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Biomedical subjects

A Todorov

Publications and source records attributed to A Todorov.

At least 19 recordsLinked to original sources
PubMed1997

Convection versus conduction cooling for induction of mild hypothermia during neurovascular procedures in adults.

Hypothermia for cerebral protection is usually achieved by administration of intravenous fluids at room temperature, cooling ambient air, ice packs, and a temperature-adjustable circulating water mattress. We compared cooling by conduction by using a water mattress to cool by convection by using a forced-air cooling device. Twenty patients were prospectively randomized to two groups: 10 patients cooled by convection (CC) and 10 patients cooled by traditional methods (TC). Two patients in the CC group were withdrawn from the study and excluded from the analysis; one patient for failure to cool despite the use of both techniques, and the other for the abrupt onset of arrhythmias and myocardial depression during hypothermia. Temperature was measured at the tympanic membrane, pulmonary artery, and esophageal probe sites and recorded every 15 min. The time required to reach the target temperature range of 33-34 degrees C was recorded. We found no differences in the temperatures measured at the three sites during cooling and rewarming. Baseline temperatures recorded from the pulmonary artery catheter before beginning "active cooling" were similar in both groups (TC, 35.0 +/- 0.2 degrees C vs. CC, 35.3 +/- 0.1 degrees C). We found no difference in the time to target temperature between TC and CC (TC, 178 +/- 25 min vs. CC, 142 +/- 21 min). One patient had some arrhythmias on cooling in the convective group, but her preoperative condition may have been responsible. In conclusion, cooling by convection appears to be a safe alternative to conduction cooling.

Adult↗
PubMed1996

Combining extremely concordant sibpairs with extremely discordant sibpairs provides a cost effective way to linkage analysis of quantitative trait loci.

Extremely discordant (ED) sibpairs have been shown to be very powerful for linkage analysis of human quantitative traits [Risch and Zhang (1995) Science 268: 1584-1589]. In many cases, the extremely concordant (EC) sibpairs collected in the process of screening for ED sibpairs carry valuable information for linkage. Therefore, it seems justifiable to investigate the advantages of genotyping and to include them with the ED sibpairs for linkage analysis. Herein we explore the distributions of EC as well as ED sibpairs under various genetic models and provide a basis for combining both types of sibpairs. A simple statistic testing means of genes shared identical by descent (IBD) in applied to combine both types of EC sibpairs (high-high and low-low) with the ED pairs. We show that when a decent number of EC pairs is added to the ED sample for analysis, the power is much enhanced, making it especially desirable when the number of available ED pairs is small. We show at the same time that combining EC pairs with ED pairs is more cost effective than pursuing ED sibpairs alone.

Costs and Cost Analysis↗
PubMed1996

Jugular bulb temperature: comparison with brain surface and core temperatures in neurosurgical patients during mild hypothermia.

Blood temperature at the jugular bulb was monitored in 10 patients undergoing neurovascular procedures that used induced mild hypothermia, and its correlation with surface brain, core, and peripheral temperatures was determined. The study was motivated by the difficulty encountered in directly measuring global brain temperature and the poor correlations between various core and peripheral sites temperatures and brain temperature, particularly during deep hypothermia. Although not statistically significant, previous studies have suggested a trend toward higher brain temperatures. Temperatures from the jugular bulb (collected using a No. 5 French Swan-Ganz catheter) as well as from subdural, pulmonary artery, esophagus, tympanic membrane, and bladder sites were analyzed during three surgical conditions: prior to incision, with the dura open, and after closure of the dura. No complications related to placement of the jugular bulb catheter, induced hypothermia, or temperature monitoring were seen. The authors found that jugular bulb temperature was similar to pulmonary artery and esophageal temperatures; although prior to incision it tended to be higher than that found at the pulmonary artery, most commonly by 0.2 degrees C. Surface brain temperature was cooler than all other temperatures (p < 0.05), except that of the tympanic membrane, and was particularly sensitive to environmental variations. Finally, as has been shown by others, bladder temperature lagged substantially behind core temperatures particularly during rapid cooling and rewarming of the patient. In summary, monitoring of jugular bulb temperature is a feasible technique, and temperatures measured in the jugular bulb are similar to core temperatures.

Adult↗
PubMed1990

[Subphrenic abscess and suppurative pericarditis as complications in children with perforated appendicitis].

The combination of subphrenic abscess with purulent pericarditis is a rare postoperative complication of perforated appendicitis in children, with severe clinical course, difficult to diagnose and high case fatality rate. A 7-year-old child with this complication, successfully diagnosed and treated is reported. The importance of complex therapy--surgical and intensive and collaboration between pediatric surgeons, anesthesiologists, cardiac surgeons and cardiologists for the favourable outcome is emphasized.

Appendicitis↗
PubMed1989

[Functional disorders of cardiac pacemakers--their diagnosis and treatment].

Implantation of artificial pacemaker has proven invaluable in the treatment of patients with heart block and other arrhythmias. It has been found that, however seldom, this device may function inadequately after implantation. This malfunction is secondary to alteration in the previously assigned rate, to irregular pacing and failure of sensing, impaired capture or depolarization and/or various combinations of these events. The welfare of patients with pacemaker depends on the adequate investigation and interpretation of the malfunction and its proper management. The numerous signs of pacemaker malfunction are associated with changes in the output of impulses and inadequate pacing. It is believed that in the future the developing technology will provide more refined pacemaker device, and the incidence of pacemaker malfunction with fall to a reasonable limit.

Arrhythmias, Cardiac↗
PubMed1982

[Morphometric and histophysical studies of the limb skeleton of rats in hypokinesia].

Studied were the bones of the limbs of 20 male rats of the Wistar line divided into 2 groups--one immobilized and one control. The latter was raised under the normal conditions of a vivarium, and the test group of 60-day-old rats was kept in individual cells for physiologic immobilization. The experiment lasted for a total of 390 day, i.e., at the time of killing and sampling the animals were at the age of 450 days. Each part of the limbs was measured severalfold at several sites by means of a slide-gauge and the data were processed statistically and via dispersion analyses. Besides, the structure of the bone tissue was investigated in histologic preparations, determining the density of the osteocytes. Measured was also the microhardness after Wikers of the bones of the two groups of animals, using a metallographic microhardmeter. It was established that all bones of the fore- and the hindlimb were shorter and in general smaller under the effect of hypokinesia. Immobilization was shown to affect chiefly the proximal bones of the limb skeleton. The growth of the bones decreased in hypokinesia to the detriment not so much of the cell elements than of the intercellular matter of the bone tissue. The microhardness of the bones of the immobilized rats was lower than that of the control ones.

Animals↗