Effects of the mask and mouthpiece plus noseclip on spontaneous breathing pattern

Publisher Website
Google Scholar
Abstract
Studies of breathing patterns that use a mask (M) or mouthpiece plus noseclip (MP + NC) may contain artifacts due to the stimuli of the apparatus used. A canopy-spirometry-computer system was used to analyze respiratory patterns in a noninvasive manner. Changes in respiration induced by the application of M or MP + NC were analyzed. Twenty-two normal subjects and five critically ill patients were studied in (1) canopy alone, (2) canopy with M and (3) canopy with a MP + NC (in normal subjects only). An algorithm quantified each breath and determined tidal volume (VT), frequency (f), minute ventilation (V), O2 consumption (VO2), CO2 production (Vco2), sigh frequency (SF), ventilatory equivalent (VEco2 defined as V/Vco2), and tidal volume distribution (VTD) VTD that reflects the tendency to breathe in a relatively narrow range of tidal volumes and is quantified as VTD10, VTD20 (% breaths within ± 10% and ± 20% of mean VT). The M increased VT, V, VEco2 (presumbly secondary to its increased dead space) VTD10 and VTD20. MP + NC increased VT, V and decreased VTD10 and VTD20. Neither device affected SF. The M produced similar changes in the resting ventilation of both the patients and normal subjects. Our previous studies have shown that ill patients breathe at relatively fixed VT, i.e., high VTD10 and VTD20. Use of a M or MP + NC obscured this phenomenon and altered VT, V, and VEco2

This publication has 0 references indexed in Scilit: