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J Biscoping

Publications and source records attributed to J Biscoping.

At least 19 recordsLinked to original sources
PubMed2000

[Local anesthetics from ester to isomer].

The use of chemical substances to prevent or treat local pain had its origin in South America. It was known that central nervous system stimulation occurred among the natives of Peru who chewed the leaves of an indigenous plant (Erythroxylon coca). Circumoral numbness was believed to have occurred as a by-product of this custom. Attempts to isolate the active principle from these leaves finally resulted in the isolation of the alkaloid, cocaine, by Niemann in 1860. The clinical usefulness of cocaine was not appreciated until 1884, when Koller reported upon topical anesthesia of the eye. The chemical identification of cocaine as a benzoic acid ester led to the synthesis of numerous compounds which were basically benzoic ester derivates. In 1905, Einhorn reported the synthesis of procaine. Tetracaine, the most potent ester of the benzoic acid series appeared in 1930. A major breakthrough in the chemistry of local anesthetic agents occurred in 1943 when Loefgren synthesized lidocaine, since it was not an ester but an amide derivate of diethylamino acetic acid. Concerning structure-activity relationships, local anesthetic agents, in general, possess the chemical arrangement of: aromatic portion--intermediate chain--amine portion. Changes in the aromatic or amine portion of a local anesthetic substance will alter its lipid/water distribution coefficient and its protein-binding characteristics which, in turn, will markedly alter the anesthetic profile. The toxic effects of long-acting local anesthetics on brain and heart, firstly reported by Albright, provided the initial stimulus to develop new amide-type local anesthetics. The first of these drugs, which has come into clinical practice was ropivacaine, the S-enantiomer of two possible optical isomers. It is structurally related to bupivacaine and mepivacaine, exerting a different pharmacodynamic profile, specifically on cardiac electrophysiology (less arrhythmogenic than bupivacaine). Studies on the anesthetic activities and toxicity of the individual enantiomers of bupivacaine and mepivacaine generally indicate, that the S-enantiomers are longer-acting and less toxic than the R-enantiomers.

Anesthetics, Local↗
PubMed2000

[Clinical significance and effects of foreign body embolism during the use of central venous catheters].

An embolism caused by catheters or puncture devices is generally a rare complication during the use of central venous catheters. Possible reasons are either mistakes on the part of the user (e.g. shearing off or tearing of catheters or Seldinger wires) or other accidental causes (e.g. faulty products, material fatigue). As patients are at risk of suffering serious injuries following an embolism, foreign bodies should be removed from the patient's cardio circulatory system as quickly and as completely as possible. Two-dimensional echo-cardiography has proved to be very helpful for diagnostics, while interventional radiology is most effective for the removal of intravascular foreign bodies.

Catheterization, Central Venous↗
PubMed1999

Ropivacaine epidural anesthesia and analgesia versus general anesthesia and intravenous patient-controlled analgesia with morphine in the perioperative management of hip replacement. Ropivacaine Hip Replacement Multicenter Study Group.

UNLABELLED: The aim of our study was to compare epidural anesthesia and analgesia (EDA) with ropivacaine versus general anesthesia followed by IV patient-controlled analgesia with morphine (GA/PCA) after hip replacement regarding pain, side effects, and discharge from the postanesthesia care unit. After ethics committee approval, randomization, and informed consent, 90 patients were enrolled. In Group EDA, epidural anesthesia (ropivacaine 10 mg/mL, 15-25 mL) was followed by an epidural infusion (2 mg/mL, 4-6 mL/h for 24 h, plus top-up doses of 6-10 mL for 48 h). GA/PCA patients received general anesthesia (isoflurane/N2O/fentanyl) followed by IV patient-controlled analgesia with morphine postoperatively. Pain was assessed by using visual analog scales (0-100 mm) at rest and during physiotherapy. Pain at rest was less in the EDA (n = 43) group than in the GA/PCA (n = 45) group (at 10 h: 11.8+/-12.9 vs. 28.4+/-17.1 [P< 0.001]; at 24 h: 14.3+/-11.7 vs. 24.0+/-17 [P<0.01]; in 48 h: 14.3+/-9.3 vs. 21.1+/-17.4 [P = 0.1]). Whereas EDA patients were deemed ready for discharge from the postanesthesia care unit earlier than GA/PCA patients (5.6+/-8.9 vs. 39.7+/-41.5 min), the actual discharge time was comparable. The median time for first passage of flatus was shorter in the EDA group than in the GA/PCA group (26 vs. 47 h). Nausea and vomiting were more common in the GA/PCA group than in the EDA group (16% vs. 28% and 11% vs. 22%, respectively), whereas hypotension (11% vs. 4%) and bradycardia (14% vs. 2%) were less frequent. Under the conditions of the present study, EDA with ropivacaine provided pain control after hip replacement superior to that provided by IV patient-controlled analgesia with morphine, particularly during the first 24 h. Both approaches to pain management were equally safe. IMPLICATIONS: Compared with general anesthesia and postoperative IV patient-controlled analgesia with morphine, epidural anesthesia and analgesia with the new local anesthetic ropivacaine enables patients to be discharged sooner from a postanesthesia care unit and provides superior pain relief during the first 24 h after hip replacement.

