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Biomedical subjects

W F List

Publications and source records attributed to W F List.

At least 19 recordsLinked to original sources
PubMed1999

Total intravenous anesthesia with remifentanil, propofol and cisatracurium in end-stage renal failure.

PURPOSE: To compare recovery parameters of total intravenous anesthesia (TIVA) with remifentanil and propofol, hemodynamic responses to perioperative events, and pharmacodynamic parameters of cisatracurium in 22 end-stage renal failure and 22 normal renal function patients. METHODS: Anesthesia was induced with 2-3 mg x kg(-1) propofol and 1 microg x kg(-1) remifentanil and maintained with 75 microg x kg(-1) x min(-1) propofol and propofol initial infusion of 0.2 microg x kg(-1) x min(-1) propofol. Arterial pressure and heart rate were maintained by remifentanil infusion rate adjustments. The first twitch (T1) was maintained at 25% by an infusion of cisatracurium. RESULTS: There was no difference in the time to maintenance of adequate respiration, date of birth recollection, first analgesic administration, between the renal failure (4.8+/-2.5, 7.8+/-3.2, 12.3+/-5.3 min respectively) and the control group (5.2+/-2.8, 8.1+/-3.1, 12.7+/-5.5 min): nor were there any differences in the time to 25% T1 recovery, T1 recovery from 25% to 75%, or cisatracurium infusion rate between the renal failure group (32.1 +/-10.8 min, 18.2+/-5.5 min, 0.89+/-0.29 microg x kg(-1) min(-1) respectively) and the control group (35.9 (7.9 min, 18.4+/-3.8 min, 0.95+/-0.22 microg x kg(-1) x min(-1)). CONCLUSION: End-stage renal failure does not prolong recovery from TIVA with remifentanil and propofol, or the recovery from cisatracurium neuromuscular block.

Adult↗
PubMed1999

Comparison of a new piezoelectric train-of-four neuromuscular monitor, the ParaGraph, and the Relaxometer mechanomyograph.

The ParaGraph is a new device for monitoring neuromuscular function using a piezoelectric motion sensor. In 20 patients, monitoring of neuromuscular block produced by cisatracurium 0.1 mg kg-1 was compared using the ParaGraph and a Relaxometer 2 mechanomyograph. The ParaGraph was quick to set up, and easy to operate and interpret. There were no significant differences in the time to 100% depression of T1/T0, time to 25% recovery of T1/T0 or time to recovery of T1/T0 from 25% to 75%, measured by the two monitors. When the difference between the two monitors was plotted against the average of the two measurements, the limits of agreement for T1/T0 (-42.95, +53.98%) and the train-of-four ratio, T4/T1 (-0.28, +0.21) were too wide to allow the values given by the two monitors for individual patients to be used interchangeably.

Adolescent↗
PubMed1998

[Hypertonic-hyperoncotic solutions: possibilities and limits].

Hypertonic-hyperoncotic solutions are a supplementary possibility in the acute treatment of hypovolemia. The main mechanism of action of this solution is, induced by the tonicity of the infusion (approximately 2400 mOsm/l), the transcapillary fluid shift from the intracellular and interstitial to the intravascular compartment. Additionally the fluidity of blood is improved (due to an increase in the diameter of the capillaries), the adherence of leucocytes to the endothelial wall is reduced, and the arteriolar vasomotion is restarted. Due to the available prehospital and clinical results it can be concluded, that hypertonic-hyperoncotic solutions offer advantages compared to conventional fluid therapy regimes: rapid stabilization of hemodynamics, reduction of posttraumatic volume deficiency, of posttraumatic edema and of posttraumatic complications and an improvement of the outcome of the patients. If the therapeutic recommendations are followed, such as a dose of 4 ml/kg body weight, infusion time of about 3-5 minutes and after the end of the infusion application of colloids or crystalloids in an amount as needed, no side effects will occur. Only immediately after the end of infusion sodium, chloride and osmolarity will slightly increase, however these parameters will normalize within the first posttraumatic day. Hypertonic-hyperoncotic solutions are trigger-solutions, as with the infusion of these types of solution it is possible to restore hemodynamics adequately and to prevent shock-induced complications.

Blood Volume↗
PubMed1998

[Karl E. Hammerschmidt. Humanist, natural scientist and pioneer in anesthesia].

