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Ventilatory sensitivity to CO 2 is altered by external breathing resistance (1092.10)
Author(s) -
Shykoff Barbara,
Warkander Dan
Publication year - 2014
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.28.1_supplement.1092.10
Subject(s) - ventilation (architecture) , mouthpiece , resistive touchscreen , breathing gas , cardiology , work of breathing , tidal volume , sensitivity (control systems) , medicine , anesthesia , respiration , respiratory system , breathing , meteorology , electrical engineering , anatomy , physics , engineering , dentistry , electronic engineering
CO 2 retention by divers underwater or by subjects exercising while breathing on a resistive circuit is uncorrelated with resting ventilatory sensitivity to CO 2 . We hypothesized that work of breathing might modulate sensitivity. Read’s rebreathing method was used to measure resting ventilatory sensitivity to CO 2 with no added resistance, inspiratory, expiratory, or both resistances. External resistors were two plugs with holes 0.56”, measured to cause work of breathing per tidal volume of 1 kPa with minute ventilation 100 L/min. Ventilation was measured with a turbine flow meter. CO 2 in the mouthpiece was monitored using a sector mass spectrometer. Preliminary data are available from 7 healthy Navy divers. Sensitivities are given in (L/min)/Torr for the initial increase in CO 2 ; some subjects showed increased sensitivity once CO 2 climbed. Median values were 1.9 without added resistance, 3.9 with inspiratory resistance, 2.3 with expiratory resistance, and 3.2 with both resistances. However, minima were 0.5 without resistance, 0.12 with inspiratory resistance, and negative with expiratory or both resistances. For all conditions, some subjects showed normal sensitivities only after CO 2 had climbed above 52 to 60 Torr, and some showed no ventilatory response. In this small sample, resting ventilatory sensitivity to CO 2 changed unpredictably with external resistance. Grant Funding Source : Supported by Naval Sea Systems Command Deep Submergence Biomedical Program