Rational airway control with high-frequency jet ventilation for percutaneous tracheostomy in patients with short fat neck

Background and goal

Percutaneous tracheostomy (PCT) is a well-established bedside procedure for critically ill patients (CIP). Several techniques of airway control and ventilation during PCT have been suggested. Standard mechanical ventilation (SMV) through an endotracheal tube (ETT) is widely used. Short fat neck (SFN) is considered a relative contraindication for PCT, mainly because of the possibility for airway complications during the procedure: loss of airway control, massive air leak, and sudden desaturation. We decided to examine our experience of airway control and ventilation by SMV and by high-frequency jet ventilation (HFJV) during PCT in the CIP with SFN and to determine which is more effective and reliable.

Materials and methods

From January 1998 to June 2000, a group of 23 CIP with SFN underwent PCT by the Griggs technique and SMV, and from July 2000 to November 2001 a group of 25 patients underwent PCT by the same technique but with HFJV. One trained team performed all the bedside PCT under general anesthesia (GA). In the HFJV group, a Cook catheter was inserted through the existing ETT into the upper part of trachea and HFJV was initiated by the special ventilator AMS-1000 ACUTRONIC with the following parameters: FiO₂ = 0.8–1.0, Vt = 160–200 cm³, I/E ratio = 0.5, respiratory rate = 100 bpm, driving pressure = 1.6–2.6 bar. Then the ETT was withdrawn from the trachea and larynx into the mouth along the ventilation catheter and PCT was performed. When PCT was finished the Cook catheter was removed together with the ETT. During PCT continuous routine monitoring and repeated blood gases were performed.

Results

There was no significant statistically difference between the two groups in the sizes of the neck (mean 47.1 vs 47.3 cm, median 47 vs 47 cm, range 45–51 vs 47–53 cm, P = 0.9) and distance between the cricoid and sternal notch (mean 1.35 vs 1.37 cm, median 1.35 vs 1.5 cm, range 0.5–1.9 vs 0.5–1.9 cm, P = 0.8). Duration of the procedure for the two groups was identical: mean = 10.7 min, median = 11 min, range = 10–12 min. When SMV was used, only in 11 from 23 patients was it possible to create good conditions for performance of PCT. Impaling of the ETT and cuff rupture happened in one case, and displacement of the ETT into the pharynx took place in three cases (due to a short larynx). Moderate air leak from the larynx around the ETT accompanied almost every procedure. Additional egress of air from the tracheotomy site during the time of the dilation was the reason for pronounced desaturation in seven patients. On the contrary, PCT with HFJV passed smoothly: a small air leak from tracheotomy site during its dilation did not influence the level of oxygenation, only an increase in PaCO₂ values within acceptable limits was found. The difference between SMV and HFJV was statistically significant (P < 0.001).

Conclusion

SMV cannot always supply the necessary conditions for PCT in patients with SFN and there are possibilities for development of serious complications. HFJV through a Cook catheter provides optimal conditions for manipulation on SFN, secures success of the procedure and prevents potential airway complications.