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Reprinted from the September 2004 issue of RESPIRATORY CARE [Respir Care 2004; 49(9):1070–1072]

AARC Clinical Practice Guideline

Transcutaneous Blood Gas Monitoring for Neonatal & Pediatric
Patients—2004 Revision & Update

Transcutaneous monitoring of oxygen (PtcO2) and carbon dioxide (PtcCO2) in neonates, infants, and small children—this guideline does not address the application of transcutaneous monitoring in adults and older children.

Transcutaneous monitoring measures skin-surface PO2 and PCO2 to provide estimates of arterial partial pressure of oxygen and carbon dioxide (PaO2 and PaCO2). The devices induce hyperperfusion by local heating of the skin and measure the partial pressure of oxygen and carbon dioxide electrochemically.1-8

Transcutaneous monitoring may be performed by trained personnel in a variety of settings including (but not limited to) hospitals, extended care facilities, and patient transport.9,10


4.1 The need to monitor the adequacy of arterial oxygenation and/or ventilation11-13
4.2 The need to quantitate the response to diagnostic and therapeutic interventions as evidenced by PtcO2 and/or PtcCO2 values11,12,14,15

In patients with poor skin integrity and/or adhesive allergy, transcutaneous monitoring may be relatively contraindicated.11

PtcO2 and/or PtcCO2 monitoring is considered a safe procedure, but because of device limitations, falsenegative and false-positive results may lead to inappropriate treatment of the patient.12,16-18 In addition, tissue injury may occur at the measuring site (eg, erythema, blisters, burns, skin tears).1,9,12,19

PtCO2 is an indirect measurement of PaO2 and, like PaO2, does not reflect oxygen delivery or oxygen content. Complete assessment of oxygen delivery requires knowledge of hemoglobin, saturation, and cardiac output. In a similar way, PtcCO2 is an indirect measurement of PaCO2 but knowledge of delivery and content is not necessary to use PtcCO2 as an indicator of adequacy of ventilation.

7.1 Factors, agents, or situations that may affect readings, limit precision, or limit the performance or application of a transcutaneous monitor

7.1.1 Technical The procedure may be labor intensive, although newer designs make application quicker and simpler.20 Prolonged stabilization time is required following electrode placement. 20,21 Manufacturers state that electrodes
must be heated to produce valid results; however, clinical studies suggest that valid results may be obtained with PtcCO2 electrodes operated at lower than recommended temperatures or with no heat.19,22 The theoretical basis for mandatory heating of the PtcO2 electrode is established.2,23 Improper calibration, trapped air bubbles, damaged membranes are possible and may be difficult to detect.14,24,25

7.1.2 Clinical: The following factors may increase the discrepancy between arterial and transcutaneous values The presence of hyperoxemia (PaO2 > 100 torr)22,23,25 The presence of a hypoperfused state (shock, acidosis)9,18,26,27 Improper electrode placement or application9 Vasoactive drugs9,18 The nature of the patient’s skin and subcutaneous tissue (skinfold thickness, edema)9,18,28

7.2 Validation: Arterial blood gas values should be compared to transcutaneous readings taken at the time of arterial sampling in order to validate the transcutaneous values. This validation should be performed initially and periodically as dictated by the patient’s clinical state.9,25,29

7.2.1 During validation studies in patients with functional shunts, electrode site and arterial sampling site should be on the same side of the shunt.12,30
7.2.2 When disparity exists between transcutaneous and arterial values and the clinical presentation of the patient, possible causes should be explored before results are reported. Monitoring at alternate sites, recalibration, or appropriate substitution of instruments may reduce discrepancies. If such steps do not remedy the disparity, transcutaneous results should not be reported; instead a statement describing the corrective action should be included in the patient’s chart and some other mode of monitoring should be established (eg, pulse oximetry and/or arterial blood analysis). The absolute limits that constitute unacceptable disparity vary with patient condition and specific device. Clinical judgment must be exercised.

7.3 To help assure consistency of care based on transcutaneous blood gas readings, the operator should verify that

7.3.1 High- and low-limit alarms are set appropriately
7.3.2 Appropriate electrode temperature is set
7.3.3 Electrode placement is appropriate and systematic electrode-site change occurs
7.3.4 Specific manufacturer’s recommendations for maintenance, operation, and safety are complied with


8.1 When direct measurement of arterial blood is not available or accessible in a timely fashion, PtcO2 and/or PtcCO2 measurements may temporarily suffice if the limitations of the data are appreciated.11
8.2 Transcutaneous blood gas monitoring is appropriate for continuous and prolonged monitoring (eg, during mechanical ventilation, CPAP, and supplemental oxygen administration).11,12,24
8.3 PtcO2 values can be used for diagnostic purposes as in the assessment of functional shunts (eg, persistent pulmonary hypertension of the newborn, PPHN, or persistent fetal circulation or to determine the response to oxygen challenge in the assessment of congenital heart disease.30-33


9.1 Results should reflect the patient’s clinical condition (ie, validate the basis for ordering the monitoring).3,5,7,13,29
9.2 Documentation of results, therapeutic intervention (or lack of), and/or clinical decisions based on the transcutaneous measurements should be noted in the medical record.


