Respiratory Alterations of Acid-base Equilibrium: Acute and Chronic Renal Response
Alterations of acid-base equilibrium are very common in critically ill patients. Thus, understanding their pathophysiology and the possible compensatory mechanisms acting in different organs may play an important role in better set the consequent clinical treatment. The lung and the kidney are the two principal actors of such regulations. Although the respiratory response to acid-base alterations is well understood, less information are available for what the renal system is concerned. Such lack of information is partially due to: 1) the historical consideration of the kidney as a "slow" organ, in response to variations in acid-base equilibrium; 2) the lack of a monitoring system to closely assess renal response.
Our group has recently developed a monitoring system aimed at analyzing, in a quasi-continuous and non-invasive manner (every 10 min) the urinary profile in terms of urinary pH and electrolyte concentrations (sodium, potassium, chloride, ammonium).
The investigators hypothesize that the renal system reacts to large as well as to minimal variations of the acid-base equilibrium (especially induced by a variation in the respiratory function) in a very fast way, modifying the urinary concentration (and therefore the urinary excretion) of ammonium and some electrolytes (especially chloride).
|Acute Respiratory Variations of Acid-base Equilibrium||Other: Increase minute ventilation Other: Decrease minute ventilation|
|Study Design:||Allocation: Non-Randomized
Intervention Model: Parallel Assignment
Masking: None (Open Label)
Primary Purpose: Basic Science
|Official Title:||Respiratory Alterations of Acid-base Equilibrium: Acute and Chronic Renal Response|
- Variations in urinary electrolyte concentrations and pH [ Time Frame: From 0 to 4 hours ]
|Study Start Date:||February 2012|
|Estimated Study Completion Date:||November 2015|
|Estimated Primary Completion Date:||November 2015 (Final data collection date for primary outcome measure)|
Minute ventilation will be increased of about 30% of baseline value, through an increase in respiratory rate
Other: Increase minute ventilation
Respiratory rate will be increase in order to have a 30% increase of minute ventilation
Minute ventilation will be decreased of about 30% of baseline value, through a decrease in respiratory rate
Other: Decrease minute ventilation
Respiratory rate will be decrease in order to have a 30% decrease of minute ventilation
To investigate the acute renal response to respiratory alterations of acid-base equilibrium in order to better understand the underlying physiological mechanisms and to evaluate the validity of a renal monitoring system to indirectly assess the effectiveness of the respiratory function.
To collect data on the chronic response of the renal system in patients affected by chronic obstructive pulmonary disease (COPD), as well as on the acute response to acute variation of the chronic respiratory acidosis characterizing patients affected by COPD exacerbation.
Mechanically ventilated patients will undergo controlled variation of the ventilatory setting (hyperventilation vs. hypoventilation) in order to induce a controlled reduction or increase in arterial partial pressure of carbon dioxide (and an increase or reduction of arterial pH), within normal range of pH (7.35 - 7.45) During the variations, urinary concentrations of electrolytes and pH will be monitored.
Please refer to this study by its ClinicalTrials.gov identifier: NCT01540916
|Terapia Intensiva Postoperatoria; Rianimazione Generale - Fondazione IRCCS Ca' Granda - Ospedale Maggiore Policlinico|
|Milan, Italy, 20122|
|Principal Investigator:||Pietro Caironi, MD||Fondazione IRCCS Ca' Granda, Ospedale Maggiore Policlinico|