Functional characterization of the ectopically expressed olfactory receptor 2AT4 in human myelogenous leukemia

The olfactory receptor (OR) family was found to be expressed mainly in the nasal epithelium. In the last two decades members of the OR family were detected to be functional expressed in different parts of the human body such as in liver, prostate or intestine cancer cells. Here, we detected the expression of several ORs in the human chronic myelogenous leukemia (CML) cell line K562 and in white blood cells of clinically diagnosed acute myeloid leukemia (AML) patients by RT-PCR and next-generation sequencing. With calcium-imaging, we characterized in greater detail the cell biological role of one OR (OR2AT4) in leukemia. In both cell systems, the OR2AT4 agonist Sandalore-evoked strong Ca²⁺ influx via the adenylate cyclase-cAMP-mediated pathway. The OR2AT4 antagonist Phenirat prevented the Sandalore-induced intracellular Ca²⁺ increase. Western blot and flow cytometric experiments revealed that stimulation of OR2AT4 reduced the proliferation by decreasing p38-MAPK phosphorylation and induced apoptosis via phosphorylation of p44/42-MAPK. Furthermore, Sandalore increased the number of hemoglobin-containing cells in culture. We described for the first time an OR-mediated pathway in CML and AML that can regulate proliferation, apoptosis and differentiation after activation. This mechanism offers novel therapeutic options for the treatment of AML.

[Off-label use of drugs in pediatric emergencies: limitations and grey areas of drug approval]

In the medical treatment of children drugs are frequently used outside the boundaries of the approved licensing and use under the terms of off-label use is possible. However, this requires critical reasoning and experience with the drug involved. With help of a traffic light colored spreadsheet this article illustrates the limitations, problems and possibilities of pharmacotherapy in pediatric emergencies or pediatric anesthesia. Of the 45 emergency drugs listed in this article most can be used in childhood, at least under specific conditions. Licensing restrictions occur especially in the newborn period and infancy resulting in frequent off-label use. Severe pitfalls, such as the propofol infusion syndrome after long-term sedation with propofol under the age of 16 years, emphasize the need for serious reflection on the substances involved. Decisions regarding pharmaceutical therapy should be based on the current standard of medical knowledge. When official recommendations from pharmaceutical companies are missing, treatment decisions for off-label use can be based on guidelines, study and literature databases or recommendations in medical journals.

Intraoperative thrombolysis in a patient with cardiopulmonary arrest undergoing caesarean delivery

Thromboembolic events during pregnancy remain a major cause of morbidity and mortality with possible catastrophic sequelae for the patient. The decision whether to use high-risk therapeutic thrombolytics during pregnancy or perinatally is complicated and many considerations pertain. We report on the thrombolytic management of a 34-year-old woman who had an asystolic cardiac arrest secondary to massive pulmonary embolism while undergoing emergency caesarean delivery. The patient was thrombolysed during successful cardiopulmonary resuscitation. Return of spontaneous circulation was accompanied by massive uterine bleeding. Instead of performing a postpartum hysterectomy, the uterus was preserved through continuous manual pressure and packing for four hours by the obstetric team until haemostasis was achieved. The patient survived and was later discharged without any major neurological deficit.

Continuous spinal anesthesia versus continuous femoral nerve block for elective total knee replacement

BACKGROUND

Continuous spinal analgesia (CSA) and continuous femoral nerve blockade (CFNB) are well-established procedures for postoperative pain relief. This study compares the efficacy, adverse effects and complications associated with these two analgesic methods in patients undergoing total knee arthroplasty (TKA).

METHODS

Data were analyzed from consecutive patients undergoing TKA under either CSA or spinal anesthesia plus CFNB. Quality of analgesia was assessed based on opioid consumption and pain intensity (visual analogue scale [VAS] where 0=no pain and 10=utmost imaginable pain) until postoperative day 4. In addition, joint mobility was assessed, and any adverse reactions or side effects were noted.

RESULTS

Sixty-two patients had satisfactory postoperative pain relief, and maximum pain scores were reported between 12 and 24 hrs. Median pain scores in the CSA group were significantly lower than those in the CFNB group (1.0 [0.9-1.9] vs. 2.0 [1.5-3.6] for resting pain and 2.0 [1.7-3.1] vs. 5.0 [3.0-5.5] for dynamic pain, respectively; P<0.001 for days 0 and 1; P<0.05 for all other days). Piritramide consumption was significantly higher in the CFNB group (P<0.01). There were no significant differences between the groups for postoperative mobility of the joint or patient satisfaction.

CONCLUSION

Both methods demonstrated analgesic efficacy after total knee arthroplasty, although there was less pain severity and opioid consumption use reported with continuous spinal analgesia. However, the use of continuous spinal analgesia is limited by concerns about the risk profile and absence of approved devices for continuous intrathecal infusion.

[Scoliosis surgery in children from the viewpoint of anaesthesiology]

Anaesthesia for scoliosis surgery in children is a challenge for the paediatric anaesthesiologist. The large range of underlying pathologies causing deranged physiology in an inhomogeneous patient group ranging from neonates to adolescents necessitates diligent and individual preparation for each case. Due to the invasiveness of the operation demanding anaesthetic care is necessary. This review highlights current approaches to monitoring, anaesthetic regimen, positioning of the patient, blood conservation and transfusion, age-related pathophysiology, ventilation and postoperative pain therapy. The introduction of neurophysiologic spinal cord monitoring requires certain adaptations of the anaesthetic regimen to suit technological advances.

