[New perspectives in laparoscopic simulation: from students' skills lab to stress evaluation]. / Neue Perspektiven der laparoskopischen Simulation: Vom Studententrainingslabor bis zur Stressevaluation.

BACKGROUND: Application of a LapSim-training model in the Students' Skills Lab as well as the objective evaluation of stress in a virtual operating room scenario offer new perspectives in laparoscopic simulation. METHODS: In a Students' Skills Lab , assessment of learning curves of laparoscopic basic skills and complex tasks was carried out with 28 individuals at a LapSim Virtual Reality (VR)-simulator in a training curriculum consisting of 9 units. In addition, in a virtual operating room scenario, stress evaluation was performed with 18 surgeons by means of a sympathicograph and, in that way, the laparoscopic error and complication rate were recorded. Three different stress reactions (SR 1-3) could be identified. RESULTS: In the Students' Skills Lab, at the beginning of the curriculum (unit 1), the best learning effects together with the improvement of the laparoscopic performance could be presented for the two parameters: Extent of movement of the laparoscopic instruments (length of path as well as degree of deviation from the "optimal course") and duration of the procedure. In the virtual stress scenario, the intraoperative error rate of surgeons with a stress reaction without recovery (SR-1) was lower than of those with recovery (SR-2) or without stress reaction (SR-3). CONCLUSION: Application of the LapSim Virtual Reality (VR)-simulator in the Students' Skills Lab and for stress and crisis simulation represents a new perspective in laparoscopic simulation, which will have to be further evaluated in the future. The transfer to the "real" operating room will have to be continued as a training and scientific validation paradigm.

Three different types of surgeon-specific stress reactions identified by laparoscopic simulation in a virtual scenario.

BACKGROUND: Minimally invasive surgery causes higher mental strain for surgeons than conventional surgery and is significantly more stressful in consecutive cases. This study aimed to investigate whether individual stress responses are associated with intraoperative alterations of manual surgical skills and technical errors of the laparoscopic surgeon. METHODS: The LapSim virtual reality simulator was used. Stress measurement was carried out for 18 surgeons performing a virtual cholecystectomy using the LapSim simulator in the context of the patient simulator provided by the METI Corporation. In the course of the study, the surgeons were exposed to different external stressors (S1-S4) in defined intervals. The activity of the sympathetic nervous system was evaluated by skin resistance with the help of a sympathicograph. RESULTS: Three different surgeon-specific stress reactions (SSR) could be identified. The first, SSR-1, with significant stress reactions during the study without recovery, showed larger laparoscopic extensions of movement but fewer intraoperative complications than SSR-2 (recovery after the stress reactions) or SSR-3 (without significant stress reactions). CONCLUSIONS: The mental load of the laparoscopic surgeon might be highly optimized by continuous activity of the sympathetic nervous system. The question of what extent or quality of stress produces adverse effects remains unclear.

[Combined simulation training: a new concept and workshop is useful for crisis management in gastrointestinal endoscopy]. / Kombiniertes Simulationstraining: Ein neues Kurskonzept trainiert und verbessert das Krisenmanagement der gastroenterologischen Endoskopie.

INTRODUCTION: Crisis management as well as realistic emergency situations can be trained in the new developed simulation workshop "Gastrointestinal Endoscopy and Crisis Resource Management" by combining a full-scale simulator and the Erlanger Endoscopy Trainer. The aim of the current study was to evaluate the efficiency of the newly developed simulation workshop. METHODS: Endoscopists with more than 12 months experience can train their endoscopic skills and crisis resource management with the help of different simulators. In addition, two different scenarios (GI bleeding with significant blood loss and sedation overdoses) embedded in a realistic surrounding (emergency room) have to be managed by the participants. Vital parameters, endoscopic skills, as well as personal interactions were recorded and graded. RESULTS: 100 participants took part in the newly developed workshop (between June and December 2003). The participants showed a significantly better endoscopic performance and a significantly better crisis management after the standardized training program. CONCLUSIONS: Simulation training plays an essential role in aviation and minimizes the risk for human errors. In the current study it is clearly shown that simulation training is also useful in gastrointestinal endoscopy. The newly developed workshop may thus be of crucial importance to improve personal crisis management. Simulation also leads to an improvement of endoscopic and emergency skills. Accordingly, simulation training should be recommended or offered as an education option in gastrointestinal endoscopy.

