Analysis of Risk Factors for Pulmonary Complications in Patients Undergoing Upper Pole Prone Percutaneous Nephrolithotomy (uPPCNL): A Single Center Experience

Abstract

Introduction: To determine the risk factors contributing to pulmonary complications among patients who undergo upper pole prone percutaneous nephrolithotomy (uPPCNL). This will serve as a guide to urologists who utilize uPPCNL among their patients, so that they may monitor them more closely for these events.

Methods: A retrospective chart review was done on all patients who underwent uPPCNL from January 2015 to December 2017. Patient characteristics (age, gender, BMI, co-morbidity) and stone demographics (Stone size, Guy’s Stone score, laterality, stone location) were summarized as well as intraoperative parameters inclusive of operative time, number of tracts, estimated blood loss, and length of hospital stay. Point biserial correlation and Pearson Chi-square for independent tests were used to identify the independent predictors of pulmonary complications.

Results: Nine hundred ninety-two patients underwent uPPCNL during the study period. Fifty-two (5.2%) had pulmonary complications. Sixty-seven pulmonary complications were tallied because some had two complications at one time. The most common was pleural effusion 35(48%), followed by atelectasis in 16(30%), hospital-acquired pneumonia 14(27%) and acute respiratory distress syndrome 2(4%). Forty-one (78.8%) and 11(21.2%) required medical and surgical interventions, respectively. Higher Guy’s stone scores, larger stone size, and longer hospital stay were significant predictors for developing pleural effusion. Patients with higher preoperative serum creatinine and longer hospital stay were significantly associated with surgical management (p < 0.05).

Conclusion: The incidence of pulmonary complications after uPPCNL is low and only a minority need surgical management. When risk factors are present, these patients need to be monitored closely so that a timely intervention may be done to avoid life-threatening consequences.