PT  - JOURNAL ARTICLE
AU  - Elizaveta Baranova
AU  - Zhanna Donina
AU  - Nina Aleksandrova
TI  - Central apnea following rapid onset and progression of hypoxemia. A pilot animal study
DP  - 2014 Sep 01
TA  - European Respiratory Journal
PG  - P4901
VI  - 44
IP  - Suppl 58
4099  - http://erj.ersjournals.com/content/44/Suppl_58/P4901.short
4100  - http://erj.ersjournals.com/content/44/Suppl_58/P4901.full
SO  - Eur Respir J2014 Sep 01; 44
AB  - Objectives: Acute effects of progressive hypoxia include central apnea attributed to respiratory and cardiovascular collapse, but the relative contributions of the central and peripheral effects in producing collapse of cardiorespiratory system is unclear.Aims: The purpose of this study is to examine the influence of acute progressive hypoxia on respiratory effort and cardiovascular variability during prompt gradual decrease oxygen content from normoxia up to gasping and apnea.Methods: We studied the dynamic response of tidal volume (VT), breathing rate (BR), minute lung ventilation (MLV), esophageal pressure (Pes), inspiratory occlusion pressure (P0.1), arterial oxygen saturation (SpO2), heart rate (HR), mean arterial blood pressure (MAP) in anesthetized Wistar rats. The inspired oxygen concentration (FIO2 ) decreased to 3% within 10 min.Results: The rapid reduction FIO2 up to 6% O2 cause hyperventilation with concomitant hypocapnia. Further reduction FIO2 (up to 3-4% O2)producesharp decrease MAP to 50±12%(P<0.05), HR to 27 ± 6% (P<0.05), gasping respiration and apnea. However Pes and P0.1prior to the point of apnea was higher than the initial values by 47 ± 8 % and 52±6% (P <0.05 respectively).Conclusions: We conclude that the decline respiratory effort did not have time to develop during the rapid onset and progression of hypoxemia in our model. Apnea results from direct inhibitory effect of hypoxia and concomitant hypocapnia on the respiratory and vasomotor centers.