Effect of tracheostomy tube on work of breathing: Comparison of pre- and post-decannulation

Abstract

Objective: To describe and compare the work of breathing (WOB) during spontaneous breathing under four conditions: (1) breathing through a tracheostomy tube with an inflated cuff, (2) breathing through the upper airway (UA) with a deflated cuff and occluded tube, (3) breathing through the UA with an occluded cuffless tube, and (4) postdecannulation.

Patients and methods: Patients who tolerated an occluded cuffless tube were included. Ventilatory variables and esophageal pressure were recorded. The pressure-time product (PTP), PTP/min, and PTP/min/tidal volume (PTP/min/VT) were measured. Each condition was measured for 5 min with a 15 min time interval between evaluations. Quantitative data are expressed as mean ± standard deviation. Single-factor analysis of variance was used, and the Games-Howell test was used for post hoc analysis of comparisons between group means (P ≤ 0.05).

Results: Eight patients were studied under each of the four conditions described above. Statistically significant differences were found for PTP, PTP/min, and PTP/min/VT. In the post hoc analysis for PTP, significant differences among all conditions were found. For PTP/min, there was no significant difference between Conditions 2 and 4 (P = 0.138), and for PTP/min/VT, there was no significant difference between Conditions 1 and 2 (P = 0.072) or between Conditions 2 and 3 (P = 0.106). A trend toward a higher PTP, PTP/min, and PTP/min/VT was observed when breathing through a cuffless tracheostomy tube.

Conclusion: The four conditions differed with respect to WOB. Cuff inflation could result in a reduced WOB because there is less dead space. Cuffless tracheostomy tubes generate increased WOB, perhaps due to the material deformity caused by body temperature.

Keywords: Airway care; airway extubation; artificial airway; decannulation; extubation methods; tracheostomy; work of breathing.

Figure 1

Ventilatory variables among conditions. ^¶Values expressed in means; Condition 1: inflated cuff; Condition 2: deflated cuff with occluded tube; Condition 3: occluded cuffless tube; Condition 4: upper airway. In the post hoc analysis, all the conditions showed a statistically significant difference among each except for *Condition 3 versus Condition 4, P = 0.945 and **Condition 3 versus Condition 4, P = 0.324

Figure 2

Work of breathing in different conditions. ^¶Values expressed in mean; Condition 1: inflated cuff; Condition 2: deflated cuff with occluded tube; Condition 3: occluded cuffless tube; Condition 4: upper airway; ^¥pressure-time product; ^#pressure-time product per minute; ^¥pressure-time product per minute/tidal volume. In the post hoc analysis all the conditions showed a statistically significant difference among each except for *Condition 2 versus condition 3, P = 0.053; *Condition 2 versus condition 4, P = 0.138; *Condition 1 versus condition 2, P = 0.072; ****Condition 2 versus Condition 3 P = 0.106