Reprinted from Respiratory Care (Respir Care 1994:39(12):1176-1179)

AARC Clinical Practice Guideline

Transcutaneous Blood Gas Monitoring for Neonatal & Pediatric Patients


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.(1-7)


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.(8)


4.1 The need to monitor the adequacy of arterial oxygenation and/or ventilation(9,10)
4.2 The need to quantitate the response to diagnostic and therapeutic interventions as evidenced by PtcO2 and/or PtcCO2 values(9-11)


In patients with poor skin integrity and/or adhesive allergy, transcutaneous monitoring may be relatively contraindicated.(9)


PtcO2 and/or PtcCO2 monitoring is considered a safe procedure, but because of device limitations, false-negative and false-positive results may lead to inappropriate treatment of the patient.(10,12,13) In addition, tissue injury may occur at the measuring site (eg, erythema, blisters, burns, skin tears).(1,8,10)


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 include
7.1.1 Technical: The procedure may be labor intensive, although newer designs make application quicker and simpler.(14) Prolonged stabilization time is required following electrode placement.(14,15) 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.(16) The theoretical basis for mandatory heating of the PtcO2 electrode is established.(2) Improper calibration is possible and may be difficult to detect.(17)
7.1.2 Clinical: The following factors may increase the discrepancy between arterial and transcutaneous values-- The presence of hyperoxemia (PaO2 > 100 torr),(12,13) The presence of a hypoperfused state (shock, acidosis),(8,18,19) Improper electrode placement or application,(8) Vasoactive drugs,(19) The nature of the patient's skin and subcutaneous tissue (skinfold thickness, edema).(8,20)
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.(8,17)
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.(10,21)
7.2.2 When disparity exists between trans-cutaneous and arterial values and the clinical presentation of the patient, possible causes should be explored before results are reported. Discrepancies may be reduced by monitoring at alternate sites, recalibration, or appropriate substitution of instruments. 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.(9)
8.2. Transcutaneous blood gas monitoring is appropriate for continuous and prolonged monitoring (eg, during mechanical ventilation, CPAP, and supplemental oxygen administration).(9,10)
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 circulation21-23) or to determine the response to oxygen challenge in the assessment of congenital heart disease.(21-23)


9.1 Results should reflect the patient's clinical condition (ie, validate the basis for ordering the monitoring).(3,5,7)
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 application(8)


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. So-called spot checks are not appropriate.(3,9,10)


No special precautions are necessary, but Universal Precautions (as described by the Centers for Disease Control) are recommended.(24,25)
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.
Perinatal-Pediatrics Guidelines Committee:

Lynne K Bower RRT, Chairman, Boston MA
Sherry L Barnhart RRT, Mattoon IL
Peter Betit BS RRT, Boston MA
Barbara Hendon BA RCP RRT, Wylie TX
Joanne Masi-Lynch BS RRT, Salt Lake City UT
Barbara G Wilson MEd RRT, Durham NC

