Spontaneous breathing with the use of a laryngeal mask airway in children: comparison of sevoflurane and isoflurane.

We compared respiratory parameters during anaesthesia with sevoflurane and isoflurane through a laryngeal mask airway (LMA). Children were anaesthetized with O2 and air with 2.3% (1MAC) sevoflurane (n = 20) or 1.5% (1MAC) isoflurane (n = 20). After insertion of LMA, patients were allowed to breathe spontaneously and respiratory rate (RR) and PECO2 were measured (presurgery state). After the measurement, anaesthetic concentration was increased to 1.3 MAC (3.0% sevoflurane or 2.0% isoflurane) and surgical stimulation was added. Fifteen min after incision, the measurements were again performed (during surgery). In the sevoflurane group, mean RR and PECO2 were 32 breaths.min-1, and 6.0 kPa (45 mmHg) respectively, before surgery, and 35 breaths.min-1 and 7.0 kPa (52 mmHg) during surgery. In the isoflurane group, mean RR and PECO2 were 32 breaths.min-1 and 6.1 kPa (46 mmHg) respectively, before surgery, and 37 breaths.min-1 and 6.7 kPa (52 mmHg) during surgery. There were no statistical differences between the two anaesthetic groups. Clinical respiratory and cardiovascular parameters during spontaneous breathing with LMA in children are similar during sevoflurane and isoflurane anaesthesia.