[Current antibiotic prophylaxis in colorectal surgery]. / Suvremenna antibiotichna profilaktika v kolorektalnata khirurgiia.

Over a one-year period (November 1996 to November 1997), in the Emergency Surgery Clinic perioperative parenteral antibiotic prophylaxis during colorectal operations is performed in a series of 32 patients, admitted on an emergency and deferred urgency basis, or for routine operative treatment. Of them 30 present malignant processes involving colon and rectum, and two--inflammatory diseases. All patients receive single i.v. injections with Cephalothin/Cefazolin at dose 2.0 g and Metronidazole 0.5 g immediately after anesthesia induction. In nine cases additional early treatment is necessitated--within 24 hours after the operative intervention--by administration of the same drug combination 4 times at 6-hour intervals, and in another two prophylaxis is substituted for continuous 5-day treatment using the same therapeutic scheme. In 30 patients the postoperative period runs a course free of noteworthy complications. In two instances there is evidence of operative wound suppuration, and in further two--urinary tract infection development unrelated to the antibiotic prophylaxis applied. The specific features characterizing the application of antibiotic prophylaxis during colorectal surgery are discussed, and appropriate drug therapy schemes are recommended, consistent with worldwide and Bulgarian experience along this line, as well as with the concrete hospital and economical conditions in this country. Special emphasis is laid on two aspects: optimization of the timing of antibiotic agent/agents injection, and reaching peak serum and tissue bactericidal concentrations in the immediate vicinity of the surgical incision; optimization of the duration of antibiotic prophylaxis on the ground of well established indications for the application of antibiotic prophylaxis in colorectal surgery in compliance with the dynamic patterns of intra- and postoperative septic risk. The modest number of patients subjected to updated parenteral perioperative antibiotic prophylaxis does not warrant a definitive interpretation of the data from the comparative clinical and pharmaco-economical analyses performed. Nevertheless, the preliminary results point to the economical expedience of the therapeutic approach suggested.

[The use of metamizole as a risk factor in the occurrence of agranulocytosis]. / Upotrebata na metamizol kato riskov faktor za vuznikvane na agranulotsitoza.

The risk of agranulocytosis following the use of metamizole was studied by the method of controlled cases. All cases of agranulocytosis and their control cases in Sofia for the period 1982-1986 were included in the study. The mean agranulocytosis morbidity for this period was 3.16 cases for one million population for one year. The etiologic fraction was 7.1%. The relative risk of agranulocytosis following the use of metamizole is 1.25, the maximal risk is 0.03 cases for one million persons using metamizole for one year and the maximal lethal risk is 0.007 cases for one million persons using metamizole for one year. The use of metamizole in Bulgaria for the same period was studied, too. The data presented as a number of defined daily doses used by 1000 population for one day show that the use of metamizole in this country is high. A tendency toward an increase of 7.3% per year was found during the investigation. At the same time the agranulocytosis morbidity remained constant during the period of investigation. The results of the study lead to the conclusion that the use of metamizole is not related to a higher risk of agranulocytosis.

[Pharmacokinetics of the cephalosporin antibiotic cefotiam following its intravenous administration to patients after cholecystectomy]. / Farmakokinetika na tsefalosporinoviia antibiotik tsefotiam sled intravenozno vuzvezhdane na bolni sled kholetsistektomiia.

The pharmacokinetic behaviour of cephalosporin antibiotic, second generation after intravenous administration to patients during the early post-operative period was characterized as well as after cholecystectomy. The data suggest a two-compartment distribution with elimination from the central compartment, realized on account of the renal way of clearance. In one of the patients, with one-compartment distribution of the drug, the presence of the theoretical determining factors in "the collapse" of one two-compartment open model to one-compartment is shown, associated with clinical characteristics of that patient.

[Characterization of the pathways of cefotiam elimination by clearance approaches in patients following cholecystectomy]. / Okharakterizirane na putishtata za eliminirane na tsefotiam pri bolni sled kholetsistektomiia posredstvom klirunsovi podkhodi.