Karl Eduard Hammerschmidt was born in Vienna in 1801. There are indications that after studying law he passed on to studies in medicine and surgery in Vienna, though it has to be said there is no trace of his attaining any qualification. After this he worked in various scientific sectors and in recognition of his achievements he was accepted as a member of the Kaiser Leopold Academy of Researchers in Natural Sciences in Bonn. From February 1847 to March 1848 he induced numerous general anaesthetics with ether, working with Dr. J. Weiger, a dentist in Vienna. On 11 July 1847 he published preliminary statistics based on 1560 dental operations performed under ether anaesthesia and also on numerous experiments performed on himself and investigations conducted with ether in animals and in healthy subjects. From the viewpoint of scientific research into and widening of the applications of ether anaesthesia, his most meritorious achievements include the early publication of a staging classification for ether anaesthesia, the introduction of an anaesthetic protocol for patients that also lent itself to data recording for statistical purposes and the early realization that the ability to hear is retained for a very long time during anaesthesia. In 1848 Hammerschmidt was obliged to flee to Istanbul by way of Hungary because of his involvement in the October Revolution. Once there, he continued to work as a doctor and later became Professor of Medicine at the University of Istanbul. He converted to Islam, taking the name of Abdullah Bey, and also became a colonel in the Turkish army. He was one of the founders of the Red Crescent, the humanitarian sister organization of the Red Cross, and the Turkish Post commemorated this with the issue of a stamp honouring him when the organization celebrated the centenary of its formation in 1968. In 1869 the Hapsburg dynasty also honoured him with orders and distinctions. He died in Istanbul in 1874 as a highly esteemed personage.

Anesthesiology↗
PubMed1998

Perioperative ventricular dysrhythmias in patients with structural heart disease undergoing noncardiac surgery.

UNLABELLED: Noncardiac surgical patients with preoperative ventricular dysrhythmias and structural heart disease may be at increased risk of adverse cardiac outcome. We evaluated how anesthesia and surgery affect the course of ventricular dysrhythmias (premature ventricular beats [PVB] and repetitive forms of ventricular beats [RFVB]: couplets and nonsustained ventricular tachycardia) noted preoperatively in patients with structural heart disease and whether the frequency of ventricular dysrhythmias affects cardiac outcome. In a prospective study, 70 patients scheduled for noncardiac surgery with structural heart disease and RFVB on preoperative Holter electrocardiogram were continuously monitored intraoperatively and for 3 days postoperatively. Holter tracings were analyzed for rhythm, medians of total PVB and RFVB per hour. Preoperative RFVB recurred intraoperatively in 35% and postoperatively in 87% of patients. There was a significant intra- and postoperative decrease of total PVB per hour (P < 0.05) and RFVB per hour (P < 0.01). Frequency of ventricular dysrhythmias in the five patients suffering adverse outcome (unstable angina, n = 1; congestive heart failure, n = 4) did not significantly differ from those with good outcome. We conclude that in noncardiac surgical patients with structural heart disease and RFVB, the frequency of ventricular dysrhythmias is not associated with adverse cardiac outcome. IMPLICATIONS: Using continuous electrocardiogram monitoring, we investigated whether the frequency of perioperative ventricular dysrhythmias independently affects outcome in patients with structural heart disease undergoing noncardiac surgery. The incidence of perioperative dysrhythmia in patients with an adverse outcome (8%) did not differ from those with a good outcome.

Adult↗
PubMed1997

[Ethics in intensive medicine].

