Pressure-volume relationship for paediatric cuffed tracheal tube

OBJECTIVE: Define the pressure-volume relationship of the cuff of paediatric cuffed tracheal tubes. STUDY DESIGN: Experimental study. MATERIALS AND METHODS: The cuff pressure was measured after incremental 0.1 ml filling volumes for 6 sizes (3.0 to 5.5 mm of internal diameter) of paediatric high volume-low pressure cuffed-tracheal tubes. The pressure-volume relationship of the cuff was assessed with and without resistance to the filling. Results were expressed with medium +/- SD. RESULT: Each increment increased the cuff pressure, without resistance, of 7.3 +/- 1.7 mmHg for sizes 3.0, 3.5 and 4.0, 4.8 +/- 1.6 mmHg for size 4.5, and 2.3 +/- 0.9 mmHg for sizes 5 and 5.5. The resistance decreased the filling volume of the cuff for each size of tracheal tubes. CONCLUSION: The margin of safety provided by cuff of smallest cuffed tracheal tubes is too small. Then, the smallest sizes (3.0 to 4.5) should not be called low pressure-high volume cuff.