Pre-operative MSU culture may help prevent, but

stone culture helps predict, post-operative

sepsis risk at PCNLCetti 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

Study n= SIRS rate

(%)

+ve SC

(%)

+ve MSU

(%)

Stone Culture/Sepsis

Sensitivity Specificity PPV

Korets et al 2011 204 9.8 16.2 10.3 45.0 87.0 27.3

Gonen et al 2008 61 1.6 50 40 50.0 82.3 89.4

Mariappan et al 2005 54 37.0 35.2 11.1 73.7 81.8 70.0

Margel et al 2006 75 22 48.0 25.3 76.5 60.3 36.1

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

Introduction

Study n= SIRS rate

(%)

+ve SC

(%)

+ve MSU

(%)

Stone Culture/Sepsis

Sensitivity Specificity PPV

Korets et al 2011 204 9.8 16.2 10.3 45.0 87.0 27.3

Gonen et al 2008 61 1.6 50 40 50.0 82.3 89.4

Mariappan et al 2005 54 37.0 35.2 11.1 73.7 81.8 70.0

Margel et al 2006 75 22 48.0 25.3 76.5 60.3 36.1

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 2014.

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/mm3, < 4,000/mm3

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

ResultsMean Age (yrs)

Range

54

5-88

Sex:

M

F

 

31

22

Mean Stone size (mm)

Range

20.9

9-60

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%)

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 +ve SC -ve  

MSUC +ve 5 1 6

MSU -ve 8 39 47

  13 40 53

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 +ve Sepsis –ve  

SC +ve 4 9 13

SC –ve 0 40 40

  4 49 53

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 Constituent n= +ve preop

MSUC

+ve SC Sepsis

Calcium Oxalate 34 3 (8.8%) 5 (14.7%) 1 (2.9%)

Ca Oxalate Urate 6 - 2 (33.3%) 2 (33.3%)

Cysteine 2 - - 0

Struvite 10 3 (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

Questions?