Validity of Transcutaneous Carbon Dioxide Pressure Measurement in ICU Patients

Kim,  Won; Oh,  Bum Jin; Ahn,  Ji Yun; Lee,  Young Ju; Koh,  Younsuck; Lim,  Chae Man; Lim,  Kyoung Soo

J Korean Soc Emerg Med > Volume 15(6); 2004 > Article

Original Article

Journal of The Korean Society of Emergency Medicine 2004;15(6): 446-451.

Validity of Transcutaneous Carbon Dioxide Pressure Measurement in ICU Patients

Won Kim, Bum Jin Oh, Ji Yun Ahn, Young Ju Lee, Younsuck Koh, Chae Man Lim, Kyoung Soo Lim

¹Department of Emergency Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea. wkim@amc.seoul.kr
²Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.

ABSTRACT

PURPOSE:
To evaluate the validity of noninvasive assessment of arterial carbon dioxide tension (PaCO2) by measuring transcutaneous CO2(tcPCO2) and analyse the factors associated with accuracy of tcPCO2 in intensive care unit (ICU) patients.
METHODS:
Forty ICU patients (26 males), mean age 59 years, were enrolled. The patients suffered from acute respiratory failure (PaO2/FiO2 ratio<200) due to pneumonia (n=7), chronic obstructive pulmonary disease (n=2), interstitial pneumonia (n=1) and sepsis (n=1). The other patients were 16 of medically ill and 13 of surgically ill patients. Arterial blood sample was taken after stabilization of tcPCO2 values for at least 3min. In 16 patients, we measured tcPCO2 values and analyzed arterial gas one day after.
RESULTS:
In all patients, there was significant correlation between tcPCO2 (43.6+/-3.2 mmHg) and PaCO2 (43.4+/-3.4 mmHg) (r=0.91, r2=0.826, F=22.338, p=0.000). The time until stabilization of tcPCO2 values were 6 min 32 sec (+/- min 23 sec) and there was no influence from presence of acute lung injury, diseases at admission (pulmonary or nonpulmonary) (p=0.299 and 0.066). There was significant correlation between pulse oximeter oxygen saturation and arterial blood oxygen saturation (SaO 2)(r2=0.403, p=0.000). Repeated measurement of transcutaneous blood gas assessment in medical patients showed no difference with tcPCO2 (p>0.100). Multiple regression analysis showed that respiratory rate was the only independent factor of the time of stabilization of tcPCO2 value (beta=1.001, p=0.009).
CONCLUSION:
In ICU patients, tcPCO2 could be an alternative PaCO2 measuring method in limited value.

Key words: Carbon dioxide, Partial pressure, Intensive care units