Pre-operative MSU culture may help prevent, but stone culture helps predict, post-operative sepsis risk at PCNL Cetti RJ, Boucher L, Ranasinghe W, McCahy P Monash Medical Centre, Melbourne, Australia

 Percutaneous nephrolithotomy (PCNL) remains the preferred modality of treatment for large renal calculi >2cm [1]. Introduction [1] Turk C et al. EAU guidelines on Urolithiasis. Limited update 2014.

 PCNL has an estimated complication rate of 20.5%, including a risk of sepsis approaching 5% even in the presence of a sterile pre-operative urine, and with the routine use of peri-operative antibiotics [2]. Introduction [2] Labate G et al. J Endourol 2011.

 Intra-operative kidney stone culture may help in the post-operative septic patient to guide antibiotic treatment. Introduction Studyn= SIRS rate (%) +ve SC (%) +ve MSU (%) Stone Culture/Sepsis SensitivitySpecificityPPV Korets et al Gonen et al Mariappan et al Margel et al

 Intra-operative kidney stone culture may help in the post-operative septic patient to guide antibiotic treatment. Introduction Studyn= SIRS rate (%) +ve SC (%) +ve MSU (%) Stone Culture/Sepsis SensitivitySpecificityPPV Korets et al Gonen et al Mariappan et al Margel et al

 Intra-operative kidney stone culture may help in the post-operative septic patient to guide antibiotic treatment. Introduction

 The aim of this study was to evaluate the clinical benefit of pre-operative midstream urine culture (MSUC), stone analysis and stone culture (SC) in predicting sepsis risk at PCNL. Aim

 A prospective analysis of pre-operative MSUC; SC, stone analysis and sepsis for all patients undergoing PCNL at Casey hospital, Monash Health, between May 2013 and May Methods 2 or more of the following: Temp >38°C (100.4°F) or < 36°C (96.8°F) Heart Rate > 90bpm WBC > 12,000/mm 3, < 4,000/mm 3 Respiratory Rate > 20 or PaCO2 < 32 mm Hg AND: SBP <90 or SBP Drop ≥ 40 mm Hg of normal

 All patients were prospectively investigated with a MSUC. All patients with a positive result were prescribed appropriate antibiotics, and proceeded with PCNL when results were subsequently confirmed negative.  Ceftriaxone 1g or Gentamicin 2.5mg/kg, and Ampicillin 1g iv.  Antiseptic preparation was 10% povidone-iodine for the genitalia and 1% iodine/70%alcohol for the PCNL site. Methods

 PCNL was performed with a single track, undertaken in the Casey modified supine position [3] under one surgeon (PM). Methods McCahy P et al. J Endourol. 2013

Results Mean Age (yrs) Range Sex: M F Mean Stone size (mm) Range Stone Constituents (n): Urate Ca Oxalate Ca Oxalate Urate Cysteine Struvite 0 34 (65.4%) 6 (11.5%) 2 (3.8%) 10 (19.2%) Postop drainage (n): Truly tubeless 20Fr Nephrostomy and 6Fr stent 6Fr Stent 20Fr Nephrostomy Bowel Injury 11 (21.6%) 4 (7.8%) 33 (64.7%) 0%

 4 (7.5%) procedures were complicated with sepsis.  3/4 required intensive care treatment.  6 (11.2%) patients had a positive pre-operative MSUC. All were treated with appropriate pre-operative antibiotics. 5 (83.3%) of these patients still grew concordant pure growth micro-organisms from their stone culture, but none suffered post-operative sepsis.  13 (24.5%) patients had positive stone cultures, 8 of which had negative preoperative MSUC’s, including the 4/13 (30.8%) who developed post- operative sepsis. Results

SC +veSC -ve MSUC +ve516 MSU -ve Sensitivity of MSU to predict +ve stone culture: 38.5% Specificity of MSU to predict +ve stone culture: 97.5% PPV 83% NPV 83% Results- Predicting stone colonisation from preoperative MSUC.

Results- Predicting sepsis risk from stone culture. Sepsis +veSepsis –ve SC +ve4913 SC –ve Sensitivity of SC to predict sepsis: 100% Specificity of SC to predict sepsis: 81.6% PPV: 30.8% NPV: 100% Sensitivity of SC to predict sepsis: 100% Specificity of SC to predict sepsis: 81.6% PPV: 30.8% NPV: 100%

Stone Constituentn= +ve preop MSUC +ve SCSepsis Calcium Oxalate343 (8.8%)5 (14.7%)1 (2.9%) Ca Oxalate Urate6-2 (33.3%) Cysteine Struvite103 (30%)5 (50%)1 (10%) Results Statistically significant increased risk of stone colonisation in struvite compared to calcium oxalate stones (p=0.03) Increased risk of sepsis in mixed uric acid stones compared with pure calcium oxalate stones (p=0.05)

 Pre-operative MSUC is mandatory.  Pre-operative MSUC is, however, not sensitive for predicting positive stone culture and subsequent sepsis risk.  Stone culture should be mandatory, to help direct post-operative antibiosis. Particularly in those patients with urate and struvite calculi. Conclusions

 Sample size.  Tertiary referral.  Data on DM, obesity, transfusion, dual access, operative time. Limitations

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