[COVID-19 in obstetric anesthesia : Prospective surveillance of peripartum infections with SARS-CoV-2 and peripartum course of disease in affected women]. / COVID-19 in der geburtshilflichen Anästhesie : Prospektive Erfassung von SARS-CoV-2-Infektionen zum Zeitpunkt der Geburt sowie des peripartalen Verlaufs SARS-CoV-2-positiver Schwangerer.

BACKGROUND: In the current pandemic regarding the infection with the SARS-CoV-2-virus and COVID-19 as the disease, concerns about pregnant women, effects on childbirth and the health of the newborn remain high. Initially, due to the early manifestation of the disease in younger patients, high numbers of COVID-19 patients in women needing peripartum care were expected. OBJECTIVE: This article aims to provide a general overview over the beginning of the pandemic as well as the second wave of infections in Germany and Switzerland, regarding SARS-CoV­2 positive pregnant women hospitalized for childbirth. We therefore launched a registry to gain timely information over the dynamic situation during the SARS-CoV­2 pandemic in Germany. MATERIAL AND METHODS: As part of the COVID-19-related Obstetric Anesthesia Longitudinal Assessment (COALA) registry, centers reported weekly birth rates, numbers of suspected SARS-CoV­2 cases, as well as the numbers of confirmed cases between 16 March and 3 May 2020. Data acquisition was continued from 18 October 2020 till 28 February 2021. The data were analyzed regarding distribution of SARS-CoV­2 positive pregnant women hospitalized for childbirth between centers, calendar weeks and birth rates as well as maternal characteristics, course of disease and outcomes of SARS-CoV­2 positive pregnant women. RESULTS: A total of 9 German centers reported 2270 deliveries over 7 weeks during the first wave of infections including 3 SARS-CoV­2 positive cases and 9 suspected cases. During the second survey period, 6 centers from Germany and Switzerland reported 41 positive cases out of 4897 deliveries. One woman presented with a severe and ultimately fatal course of the disease, while another one needed prolonged ECMO treatment. Of the women 28 presented with asymptomatic infections and 6 neonates were admitted to a neonatal intensive care unit for further treatment. There was one case of neonatal SARS-CoV­2 infection. CONCLUSION: The number of pregnant women infected with SARS-CoV­2 was at a very low level at the time of delivery, with only sporadic suspected or confirmed cases. Due to the lack of comprehensive testing in the first survey period, however, a certain number of asymptomatic cases are to be assumed. Of the cases 68% presented as asymptomatic or as mild courses of disease but the data showed that even in young healthy patients without the presence of typical risk factors, serious progression can occur. These outcomes should raise awareness for anesthesiologists, obstetricians, pediatricians and intensive care physicians to identify severe cases of COVID-19 in pregnant women during childbirth and to take the necessary precautions to ensure the best treatment of mother and neonate. The prospective acquisition of data allowed a timely assessment of the highly dynamic situation and gain knowledge regarding this vulnerable group of patients.

Risks and Benefits of Ultrasound, Nerve Stimulation, and Their Combination for Guiding Peripheral Nerve Blocks: A Retrospective Registry Analysis.

BACKGROUND: Ultrasound, nerve stimulation, and their combination are all considered acceptable ways to guide peripheral nerve blocks. Which approach is most effective and associated with the fewest complications is unknown. We therefore used a large registry to analyze whether there are differences in vascular punctures, multiple skin punctures, and unintended paresthesia. METHODS: Twenty-six thousand seven hundred and thirty-three cases were extracted from the 25-center German Network for Regional Anesthesia registry between 2007 and 2016 and grouped into ultrasound-guided puncture (n = 10,380), ultrasound combined with nerve stimulation (n=8173), and nerve stimulation alone (n = 8180). The primary outcomes of vascular puncture, multiple skin punctures, and unintended paresthesia during insertion were compared with conditional logistic regression after 1:1:1 propensity score matching. Results are presented as odds ratios and 95% CIs. RESULTS: Propensity matching successfully paired 2508 patients with ultrasound alone (24% of 10,380 patients), 2508 patients with a combination of ultrasound/nerve stimulation (31% of 8173 patients), and 2508 patients with nerve stimulation alone (31% of 8180 patients). After matching, no variable was imbalanced (standardized differences <0.1). Compared with ultrasound guidance alone, the odds of multiple skin punctures (2.2 [1.7-2.8]; P < .001) and vascular puncture (2.7 [1.6-4.5]; P < .001) were higher with nerve stimulation alone, and the odds for unintended paresthesia were lower with nerve stimulation alone (0.3 [0.1-0.7]; P = .03). The combined use of ultrasound/nerve stimulation showed higher odds of multiple skin punctures (1.5 [1.2-1.9]; P = .001) and lower odds of unintended paresthesia (0.4 [0.2-0.8]; P = .007) compared with ultrasound alone. Comparing the combined use of ultrasound/nerve stimulation with ultrasound alone, the odds for vascular puncture (1.3 [0.7-2.2]; P = .4) did not differ significantly. Systemic toxicity of local anesthetics was not observed in any patient with ultrasound guidance alone, in 1 patient with the combined use of ultrasound and nerve stimulation, and in 1 patient with nerve stimulation alone. CONCLUSIONS: Use of ultrasound alone reduced the odds of vascular and multiple skin punctures. However, the sole use of ultrasound increases the odds of paresthesia.

