[Therapeutic hypothermia and acid-base management].

Moderate hypothermia is being increasingly advocated for acute neurological clinical situations. In case of proved clinical success, however, it is relatively time consuming and requires personal and structural resources. In addition, profound knowledge and a sound understanding of the physiology of hypothermia are necessary prerequisites. In particular, the variety of untoward effects, which increase with decreasing temperature, underline the need for specific diagnostic and therapeutic skills. A further challenge is associated with the adaptation of the parameters of homoeostasis to a basically altered temperature. Among these, management of acid-base balance is a managerial cornerstone. In principle, two different regimens may be used, i.e. the pH-stat and the alpha-stat regimes. Applying pH-stat during hypothermia means keeping the pH constant, whereas the H(+)/OH(-) quotient is held constant when relying on the alpha-stat regime. Because of the lack of prospective clinical data any comparative evaluation of the two alternatives actually remains a matter of speculation. However, experimental data as well as physiological considerations may support an illness-oriented differentiated approach (e.g. increased cerebral pressure vs. cardiac arrest vs. stroke). Prospective studies are required to allow an evidence-based and substantiated clinical decision regarding the management of pCO(2) and pH during therapeutic hypothermia.