Continuous spinal analgesia or opioid-added continuous epidural analgesia for postoperative pain control after hip replacement

BACKGROUND AND OBJECTIVE

Continuous spinal anaesthesia and continuous epidural anaesthesia are both able to provide adequate postoperative pain relief. Combining local anaesthetics and opioids results in synergistic effects. The purpose of this randomized, prospective study was to compare quality of analgesia, side-effects and patient's satisfaction between spinal bupivacaine alone and epidural bupivacaine with sufentanil postoperatively.

METHODS

Fifty-nine patients scheduled for hip arthroplasty were randomly assigned either to Group 1 receiving continuous spinal anaesthesia or Group 2 receiving continuous epidural anaesthesia. Postoperatively, those in Group 1 received a 1 mL bolus followed by a continuous infusion of 10 mL/24 h of bupivacaine 0.25 %. Those in Group 2 received a 5 mL bolus of lidocaine 2%, followed by a continuous infusion of bupivacaine 0.25% with sufentanil 0.001 mg mL(-1) at 4 mL h(-1). Pain was measured using a verbal rating score and a visual analogue scale.

RESULTS

Group 1 and Group 2 of 43.3% and 37.9% reported complete analgesia on the verbal rating score. No statistically significant difference was found in the visual analogue scale. Nausea and vomiting occurred significantly more often in Group 2. The patient satisfaction rates did not differ significantly.

CONCLUSIONS

Continuous spinal analgesia with bupivacaine alone and continuous epidural analgesia with bupivacaine/sufentanil are both effective for postoperative pain relief after hip replacement. Those patients in the epidural group reported better analgesia but had a higher rate of postoperative nausea and vomiting. Efficacy of pain therapy did not correlate with patient satisfaction.

Treatment of pain in trauma patients with injuries of the upper limb

Since preoperative pain therapy of a trauma patient did not play an outstanding role in the past, this article shall give information about the adequate treatment of such patients, which can be mainly divided into three phases: the prehospitalisation phase with stabilisation of the trauma patient, the early phase of hospitalisation with further stabilisation, diagnosis and surgery, and finally the postoperative phase with corresponding treatment. An optimal analgesic in the prehospitalisation phase should guarantee good analgesic effects, rapid onset and good controllability, simple handling and the opportunity to combine it with other medication. In addition, it should prevent a wide therapeutic range and the absence of side effects. Opioids and ketamine are available for acute pain therapy after trauma. The main opioids used are piritramide and pethidine, with piritramide acting as a sedative at the same time and with pethidine preventing the stronger analgesic effect. The intravenous use of ketamine has become established in trauma patients because of its excellent analgesia at subanaesthetic doses. Especially in multiple trauma patients, the indication for general anaesthesia with intubation should be established on a liberal basis. Nevertheless, for some patterns of injury regional techniques may be advantageous; therefore, this article describes the possible regional procedures (such as intravenous regional anaesthesia or block of peripheral nerves). Concerning the postoperative phase, an individual pain management can be guaranteed by systemic pharmacotherapy and regional catheter techniques, for example the brachial plexus blockade that results in a long period of free pain.

Effects of the phlebotropic drug Daflon 500 mg on postischemic reperfusion injury in striated skin muscle: a histomorphologic study in the hamster

The objective of this study was to investigate the effects of the purified, micronized, flavonoid fraction Daflon 500 mg (S 5682, 90% diosmin and 10% hesperidin) on tissue damage and leukocyte emigration in striated skin muscle after ischemia-reperfusion, as assessed by histomorphometric analysis. The experimental model used was the transparent dorsal skin fold chamber in the awake Syrian golden hamster. Sixty-four animals were randomly allotted to two treatment groups and time points of investigation. Animals were fed with 30 mg kg(-1) body weight Daflon 500 mg (n = 32) or its vehicle, 5% Arabic gum solution (n = 32), as control 8 hours before ischemia. Before induction of a tourniquet ischemia of 4 hours' duration and at 0.5, 2, and 24 hours of reperfusion, tissue sections were preserved for light and electron microscopic analysis (n = seven or eight animals per time point). The number of intravascular and extravascular leukocytes was determined by light microscopic analysis of esterase-positive leukocytes. For quantitative analysis of ischemia-induced endothelial cell damage, the endothelial thickness of capillaries was calculated by a computer-assisted imaging system, whereas the ischemic tissue damage was assessed by means of a score system (grade 0-3) by an independent investigator. The number of emigrated leukocytes was significantly reduced in Daflon 500 mg-treated animals compared with numbers found in control animals. The histomorphologic muscle fiber damage increased after reperfusion in both groups but was significantly reduced in the Daflon 500 mg-treated animals 2 and 24 hours after reperfusion. These results suggest that the emigration of leukocytes plays an important role in the development of postischemic reperfusion injury of striated skin muscle.