Prolonged Catheter Use and Infection in Regional Anesthesia: A Retrospective Registry Analysis.

BACKGROUND: Prolonged catheter use is controversial because of the risk of catheter-related infection, but the extent to which the risk increases over time remains unknown. We thus assessed the time-dependence of catheter-related infection risk up to 15 days. METHODS: Our analysis was based on the German Network for Regional Anesthesia, which includes 25 centers. We considered 44,555 patients who had surgery between 2007 and 2014 and had continuous regional anesthesia as well as complete covariable details. Cox regression analysis was performed and adjusted for confounding covariables to examine the relationship between catheter duration and probability of infection-free catheter use. RESULTS: After adjustment for confounding factors, the probability of infection-free catheter use decreases with each day of peripheral and epidural catheter use. In peripheral catheters, it was 99% at day 4 of catheter duration, 96% at day 7, and 73% at day 15. In epidural catheters, it was 99% at day 4 of catheter duration, 95% at day 7, and 73% at day 15. Only 31 patients (0.07%) had severe infections that prompted surgical intervention. Among these were five catheters that initially had only mild or moderate signs of infection and were left in situ; all progressed to severe infections. CONCLUSIONS: Infection risk in catheter use increases over time, especially after four days. Infected catheters should be removed as soon as practical. VISUAL ABSTRACT: An online visual overview is available for this article at http://links.lww.com/ALN/B683.

Psoas Versus Femoral Blocks: A Registry Analysis of Risks and Benefits.

BACKGROUND AND OBJECTIVES: Psoas blocks are an alternative to femoral nerve blocks and have the potential advantage of blocking the entire lumbar plexus. However, the psoas muscle is located deeply, making psoas blocks more difficult than femoral blocks. In contrast, while femoral blocks are generally easy to perform, the inguinal region is prone to infection. We thus tested the hypothesis that psoas blocks are associated with more insertion-related complications than femoral blocks but have fewer catheter-related infections. METHODS: We extracted 22,434 surgical cases from the German Network for Regional Anesthesia registry (2007-2014) and grouped cases as psoas (n = 7593) and femoral (n = 14,841) blocks. Insertion-related complications (including single-shot blocks and catheter) and infectious complications (including only catheter) in each group were compared with χ tests. The groups were compared with multivariable logistic models, adjusted for potential confounding factors. RESULTS: After adjustment for potential confounding factors, psoas blocks were associated with more complications than femoral blocks including vascular puncture 6.3% versus 1.1%, with an adjusted odds ratio (aOR) of 3.6 (95% confidence interval [CI], 2.9-4.6; P < 0.001), and multiple skin punctures 12.6% versus 7.7%, with an aOR of 2.6 (95% CI, 2.1-3.3; P <0.001). Psoas blocks were also associated with fewer catheter-related infections: 0.3% versus 0.9% (aOR of 0.4; 95% CI, 0.2-0.8; P = 0.016), and with improved patient satisfaction (mean ± SD 0- to 10-point scale score, 9.6 ± 1.2 vs 8.4 ± 2.9; P < 0.001). Results from a propensity-matched sensitivity analysis were similar. CONCLUSIONS: Psoas blocks are associated with more insertion-related complications but fewer infectious complications. CLINICAL TRIAL REGISTRATION: ID NCT02846610.

[Hypercapnic Raised Intracerebral Pressure - Ecmo Therapy Despite Major Intracerebral Haemorrhage]. / Kasuistik: ECMO-Einsatz bei hyperkapnischer Hirndruckkrise.

