Urodynamic examination (UDS) is the primary method for assessing bladder storage and emptying function. By recording changes in the volume of bladder pressure (detrusor pressure), pathological and physiological explanations of the patient's clinical symptoms are made. At present, commonly used manometric catheters are liquid conduction manocimetry catheters (WFC) and gas conduction manocimetry catheters (ACCs). WFC is the most commonly used catheter in clinical practice. In recent years, ACC has been more and more widely used in clinical practice due to its simple operation, less pseudoimage and more in line with the requirements of hospital infection prevention and control. However, it is still controversial whether ACC can completely replace WFC and whether the pressure parameters measured by the two are identical. UDS is a common method for diagnosing and assessing bladder function in elderly benign prostatic hyperplasia (BPH). 
To investigate whether aerodynamic (ACC) can replace fluid urodynamic (WFC) and ACC to evaluate prostatic hyperplasia (BPH) in the elderly.

A total of 27 male patients with BPH (60-90 years old) were randomly selected for a prospective study, and aerourodynamic examination and hydrodynamic examination were performed on the same patient at the same time period, and the urodynamic pressure parameters recorded by the two groups were compared. The pressure values were compared with the Bland-Altman plot and the paired sample t-test, and the difference in abdominal pressure changes between the two groups was compared by the chi-square test.

The variation trend of WFC and ACC pressure measurement results was consistent, but in the three comparison points, the mean abdominal pressure (Pabd), end-filling pressure (Pves.fill) and maximum detrusor pressure (Pdet.void) measured by WFC and ACC were (25.3±8.5)cmH2O(1cmH2O=0.098kPa) and (32.5±5.3)cmH2O, (26.0±8.4)cmH2O and (32.6±5.0)cmH2O and (98.8± 32.8)cmH2O and (95.3±36.9)cmH2O were measured at significantly different pressures (P<0.05).

The correlation coefficients r r of abdominal pressure at the end of filling stage, detrusor pressure at the end stage of detrusor filling and maximum pressure during detrusor filling were 0.235, 0.396 and 0.833, all P<0.001). The average pressure measured by WFC UDS and ACC UDS is significantly different. The average Pabd.fill and Pves.fill recorded by ACC UDS are consistently higher than WFC UDS.

The pressure measured by ACC cannot represent the pressure measured by WFC, suggesting that the standard reference data of ACC needs to be established clinically. WFC abdominal pressure instability may be one of the factors contributing to the difference in detrusor pressure measured by the two manometry methods. The ACC pressure and WFC pressure results were in high agreement, suggesting that the former could also be used to assess changes in bladder function in older people with BPH.