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Biomedical subjects

K Geiger

Publications and source records attributed to K Geiger.

At least 91 records · Page 5Linked to original sources
PubMed1993

Exogenous or endogenous reservoirs of nosocomial Pseudomonas aeruginosa and Staphylococcus aureus infections in a surgical intensive care unit.

OBJECTIVE: A 4 month prospective study was performed to assess the incidence and routes of endogenous or exogenous colonization and nosocomial infection caused by Staphylococcus aureus and Pseudomonas aeruginosa in surgical critically ill patients. DESIGN: A total of 4634 specimens were obtained. Patient's nasal, scalp, and rectal swabs as well as tracheal secretion (TS) were cultured every second day beginning on the day of admission. Nasal swabs and hand cultures of the personnel as well as cultures from gowns were also taken. All isolates of S. aureus were phage typed and 116 of these isolates were also plasmid typed. P. aeruginosa isolates were sero- and pyocin typed. Resistance patterns were determined in all isolates. SETTING: The study was carried out in the surgical intensive care unit (SICU) of an teaching hospital. PATIENTS: During the study period each patient (a total of 153 patients) admitted to the SICU entered the study. RESULTS: P. aeruginosa and S. aureus colonisation rate on admission were 5% and 36.5% respectively. Only 10 patients (6.5%) were colonized with P. aeruginosa during hospitalization, and only 7 patients (4.5%) acquired S. aureus in the surgical intensive care unit (SICU). The most common primary colonisation site of P. aeruginosa was the rectum, whereas S. aureus was predominantly found in nasal cultures. Horizontal transmission of S. aureus occurred in only 2 patients. CONCLUSION: The study suggests that colonisation with P. aeruginosa and S. aureus occurs from endogenous rather than from exogenous sources and that the endogenous acquisition of both bacteria play a more important role in development of nosocomial infections than the exogenous route of transmission.

Cross Infection↗
PubMed1993

Enhancement of in vitro bactericidal activity of neutrophils from trauma patients in the presence of granulocyte colony-stimulating factor.

In order to determine whether granulocyte colony-stimulating factor (G-CSF) can enhance the bactericidal activity of polymorphonuclear leukocytes (PMNL) in trauma patients, PMNL obtained from severely injured patients one or two days after trauma were incubated with G-CSF and Staphylococcus aureus for different periods of time. G-CSF at a concentration of 6000 units/ml significantly improved the antibacterial activity of PMNL in trauma patients (n = 10) and healthy volunteers (n = 12) during the incubation period of 180 min. No difference in the bactericidal function of PMNL could be found between severely injured patients and healthy donors.

Adult↗
PubMed1993

[Chronic lipogranuloma (paraffin granuloma) of the eyelids and orbits after endonasal paranasal sinus operation].

During the last five years 10 patients received surgical treatment in our eye clinic for tumours of the eyelids and the orbit that had developed after endonasal sinus surgery. In most patients the first signs of lid or orbital involvement had occurred 4 weeks after ENT surgery and after a unilateral or bilateral postoperative haematoma had subsided. The histological examination of the surgical specimens showed chronic sclerosing lipogranuloma containing large vacuoles surrounded by epithelioid and giant cells, typical of a so-called paraffin granuloma. MR-spectroscopy detected high concentrations of paraffin in the specimens of 3 patients. Since paraffin is a constituent of many ointments, we assume that the granulomatous reaction was elicited by the ointment tampons routinely applied to the wound area following sinus surgery. The bleeding acted as a vehicle to distribute the paraffin into the surrounding tissues.

Adult↗
PubMed1993

[Inhaled nitric monoxide. Application and continuous measurement of concentration].