We report a case of a 29-year-old primigravida asian woman with severe peripartal HELLP-syndrome. During delivery she developed coma. HELLP syndrome, complicated by severe intracerebral hemorrhage was detected. During course of therapy with drainage of intraventricular intracerebral hemorrhage, the patient developed pneumonia followed by severe acute respiratory distress syndrome (ARDS) with critically raised ICP. After 31 days of stabilization by extracorporeal membrane oxygenation (ECMO) and lung protective ventilation the patient was weaned of ECMO therapy. Following a period of 107 days including the weaning of respirator-therapy her neurologic status improved and she was able to follow commands, move upper and lower extremities on request, and recognize her relatives.

Single-dose Antibiotic Prophylaxis in Regional Anesthesia: A Retrospective Registry Analysis.

BACKGROUND: Catheter-related infection is a serious complication of continuous regional anesthesia. The authors tested the hypothesis that single-dose antibiotic prophylaxis is associated with a lower incidence of catheter-related infections. METHODS: Our analysis was based on cases in the 25-center German Network for Regional Anesthesia database recorded between 2007 and 2014. Forty thousand three hundred sixty-two surgical patients who had continuous regional anesthesia were grouped into no antibiotic prophylaxis (n = 15,965) and single-dose antibiotic prophylaxis (n = 24,397). Catheter-related infections in each group were compared with chi-square test after 1:1 propensity-score matching. Odds ratios (ORs [95% CI]) were calculated with logistic regression and adjusted for imbalanced variables (standardized difference more than 0.1). RESULTS: Propensity matching successfully paired 11,307 patients with single-dose antibiotic prophylaxis (46% of 24,397 patients) and with 11,307 controls (71% of 15,965 patients). For peripheral catheters, the incidence without antibiotics (2.4%) was greater than with antibiotic prophylaxis (1.1%, P < 0.001; adjusted OR, 2.02; 95% CI, 1.49 to 2.75, P < 0.001). Infections of epidural catheters were also more common without antibiotics (5.2%) than with antibiotics (3.1%, P < 0.001; adjusted OR, 1.94; 95% CI, 1.55 to 2.43, P < 0.001). CONCLUSIONS: Single-dose antibiotic prophylaxis was associated with fewer peripheral and epidural catheter infections.

Awake, sedated or anaesthetised for regional anaesthesia block placements?: A retrospective registry analysis of acute complications and patient satisfaction in adults.

BACKGROUND: Whether adults should be awake, sedated or anaesthetised during establishment of regional anaesthesia is still debated and there is little information on the relative safety of each. In paediatric practice, there is often little choice but to use sedation or anaesthesia as otherwise the procedures would be too distressing and patient movement would be hazardous. OBJECTIVE(S): The objective of this study was to evaluate complications related to central and peripheral regional block and patient satisfaction in awake, sedated and anaesthetised adult patients. DESIGN: A retrospective registry analysis. SETTING: The German Network of Regional Anaesthesia database was analysed between 2007 and 2012. PATIENTS: We included data of 42 654 patients and defined three groups: group I awake (n = 25 004), group II sedated (n = 15 121) and group III anaesthetised (n = 2529) for block placement. MAIN OUTCOME MEASURES: Odds ratios [OR; 95% confidence interval (CI)] were calculated with logistic regression analysis and adjusted for relevant confounders to determine the risk of block-related complications in sedated or anaesthetised patients compared with awake patients. RESULTS: Rates of local anaesthetic systemic toxicity were comparable between the groups [awake 0.02% (95% CI: 0.002 to 0.0375), sedated 0.02% (0.003 to 0.042) and anaesthetised 0% (0 to 0.12%)], as were the rates of pneumothorax [awake 0.035% (0 to 0.074), sedated 0% (0 to 0.002) and anaesthetised 0.2% (0 to 0.56)]. Considering peripheral nerve blocks, sedated patients had a decreased risk for multiple skin puncture [adjusted OR: 0.78 (95% CI: 0.71 to 0.85), premature termination [0.45 (0.22 to 0.91)], primary failure [0.58 (0.40 to 0.83)] and postoperative paraesthesia [0.35 (0.28 to 0.45)], but an increased risk for a bloody tap [1.82 (1.50 to 2.21)]. General anaesthesia increased the risk of a bloody tap [adjusted OR: 1.33 (95% CI: 1.01 to 1.78)] and multiple skin puncture [1.28 (1.12 to 1.46)], but decreased the risk for postoperative paraesthesia [0.16 (0.06 to 0.38)]. In neuraxial sites, sedation increased the risk for multiple skin puncture [adjusted OR: 1.18 (95% CI: 1.09 to 1.29)], whereas block placement under general anaesthesia decreased the risk for multiple skin puncture [0.53 (0.39 to 0.72)] and bloody tap but significantly increased the risk for postoperative paraesthesia related to a catheter [2.45 (1.19 to 5.02)]. Sedation was associated with a significant improvement in patient satisfaction. CONCLUSION: Sedation may improve safety and success of peripheral nerve block placement. Block placement under general anaesthesia in adults should be reserved for experienced anaesthesiologists and special situations.

