Do we deliver the pressures we intend to when using a T-piece resuscitator?

BACKGROUND

A T-piece resuscitator (TPR) uses a built-in manometer to set the inflation pressures, but we are not informed what pressures are actually delivered distally. Aim of this study was to measure the proximal and distal pressures under different gas conditions when using a TPR.

METHODOLOGY/FINDINGS: A test lung was ventilated using a TPR (PIP 25 cmH₂O, PEEP 5 cmH₂O) with a gas flow rate of 8 L/min. A) Pressure delivered by six different TPRs was tested. To test variability 20 participants were asked to set PEEP and PIP pressures to 25/5 cmH₂O. B) PIP and PEEP were measured proximal and distal of the TPR when using standard tubing or heated tubing with or without a humidifier. In experiment A mean (SD) proximal PIP and PEEP of the TPRs were respectively 20.3 (0.3) cmH₂O (19.9-20.6 cmH₂O) and 4.9 (0.1) cmH₂O. When 20 participants set pressures; PIP 26.7 (0.5) cm H₂O and PEEP 5.9 (0.44) cmH2O were measured. Experiment B showed that the decrease of PIP between proximal and distal pressures was not clinically significant. However there was a significant decrease of PEEP using the standard tubing (5.1 (0.1) cmH₂O proximally versus 4.8 (0.2) cmH₂O distally; p<0.001) compared to, when using a humidifier with associated tubing and the humidifier turned on, 5.1 (0.1) proximally versus 3.9 (0.2) cmH₂O distally; (p<0.001).

CONCLUSION/SIGNIFICANCE: The accuracy of the built-in manometer of a TPR is acceptable. Most pressures set proximally are comparable to the actual pressures delivered distally. However, when using tubing associated with the humidifier PEEP decreases distally by 1.1-1.2 cmH₂O and users should anticipate on this.