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Adequate intraoperative infusion therapy is essential for the perioperative outcome of a patient. Both hypo- and hypervolemia can lead to an increased rate of perioperative complications and to a worse outcome. Perioperative infusion therapy should therefore be needs-based. The primary objective is the maintenance of preoperative normovolemia using a rational infusion strategy. Perioperative fluid losses should be differentiated from volume losses due to surgical bleeding or protein losses into the interstitial space. Fluid loss via urine excretion or insensible perspiration (0.5-1.0 ml/kg/h) should be replaced with balanced, isooncotic, crystalloid infusion solutions in a ratio of 1:1. Volume therapy stage 1: intraoperative volume losses up to a blood loss corresponding to 20% of the patient's total blood volume are compensated for by balanced crystalloids in a ratio of 4-5:1. Stage 2: blood losses exceeding this level are to be treated with isooncotic colloids (preferably balanced) in a 1:1 ratio. In this regard taking into consideration the contraindications, e. g., sepsis, burns, critical illness (usually patients in the intensive care unit), impaired renal function or renal replacement therapy, intracranial hemorrhage, or severe coagulopathy, artificial colloids such as hydroxyethyl starch (HES) can be used perioperatively for volume replacement. Stage 3: if an allogeneic blood transfusion is indicated, blood and blood products are applied in a differentiated manner. [ABSTRACT FROM AUTHOR]

Background/Objectives: The perioperative interplay between blood pressure, vasopressors, and macrocirculation is well established. However, in the context of free flap surgery, the potential impact of these factors on microvascular flow remains elusive. The aim was to evaluate the impact of norepinephrine administration on the microcirculation of free flaps. Methods: Postoperative systolic blood pressure (sBP), norepinephrine infusion rates (NIRs), and free flap microcirculation were monitored prospectively and analyzed retrospectively in patients receiving free flap surgery who required postoperative intermediate (IMC) or intensive care (ICU). Blood flow, hemoglobin oxygenation (SO 2 ), and relative hemoglobin levels (rHbs) were measured over a period of 24 hours post-anastomosis by laser-doppler flowmetry and white light spectroscopy using the "Oxygen to See" device (O2C, LEA Medizintechnik, Gießen, Germany). Multivariate analysis was performed to determine the impact of NIR on microvascular flow, adjusting for several confounding factors. Subgroup analysis was conducted by categorizing into three groups based on patients' postoperative sBP. Results: Flaps were performed in 105 patients with a mean age of 61.46 ± 16.29 years. Postoperatively, an increase in microvascular flow over time was observed across all free flaps, while NIR decreased and sBP maintained stable values. Multivariate analysis revealed that the time post-anastomosis (B = 3.76, p < 0.001), SO 2 (B = 0.55, p < 0.001), rHb (B= -0.79, p < 0.001), female gender (B = 29.25, p = 0.02), and no previous radiation therapy (B = 41.21, p = 0.04) had a significant impact on postoperative microvascular flow in free flaps. NIR, sBP, smoking status, old age, and ASA score showed no significant impact on free flap flow. Further, NIR showed no significant impact on microvascular flow in any of the subgroups investigated. Conclusions: These findings support the safety of using norepinephrine for maintaining stable blood pressure without compromising microvascular flow, offering valuable guidance for postoperative management., Competing Interests: The authors declare no conflict of interest.

