Evaluation of the Effect of Lung Recruitment and Positive End- Expiratory Pressure (PEEP) on Anesthesia Induced Atelectasis Using Lung Ultrasound
Condition: Anesthesia Induced Atelectasis
MeSH terms: Pulmonary Atelectasis
Study type: Interventional

Summary: 
      Atelectasis is a side effect of general anesthesia which can be found in all types of
      interventions and patients of all ages.1-3 The reported incidence of anesthesia- induced
      atelectasis in children varies, ranging from 12 to 42% in sedated and nonintubated patients
      5, 6 and from 68 to 100% in children with general anesthesia with tracheal intubation or
      laryngeal mask.

      The aim of this work is to evaluate the effect of lung recruitment on anesthesia induced
      atelectasis using intraoperative lung ultrasound.

      Objectives

        -  To determine the effect of recruitment on anesthesia induced atelectasis using lung
           ultrasound.

        -  To Estimate the change of Pao2 with anesthesia induced lung atelectasis.

        -  To Estimate the change of Pao2 with lung recruitment.

        -  To evaluate the feasibility of use of lung ultrasound as a tool to guide optimum lung
           recruitment.
    

Detailed description: 
      This a randomized control trial is designed to include 40 children aged from one to four
      years presented for major abdominal surgery.

      Forty patients meeting the inclusion criteria will be randomly assigned into to two equal
      groups:

      Group C (n= 20): Without recruitment maneuver (control group)

      Group REC (n= 20): recruitment group

      All children will be premedicated with oral midazolam 0.5mg/kg half hour before procedure and
      atropine at a dose of 0.01-0.02 mg/kg( IM). Continuous electrocardiogram (ECG) , pulse
      oximetry, non-invasive arterial blood pressure, and temperature monitoring will be applied
      and all patients will be induced with inhalational anesthetic using Sevoflurane+ oxygen(O2)
      with mac 2%. After deepening of the anesthesia, intravenous (I.V.) line will be inserted and
      fentanyl 2μg/kg, muscle relaxant will be given in the form of atracurium 0.5mg/kg and
      patients will be intubated by appropriate size of endotracheal tube.

      After induction of anesthesia all patients will be ventilated using pressure controlled mode
      targeting tidal volume 6-8 ml/kg with inspiratory to expiratory ( I: E) ratio 1:1.5, and Fio2
      1, baseline arterial blood gas will be withdrawn. Patients will be divided into two groups.
      Group (REC) recruitment group; in this group, lung recruitment manoeuvre will be performed in
      patients using continuous positive airway pressure( CPAP) (30) cm H2O for (40) seconds after
      induction of anesthesia then patient will be converted to pressure controlled mode again with
      PEEP 5 cm H2O22,23. In next assessment time, if still there are atelectatic areas recruitment
      will be repeated and patient will be maintained at PEEP 10 cm H2O till the end of surgery. In
      group (C) non recruitment group, patient ventilation will be maintained on aforementioned
      tidal volume without recruitment but with PEEP 5cm H2O.

      Lung ultrasound (LUS) LUS will be performed with the portable echograph MicroMax (SonoSite,
      M-turbo) using a linear probe of 3 to 6 MHz. Each hemithorax will be divided into six
      sections using three longitudinal lines (parasternal, anterior, and posterior axillary) and
      two axial lines, one above the diaphragm and another one 1 cm above the nipples.

      As LUS provides regional information, we will repeat the following examination sequence in
      each hemithorax and in all patients: (1) anterior, (2) lateral, and (3) posterior regions
      starting from the diaphragm (caudal lung) and moving toward the apex (cranial lung).13,14
      Each hemithorax will be assessed using the two-dimensional classical view placing the probe
      parallel to the ribs .24 (fig. 1).The LUS of a normal lung shows a lung sliding (caused by
      the respiratory movement of the visceral pleura relative to the fixed parietal pleura) and A
      lines (repetitive horizontal reverberation artifacts generated by air within the lungs
      separated by regular intervals, the distances of which being equal that between the skin and
      the pleural line.

      Patients demographic data will be collected; age, gender, weight, height, type of surgery and
      duration of surgery.

      Lung ultrasound examinations will be performed at different time-points immediately before
      induction of anesthesia, 5, 15 minutes following induction of general anesthesia, before
      extubation and after extubation at recovery room to detect and monitor atelectasis. Arterial
      blood samples will be collected simultaneously to measure Pao2.

      Atelectasis will be assessed by ultrasound using lung aeration score applied for each region.
      Lung score is four points (0 = normal lung, 1 = moderate aeration loss, 2 = severe aeration
      loss, 3 = complete aeration loss and consolidation) so, applying score for 12 regions
      bilateral will result in maximum score 36 and lowest score 0.

      The sum of surface area of atelectatic regions and the number of recruitment attempts to
      recruit atelectatic areas will be recorded.

      Other data as heart rate, systolic, diastolic and mean arterial blood pressure will be
      recorded at same measuring points and during recruitment.

      Assessment for incidence of pneumothorax and postoperative pulmonary complications like;
      postoperative lung collapse and postoperative pneumonia.

      Assessment the duration of postoperative hospital stay.
    

Intervention name(s): lung recruitment maneuver
Intervention type(s): Procedure
Intervention description(s): lung recruitment manoeuvre will be performed in patients using continuous positive airway pressure( CPAP) (30) cm H2O for (40) seconds after induction of anesthesia then patient will be converted to pressure controlled mode again with PEEP 5 cm H2O
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Quadruple (Participant, Care Provider, Investigator, Outcomes Assessor)
Primary purpose: Prevention