Diabetes: a risk factor for catheter-associated infections.

BACKGROUND AND OBJECTIVES: The incidence of infectious complications associated with continuous regional anesthesia techniques is a matter of concern. Our objective was to determine whether patients suffering from diabetes are at an increased risk of catheter-related infectious complications. METHODS: The German Network for Regional Anaesthesia database was analyzed between 2007 and 2012. After proof of plausibility, data of 36,881 patients undergoing continuous regional anesthesia were grouped in I: no diabetes (n = 32,891) and II: any diabetes (n = 3990). The analysis focused on catheter-related infections after strict definition. Differences among the groups were tested with t and χ tests. Odds ratios were calculated with logistic regression and adjusted for potential confounders. RESULTS: Patients with a diagnosis of diabetes had an increased incidence of catheter-related infections (no diabetes 3.0% vs any diabetes 4.2%; P < 0.001). Among all patients, diabetes remained an independent risk factor for infections for all sites after the adjustment for potential confounders (odds ratio [OR] = 1.26; 95% confidence interval [95% CI], 1.02-1.55; P = 0.036). The risk of infection was significantly increased in peripheral catheters only in the lower limb (adjusted OR = 2.42; 95% CI, 1.05-5.57; P = 0.039). If neuraxial catheters were used, the risk was significantly increased only in lumbar epidural (adjusted OR = 2.09; 95% CI, 1.18-3.73; P = 0.012) for diabetic patients compared with nondiabetic patients. CONCLUSIONS: The presence of diabetes is associated with an increased risk for catheter-related infections in lower limb and lumbar epidural. Specific care should be taken to avoid and detect infections in this population.

Spinal anesthesia protects against perioperative hyperglycemia in patients undergoing hip arthroplasty.

STUDY OBJECTIVE: To determine whether spinal anesthesia blunts surgical stress reactions and results in less perioperative hyperglycemia. DESIGN: Prospective, randomized controlled study. SETTING: Operating room of a university hospital. PATIENTS: 68 adult, nondiabetic (n = 40) and diabetic (n = 28), ASA physical status 1, 2, and 3 patients patients undergoing elective total hip replacement. INTERVENTIONS: General or spinal anesthesia was administered. MEASUREMENTS: Blood HbA1C was measured preoperatively to identify patients with undiagnosed diabetes. Glucose levels were checked preoperatively, then immediately after, and one hour after surgery. A conventional glucose control protocol was used, where insulin was given when blood glucose concentrations exceeded 250 mg/dL. MAIN RESULTS: Preoperative glucose levels in general and spinal anesthesia patients were comparable and not significantly different in nondiabetic and diabetic patients. At the end of surgery and one hour after surgery, glucose levels were significantly higher in patients undergoing general anesthesia compared with baseline values in both diabetic and nondiabetic patients (P < 0.05). In nondiabetic and diabetic patients, a significant increase in glucose level was found in patients undergoing general anesthesia versus spinal anesthesia (P < 0.05). In patients receiving spinal anesthesia, glucose levels remained stable. Two diabetic patients undergoing general anesthesia received insulin. CONCLUSION: Spinal anesthesia attenuates the hyperglycemic response to surgical stimuli in diabetics and nondiabetic patients.

What do patients know about anesthesiologists? Results of a comparative survey in an U.S., Australian, and German university hospital.