Effects of the phlebotropic drug Daflon 500 mg on postischemic microvascular disturbances in striated skin muscle: an intravital microscopic study in the hamster

The objective of this study was to investigate the effects of the micronized purified flavonoid fraction Daflon 500 mg (90% diosmin and 10% hesperidin) on I/R-induced microvascular leukocyte-endothelium interaction and leakage of the high molecular weight plasma tracer FITC-dextran (relative molecular mass, 150 kd) as assessed in the striated skin muscle of the dorsal skin fold chamber model in the hamster. Intravital fluorescence microscopy was used for analysis of microvascular perfusion, leukocyte-endothelium interaction, and macromolecular leakage of FITC-dextran 150 kd in the striated skin muscle of the hamster. A tourniquet ischemia of 4 hours' duration was induced followed by reperfusion. Animals were treated with an oral administration of Daflon 500 mg (n = six) or its vehicle (5% Arabic gum solution, n = six) for 8 days at a daily dose of 30 mg/kg body weight. Measurements in the microcirculation were made before the 8-day feeding protocol before induction of ischemia and at 0.5, 2, and 24 hours of reperfusion. In the absence of I/R, no differences in microvascular perfusion, leukocyte-endothelium interaction, and macromolecular leakage were found in Daflon 500 mg and vehicle-treated control animals before and after administration of the drugs. Induction of ischemia and reperfusion, however, elicited a significant increase in venular leukocyte rolling and sticking in vehicle-treated animals, which was accompanied by enhancement of leakage of FITC-dextran 150 kd into the perivascular tissue. Treatment with Daflon 500 mg had no effect on postischemic leukocyte rolling and sticking, and macromolecular leakage of FITC-dextran 150 kd from arterioles and postcapillary venules was significantly reduced. These data indicate that Daflon 500 mg preserves the endothelial barrier function of striated skin muscle arterioles and venules after I/R, which appears to be independent of an action on postischemic intravascular leukocyte rolling and sticking.

Continuous spinal anaesthesia or continuous epidural anaesthesia for post-operative pain control after hip replacement?

Both continuous spinal anaesthesia and continuous epidural anaesthesia are supposed to provide adequate post-operative pain relief. The purpose of this randomized, prospective study was to compare the quality of analgesia, occurrence of side effects and patient satisfaction between spinal and epidural administration of bupivacaine during the first post-operative 72 h. One hundred and two patients scheduled for hip arthroplasty were randomly assigned to one of two groups: Group 1 received continuous spinal anaesthesia for intra-operative and post-operative management, Group 2 received continuous epidural anaesthesia. Immediately after surgery, the continuous spinal anaesthesia-group received a 1-mL bolus (bupivacaine 0.25%), followed by a continuous infusion of 10 mL over 24 h. The continuous epidural anaesthesia-group received a 10-mL bolus (bupivacaine 0.25%), followed by 2 mL h-1. The level of pain was gauged from a verbal rating score and from a visual analogue scale; the degree of motor blockade was recorded using the Bromage score. In the continuous spinal anaesthesia-group 90.2% reported complete analgesia on the verbal rating scale, but only 21.6% of the continuous epidural anaesthesia-group did. The visual analogue scale scores given by the continuous spinal anaesthesia-group were significantly lower than those of the continuous epidural anaesthesia-group. The percentage of patients with a motor block was significantly higher in the continuous spinal anaesthesia-group on the day of surgery and at the first post-operative day. During the first 24 h, nausea and vomiting occurred more often in the continuous epidural anaesthesia-group. The satisfaction was considered excellent in 92.2% of the continuous spinal anaesthesia-group and in 70.6% of the continuous epidural anaesthesia-group. It is concluded that continuous spinal anaesthesia and continuous epidural anaesthesia are effective and safe for post-operative pain relief after hip replacement. Compared with continuous epidural anaesthesia, continuous spinal anaesthesia provides faster onset of pain relief, ensures better analgesia and results in more satisfied patients.

No risk of metal toxicity in combined spinal-epidural anesthesia

Using the single level needle-through-needle technique for combined spinal-epidural anesthesia (CSE) may introduce very fine metal particles abraded by the spinal needle from the inner ground edge of the Tuohy needle into the patient. Either the local anesthetic administered epidurally or the peridural catheter may also pass intrathecally through the hole in the dura made by the spinal needle. To examine these concerns, the needle-through-needle technique was simulated in an in vitro model (18-gauge Tuohy needle; 27- or 29-gauge Quincke needle). The presence of abraded metal particles was identified by atomic absorption spectrography (AAS). The needles were then examined under an electron microscope. Metal particles could not be identified by using AAS in the needle-through-needle technique after normal clinical use, nor could traces of use be revealed by using an electron microscope to examine the Tuohy needle. With intentionally rough handling and caudal orientation of the spinal needle tip, minimal scratches could be seen by using an electron microscope, but there were no metal particles detected by AAS. In an anatomical preparation, the possible passage of the epidural catheter anesthetic through the dural puncture hole into the cerebrospinal fluid compartment was investigated endoscopically. Neither passage of dyed epidural local anesthetic nor penetration of the epidural catheter into the cerebrospinal fluid compartment could be demonstrated by endoscopy. We conclude that the needle-through-needle-technique is an acceptable way of performing CSE anesthesia. Endangering the patient by an unintentionally intrathecal misplacement of the epidural catheter seems to be very unlikely based on our in vitro model if small spinal needles (27- or 29-gauge) are used.

IMPLICATIONS

Atomic absorption spectrography shows no contamination of the intrathecal compartment by abraded metal particles from the Tuohy needle by combined spinal-epidural anesthesia with the needle-through-needle technique. In vitro, neither passage of dyed epidural local anesthetic nor penetration of the epidural catheter into the cerebrospinal fluid compartment could be demonstrated by endoscopy.

