A Study of the Effect of Arterial Carbon Dioxide Tension on the Recovery of Spontaneous Respiration

The present study will use non-invasive respiratory inductance plethysmography(RIP) and transcutaneous carbon dioxide measurement to compare recovery of respiration under constant Transcutaneous carbon dioxide measurement( ptcCO2) with continuous high frequency jet ventilation HFJV (study method) with recovery of respiration during rising and apnea (current standard). The investigators hypothesize that the prolonged abdominal expiration that we observed during recovery of breathing in prior studies will be unaffected by arterial carbon dioxide (CO2) levels.