title: Impact of Extraperitoneal Dioxyde Carbon Insufflation on Respiratory Function in Anesthetized Adults: A Preliminary Study Using Electrical Impedance Tomography and Wash-out/Wash-in Technic.
abstract: BACKGROUND
  Extraperitoneal laparoscopy has become a common technique for many surgical procedures, especially for inguinal hernia surgery. Investigations of physiological changes occurring during extraperitoneal carbon dioxide (CO2) insufflation mostly focused on blood gas changes. To date, the impact of extraperitoneal CO2 insufflation on respiratory mechanics remains unknown, whereas changes in respiratory mechanics have been extensively studied in intraperitoneal insufflation.
  
  
  OBJECTIVE
  The aim of this study was to investigate the effects of extraperitoneal CO2 insufflation on respiratory mechanics.
  
  
  METHODS
  A prospective and observational study was performed on nine patients undergoing laparoscopic inguinal hernia repair. Anesthetic management and intraoperative care were standardized. All patients were mechanically ventilated with a tidal volume of 8 mL/kg using an Engström Carestation ventilator (GE Healthcare). Ventilation distribution was assessed by electrical impedance tomography (EIT). End-expiratory lung volume (EELV) was measured by a nitrogen wash-out/wash-in method. Ventilation distribution, EELV, ventilator pressures and hemodynamic parameters were assessed before extraperitoneal insufflation, and during insufflation with a PEEP of 0 cmH2O, 5 cmH20 and of 10 cmH20.
  
  
  RESULTS
  EELV and thoracopulmonary compliance were significantly decreased after extraperitoneal insufflation. Ventilation distribution was significantly higher in ventral lung regions during general anesthesia and was not modified after insufflation. A 10 cmH20 PEEP application resulted in a significant increase in EELV, and a shift of ventilation toward the dorsal lung regions.
  
  
  CONCLUSIONS
  Extraperitoneal insufflation decreased EELV and thoracopulmonary compliance. Application of a 10 cmH20 PEEP increased EELV and homogenized ventilation distribution. This preliminary clinical study showed that extraperitoneal insufflation worsened respiratory mechanics, which may justify further investigations to evaluate the clinical impact.
authors: Department of Anesthesia and intensive care, Sainte Anne Military Teaching Hospital, Toulon, France.
authors: Julien
authors: J
authors: Bordes
authors: Department of Anesthesia and intensive care, Sainte Anne Military Teaching Hospital, Toulon, France.
authors: Cecilia
authors: C
authors: Mazzeo
authors: Department of Anesthesia and intensive care, Sainte Anne Military Teaching Hospital, Toulon, France.
authors: Philippe
authors: P
authors: Gourtobe
authors: Department of Anesthesia and intensive care, Sainte Anne Military Teaching Hospital, Toulon, France.
authors: Pierre Julien
authors: PJ
authors: Cungi
authors: Department of Anesthesia and intensive care, Nord Hospital, Aix Marseille University Marseille, France.
authors: Francois
authors: F
authors: Antonini
authors: Department of Visceral Surgery, Sainte Anne Military Teaching Hospital, Toulon, France.
authors: Stephane
authors: S
authors: Bourgoin
authors: Department of Anesthesia and intensive care, Sainte Anne Military Teaching Hospital, Toulon, France.
authors: Eric
authors: E
authors: Kaiser
keywords: Anesthesia; Insufflation; Respiratory Mechanics; Tomography; Ventilation