10.1 Equipment: Transcutaneous monitor, electrodes, calibration gases, and associated expendable supplies—the monitor should have been validated by the manufacturer, using appropriate quality control procedures and clinical reliability studies
10.2 Personnel: Licensed or credentialed respiratory care practitioners or other credentialed persons with equivalent training and demonstrated ability to exercise the necessary clinical judgment, assess the patient, and perform the essential tasks of calibration and application9,18

The monitoring schedule of patient and equipment during transcutaneous monitoring should be integrated into patient assessment and vital signs determinations. Results should be documented in the patient’s medical record and should detail the conditions under which the readings were obtained.

11.1 The date and time of measurement, transcutaneous reading, patient’s position, respiratory rate, and activity level
11.2 Inspired oxygen concentration or supplemental oxygen flow, specifying the type of oxygen delivery device
11.3 Mode of ventilatory support, ventilator, or CPAP settings
11.4 Electrode placement site, electrode temperature, and time of placement
11.5 Results of simultaneously obtained PaO2, PaCO2, and pH when available
11.6 Clinical appearance of patient, subjective assessment of perfusion, pallor, and skin temperature

Transcutaneous blood gas monitoring should be continuous for development of trending data. Socalled spot checks are not appropriate.3,11,12,34

No special precautions are necessary, but Standard Precautions (as described by the Centers for Disease Control) are recommended.35-38

13.1 The device probe should be cleaned between patient applications according to manufacturer recommendations.
13.2 The external portion of the monitor should be cleaned according to manufacturer’s recommendations whenever the device remains in a patient’s room for prolonged periods, when soiled, or when it has come in contact with potentially transmissible organisms.


Revised by Steven E Sittig RRT-NPS, Mayo Clinic, Rochester, Minnesota, and approved by the 2003 CPG Steering Committee

Original Publication: Respir Care 1994:39(12):1176-1179.