Inhaled nitric oxide (NO) is a selective pulmonary vasodilator that may be useful in the treatment of patients with severe pulmonary hypertension. We describe a delivery system of inhaled NO that allows safe application and continuous measurement of the inspired NO concentration during mechanical ventilation. From a gas cylinder containing NO in N2 (600 ppm NO), an adjustable amount of gas is introduced into the inspiratory side of the tubing system via a pressure reduction valve, a magnetic valve, and a special injection nozzle. The NO concentration is diluted to the desired value by the tidal volume. The magnetic valve is connected to the ventilator and opens at the beginning of each inspiration and closes after a predetermined time. The gas volume is proportional to the pressure at the magnetic valve and the opening time. To monitor the inspiratory NO concentration, a specimen of gas is taken from an angle-connector and passed over an electrochemical sensor. The second nozzle of the sensor is connected to a water seal, which is adjusted to the positive end-expiratory pressure level of the ventilator to insure that the gas flow over the sensor is limited to inspiration.

Administration, Inhalation↗
PubMed1992

Prolongation of hospital stay and extra costs due to ventilator-associated pneumonia in an intensive care unit.

A prospective cohort study was performed to determine the prolongation of stay and the extra costs incurred due to the occurrence of ventilator-associated pneumonia in intensive care unit patients. Over a 16-month period a sample of 270 consecutive adult patients from a large university anesthesiological intensive care unit requiring ventilation therapy for more than 24 hours was analyzed. A matching procedure using multiple control patients without pneumonia per infected patient (= case) was employed. Of 78 cases 21 (26.9%) died and were excluded from the matching procedure as well as 23 (29.5%) for whom suitable controls could not be found. The maximum number of controls per case was five. The mean added stay was calculated to be 10.13 days and the extra costs attributable to the prolongation of stay were 14,253 German Marks (US$8,800) per patient, demonstrating considerable added stay and costs due to ventilator-associated pneumonia acquired during intensive care. However, it should be taken into account that the calculations for excess stay and costs are based on a subset of rather ill patients and thus cannot generally apply to all ventilated patients and that cases were excluded which could not be matched.

Adult↗
PubMed1992

Platelet-activating factor primes human eosinophil generation of superoxide.

Platelet-activating factor (PAF) is a potent inflammatory mediator that can cause airway obstruction and hyperresponsiveness; these processes are also associated with pulmonary eosinophilia, suggesting a link between these two events. Thus, PAF's interaction with eosinophils may provide a mechanism for airway damage. However, direct in vitro activation of eosinophils by PAF requires concentrations that are likely higher than those achieved in vivo. As a result, we investigated whether lower, more physiologic concentrations of PAF could prime eosinophils for subsequent activation to another receptor-stimulated factor, in this case formylmethionylleucylphenylalanine (FMLP). To test this hypothesis, eosinophils were preincubated (1 and 15 min) with low concentrations of PAF (1 x 10(-8) and 1 x 10(-10) M); this exposure to PAF resulted in enhanced generation of superoxide anion to FMLP stimulation. Moreover, similar concentrations of PAF decreased eosinophil density and increased expression of cell surface CR3 receptors. Finally, low, nonactivating concentrations of PAF (1 x 10(-10) to 1 x 10(-8) M) caused transient increases in eosinophil cytosolic free Ca2+ concentrations. Collectively, these responses are consistent with the hypothesis that short-term exposure to low concentrations of PAF primes eosinophils to cause an enhanced inflammatory response upon subsequent activation to another receptor agonist. The consequences of this PAF-associated phenomenon can produce an enhanced inflammatory response and airway injury.

Adult↗
PubMed1992

Splanchnic hemodynamics and oxygen supply during acute normovolemic hemodilution alone and with isoflurane-induced hypotension in the anesthetized pig.

Safety of combined hemodilution and isoflurane-induced hypotension was assessed by studying their effects on splanchnic hemodynamics and oxygenation in nine anesthetized (ketamine/flunitrazepam) pigs. Acute normovolemic hemodilution (decrease in hematocrit from 29% to 15%) with 6% hydroxyethyl starch decreased (P < 0.05) O2 delivery despite increases in cardiac output and all splanchnic flows, as measured by electromagnetic flow probes. Superimposed isoflurane (1.45% end-tidal concentrations) caused marked decreases in arterial blood pressure, cardiac output, and splanchnic flows. Oxygen uptake of the liver became O2 supply dependent. A liver surface PO2 histogram (Clark-type electrode) showed 38% of PO2 values between 0 and 5 mm Hg. Hepatic lactate uptake decreased by 75%. These data suggest that depression of cardiovascular function during reduced O2-carrying capacity adversely affects hepatic perfusion, oxygenation, and function. Combined hemodilution and isoflurane-induced hypotension may not be appropriate in patients.