In vitro investigation of cerebrospinal fluid leakage after dural puncture with various spinal needles

Postspinal headache is one of the most common complications of spinal anesthesia and has repeatedly led to controversy concerning needle size and configuration. In an in vitro investigation, we measured cerebrospinal fluid (CSF) leakage with Sprotte, Whitacre, Quincke, and Atraucan needles under physiological conditions in human dura. The puncture characteristics were examined under an electron microscope. The pencil-point needles show 2-3 times less leakage of CSF compared with the cutting Quincke needles of corresponding size. Between the Sprotte and the Whitacre needles, there were no significant differences. The least loss of CSF occurred with the 26-gauge Atraucan needle. Under the electron microscope, a sharply delineated, persistent perforation channel was shown with the Quincke needles, which may explain the high CSF loss. With pencil-point needles, which push the tissue apart bluntly, a large opening on the inside is found, with some tearing of the dura. However, in contrast to the cutting needles, a persistent perforation channel is not manifested. The 26-gauge Atraucan needle, which both cuts and pushes apart conically, shows a relatively discrete opening on the inside, with slight tears in the dura and arachnoidea but without a visible perforation channel. The results of our study show that larger needles (26-gauge Atraucan) that are easier to handle can lead to good and, in some cases even better, puncture results if they have characteristics of both the cutting and the pencil-point needles.

IMPLICATIONS

We compared several brands of pencil-point and standard cutting spinal needles of varying sizes. All pencil-point needles had less cerebrospinal fluid leakage, the least loss occurring with 26-gauge Atraucan needles. Electron microscopic examination of the dura after puncture showed characteristic findings with each needle type. We conclude that the combined cutting and pencil-point characteristics seen in the Atraucan needle may have clinical advantages.

Intrathecal local anesthetic distribution with the new spinocath catheter

BACKGROUND AND OBJECTIVES

Microcatheters have been linked in some cases to the development of cauda equina syndrome, which may be further traced to the maldistribution of the local anesthetic. A long injection time via the microcatheters contributes to the inadequate mixing. With the new Spinocath catheter, considerably shorter injection times can be achieved due to larger internal size. This study examined whether this leads to more homogeneous intrathecal distribution without causing greater trauma to the dura.

METHODS

In an in vitro model of the spinal canal, the distribution of hyperbaric and isobaric 0.5% bupivacaine (2.5 mL) as well as 5% lidocaine (2.5 mL) was examined after injection via the 28-gauge CoSpan catheter (Kendall, Healthcare, Mansfield, MA), the 22-gauge Spinocath catheter (Braun, Melsungen, Germany), and a 29-gauge Quincke needle (Becton Dickinson, Rutherford, NJ). The local anesthetic concentration in the vertebral interspaces T12-L1 to L5-S1 was measured via gas chromatography 3 and 10 minutes after injection. In addition, the morphologic puncture characteristics of human dura were examined with the halftone electron microscope, after puncture with the catheters and needle.

RESULTS

After injection through the 28-gauge CoSpan catheter, caudal segments of the spinal canal showed peak concentrations up to a maximum of 1,147 microg/mL bupivacaine or 8.5 mg/mL lidocaine with hyperbaric solutions, which did not decrease over the 10 minutes of measurement. After injection through the Spinocath catheter, there was a homogeneous distribution with data peaks of approximately 350 microg/mL bupivacaine or 4.2 mg/mL lidocaine similar to the data found after injection through the spinal needle.

CONCLUSIONS

The new Spinocath catheter allows a better mixing of the local anesthetic with the cerebrospinal fluid. Because of significantly shortened injection times, hyperbaric solutions also show a more homogeneous distribution. Although the Spinocath catheter has a larger inner diameter than the other microcatheters, it appeared to cause less trauma to the dura.

Cell survival following bone-anterior cruciate ligament-bone allograft transplantation: DNA fingerprints, segregation, and collagen morphological analysis of multiple markers in the canine model

Bone-anterior cruciate ligament-bone allograft transplantation has become recognized as a potential solution to reconstruction of the anterior cruciate ligament (ACL). The purpose of this study was to determine the time-dependent fibrocyte donor cell survival rate after cryopreserved bone-ACL-bone allograft transplantation. Additionally, bony incorporation of the pediculated bone plugs was examined. The ability to successfully transplant allogenous ACL fibrocytes and have them survive has not previously been documented. In this study, DNA fingerprints identified and documented the survival rate of the cellular DNA in transplanted ACL allografts for ACL re-construction in the knee joints of 10 skeletally mature dogs. At 4, 8, 26 and 52 weeks after ACL allograft transplantation, DNA probes, H & E, Giemsa, Goldner, PAS and polarized light staining was done to demonstrate the time-dependent changes in the allografts after transplantation. At 4 weeks host fibrocytes began to grow into the graft; however, histologically the cells could not be distinguished as to host or donor origin. After 4 weeks the DNA pattern reflected only the band pattern of the host. This reveals the early cellular infiltration activity of the host into the ACL allograft, also demonstrated in the light microscopy stainings. The survival rate of transplanted allogenous ACL fibrocytes had not been documented before this study. There is no evidence that ACL allograft cells survive in the intra-articular environment of the host's knee. Within 4 weeks ACL allografts became completely repopulated with host cells. The cells that migrate early into the ACL allografts are probably of synovial origin because they are present before revascularization and collagen reorganization occur. We conclude from this study that viable cells in transplanted ACL allografts did not survive longer than 4 weeks after intra-articular transplantation. Advances in molecular biology may offer new approaches to alter or stimulate fibrocyte population and function in the transplanted ACL allograft used for ACL reconstruction. New methods to maintain the viability of donor cells may be necessary to improve the biomechanical and histological properties of autografts or allografts for ACL reconstruction.

