title: Analysis of the factors affecting blood loss in percutaneous nephrolithotomy: a registry of the Spanish Association of Urology in the supine position.
abstract: OBJECTIVE
  Percutaneous nephrolithotomy (PCNL) is the minimally invasive procedure of choice for removing renal stones larger than 2 cm. This study has aimed to identify the different variables that might influence decrease of hemoglobin during the surgery performed in supine position.
  
  
  METHODS
  A prospective, multicenter, observational study of supine PCNL, based on the Spanish Association of Urology database, was analyzed. The different preoperative and postoperative factors that might affect the decrease of hemoglobin were assessed: demographics and anthropometric data, comorbidities, size and location of the stones, anatomical variants and technical aspects of the procedure.
  
  
  RESULTS
  From September 2008 to December 2012, 397 supine PCNL procedures performed in 15 Spanish centers were registered. Mean hemoglobin decrease was 2.3±1.5 g/dl and overall blood transfusion rate was 5.5%. No statistically significant differences were found between genders, body mass index (BMI) and age in terms of blood loss. There were also no differences between patients with cardiovascular, hypertensive, diabetic and anticoagulant treatment background. Blood loss was not significantly influenced by stone size and location. Technical aspects of the procedure as operative time (> 120 min ≤), access to the pelvi-caliceal system (ultrasound, fluoroscopy), percutaneous tract dilation technique (Alken, balloon or Amplatz) or placement of nephrostomy (tube versus tubeless) were not associated with differences in pre-op/post-op hemoglobin. Only multiple percutaneous tracts (≥2) and middle calix access were statistically significantly (P=.03 and P=.01) related with less blood loss.
  
  
  CONCLUSIONS
  PCNL in supine position is a minimally invasive procedure for removal of large (≥2 cm) and multiple renal stones, with a low incidence of blood loss and minimal transfusion rate. Multiple percutaneous tracts and middle calix puncture were the only statistically significant variables associated with decrease in hemoglobin levels.
authors.affiliation: Servicio de Urología, Hospital Universitario de Getafe, Madrid, España. Electronic address: frfata@hotmail.com.
authors.forename: F
authors.initials: F
authors.lastname: Ramón de Fata
authors.forename: D
authors.initials: D
authors.lastname: Pérez
authors.forename: L
authors.initials: L
authors.lastname: Resel-Folkersma
authors.forename: J A
authors.initials: JA
authors.lastname: Galán
authors.forename: A
authors.initials: A
authors.lastname: Serrano
authors.forename: A
authors.initials: A
authors.lastname: Servera
authors.forename: M
authors.initials: M
authors.lastname: Arrabal
authors.forename: J L
authors.initials: JL
authors.lastname: Álvarez-Ossorio
authors.forename: R
authors.initials: R
authors.lastname: Ballestero
authors.forename: E
authors.initials: E
authors.lastname: Cao
authors.forename: M
authors.initials: M
authors.lastname: Arzoz
authors.forename: P
authors.initials: P
authors.lastname: Navarro
authors.forename: M
authors.initials: M
authors.lastname: Rigabert
authors.forename: J M
authors.initials: JM
authors.lastname: Sánchez-Zalabardo
authors.forename: F
authors.initials: F
authors.lastname: Lista
authors.forename: J C
authors.initials: JC
authors.lastname: Angulo
authors.forename: J H
authors.initials: JH
authors.lastname: Amón-Sesmero
mesh_terms: D016063:Blood Loss, Surgical / Q000706:statistics & numerical data*; D005260:Female; D006801:Humans; D007669:Kidney Calculi / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D009403:Nephrostomy, Percutaneous; D056888:Patient Positioning; D011446:Prospective Studies; D012042:Registries; D012955:Societies, Medical; D013030:Spain; D016683:Supine Position; D014572:Urology
keywords: Hemorragia; Hemorrhage; Kidney stones; Litiasis renal; Nefrolitotomía percutánea; Percutaneous nephrolitotomy; Posición supina; Supine position; Transfusion; Transfusión