[Osmotic colloidal pressure: measurement and clinical importance].

Knowledge of osmotic pressure has long existed and its practical use in the treatment of patients under intensive care has been widely developed over the past few years following the introduction of simple electronic osmometers. It is related more to plasma albumin than to globulins. It varies in relation with a certain number of physiological factors and in different pathological circumstances. The value of OP and above all of the difference OP--PCP in the prevention, diagnosis, treatment and prognosis of pulmonary oedema has been clearly demonstrated in several recent studies. Its value in relation to total serum proteins is that it takes into account any possible dysproteinaemia and that it is directly expressed in units of pressure which makes possible the calculation of the OP--PCP difference which represents the difference between the only OP--PCP difference which represents the difference between the only two intravascular forces which participate in fluid exchanges at the level of the pulmonary capillary.