Projects / Programmes source: ARIS

Učinek narkoze z internimi plini na termoregulacijo pri človeku (Slovene)

Research activity

Code Science Field Subfield
3.08.00  Medical sciences  Public health (occupational safety)   

Code Science Field
B470  Biomedical sciences  Physiology 
B690  Biomedical sciences  Occupational health, industrial medicine 
hyperbaric physiology, inert gas narcosis, hypothermia, behavioural thermoregulation, autonomic thermoregulation, nitrogen narcosis, nitrous oxide narcosis, pressure reversal effects
Evaluation (rules)
source: COBISS
Researchers (2)
no. Code Name and surname Research area Role Period No. of publicationsNo. of publications
1.  11537  PhD Polonca Jaki Mekjavič  Medical sciences  Researcher  1999 - 2001 
2.  14676  PhD Igor Mekjavić  Cardiovascular system  Head  2000 - 2001 
Organisations (1)
no. Code Research organisation City Registration number No. of publicationsNo. of publications
1.  0312  University Medical Centre Ljubljana  Ljubljana  5057272000  125 
Hypothermia has been implicated as a major cause in diving fatalities. Based on the evidence that narcosis attenuates autonomic and behavioural thermoregulatoy responses, it is likely that compressed air divers are predisposed to hypothermia during cold water diving. Although evidence suggests that a volatile narcotic gas such as nitrous oxide affects behavioural, but not autonomic responses, in a dose dependent manner, vhether a similar effect is exerted by hyperbaric nitrogen remains unresolved. The proposed research programme will investigate the interaction of temperature, narcosis and pressure on human temperature regulation. It is hypothesized that with progressive cooling of deep body temperature, the efect of narcosis is potentiated. Furthermore, based on evidence of a pressure reversal effect of narcosis, we will examine whether this phenomenom is significant in modulating thermoregulatory responses in humans at pressures considered the imit of compressed air diving. Homeothermia in humans is achieved by the unimpaired activity of both behavioural and autonomic thermoregulatory responses. To date, studies have reported an impairment in the subjective perception of temperature during exposure to narcotic gases. In addition to examining the effect of the interacting influences of temperature, arcosis and presure on autonomic thermoregulatory responses, experiments will be performed to elucidate the magnitude of the effect of this interaction on behavioural thermoregulatory responses. Experiments will be performed on human subjects, by rendering them hypothermic with cold water immersio in a hyperbaric chamber. The influences of temperature, pressure and narcosis will be examined by varying the concentrations of PN2, PHe and PN20 in the breathing mixture, during progressive cooling of subjects towards nild hypothermic levels. In this manner, the proposed studies will elucidate the combined, and individual effects of narcosis and hydrostatic pressure on thermoregulatory responses. The results of this research programme will enhance our understanding of the mechanisms by which hypothermia is potentiated in compressed air diving. It will increase awareness of the potentially hazardous effects of deep air diving and demonstrate the need to limit air diving to depths, where the level of narcosis does not significantly affect behavioural and autonomic responses.
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