Stenosis following tracheostomy. A quantitative study of long term results.

Seventy out of the 320 patients treated with tracheostomy and respiratory care in an intensive care unit, were included in a follow-up study. A variety of surgical (38) and medical (32) conditions had prompted IPPV for 1-59 days; 33 had had primary and 37 secondary tracheostomies. The final study included an interview, physical examination, radiographic examination and spirometry. Using radiographic measures, the area of stenosis was calculated as well as the pressure drop across the stenosis at various flow rates. The methods of calculation were tested in one patient and compared with the actual tracheal pressure and gas flow recordings. Lateral stenosis was found in 69 and frontal stenosis in 25 patients, the length being 0-2-5-0 cm. The stenosis was situated at the level of the stoma in 59, at the cuff in 6, and at both sites in 2; in 2 the level could not be determined accurately. The mean area of normal trachea was 2-8+/-0-8 cm2 in females and 3-7+/-0-7 cm2 in males, while the stenotic area ranged from 0-86 to 4-54 cm2. A stenosis of potential functional significance was found in 8 patients (area less than 1-5 cm2). The stenotic area correlated well with the pressure drop across the stenosis and better than with the stenosis percentage (1-74%). The predicted pressure falls over the stenosis at different flow rates were in excellent agreement with those measured in one patient. Spirometry was unsuitable for detecting the stenosis. Poor correlation were found between the degree of tracheal stenosis and chronic respiratory disease, smoking, age, interval between intubation and tracheostomy, or duration of IPPV. Dysponea during moderate exercise was present in all patients who had a pronounced stenosis.