Biomedical subjects

K Hörauf

Publications and source records attributed to K Hörauf.

16 recordsLinked to original sources

PubMed2001

Impact of early high caloric duodenal feeding on the oxygen balance of the splanchnic region after severe burn injury.

Early enteral nutrition is recommended in burned patients. Depending on the amount administered, enteral feeding causes an increase of intestinal oxygen-demand. Although early moderate enteral nutrition has been shown to be beneficial, early high calorie enteral nutrition might lead to an imbalance of the O(2)-balance of the gut since intestinal perfusion is decreased after major burns. In 20 severely burned patients during the first 48 h of early high caloric duodenal feeding an assessment of the CO(2)-gap between the arterial and the gastric CO(2), as parameter for the intestinal O(2)-balance, was performed. Time points were prior to starting the enteral nutrition (BASE) subsequently every 30 min after increasing the amount of nutrition administered and from the 11th to the 48th h after beginning of nutrition in intervals of 6 h. In none of the patients was the CO(2)-gap increased during the rapid increase of enteral nutrition. On the contrary the CO(2)-gap decreased significantly. We conclude that high caloric duodenal feeding in the early hypodynamic postburn phase does not have adverse effects on the oxygen balance of the intestine.

Adult↗

PubMed2001

The influence of deliberate hypotension on splanchnic perfusion balance with use of either isoflurane or esmolol and nitroglycerin.

UNLABELLED: Various techniques to induce deliberate hypotension (DH) have different influences on splanchnic perfusion. The aim of our study was to determine whether splanchnic perfusion is clinically impaired during DH by using either isoflurane (ISO) or a combination of esmolol and nitroglycerin (E/N). We randomized 16 patients undergoing elective maxillofacial surgery to receive either ISO (0.7%-1.8%) or E (105 g x kg(-1) x min(-1)) and N (1-6 mg/h) to induce DH. General anesthesia was performed in both groups by IV midazolam 0.07 mg/kg, fentanyl 0.003 mg/kg, propofol 1.5 mg/kg, and vecuronium 0.1 mg/kg followed by a propofol infusion with 6 mg x kg(-1) x h(-1). After the induction of anesthesia, a gastric tonometer (TRIP NGS Catheter) and a radial artery catheter were inserted. Baseline values of gastric intramucosal pH (pHi) were determined 60 min after placement of the catheter and before the induction of DH. The pHi values were calculated every 60 min until DH was discontinued. In both groups, DH was satisfactorily established. None of the pHi values calculated was less than 7.37 in the E/N or 7.41 in the ISO group. Arterial blood lactate levels did not increase in any of the patients. We conclude that neither method of producing DH compromises splanchnic tissue oxygen balance in healthy patients. Furthermore, overall organ perfusion was sufficient in both groups, because none of the patients showed an increase in blood lactate. IMPLICATIONS: Neither the isoflurane nor the esmolol/nitroglycerin method of producing deliberate hypotension compromises splanchnic tissue oxygen balance in healthy patients. Furthermore, overall organ perfusion was sufficient in both groups, because none of the patients showed an increase in blood lactate.

Adrenergic beta-Antagonists↗

PubMed1999

[Use of electrocardiographic placement control of central venous catheters in Austria].

After placement of a central venous catheter the correct position of the catheter tip has to be verified. The use of intravascular ECG tracing via a guide-wire or via the saline-filled lumen of the catheter enables immediate and safe control of the position. Only if complications (e.g. pneumothorax) are suspected, further clinical and radiological diagnostics are necessary. Up to now, no data on the routine clinical use of this method are available. In April 1998, a semi-structured questionnaire was sent to the 518 heads of anaesthesiological, surgical and medical departments in Austria (33% of the questionnaires were returned). The subclavian (56%) and internal jugular veins (35%) are most frequently used for catheter insertion in Austria. Verification of the catheter tip placement by ECG-guidance is used in only 8% of cases, while radiographs are performed in most cases. Uncertainty with respect to forensic consequences of using the ECG-guidance for control of the catheter tip placement and the possible necessity of an additional radiograph are the main problems seen by the heads of the departments. After placement of a central venous line, measures for the verification of the catheter tip and measures for the control of possible complications have to be considered separately. Intravascular ECG tracing is unable to detect complications. Concerning the verification of the catheter tip position many studies confirm the easy handling, relevance of results and cost savings for this method. Its use for the control and documentation of the tip location is considered a standard. In Austria the consequent use of the method would offer the chance for significant reductions of treatment costs.

Austria↗

PubMed1998

[Interscalene plexus block for mobilizing chronic shoulder stiffness].

