Search PubMed⌕ Search

Biomedical subjects

G Hempelmann

Publications and source records attributed to G Hempelmann.

At least 127 records · Page 7Linked to original sources
PubMed1999

Cerebral blood flow velocity during isovolemic hemodilution and subsequent autologous blood retransfusion.

PURPOSE: To quantify the influence of hematocrit on cerebral blood flow velocity (CBFV) in healthy volunteers undergoing acute isovolemic hemodilution (HD) with hydroxyethyl starch 10% (HES) and subsequent autologous whole blood retransfusion (RT). METHODS: In 11 volunteers 20 ml x kg(-1) blood was withdrawn over 30 min and simultaneously replaced with HES 10%. Thirty min later, RT was started at a constant rate over 30 min. Recorded parameters included: CBFV pulsatility-index (PI) and resistance-index (RI) of the middle cerebral artery (MCA). Blood pressure (BP), heart rate (HR), hemoglobin (Hb), hematocrit (Hc) peripheral O2-saturation (SpO2), P(ET)CO2, arterial oxygen content (CaO2) and cerebral arterial O2-transport (C(E)-DO2= CaO2 x Vm-MCA) were monitored. RESULTS: An average of 1570 total blood was withdrawn which resulted in a decrease in Hb from 14.5 mg x dl(-1) to 10.3 mg x dl(-1); Hc (and CaO2) decreased from 41.8% (19.8 ml x dl(-1)) to 29.6% (14.2 ml x dl(-1); P < 0.01). Vm-MCA increased from 61.2 cm x sec(-1) to 77.3 cm x sec(-1) (P < 0.01). Following RT, Vm-MCA decreased again, but remained higher than baseline (P < 0.01). PI decreased by 13% following RT (P < 0.05). There were no changes in RI, HR, BP SpO2 and P(ET)CO2. Regression lines could be fitted between Hc and Vm-MCA, Vm-MCA and CaO2, and between Hc and C(E)DO2. CONCLUSIONS: Transcranial Doppler changes in blood flow velocities correlated with the simultaneously recorded systemic Hc and CaO2 values. We found a 2% increase in CBFV for each 1% decrease in Hc and CaO2.

Adult↗
PubMed1999

[Quality documentation with an Anaesthesia Information Management System (AIMS)].

OBJECTIVE: In 1994 the Department of Anaesthesiology and Intensive Care Medicine of the Justus Liebig University of Giessen decided to implement an Anaesthesia Information Management System (AIMS) to replace the previous hand-written documentation on paper. From 1997 until the end of 1998 the data sets of 41,393 anaesthesia procedures were recorded with the help of computers and imported into a data bank. Individual aspects and results of this data pool are presented under the aspect of how the system in its present form is able to guarantee documentation of quality according to the requirements of the German Society of Anaesthesiology and Intensive Care Medicine (DGAI). METHODS: Since 1997 information on all anaesthesia procedures has been documented "online" with the anaesthesia documentation software NarkoData 4 (ProLogic GmbH, Erkrath). The data sets have been stored in a relational data bank (Oracle Corporation) and statistically processed with the help of the SQL-based program Voyant (Brossco Systems, Espoo, Finland). As an example of two adverse perioperative events (AVB) we compared incidences of "hypotension" and "nausea/vomiting", recorded by staff members into the AIMS, with the incidence of comparable events that were recorded with the help of online data during anaesthesia procedures, such as blood pressure and drug application. Since 1998 data recording has been revised constantly in department meetings; advanced training has been given. The results have been analysed critically. RESULTS: In 1997 the incidence of adverse perioperative events entered manually into the system was 3.6% (grade III and higher 0.9%) and increased during 1998 to 22.2% (grade III and higher 1.9%). The frequency of anaesthesia procedures with manually documented AVBs was significantly below the incidence (determined with the help of online data) of comparable events: "hypotension" (1.8% vs. 8.5%) and "nausea/vomiting" (4.9% vs. 8.3%). CONCLUSION: The current documentation of AVBs in almost any hospital is incomplete. In contrast to the hand-written procedure, the AIMS provides recorded data for evaluation and guarantees more detailed and complete quality documentation. In addition, the effort needed for documentation is reduced. Whether these data sets really describe and measure quality or not has to be evaluated. In addition it has to be considered whether different requirements (such as automatic AVB recognition for an AIMS) are advantageous for quality documentation regarding the data raster and the AVB recognition, with respect to different documentation procedures.

Anesthesia↗
PubMed1999

Preoperative microbiologic screening and antibiotic prophylaxis in pulmonary resection operations.

BACKGROUND: Pulmonary resection is associated with considerable risk of infection, so antibiotic prophylaxis has become routine practice in pulmonary operations. We studied two standard flash antibiotic prophylaxis regimens and matched them to preoperatively acquired microorganisms. METHODS: In 120 patients scheduled for elective pulmonary resection, aspirates were taken separately from the left and the right lung using a double-lumen tube. Then the patients received either 1.5 g of sulbactam plus ampicillin (n = 60; group 1) or 2 g of cefazolin (n = 60; group 2) intravenously as a single-shot antibiotic prophylaxis according to a prospective randomized sequence. When bacteria were found in the aspirates, both antibiotics were tested for susceptibility. The patients were monitored for the first 3 postoperative days with regard to bronchopulmonary infections. RESULTS: Fifty-eight pathogens were isolated from the 120 patients. The cultured bacteria did not differ significantly between the two groups. In group 1 all found bacteria were susceptible to the used antibiotic prophylaxis, whereas in group 2 eight of the 25 found bacteria were not susceptible to antibiotic prophylaxis. Postoperatively, group 2 showed significantly more signs of bronchopulmonary infections than the group 1 and subsequently needed additional antibiotics more often. Intensive care unit stay was longer in patients of group 2 and costs were higher for these patients. CONCLUSIONS: Preoperative microbiologic examination could be helpful to evaluate efficacy of the antibiotic prophylaxis regimen. Sulbactam plus ampicillin was significantly more effective than cefazolin.

Ampicillin↗
PubMed1999

Intraarticular, epidural, and intravenous analgesia after total knee arthroplasty.

BACKGROUND: After total knee arthroplasty, patients regularly suffer from severe pain. It is unclear whether epidural or systemic pain therapy is superior in terms of postoperative pain relief, patients' comfort and side effects. A new therapeutic approach, intraarticular opioids, has been suggested with the detection of opioid receptors in inflamed tissue. This method has proven suitable for clinical use in small operations (e.g. knee arthroscopy). In this study, we compared epidural analgesia and intraarticular application of morphine plus "on-demand" intravenous analgesia to "on-demand" intravenous analgesia alone. METHODS: Thirty-seven patients, scheduled for total knee arthroplasty, were randomly assigned to three treatment groups: in group 1 (EPI) patients received bolus doses of morphine via an epidural catheter; in group 2 (IA) an intraarticular bolus of 1 mg of morphine was applied at the end of the operation with subsequent use of a patient-controlled analgesia (PCA) pump; group 3 (Control), in which only PCA was provided, served as control for both analgesic procedures. Main outcome measures included visual analogue pain scales, total morphine consumption, and stress hormones. RESULTS: No statistically significant differences in visual analogue pain scales could be detected between the three groups. Application of intraarticular morphine did not reduce the amount of analgesics required for postoperative analgesia as compared to intravenous analgesia alone. Application of epidural morphine significantly suppressed beta-endorphine release, but did not significantly influence other stress hormones as compared to the control group. CONCLUSION: Epidural and intravenous analgesia after total knee arthroplasty are equivalent methods of pain relief. In major orthopaedic procedures, application of intraarticular morphine does not reduce analgesic requirements.

