Biomedical subjects
R Bartkowski
Publications and source records attributed to R Bartkowski.
[Diagnostic related groups. DRG practice].
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Evaluation of neuromuscular and cardiovascular effects of two doses of rapacuronium (ORG 9487) versus mivacurium and succinylcholine.
BACKGROUND: This study compares the neuromuscular blocking and cardiovascular effects of rapacuronium (ORG 9487), a new aminosteroid nondepolarizing muscle relaxant, to recommended intubating doses of succinylcholine and mivacurium. METHODS: Adult patients were randomized in an open-label fashion to receive 1-5 microg/kg fentanyl before 1.5 mg/kg propofol induction followed by 1.5 or 2.5 mg/kg rapacuronium, 1.0 mg/kg succinylcholine, or 0.25 mg/kg mivacurium (i.e., 0.15 mg/kg followed by 0.1 mg/kg 30 s later). RESULTS: Patient neuromuscular blockade status was monitored by measuring the train-of-four response to a supramaximal stimulus at the ulnar nerve every 12 s. Percentage of the first twitch of the train-of-four (T1) at 60 s was similar in patients receiving 1.5 mg/kg rapacuronium, 2.5 mg/kg rapacuronium, and succinylcholine and was significantly less than in patients in the mivacurium group (26, 16, and 18%, respectively, vs. 48%; P < 0.01). Times to 80% T1 depression were also similar among patients in the 1.5 mg/kg rapacuronium, 2.5 mg/kg rapacuronium, and succinylcholine groups and significantly longer in the mivacurium group (62, 54, and 54 s, respectively, vs. 112 s; P < 0.01). Clinical duration was longer in all groups compared with the succinylcholine group; however, clinical duration in the 1.5 mg/kg rapacuronium group was shorter compared with the mivacurium group (15 vs. 21 min, respectively; P < 0.01). Heart rate changes were mild in the 1.5 mg/kg rapacuronium, succinylcholine, and mivacurium groups. The patients in the 2.5 mg/kg rapacuronium group had significantly higher heart rates compared with patients in the mivacurium group. No differences were found in blood pressure changes among patients in the four groups. CONCLUSIONS: Rapacuronium, 1.5 and 2.5 mg/kg, produced neuromuscular blockade as rapidly as succinylcholine and significantly faster than mivacurium. Although succinylcholine continued to show the shortest duration, 1.5 mg/kg rapacuronium used a rapid onset and a relatively short duration and may be considered an alternative to succinylcholine.
Chemo-embolization of experimental liver metastases. Part I: distribution of biodegradable microspheres of different sizes in an animal model for the locoregional therapy.
An experimental in vivo rat model was established to simulate the embolization therapy of non-resectable liver metastases with microparticulate systems. The effects of biodegradable microspheres on a transplanted liver-tumor cell line in rat livers were investigated with respect to particle size. The distribution of fluorescence-labelled microspheres was investigated to characterize the effects of long-term embolization with biodegradable microspheres, and the suitability and relevance of this animal model. Novikoff hepatoma cells were implanted into the central liver lobe of Sprague-Dawley rats. After seven days, four batches of fluorescence-marked microspheres (17 microm, 25 microm, 30 microm, and 40 microm) were administered into the proper hepatic artery. Liver(including the tumor), lung and spleen were isolated and frozen sections and tissue cubes of liver-, border-, and tumor tissue were prepared. The sections were examined by fluorescence microscopy. The cubes were extracted and the fluorescence of the marker quantified. During operation, microspheres smaller than 40 microm did not cause complete embolization. The slides showed the spreading of the smaller particles to the spleen and lung. Only 40 microm particles accumulated in the liver and were rarely detectable in other organs. The extraction showed a high concentration of the 40 microm particles in the border tissue. Apparently they were trapped proximal to the tumor capillary system and therefore showed a high ratio of border/tumor concentration. Microparticles smaller than 40 microm had a border/tumor concentration ratio of less than one and were distributed to the spleen and lung. In conclusion, a mean particle diameter of at least 40 microm is required for embolization. Thus, the model shows similarity to clinical situations in the treatment of human liver tumor and metastases.
[Initial experiences with interposition of a silicon sheet in reconstruction of the wrist joint].
We report about the possibility to improve the condition of incongruent joint surfaces by temporary interposition of silicon sheet in the radiocarpal joint. The implant was used in 18 patients with damaged joint surfaces, either for the primary operation or for revision. It was removed four to six weeks after having started physiotherapy. Our results show that this procedure can improve the condition of joint surfaces. Silicon-induced granulation tissue can even uprough parts of the joint surface and thus reduce chondral friction. We did not see any complications.
[Use of the ICPM surgical key: initial experiences in routine clinical documentation and reimbursement calculation].
The German version of the International Classification of Procedures in Medicine (ICPM) [3] is used in the Department of General Surgery of Göttingen University since 1995. There is full compatibility with the official catalogue of operations (OPS-301) [4] for administrative purpose combined with a more sophisticated medical classification. The ICPM may become a reference system for scientific evaluations of surgical treatment [1].
Efficacy and safety of divided dose administration of mivacurium for a 90-second tracheal intubation.
