Acute hyperventilation increases the central venous-to-arterial PCO2 difference in stable septic shock patients

摘要

BackgroundTo evaluate the effects of acute hyperventilation on the central venous-to-arterial carbon dioxide tension difference (?PCO₂) in hemodynamically stable septic shock patients. MethodsEighteen mechanically ventilated septic shock patients were prospectively included in the study. We measured cardiac index (CI), ?PCO₂, oxygen consumption (VO₂), central venous oxygen saturation (ScvO₂), and blood gas parameters, before and 30?min after an increase in alveolar ventilation (increased respiratory rate by 10?breaths/min). ResultsArterial pH increased significantly (from 7.35?±?0.07 to 7.42?±?0.09, p p 2 (from 93 [76–105] to 112 [95–134]?mL/min/m2, p =?0.002) was observed in parallel with the increase in alveolar ventilation. While CI remained unchanged, acute hyperventilation led to a significant increase in ?PCO₂ (from 4.7?±?1.0 to 7.0?±?2.6?mmHg, p 2 (from 73?±?6 to 67?±?8%, p 2 ( r =?0.67, p =?0.002). Interestingly, we found a strong association between the increase in VO₂ and the increase in ?PCO₂ ( r =?0.70, p =?0.001). ConclusionsAcute hyperventilation provoked a significant increase in ?PCO₂, which was the result of a significant increase in VO₂ induced by hyperventilation. The clinician should be aware of the effects of acute elevation of alveolar ventilation on ?PCO₂.