Effects of Daflon 500mg on postischemic macromolecular leak syndrome in striated skin muscle of the hamster

We have recently shown that the purified micronized flavonoid fraction (90% diosmin and 10% hesperidin) Daflon 500 mg attenuates reperfusion injury in the striated skin muscle of the hamster. Herein, we report on the action of Daflon 500 mg on postischemic macromolecular leakage of FITC-dextran 150 kD provoked by tourniquet ischemia. Intravital fluorescence microscopy was used for analysis of macromolecular leakage in the microcirculation model of the hamster. A tourniquet ischemia of 4 h duration was induced followed by reperfusion. Animals were treated by gavage of Daflon 500 mg (n = 6) for 8 days at a daily dose of 30 mg kg(-1) body weight. Control animals received equivalent volumes of the vehicle (5% Arabic gum solution, n = 6). Measurements of the microcirculatory parameters were made before induction of ischemia and at 0.5, 2 and 24 h of reperfusion. After induction of ischemia, macromolecular leakage from postcapillary venules was significantly enhanced in vehicle-treated animals. Treatment with Daflon 500 mg significantly attenuated macromolecular leakage of FITC-dextran 150 kD. Preliminary data from a histomorphometric analysis (n = 3/experimental group) indicated that the number of emigrated (extravascular) leukocytes after ischemia reperfusion was markedly reduced in Daflon 500 mg-treated animals as compared to controls. These data indicate that Daflon 500 mg prevents leakage of the macromolecular tracer FITC-dextran 150 kD from postcapillary venules after postischemic reperfusion, presumably through an inhibitory action on the emigration of activated leukocytes.

[Continuous spinal anesthesia]

Continuous spinal anaesthesia (CSA) is a further means of central nerve block for anaesthesia besides single-shot spinal (SSS), combined spinal/epidural, and epidural anaesthesia. Major advantages compared to SSS are the possibility of subsequent injection of local anaesthetic via the indwelling catheter, which enables analgesia to be maintained over a longer period. Moreover, the haemodynamic effects are diminished by this mode of application. The most important advantages of CSA compared to continuous epidural anaesthesia are the more rapid onset of action, better quality of analgesia, and better muscle relaxation. Since small doses of local anaesthetic are used in CSA, there is less danger of systemic toxic reactions. The microcatheters used up to now for CSA are introduced via relatively large needles that cause perforation trauma to the dura, resulting in loss of cerebrospinal fluid (CSF) and thus a higher incidence of post-dural punctive headache. Hence, further technical developments must have the objectives of reducing needle diameter and increasing catheter diameter. Perforation trauma to the dura is reduced by using small needles. Use of a larger catheter enables better mixing of the local anaesthetic with the CSF, and it is easier to aspirate CSF in order to establish the correct position of the catheter.

[Circulatory reactions under spinal anesthesia. The catheter technique versus the single dose procedure]

Life-threatening cardiovascular complications are a serious risk even for healthy patients during spinal/epidural anaesthesia. The incidence of fatal cardiovascular complications for epidural anaesthesia is 1:10000, for spinal anaesthesia 1:7000. In contrast, general anaesthesia has an overall mortality of only 1:28000. Administration of IV fluids to minimise the haemodynaemic reactions of beginning sympatholysis is not always sufficient. In this study, we examined whether fractionated application of local anaesthetics via a spinal catheter would provide better haemodynamic stability.

METHODS

In a prospective study, we examined the haemodynaemic reactions of 300 patients during single-dose (n = 150) versus continuous spinal anaesthesia (CSA) (n = 150). Isobaric bupivacaine 0.5% was given through a 29 G Quincke needle (3.5 ml) or a 28 G spinal catheter (1.5 ml as a bolus, followed by 1 ml/10 min until an anaesthetic level of T12 was reached).

RESULTS

The sensory and motor effects of both methods were comparable. The T12 level of anaesthesia was achieved with the single-dose method after 10.5 min and with the continuous method after 19.1 min. After single-dose anaesthesia, the blood pressure dropped by 16.5% and the heart rate by 12% compared to the control values. During CSA no significant blood pressure changes were recorded; the heart rate decreased by 8%. In 15 cases vasoconstrictors had to be given to stabilise the lowered blood pressure after single-dose anaesthesia.

CONCLUSION

With the use of CSA, the haemodynamic effects of sympatholysis can be minimised. This method thus has advantages, especially for high-risk cardiovascular patients.

[Spinal para-medullary conduction anesthesia in therapy with anticoagulant drugs]

Epidural and spinal blocks can lead to iatrogenic bleeding in the spinal canal. Incidence of this severe complication is considered low, but the risk of irreversible neurological defects for the patient requires increased attention by the anaesthetist. The perioperative risk is higher in patients under anticoagulant therapy. The different pharmacodynamics and pharmacokinetics of practically relevant anticoagulants are discussed and recommendations for the performance of centroneuraxis blocks in patients under anticoagulant therapy are given.