INTRODUCTION: After mobilisation of a frozen shoulder, patients should work with a physiotherapist one to two times a day. In the remaining time patients must exercise on their own: otherwise, the shoulder is likely to become less mobile. Exercise is only possible in the absence of pain. Therefore, adequate analgesic therapy for four to five days after the first mobilisation is of great importance. We used interscalene blockade of the brachial plexus to achieve mobilisation in patients suffering from a painful frozen shoulder. We investigated the efficacy of this technique by registering the use of additional analgesics and documenting the patient's assessment. The observation time was 18 months. METHODS: Thirty-seven patients were treated with a plexus block using a catheter inserted at the affected side. Catheter location was verified with electric nerve stimulation. In all patients a bolus of 20 ml bupivacaine 0.375% was given for initial mobilisation, followed by 10 ml bupivacaine 0.25% every 6 hours. RESULTS: In 34 of 37 (92%) patients, the shoulder could be mobilised without general anaesthesia. Thirty-three of 37 (89%) patients did not need any additional analgesics during the following mobilizations. The mean duration of catheter treatment was 4 days; no infections occurred. The following side effects were observed at the first mobilisation: Horner's syndrome in 20 patients (54%), paresis of the recurrent nerve in 9 patients (24%) and paresis of the phrenic nerve in 6 patients (16%). During subsequent treatment, Horner's syndrome was observed in 15 patients (41%) and a paresis of the recurrent nerve in 8 patients (22%). In an interview after the end of the treatment period all patients stated that they would use this method again if necessary. CONCLUSIONS: With the use of this regional anaesthesia technique it was possible to provide comfortable pain therapy during the mobilisation period. In order to achieve sufficient analgesia with only a mild motor blockade of the motoneurons, the exact location of the catheter tip is important. The latter can be verified by electrical stimulation.

Adult↗

PubMed1998

Magnesium sulfate reduces intra- and postoperative analgesic requirements.

UNLABELLED: In a randomized, double-blind study with two parallel groups, we assessed the analgesic effect of perioperative magnesium sulfate administration in 46 ASA physical status I or II patients undergoing arthroscopic knee surgery with total i.v. anesthesia. The patients received either magnesium sulfate 50 mg/kg preoperatively and 8 mg.kg-1.h-1 intraoperatively or the same volume of isotonic sodium chloride solution i.v. Anesthesia was performed with propofol (2 mg/kg for induction, 6-8 mg.kg-1.h-1 for maintenance), fentanyl (3 micrograms/kg for induction), and vecuronium (0.1 mg/kg for intubation). Intraoperative pain was defined as an increase of mean arterial blood pressure and heart rate of more than 20% from baseline values after the induction of anesthesia and was treated with bolus fentanyl (1-2 micrograms/kg). Postoperative analgesia was achieved with fentanyl (0.5 microgram/kg) and evaluated using the pain visual analog scale for 4 h. During the intraoperative and postoperative periods, patients in the magnesium group required significantly less fentanyl than those in the control group (control group 0.089 +/- 0.02 microgram.kg-1.min-1 versus magnesium group 0.058 +/- 0.01 microgram.kg-1.min-1; P < 0.05 and control group 0.021 +/- 0.013 microgram.kg-1.min-1 and magnesium group 0.0031 +/- 0.0018 microgram.kg-1.min-1; P < 0.01 for intraoperative and postoperative periods, respectively). We conclude that, in a clinical setting with almost identical levels of surgical stimulation, i.v. magnesium sulfate administration reduces intraoperative and postoperative analgesic requirements compared with isotonic sodium chloride solution administration. IMPLICATIONS: The perioperative administration of i.v. magnesium sulfate reduces intra- and postoperative analgesic requirements in patients with almost identical levels of surgical stimulus. Our results demonstrate that magnesium can be an adjuvant to perioperative analgesic management.

Adult↗

PubMed1997

[Anesthesia for magnetic resonance tomography in neonates, infants and young children].