Objective: Postoperative nausea and vomiting (PONV) occurs in up to 30% of patients and its pathophysiology and mechanisms have not been completely described. Hypotension and a decrease in cardiac output are suspected to induce nausea. The hypothesis that intraoperative hypotension might influence the incidence of PONV was investigated., Material and Methods: The study was conducted as a retrospective large single center cohort study. The incidence of PONV was investigated until discharge from post anesthesia care unit (PACU). Surgical patients with general anesthesia during a 2-year period between 2018 and 2019 at a university hospital in Germany were included. Groups were defined based on the lowest documented mean arterial pressure (MAP) with group H50: MAP <50mmHg; group H60: MAP <60mmHg; group H70: MAP <70mmHg, and group H0: no MAP <70mmHg. Decreases of MAP in the different groups were related to PONV. Propensity-score matching was carried out to control for overlapping risk factors., Results: In the 2-year period 18.674 patients fit the inclusion criteria. The overall incidence of PONV was 11%. Patients with hypotension had a significantly increased incidence of PONV (H0 vs. H50: 11.0% vs.17.4%, Risk Ratio (RR): 1.285 (99%CI: 1.102-1.498), p  < 0.001; H0 vs. H60: 10.4% vs. 13.5%, RR: 1.1852 (99%CI: 1.0665-1.3172), p  < 0.001; H0 vs. H70: 9.4% vs. 11.2%, RR: 1.1236 (99%CI: 1.013 - 1.2454); p  = 0.0027)., Conclusion: The study demonstrates an association between intraoperative hypotension and early PONV. A more severe decrease of MAP had a pronounced effect.

Background: Due to a multicenter study early in the coronavirus disease (COVID)-pandemic that revealed an increased risk for postoperative mortality, thromboembolic and pulmonary complications in case of surgery shortly after a COVID infection, current recommendations for planning elective surgeries suggest postponing surgery for at least 7 weeks after COVID infection. However, virus variants have evolved throughout the pandemic, leading to less severe symptoms. Besides, laparoscopic adrenal gland surgery itself is a safe procedure with low morbidity rates. Therefore, this study aimed to compare the perioperative course of patients undergoing laparoscopic adrenalectomy shortly after a COVID-19 infection with those who had not had a recent SARS-CoV-2 infection in 2022., Patients, Material, and Methods: All patients who underwent laparoscopic adrenalectomy at the Department for General, Visceral and Transplantation Surgery at Ludwig-Maximilian University between January and December 2022 were included., Results: There was no event of thromboembolic or pulmonary complications in the study population. Duration of surgery did not differ between the two groups; neither did the need for postoperative ICU-admittance nor the duration of ICU-stay. Intraoperative FiO 2 did not differ, nor did the SpO 2 or the number of different catecholamines. There was a slight trend towards higher noradrenaline dosage among patients after COVID-19 infection. Previous COVID infection did not lead to prolonged hospital stays., Conclusion: The results demonstrate that in case of well-standardized surgical procedures, with a limited surgical trauma and the possibility for patients to be mobilized early, surgery shortly after a mild COVID infection seems safe and reasonable., Competing Interests: The authors declare that they have no conflict of interest., (Thieme. All rights reserved.)