[Erythropoietin therapy during frequent autologous blood donations. Dose-finding study]

Avoidance of homologous blood products and patients' demand for preoperative autologous blood donation programs are increasing. As many of these patients are older, with a compromised cardiovascular system and a slow response of the erythropoietic system when anemia occurs, the feasibility and benefit of autologous blood donation is often limited. Augmentation of preoperative blood donation by therapy with recombinant human erythropoietin (rHuEPO) has been described in animal models and in patients. METHODS. In a multicenter, controlled, randomized trial, 49 patients scheduled for orthopaedic or vascular surgery received 0 (control group, n = 9), 200 (n = 10), 300 (n = 11), 400 (n = 10) or 500 (n = 9) U/kg rHuEPO (Erypo, Cilag, Sulzbach, distributor Fresenius, Oberursel, Germany) subcutaneously twice a week for 3 weeks while every week 450 ml blood was collected. Iron sulphate 100 mg was prescribed orally twice a day. Patients were ineligible if they had uncontrolled hypertension, recent myocardial infarction, haematological disorders or a history of seizures. Blood donation had to be cancelled if the haematocrit was below 30%. RESULTS. There was a significant (ANOVA) drop of the haematocrit value only in the control group, and end-point values for haematocrit and haemoglobin were significantly elevated in the 400 and 500 U/kg groups compared with the control group (Table 9). DISCUSSION. The erythropoietic stimulus of phlebotomy for autologous blood donations is often not efficient enough to guarantee a constant haematocrit. Lowering of the preoperative haematocrit jeopardizes the aim of avoidance of homologous blood transfusions. rHuEPO increased the efficiency of autologous blood collections, as predonation haematocrit values could be preserved in the high-dosage groups. As a consequence, homologous transfusions could be avoided. However, there were broad interindividual differences in the erythropoietic response, possibly due to limitations in iron availability. Adverse effects of rHuEPO therapy, such as hypertension, thrombosis or neurologic disorders, are mostly reported in patients with terminal kidney failure. No such disturbances were observed in the present study. CONCLUSION. rHuEPO ameliorates the preoperative decrease of haemoglobin and haematocrit values due to autologous blood donations in a dose-related fashion. The individually adjusted dosage of rHuEPO and iron supplementation merits further investigation.

Continuous spinal anesthesia: mechanical and technical problems of catheter placement

BACKGROUND AND OBJECTIVE

Although continuous spinal anesthesia with microcatheters has a number of advantages, there are also some drawbacks: technical problems in advancing the catheter, the possibility of traumatizing neural structures, the development of cauda equina syndrome, and maldistribution of the local anesthetic.

METHODS

Spinaloscopy was performed with a 2-mm-diameter endoscope in fresh cadavers to visualize the fate of the catheters, as well as the distribution of the local anesthetic administered through these fine-bore catheters. Midline and paramedian approach achieved an easy insertion of the 28-gauge catheter as long as the 22-gauge needle was not advanced too far into the subarachnoid space, thereby making it impossible for the catheter to bend at the anterior wall of the dura mater.

RESULTS

Injection of methylene blue-colored hyperbaric local anesthetic through the catheter revealed an inhomogenous distribution with pooling in the caudal segments. After the catheter tip leaves the needle, the catheter should be advanced only 2-3 cm to avoid coiling, possible damage of the nerve roots, or malpositioning in preformed pouches.

CONCLUSION

To take advantage of continuous spinal anesthesia, a meticulous technique is required.

[Erythropoietin--physiology and therapeutic potentialities]

Erythropoietin (EPO) is the main regulatory hormone for the control of erythropoiesis. EPO leads to enhanced mitosis and differentiation of erythroid precursors in the bone marrow. The major stimulus for EPO-formation is anaemia of various origin, resulting in an exponential relation between EPO levels and a decrease in haematocrit. Another important stimulus for increased EPO production is a fall of the arterial oxygen tension caused by either cardiopulmonary disorders or by a decrease of the oxygen tension in the inspiratory gas. Human erythropoietin was first isolated and purified from a large amount of urine of patients with aplastic anaemia. After the EPO gene had been cloned and expressed, biotechnically produced recombinant human erythropoietin (rHu-EPO) became available for clinical trials. EPO deficiency appears to be the major cause of renal anaemia, and hence the treatment of these patients is the most important indication for clinical use. Encouraging results in patients whose anaemia is not of renal origin have also been reported, using treatment with rHu-EPO. In preoperative autologous blood donation programmes prior to elective surgery, rHu-EPO therapy improved the amount of donated blood and ameliorated the decrease of haematocrit values. Side effects such as hypertension, thrombosis, hypercalcaemia, elevated liver enzymes were rare and were mostly related to the underlying disease.