INTRODUCTION: Since patient cooperation in neonates and infants up to 5 years is always reduced, deep sedation is usually recommended to obtain constant high-quality images during MRI. According to the widely accepted AAP Guidelines, deep sedation is not always distinguishable from general anesthesia, substantiating the demand for state-of-the-art anaesthesia. This is particularly true in this age group, where pharmacokinetics and pharmacodynamics show wide interindividual variation. In this review we outline the techniques required to provide safe and effective patient care in the unique MRI environment. CHOICE OF DRUGS AND PROCEDURE: From the viewpoint of induction time, half-life of action and success rate, we have found that inhalation anesthetics and propofol present clear advantages. Both offer rapid induction and emergence, allowing outpatient examinations in a tight schedule with a reliable sedation state. Tracheal intubation or a laryngeal mask airway is required to supply volatile anesthetics and to secure the airway, since propofol in appropriate doses causes respiratory depression and loss of the protective reflexes. Positive-pressure ventilation is recommended since the reduction of tidal volumes by sedative drugs (including high-dose chloral hydrate, barbiturates) may cause atelectasis and decreased oxygen saturation. ANESTHESIA MACHINES: Several respirators work well outside a critical magnetic field strength of 10 mT (e.g. Draeger: Titus, Siemens: Servo 900). The use of long low-compliance tubing (4-5 m) allows the respirator to be placed at the distal end of the patient table. Sidestream capnometry and spirometry at the proximal tube connector facilitate compensation for losses in tidal volume due to gas compression. Syringe pumps work properly when kept outside the 10 mT line. Some defibrillators (e.g., Lifepac, Physiocontrol) are approved for use in strong magnetic fields. MONITORING: State-of-the-art monitoring is also attainable for high-risk patients, including invasive pressure measurement. Since wiring without special filters may not cross the HF shield of the examination room, hydraulic and pneumatic systems are used (blood pressure by oscillometry, airway monitoring by side-stream spirometry). Optical fibers are used for pulse oximetry. A telemetric EKG is usually provided by the MRT manufacturer. Because oscilloscopes are distorted by the magnetic field, the monitors are placed outside the examination room. In addition, this eliminates the possibility of erasing the EPROMs contained in most monitors. PERSONNEL: With the setup described, the presence of a second anesthetist within the examination room is superfluous. A second anesthesia team can shorten the time lag between examinations by overlapping induction if a separate anesthesia induction and emergence room is provided. CONCLUSION: The level of sedation required for MRI in newborn and infants can only be achieved safely and efficiently by general anesthesia performed by trained staff. Complete state-of-the-art anesthesia care can be delivered if appropriate instrumentation is used.

Anesthesia, General↗

PubMed1994

[Emergence times, hemodynamics and adverse effects of sevoflurane and isoflurane: an open, randomized, comparative phase iii study].

Sevoflurane is a "new" volatile inhaled anaesthetic that is currently undergoing phase III clinical trial in Europe and the United States. Owing to the low blood solubility, rapid induction of anaesthesia and emergence from anaesthesia would be expected. In this study, we compared emergence times and haemodynamics in patients receiving either sevoflurane or isoflurane. Furthermore, all adverse effects were recorded and the relationship to the drug administered was rated. METHODS. Fifty ASA physical status I and II patients were studied in an open, prospective, randomised clinical trial. Anaesthesia was induced with fentanyl, thiopentone, and vecuronium for facilitating endotracheal intubation and maintained with sevoflurane or isoflurane, 60% nitrous oxide (N2O) in oxygen (O2), and additional doses of fentanyl (1-2 micrograms/kg.h). The electrocardiogram, blood pressure (non-invasive), O2 saturation, temperature, and end-tidal concentrations of sevoflurane or isoflurane, N2O, and carbon dioxide were monitored continuously. At the end of surgery, administration of sevoflurane or isoflurane and N2O was discontinued without tapering and emergence times were recorded. All adverse events that occurred until the 3rd postoperative day were recorded and the relationship to the inhaled anaesthetic was rated as "none", "unlikely", "possible", "probable", or "highly probable". RESULTS. With the exception of gender, the two patient groups were comparable (Tables 1 and 2). Due to the higher MAC value, mean end-tidal concentrations were higher for sevoflurane (0.82% vs. 0.59% for isoflurane). The duration of anaesthetic exposure was 1.3 MAC h (calculation with FIO2 = 1.0 MAC value) and 3.1 MAC h (calculation with FIO2 = 0.4 in N2O MAC value), respectively, for both inhaled anaesthetics. Pulmonary elimination was faster (Fig. 1) and emergence time shorter (7 min vs. 11.5 min, Table 3) with sevoflurane. There was no difference in the time courses of heart rate and mean arterial blood pressure (Figs. 2 and 3). No adverse effects with a "probable" or "highly probable" relationship to the inhaled anaesthetic were observed. Table 4 shows the adverse events with a possible relationship to the drug administered. Further evaluations of nausea, vomiting, and dizziness are shown in Table 5. DISCUSSION. Emergence time after inhalation anaesthesia depends on pulmonary elimination and MACawake, that is, the end-tidal concentration that would allow opening of the eyes on verbal command. Pulmonary elimination depends on dose applied (MAC h), alveolar ventilation, and blood-gas solubility coefficient. Due to the lower blood-gas solubility coefficient (0.6-0.7 for sevoflurane vs. 1.3-1.4 for isoflurane) and in accordance with the investigations of Frink et al. [4] and Smith et al. [16], emergence time was significantly shorter with sevoflurane. Gender, the only difference between the two patient groups, does not influence pulmonary elimination and MACawake [8]. Supplementing inhalation anaesthesia with fentanyl, there was no difference in the time courses of heart rate and mean arterial blood pressure between sevoflurane and isoflurane. Adverse events with a possible relationship to the inhaled anaesthetic occurred in both groups.

Adult↗

PubMed1972