To  evaluate the four different alternatives to the classical cough test during a urodynamic study in the context of the COVID-19 pandemic.

Patients who needed to undergo a urodynamic study (UDS)  at the West China Hospital of Sichuan University between April 2021 and May 2021 were randomly selected according to the inclusion and exclusion criteria. UDS was performed using catheters with standard measurements and the  UDS equipment. During the UDS process, we used four alternative methods to the “cough test”: 1) quickly pressing the bladder area, 2) performing the Valsalva maneuver, 3) performing the Kegel maneuver, and 4) letting the patient close  their mouth while doing cough test. The "cough" waveform data were obtained and  compared with the classical cough test.

Thirty patients (19 men, 11 women) were included in the study. There was no statistical difference between the cough waveform induced by the Valsalva maneuver compared with the classical cough test (P=0.150), no statistical difference between cough with closing mouth and classical cough test(P=0.255), no significant difference between pressing quickly on the bladder area and classical method(P=0.087), and there was a significant difference between the data obtained by the Kegel maneuver and the classical method (P<0.05).  The average "cough" amplitude obtained was 73.14 ± 22.48 cm H2O, 66.17 ± 17.12 cm H2O, 82.93 ± 18.95 cm H2O, 26.50 ± 8.68 cm H2O, and 68.90 ± 20.32 cm H2O by the classical cough test, by quickly pressing the bladder area, by the Valsalva maneuver, by the Kegel maneuver , and by coughing with a closed mouth, respectively.

The data obtained by the classical cough test, by quickly pressing the bladder area, by performing the Valsalva maneuver, and by letting the patient close their mouth while doing the cough test were statistically different with that of the initial intravesical pressure  (P<0.05); however, there was a statistical difference between the data obtained by  performing the Kegel maneuver and the initial intravesical pressure (p=0.60). In this study, we found that several “cough waveforms” induced by “alternative approaches” often represent two different subtypes. For example, we found that the waveform induced by the Valsalva maneuver often appears in two types: the Type 3 waveform characterized by a  “towering shape” and “sharp shape”; and the Type 4 waveform characterized by a “platform shape.” We also found two subtypes in the waveforms induced by the Kegel maneuver : the Type 1 waveform characterized by a “low waveform shape” and the Type 2 waveform characterized by a “weak waveform shape”. All of the five methods could produce “cough” waveforms, but when compared with the waveform induced by classical cough tests, the waveform amplitude induced by the Kegel maneuver was generally smaller and sometimes more  difficult to observe and record. The Valsalva maneuver method can always produce a higher waveform amplitude than other methods. Compared to the “sharp shape” waveform obtained by the classical cough test, the waveform obtained by the Valsalva maneuver was a “high platform shape”. Waveforms obtained by coughing with a closed mouth and by quickly pressing  the bladder area were similar to those obtained by the classical cough test.

Through this study, we preliminarily verified that quickly pressing  the bladder area, performing the Valsalva maneuver, and letting the patient close their mouth while doing the cough test can obtain effective cough waveforms and amplitudes. They can all be alternative approaches to the classical cough test in the context of the COVID-19 pandemic .