Assessment of tracheal temperature and humidity in laryngectomized individuals and the influence of a heat and moisture exchanger on tracheal climate

Abstract

Assessment of intratracheal temperature and humidity, and evaluation of HME effectiveness is feasible with the ACE. The tested HME significantly increases the intratracheal humidity, but decreases the intratracheal temperature. Relative humidity calculations suggest that increasing the thermal capacity of this rehabilitation device can further increase the heat and moisture exchange efficiency.

A New Heat And Moisture Exchanger for Laryngectomized Patients: Endotracheal Temperature and Humidity

“…More hygroscopic material increases the amount of water that can be stored and the total heat capacity, which provides warmer inspired air. As shown by Zuur et al, 17 the inspired air is almost saturated during the whole inspiration. Only increasing the temperature can further increase the humidity, so a higher inspiratory temperature facilitates a higher inspiratory humidity .…”

“…The Rplus had higher inspiratory humidity than Provox Normal, without the decrease in end-inspiratory temperature that Provox Normal (and also Provox HiFlow) is known to cause. 17,19 The Lplus had inspiratory humidity similar to Provox Normal, but without Provox Normal's temperature-lowering effect, which is due to the heat-consuming evaporation of water droplets during inspiration. This was an important argument for the redesign of Provox Normal, and our findings clearly show that Rplus and Lplus do not lower the end-inspiratory temperature.…”

“…4). Breaths that had a minimum-versus-maximum humidity difference of less than 2 mg H 2 O/L were assumed to be due to cardiac oscillations 17 and were merged with the adjacent breath. We graphically displayed the data as a check of the breath-identification procedure.…”

“…Because of evaporative cooling there is even a slight but important decrease in end-inspiratory temperature with the Provox Normal and the Provox HiFlow (Atos Medical, Hö rby, Sweden) (Ϫ1.5°C and Ϫ1.0°C, respectively). [14][15][16][17] Breathing resistance plays a more profound role in HMEs for laryngectomees than in anesthesiology HMEs. The breathing resistance of a laryngectomee HME should be comfortable, to promote adherence to therapy.…”

“…2). In laboratory experiments the humidification capacity of Rplus and Lplus appeared to be better than the previous-generation laryngectomy HMEs; however, in vitro measurements do not necessarily represent in vivo behavior, 17 so we designed an in vivo study to investigate endotracheal temperature and humidity with the Rplus and Lplus, and to assess their clinical feasibility and effects. We compared the Rplus and Lplus to the Stomvent (the first corrugated paper HME for laryngectomized patients; Atos Medical, Hörby, Sweden) and the Provox Normal, to improve our understanding of the effects of the different designs on heating and humidification capacity, and to develop suggestions for further HME improvement.…”