Anesthesia↗
PubMed1991

Incidence of pneumonia in mechanically ventilated patients treated with sucralfate or cimetidine as prophylaxis for stress bleeding: bacterial colonization of the stomach.

Retrograde colonization of the oropharynx from the stomach by microaspiration of gastric fluid is a recently recognized phenomenon associated with increased gastric pH that may result in pneumonia during ventilation therapy. In a prospective study we investigated 104 mechanically ventilated patients in the intensive care unit who were receiving sucralfate (n = 49) or cimetidine (n = 55) for stress ulcer prophylaxis. The incidence of pneumonia was 45.5% (25 patients) in the cimetidine group and 26.5% (13 patients) in the sucralfate group (95% confidence interval 0.98 to 6.97; odds ratio 2.61; p = 0.0549). Mortality rates were 18.4% (9 patients) in the sucralfate group versus 25.5% (14 patients) in the cimetidine group (p = 0.48). The mean pH values of gastric aspirates were significantly lower in patients treated with sucralfate than in patients receiving cimetidine (p = 0.044). The number of colony-forming units of Enterobacteriaceae in gastric aspirates was also significantly lower in the sucralfate group (p = 0.0037).

Adult↗
PubMed1991

[Prolongation of hospital stay by nosocomial pneumonia and wound infection].

From June 1988 to September 1989, a prospective survey comprising a total of 1183 patients in a university hospital was carried out to ascertain the additional length of stay in intensive care units because of nosocomial pneumonia associated with artificial ventilation (418 patients, 296 men, 122 women, mean age 48.8 +/- 21 years, ventilated for more than 24 h) or by postoperative wound infections (765 patients, 501 men, 264 women, mean age 60 +/- 11 years, after operations on the large bowel, heart or biliary tract). Each patient with a nosocomial infection was matched against a variable number of control patients (for cases of pneumonia a maximum of 6, for wound infections a maximum of 10) without nosocomial infection. Pneumonia developed in 100 (23.9%) of artificially ventilated patients, and 46 of these patients together with 101 controls were entered into the matching procedure. 24 patients with pneumonia had to be excluded from analysis because no controls could be found for them, and also 30 patients who died while in the intensive care unit. 49 (6.4%) of the surgical patients contracted postoperative wound infections. 43 of them, together with 210 controls, were entered into the matching procedure. Among patients with pneumonia the average additional duration of stay was 11.5 days, and among patients with post-operative wound infections it was 13.9 days. The results confirm that nosocomial infections contribute substantially to prolongation of hospital stay and hence to the costs.

Adult↗
PubMed1991

Effects of acute normovolemic hemodilution on splanchnic oxygenation and on hepatic histology and metabolism in anesthetized pigs.

Perioperative hemodilution (HD) has become an accepted means of reducing transfusion requirements. Therefore, the effects of limited (decrease in hematocrit [Hct] from 30 to 20%, "HD1") and severe (decrease in Hct from 20 to 14%, "HD2") acute normovolemic HD with 6% hydroxyethyl starch on splanchnic blood flows (electromagnetic flow probes), O2 uptakes and deliveries, surface O2 tensions (PO2) (Clark-type electrode), hepatic metabolism (organic acids), and hepatic histology (liver biopsies) were studied in nine pigs anesthetized and paralyzed with ketamine/flunitrazepam and pancuronium. HD1 caused significant (P less than 0.05) increases in cardiac output and all splanchnic flows. Only hepatic arterial blood flow increased twice as much as did cardiac output. Except for hepatic arterial O2 delivery, all splanchnic O2 deliveries decreased. Splanchnic O2 extractions increased, and O2 uptakes remained unchanged. There were no changes in mean surface PO2 values or in surface PO2 histograms of liver and small intestine; in portal or hepatic venous pH; and in hepatic uptake of pyruvate and lactate. In contrast, during HD2 (despite further increases in flows and O2 extractions) portal and hepatic venous pH decreased; mean surface PO2 of liver and small intestine decreased; and the liver surface PO2 histogram showed broadening and a shift to the left. However, hepatic uptake of lactate and pyruvate, and splanchnic O2 uptake remained unchanged, and histologic examination did not reveal significant cell injury. These data indicate that in this experimental model limited acute normovolemic HD was well tolerated by the splanchnic organs. After severe HD, gross liver function remained intact, but there was evidence that compensatory mechanisms (increases in flow and O2 extractions) were no longer fully able to counteract the decrease in splanchnic O2 delivery.

