Computation of respiratory heat exchanges.

Two sets of equations have been proposed to estimate the convective or sensible (WCV) and the evaporative or insensible (WEV) respiratory heat exchanges. They are applicable both at sea-level barometric pressure with air breathing (SLA) and in hypo- or hyperbaria in both air (HA) and artificial (HAA) atmospheres. The only environmental parameters required are in SLA: the temperature (TI) and the partial pressure of water vapor of the inspired air (PIH2O); in HA: TI, PIH2O, and the actual barometric pressure (PB); and in HAA: IT, PIH2O, PB, the volumetric mass (rho mix), and the specific heat (cp mix) of the breathed gas mixture. When no physiological data are available the results are expressed in energy units per liter of pulmonary ventilation (WCV/V and WEV/V) in J X dm-3 BTPS. If the ventilation value (V) is known the results are obtained in units of power (W).