Introduction: Postoperative cognitive dysfunction (POCD) occurs in up to 26% of patients older than 60 years 1 week after non-cardiac surgery. Intraoperative beach chair positioning (BCP) is advantageous for some types of shoulder surgery. However, this kind of positioning leads to a downward bound redistribution of blood volume, with possible hypoperfusion of the brain. We hypothesized that patients > 60 years undergoing orthopaedic shoulder surgery in a BCP might experience more POCD than patients operated in the supine position (SP)., Material and Methods: A single-centre, prospective observational trial of 114 orthopaedic patients was performed. Study groups were established according to the type of intraoperative positioning. Anaesthesiological management was carried out similarly in both groups, including types of anaesthetics and blood pressure levels. POCD was evaluated using the Trail Making Test, the Letter-Number Span and the Regensburger Word Fluency Test. The frequency of POCD 1 week after surgery was considered primary outcome., Results: Baseline characteristics, including duration of surgery, were comparable in both groups. POCD after 1 week occurred in 10.5% of SP patients and in 21.1% of BCP patients (p = 0.123; hazard ratio 2.0 (CI 95% 0.794-5.038)). After 4 weeks, the incidence of POCD decreased (SP: 8.8% vs. BCP: 5.3%; p = 0.463). 12/18 patients with POCD showed changes in their Word Fluency Tests. Near-infrared spectroscopy (NIRS) values were not lower in patients with POCD compared to those without POCD (54% (50/61) vs. 57% (51/61); p = 0.671)., Conclusion: POCD at 1 week after surgery tended to occur more often in patients operated in beach chair position compared to patients in supine position without being statistically significant., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Adverse interactions between intravenous medications which are given simultaneously are a common problem in intensive care medicine. They are usually caused by administering a high number of medications over a limited number of intravenous lines or central venous catheters; however, this issue also arises in routine anesthetic procedures during surgery. The following case report highlights a so far undocumented interaction between the combination of theodrenaline/cafedrine and various antibiotics.Laparoscopic cholecystectomy was performed in a female patient, classified as ASA 1. After induction of general anesthesia 2 g ceftriaxone were administered as a perioperative antibiotic prophylaxis. Simultaneously, i.e. prior to the beginning of surgery, a mild decrease in blood pressure was observed and 2 ml diluted Akrinor® (2 ml theodrenaline/cafedrine + 8 ml NaCl 0.9%) was administered. Directly following this administration a chemical precipitation reaction occurred, and large white pasty flakes were noticed in the intravenous line. The infusion was stopped immediately and all lines were replaced.In order to confirm a causal relationship between the observed precipitation and the simultaneous administration of the two drugs, an in vitro test was performed by mixing Akrinor® with other preparations of cephalosporin antibiotics. The effect observed with ceftriaxone was reproducible and cefazoline also caused a precipitation reaction., (© 2022. The Author(s).)

Background: Body core temperature is an important vital parameter during surgery and anaesthesia. It is influenced by several patient-related and surgery-related factors. Laparoscopy is considered beneficial in terms of a variety of parameters, for example, postoperative pain and length of hospital stay. Non-humidified, non-warmed insufflated CO 2 applied during laparoscopy is standard of care. This prospective observational trial therefore evaluates the impact of non-humidified CO 2 at room temperature on abdominal temperature and its correlation to body core temperature., Methods: Seventy patients undergoing laparoscopic surgery were included in this prospective observational study. Temperature was measured oesophageal and abdominal before induction of anaesthesia (T1), right before skin incision (T2), 15 min, 30 min and 60 min after skin incision. All patients were treated according to actual guidelines for perioperative temperature measurement., Results: Body core temperature and abdominal temperature correlated moderately (r = 0.6123; p < 0.0001). Bland-Altman plot for comparison of methods showed an average difference of 0.4 °C (bias - 0.3955; 95% agreement of bias from - 2.365 to 1.574). Abdominal temperature further decreased after establishing pneumoperitoneum (T2: 36.2 °C (35.9/36.4) to T5: 36.1 °C (35.6/36.4); p < 0.0001), whereas oesophageal temperature increased (T2: 36.2 °C (35.9/36.4) to 36.4 °C (36.0/36.7); p = 0.0296). Values of oesophageal and abdominal measurement points differed at T4 (36.3 °C (36.0/36.6) vs. 36.1 °C (35.4/36.6); p < 0.0001) and T5 (36.4 °C (36.0/36.7) vs. 36.1 °C (35.6/36.4) p = 0.0003)., Conclusion: This prospective observational trial shows the influence of insufflated, non-humidified carbon dioxide at room temperature on abdominal temperature during laparoscopic surgery. We show that carbon dioxide applied at these conditions decreases abdominal temperature and therefore might be a risk factor for perioperative hypothermia., (© 2020. The Author(s).)