[The reuse of 29-gauge spinal needles following combined spinal-epidural anesthesia]

The technique of combined spinal epidural anaesthesia (CSE) combines the versatility of spinal with the variability of epidural anaesthesia. Spinal application of the local anaesthetic achieves a fast response, reliable sensorial and motor block at a low dose with little toxicity. The epidural catheter allows for the duration of surgical anaesthesia to be extended and provides analgesia for the postoperative period. As the incidence of post dural puncture headache (PDPH) is inversely related to the size of the spinal needle, PDPH rarely or never occurs when 29 gauge needles are used. In 1775 parturients receiving spinal anaesthesia for caesarean section, Dittmann et al. [4] reported an incidence of PDPH of 1.37% with 29 gauge needles. The 29 gauge needle produced by Becton-Dickinson is the one now most frequently used for this technique. It is recommended that these needles be reused after resterilization. The objective of this study was to examine how clean 29 gauge spinal needles really are after resterilization. MATERIALS AND METHODS. Fifteen needles (29 gauge; Becton-Dickinson) were routinely used for combined spinal epidural anaesthesia. After identification of the epidural space at the L3-4 spinal segment with the 18 gauge Tuohy needle, the 29 gauge needle was advanced through the Tuohy needle. Immediately after use the needles were cleaned, rinsed with 20 ml distilled water, dried with pressurized air and subsequently resterilized in gas. Preparation of the used needles was in accordance with the manufacturer's recommendations ("wash, rinse, dry, sterilize before initial and each subsequent use") and with generally accepted principles [6]. Two needles were additionally cleaned in an ultrasonic bath for 15 min. The needles were examined using a scanning electron microscope. After this analyses, eight needles were sterilized again and then taken for hygienic examination. They were incubated with trypticase soy broth and checked for bacterial growth. RESULTS. Scanning electron microscopy (ScEM) showed organic impurities on all needles. These impurities were equally distributed among all needles. Even the two cleaned in the ultrasonic bath were not free of organic particles. However, no material defects or damage could be seen. Hygienic evaluation proved sterility as no bacterial growth could be detected. CONCLUSION. Owing to the possibility of medico-legal consequences, which sometimes occur a long time after anaesthesia has been given, we think it is unwise to reuse such needles. We hope that disposable and cheap 29 gauge needles will soon become available.

[Subdural intra-arachnoid spread of local anesthetics. A complication of spinal anesthesia]

Accidental subdural injections and catheterisations are a complication of epidural and spinal anaesthesia. The incidence of subdural spread in myelographies is estimated to be over 10% by the spinal technique. With spinaloscopy in an anatomic human model, we analysed the puncture process and the influence of different needle types on the incidence of subdural injection. We compared 22-gauge Sprotte, Quincke, and 18-gauge Tuohy needles in median and paramedian approaches with various bevel orientations. METHOD. The studies were performed in a preserved and recently expired cadaver donated to the Institut für Anatomie, Westfälische Wilhelms-Universität, Münster. The spinal column from T12 to S1, together with the back musculature (in order to preserve the normal curvature of the spine), were removed from the cadaver. Spinaloscopy was performed with a 4-mm endoscope with a 0 degree optic (Storz, Tuttlingen, Germany). All observations were made in the lumbosacral region of the dissected preparation. The endoscope was inserted from the caudal end of the spinal canal and, depending on the observations being made, the spinal canal was filled with air or artificial cerebrospinal fluid (CSF). To obtain information on the distribution of local anaesthetics injected into the subarachnoid space, 0.5% bupivacaine was coloured with a small amount of 1% methylene blue. The distribution of the coloured anaesthetic was clearly visible during and after injection. RESULTS. Needle insertion: Multiple observations were made using median or paramedian advancement of the needle into the spinal canal. With all needles, including the pencil-point, we saw an unexpected inward movement of the dura to the epidural space before penetration. This dural movement was independent of the direction of the dural fibres in the lumbar area. Distribution of local anaesthetics: Our observations indicate that difficulty with injecting drugs occurred when needle insertion was stopped too close to the dura, especially with the Sprotte needle. After manually registered penetration of the dura, the lateral opening of the needle only partially penetrates the dura. This allows CSF to appear in the needle hub, and injection into the vertical subdural space is possible. In all cases with the Sprotte needle, we could reproduce deposition of methylene-blue-coloured local anaesthetics into the subdural space. With the Quincke and Thuohy needles, it was not possible to deposit local anaesthetics into the subdural space in this model. CONCLUSION. Spinaloscopy was done in a non-fixated anatomic preparation of a spinal column with a 4-mm, 0 degree endoscope. From these observations we conclude that both manually registered penetration of the dural and the appearance of CSF in the needle hub can mimic correct needle position. Especially with the lateral opening of the Sprotte needle, deposition of local anaesthetics in the subdural space is possible.

[Spinal endoscopy in the detection of problems caused by continuous spinal anesthesia]

