Gasotransmitter profile among critically ill patients: A prospective cohort study

Background:

Endogenousgasotransmitters are small gaseous transmitters generated in the human body. Itis postulated that dysregulation in the gasotransmitter system contributes tothe pathophysiology of several disorders. (1,2) Critical illness often resultsfrom a cascade of exaggerated pro-inflammatory and anti-inflammatory responses,(3,4) some of which may be mediated by endogenous gasotransmitters. Therelevance and profile of these gasotransmitters in the context of criticalillness has however not been studied.

Studyobjectives:

1.      To describe the profile ofgasotransmitters hydrogen sulphide (H2S), hydrogen peroxide (H202) and nitricoxide (NO) among a cohort of critically ill adult patients admitted to atertiary care hospital in India.

2.      To describe the profile of thesegasotransmitters in distinct diagnostic groups such as Acute RespiratoryDistress Syndrome (ARDS), Sepsis, Trauma and Brain injury (traumatic andnon-traumatic).

3.      To identify gasotransmitterthresholds at admission (within first 24hrs) that are predictive of pooroutcomes for critically ill patients.

 Studypopulation:

Inclusioncriteria:

-       Alladult patients admitted to the ICU and anticipated to stay for at least 24hrs

-       Patientsshould be receiving organ support in the form of oxygen therapy (any device),vasopressors (any dose) or kidney replacement therapy (other than maintenancedialysis)

-       Patientsadmitted from the Emergency room or transferred from the in-patient wards(within 7 days from their original day of admission to the hospital) to the ICU

  Exclusioncriteria:

-       Patientsanticipated to survive <24hrs at the time of ICU admission

-       Patientsadmitted to an outside hospital for >48hrs prior to admission to ourhospital

 Variables:

The keyexposures will be the levels of gasotransmitters at the time of admission andthe key outcome will be ICU mortality. Secondary outcomes will include hospitalmortality, length of stay and receipt of organ support during ICU stay.

 Studyprocedures:

We willcollect blood samples for the measurement of all three gasotransmitters every8h for the first 24hrs and then once a day for the first 5 days of ICUadmission or until discharge or death (whichever is earlier). 1-3ml of blood isrequired for each analysis and efforts will be made to synchronize these blooddraws with the timing of any other blood tests in order to minimize discomfortto the patients.

Our grouphas developed bedside microfluid probes for the detection of thesegasotransmitters and we will be employing these devices for our measurements.