  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: 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. American Academy of Pediatrics, Task Force on Transcutaneous Oxygen Monitors. Report of consensus meeting, Dec 5-6, 1986. Pediatrics 1989;83(1):122-126.
  9. Martin. RJ. Transcutaneous monitoring: instrumentation and clinical applications. Respir Care 1990;35(6):577-583.
  10. Lucey JF. Clinical uses of transcutaneous oxygen monitoring. Adv Pediatr 1981;28:27-56.
  11. Severinghaus JW. Transcutaneous blood gas analysis. Respir Care 1982;27(2):152-159.
  12. Huch R, Lübbers W, Huch A. Reliability of transcutaneous monitoring of arterial PO2 in newborn infants. Arch Dis Child 1974;49:213-218.
  13. 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.
  14. Kesten S, Chapman KR, Rebuck AS. Response characteristics of a dual transcutaneous oxygen/carbon dioxide monitoring system. Chest 1991;99:1211-1215.
  15. Marsden D, Chiu MC, Paky F, Helms P. Transcutaneous oxygen and carbon dioxide monitoring in intensive care. Arch Dis Child 1985;60:1158-1161.
  16. McLellan PA, Goldstein RS, Ramcharan V, Rebuck AS. Transcutaneous carbon dioxide monitoring. Am Rev Respir Dis 1981;124:199-201.
  17. Cassady G. Transcutaneous monitoring in the newborn infant. J Pediatr 1983;103(6):837-848.
  18. 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.
  19. Peabody JL, Gregory GA, Willis MM, Tooley WH. Transcutaneous oxygen tension in sick infants. Am Rev Respir Dis 1978;118:83-87.
  20. 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.
  21. Pearlman SA, Maisels MJ. Preductal and postductal transcutaneous oxygen tension measurements in premature newborns with hyaline membrane disease. Pediatrics 1989;83(1):98-100.
  22. Tateishi K, Yamanouchi I. Noninvasive transcutaneous oxygen pressure diagnosis of reversed ductal shunts in cyanotic heart disease. Pediatrics 1980;66(1):22-25.
  23. de Geeter B, Messer J, Benoit M, Willard D. Right-to-left ductal shunt and transcutaneous PO2. Birth Defects 1979;15(4):387-392.
  24. Centers for Disease Control. Update: Universal Precautions for prevention of transmission of human immunodeficiency virus, hepatitis B virus, and other blood-borne pathogens in health care settings. MMWR 1988;37:377-382,387-388.
  25. 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;13:228-232.


Guilfoile TD. Bedside monitoring of the acutely ill neonate: the impact of transcutaneous monitoring on neonatal intensive care. Respir Care 1986;31(6):507-513.

Herrell N, Martin RJ, Pultusker M, Lough M, Fanaroff A. Optimal temperature for the measurement of transcutaneous carbon dioxide tension in the neonate. J Pediatr 1980;97(1): 114-117.

Huch A, Huch R, Schneider H, Peabody J. Experience with transcutaneous PO2 (tcPO2 ) monitoring of mother, fetus and newborn. J Perinat Med 1980;8:51-72.

James LS. Development and clinical evaluation of blood gas sensors for continuous monitoring (adult and neonate), bulletin 1-49. U.S. Dept of Commerce National Technical Information Service 1976.

Kilbride HW, Merenstein GB. Continuous transcutaneous oxygen monitoring in acutely ill preterm infants. Crit Care Med 1984;12(2):121-124.

Palmisano BW, Severinghaus. Clinical accuracy of a combined transcutaneous PO2 -PCO2 electrode. Crit Care Med 1984;12:276.

Peabody JL, Willis MM, Gregory GA, Tooley WH, Lucey JF. Clinical limitations and advantages of transcutaneous oxygen electrodes. Acta Anaesthesiol Scand Suppl 1978;68:76-82.

Rome ES, Stork EK, Carlo WA, Martin RJ. Limitations of transcutaneous PO2 and PCO2 monitoring in infants with bronchopulmonary dysplasia. Pediatrics 1984;74:217-220.

Schlueter MA, Tooley WH. Right to left shunt through the ductus arteriosus in newborn infants. Pediatr Res 1980;8:354.

Tremper KK, Waxman K, Bowman R, Shoemaker WC. Continuous transcutaneous oxygen monitoring during respiratory failure, cardiac decompensation, cardiac arrest, and CPR. Crit Care Med 1980;8(7):377-381.

Tremper KK, Waxman K, Shoemaker WC. Use of transcutaneous oxygen sensors to titrate PEEP. Ann Surg 1981;193(2):206-209.

Wimberley PD, Frederiksen PS, Witt-Hansen J, Melberg SG, Friis-Hansen B. Evaluation of a transcutaneous oxygen and carbon dioxide monitor in a neonatal intensive care department. Acta Paediatr Scand 1985;74:352-359.

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

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