Continuous spinal anaesthesia has a number of advantages, but there are a number of drawbacks as well: difficulties in threading the catheter, distribution of the local anaesthetics and the development of cauda equina syndrome. Spinaloscopy was done to visualize the fate of catheters during and after their insertion, as well as the distribution of local anaesthetics injected through these fine-bore catheters. METHOD. The studies were conducted in preserved and fresh cadavers donated to the Anatomic Institute for Medical Studies. The spinal column from T12 to S1, together with the back musculature (in order to preserve the normal curvature of the spine) were removed from the cadaver. Spinaloscopy was done with a 4 mm endoscope with a 0 degree optic (Storz, Tutlingen, FRG). All observations were made from the lumbosacral region of the dissected preparation. In this fashion, it was possible to observe the insertion of the spinal needle used to introduce the catheter into the subdural space. The distribution of local anaesthetics injected through a 22-gauge spinal needle or a 28-gauge catheter was shown by injecting 0.5% hyperbaric bupivacaine colored with a small amount of 1% methylene blue. Pictures were taken 15, 30 and 45 s after beginning the injection. RESULTS. Difficulty in threading the catheter: our observations indicate that the difficulty in inserting microbore catheters is most likely due to inserting the needle too far. It is impossible for the catheter to bend and be inserted into the subarachnoid space. In many cases the catheter encountered the anterior wall of the spinal canal and would slide along various structures. Distribution of the drug: the injection is better dispersed with a 22-gauge needle and it completely fills the subarachnoid space. The local anaesthetics injected through the 28-gauge nylon catheter (Kendall Healthcare, Mansfield, Mass.) are distributed in the dependent portions of the spinal canal. If high doses and a high concentration are injected, the distribution pattern may result in an overconcentration in some parts of the subarachnoid space. Possibility of trauma: the catheter stretches around the roots, the potential for trauma is that untoward stress may be applied to the root, either during full insertion of the catheter or during its withdrawal. CONCLUSION. Spinaloscopy was done in a non-fixated anatomic spinal column preparation with a 4 mm 0 degree endoscope (Storz, Tuttlingen, FRG). Based on our observations, we conclude: The catheter should only be inserted 2 cm into the subarachnoid space. This may decrease the risk of malpositioning. After the tip of the catheter has reached the subarachnoid space, the stylet should be with drawn 2 or 3 cm to minimize the risk of nerve injury and/or bleeding.

[CSE--the combination of spinal and epidural anesthesia]

The availability of very fine-bore, long spinal needles (28/10 Ga) has stimulated a new wave of interest in the technique of combined spinal-epidural anesthesia. The original double-puncture technique has progressed due to special combination needles to the current spinal-needle-through-epidural-needle technique. The availability of adapted Tuohy needles, special combination sets, and long spinal needles indicates a lack of standardization. An appropriate introduction technique via Tuohy needle allows identification of the anatomic landmarks and contributes to successful anesthesia. The spinal component allows a rapid onset and intense analgesia with appropriate muscle relaxation. The epidural catheter allows the administration of agents into the epidural space as well as optimization and prolongation of analgesia in the postoperative phase. Confirming the position of the epidural catheter introduced after spinal anesthesia has been established remains a matter of concern.

Erythropoietin in polycystic kidneys

Erythropoietin (EPO) formation in kidneys of 18 patients with autosomal dominant polycystic kidney disease (ADPKD) was investigated. In 12 patients on hemodialysis and in 6 patients with preterminal renal failure serum, EPO was 29 +/- 7 and 16 +/- 1.5 mU/ml and hemoglobin concentrations were 11.0 +/- 0.6 and 12.7 +/- 1.2 g/dl, respectively. Cyst fluid from a total of 357 renal cysts was obtained by either in vivo aspiration or immediately after nephrectomy. The cysts contained variable concentrations of bioactive EPO from undectable values up to 3.2 U/ml. A pronounced enrichment of EPO was observed in cysts with sodium concentrations greater than 100 mmol/liter, suggesting an association with proximal tubular malformations. The EPO concentrations in the cysts were neither correlated with the protein concentration nor with the oxygen pressure of the cyst fluid. Using a cDNA probe for human EPO, mRNA for EPO was localized in stroma cells of the cyst walls by an in situ hybridization technique. Our findings suggest that single interstitial cells juxtaposed to proximal tubular cysts may produce EPO independent of the oxygen pressure inside the cysts, which ameliorates the anemia during end-stage polycystic kidney disease.

[Duplex sonography in the diagnosis of renal artery stenoses following allogenic kidney transplantation]

Posttransplant renal artery stenosis (TRAS) as a cause of secondary hypertension is reported with an incidence of 1 to 10%. Early diagnosis of TRAS should be made by non-nephrotoxic and non-invasive means to lower the risk of hypertension. One to 66 months after kidney transplantation 335 patients underwent Duplex-scanning, 38 of cases for clinical tentative diagnosis of TRAS. Parameters for clinical diagnosis of TRAS were diastolic hypertension greater than 100 mm Hg with resistance to therapy (A), an abdominal bruit over the transplant (B), disturbance of renal function (serum-creatinine greater than 2 mg/dl) (C). Admission to study followed the parameter-combination A + B. A + C, B + C. Rejection crisis was excluded in 18/38 cases by fine needle biopsy, cyclosporine over-dosage was negative in 38/38 cases, 20/38 cases had normal renal function. Duplex-/Doppler-ultrasound criteria for TRAS were systolic peak velocity greater than 100 cm/s-1 and broadening of the diastolic frequency spectra with a smooth decline in diastole to an elevated diastolic level. In 32/38 cases (84.2%, n = 38) diagnosis of TRAS was made by duplex-scanning, angiography confirmed the result in 30/32 cases (93.75%, n = 32); sensitivity was 88.2% with a specificity of 66.6%. Duplex-scanning as a primary diagnostic means for TRAS seems a promising method compared to e.g. radionuclide imaging or angiography. Duplex-scanning is a non-nephrotoxic and non-invasive procedure repeatable at any time with only few preliminary conditions.(ABSTRACT TRUNCATED AT 250 WORDS)

[Catheter malposition following puncture of the left internal jugular vein]

A central venous catheter was inserted into the left internal jugular vein but was abnormally directed into a peripheral pulmonary vein. This could be explained by an anomalous pulmonary venous return to the superior vena cava.