STUDY OBJECTIVES: To determine patients' knowledge of the role of the anesthesiologist in the hospital. DESIGN: Prospective survey instrument. SETTING: Three university hospitals (University of Virginia, Charlottesville, VA, USA; St. George Hospital University of New South Wales, Sydney, Australia; and University Hospital, Ruhr-University Bochum, Bochum, Germany). PATIENTS: 900 patients (300 pts per center) undergoing elective surgery. MEASUREMENTS: Patients completed a standardized questionnaire before surgery and before speaking to an anesthesiologist. MAIN RESULTS: Most patients knew that anesthesiologists were medical doctors (Charlottesville, 58%; Bochum, 83%; Sydney, 71%). The majority (> 75%) underestimated the amount of training required to become anesthesiologist. While patients recognized the role of anesthesiologists in keeping patients asleep and awakening them, many patients did not understand the anesthesiologists' role in treating intraoperative medical problems. Patients had diverse concerns including infection, awakening during surgery, and failure to awaken, although patients were unclear about who was responsible for treating these issues. Outside the operating room (OR), 71% of patients rated Intensive Care Unit treatment as a duty of the anesthesiologist in Bochum, but fewer (P < 0.05) did so from Charlottesville (42%) and Sydney (49%). Understanding of duties outside the OR (resuscitation, teaching medical students, or chronic pain treatment) was very low (< 50%) in all centers. CONCLUSION: Patients underestimated the training and role of the anesthesiologist in the OR and hospital.

Is anesthesia dangerous?

BACKGROUND: Recent years have seen a rise in overall anesthesia-related mortality. METHOD: Selective review of the literature. RESULTS: Anesthesia-related mortality has fallen from 6.4/10 000 in the 1940s to 0.4/100 000 at present, largely because of the introduction of safety standards and improved training. The current figure of 0.4/100 000 applies to patients without major systemic disease; mortality is higher among patients with severe accompanying illnesses, yet in this group, too, perioperative mortality can be reduced by appropriate anesthetic management. Moreover, the use of regional anesthesia can also improve the outcome of major surgery. CONCLUSION: A recent increase in the percentage of older and multimorbid patients among persons undergoing surgery, along with the advent of newer types of operation that would have been unthinkable in the past, has led to an apparent rise in anesthesia-associated mortality, even though the quality of anesthesiological care is no worse now than in the past. On the contrary, in recent years, better anesthetic management has evidently played an important role in improving surgical outcomes.

[Regional anaesthesia and organ protection--the role of thoracic epidural anaesthesia]. / Perioperative Organprotektion - Regionalanästhesie: Die Rolle der thorakalen Epiduralanästhesie.

Epidural anaesthesia results in a significant reduction of postoperative pain, opioid requirement and opioid related side effects. Additionally a reduction of duration of postoperative ileus and pulmonary complication has been shown, but influence on cardiac morbidity remains contradictory. Effects on mortality and long term outcome after tumor surgery is still a topic of intensive research. Positive effects of epidural anaesthesia should be intensively used in terms of intensive physiotherapy and postoperative mobilisation as well as early enteral nutrition to further improve outcome of the patients.

Failed induction of heme oxygenase 1 in endothelial cells exposed to the hemoglobin based oxygen carrier Oxyglobin.

We investigated the effect of the bovine hemoglobin based oxygen carrier HBOC-200 (Oxyglobin) in rat aortic endothelial cells (RAEC) on the activation of heme oxygenase 1 (HO-1). RAEC were incubated in the presence of 75 microM (G1) or 225 microM (G2) HBOC-200. The positive control (G3) was performed by incubation with 50 microM Hemin. For negative control (G4) cells were incubated with medium alone. G2 and G3 reached a significant increase of bilirubin concentration compared to G4. A positive HO-1 signal in the Western Blot was seen in G3 12 and 24 h after incubation. The Western Blot of G1, G2 and G4 showed no HO-1 signal. These data suggest that HBOC-200 in the applied dosage cannot induce HO-1 expression in RAEC, and may be degraded by isoenzymes at a lower level.

[Epidural anesthesia: step by step to success]. / Epiduralanästhesie: Schritt für Schritt zum Erfolg.

Besides pain management in obstetric patients epidural anaesthesia plays a major role in the perioperative setting. Especially the technique of thoracic epidural anaesthesia (TEA) provides better postoperative analgesia when compared with systemic pain therapy. TEA is associated with improved outcome in high-risk patients and patients undergoing extensive surgery. An acute pain management service is required to guarantee high effectiveness and a low complication rate. TEA is an important part of a multimodal perioperative concept, especially in fast-track surgery, which means advantages for patients outcome and hospitals economics.