Adrenocorticotropic Hormone↗
PubMed1999

Cerebral blood flow velocity and carbon dioxide vasoreactivity during gamma-hydroxybutyrate/fentanyl anaesthesia in non-neurosurgical patients.

In this study the effects of gamma-hydroxybutyrate/fentanyl on cerebral blood flow velocity (CBFV) (as measured in the middle cerebral artery by transcranial Doppler ultrasonography) and on cerebrovascular carbon dioxide reactivity were investigated. Mean CBFV (Vmean) and haemodynamic responses were recorded in 12 non-neurosurgical patients before, during and after induction of general anaesthesia with gamma-hydroxybutyrate (GHB) (20 min constant rate infusion of 100 mg kg-1). Two patients were excluded, one because of bradycardia and the other because of severe myoclonia. During the infusion of GHB, normocapnia was maintained by manually assisting ventilation as necessary. The infusion of GHB did not affect Vmean [awake: 57 +/- 12 cm s-1 (mean +/- SD); 22.5 min: 62 +/- 15 cm s-1, NS difference] or mean arterial blood pressure (MAP) (awake: 97 +/- 12 mmHg; 22.5 min: 89 +/- 10 mmHg, NS). This suggests that cerebral blood flow velocity is unaltered by an anaesthetic dose of GHB. Twenty-five minutes after the start of GHB, fentanyl 3 micrograms kg-1 and vecuronium 0.1 mg kg-1 were given, the trachea was intubated and the lungs were mechanically ventilated to maintain end-tidal PCO2 of 4.6 +/- 0.4 kPa (30 min). At 30 min after the start of the GHB infusion, Vmean and MAP decreased to 38 +/- 10 cm s-1 and 76 +/- 12 mmHg (both P < 0.05 vs 22.5 min) respectively. After adjusting the ventilation to achieve hypocapnia (40 min: end-tidal PCO2 3.5 +/- 0.2 mmHg), Vmean decreased to 29 +/- 7 cm s-1, while MAP did not change. This allowed the relative vasoreactivity (percentage change in Vmean/0.133 kPa change in the end-tidal PCO2 from normocapnia to hypocapnia) to be estimated as 2.7 +/- 1.6% 0.133 kPa-1. This suggests that cerebrovascular response to CO2 during gamma-hydroxybutyrate/fentanyl anaesthesia is maintained.

Adolescent↗
PubMed1999

Effects of theophylline on human cerebral blood flow velocity during halothane and isoflurane anaesthesia.

The acute influence of therapeutic doses of theophylline on cerebral blood flow velocities during general anaesthesia induced either by halothane or isoflurane has not been elucidated previously. The aim of this study, was therefore to investigate these effects during steady state anaesthetic conditions in anaesthetized patients using transcranial Doppler sonography. Thirty-four Patients were investigated. Anaesthesia was maintained either with 1 MAC (minimum alveolar concentration) halothane (n = 16) or 1 MAC isoflurane (n = 18); FiO2: 40%; end-expiratory pCO2: normocapnia. Theophylline administration was performed before surgery by infusing 6 mg kg-1 over a period of 7.5 min. Measurements were recorded prior to theophylline administration, and immediately after 2 mg kg-1 (2.5 min), 4 mg kg-1 (5 min) and 6 mg kg-1 (7.5 min), as well as 5, 10, 15, 20, 30 and 45 min after theophylline administration. Recorded variables included blood pressure, heart rate, arterial oxygen saturation, end-expiratory pCO2, body temperatures, middle cerebral artery blood flow velocity and pulsatility index. Theophylline administration was well tolerated by all study subjects. Heart rate, blood pressure, body temperatures, arterial oxygen saturation and end-expiratory pCO2 remained constant during the whole examination period. Following theophylline, mean blood flow velocity decreased by 25% in the halothane and by 30% in the isoflurane group (P < 0.05). By the end of the examination period, mean blood flow velocity had not yet recovered to the initial values whereby in both groups the mean blood flow velocity was 26% below the initial values. In the isoflurane group, the pulsatility index increased by about 20% (P < 0.05) and remained high until the end of the examination. In the halothane group, however, there were no changes in the pulsatility index. Our results show a remarkable, significant and simultaneous decrease in blood flow velocity in the middle cerebral artery associated with theophylline administration during halothane and isoflurane anaesthesia in man.

