Inform: conceptual modelling of intensive care information systems.

Intensive care of a patient requires heavy monitoring and versatile therapeutic actions. These produce a huge amount of patient information. A problem exists in managing this data and other information from all supporting activities creating a need for an automated information management system. To have a sound basis for future automated information systems in intensive care unit (ICU), a conceptual model is created to cover both the clinical and other activities of the ICU. The conceptual model consists of data flow diagrams and entity-relationship diagrams with underlying common data dictionary. A modern CASE tool is utilized to build the model. The work forms a part of AIM-INFORM project, which has a purpose to develop information management and decision support systems for high dependency environment.

Effects of various ventilation modes on immunocompetence in surgical patients.

The effects of controlled mechanical ventilation with PEEP (CMV), and spontaneous ventilation with continuous positive airway pressure (CPAP), CPAP with high frequency ventilation (CPAP-HFV) and spontaneous respiration without CPAP (SV) on immunocompetence were compared in open-heart surgery patients undergoing the weaning phase. T-lymphocyte and T-helper cell ratios decreased during CPAP (P less than 0.01) and SV (P less than 0.05). PWM-induced lymphocyte proliferative responses were decreased during CPAP-HFV (P less than 0.05), CPAP and SV (P less than 0.01) in whole blood and separated lymphocyte cultures compared to values during CMV. Con A-induced responses were also depressed during SV in whole blood cultures (P less than 0.01). When the synthesis and secretion of immunoglobulins were studied, only IgM production showed a decrease in PWM-stimulated cultures during SV (P less than 0.05). In spite of an increase in the cardiac index in the three spontaneous ventilation modes compared to CMV, a slight decrease instead of an immediate improvement was seen in immune responses on weaning to spontaneous ventilation modes.

Continuous positive airway pressure with and without high-frequency ventilation: hemodynamics, oxygenation, and endocrine response.

After 18 h of mechanical ventilation following open heart surgery, central hemodynamics, systemic oxygen delivery (DO2), and oxygen consumption were assessed in ten consecutive patients receiving continuous positive airway pressure (CPAP) therapy. Plasma vasopressin, norepinephrine, and epinephrine levels were analyzed. While maintaining the mean airway pressure, two CPAP methods were studied: a demand CPAP with continuous flow without (CPAP) and one with high-frequency ventilation (CPAP-HFV). The frequency used during CPAP-HFV was 300 cycle/min. The spontaneous ventilatory rate was found to be equal during CPAP and CPAP-HFV. The cardiac and stroke volume indices were slightly higher (p less than .05) during CPAP-HFV, which accounted for the finding that DO2 was also slightly higher (p less than .05) during CPAP-HFV. The epinephrine and norepinephrine levels did not differ, whereas the vasopressin level was somewhat higher during CPAP-HFV, which might indicate a higher level of vigilance. It is concluded that cardiac output was slightly higher during CPAP-HFV compared to that during CPAP. This may be due to an effect of the oscillations on circulation or to differences in the level of vigilance.

Pulmonary uptake of PGE2 is inhibited by dipyridamole in rat isolated lungs.

The metabolism of prostaglandin E2 (PGE2) is decreased by dipyridamole (20 microM) in rat isolated perfused lungs. The inhibition of the metabolism is reversible as the decreased metabolism returned to the control level when pulmonary infusion of dipyridamole was abolished. After pulmonary injection of 14C-PGE2 (10 nmol) the radioactivity appeared more rapidly in the effluent when dipyridamole was infused into pulmonary circulation. Dipyridamole in vitro did not change the activity of 15-hydroxyprostaglandin dehydrogenase (15-OH-PGDH) in the 100,000 x g supernatant fraction of homogenized lungs. Thus, the decreased metabolism seems to be due to the inhibition of the uptake of PGE2 into the lungs. When the rats were pretreated with dipyridamole in drinking water for one week the activity of 15-OH-PGDH in the 100,000 x g supernatant fraction of the lungs was not changed significantly.

Dietary cholesterol-induced changes of xenobiotic metabolism in liver. I. Influence of xenobiotic administration on hepatic membrane structure.

We have studied the effects of dietary lipids on the structure and function of hepatic endoplasmic reticulum by feeding rats either with a 2% cholesterol or cholesterol-free diet. Rats were further administered either phenobarbitone, carbon tetrachloride, or both in combination to reveal possible differences in the response of the microsomal membranes to xenobiotics. Cholesterol feeding increased the membrane cholesterol contents and also carbon tetrachloride increased microsomal cholesterol contents in those rats fed a cholesterol-free diet. Also the microsomal phospholipid contents were higher in those rats fed 2% cholesterol diet than in those fed cholesterol-free diet and in the 2% cholesterol group also phenobarbitone increased the phospholipid contents. In addition, there were changes in the phospholipid-fatty acid proportions between rats fed 2% cholesterol and cholesterol-free diets. When 1,8-ANS was used as a fluorescence probe, phenobarbitone increased the fluorescence in both the dietary groups, while carbon tetrachloride decreased it; less change was present using PNA as a substrate. When Scatchard plots were constructed phenobarbitone changed the turning point more in the cholesterol-free group than in the 2% cholesterol group, while reversed orders of changes were found with carbon tetrachloride. The results demonstrated that dietary cholesterol has profound effects on the structure of microsomal membranes far beyond changes in their cholesterol content. The membrane fluidity also changes owing to alterations in the phospholipid contents and in their fatty acid composition.

Dietary cholesterol-induced changes of xenobiotic metabolism in liver. II. Effects of phenobarbitone and carbon tetrachloride on activities of drug-metabolizing enzymes.

The influence of dietary cholesterol on drug metabolism was studied by feeding rats either a cholesterol-free or a high (2%) cholesterol diet for 4 weeks from weanling onward and giving phenobarbitone (Pb) and/or carbon tetrachloride (CCl4) thereafter. Pb was given in drinking water for 7 days at a dosage of 100 mg/kg and CCl4, at a dosage of 1.5 mg/kg SC 6 days before assays of drug-metabolizing enzymes. The cytochrome P-450 concentration was 2-fold in rats fed the 2% cholesterol diet in comparison with those fed the cholesterol-free diet. Only a weak induction by Pb was found in the cholesterol-free group. Only slight differences due to the cholesterol diets or due to the administration of xenobiotics were found in the NADPH cytochrome c reductase activity. The PPO hydroxylase activity was 2-fold in the livers of rats fed the 2% cholesterol diet in comparison with those fed the cholesterol-free diet. In the ethoxyresorufin deethylase activity, differences between diets were present first after the administration of xenobiotics. No change in the hepatic aryl hydrocarbon hydroxylase activity was found due to changes in the cholesterol content of the diets. The ethoxycoumarin O-deethylase activity was 2-fold in the livers of rats fed 2% cholesterol diet from those fed the cholesterol-free diet. The inducibility of ethoxycoumarin O-deethylase was equal, regardless of which diet was used. The hepatic epoxide hydrolase activity of rats fed 2% cholesterol was 3-fold in comparison with the cholesterol-free group. The inducibility by Pb was higher in the livers of the cholesterol-free (3.3-fold) than 2% cholesterol-fed rats (2.4-fold). The hepatic UDP-glucuronosyl-transferase activity was 1.5-fold in 2% cholesterol-fed rats in comparison with rats fed the cholesterol-free diet. The inducibility by CCL4 was found only in rats fed the cholesterol-free diet. The results suggest that dietary cholesterol modifies the enzyme activities in the liver and modifies their response to enzyme inducers.