In more than 30 years of development of intensive care medicine (ICM), our specialty has acquired moral and ethical standpoints, although not without public pressure and discussions. Special commissions dealing, e.g., with brain death, terminal care, ethics of foregoing life-sustaining treatment in the critically ill, withholding or withdrawing mechanical ventilation, and other issues have been formed in a number of medical societies. International consensus conferences have helped to clarify some of the issues. With increasing experience, a multitude of ethical problems have arisen in ICM that have to be dealt with, such as the issue of quality of life. What is an unworthy life? Are we allowed to make judgments for our patients? What is cost-effectiveness in ICM? Other restrictions include bed and equipment shortages in the intensive care unit (ICU), the necessity for triage--undisputed in catastrophe medicine--and how one should proceed in managing elective patients? In situations of limited ICU bed availability, sicker patients will be admitted, sparing out patients who are less ill for observation and those with poor quality of life and poor prognosis. For the future, it will likely be necessary to define the patients who should be admitted to an ICU more than those who should not be admitted. An ICU treatment entitlement index would be directly proportional to the probability of successful outcome and the quality of the remaining life, and would be inversely related to costs for achieving success. The ICU outcome with survival, hospital mortality, and follow-up of ICU patients is considered. DNR (do not resuscitate), the dying patient, terminal care, terminal weaning--DNT (do not treat)--active and passive euthanasia, living wills, quality of life, and cost-effectiveness for ICU patients are defined. Their application in the ICU will be discussed and problems pointed out. Outcome predictions using scores (APACHE III, SAPS II, MPM) have been developed based on previous experience, but should only be applied to patient groups and for quality assurance in ICUs. The most frequent and difficult problem in the ICUs is the vegetative state, which requires an exact diagnosis. The differential diagnosis from other comatose states such as coma, brain death, and locked-in-syndrome is depicted. The ethics of interrupting life-sustaining treatment in critically ill patients have been worked out by a Task Force on Ethics of the Society of Critical Care Medicine (1990). A consensus was found that the patient may judge to forego therapy; ethically it is then appropriate to withhold or withdraw therapy. According to the consensus, withdrawing an already initiated treatment should not necessarily be regarded as more problematic than a decision not to initiate treatment. In my mind, however, there is a great difference between withdrawing or withholding, e.g., ventilation. A dissentive opinion by some members of the Task Force stated that hydration and nutrition other than high-technology or parenteral nutrition are key components of patient care, and should not be equated with medical intervention. The ethical problems associated with active euthanasia (physician-assisted suicide or death) as practised in the Netherlands are also discussed. In most countries this practice seems unacceptable. From 30 years experience in ICM, there are many more ethical questions and case reports without clear solutions. Care decisions for single patients in unacceptable situations should be made after medical evaluation by the intensivist with the medical team and, if possible, by the patient and/or his or her surrogate. Legislation and solutions cannot be expected for single patients, but ethics committees could be helpful in decision-making.

Critical Care↗
PubMed1997

[The anesthesiologic risk patient. Preoperative evaluation, intraoperative management and postoperative monitoring].

A high-risk patient is a challenge to the anaesthesiologist. If surgical intervention is indicated the perioperative anaesthesiological management has to be carefully adapted to the requirements of the patient. If the patient is classified a high-risk at the preoperative anaesthesiological assessment, the therapeutic management has to aim at optimizing the patient's preoperative physical status. Intraoperatively, the minimal monitoring standards have to be extended by addition of specific non-invasive or invasive monitoring techniques to observe the intraoperative cardiovascular or pulmonary function according to the patient's preoperative disease. There are no recommendations about the choice of the anaesthesia techniques; the decision for general or regional anaesthesia depends on the site of operation and is guided by the individual experience of the anaesthesiologist. During the postoperative period each high-risk patient has to be observed in the intensive care unit to continue intraoperative monitoring and therapy. Patients at risk of postoperative myocardial ischaemia or infarction should be closely monitored for 3-5 days postoperatively. The perioperative risk of morbidity and mortality associated with elective surgical procedures has to be evaluated for each patient and the risk-benefit analysis discussed in a interdisciplinary dialogue involving the surgeon, the patient and the patient's family.

Anesthesia, Conduction↗
PubMed1997

Assessment of accelerography with the TOF-GUARD: a comparison with electromyography.

The TOF-GUARD is a new device for monitoring the neuromuscular function using acceleration measurement. It is quick and easy to apply and does not require a rigid support for the arm. Forty-one patients were studied to assess the monitoring of vecuronium neuromuscular block (NMB) using accelerography by the TOF-GUARD compared with electromyography by the Relaxograph. Although the mean first twitch (T1%) and mean train-of-four (TOF) ratios measured by the TOF-GUARD corresponded to a certain extent with the Relaxograph, the wide variations of the values for individual patients measured by the TOF-GUARD compared with the Relaxograph and the differences in clinical duration and recovery index between the two monitors do not allow the values of the two monitors to be used interchangeably. The levels at intubation as well as at full recovery of the patients can be assessed equally by the two monitors. Thus, the TOF-GUARD is a reliable clinical monitor in daily anaesthesia practice.

Adolescent↗
PubMed1997

Pain treatment in the ICU: intravenous, regional or both?

Adequate treatment of pain in ICU patients should be an integral part of ICU management, as inadequately treated pain leads to a series of complications that may counteract the success of ICU treatment. For continuous intravenous use we recommend sufentanil in a dose of 0.75-1.0 microgram kg-1 h-1 in mechanically ventilated patients and in a dose of 0.25-0.35 microgram kg-1 h-1 in intubated and spontaneously breathing patients. On-demand analgesia, administered via the intravenous or epidural route, may be an alternative to a relatively fixed continuous infusion of an analgesic drug, and in some ICU patients the transdermal use of opioids can be an alternative to continuous intravenous drug application or PCA. Increased sizes of the patch (25, 50, 75, 100 cm2) provide sustained transdermal rates of approximately 25, 50, 75 and 100 micrograms h-1 of fentanyl over a period up to about 72 hours. Patients with trauma to the thorax, pelvic fracture, or after major surgical interventions will be better managed by regional application of analgesic drugs alone or in combination with a systemic analgesic drug infusion. To achieve the best results it is necessary to be well informed and trained in the method, to know the advantages and disadvantages, the correct and modified dosages of the drugs used, and the indications and contraindications.

