Percutaneous transtracheal high frequency jet ventilation (TTJV) in adults is frequently used during anaesthesia for laryngeal microsurgery. It provides excellent surgical operating conditions and safety for the patient. The technique has not been evaluated in infants and children. Accordingly, we studied 16 infants and children (mean age 5.5 +/- 3.8 yr, range 6 wk-12 yr) who underwent 28 consecutive endoscopic procedures with laser microsurgery of the glottic or subglottic space under general anaesthesia using a TTJV technique. All patients had a severe obstructive lesion of the larynx and/or upper trachea. The mean duration of the procedure was 70 +/- 27 min (range 30-140 min). Indications for TTJV were: subglottic stenosis: 5, haemangioma: 4, laryngeal papillomatosis: 5, pharyngeal cyst: 1, laryngomalacia: 1. Adequate control of the airway and satisfactory gas exchange were obtained in all cases. Surgery was performed without being impeded by anaesthetic equipment. Three complications occurred: one extensive surgical emphysema; one bilateral pneumothorax; one severe vagus-induced cardiovascular depression. Prompt and complete recovery without sequelae followed appropriate treatment. In 32% of the cases, the children were outpatients and in about half of the procedures (13/28) they left the hospital between the first and the third day. We conclude that percutaneous transtracheal jet ventilation is effective in paediatric endoscopic surgery. Procedures that might otherwise require a tracheostomy can be performed safely with this minimally invasive technique. Adequate indications and appropriate understanding of the technique and its potential problems are required for its correct application and successful use.