Initial evaluation of a shoulder arthroscopy simulator: establishing construct validity.

Formal evaluation of surgical simulators is essential before their introduction into training programs. We report our assessment of the Mentice Corp Procedicus shoulder arthroscopy simulator. This study tests the hypothesis of construct validity that experienced surgeons will score better on the simulator than individuals with minimal to no experience with the technique. Thirty-five subjects were stratified into three groups (novice, intermediate, and expert) based on their past 5 years' experience with shoulder arthroscopies. Each subject had an identical session on the simulator and completed anatomic identification, hook manipulations, and scope navigation exercises. We found statistically significant differences among the three groups in hook manipulation and scope navigation exercises, with the expert group performing the exercises more quickly (P =.013) and more accurately (P =.002) than the other two groups. No statistically significant differences were found among the groups in the identification of anatomic landmarks. Experts rated the simulator as an effective teaching tool, giving it a mean score of 4.22 and 4.44 (maximum, 5) for teaching instrument control and triangulation, respectively.

Simulated medical learning environments on the Internet.

Learning anatomy and surgical procedures requires both a conceptual understanding of three-dimensional anatomy and a hands-on manipulation of tools and tissue. Such virtual resources are not available widely, are expensive, and may be culturally disallowed. Simulation technology, using high-performance computers and graphics, permits realistic real-time display of anatomy. Haptics technology supports the ability to probe and feel this virtual anatomy through the use of virtual tools. The Internet permits world-wide access to resources. We have brought together high-performance servers and high-bandwidth communication using the Next Generation Internet and complex bimanual haptics to simulate a tool-based learning environment for wide use. This article presents the technologic basis of this environment and some evaluation of its use in the gross anatomy course at Stanford University.

Simulated learning environments in anatomy and surgery delivered via the next generation internet.

The Next Generation Internet (NGI) will provide high bandwidth, guaranteed Quality of Service, collaboration and security, features that are not available in today's Internet. Applications that take advantage of these features will need to build them into their pedagogic requirements. We present the Anatomy Workbench and the Surgery Workbench, two applications that require most of these features of the NGI. We used pedagogic need and NGI features to define a set of applications that would be difficult to operate on the current Internet, and that would require the features of the NGI. These applications require rich graphics and visualization, and extensive haptic interaction with biomechanical models that represent bony and soft tissue. We are in the process of implementing these applications, and some examples are presented here. An additional feature that we required was that the applications be scalable such that they could run on either on a low-end desktop device with minimal manipulation tools or on a fully outfitted high-end graphic computer with a realistic set of surgical tools. The Anatomy and Surgery Workbenches will be used to test the features of the NGI, and to show the importance of these new features for innovative educational applications.

G2H--graphics-to-haptic virtual environment development tool for PC's.

For surgical training and preparations, the existing surgical virtual environments have shown great improvement. However, these improvements are more in the visual aspect. The incorporation of haptics into virtual reality base surgical simulations would enhance the sense of realism greatly. To aid in the development of the haptic surgical virtual environment we have created a graphics to haptic, G2H, virtual environment developer tool. G2H transforms graphical virtual environments (created or imported) to haptic virtual environments without programming. The G2H capability has been demonstrated using the complex 3D pelvic model of Lucy 2.0, the Stanford Visible Female. The pelvis was made haptic using G2H without any further programming effort.

Successful treatment of a patient with ARDS after pneumonectomy using high-frequency oscillatory ventilation.