Administration, Cutaneous↗
PubMed1997

Iatrogenic ruptures of the tracheobronchial tree.

We did a retrospective study in 12 patients with iatrogenic tracheal or tracheobronchial ruptures treated since 1975. Ten female subjects, one male subject, and one child (age range, 8 to 72 years), all of whom had undergone intratracheal intubation, were admitted to the hospital. Four patients had been intubated with a double-lumen catheter (two Carlens type with carinal spur, two Robertshaw without spur), and seven had had "high volume-low pressure" tubes, placed under emergency conditions in three of those seven cases. In one further case, an unsuccessful attempt of percutaneous tracheostomy had been made. The localization of the ruptures (all of them longitudinally in the membranaceous wall; length, 2 to 13 cm; mean, 7 cm) comprised both cervical and intrathoracic trachea in seven, the intrathoracic trachea in three instances, and the left main stem bronchus in two cases. Ten patients had mediastinal and subcutaneous emphysema, seven presented with a pneumothorax, and nine had intratracheal bleeding. The interval until the onset of symptoms and diagnoses differed widely: twice diagnoses were made intraoperatively, during thoracic surgery. The longest interval until diagnosis was 5 days; only then did the patient show subcutaneous emphysema and have retrosternal pain. All patients had surgical repair. Nine recovered without sequelae, and three died of septic multiorgan failure.

Adult↗
PubMed1996

[Preclinical blood gas analysis. Technical description--initial experiences--indications].

OBJECTIVE: A new portable device for blood gas analyses (BGA) has been examined for prehospital application. METHODS: After a 1 h introduction to the procedure, two physicians used the blood gas analyzer in the emergency medical system in Graz, Austria, for 7 months. The indications for prehospital BGA were prolonged cardiopulmonary resuscitation, mechanical ventilation, hyperventilation for reducing increased intracranial pressure, respiratory failure and metabolic disorders. All patients tested were also checked with pulse oximetry and capnography. TECHNICAL SPECIFICATION: The device measures pO2, pCO2 and pH using the fluorescence method. The innovation of a single-use cassette system makes it unnecessary to do any calibrations or transport any test substances. The storage battery measures eight samples without recharge. The time spent on one measurement is 3-6 min. RESULTS: We took 49 samples from 24 patients and found 16 indications for therapeutical intervention, such as buffering metabolic acidosis and adjusting mechanical ventilation by means of BGA. In all cases the analyzer worked reliably. CONCLUSIONS: One advantage of BGA over the non-invasive methods pulse oximetry and capnography is that it does not interfere with factors like peripheral vasoconstriction or inequality of the pulmonary ventilation/ perfusion ratio. Moreover, it is the only method for controlled buffering of acid-base disturbances. This means more security in diagnostics and therapeutical interventions for the patient in danger of dying. The device has proved to be a useful addition to the monitoring methods for prehospital application.

Acid-Base Equilibrium↗
PubMed1996

The inhibition of serotonin evoked bovine coronary artery contraction by halothane, isoflurane and sevoflurane is endothelium-independent.

The present study was designed to determine the direct effects of halothane, isoflurane and sevoflurane on the bovine epicardial coronary artery as well as their mode of action. We chose serotonin as the vasoconstrictor because it also causes endothelium-dependent relaxation of coronary arteries. Isolated spiral strips of bovine epicardial coronary artery with and without endothelium were suspended for isotonic contraction recordings in Tyrode's solution. KCl (80.4 mM) solution induced maximal contraction, regarded as the reference value (100%). The muscle strips were then exposed to increasing concentrations of serotonin from 10(-8) to 10(-4) M in the presence and absence of 1.5 MAC halothane, isoflurane or sevoflurane. All three drugs attenuated serotonin-evoked contraction in the coronary artery strips both those strips with and without endothelium (P < 0.05-0.001). However, there were no significant differences in the attenuation of serotonin-induced contraction of the strips, both with and without endothelium, in each drug group. The attenuation potency of halothane was more than that of isoflurane and sevoflurane. The results demonstrate that halothane, isoflurane and sevoflurane attenuate contractile responses evoked by serotonin in bovine epicardial coronary artery both with and without endothelium.

Anesthetics, Inhalation↗