Can Transcutaneous CO₂ Tension Be Used to Calculate Ventilatory Dead Space? A Pilot Study

Table 1

Patient demographic and clinical characteristics ().

Mean age (years) ± SD	68.25 ± 6.36
Males	24
Types of cardiac surgery
Valve replacement	12
CABG	12
Valve + CABG	4
Aneurysm	2
Cardiopulmonary bypass status
On bypass	26
Off bypass	4
Mean APACHE II score ± SD	14.5 ± 3.92
Patient comorbidities^1
Cardiovascular	28
Respiratory	6
Endocrine	8
Neurology	3
Miscellaneous	4
Vasopressor or inotrope support	14
Mean tidal volume on ventilator^2 (mL) ± SD	660 ± 95.95
Mean (mm of Hg) ± SD	35.93 ± 5.19
Mean (mm of Hg) ± SD	39.73 ± 5.82
Mean shunt fraction ()^3	0.19 ± 0.08

Patients may have more than one comorbidity.
Miscellaneous comorbidities included cirrhosis, chronic kidney disease, HIV and malignancy.
All patients maintained on volume assist control mode of mechanical ventilation.
Measured only in 27 patients who had a pulmonary artery catheter.
Abbreviations: CABG: coronary artery bypass graft; APACHE: acute physiology and chronic health evaluation.