High frequency oscillatory ventilation (HFOV) was used in a patient who developed the acute respiratory distress syndrome 5 days following a right pneumonectomy for bronchogenic carcinoma. When conventional pressure-controlled ventilation failed to maintain adequate oxygenation, HFOV dramatically improved oxygenation within the first few hours of therapy. Pulmonary function and gas exchange recovered during a 10-day period of HFOV. No negative side effects were observed. Early use of HFOV may be a beneficial ventilation strategy for adults with acute pulmonary failure, even in the postoperative period after lung resection.

Computed tomography-based tracheobronchial image reconstruction allows selection of the individually appropriate double-lumen tube size.

OBJECTIVES: To determine whether individualized selection of double-lumen tubes or alternatives based on three-dimensional reconstruction of the tracheobronchial image from routine preoperative computed tomography (CT) scans leads to clinically appropriate choices. DESIGN: Prospective observational study; comparison to historic controls. SETTING: Anesthesia and radiology facilities of a university medical center. PARTICIPANTS: Forty-nine patients undergoing thoracic surgery requiring one-lung ventilation. INTERVENTIONS: Three-dimensional image reconstruction of individual tracheobronchial anatomy was performed from routine preoperative spiral CT scans as well as from scans of five left-sided and four right-sided double-lumen tubes. Results of image-based tube size selection were compared with literature recommendations. Prospectively, individualized tube selection was performed by superimposition of printed transparencies of tubes over the tracheobronchial system and was validated using bronchoscopic and clinical criteria (n = 24). MEASUREMENTS AND MAIN RESULTS: Three-dimensional reconstruction visualized individual anatomy with good accuracy and resolution. Correlations between patient morphology and tracheobronchial dimensions were weak (height versus mainstem bronchial diameters: r < 0.50). In 11 of 48 patients (23%). CT-fitted double-lumen tube sizes would have differed from a conventional height-based and gender-based selection. Individual, prospective, CT-based double-lumen tube selection was associated with (1) good fit and positioning confirmed by fiberoptic bronchoscopy, (2) adequate bronchial cuff seal volumes, (3) complete lung separation, and (4) oxygenation and ventilation parameters during one-lung ventilation similar to those with conventional size selection. In one patient, three-dimensional CT study allowed noninvasive evaluation of a tracheal stenosis precluding double-lumen tube placement. CONCLUSION: Individualized selection of double-lumen tube size using CT-based reconstructions of tracheobronchial anatomy leads to clinically appropriate choices. Risks resulting from variations in tracheobronchial morphology are recognized in advance.

Virtual reality and women's health: a breast biopsy system.

Minimally invasive procedures are becoming much more common in surgical practice because of the many advantages for patient comfort and convenience, and improved surgical access. However some of the major problems leading to occasional surgical errors with this minimal access method are restricted vision, limited sense of touch, difficulties in identification in 3D space of the position of the instrument tips, and their handling during delicate, short-distance movements toward the surgical target area. These factors emphasize the need for computer simulated training in surgical manipulations and procedures in preparation for conducting them in patients. The key new feature of our proof-of-concept training simulator is a preventive mechanism that serves at least two functions. As the surgical target (or a critical structure) is approached, a haptically generated preventive force forewarns the surgeon, making it possible to abort those maneuvers that may lead to adverse results. By announcing a potential collision of a virtual instrument tip with a surgical target, the time used for searching for the target is shortened, and the haptic signal minimizes the potential of tissue damage. This real-time, interactive, virtual reality based, haptic breast biopsy-training simulation is a PC/NT based multitasking, multithreading system. It is based upon an advanced force feedback device. The system monitors and indirectly guides the surgeon's movements, while providing high fidelity visual and force feedback cues as the area of surgical interest is approached. Our first application is with human breast.

Adaptive lung ventilation (ALV) during anesthesia for pulmonary surgery: automatic response to transitions to and from one-lung ventilation.