Adult↗
PubMed1999

The influence of several intravenous anaesthetics on the chemotaxis of human monocytes in vitro.

Monocytes play a very important part in humoral as well as in cell-mediated immunity. At present, however, the knowledge of the influence of anaesthetic agents on the functions of monocytes is limited. In the present study, the effects of thiopentone, methohexitone, ketamine, midazolam, droperidol, propofol, etomidate, and fentanyl on monocyte chemotaxis were examined in vitro using a 48-well microchemotaxis chamber. Clinically relevant concentrations of ketamine, midazolam, and droperidol significantly (P < or = 0.05) inhibited chemotaxis. For that reason, it is possible that these anaesthetics impair the immunological system in vivo. This possibility should be further examined.

Anesthetics, Intravenous↗
PubMed1999

[Statistics and evaluation of a graphic SQL user interface in an anesthesia information management system (AIMS)].

PURPOSE: Since 1997, the Anaesthesia Information Management Systems (AIMS) in our department has produced extensive data material (DGAI core data, vital sign parameters, respiratory parameters, material consumed, etc.) which is stored in a relational data bank. The processing of this data by means of SQL queries was restricted to a few persons with special knowledge only. It was the objective of the project to create an evaluation tool which enables each member of the department to enter queries concerning topics such as efficiency records, quality management, training and research at any time. The tool was also intended to present results in an adequate form. METHODS: Since 1997, the data of the performed anaesthesia procedures have been recorded using the online anaesthesia documentation software NarkoData Version 4 (ProLogic GmbH, Erkrath) within the AIMS. The recorded data sets have been imported into a relational Oracle data bank (Oracle Corporation). The commercial programme Voyant (Brossco Systems, Espoo, Finland) enables for the user to formulate SQL-requests (Structured Query Language) with the help of a graphic user interface and to present the results in a variety of graphics and tables. Repetition of the evaluation using the current data is possible at any time. RESULTS: During 1997 and the first quarter of 1998, the data of 26,030 anaesthesia procedures have been registered and stored in the anaesthesiological data base. 235 queries could be formulated with the SQL-capable graphic tool Voyant. They are available to each member of the department by the application of NarkoStatistik (IMS GmbH, Giessen) within the AIMS, together with the corresponding documentation (HTML pages). The query catalogue covers the main topics of efficiency, quality management, organisation, diagnoses and surgery, pre-, intra- and postoperative data and day-care unit. Even without much previous experience with the system it is possible to carry out evaluations with the current data at selected AIMS terminals. Queries concerning other subjects can be created and can be integrated into the existing query catalogue. CONCLUSION: With the described application we are able to establish an evaluation tool which fulfils our expectations regarding user friendliness and the subjects the queries can cover. Today it has a central position within the AIMS. In addition to the anaesthesia documentation software and the data bank structure, the efficiency of an AIMS is mainly influenced by the corresponding evaluation tool.

Anesthesiology↗
PubMed1999

[Experiences fo three year's routine operation of an anesthesia information management system (AIMS) at a university clinic in Giessin].

