Respiratory Alterations of Acid-base Equilibrium: Acute and Chronic Renal Response

This study has been completed.
Information provided by (Responsible Party):
Fondazione IRCCS Ca' Granda, Ospedale Maggiore Policlinico Identifier:
First received: February 23, 2012
Last updated: June 22, 2015
Last verified: June 2015

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).

Condition Intervention
Acute Respiratory Variations of Acid-base Equilibrium
Other: Increase minute ventilation
Other: Decrease minute ventilation

Study Type: Interventional
Study Design: Allocation: Non-Randomized
Intervention Model: Parallel Assignment
Masking: Open Label
Primary Purpose: Basic Science

Further study details as provided by Fondazione IRCCS Ca' Granda, Ospedale Maggiore Policlinico:

Primary Outcome Measures:
  • Variations in urinary electrolyte concentrations and pH [ Time Frame: From 0 to 4 hours ] [ Designated as safety issue: No ]

Enrollment: 50
Study Start Date: February 2012
Study Completion Date: March 2015
Primary Completion Date: March 2015 (Final data collection date for primary outcome measure)
Arms Assigned Interventions
Experimental: Hyperventilation Other: Increase minute ventilation
Respiratory rate will be increase in order to have a 30% increase of minute ventilation
Experimental: Hypoventilation Other: Decrease minute ventilation
Respiratory rate will be decrease in order to have a 30% decrease of minute ventilation

Detailed Description:

Primary aim:

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.

Secondary aim:

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.

Study protol:

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.


Ages Eligible for Study:   16 Years and older
Genders Eligible for Study:   Both
Accepts Healthy Volunteers:   No

Inclusion Criteria:

  1. Presence of mechanical ventilation
  2. Presence of arterial and central venous line
  3. Presence of urinary catheter

Exclusion Criteria:

  1. acute or chronic renal failure with anuria
  2. presence of continuous renal replacement therapy
  3. hemodynamic instability
  4. less than 16 years of age
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Please refer to this study by its identifier: NCT01540916

Terapia Intensiva Postoperatoria; Rianimazione Generale - Fondazione IRCCS Ca' Granda - Ospedale Maggiore Policlinico
Milan, Italy, 20122
Sponsors and Collaborators
Fondazione IRCCS Ca' Granda, Ospedale Maggiore Policlinico
  More Information

No publications provided

Responsible Party: Fondazione IRCCS Ca' Granda, Ospedale Maggiore Policlinico Identifier: NCT01540916     History of Changes
Other Study ID Numbers: 842
Study First Received: February 23, 2012
Last Updated: June 22, 2015
Health Authority: Italy: Ethics Committee

Keywords provided by Fondazione IRCCS Ca' Granda, Ospedale Maggiore Policlinico:
acid-base equilibrium
renal system
urinary electrolytes processed this record on October 13, 2015