UNLABELLED: Adaptive lung ventilation is a novel closed-loop-controlled ventilation system. Based upon instantaneous breath-to-breath analyses, the ALV controller adjusts ventilation patterns automatically to momentary respiratory mechanics. Its goal is to provide a preset alveolar ventilation (V'A) and, at the same time, minimize the work of breathing. Aims of our study were (1) to investigate changes in respiratory mechanics during transition to and from one-lung ventilation (OLV), (2) to describe the automated adaptation of the ventilatory pattern. METHODS: With institutional approval and informed consent, 9 patients (33-72 y, 66-88 kg) underwent ALV during total intravenous anesthesia for pulmonary surgery. The ALV controller uses a pressure controlled ventilation mode. V'A is preset by the anesthesiologist. Flow, pressure, and CO2 are continuously measured at the DLT connector. The signals were read into a IBM compatible PC and processed using a linear one-compartment model of the lung to calculate breath-by-breath resistance (R), compliance (C), respiratory time constant (TC), serial dead space (VdS) and V'A. Based upon the results, the controller optimizes respiratory rate (RR) and tidal volume (VT) such as to achieve the preset V'A with the minimum work of breathing. In addition to V'A, only PEEP and FIO2 settings are at the anesthesiologist's discretion. All patients were ventilated using FIO2 = 1,0 and PEEP = 3 cm H2O. Parameters of respiratory mechanics, ventilation, and ABG were recorded during three 5-min periods: 10 min prior to OLV (1), 20 min after onset of OLV (II), and after chest closure (III). Data analyses used nonparametric comparisons of paired samples (Wilcoxon, Friedman) with Bonferroni's correction. Significance was assumed at p < 0.05. Values are given as medians (range). RESULTS: 20 min after onset of OLV (II), resistance had approximately doubled compared with (1), compliance had decreased from 54 (36-81) to 50 (25-70) ml/cm H2O. TC remained stable at 1.4 (0.8-2.4) vs. 1.2 (0.9)-1.6) s. Institution of OLV was followed by a reproducible response of the ALV controller. The sudden changes in respiratory mechanics caused a transient reduction in VT by 42 (8-59)%, with RR unaffected. In order to reestablish the preset V'A, the controller increased inspiratory pressure in a stepwise fashion from 18 (14-23) to 27 (19-39) cm H2O, thereby increasing VT close to baseline (7.5 (6.6-9.0) ml/kg BW vs. 7.9 (5.4-11.7) ml/kg BW). The controller was, thus, effective in maintaining V'A. The minimum PaO2 during phase II was 101 mmHg. After chest closure, respiratory mechanics had returned to baseline. CONCLUSIONS: Respiratory mechanics during transition to and from OLV are characterized by marked changes in R and C into opposite directions, leaving TC unaffected. The ALV controller manages these transitions successfully, and maintains V'A reliably without intervention by the anesthesiologist. VT during OLV was found to be consistently lower than recommended in the literature.

Human issues and medical economics of endometriosis. Three- vs. six-month GnRH-agonist therapy.

OBJECTIVE: To project the efficacy and economic consequence of short-term intranasal gonadotropin-releasing hormone agonist (GnRH-a) for diagnosis of and therapy for endometriosis. STUDY DESIGN: Multicenter, placebo-controlled clinical trials of GnRH-a comparing three vs. six months of treatment, three months of retreatment and three months of postoperative treatment for the symptoms and signs of laparoscopically diagnosed endometriosis. RESULTS: The reduction in symptoms and signs of endometriosis was similar at the end of three months to the relief at six months. Retreatment was as effective as initial treatment, and the return of symptoms after laparoscopic surgery plus postoperative treatment for three months was delayed by approximately 18 months as compared to surgery alone. The projected charges for the surgical approaches (laparoscopy or minilaparoscopy) to diagnosis and therapy were 50-60% greater than those for the medical approach. CONCLUSION: GnRH-a administration for three months could be a cost-effective approach to the presumptive diagnosis and treatment of endometriosis among women with chronic pelvic pain.

Laryngeal mask airway position and the risk of gastric insufflation.

