Efficacy of Intraoperative Renal Stone Culture in Predicting Postpercutaneous Nephrolithotomy Urosepsis/Systemic Inflammatory Response Syndrome: A Prospective Analytical Study with Review of Literature

Abstract

Aim: To evaluate and study the efficacy of intraoperative renal stone culture (IOSC) in predicting postpercutaneous nephrolithotomy (PCNL) urosepsis (PPS) and systemic inflammatory response syndrome (SIRS). PPS is known to occur in patients despite negative preoperative midstream urine culture (MSUC).

Methods: After obtaining institutional ethics committee approval and informed consent, 78 selected patients undergoing PCNL were evaluated as per protocol for risk factors for SIRS criteria with MSUC, intraoperative renal pelvic urine culture (RPUC), and IOSC.

Results: MSUC was positive in six (7.7%) patients. The sensitivity, specificity, PPV, negative predictive value (NPV) and respiratory rate of MSUC for detecting SIRS were 20%, 93.15, 16.67%, 94.44%, and threefold, respectively. RPUC was positive in five (6.9%) patients with a specificity and NPV of 92.64% and 94.02%, respectively. IOSC positivity was seen in four (5.1%) patients with specificity and NPV of 94.5% and 3.2%, respectively. SIRS developed in five (6.4%) patients. MSUC, RPUC, and IOSC could not demonstrate any significant association with the occurrence of SIRS. Postoperative urine culture (POUC) was positive in 1/5 SIRS patients and no significant association (p < 0.182) could be demonstrated between the risk factors and PPS. Most complications were minor, while the mean hospital stay was significantly higher in SIRS patients.

Conclusions: While MSUC, RPUC, and IOSC were less sensitive in predicting the occurrence of SIRS/urosepsis in patients undergoing PCNL, nevertheless, we recommend routine IOSC for stone colonizing bacteria in at-risk select patients to predict potential PPS/SIRS. POUCs could be used in symptomatic SIRS to guide antimicrobial therapy in post-PCNL patients. Positive peri/intraoperative urine cultures may assist the urologist in directing appropriate antibiotics to prevent potential urosepsis in post-PCNL patients. Those with a higher blood transfusion rate and Clavien complications were at increased risk of PPS/SIRS. Escherichia coli was the most frequently isolated microbe followed by Klebsiella and Proteus, which were mostly sensitive to nitrofurantoin.

Keywords: PCNL; SIRS; post-PCNL sepsis; stone culture.