Effects of Pneumoperitoneum on Dynamic Alveolar Stress-strain in Anesthetized Pediatric Patients
Condition: Atelectasis
MeSH terms: Pneumoperitoneum; Pulmonary Atelectasis
Study type: Observational

Summary: 
      General anesthesia is associated with loss of pulmonary functional residual capacity and
      consequent developement of atelectasis and closure of the small airway. Infants and young
      children are more susceptible to this lung collapse due to their small functional residual
      capacity.

      Mechanical ventilation in a lung with reduced functional residual capacity and atelectasis
      increased the dynamic alveolar stress-strain inducing a local inflammatory response in
      atelectatic lungs areas know as ventilatory induced-lung injury (VILI). This phenomenon may
      appear even in healthy patients undergoing general anesthesia and predisposes children to
      hypoxemic episodes that can persist in the early postoperative period. During laparoscopy,
      pneumoperitoneum may aggravate the reduction of functional residual capacity as it generates
      a further increase in intra-abdominal pressure.

      The increase in alveolar stress-strain cloud be reduced during pneumoperitoneum in theory, if
      normal functional residual capacity is restored and the transpulmonary pression is reached at
      the end of expiration of 0-1 cmH2O.
    

Detailed description: 
      This is a prospective and observational study designed to measure transpulmonary pressure
      during pneumoperitoneum. The investigators will studied 20 mechanically ventilated pediatric
      patients schedule for abdominal laparoscopy surgery under general anesthesia.

      Lung mechanics will be assessed during laparoscopy. Esophageal pressure will be measured by
      an esophageal ballon to measure transpulmonary pressure. Lung collapse will detected when
      transpulmonary pressure became negative and using lung ultrasound images. A lung recruitment
      maneuver will be applied if these patients present atelectasis during surgery. The optimal
      level of positive end-expiratory pressure (PEEP) if defined as the PEEP level when
      transpulmonary pressure remains positive during the PEEP titration trial of the recruitment
      maneuver.
    

Intervention name(s): Measure the transpulmonary pressure in pediatric patients
Intervention type(s): Other
Intervention description(s): Esophageal pressure will be measured by an esophageal ballon to assess transpulmonary pressure during laparoscopy surgery. Lung collapse will detected when transpulmonary pressure became negative and using lung ultrasound images. Lung ultrasound examinations will be performed at different times-points: after anesthesia induction, 10 minutes after pneumoperitoneum insufflation, and at the end of surgery. A lung recruitment maneuver will be applied if these patients present atelectasis during surgery.
Observational model: Cohort
Time perspective: Prospective
Sampling method: Non-Probability Sample
Study population: 
        Pediatric patients aged 3 to 7 years old, schedule for abdominal laparoscopy surgery under
        general anesthesia with tracheal intubation
      
Keywords: Children; Ultrasound