Abstract
In the following two-part study, we determined the efficacy of observation of the light glow to detect correct placement of the tracheal tube after lightwand-guided tracheal intubation via the intubating laryngeal mask (ILM). We also determined the efficacy of a protocol to correct oesophageal intubation in this situation. In study 1, 80 ASA 1–3, anaesthetized, paralysed patients were randomly assigned to have a tracheal tube, preloaded with a flexible lightwand, placed into either the trachea (n=40) or oesophagus (n=40) under laryngoscope guidance. A blinded observer experienced with the lightwand technique determined whether oesophageal or tracheal intubation had occurred by observation of the light glow. In study 2, 1000 patients, 400 of whom were included in a previous study, underwent flexible lightwand-guided intubation via the ILM. Placement of the tracheal tube in oesophagus or trachea was determined by observation of the glow and verified by capnography. Oesophageal intubation was corrected by adjusting the ILM position using a protocol comprising two adjusting manoeuvres. Observation, verification and correction were by experienced anaesthetists conducting the case. In study 1, oesophageal and tracheal intubation was correctly detected in 38/40 (95%) and 37/40 (92.5%) patients respectively. In study 2, oesophageal and tracheal intubation was correctly detected in 55/55 (100%) and 945/945 (100%) patients respectively. In 40/55 (73%) patients, tracheal intubation was successful at the second attempt and in 13/55 (24%) at the third or fourth attempt. In 2/55 (4%) patients, persistent oesophageal intubation occurred. The sensitivity, specificity and positive predictive value were 95%, 92.5% and 92.7% respectively in study 1, and were all 100% in study 2.