PURPOSE: In 1994, the Department of Anaesthesiology and Intensive Care Medicine of the Justus Liebig University at Giessen decided to install an Anaesthesia Information Management System (AIMS). Individual aspects and results from routine operation are presented, demonstrating the quality of the documentation and the value of information at the anaesthesiological workstation. The paper discusses which adaptations are necessary according to the experience gathered. METHODS: For the installation of the system Apple Macintosh Clients (Apple Computer, Inc., Cupertino, California) and a File Server were integrated into the partially existing hospital network. The hospital network had to be enlarged during the project according to the Anaesthesiological requirements. The software of the Hospital Information System (HIS) and an HTML browser were installed at individual workstation computers in addition to the Anaesthesia documentation software NarkoData (ProLogic GmbH, Erkrath). The remote control software Timbuktu (Farallon, Alameda, USA) has been added to facilitate remote administration. The file administration programme FileWave (Wave Research, Berkeley, USA) is used for file distribution. Since 1995, all anaesthesia procedures have been documented with the system, either by online or postoperative recording. Since 1997, the recorded information has been stored in a relational Oracle 7 data bank (Oracle Corporation). RESULTS: From 1995 to 1997, 60,405 anaesthesiological procedures have been recorded with the help of this AIMS at 111 decentralised workstations. In 1997, 87.8% of the 21,130 performed anaesthesia procedures have been recorded online with the system and 12.2% postoperatively. From 1995 to 1997, the number of recorded procedures increased by 6.4% from 19,854 to 21,130. Because of lacking interfaces at some patient monitoring stations, the automatic recording of patient data could only be implemented at 69 workstations (62%). With the corresponding access rights, important patient information from the HIS (diagnoses, laboratory results, etc.), records of previous Anaesthesia procedures, numerous statistics, and the whole information from the hospital's intranet (including e-mail) are available at the anaesthesiological workstation at any time. CONCLUSION: The implementation of the AIMS and an effective user support have been able to increase significantly the quality of documentation, the flow of information at the anaesthesia workplace and the number of recorded Anaesthesia procedures. All recorded data can be analysed immediately The expansion of the automatic data transfer from the patient monitoring, interfaces to other computer subsystems of the hospital and a practicable evaluation programme are necessary for further enhancing the efficiency of the AIMS.

Anesthesiology↗
PubMed1999

Plasma levels of selectins and interleukins in cardiovascular surgery using cardiopulmonary bypass.

BACKGROUND: Cardiovascular surgery with cardiopulmonary bypass (CPB) leads to activation of a variety of inflammatory pathways, including the release of cytokines and selectins. METHODS: In 20 patients undergoing elective coronary artery bypass grafting, plasma levels of interleukins IL-2, -6, -8, -10, -12 and of P-, E-, and L-selectins were measured at eight time points before, during, and after CPB using a standardized ELISA technique. RESULTS: IL-2 plasma levels decreased significantly after the start of CPB and remained low until the second postoperative day. IL-6 and IL-8 levels increased significantly after weaning off CPB, with mean peak values six hours postoperatively. Very low IL-10 plasma levels were detectable preoperatively. They remained low during CPB and peaked significantly after weaning off CPB until skin closure. The IL-12 levels decreased after weaning off CPB (p < 0.05) until 6 hours postoperatively. The plasma levels of P-selectin showed no alterations, but concentrations of E- and L-selectin decreased after the start of CPB (p < 0.05). There were no adverse postoperative events. CONCLUSIONS: The results of our study demonstrate a dysregulation of cytokine and selectin production during and up to 48 h after CPB, which may be a "normal" stress reaction to CPB.

Adult↗
PubMed1999

Effect of bupivacaine on ATP-dependent potassium channels in rat cardiomyocytes.