UNLABELLED: A potential risk of the laryngeal mask airway (LMA) is an incomplete mask seal causing gastric insufflation or oropharyngeal air leakage. The objective of the present study was to assess the incidence of LMA malpositions by fiberoptic laryngoscopy, and to determine their influence on gastric insufflation and oropharyngeal air leakage. One hundred eight patients were studied after the induction of anesthesia, before any surgical manipulations. After clinically satisfactory LMA placement, tidal volumes were increased stepwise until air entered the stomach, airway pressure exceeded 40 cm H2O, or air leakage from the mask seal prevented further increases in tidal volume. LMA position in relation to the laryngeal entrance was verified using a flexible bronchoscope. The overall incidence of LMA malpositions was 40% (43 of 108). Gastric air insufflation occurred in 19% (21 of 108), and in 90% (19 of 21) of these patients, the LMA was malpositioned. Oropharyngeal air leakage occurred in 42%, and was independent of LMA position. We conclude that clinically unrecognized LMA malposition is a significant risk factor for gastric air insufflation. IMPLICATIONS: Routine placement of laryngeal mask airways does not require laryngoscopy. In our study, fiberoptic verification of mask position revealed suboptimal placement in 40% of cases. Such malpositioning considerably increased the risk of gastric air insufflation.

Formative design of a virtual learning environment.

Current technology for 3D visualization, modeling and interaction allows the construction of attractive virtual environments for study of anatomy, surgery and other biomedical fields. The formative methodology for designing such environments is uncharted, but necessary before committing to large scale development. We present one such methodology undertaken during the design of a learning environment for biology for high school and middle school students. We expect to extend this design methodology to the development of environments for the teaching of medical subjects.

Use of nafarelin versus placebo after reductive laparoscopic surgery for endometriosis.

OBJECTIVE: To evaluate the efficacy of the GnRH agonist (GnRH-a) nafarelin compared with placebo administered for 6 months after reductive laparoscopic surgery for symptomatic endometriosis. DESIGN: Randomized, prospective, placebo-controlled, multicenter clinical trial. SETTING: Thirteen clinics including private practice and university centers. PATIENT(S): One hundred nine women aged 18-47 with laparoscopically proven endometriosis and pelvic pain who had undergone reductive laparoscopic surgery for endometriosis. INTERVENTION(S): Patients were randomized to receive either the GnRH-a nafarelin (200 micrograms twice daily) or placebo for 6 months. MAIN OUTCOME MEASURE(S): Time to initiation of alternative treatment (the length of time from beginning study medication to receiving alternative therapy or to deeming that the study drug was ineffective) and patient-reported and physician-assessed pelvic pain scores. RESULT(S): The median time to initiation of alternative treatment was > 24 months in the nafarelin group versus 11.7 months in the placebo group. Fifteen (31%) of 49 nafarelin-treated patients required alternative therapy, compared with 25 (57%) of 44 placebo-treated patients. The patients' pelvic pain scores dropped significantly in the nafarelin and placebo groups after 6 months of treatment. Physician summary ratings showed significant improvement in the nafarelin group and no significant changes in the placebo group after 6 months of treatment. CONCLUSION(S): Compared with placebo, nafarelin administered after reductive laparoscopic surgery for endometriosis significantly delays the return of endometriosis symptoms requiring further treatment.

Therapeutic efficacy and bone mineral density response during and following a three-month re-treatment of endometriosis with nafarelin (Synarel).

OBJECTIVE: Our goal was to determine the effects of a repeated course of the gonadotropin-releasing hormone agonist nafarelin on symptoms and signs of endometriosis and lumbar and distal radius bone mineral density. STUDY DESIGN: Forty-five women previously treated for 6 months with nafarelin, who had recurrent symptoms and signs of endometriosis, received 400 mcg/day of nafarelin intranasally for 3 months. Efficacy was evaluated by changes in severity of symptoms and signs. Lumbar bone mineral density was measured by dual-energy x-ray absorptiometry and distal radius bone mineral density by single-photon absorptiometry. Bone mineral density was also measured in 10 control volunteers. RESULTS: Repeated 3-month treatment significantly alleviated recurrent symptoms and signs of endometriosis. Lumbar bone mineral density decreased significantly by a mean of 2% at the end of treatment; this loss was restored within 3 to 6 months after treatment completion. No bone mineral density decline occurred in the radius. Bone mineral density changes in the control group were statistically insignificant. CONCLUSIONS: A repeated 3-month course of nafarelin treatment significantly relieved recurrent endometriotic symptoms and signs without sustained loss of bone mineral density.