Improvement of impaired microcirculation and tissue oxygenation by hemodilution with hydroxyethyl starch plus cell-free hemoglobin in acute porcine pancreatitis.

AIMS: To avoid the progression from mild edematous acute pancreatitis (AP) to the severe necrotizing form, one therapeutic option is to improve pancreatic microcirculation and tissue oxygenation. The aim of the study was to evaluate the influence of improved rheology (isovolemic hemodilution) plus enhanced oxygen supply (bovine hemoglobin HBOC-301) on pancreatic microcirculation, tissue oxygenation and survival in severe acute experimental pancreatitis. METHODS: Severe AP was induced in 39 pigs (25-30 kg BW) by stimulation with intravenous administration of cerulein plus a pressure- and volume-controlled 10-min intraductal infusion of glycodeoxycholic acid. Seventy-five minutes after induction of AP, animals were randomized and hemodiluted isovolemically (PAOP constant) with either 10% hydroxyethyl starch (HES) 200,000/0.5 plus HBOC-301 (+0.6 g/dl plasmatic hemoglobin; Oxyglobin, Biopure, Cambridge, Mass., USA), or 10% HES 200,000/0.5, or Ringer's solution to a hematocrit of 15%. Hemodynamics, oxygen transport parameters, pancreatic microcirculation and tissue oxygen tension were evaluated over 6 h. Then the abdomen was closed, animals were extubated and observed for 6 days. After that, the surviving animals were sacrificed and specimens were taken from the pancreas. The histopathologic findings were scored by two blinded pathologists who quantified acinar necrosis, fat necrosis, inflammation and edema. RESULTS: Isovolemic hemodilution with HES plus HBOC-301 reduced mortality and preserved pancreatic microcirculation compared with Ringer's solution, but was not significantly different from hemodilution with HES alone. Only treatment with HES plus HBOC-301 normalized pancreatic tissue oxygen tension compared with IHD with HES or Ringer's solution alone. CONCLUSIONS: IHD with HES plus HBOC-301 as a combination of rheologic and O(2)-delivering therapy may represent a novel therapeutic option for treatment of AP.

Influence of the hemoglobin solution HBOC-201 on tissue oxygenation in the rat R1H-tumor.

BACKGROUND: HBOC-201 is an ultra purified bovine hemoglobin solution. It has already been used in clinical phase II/III trials for emergency treatments. Animal experiments have shown that HBOC-201 is highly effective in tissue oxygenation. The study was performed in order to assess the potential of low dose HBOC-201 to improve tumor oxygenation. METHODS: 30 rats with a subcutaneously growing rhabdomyosarcoma R1H tumor were randomly assigned either to be ventilated with carbogen (n = 10), or to receive an IV injection of 0.3 g/kg HBOC-201 (n = 10) or a combination of 0.3 g/kg HBOC-201 and carbogen breathing (n = 10). Under general anesthesia the effects of the respective treatment on the tissue oxygen tension (tpO2) of the tumor were determined using a flexible stationary probe at baseline (b) and 15 and 60 min after application of the respective medication. RESULTS: HBOC-201 alone failed to improve tumor tpO2 (b: 1.3 +/- 1.2mmHg; 15min: 1.4 +/- 1 mmHg; 60min: 1 +/- 1 mmHg). In combination with carbogen the mean tpO2 of the tumor raised in comparison to baseline values (b: 3.1 +/- 4.6 mmHg; mmHg; 15min: 8.5 +/- 11*mmHg; 60min: 4.8 +/- 5mmHg; *p < 0.05 vs. b), but this effect was less pronounced than the increase in tpO2 by carbogen alone (b: 3.4 +/- 3.4mmHg; 15min: 9 +/- 10* mmHg; 60 min: 13 +/- 19* mmHg; *p < 0.05 vs. b). CONCLUSION: The application of low dose hemoglobin solution HBOC-201 does not result in improvement of tissue oxygenation in the rat rhabdomyosarcoma R1H.

No effect of the hemoglobin solution HBOC-201 on the response of the rat R1H tumor to fractionated irradiation.