Bupivacaine induces fatal arrhythmia when accidentally injected i.v. or overdosed, whereas lidocaine is used as an anti-arrhythmic agent. We have suggested recently that the anti-arrhythmic effect of lidocaine may be explained by suppression of ATP-sensitive potassium (KATP) channels. Therefore, it could be argued that different sensitivities of KATP channels to both drugs could be a reason for their different arrhythmic and anti-arrhythmic properties. In this study, we have investigated the direct action of bupivacaine on KATP channels in cardiomyocytes. The effects of bupivacaine on the cardiac KATP channel were investigated using the patch-clamp technique on enzymatically dissociated cardiomyocytes of adult rats. Bupivacaine was applied to the outer side of excised membrane patches using a multiple-barrel perfusion system. Concentration-response curves indicated that bupivacaine blocked the mean current of the KATP channels at a half-maximum inhibiting concentration (IC50) of 29 mumol litre-1, similar to that reported for lidocaine (43 mumol litre-1). Binding of bupivacaine influenced the gating of this channel, but did not reduce the conductance of the open channel. Bupivacaine and lidocaine were equipotent in blocking KATP channels. However, because of its excessive block of the sodium channel in the inactivated state, block of KATP channels by bupivacaine will only enhance its cardiotoxicity.

Adenosine Triphosphate↗
PubMed1999

Effects of i.v. anaesthetic agents on the chemotaxis of eosinophils in vitro.

Polymorphonuclear eosinophilic leucocytes (PME) participate in wound healing processes, the inflammatory response, bronchial asthma, allergies and defence against invading parasites. We have examined the effects of thiopental, methohexital, propofol, etomidate and ketamine on PME chemotaxis in vitro. PME were isolated from venous blood samples of 10 healthy volunteers using multi-stage Percoll gradient centrifugation. Eosinophilic chemotaxis was determined using a 48-well microchemotaxis chamber. Thiopental 150 micrograms ml-1 and etomidate 0.32 microgram ml-1 caused significant (P < or = 0.05) inhibition of PME chemotaxis. We conclude that thiopental and etomidate may have an adverse influence on wound healing processes and parasitic diseases. Further studies are recommended.

Analgesics↗
PubMed1999

Stereoselectivity of bupivacaine in local anesthetic-sensitive ion channels of peripheral nerve.

BACKGROUND: The local anesthetic bupivacaine exists in two stereoisomeric forms, R(+)- and S(-)-bupivacaine. Because of its lower cardiac and central nervous system toxicity, attempts were made recently to introduce S(-)-bupivacaine into clinical anesthesia. We investigated stereoselective actions of R(+)-and S(-)-bupivacaine toward two local anesthetic-sensitive ion channels in peripheral nerve, the Na+ and the flicker K+ channel. METHODS: In patch-clamp experiments on enzymatically demyelinated peripheral amphibian nerve fibers, Na+ and flicker K+ channels were investigated in outside-out patches. Half-maximum inhibiting concentrations (IC50) were determined. For the flicker K+ channel, simultaneous block by R(+)-bupivacaine and S(-)-bupivacaine was analyzed for competition and association (k1) and dissociation rate constants (k(-1)) were determined. RESULTS: Both channels were reversibly blocked by R(+)- and S(-)-bupivacaine. The IC50 values (+/- SEM) for tonic Na+ channel block were 29+/-3 microM and 44+/-3 microM, respectively. IC50 values for flicker K+ channel block were 0.15+/-0.02 microM and 11+/-1 microM, respectively, resulting in a high stereopotency ratio (+/-) of 73. Simultaneously applied enantiomers competed for a single binding site. Rate constants k1 and k(-1) were 0.83+/-0.13x10(6) M(-1) x S(-1) and 0.13+/-0.03 s(-1), respectively, for R(+)-bupivacaine and 1.90+/-0.20x10(6) M(-1) x s(-1) and 8.3+/-1.0 s(-1), respectively, for S(-)-bupivacaine. CONCLUSIONS: Bupivacaine block of Na+ channels shows no salient stereoselectivity. Block of flicker K+ channels has the highest stereoselectivity ratio of bupivacaine action known so far. This stereoselectivity derives predominantly from a difference in k(-1), suggesting a tight fit between R(+)-bupivacaine and the binding site. The flicker K+ channel may play an important role in yet unknown toxic mechanisms of R(+)-bupivacaine.

Anesthetics, Local↗