Objective: To identify risk factors for postoperative delirium (POD) after general oral and maxillofacial surgery., Material and Methods: 2420 patients were screened postoperatively for POD using the Nursing Delirium Screening Scale (NuDESC) before discharge from the post anesthesia caring unit (PACU). Basic health data and risk factors were collected. For analysis the study group (n=41) was compared to a control group of 164 randomly selected patients (case-control-ratio=1:4). To identify risk factors for POD multivariable logistic regression models were used. To see whether estimations remain stable, regression analysis was repeated for the subgroup of patients not undergoing dentoalveolar surgery (n=105). To estimate the risk for dentoalveolar surgery a logistic regression model was performed., Results: Dementia was the only significant risk factor for POD (Odds ratio 41.5; 95% CI 5.48-314), also for patients undergoing other than dentoalveolar surgery (58.1; 1.70-1983). Patients undergoing dentoalveolar surgery were more often suffering from dementia (35.5; 2.85-441), other psychiatric and neurological disorders (3.15; 1.05-9.43), were of younger age (0.97; 0.94-1.00) and had higher anesthesiological risk (3.95; 1.04-14.9)., Conclusion: Patients with dementia are at higher risk to develop POD after oral and maxillofacial surgery. We found a strong interdependence between age, dementia, ASA-Score and dentoalveolar surgery., (Copyright © 2020. Published by Elsevier Masson SAS.)

Background and Objectives: Delirium is a common and major complication subsequent to cardiac surgery. Despite scientific efforts, there are no parameters which reliably predict postoperative delirium. In delirium pathology, natriuretic peptides (NPs) interfere with the blood-brain barrier and thus promote delirium. Therefore, we aimed to assess whether NPs may predict postoperative delirium and long-term outcomes. Materials and Methods: To evaluate the predictive value of NPs for delirium we retrospectively analyzed data from a prospective, randomized study for serum levels of atrial natriuretic peptide (ANP) and the precursor of C-type natriuretic peptide (NT-proCNP) in patients undergoing coronary artery bypass grafting (CABG) with or without cardiopulmonary bypass (off-pump coronary bypass grafting; OPCAB). Delirium was assessed by a validated chart-based method. Long-term outcomes were assessed 10 years after surgery by a telephone interview. Results: The overall incidence of delirium in the total cohort was 48% regardless of the surgical approach (CABG vs. OPCAB). Serum ANP levels >64.6 pg/mL predicted delirium with a sensitivity (95% confidence interval) of 100% (75.3-100) and specificity of 42.9% (17.7-71.1). Serum NT-proCNP levels >1.7 pg/mL predicted delirium with a sensitivity (95% confidence interval) of 92.3% (64.0-99.8) and specificity of 42.9% (17.7-71.1). Both NPs could not predict postoperative survival or long-term cognitive decline. Conclusion s : We found a positive correlation between delirium and preoperative plasma levels of ANP and NT-proCNP. A well-powered and prospective study might identify NPs as biomarkers indicating the risk of delirium and postoperative cognitive decline in patients at risk for postoperative delirium., Competing Interests: The authors declare no conflict of interest.

