oxygen Tension ◽  
Term Infants ◽  
Transcutaneous Oxygen ◽  
Developed Surface ◽  
Cutaneous Perfusion

Arterial oxygen tension measurements were performed simultaneously using two different techniques: (1) the conventional method of analyzing a blood sample obtained from the radial artery by means of a Clark electrode and (2) a new method of transcutaneous oxygen tension recording using a newly developed surface electrode containing a built-in heating device to ensure optimal cutaneous perfusion at the site of measurement. Two groups of newborn infants were used as subjects: (1) 70 clinically healthy babies who were tested during normoxia and hyperoxia (breathing 80% to 100% oxygen) and (2) 20 sick preterm and term infants receiving inspired oxygen concentrations of between 21% and 100% during the measurement. Our results indicate a satisfactory accuracy for the transcutaneous oxygen tension measurements in normoxia and hyperoxia (percentage coefficient of variation, 15.9% and 24.1%, respectively). In hypoxia agreement between the two methods varies depending on the degree of circulatory derangement. Overall correlation coefficients were greater than 0.85 in each group.

scholarly journals Successful Transtracheal Lung Ventilation Using a Manual Respiration Valve

2008 ◽  
Vol 109 (2) ◽  
pp. 251-259 ◽  
Author(s):  
Konrad Meissner ◽  
Thomas Iber ◽  
Jan-Patrick Roesner ◽  
Christian Mutz ◽  
Hans-Erich Wagner ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Arterial Oxygen Tension ◽  
Upper Airway ◽  
Lung Ventilation ◽  
Carbon Dioxide Tension ◽  
Arterial Oxygen ◽  
Gas Flows ◽  
Partial Pressures

Background Lung ventilation through a thin transtracheal cannula may be attempted in patients with laryngeal stenosis or "cannot intubate, cannot ventilate" situations. It may be impossible to achieve sufficient ventilation if the lungs are spontaneously emptying only through the thin transtracheal cannula, which imposes high resistance to airflow, resulting in dangerous hyperinflation. Therefore, the authors describe the use of a manual respiration valve that serves as a bidirectional pump providing not only inflation but also active deflation of the lungs in case of emergency transtracheal lung ventilation. Methods The effectiveness of such a valve was tested in vitro using mechanical lungs in combination with two different cannula sizes and various gas flows. The valve was then tested in five pigs using a transtracheal 16-gauge cannula with three different combinations of inspiratory/expiratory times and gas flows and an occluded upper airway. Results In the mechanical lungs, the valve permitted higher minute volumes compared with spontaneous lung emptying. In vivo, the arterial oxygen and carbon dioxide partial pressures increased initially and then remained stable over 1 h (arterial oxygen tension, 470.8 +/- 86.8; arterial carbon dioxide tension, 63.0 +/- 7.2 mmHg). The inspiratory pressures measured in the trachea remained below 10 cm H2O and did not substantially influence central venous and pulmonary artery pressures. Mean arterial pressure and cardiac output were unaffected by the ventilation maneuvers. Conclusions This study demonstrated in vitro and in vivo in adult pigs that satisfactory lung ventilation can be assured with transtracheal ventilation through a 16-gauge cannula for a prolonged period of time if combined with a bidirectional manual respiration valve.

THORACIC GAS VOLUME CHANGES IN PREMATURE INFANTS

PEDIATRICS ◽  
1967 ◽  
Vol 40 (3) ◽  
pp. 403-411
Author(s):  
D. W. Thibeault ◽  
M. M. Wong ◽  
P. A. M. Auld
Keyword(s):  
Oxygen Tension ◽  
Premature Infants ◽  
Arterial Oxygen Tension ◽  
Full Term ◽  
Arterial Oxygen ◽  
Volume Changes ◽  
Term Infants ◽  
Thoracic Gas Volume ◽  
Gas Volume ◽  
Serial Measurements

Serial measurements of thoracic gas volume and arterial oxygen tension in a group of small premature infants are reported. The study demonstrated that when thoracic gas volume reached levels for normal, full-term infants arterial oxygen tension approached full-term values. The study indicates extensive pulmonary abnormality in clinically non-distressed premature infants, most likely due to persistent atelectasis or partially aerated alveoli. Observations suggest that the infant attempts to correct this abnormality by frequent periodic hyperinflations or sighs.

Limitations of Transcutaneous Po2 and Pco2 Monitoring in Infants with Bronchopulmonary Dysplasia

PEDIATRICS ◽  
1984 ◽  
Vol 74 (2) ◽  
pp. 217-220
Author(s):  
Ellen S. Rome ◽  
Eileen K. Stork ◽  
Waldemar A. Carlo ◽  
Richard J. Martin
Keyword(s):  
Bronchopulmonary Dysplasia ◽  
Premature Infants ◽  
Neonatal Period ◽  
Postnatal Life ◽  
Pco2 Monitoring ◽  
Arterial Po2 ◽  
Transcutaneous Po2

Despite the well-documented correlation between transcutaneous and arterial Po2 and Pco2 in sick neonates, the effect of maturation on this relationship has not been well characterized. Eight premature infants with bronchopulmonary dysplasia (BPD) and indwelling arterial lines beyond the immediate neonatal period were studied. Transcutaneous Po2 always underestimated Pao2 beyond 10 weeks of postnatal life, such that transcutaneous Po2 - Pao2 was -16 ± 5 torr (P < .001). Corrected transcutaneous Pco2 simultaneously overestimated PaCo2 by 9 ± 3 torr (P < .001), although this occurred over a wider range of postnatal ages. Transcutaneous Po2 monitoring may be a useful tool for estimating Pao2 in this population, provided an appropriate correction is made beyond 10 weeks of age. It is suggested that caution be exercised when using transcutaneous Pco2 measurements to estimate absolute arterial values in older infants with bronchopulmonary dysplasia.

Effect of Acute Hemorrhage on Transcutaneous, Subcutaneous, Intramuscular, and Arterial Oxygen Tensions

PEDIATRICS ◽  
1980 ◽  
Vol 65 (5) ◽  
pp. 881-883
Author(s):  
Frederick A. Matsen ◽  
Craig R. Wyss ◽  
Racheal V. King ◽  
Charles W. Simmons
Keyword(s):  
Arterial Oxygen ◽  
Peripheral Blood Flow ◽  
Danger Signal ◽  
Close Approximation ◽  
Monitoring Method ◽  
Acute Hemorrhage ◽  
Tissue Po2 ◽  
Oxygen Tensions ◽  
Arterial Po2 ◽  
Transcutaneous Po2

Although transcutaneous Po2 is a close approximation of arterial Po2 in most neonates, infants in shock often show lower transcutaneous than arterial Po2 values. For a better understanding of this discrepancy, we investigated the effect of acute hemorrhage on transcutaneous, tissue, and arterial Po2 in rabbits. With progressive hemorrhage, transcutaneous and tissue Po2 values declined steeply while arterial Po2 values did not. We speculate that the progressive decrement in transcutaneous and tissue Po2 values with hemorrhage is produced by diminished peripheral blood flow. Rather than representing a failure of the transcutaneous Po2 monitoring method, we speculate that transcutaneous hypoxia with shock may be a clinically valuable danger signal.

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