Amides↗
PubMed1995

[Mechanical autologous transfusion in orthopedic surgery in children. Is the use of mechanical autologous transfusion possible even in pediatric orthopedic surgical procedures?].

The use of autotransfusion devices is an established method of reducing the need for homologous transfusions in surgery [3, 11, 13], but technical factors still contraindicate the washing and concentration of blood volumes smaller than 300 ml. Therefore, haemoconcentration of small volumes of salvaged blood, as usually found in paediatric surgery, is considered to be a complicated and questionable practice [5]. Whereas these amounts of blood loss are easily tolerated by adults, they may necessitate homologous transfusions in paediatric surgery. In a prospective study, we investigated whether a simple technical modification in the processing of salvaged blood could facilitate the use of autotransfusion devices, especially in children. PATIENTS AND METHODS. Intraoperative blood salvage was performed in children 6 months to 10 years old undergoing surgery for hip dysplasia. Autotransfusion (Dideco STAT) was started when the blood loss was estimated to be more than 20% of the total blood volume (TBV). As a reference, we used a formula based on body weight [10]: for children up to the age of 6 years 80 ml/kg blood volume and for children up to 10 years 75 ml/kg. The total volume of salvaged fluid including blood, anticoagulant solution, and surgical irrigation was collected in a reservoir and transferred to the autotransfusion set, after which the reservoir was rinsed with 500 ml 0.9% saline solution in order to save the remaining blood. After processing, the blood was stored in the retransfusion bag. By adding the same volume of plasma expander (6% hydroxyethyl starch [HES], molecular weight 450,000), spontaneous sedimentation of the washed autologous erythrocytes (RBCs) for 10-15 min led to a concentrate of RBCs. After 10 mu filtration, the RBC suspension was retransfused (Figs. 1-3). RESULTS. Within 12 months, autotransfusion was performed during 6 out of 15 surgical procedures according to the method described above. The calculated blood loss averaged 25.6% of TBV, of which 21.4% (= 272 ml) could be processed by the autotransfusion device (Table 3). The mean values of 2.6 g/dl haemoglobin (Hb) and 6.8% haematocrit (HCt) in the salvaged blood increased to 9.4 g/dl and 27.3% in the processed RBC concentrates. After adding 6% HES solution, spontaneous sedimentation of the RBCs led to values of Hb 22.1 g/dl and HCt 59.8%. An average of 59.5 ml (22-99 ml) sedimented RBCs was retransfused to the patients, including 11.6 ml 6% HES solution (Table 4). In this manner, the need for homologous transfusions could be avoided in these patients both during and after surgery. CONCLUSIONS. This study shows that the use of blood salvaging in paediatric surgery is indicated under certain conditions. With the aid of the simple modification described above, we solved the main problem in paediatric autotransfusion by concentrating RBC suspensions with low Hb and Hct values after using the autotransfusion device.

Blood Sedimentation↗
PubMed1994

Development of resistance by Enterobacter cloacae during therapy of pulmonary infections in intensive care patients.

The emergence of resistance during therapy and the efficacy of different antibiotic therapy regimens were studied in 38 intensive care patients suffering from pulmonary infections caused by Enterobacter cloacae. Every three days a fresh isolate was obtained from each patient and tested in vitro for susceptibility to 16 antibiotics by determination of the minimal inhibitory concentrations. During therapy with cefotaxime and tobramycin the E. cloacae strains from 47% of the patients became resistant to cefotaxime within 6 days. In all cases resistance encompassed all other broad-spectrum penicillins and cephalosporins tested, as well as aztreonam. Development of resistance regularly led to persistence of bacteria. Resistance to tobramycin, ciprofloxacin or imipenem was not observed. Treatment of 25 patients with persisting E. cloacae infections was successful in 17 out of 18 patients treated with imipenem and in 6 out of 7 patients receiving ciprofloxacin.

