Distal oesophageal pH measurement in children during general anaesthesia using the laryngeal mask airway^TM, tracheal tube and face mask

Background: Distal oesophageal pH was measured during controlled ventilation in children with the laryngeal mask airway (LMA^TM), tracheal tube (TT) and face mask (FM).

Methods: Fifty-six children scheduled for inguinal surgery with a standardized general anaesthetic technique were randomly allocated to receive LMA (n=21), TT (n=18) or FM (n=19). A 14 Fr pH probe was placed into the distal oesophagus and pH values were measured over 1 min at 2-min intervals during the first 20 min of anaesthesia.

Results: The median values of pH were 4.4 (3.5–5.5), 4.2 (3.3–4.9), 4.1 (3.2–5.1), 4.1 (3.3–5.0), 4.0 (3.3–4.9), 4.0 (3.4–5.1); 4.2 (3.3–5.1), 4.2 (3.6–5.0), 4.2 (3.5–5.0), 4.2 (3.5–5.2), 4.2 (3.5–5.0), 4.1 (3.5–5.0) and 4.2 (3.6–5.0), 4.2 (3.8–5.8), 4.1 (2.8–5.2), 4.2 (3.3–5.1), 4.2 (3.4–5.1), 4.3 (3.4–5.1) for LMA, TT and FM groups, respectively.

Conclusions: There was no difference in the median pH values, within and between the groups (P > 0.05). We conclude that there is no difference in gastro-oesophageal reflux, when using a LMA, TT or FM during controlled ventilation in anaesthetized children.