The clearance approach was used in the evaluation of the role of renal and biliary excretion in the total elimination of cephothiam from organism of patients after cholecystectomy. Six patients with inserted T-like drain into the choledochus duct and urinary catheter after gall bladder operation received I g cephothiam by stream intravenously during the early postoperative period. The value of renal clearance (= 132.86 +/- 27.35 ml/min) was with one order higher than that of biliary clearance (= 11.54 +/- 9.67 ml/min) and revealed glomerular filtration as the basic mechanism for elimination of cephothiam from the organism of those patients. The value for the sum Clr + Clb = 144.40 ml/min. kre + keb + 1.51 h1-resp. corresponded to the value of the clearance from the central (plasma) compartment, that for kle resp. suggesting that the kidneys and liver were part of that compartment. The high degree of positive correlation between the biliary clearance and biliary flow (r = 0.94, p less than or equal to 0.02) as well as the positive dependence of the biliary excretory rates, biliary excretory rate constants resp X 80, (r = 0.81, r = 0.83 resp) from the biliary flow revealed that the elimination of the drug from the live depends on the volume of the biliary flow. The negative correlation (r = -0.87, p less than 0.05) between the half-life for biliary excretion and the volume of the biliary flow support that presumption.

[Significance of spontaneous and evoked temperature changes in the brain in applying the thermoclearance technic to the determination of cerebral blood flow]. / Znachenie na spontannite i evokiranite temperaturni promeni v mozuka pri izpolzuvane na termoklirunsova tekhnika za opredeliane promenite v mozuchniia kruven potok.

The authors carried out studies on cats under urethane narcosis and found that the presence of spontaneous temperature changes in two neighbouring regions of the cerebral cortex, were discovered at a distance of 5 mm from each other in a parallel course. After administration of pharmacological agents such as papaverine, nivaline, etc. in the region of the cerebral cortex there were quick transitory temperature changes as in the two neighbouring regions of the cortex these changes had one-way course, but not a parallel one. This caused the occurrence of changes in the temperature difference between them, which was recorded by switching of the differential amplifier. These changes could be indicated as "zero reaction", having in mind the essence of the thermoclearance methods by means of which additional source of heat was introduced in one of the two regions. The real changes in the blood flow of the brain under the influence of the administered pharmacological agent represented the difference between the recorded and the so called zero reaction. The established facts oblige to take into consideration a possible presence of "zero reaction" during usage of thermoclearance method for determination of blood flow in other organs as well.

[K+, H+ and Ca++ concentrations in the perivascular fluid as a factor in the regulation of the lumina of the vessels of the pia mater]. / Kontsentratsiite na K+, H+ i Ca++ v perivaskularnata technost kato faktor v regulatsiiata na prosveta na sudovete na pia mater

The author separed the vascular vessels of pia mater with a size of 20-150 microns in cats under penthobarbital narcosis. The perivascular area of the vessels was perfused by an artificial fluid with varying concentrations of potassium, hydrogen and calcium. The local contraction of the smooth vascular musculature was induced by stimulation with rectangular impulses by means of electrodes introduced by micromanipulators in immediate vicinity of a vessel. The changes were recorded by means of microphotographic images of the vessels. It was established that the contraction of the vessels was observed when there was a lack of potassium or at concentration of 100 meq/l. There was no change at 2,5-3,0 and at 50-60 meq/l of potassium. Vasodilatation was found at 10-20 meq/l. Electrical stimulation caused stronger contraction of the vessel, when there was a lack of potassium in comparison with the norm (2,7 meq/l). The increase of potassium caused a reduction of the dimensions of the effect due to electrical stimulation. The vascular dilatation, induced by 10-20 meq/l of potassium was not affected by the increase of the calcium concentration (6-9 meq/l) in artificial fluid. The vasodilatation, induced by an increase of hydrogen, was abolished by raising the concentration of calcium in the artificial fluid. The obtained results were discussed.