Serial manual bolus irrigation leads to critical intrarenal pressures during flexible ureterorenoscopy – time to abandon this manoeuvre

Objective

To characterise the effect of solitary and serial manual bolus irrigations on intrarenal pressures (IRPs) and observe the clinical consequences.

Patients and Methods

A pressure guidewire was used for IRP measurement during routine flexible ureterorenoscopy for management of renal stone disease, including manual bolus irrigation when required to maintain vision. The fluid bolus was either as a solitary manual bolus or a series of manual boluses in quick succession. The pre-bolus, maximal and difference between IRPs were calculated.

Results

A total of 50 procedures in 46 patients were analysed. In all, 68 solitary manual boluses and 38 serial manual boluses were observed to have been undertaken during these procedures. After a solitary manual bolus, the median (standard deviation [SD], range) increase in IRP was 22.4 (34.0, 0.1–160.8) mmHg, and the mean (SD, range) maximum IRP was 46.1 (41.7, 15.8–190.0) mmHg, with elevated IRPs persisting for a median (range) duration of 19 (4–66) s. After serial manual boluses, the median (SD, range) rise in IRP was 58.4 (64.7, 10.2–242.84) mmHg and the mean (SD, range) maximum IRP reached was 100.8 (69.7, 34.3–303.5) mmHg. The elevated IRPs endured for a median (range) of 42 (9–121 s; P < 0.01 in all comparisons), suggesting a much greater elevation of IRP with instances where serial bolus irrigation was undertaken.

Conclusions

Manual bolus irrigation, both solitary but particularly serial boluses, produces significant rises in IRP and could logically result in pyelovenous backflow and sepsis. We suggest that this manoeuvre should be avoided to reduce complications during ureterorenoscopy.