A Comparative Study of Water Cystometry and CO 2 Cystometry

Comparison of the results obtained with medium-fill water cystometry and rapid-fill CO₂ cystometry were done in 102 consecutive patients. In 99 patients the cystometric diagnoses were identical. In 3 patients we found detrusor hyperreflexia with water but a normal cystometrogram with CO₂. We concluded that CO₂ cystometry gives as valid information as water cystometry. Volume at first desire to void, bladder capacity and bladder compliance is approximately 50% higher in water cystometry than in CO₂ cystometry in normal cystometries. In cases of detrusor hyperreflexia there were no important differences in bladder volume at first uninhibited detrusor contraction or in highest intra-vesical pressure during detrusor contraction.