Related Experiment Video
Updated: Jun 21, 2026

Surfactant Depletion Combined with Injurious Ventilation Results in a Reproducible Model of the Acute Respiratory Distress Syndrome (ARDS)
Published on: April 7, 2021
Decreasing pulmonary ventilation through bicarbonate ultrafiltration: an experimental study
Massimo Cressoni1, Alberto Zanella, Myra Epp
1National Institutes of Health, National Heart, Lung, and Blood Institute (MC, AZ, ME, IC, TK), Section of Pulmonary and Cardiac Assist Devices, Pulmonary and Critical Care Medicine Branch, Bethesda, MD, USA. mcressoni@hotmail.com
Objective:
: To demonstrate the technical feasibility of CO2 removal with a commercial hemofilter and a replacement solution containing sodium hydroxide to replace bicarbonate.
Design:
: Prospective animal experiment in sheep.
Subjects:
: Seven mixed-breed female sheep.
Interventions:
: Blood ultrafiltrate containing half of the metabolic production of CO2 was removed with a commercial hemofilter and a replacement solution containing sodium hydroxide was given as replacement. Minute ventilation was lowered to less than half of its baseline value. Ultrafiltration was stopped at 18 hrs, and Paco2 was allowed to increase for about 1 hr; at this time, the sheep were electively killed.
Measurements And Main Results:
: Every 6 hrs, blood was sampled from the carotid artery, the pulmonary artery, and from the extracorporeal perfusion circuit (before the hemofilter, immediately after the hemofilter, and after mixing with the replacement solution). To maintain normocapnia, minute ventilation was reduced from 3.8 +/- 0.1 L/min to 1.9 +/- 0.7 L/min; Paco2 remained near constant during the study. The average blood pH, after mixing with the replacement solution, was 7.64 +/- 0.12. One hour after the ultrafiltration had stopped, Paco2 had increased from 36.7 +/- 4.2 torr (4.9 +/- 0.6 kPa) to 59.6 +/- 9 torr (7.9 +/- 1.2 kPa) (p < .01) and blood pH had decreased from 7.317 +/- 0.041 to 7.151 +/- 0.051 (p < .01).
Conclusion:
: CO2 removal with bicarbonate ultrafiltration may be an effective treatment for patients with respiratory failure.
More Related Videos
Related Concept Videos
Bicarbonate-Carbonic Acid Buffer
Respiratory Regulation of Acid-Base Balance
When carbon dioxide levels increase in the blood, more H+ and HCO3⁻ are produced, leading to a...
Acute Respiratory Failure-III
Physiological Control of Respiration
Breathing, a seemingly passive process, is regulated by the respiratory center in the brainstem. This center coordinates the involuntary control of respirations, which means it occurs without conscious effort, ensuring a smooth and uninterrupted pattern.
Regulation of Ventilation
The body maintains ventilation by monitoring levels of carbon dioxide (CO2), oxygen (O2), and hydrogen ion concentration (pH) in the arterial blood. Among these factors, the level of CO2 plays a crucial...
Acute Respiratory Failure-V
Ensure that patients are monitored continuously for their response to therapy, including changes in...
Mechanical Ventilation III: Noninvasive Ventilation
Noninvasive Positive-Pressure Ventilation (NIPPV)