Adolescent↗
PubMed1993

Intercostal nerve block, interpleural analgesia, thoracic epidural block or systemic opioid application for pain relief after thoracotomy?

The purpose of this study was to investigate the effect of different pain-relief methods (regional and systemic) following thoracotomies on the cardiovascular system, pulmonary gas exchange, various endocrine parameters and subjective perception. A further aspect was to evaluate the benefits of interpleural analgesia as a new regional technique against already established regional techniques, such as intercostal nerve block and thoracic epidural block. All postoperative pain methods led to a significant time-dependent reduction of the adrenaline concentrations in plasma while the noradrenaline concentrations did not change significantly. There were no statistical differences in catecholamine concentrations among the different study groups, although the mean concentrations of adrenaline in patients having a thoracic epidural block for pain relief were lower in comparison to the findings in other groups. The plasma concentrations of the "stress metabolites", such as glucose, free fatty acids and lactate, as well as the haemodynamic (mean arterial pressure, heart rate) and pulmonary parameters (blood gas analyses), showed no significant differences among groups. In contrast to the other pain-relieving methods, interpleural analgesia did not lead to sufficient pain relief in that 7 out of 10 patients needed supplementary systemic opioid therapy. Therefore, interpleural analgesia for pain relief following thoracotomies cannot be recommended.

Adrenocorticotropic Hormone↗
PubMed1993

[Intravenous regional anesthesia of the arm].

Intravenous regional anesthesia is a well established technique since the start of this century. It is easy to perform, with rapid onset of analgesia and safe to practice, when proper patient monitoring (ECG, intermittent blood pressure monitoring, oxygen delivery by nasal insufflation) is established and a local anesthetic solution with low systemic toxicity (e.g. prilocaine) is used. When choosing this technique of regional anesthesia it is an important condition, that the operative procedure has to be finished before the tourniquet of the upper arm is released. Immediately after this cuff-release and recirculation of the arm analgesia will diminish. When using prilocaine or mepivacaine as local anesthetic drug a complete surgical analgesia of 30 up to 45 min can be achieved. Long-acting local anesthetics should not be used because of their increased systemic toxicity under the aspect of drug wash-out at the end of the procedure or in terms of inadvertent cuff release. The site of action of intravenous regional anesthesia has been controversial, since adequate clinical investigations with contrast media and radio isotopes proved, that the principal site of action is at the peripheral nerve endings.

Anesthesia, Conduction↗
PubMed1992

Plasma prilocaine and mepivacaine concentrations after combined lumbosacral plexus block.

In a pharmacokinetic study of combined sciatic/3-in-1 block for lower limb surgery, the two moderate-acting local anaesthetics prilocaine and mepivacaine were compared. The mean maximum venous plasma concentrations of mepivacaine were more than twice as high as when prilocaine was used as anaesthetic (5.1 micrograms/ml vs. 2.37 micrograms/ml). When used in combination with the former, ornipressin did not reduce plasma concentrations of mepivacaine to values which were below the threshold for toxic symptoms (5-6 mg/ml). The peak plasma concentrations exceeded the threshold of 5 micrograms/ml in four of the nine patients of the mepivacaine group (maximum value 7.21 mg/ml) and in two of the nine patients of the mepivacaine+ornipressin group (maximum value 8.61 micrograms/ml).

Adult↗
PubMed1991

[Fetal methemoglobinemia caused by prilocaine--is use of prilocaine for pudendal block still justified?].

17 women received 2 x 10 ml prilocaine 1% as a pudendal block sub partu. At delivery, the foetomaternal distribution ratio of the local anaesthetic was evaluated and the development of Met-Hb-concentration in the neonate was measured up to six hours post partum. The Met-Hb-concentration in the neonate was relatively low with a maximum of 1.8% after two hours, followed by a steady decline. A probable explanation for the Met-Hb-concentration could be the unexpected low foetomaternal ratio of distribution (0.5) and the increased renal elimination of the amide-type local anaesthetic in the neonate, respectively. According to these results, no contraindication for prilocaine in pudendal block is indicated.

Administration, Intravaginal↗
PubMed1991

[Pharmacokinetics and pharmacodynamics of local anesthetics].

