Intraoperative blood loss as indicated by haemoglobin trend is a predictor for the development of postoperative spinal implant infection-a matched-pair analysis.

BACKGROUND: With a reported rate of 0.7-20%, postoperative spinal implant infection (PSII) is one of the most common complications after spine surgery. While in arthroplasty both haematoma formation and perioperative blood loss have been identified as risk factors for developing periprosthetic joint infections and preoperative anaemia has been associated with increased complication rates, literature on the aetiology of PSII remains limited. METHODS: We performed a matched-pair analysis of perioperative haemoglobin (Hb) and haematocrit (Hct) levels in aseptic and septic spine revision surgeries. 317 patients were included, 94 of which were classified as septic according to previously defined criteria. Patients were matched according to age, body mass index, diabetes, American Society of Anesthesiologists score and smoking habits. Descriptive summaries for septic and aseptic groups were analysed using Pearson chi-squared for categorical or Student t test for continuous variables. RESULTS: Fifty patients were matched and did not differ significantly in their reason for revision, mean length of hospital stay, blood transfusion, operating time, or number of levels operated on. While there was no significant difference in preoperative Hb or Hct levels, the mean difference between pre- and postoperative Hb was higher in the septic group (3.45 ± 1.25 vs. 2.82 ± 1.48 g/dL, p = 0.034). CONCLUSIONS: We therefore show that the intraoperative Hb-trend is a predictor for the development of PSII independent of the amount of blood transfusions, operation time, number of spinal levels operated on and hospital length of stay, which is why strategies to reduce intraoperative blood loss in spine surgery need to be further studied.

A new score for characterizing the visibility of anatomical structures during ultrasound guided regional anesthesia: a retrospective cohort study.

BACKGROUND: To identify anatomical structures using sonography can be challenging, yet it is a basic requirement for effective and safe ultrasound guided nerve blocks. In clinical routine, we find a wide variety in the visibility of anatomical structures. Aim of this study was to evaluate the feasibility of a newly developed visibility score for anatomical structures in ultrasound guided regional anesthesia. METHODS: We retrospectively evaluated the blockades from the routine documentation of ultrasound-guided regional anesthesia over an arbitrary period of 15 months at a university hospital with a Visibility Score (VIS) of one (best) to five (worst visibility). RESULTS: The study analyzed 983 blockades (femoral, saphenous, infragluteal and popliteal sciatic, transversus abdominis plane, interscalene, supraclavicular, axillary and suprascapular blockades). The following VIS were found: 1: 80.6%; 2: 14.0%; 3: 4.0%; 4: 1.2%; 5: 0.2%. The mean Body Mass Index (BMI) was 27.9 kg/m2. The best cut-off for poor VIS was a BMI of 28.9 kg/m2. For infragluteal sciatic nerve block VIS was significantly higher (mean VIS 1.71±1.0) compared to all the other recorded blockades except the supraclavicular block. CONCLUSIONS: VIS was feasible in clinical routine. Compared to the other evaluated blocks, the VIS for the infragluteal access to the sciatic nerve was rated worst. VIS is found to be worse in obese patients. Further research is needed to evaluate VIS and its suitability for specific questions as for instance anesthetists' learning curves, comparison of different patient populations, ultrasound devices or different nerve blocks.

The concept of protective nerve stimulation for ultrasound guided nerve blocks.

Regional plexus and nerve blocks are a common technique in modern anesthesia. Since ultrasound machines are available in many departments, the role of nerve stimulation is highly discussed and different approaches to perform the blocks are taken into account. Common technique for electrical nerve stimulation is searching for a stimulating threshold of 0.4-0.5mA using an impulse width of 0.1ms. We present our hypothesis of using all possible information with a new concept of protective nerve stimulation together with first data supporting our theory. In protective nerve stimulation during ultrasound guided nerve blocks a fixed current of 1.0mA (0.1ms) is used without any change during block performance. The aim is no muscular twitches before and during injection. If this way of neuro-axial blocking brings suitable effects, we should consider new currency settings to perform safer blockades with a lower risk of nerve injuries and a high patient comfort, especially in bad visibility block situations.

The combinations C1 esterase inhibitor with coagulation factor XIII and N-acetylcysteine with tirilazad mesylate reduce the leukocyte adherence in an experimental endotoxemia in rats.

