Triple H ODC Trial
Condition: Hypoxia; Hypothermia, Accidental; Hypercapnia; Avalanche, Landslide, or Mudslide
MeSH terms: Hypoxia; Hypothermia; Hypercapnia
Study type: Interventional

Summary: 
      In an avalanche burial with an air pocket hypercapnia (and hypoxia) develops within few
      minutes, hypercapnia increases the rate of cooling and therefore the development of
      hypothermia. The Triple H Syndrome (Hypoxia, Hypercapnia, Hypothermia) occurs. This specific
      combination of the three parameters is unique for avalanche burial with an air pocket. Every
      single parameter has a substantial effect on the hemoglobin-oxygen dissociation curve, but
      until now no study described the combination of these three parameters. This curve will be
      measured under these specific conditions in a specifically developed in vitro model, to
      quantify its shifts and to show if there are combined effects of pCO2 and temperature. The
      newly developed method will be validated in comparison with an established method. The
      project will be performed with whole blood, drawn by healthy volunteers, in an experimental
      setting. The samples will be blinded to the investigator and analyzed in a randomized manner.
    

Detailed description: 
      The ODC is a function of pO2 and SO2. pO2, the independent variable, is plotted on the x
      axis, SO2 on the y axis. For the determination of this function, a pairwise measurement of
      pO2 and the corresponding SO2 is to be performed. Using nonlinear regression analysis, the
      ODC can be fitted to the measured points that describe the relation of pO2 and SO2 and
      characteristic parameters like p50 value and inflection points can be calculated.

      To measure the ODC under the conditions of the Triple H Syndrome (Hypoxie, Hypercapnia,
      Hypothermia), the temperature and the pCO2 have to be changed and controlled during the
      measurement. No commercially available instrument is able to obtain this. Therefore, we
      envisaged the development of an entirely new approach.

      In the 3H ODC trial venous blood will be drawn from 18 - 40 years old female and male
      volunteers by a unique venipuncture. The participants have to be in a fasted situation, ASA I
      and nonsmokers. The blood sample will be immediately pseudonymized and stored on ice and a
      venous blood gas analysis will be carried out (pH, Hb, COHb, MetHb, FHb). Simultaneous to the
      main measurement, 2,3 BPG will be quantified by an ELISA test and any unknown
      hemoglobinopathy will be excluded by Hemoglobin Electrophoresis. In the 3H ODC trial 4
      different pCO2 levels and 4 different temperatures will be analyzed in the resulting 16
      combinations. In each round a lot of ODCs will be measured, the measurement chamber will be
      filled with participants blood samples in a randomized manner. After the measurements, the
      blood samples will be discarded.
    

Intervention name(s): blood sampling
Intervention type(s): Other
Intervention description(s): venous blood sampling for oxygen affinity in-vitro test
Intervention model: Factorial Assignment
Intervention model description: 16 combinations of 4 levels of pCO2 and 4 levels of temperature will be assessed for each participant
Masking: Single (Investigator)
Primary purpose: Basic Science