STUDY OBJECTIVE: To compare the safety and effectiveness of 0.25 mg divided doses of mivacurium chloride to succinylcholine for a 90-second tracheal intubation. DESIGN: Randomized, double-blind, multicenter study in two groups. SETTING: Operating rooms at four university medical centers. PATIENTS: 200 healthy ASA status I and II adult patients scheduled for elective surgery with general anesthesia and endotracheal intubation. INTERVENTIONS: Patients were premedicated with 1 to 2 mg midazolam and 2 micrograms/kg fentanyl. Anesthesia was induced with 2 mg/kg propofol. Group A received 0.25 mg/kg mivacurium given as a divided dose (0.15 mg/kg followed in 30 seconds with 0.1 mg/kg). Group B (control) received 1.5 mg/kg succinylcholine (SCh) preceded two minutes earlier by 50 micrograms/kg d-tubocurarine (dtc). MEASUREMENTS AND MAIN RESULTS: Tracheal intubation grading, train-of-four response of the adductor pollicis, heart rate (HR), and mean arterial blood pressure (MAP) were measured and evaluated. Chi-square analysis was performed for comparison between Group A and Group B with respect to the frequency distribution of intubation using the scores excellent, good, and poor and not possible (combined). Group B had a significantly higher excellent score of intubation than Group A, 84% versus 56% (p < 0.0001). No significant difference was found between the two groups when the scores excellent and good were combined (Fisher's Exact test, p = 0.28). The changes in MAP and HR were similar for the two groups. CONCLUSIONS: When Sch is not desirable, mivacurium 0.25 mg/kg given as a divided dose provides good to excellent intubation conditions 90 seconds after the initial dose without significant changes in MAP or HR. It can be an appropriate alternative for short surgical procedures. It must be emphasized that this conclusion does not apply to rapid-sequence induction-intubation.
[Intraoperative cholangiography and anterograde bile duct exploration in laparoscopic cholecystectomy--technique, results, perspectives].
The avoidance of (unrecognized) bile duct injuries (1) and the management of bile duct stones (pre-, intra- or postoperatively?) (2) are believed to be the main problems in laparoscopic cholecystectomy (LCE) at present. They must be a challenge for surgery to develop and improve the concepts of minimally invasive therapy for treatment of cholelithiasis. Intraoperative cholangiography (IOC) plays a very important role and is the basis of innovative, laparoscopically assisted procedures (3) for single session therapy of gallbladder and bile duct stones. (1) A detailed analysis of the literature proves the value of IOC for avoidance or early recognition of iatrogenic bile duct injuries. IOC is of most importance to compensate fundamental restrictions of the laparoscopic technique (missing possibility for palpation or anterograde preparation). IOC adds additional safety to the laparoscopic procedure and detects unsuspected bile duct stones. (2) At present, surgical management of cholecysto-/choledocholithiasis is split in two independent procedures: LCE and pre- or postoperative endoscopic retrograde cholangiography (ERC) with optional endoscopic papillotomy (EPT). A critical analysis of the literature and of the results of 623 LCE performed between 10/91 and 9/93 in the own institution leads to the following conclusions: Preoperative ERCs are performed unnecessary in about 50% of cases. They could be avoided by routine use of IOC. The combination of two independent procedures (LCE and ERC/PT) for treatment of cholelithiasis increases mortality and morbidity. Thus, the outcome of "therapeutic splitting" is not clearly superior to conventional treatment by open surgery.2+ common bile duct exploration allows final diagnosis and treatment in a single session. Additional risks and costs caused by choledochotomy as well as by pre- or post-operative endoscopic retrograde procedures (ERC, EPT) are avoided.(ABSTRACT TRUNCATED AT 250 WORDS)
Influence of different methods of vagotomies on the secretion of cholecystokinin in dogs.
In six dogs, a selective proximal vagotomy, gastric vagotomy, and truncal vagotomy were performed successively. Basal and postprandial cholecystokinin (CCK) concentrations in the peripheral blood were measured by radioimmunoassay. After all the different types of vagotomy, especially after truncal vagotomy, an increased postprandial secretion of CCK was found compared with the healthy animal. Possible causes discussed are the cutting of vagal fibers, which might inhibit the secretion of CCK cells, and the changed gastric and pancreatic secretion.
Should the gas outlet port on membrane oxygenators be routinely scavenged during cardiopulmonary bypass?
Elimination of a volatile anesthetic agent administered prior to the start of bypass through the oxygenator has not been previously described. The purpose of this study was to determine the contamination risk from enflurane used before but not during cardiopulmonary bypass. Enflurane concentration was measured from the gas outlet port of a membrane oxygenator using infrared gas analysis in 11 cardiac surgical patients. The mean peak concentration at the gas outlet port in patients who had a final end-tidal concentration of < or = 0.3% was 0.08 +/- 0.04%, compared to 0.18 +/- 0.05% in patients with a final end-tidal concentration of more than 0.3%, P < 0.001. The elapsed time to reach peak concentration was 8.3 +/- 8.4 minutes, whereas the elapsed time from the peak concentration to 50% of the peak level was 63.1 +/- 25.1 minutes. At the time of peak enflurane release, a concentration of less than 2 ppm was measured at distances of 10 cm or less from the oxygenator gas outlet port in patients with an end-tidal enflurane of < or = 0.3%. In one patient with a final end-tidal enflurane of 1.1%, a contaminant level of 2 ppm could be measured at 95 cm from the oxygenator gas outlet port. This demonstrates that there is a potential risk of contamination from volatile anesthetics used immediately prior to extracorporeal circulation. Minimizing this risk may necessitate routine scavenging of the oxygenator, or simply avoiding increased concentrations of inhalation anesthesia before initiating cardiopulmonary bypass.