  1. Löfgren O, Jacobson J. The influence of different electrode temperatures on the recorded transcutaneous PO2 level. Pediatrics 1979;64(6):892-897.
  2. Lübbers DW. Theoretical basis of the transcutaneous blood gas measurements. Crit Care Med 1981;9(10):721-733.
  3. Huch R, Huch A, Albani M, Gabriel M, Schulte FJ, Wolf H, et al. Transcutaneous PO2 monitoring in routine management of infants and children with cardiorespiratory problems. Pediatric 1976;57(5):681-690.
  4. Monaco F, Nickerson BG, McQuitty JC. Continuous transcutaneous oxygen and carbon dioxide monitoring in the pediatric ICU. Crit Care Med 1982;10(11):765- 766.
  5. Yahav J, Mindorff C, Levison H. The validity of the transcutaneous oxygen tension method in children with cardiorespiratory problems. Am Rev Respir Dis 1981;124(5):586-587.
  6. Yip WC, Tay JS, Wong HB, Ho TF. Reliability of transcutaneous oxygen monitoring of critically ill children in a general pediatric unit. Clin Pediatr Phila 1983;22(6):431-435.
  7. Fenner A, Muller R, Busse HG, Junge M, Wolfsdorf J. Transcutaneous determination of arterial oxygen tension. Pediatrics 1975;55(2):224-231.
  8. Mike V, Krauss AN, Ross GS. Doctors and the health industry: a case study of transcutaneous oxygen monitoring in the neonatal intensive care. Soc Sci Med 1996;42(9):1247-1258.
  9. American Academy of Pediatrics, Task Force on Transcutaneous Oxygen Monitors. Report of consensus meeting, Dec 5-6, 1986. Pediatrics 1989;83(1):122-126.
  10. O’Connor TA, Grueber R. Transcutaneous measurement of carbon dioxide tension during long-distance transport of neonates receiving mechanical ventilation. J Perionatal 1998;18(3):189-192.
  11. Martin. RJ. Transcutaneous monitoring: instrumentation and clinical applications. Respir Care 1990;35(6):577- 583.
  12. Lucey JF. Clinical uses of transcutaneous oxygen monitoring. Adv Pediatr 1981;28:27-56.
  13. Berkenbosch JW, Tobias JD. Transcutaneous carbon dioxide monitoring during high-frequency oscillatory ventilation in infants and children. Crit Care Med 2002;30(5):1024-1027.
  14. Severinghaus JW. Transcutaneous blood gas analysis. Respir Care 1982;27(2):152-159.
  15. Saga R, Mochizuki H, Tokuyama K, Morikawa A. Relationship between bronchial hyperresponsiveness and development of asthma in wheezy infants. Chest 2001;119(3):685-690.
  16. Huch R, Lübbers W, Huch A. Reliability of transcutaneous monitoring of arterial PO2 in newborn infants. Arch Dis Child 1974;49(3):213-218.
  17. Martin RJ, Robertson SS, Hopple MM. Relationship between transcutaneous and arterial oxygen tension in sick neonates during mild hyperoxemia. Crit Care Med 1982;10(10):670-672.
  18. Tobias JD, Wilson MR Jr, Meyer DJ. Transcutaneous monitoring of carbon dioxide tension after cardiothoracic surgery in infants and children. Anesth Analg 1999;88(3):531-534.
  19. Fanconi S, Tschupp A, Molinari L. Long-term transcutaneous monitoring of oxygen tension and carbon dioxide at 42 degrees C in critically ill neonates: improved performance of the tcPO2 monitor with topical metabolic inhibition. Eur J Pediatr 1996;155(12):1043-1046.
  20. Kesten S, Chapman KR, Rebuck AS. Response characteristics of a dual transcutaneous oxygen/carbon dioxide monitoring system. Chest 1991;99(5):1211-1215.
  21. Marsden D, Chiu MC, Paky F, Helms P. Transcutaneous oxygen and carbon dioxide monitoring in intensive care. Arch Dis Child 1985;60(12):1158-1161.
  22. McLellan PA, Goldstein RS, Ramcharan V, Rebuck AS. Transcutaneous carbon dioxide monitoring. Am Rev Respir Dis 1981;124(2):199-201.
  23. Wahr JA, Tremper KK. Noninvasive oxygen monitoring techniques. Crit Care Clin 1995;11(1):199-217.
  24. Tobias JD, Meyer DJ. Noninvasive monitoring of carbon dioxide during respiratory failure in toddlers and infants: end-tidal versus transcutaneous carbon dioxide. Anesth Analg 1997;85(1):55-58.
  25. Cassady G. Transcutaneous monitoring in the newborn infant. J Pediatr 1983;103(6):837-848.
  26. Versmold HT, Linderkamp O, Holzmann M, Stohhacker I, Riegel K. Transcutaneous monitoring of PO2 in newborn infants: where are the limits? Influence of blood pressure, blood volume, blood flow, viscosity, and acid base state. Birth Defects 1979;15(4):285-294.
  27. Peabody JL, Gregory GA, Willis MM, Tooley WH. Transcutaneous oxygen tension in sick infants. Am Rev Respir Dis 1978;118(1):83-87.
  28. Mok J, Pintar M, Benson L, McLaughlin FJ, Levison H. Evaluation of noninvasive measurements of oxygenation in stable infants. Crit Care Med 1986;14(11):960-963.
  29. Brouillette RT, Waxman DH. Evaluation of the newborn’s blood gas status. National Academy of Clinical Biochemistry. Clin Chem 1997;43(1):215-221.
  30. Pearlman SA, Maisels MJ. Preductal and postductal transcutaneous oxygen tension measurements in premature newborns with hyaline membrane disease. Pediatrics 1989;83(1):98-100.
  31. Tateishi K, Yamanouchi I. Noninvasive transcutaneous oxygen pressure diagnosis of reversed ductal shunts in cyanotic heart disease. Pediatrics 1980;66(1):22-25.
  32. de Geeter B, Messer J, Benoit M, Willard D. Right-toleft ductal shunt and transcutaneous PO2. Birth Defects 1979;15(4):387-392.
  33. Holmgren D, Redfors S, Solymar L. Transcutaneous- PO2 monitoring for detection of exercise-induced rightto- left shunts in children with congenital heart defects: a case report. Acta Paediatr 2001;90(7):816-818.
  34. Rauch DA, Ewig J, Benoit PE, Clark E, Bijur P. Exploring intermittent transcutaneous CO2 monitoring. Crit Care Med 1999;27(11):2358-2360.
  35. Guidelines for preventing the transmission of Mycobacterium tuberculosis in health-care facilities, 1994. Centers for Disease Control and Prevention. MMWR Recomm Rep 1994;43(RR-13):1-132.
  36. Bolyard EA, Tablan OC, Williams WW, Pearson ML, Shapiro CN, Deitchmann SD. Guideline for infection control in healthcare personnel, 1998. Hospital Infection Control Practices Advisory Committee. Infect Control Hosp Epidemiol 1998;19(6):407-463. Erratum in: Infect Control Hosp Epidemiol 1998;19(7):493.
  37. Boyce JM, White RL, Spruill EY, Wall M. Cost-effective application of the Centers for Disease Control Guideline for Prevention of Nosocomial Pneumonia. Am J Infect Control 1985;13(5):228-232.
  38. Merritt K, Hitchins VM, Brown SA. Safety and cleaning of medical materials and devices. J Biomed Mater Res 2000;53(2):131-136.

Interested persons may copy these Guidelines for noncommercial purposes of scientific or educational advancement. Please credit AARC and Respiratory Care Journal.

Reprinted from the September 2004 issue of RESPIRATORY CARE [Respir Care 2004; 49(9):1070–1072]

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