BACKGROUND AND PURPOSE: Tumor hypoxia is regarded as one important underlying feature of radioresistance. The authors report on an experimental approach to improve tumor response to radiation by combining fractionated irradiation with HBOC-201, an ultrapurified polymerized hemoglobin solution, which is currently used in clinical phase II/III trials as alternative oxygen carrier and proved to be highly effective in tissue oxygenation (tpO(2)). MATERIAL AND METHODS: Subcutaneously growing rhabdomyosarcoma R1H tumors of the rat were treated with either 40 Gy (2 Gy/fraction, 20 fractions in 2 weeks, ambient) followed by graded top-up doses (clamped) alone, or in combination with HBOC-201, or with HBOC-201 plus carbogen (95% O(2) + 5% CO(2)). Local tumor control (TCD50%) and growth delay were used as endpoints. In addition, the effect of HBOC-201 alone or in combination with carbogen on the tpO(2) of tumor and muscle was determined using a flexible stationary probe (Licox, GMS). RESULTS: TCD50% values of 119 Gy (95% confidence interval 103;135), 111 Gy (84;138), and 102 Gy (83;120) were determined for tumors irradiated alone, in combination with HBOC-201, and with HBOC-201 plus carbogen, respectively. Although the dose-response curves showed a slight shift to lower doses when HBOC-201 or HBOC-201 plus carbogen was added, the differences in TCD50% were not statistically significant. No effect was seen on the growth delay of recurrent tumors. HBOC-201 alone did not effect tumor or muscle tpO(2). In combination with carbogen the mean tpO(2) of muscle raised from 23.9 mmHg to 59.3 mmHg (p < 0.05), but this effect was less pronounced than the increase in tpO(2) by carbogen alone. CONCLUSION: Low-dose application of HBOC-201 does not improve the response of the rhabdomyosarcoma R1H of the rat to fractionated irradiation.

Enhanced central organ oxygenation after application of bovine cell-free hemoglobin HBOC-201.

PURPOSE: While the effects of dilutional anemia or isovolemic hemodilution (IHD) on the oxygen extraction and tissue oxygenation in peripheral organs after application of hemoglobin-based oxygen carriers like HBOC-201 have been studied intensively, little is known about tissue oxygenation properties of hemoglobin solutions in central organs like the liver. METHODS: Twelve Foxhounds were anesthetized and then randomized to either a control group without hemodilution (Group 1) or underwent first step isovolemic hemodilution (pulmonary artery occlusion pressure constant) with Ringer's solution (Group 2) to a hematocrit of 25% with second step infusion of HBOC-201 until a hemoglobin concentration of +0.6 g.dL(-1) was reached. Tissue oxygen tensions (tpO2) were measured in the gastrocnemius muscle using a polarographic needle probe, and in the liver using a flexible polarographic electrode. RESULTS: While arterial oxygen content and oxygen delivery decreased with hemodilution in Group 2, global liver and muscle oxygen extraction ratio increased after hemodilution and additional application of HBOC-201. Hemodilution and application of HBOC-201 provided augmentation of the mean liver tpO2 (baseline: 48 +/- 9, 20 min: 53 +/- 10, 60 min: 67 +/- 11*, 100 min: 68 +/- 7*; *P < 0.05 vs baseline and Group 1), while oxygen tensions in Group 1 remained unchanged. Oxygen tension in the skeletal muscle increased after hemodilution and additionally after application of HBOC-201 in comparison to baseline and to the control group (P < 0.05). CONCLUSION: In the present animal model, IHD with Ringer's solution and additional application of HBOC-201 increased oxygen extraction and tpO(2) in the liver and skeletal muscle, in parallel and in comparison with baseline values and a control group.

A retrospective comparison of costs for regional and general anesthesia techniques.

In this retrospective study, we compared the costs for three different regional anesthesia techniques with the costs of general anesthesia (GA). A total of 1587 anesthesia cases which were performed for orthopedic and trauma patients over a 1-yr period in a tertiary level, university hospital setting were analyzed. The anesthesia technique-related costs were determined calculating case-specific costs for personnel, supplies, and drugs. The techniques were compared on the basis of anesthesia costs and surgical procedure duration. As a result, we found that the costs per surgical minute largely depend on the surgical procedure duration. Based on the regression function, the cost advantage of spinal anesthesia over GA can be estimated to be 13% for a 50-min case, 9% for a 100-min case, and 5% for a 200-min case. The cost disadvantage of brachial plexus anesthesia over GA can be estimated to be 19% for a 50-min case, 8% in a 100-min case, and 1% for a 200-min case. We found no difference in costs between epidural and GA. We concluded that cost comparisons of anesthesia techniques largely depend on the surgical duration of the cases studied. Even in a teaching hospital setting, spinal anesthesia has economic advantages over GA. Especially for short cases, brachial plexus block is more expensive in this setting.