LUS and Consequences of High FiO2 in Children
Condition: Perioperative/Postoperative Complications
MeSH terms: Postoperative Complications
Study type: Observational

Summary: 
      The purpose of this study is

        1. to evaluate effect of high FiO2 on the development of intraoperative atelectasis in
           mechanically ventilated children using LUS.

        2. to investigate the correlation between lung consolidation score and patient clinical
           variables including pulmonary mechanics, Sao2%, ABG, and perioperative respiratory
           complications.
    

Detailed description: 
      The WHO and United States centers for disease control and prevention (CDC) recently
      recommended the administration of 80% inspired oxygen fraction (Fio2) during and immediately
      after surgery performed with general anesthesia and endotracheal intubation.

      The recommendation was based on some data suggesting that intra-operative high Fio2 reduces
      incidence of surgical site infections.

      The dilemma of applying high or low perioperative FiO2 arises in daily practice of pediatric
      anesthesia because children are at increased risk of developing hypoxemia due to their
      physiological characteristics including smaller functional residual capacity and increased
      metabolic requirement compared with adult.

      However, considering that atelectasis occurs in most pediatric patients undergoing general
      anesthesia, it is important to titrate perioperative level of FiO2 to minimize the risk of
      developing atelectasis and hypoxemia.

      The use of FiO2 80% at induction and emergence, whilst limiting FiO2 to 35% during
      maintenance of anesthesia, may prevent the occurrence of atelectasis and ensure sufficient
      oxygenation.

      Conversely, the use of FiO2 100% at induction and emergence, which is reduced to FiO2 80%
      during maintenance of anesthesia, may increase the margin of safety to avoid hypoxemia.

      In children, the pulmonary consequences of using high FiO2 during general anesthesia have not
      been fully characterized over the early perioperative period. LUS has shown reliable
      sensitivity and specificity for diagnosis of anesthesia-induced atelectasis in children [7].
      It can identify children needing a recruitment maneuver to re expand their lung and help
      optimize ventilator treatment during anesthesia.

      Our hypothesis is that clinical data are necessary to validate the lung sonographic findings
      of atelectasis and negative consequences of administrating high perioperative oxygen
      concentration.
    

Intervention name(s): Lung ultrasound
Intervention type(s): Diagnostic Test
Intervention description(s): All children will be studied in the supine position. LUS will be performed with the portable device MicroMax (Sonosite, Bothell, Washington, USA) using a linear probe of 6 to 12 MHz. All ultrasound scans will be performed by the same anesthetist, who has experience of more than 30 lung ultrasound scans in pediatric patients. Each hemithorax will be divided into six regions, using three longitudinal lines (parasternal, anterior and posterior axillary) and two axial lines (one above the diaphragm and the other 1 cm above the nipples)
Other intervention name(s): Lung Sonar
Observational model: Cohort
Time perspective: Prospective
Sampling method: Probability Sample
Study population: 
        Age of 1-6 years.

          -  ASA physical status (I-II).

          -  Endotracheal intubation and mechanical ventilation.

          -  Elective non-abdominal and non-thoracic surgery

          -  lasting for more than 2 hours.