Anesthesia↗
PubMed1991

[The effect of 6% (40/0.5) hydroxyethyl starch and Ringer's lactate on blood coagulation, laboratory parameters and circulation during peridural anesthesia].

We investigated the effects of 6% hydroxyethyl starch (HES 40/0.5) and lactated Ringer solution (LRS) on blood coagulation tests and laboratory parameters during epidural anesthesia. Additionally, the efficacy of this prophylactic intravenous fluid supply in preventing sympathetic blockade induced hypotension was studied. METHODS. A single shot lumbar epidural block was given to 55 patients using 14-18 ml of bupivacaine 0.75%. The patients were randomized to receive either 1000 ml 6% HES 40/0.5 or 1000 ml LRS starting 5 min before the epidural blockade was set. The first 500 ml was infused during a 15-min period and the remaining 500 ml solution during the next 30 min. Cardiovascular parameters were recorded and blood samples were taken 30, 60, 120 and 240 min after the start of the infusion. RESULTS. No significant differences were found in the cardiovascular parameters, although in patients with a cranial spread of epidural blockade above T 10, patients who received LRS showed more episodes of severe hypotension. Serum osmolarity, potassium and sodium remained constant throughout the observation period. HES 40/0.5 caused a significantly greater hemodiluting effect than LRS, which was evident in more pronounced temporary decreases in serum protein concentration, hemoglobin concentration, hematocrit, fibrinogen and platelets. In coagulation parameters LRS caused no changes of PTT and Quick, whereas HES 40/0.5% led to a significant prolongation of PTT and a decrease in Quick. CONCLUSION. Fluid supply with either LRS or 6% HES 40/0.5 cannot prevent the epidural blockade induced hypotension entirely. In epidural anesthesia with spread of blockade above T 10, 6% HES 40/0.5 is superior to LRS in the prevention of severe hypotension. The temporary increase in plasma volume after infusion of 6% HES 40/0.5 results in a greater hemodilution with a concomitant decrease of blood viscosity and improved microcirculation flow. These might be of interest in prevention of thromboembolic complications. The specific effects of the two solutions were also determinable during epidural blockade.

Adult↗
PubMed1991

[Atrophy of the ganglion cells reduces pattern ERG not only in fine but also in coarse test patterns].

The pattern electroretinogram (PERG) is thought to be generated by the retinal ganglion cells. For coarse patterns, however, it has been suggested that the PERG is due to nonlinear summation of luminance responses. To test this hypothesis, we recorded the PERG in 8 patients with unilateral complete optic atrophy due to trauma or advanced glaucoma. Stimuli were phase-reversing checkerboards (7.8/s) with checks of 0.8 degrees and 15 degrees in size and with flashes. Retinal stimulation subtended 26 degrees x 34 degrees. In all 8 subjects, the PERG was greatly diminished using a check size of 0.8 degrees. With a check size of 15 degrees, the PERG was similarly diminished, while the flash responses were not reduced. Any overall luminance component of the stimulus, e.g., incomplete balance of light and dark areas, evoked strong luminance responses both in normal eyes and in eyes with optic nerve atrophy. Thus, intact ganglion cells seem to be necessary for a normal PERG regardless of the coarseness of the pattern. It is possible that different mechanisms (variable ganglion cell classes) contribute to the PERG response with different check sizes. Earlier reports, contradictory to these findings, are discussed. If the PERG reflects ganglion cell function even for large check sizes, stimulation of the ganglion cells with less optical degradation would be possible, enlarging its range of applications.

Attention↗