EIT - Electrical impedance tomography assessment of lung homogeneity in infants undergoing inguinal hernia surgery; a prospective cohort study

This study will use EIT (Electrical Impedance Topography) to define the patterns of tidal ventilation within the chest in infants undergoing inguinal hernia surgery with four different anaesthetic types, 1. spinal 2. caudal, sedation and high flow nasal oxygen 3. general anaesthesia with a supraglottic airway 4. general anesthesia with mechanical ventilation via an endotracheal tube. EIT is a non-invasive, radiation-free monitoring tool that allows real-time continuous imaging of ventilation at the bedside, measuring the impedance of the thorax through a belt placed around patient's chest. The belt will be placed on the patient by a member of the research team preoperatively. Five measurements will be taken, 1. preoperative baseline recording 2. after the commencement of anaesthesia just prior to knife to skin 3. at the end of surgical procedure prior to end anaesthesia (i.e when dressings being applied) 4. within 10 minutes from arrival to recovery/intensive care unit 5. just before discharge from recovery ward (or two hours post operatively if discharged directly from theatre to Neonatal Intensive Care/ Special Care Unit). The EIT device is not part of usual monitoring of infants in this setting and is being specifically utilised for this study to assess ventilation patterns.