The study's objective was to determine the effects of the administration of combinations of C1 esterase inhibitor (C1-INH) with coagulation factor XIII (F XIII) and N-acetylcysteine (NAC) with tirilazad mesylate (TM) on leukocyte adherence and on intestinal functional capillary density during experimental endotoxemia in rats. In a prospective, randomized, controlled animal study, 40 male Wistar rats were divided into 4 groups. Group 1 (CON group) served as control group. Group 2 (LPS group), group 3 (C1-INH+F XIII group) and group 4 (NAC+TM group) received endotoxin infusions (10 mg/kg/h for 2 h). In C1-INH+F XIII group, 100 U/kg b.w. C1-INH and 50 U/kg b.w. F XIII were administered after the first 30 min of endotoxemia. In the NAC+TM group, 150 mg/kg b.w. N-acetylcysteine and 10 mg/kg b.w. Tirilazad mesylate were administered after 30 min of endotoxemia. Leukocyte adherence at venules of the intestinal submucosal layer and functional capillary density in the villi intestinales and in the longitudinal and circular muscle layers were estimated by intravital fluorescence microscopy (IVM). C1-INH+F XIII reduced the count of firmly adherent leukocytes that was increased after LPS administration in the V3 venules (CON group 69 (17-160)/mm2; LPS group 635 (556-814)/mm2; C1-INH+F XIII group 503 (337-646)/mm2). NAC+TM reduced the firmly adherent leukocytes in the V3 venules (NAC+TM group 403 (309-572)/mm2) and in the V1 venules (CON group 55 (16-131)/mm2; LPS group 368 (306-475)/mm2; NAC+TM group 270 (216-308)/mm2) as well. FCD was not impaired after LPS challenge and there was no influence of both combinations on the FCD. We conclude that both drug combinations can reduce the leukocyte adherence in a sepsis model in rats.

Iloprost for additional anticoagulation in continuous renal replacement therapy--a pilot study.

PURPOSE: The aim of this pilot study was to compare the effect of heparin anticoagulation with and without iloprost administration during continuous renal replacement therapy (CRRT) in critically ill patients. MATERIAL AND METHODS: In a prospective, randomized, controlled pilot study at an intensive care unit at a university hospital, 20 patients requiring CRRT were investigated. Patients were allocated into two groups: group 1, the heparin group; and group 2, the heparin plus 1 ng/kg/min iloprost. In both groups, activated partial thromboplastin time (aPTT) was adjusted to 40-50 sec. Observation time was a maximum of 7 days. RESULTS: Median filter run time was significantly prolonged by iloprost administration to a median of 14 h (13-26 h) compared to 10 h (4-12 h) in the heparin group (p = 0.004). A decrease in platelet count was attenuated by iloprost administration (p = 0.012). There were no bleeding complications in either group. Hemofiltration efficiency did not differ significantly between the groups. CONCLUSION: Additional administration of iloprost prolonged the filter run time of continuous veno-venous hemofiltration (CVVH) in this setting and attenuated the fall in platelet count during CRRT.

Effects of dopexamine on the intestinal microvascular blood flow and leukocyte activation in a sepsis model in rats.

INTRODUCTION: The administration of dopexamine may constitute a therapeutical option to improve hepatosplanchnic perfusion in sepsis. In order to verify this hypothesis, we administered dopexamine in an experimental sepsis model in rats. METHODS: This prospective, randomized, controlled laboratory study was conducted in 42 Wistar rats. The animals were divided into 3 groups. Group 1 (CON group) served as control group. The Animals of groups 2 (LPS Group) and 3 received an endotoxin infusion (20 mg/kgfor 15 min). In addition, in group 3 (DPX group) dopexamine was administered 0.5 microg/kg/minover 4 hours. One half of the animals of each group underwent studies of intestinal microvascular blood flow (IMBF) using laser Doppler fluxmetry. In the other half an intravital microscopic evaluation of the leukocyte endothelium cell interaction in the intestinal microcirculation was performed. Functional capillary denstity (FCD) in the intestinal mucosaand the circular as well as the longitudinal muscle layer was estimated. RESULTS: One hour after endotoxin challenge IMBF decreased significantly in the untreated LPS group to 51% compared to baseline (p<0.05). In DPX treated endotoxin animals we found significantly higher values at the level of CON group. The after endotoxin challenge impaired FCD was improved by dopexamine in the longitudinal (DPX + 33% vs. LPS; p <0.05) and in the circular muscle layer (DPX + 48% vs. LPS; p < 0.05) as a result of dopexamine administration. The administration of dopexamine reduced the count of firmly adherent leukocytes when compared to the untreated LPS group (-31%, p<0.05). TNF-alpha plasma levels were reduced by dopexamine infusion (LPS group 3637 +/- 553 pg/mL; DPXgroup 1933 +/- 201 pg/mL) one hour after endotoxin challenge. CONCLUSIONS: The administration of dopexamine improved IMBF and FCD as parameters of intestinal microcirculation and reduced leukocyte activation as a parameter of inflammation in experimental sepsis.