Open AccessValidity of transcutaneous oxygen/carbon dioxide pressure measurement in the monitoring of mechanical ventilation in stable chronic respiratory failure
Author(s) -
Rosner V.,
Hannhart B.,
Chabot F,
Polu J.m
Publication year - 1999
Publication title -
european respiratory journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 4.021
H-Index - 241
eISSN - 1399-3003
pISSN - 0903-1936
DOI - 10.1034/j.1399-3003.1999.13e18.x
Subject(s) - carbon dioxide , oxygen , arterial blood , accuracy and precision , anesthesia , ventilation (architecture) , blood pressure , chemistry , biomedical engineering , medicine , meteorology , mathematics , statistics , physics , organic chemistry
The accuracy and precision of transcutaneous pressure measurements of oxygen ( P tc,O 2 ) and carbon dioxide ( P tc,CO 2 ) in the monitoring of nocturnal assisted ventilation in adult patients were evaluated. Transcutaneous measurements obtained with two analysers, Radiometer TINA‐TCM3 (R) and Kontron MicroGas‐7650 (K), were compared with arterial blood gases analysed in blood samples withdrawn simultaneously in 10 patients. Sensors were heated to 43°C. Measurements of trascutaneous blood gases and arterial blood gases were collected six times at 1‐h intervals. The data obtained with both instruments were similar and did not significantly change over the 5 h test period. Measurement of P tc,O 2 underestimated arterial oxygen tension ( P a,O 2 ) and this underestimation increased with the level of P a,O 2 (p<0.01). Measurements of P tc,CO 2 overestimated arterial carbon dioxide tension ( P a,CO 2 ) and this overestimation increased with the level of P a,CO 2 (p<0.05). These errors suggested an instrumental bias. Mathematical correction of this bias neutralized the error in accuracy and improved the precision ( sd of the differences transcutaneous blood gases ‐ arterial blood gases). An additional correction, suppressing the between‐subject scattering, improved the actual precision: precision was reduced from 1.9 to 0.8 kPa (14.4 to 5.7 mmHg) (R) and from 1.7 to 0.5 kPa (13.1 to 3.7 mmHg) (K) for oxygen, and from 1.0 kPa (7.8 mmHg) (R) and 0.7 kPa (5.6 mmHg) (K) to 0.4 kPa (3.2 mmHg) for carbon dioxide (R and K). In conclusion, with these two successive corrections, transcutaneous oxygen and carbon dioxide provide a reliable estimation of blood gases to monitor nocturnal ventilation in adults with chronic respiratory failure.