[Splenogonadal fusion].
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Hepatic arterial infusion (HAI) chemotherapy proves to be advantageous in the treatment of experimental liver tumors.
To evaluate the best locoregional approach in the treatment of hepatic tumors we investigated four different treatment modalities. Sixty female Sprague-Dawley rats were randomized to the following treatment groups: (1) untreated control; (2) hepatic artery ligation; (3) hepatic artery ligation plus portal 5-FU chemotherapy; (4) arterial 5-FU chemotherapy; (5) portal 5-FU chemotherapy. All animals received Novikoff hepatoma cells inoculated in the median liver lobe. After tumor inoculation animals were treated according to their randomization and surgery was performed for repeated tumor size measurements. Through hepatic artery ligation, hepatic artery ligation plus portal 5-FU infusion as well as through arterial 5-FU infusion a significant tumor growth inhibition compared to the untreated control could be achieved. The portal infusion group even showed an accelerated tumor growth; however, this effect was not significant. We conclude that the intraarterial application in terms of clinical feasibility and duration of response should be the preferred approach in locoregional therapy of liver malignancies.
Numerical and experimental study of steady-state CO2 and inert gas washout.
The predictions of a single-path trumpet-bell numerical model of steady-state CO2 and infused He and sulfur hexafluoride (SF6) washout were compared with experimental measurements on healthy human volunteers. The mathematical model used was a numerical solution of the classic airway convention-diffusion equation with the addition of a distributed source term at the alveolar end. In the human studies, a static sampling technique was used to measure the exhaled concentrations and phase III slopes of CO2, He, and SF6 during the intravenous infusion of saline saturated with a mixture of the two inert gases. We found good agreement between the experimentally determined normalized slopes (phase III slope divided by mixed expired concentration) and the numerically determined normalized slopes in the model with no free parameters other than the physiological ones of upper airway dead space, tidal volume, breathing frequency, and breathing pattern (sinusoidal). We conclude 1) that the single-path (Weibel) trumpet-bell anatomic model used in conjunction with the airway convection-diffusion equation with a distributed source term is adequate to describe the steady-state lung washout of CO2 and infused He and SF6 in normal lungs and 2) that the interfacial area separating the tidal volume fron from the functional residual capacity gas, through which gas diffusion into the moving tidal volume occurs, exerts a major effect on the normalized slopes of phase III.
Feasible model for locoregional and systemic longterm administration of drugs and concomitant blood sampling in Sprague-Dawley rats.
This methodological study describes three surgical procedures for locoregional and systemic drug administration, which are based on a similar experimental design. Cannulation of the arterial and portal access to the liver in comparison to the general venous system, and arterial access to the large intestine through a permanently implantable system, suitable for serial bolus injections and infusions in unrestrained rats, is presented (experiment I). Furthermore, an infusion system for longterm administration (experiment II) and a method for blood sampling during locoregional or systemic infusion procedures (experiment III) have been developed. The positioning and free flow of the catheters were checked by means of scintigraphy, administration of fluorescein under UV light and angiography in animals of experimental series I. After 7 days, no obstruction was detected. On day 15 and 30 following implantation 73.3% and 58.3% of the animals, respectively, showed unimpeded flow through the catheter system. The methods described here were well tolerated by the animals without alteration of their general condition and are currently in use in a series of chemotherapeutic and pharmacokinetic investigations.
Experiments on the toxicity of locoregional liver chemotherapy with 5-fluoro-2'-deoxyuridine and 5-fluorouracil in an animal model.
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Experiments on the efficacy and toxicity of locoregional chemotherapy of liver tumors with 5-fluoro-2'-deoxyuridine (FUDR) and 5-fluorouracil (5-FU) in an animal model.
For the investigation of locoregional chemotherapy of liver neoplasms we developed a standardized animal model in the rat. Continuous infusion therapy or repeated bolus injections of FUDR or 5-FU were given via the hepatic artery, the portal vein or the vena cava in tumor-bearing animals. The efficacy of the treatment was determined by measuring the tumor volume 3 weeks after tumor cell implantation. For the evaluation of the local and systemic toxicity serum GOT, GPT, and total bilirubin were determined. DNA single strand breaks were assessed in isolated liver and bone marrow cells. Inhibition of colony formation of bone marrow stem cells was determined by CFU-C and CFU-S bioassay. A significant reduction of tumor growth was observed only after continuous infusion of FUDR via the hepatic artery. Systemic toxicity was lowest in this group for both compounds while the local liver toxicity was only slightly elevated.