[Anesthesia in endovascular treatment of aortic aneurysm. Results and perioperative risks]. / Ansthesie zur endovaskularen Therapie aortaler Aneurysmen. Verfahren und perioperative Risiken.

UNLABELLED: Surgical treatment of aortic aneurysms carries significant cardiovascular risks. Transvascular insertion of endoluminal prostheses is a new, minimally invasive treatment for aortic aneurysms. The pathophysiology of this novel procedure, risks and benefits of different anaesthetic techniques, and typical complications need to be defined. METHODS: With their informed, written consent, 19 male patients aged 48-83 years of ASA physical status III and IV with infrarenal (n = 18) or thoracic (n = 1) aortic aneurysms underwent 23 stenting procedures under general endotracheal (n = 9), epidural (n = 8), or local anaesthesia with sedation (n = 6). Intra-anaesthetic haemodynamics, indicators of postoperative (p.o.) oxygenation and systemic inflammatory response, and perioperative complications were analysed retrospectively and compared between anaesthetic regimens. RESULTS: Groups were well matched with regard to morphometry and preoperative risk profiles (Table I). The use of pulmonary artery pressure monitoring, incidence of intraoperative hypotensive episodes, and p.o. intensive care was more frequent with general anaesthesia. Groups did not differ in total duration of anaesthesia care, incidence and duration of intraoperative hypertensive, brady-, or tachycardic periods, incidence of arterial oxygen desaturation, use of vasopressors, colloid volume replacements, or antihypertensives (Table 2). Postoperatively, all groups showed a similar, significant systemic inflammatory response, i.e., rapidly spiking temperature (p.o. evening: mean peak 38.5 +/- 1.0 degrees C). leucocytosis, and rise of acute-phase proteins without bacteraernia (Table 3). During this period, despite supplemental oxygen, pulse oximetry revealed temporary arterial desaturation in 13 of 18 patients (70%) (Table 3). In 3 patients, hyperpyrexia was associated with intermittent tachyarrhythmias (n = 3) and angina pectoris (n = 1). There was no conversion to open aortic surgery, perioperative myocardial infarction, or death. CONCLUSIONS: Regional and local anaesthesia with sedation are feasible alternatives to general endotracheal anaesthesia for minimally invasive treatment of aortic aneurysms by endovascular stenting. However, invasive monitoring and close postoperative monitoring are strongly recommended with either method. Specific perioperative risks in patients with limited cardiovascular or pulmonary reserve are introduced by the abacterial systemic inflammatory response to aortic stent implantation. Hyperpyrexia increases myocardial and whole-body oxygen consumption, and can precipitate tachyarrhythmias. Hyperfibrino-genaemia may increase the risk of postoperative arterial and venous thromboses. Close monitoring of vital parameters and prophylactic measures, including oxygen supplementation, low-dose anticoagulation, antipyretics, and fluid replacement are warranted until this syndrome resolves.

[Adaptive lung ventilation (AVL). Evaluation of new closed loop regulated respiration algorithm for operation in the hyperextended lateral position]. / Adaptive Lung Ventilation (ALV). Evaluierung eines neuen closed loop-gesteuerten Beatmungsalgorithmus bei Eingriffen in überstreckter Seitenlage.