In clinical practice the efficacy of local anaesthesia is judged by the time of onset, duration and the quality of sensory and motor blockade. Apart from the physicochemical properties of local anaesthetics, a sufficient blockade depends on the volume and the concentration which are applied. Generally increasing the dose leads to a better quality of blockade as well as a higher risk of toxicity. This dilemma is evident in procedures, where, due to continuous or repetitive application within one day, the applied total dosage exceeds the recommended maximum limit. The values regarding maximum doses published in the German Pharmacopeia ("Rote Liste") can be defined as being more or less the product of the volume of distribution and the toxic concentration in the plasma. According to that formula the maintainance doses for continuous techniques in regional anaesthesia are derived from the product of the elimination half-life and the toxic plasma concentration. The values for toxic plasma concentrations are difficult to define since only the free protein-unbound fraction of a local anaesthetic is responsible for undesired side-effects. This fraction can be influenced by acidosis, body temperature and shortage of specific binding protein. Some well documented case reports show that another major cause of acute toxicity is nearly always due to inadvertent intravascular injections. This event can occur nearly unnoticed and leads to life-threatening complications even with lower doses than the recommended maximum doses. Only the application of high concentrations into well vascularised regions is followed by a similarly quick development of high plasma levels. Typical kinetics of local anaesthetics are presented for various methods of regional anaesthesia informing the anaesthetist on corresponding plasma concentrations if the recommended maximum doses are exceeded and thus he gets useful information for his daily work.

Anesthesia, Conduction↗
PubMed1991

[Ultrafiltration as a fast and simple method for determination of free and protein bound prilocaine concentration. Clinical study following high-dose plexus anesthesia].

Ultrafiltration as a Fast and Simple Method to Separate Free and Protein Bound Concentrations of Local Anesthetics/Pharmacokinetic studies following high-dose anesthesia of the axillary plexus. As many other drugs amide-type local anesthetics are protein bound in plasma. The extent of binding varies between local anesthetics. The free, non protein-bound fraction of these drugs is mainly responsible for cardiovascular and central-nervous side effects. If high doses are necessary for regional anesthetic procedures it seems reasonable to determine the pharmacological active, non protein-bound fraction in addition to the total concentration of the local anesthetic drug. Analyses of protein binding was performed using an ultrafiltration method which is discussed in this paper. Total (HPLC) and unbound plasma levels (combination of ultrafiltration and HPLC) of the local anesthetic drug in central venous blood were studied in 20 healthy orthopedic patients, undergoing plastic surgery of the upper limb (elbow, forearm, hand), over a time period of 90 min, when performing axillary plexus block with 30 ml prilocaine (CAS 721-50-6) 2% (= 600 mg). Separation of the local anesthetic fractions was achieved using the ultrafiltration system MPS-1, equipped with a YMT-membrane. These membranes have a narrow pore size retaining molecules larger than 30000 Dalton. Ultrafiltration was accomplished by subjecting 1.2 ml of plasma to centrifugation at 2000 x g for 60 min at 30 degrees C using a clinical centrifuge equipped with a 35 degree angle head rotor. The plasma samples were adjusted to physiological pH (7.40) with a sodium-potassium-phosphate buffer. The tightness of the used membrane was controlled by a micromethod for protein estimation (sensitivity 10 micrograms/ml).(ABSTRACT TRUNCATED AT 250 WORDS)

Blood Proteins↗
PubMed1991

[Is the plasma protein binding of lidocaine modified by the simultaneous administration of midazolam?].

Perioperative antiarrhythmic therapy with lidocaine (bolus dosage 100 mg followed by infusion of 200 mg/h) was performed in 24 patients; 12 of them simultaneously received an intravenous injection of 10 mg midazolam with the bolus of lidocaine (group I: with midazolam; group II: without midazolam). Central venous blood samples were collected over a period of 1 h (1, 3, 5, 10, 20, 30, and 60 min after the bolus) to evaluate unbound and total (protein-bound + unbound) plasma concentrations of lidocaine, thus calculating plasma protein binding. One minute after intravenous administration of lidocaine peak plasma concentrations occurred: in group I 5.38 +/- 1.99 micrograms/ml (mean +/- SD), in group II 5.25 +/- 1.90. Up to 60 min there was only a gradual decrease in plasma concentrations in both groups. There was no significant difference between the two groups (group I: mean free concentration 0.67-0.80 micrograms/ml; mean total concentration 4.84-5.38 micrograms/ml; mean plasma protein binding 83%-86%; group II: 0.69-0.89 micrograms/ml; 4.62-5.25 micrograms/ml; 82%-85%). We draw the conclusion that midazolam administration is safe in patients undergoing antiarrhythmic therapy or regional anesthesia with lidocaine.

Adult↗