Springer Nature is making SARS-CoV-2 and COVID-19 research free. View research | View latest news | Sign up for updates

Monitoring of pH and PCO2 in children using the Paratrend 7 in a peripheral vein



To determine the accuracy of the Paratrend 7 monitor inserted into a peripheral vein in providing continuous measurements of PCO2 and pH in children with respiratory failure.


In a prospective, case series at a University based PICU in a tertiary referral hospital and following informed consent, the Paratrend 7 intra-arterial blood gas monitoring system was inserted through a peripheral intravenous cannula. When clinically indicated, an arterial blood gas (ABG) was obtained. The values of pH and PCO2 from the Paratrend 7 and the ABG were compared using linear regression analysis and Bland-Altman analysis.


Seventeen ABGs were obtained in the 4 patients. PaC02 ranged from 29 to 51 mmHg and the pH values from 7.16 to 7.50. Linear regression analysis for the:Paratrend 7 pHvs the ABG pH resulted in an r = 0.9678 and an r2 = 0.9367 (P < 0.0001). Linear regression analysis for the Paratrend 7 CO2 vs ABG CO2 resulted in an r = 0.8273 and an r2 = 0.6845 (P = 0.01). Using a Bland and Altman analysis, the bias ± precision of the PCO2 values was 3 ± 1.4 and 0.036 ± 0.02 for the pH values.


The pH and PCO2 values obtained from the Paratrend 7 monitor provide a clinically acceptable correlation with arterial values.



Déterminer la précision du moniteur Paratrend 7 inséré dans une veine périphérique pour la mesure continue de la PCO2 et du pH chez des enfants souffrant d’insuffisance respiratoire.


Étude prospective en série effectuée dans l’unité de soins pédiatriques d’un hôpital universitaire de soins tertiaires après l’obtention du consentement éclairé. Le moniteur de gaz artériel Paratrend 7 a été inséré à travers une canule endoveineuse périphérique. Lorsque la clinique le justifiait, une gazométrie artérielle était réalisée (GA), Les valeurs du pH et de la PCO2 obtenues avec le Paratrend 7 et celles de la gazométrie étaient comparées par analyse de régression linéaire et une analyse de Bland-Altman.


Dix-sept gazométries artérielles ont été réalisées chez 4 patients. La PaCO2 variait entre 29 et 51 mmHg et le pH entre 7,16 et 7,50. La régression linéaire pour le pH du Paratrend 7 vs la gazométrie accordait r = 0,9678 et r2 = 0,9367 (P < 0,0001). L’analyse de la régression linéaire du Paratrend 7 pour le CO2 vs la gazométrie artérielle accordait un r = 0.8273 et un r2 = 0,6845 (P = 0,01). Avec l’analyse de Bland et Altman, le biais ± la précision des valeurs de la PCO2 était 3 ± 1,4 et 0,036 ± 0,02 pour les valeurs de pH.


Les valeurs de pH et de PCO2 obtenues par le moniteur Paratrend 7 représentent une corrélation cliniquement valide des valeurs artérielles.


  1. 1

    Venkatesh B, Glutton Brock TH, Hendry SP. A multiparameter sensor for continuous intra-arterial blood gas monitoring: a prospective evaluation. Crit Care Med 1994; 22: 588–94.

  2. 2

    Roupie EE, Brochant L, Lemaire FJ. Clinical evaluation of a continuous intra-arterial blood gas system in critically ill patients. Intensive Care Med 1996; 22: 1162–8.

  3. 3

    Hillier SC, Badgwell JM, McLeod ME, Creighton RE, Lerman J. Accuracy of end-tidal PCO2 measurements using a sidestream capnometer in infants and children ventilated with the Sechrist infant ventilator. Can J Anaesth 1990; 37: 318–21.

  4. 4

    Tobias JD, Flanagan JFK, Wheeler TJ, Garrett JS, Barney C. Noninvasive monitoring of end-tidal C02 via nasal cannulas in spontaneously breathing children during the perioperative period. Crit Care Med 1994; 22: 1805–8.

  5. 5

    Whitesell R, Asiddao C, Gollman D, Jablonski J. Relationship between arterial and peak expired carbon dioxide pressure during anesthesia and factors influencing the difference. Anesth Analg 1981; 60: 508–12.

  6. 6

    Liu SY, Lee TS, Bongard F. Accuracy of capnography in nonintubated surgical patients. Chest 1992; 102: 1512–5.

  7. 7

    Yamanaka MK, Sue DY. Comparison of arterial-end tidal PCO2 difference and dead space/tidal volume ratio in respiratory failure. Chest 1987; 92: 832–5.

  8. 8

    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: 55–8.

  9. 9

    Cassady G. Transcutaneous monitoring in the newborn infant. J Pediatr 1983; 103: 837–48.

Download references

Author information

Correspondence to Joseph D. Tobias.

Rights and permissions

Reprints and Permissions

About this article

Cite this article

Tobias, J.D., Meyer, D.J. & Helikson, M.A. Monitoring of pH and PCO2 in children using the Paratrend 7 in a peripheral vein. Can J Anaesth 45, 81 (1998).

Download citation


  • Peripheral Vein
  • Altman Analysis
  • Status Asthmaticus
  • Tertiary Referral Hospital
  • Acceptable Correlation