The lateral decubitus position is the standard position for nephrectomies. There is a lack of data about the effects of this extreme position upon respiratory mechanics and gas exchange. In 20 patients undergoing surgery in the nephrectomy position, we compared a new closed-loop-controlled ventilation algorithm, adaptive lung ventilation (ALV), which adapts the breathing pattern automatically, to the respiratory mechanics with conventionally controlled mandatory ventilation (CMV). The aims of our study were (1) to describe positioning effects on respiratory mechanics and gas exchange, (2) to compare ventilatory parameters selected by the ALV controller with traditional settings of CMV, and (3) to assess the individual adaptation of the ventilatory parameters by the ALV controller. The respirator used was a modified Amadeus ventilator, which is controlled by an external computer and possesses an integrated lung function analyzer. In a first set of measurements, we compared parameters of respiratory mechanics and gas exchange in the horizontal supine position and 20 min after changing to the nephrectomy position. In a second set of measurements, patients were ventilated with ALV and CMV using a randomized crossover design. The CMV settings were a tidal volume of 10 ml/kg body weight, a respiratory rate of 10 breaths/min, an I:E ratio of 1:1.5, and an end-inspiratory pause of 30% of inspiratory time. With both ventilation modes F1O2 was set to 0.5 and PEEP to 3 cm H2O. During ALV a desired alveolar ventilation of 70 ml/ kg KG.min was preset. All other ventilatory parameters were determined by the ALV controller according to the instantaneously measured respiratory parameters. Positioning induced a reduction of compliance from 61.6 to 47.9 ml/cm H2O; the respiratory time constant shortened from 1.2 to 1.08 s, whereas physiological dead space increased from 158.9 to 207.5 ml. On average, the ventilatory parameters selected by the ALV controller resembled very closely those used with CMV. However, an adaptation to individual respiratory mechanics was clearly evident with ALV. In conclusion, we found that the effects of positioning for nephrectomy are minor and may give rise to problems only in patients with restrictive lung disease. The novel ALV controller automatically selects ventilatory parameters that are clinically sound and are better adapted to the respiratory mechanics of ventilated patients than the standardized settings of CMV are.

[Combination of intravenous patient-controlled analgesia with epidural anesthesia for postoperative pain therapy]. / Kombination einer intravenösen Patientenkontrollierten Analgesie mit Epiduralanästhesie zur postoperativen Schmerztherapie.

The aim of this study was to prove the hypothesis that a combination of epidural anaesthesia with intravenous patient-controlled analgesia (PCA) could improve perioperative pain management. Patients of the urological department undergoing lower abdominal surgery were randomized for two different pain managements. Patients of group 1 (n = 37) were narcotized, intubated and ventilated for the operation; arriving at the recovery room, they were given a PCA-pump, the drug used was piritramide and the parameters were bolus 2.5 mg, blocking time 20 minutes and no basal infusion rate. In group 2 (n = 37) an epidural catheter was inserted preoperatively followed by narcosis with intubation and ventilation. Additionally, epidural anaesthesia was performed intraoperatively using bupivacaine 0.5%. For postoperative pain management, patients of group 2 were also given a PCA-pump (same parameters as mentioned above) and a continuous epidural infusion was started additionally (bupivacaine 0.1875%, infusion rate 8 ml/h). Patients were monitored at the urological ICU for 36 hours. Assessment of pain (6-degree scale), grade of sedation (4-degree scale), cumulative doses of piritramide, heart rate, blood pressure, respiratory rate, in group 2 additional motoric function (Bromage) and degree of epidural anaesthesia were recorded at fixed time intervals: 0, 1, 2, 3, 5, 8, 11, 15, 19, 24, 28, 32, 36 hours. There was no difference regarding age of patients or type of operation. Assessment of pain showed a significant pain reduction in group 2 compared to group 1 during the first 8 hours. This result was underlined by a significantly smaller dose of piritramide. All other parameters showed no differences except lower blood pressure and heart rate in group 2 for the first three hours. The benefits of better pain management contrast with the risks resulting from combining the two techniques. In our patients we found an improvement of pain management in the early postoperative period. The combination of epidural anaesthesia with intravenous patient-controlled analgesia can be regarded as a further possibility for treating postoperative pain in the sense of "balanced pain management".