Ventilation and breathing patterns during hemodialysis-induced carbon dioxide unloading

Area of Science:

• Nephrology
• Respiratory Physiology
• Cardiovascular Science

Background:

• Hemodialysis (HD) using acetate-buffered dialysate is known to cause significant carbon dioxide (CO2) unloading.
• This CO2 unloading is associated with alveolar hypoventilation, but the underlying mechanisms require further elucidation.

Purpose of the Study:

• To investigate the mechanisms of alveolar hypoventilation during HD.
• To analyze breathing patterns in end-stage renal failure patients undergoing HD with acetate-buffered versus bicarbonate dialysate.

Main Methods:

• Studied breathing patterns in 5 end-stage renal failure patients during HD.
• Utilized calibrated respiratory inductance plethysmography for continuous ventilation measurement.
• Analyzed arterial blood gas and expired air, comparing acetate and bicarbonate dialysate conditions.

Main Results:

• HD with acetate-buffered dialysate induced greater ventilation decrease compared to bicarbonate.
• Observed irregular breathing patterns, including prolonged expiratory time, tidal volume variations, apnea, and periodic breathing.
• These irregularities were linked to CO2 unloading, suggesting peripheral chemoreceptor-mediated ventilation.

Conclusions:

• Acetate-buffered HD triggers significant CO2 unloading, leading to altered and irregular breathing patterns.
• The observed breathing irregularities, including apnea and periodic breathing, are likely driven by CO2 unloading impacting peripheral chemoreceptor sensitivity.
• Ventilation control may become predominantly mediated by peripheral chemoreceptors during substantial CO2 loss in HD.