Reducing kidney motion: optimizing anesthesia and combining respiratory support for retrograde intrarenal surgery: a pilot study

Abstract

Background One of the greatest challenges presented with RIRS is the potential for movement of the stone within the operative field associated with diaphragm and chest respiratory excursions due to mechanical ventilation. To overcome this challenge, we propose in this pilot study a new general anesthesia technique combining high frequency jet ventilation (HFJV) with small volume mechanical ventilation (SVMV). Data regarding safety, feasibility and surgeons’ impression was assessed. Methods Patients undergoing RIRS for kidney stones from November 2017 to May 2018 were prospectively recruited to participate in the study. In each case after the beginning of general anesthesia (GA) with mechanical ventilation (MV) surgeons were asked to assess the mobility of the operative field and conditions for laser lithotripsy according to the developed questionnaire scale. The questionnaire consisted of 5 degrees of assessment of kidney mobility and each question was scored from 1 to 5, 1 being very mobile (extremely poor conditions for dusting) and 5 completely immobile (Ideal conditions for dusting). After the assessment GA was modified with combined respiratory support (CRS), reducing tidal volume and respiratory rate (small volume mechanical ventilation, SVMV) and applying in the same time transcatheter high frequency jet ventilation (HFJV) inside the closed circuit. After beginning of CRS, surgeons were once again asked to assess the mobility of the operative field and the conditions for laser lithotripsy. Main ventilation parameters were recorded and compared in both regimens. Results A total of 38 patients were included in the study. The mean age was 49 (range 45–53) with a mean stone size of 10 mm (range 10–14) and Hounsfield unit of 1060 (range 930–1190). All patients underwent successful RIRS and no intraoperative complications occurred throughout the duration of the study. A statistically significant difference between ventilation parameters prior to and after CRS institution was detected in all cases, however their clinical impact was negligible. Despite this, assessment via the questionnaire scale point values varied significantly before and after the application of CRS and were 2.3 (2.1; 2.6) and 3.8 (3.7; 4.0) respectively ( p < 0.001). Conclusions The novel combined respiratory approach consisting of HFJV and SVMV appears to provide better conditions for stone dusting through reduced respiratory kidney motion and is not associated with adverse health effects or complications. Trial registration NCT03999255 , date of registration: 25th June 2019 (retrospectively registered).

Apnoea is not necessary for flexible ureteroscopy and lasertripsy of renal stones: a prospective study over 6 years

“…Lasering and retrieving renal calculi has an added challenge due to respiratory excursions and the associated movement of kidney that occurs during spontaneous breathing. Apnoea is used in ureteroscopy for this purpose to manipulate breathing, reducing respiratory induced renal movement and the literature has suggested that it might be beneficial for clinical outcomes [ 8 , 9 ]. In their paper, Gadzhiev et al showed that reducing renal movement with manipulation of general anaesthetic provided better conditions for stone dusting, and the surgeons using it had a high degree of satisfaction [ 9 ].…”

“…For this reason, temporary apnoea during the procedure is suggested and often practiced [ 8 ]. A recent study suggests that apnoea is not always mandatory, and the procedure can be safely done with apnoea [ 9 ]. While apnoea can help with the procedure, it can also lead to respiratory complications, longer operative duration and ultimately prolong the length of hospital stay [ 10 – 13 ].…”

“…To achieve apnoea, controlled ventilation with endotracheal (ET) intubation facilitated by propofol and neuromuscular block is often used [ 8 , 9 ]. In an era of limitations on healthcare resources and pressure on hospital beds, day-case procedures where the patient is discharged the same day would have significant financial reward, efficiency and patient flow benefit and potentially lead to increased patient satisfaction [ 14 , 15 , 16 ].…”