Background: Intravenous fluids can impair coagulation and affect the endothelial glycocalyx, whereas glycocalyx shedding itself can cause an impairment of clot formation and firmness. We hypothesized that hydroxyethyl starch 6% (130/0.4) has a more distinct effect on coagulation and glycocalyx shedding than albumin 5%., Methods: Presented data derive from an exploratory subgroup analysis of a prospective randomized, single-blinded trial comparing albumin 5% versus balanced hydroxyethyl starch 6% (130/0.4). Patients between 46 and 85 years undergoing cystectomy were included. Prothrombin time, plasma fibrinogen concentration, partial thromboplastin time, thrombelastometry and platelet function were analyzed before and after surgery. Glycocalyx components were assessed before and after surgery, 2 to 4 h after surgery and at 1st and 3rd postoperative day. Primary outcome parameter was the change of thrombelastometric variables at the end of surgery. Further variables included calculated blood loss, infusion amount and transfusion rate., Results: 55 patients (albumin group n = 28; hydroxyethyl starch group n = 27) were included. Thrombelastometric variables were significantly more compromised in the hydroxyethyl starch than in the albumin group whereas platelet function, glycocalyx shedding, partial thromboplastin time, prothrombin time and fibrinogen were not different between groups. Mean intraoperative calculated blood loss was higher in the hydroxyethyl starch group (1557 ± 825 ml versus 1245 ± 709 ml; p = 0.042). Transfusion requirements did not differ., Conclusion: Rotational thrombelastometric variables were significantly more reduced when hydroxyethyl starch was used compared to albumin 5%. This effect was independent from a shedding of the endothelial glycocalyx. However, results presented here are from a subgroup analysis and must be considered with caution. Trial registration EudraCT number 2010-018343-34., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Rationale, Aims, and Objectives: During general anaesthesia, body core temperature is influenced by several factors that are either anaesthesia-related (type and duration of anaesthesia and fluid management), surgery-related (type of surgery and extent of the surgical procedure), or patient-related (age, gender, body weight, and preoperative body core temperature). Interestingly, data concerning body mass index (BMI) and its influence on patients' temperature are sparse. The aim of this study was to evaluate the impact of BMI on body core temperature under general anaesthesia., Methods: A single centre, prospective, observational study was conducted at a university hospital. Two cohorts (lower limb surgery and abdominal surgery) were evaluated. Patients were treated according to actual German guidelines for the prevention of hypothermia. Temperature was measured sublingually prior to anaesthesia and during the first 60 minutes of anaesthesia. Each cohort was divided in three subgroups (BMI < 24 kg m -2 , BMI 25-34.9 kg m -2 , and BMI > 35 kg m -2 ) according to body weight., Results: A total of 206 patients were evaluated. One hundred four underwent lower limb surgery; 102 underwent abdominal surgery. After induction of anaesthesia, temperature dropped in all subgroups, but this decline was more pronounced in patients with lower BMI. Significant differences concerning temperature changes were observed in abdominal surgery between low and high BMI groups. After 60 minutes of anaesthesia, group-dependent temperature differences had levelled out, and relevant differences compared with preoperative temperatures could no longer be observed in any of the groups., Conclusion: Current guidelines provide effective protection against perioperative hypothermia. In the current study, this was true for obese as well as normal weight patients., (© 2018 John Wiley & Sons, Ltd.)

Introduction: Postoperative nausea and vomiting (PONV) are complications of general anesthesia. Patient-specific factors, type of surgery and a variety of drugs determine the frequency. Clinical experience shows nausea and vomiting to be very frequent in morbidly obese patients undergoing bariatric surgery., Aim: To detect the onset and extent of nausea and vomiting in the group of morbidly obese patients undergoing laparoscopic bariatric surgery., Material and Methods: We conducted a retrospective data bank analysis (since 2004) of all patients with body mass index > 35 kg/m 2 undergoing laparoscopic bariatric surgery in comparison to patients with a body mass index < 35 kg/m 2 undergoing gastric surgery. Propensity score matching was applied to minimize bias effects. The frequency of postoperative nausea was defined as the primary outcome parameter., Results: One hundred and thirty-eight patients were included. There was a significant difference between the morbidly obese group and the control group concerning the frequency of postoperative nausea (15.9% vs. 55.1%; p < 0.001). In patients receiving volatile anesthetics a significant difference between groups concerning frequency of PONV was not observed. Intravenous anesthetics were suitable to reduce PONV in the control group but not in the morbidly obese group (12.5% vs. 56.8%, p < 0.001). With given prophylaxis PONV events still occurred in 15.6% vs. 48.8% (p = 0.003)., Conclusions: Morbidly obese patients undergoing laparoscopic bariatric surgery are at higher risk of suffering from PONV than non-morbidly obese patients. To reduce the PONV incidence in morbidly obese patients, further research, especially focusing on more efficient use of antiemetic drugs, seems to be necessary.

Background: The use of artificial colloids has declined in critical care, whereas they are still used in perioperative medicine. Little is known about the nephrotoxic potential in noncritically ill patients during routine surgery. The objective of this trial was to evaluate the influences of albumin 5% and balanced hydroxyethyl starch 6% (130/0.4) on renal function and kidney injury., Methods: One hundred urologic patients undergoing elective cystectomy were randomly assigned for this prospective, single-blinded, controlled study with two parallel groups to receive either albumin 5% or balanced hydroxyethyl starch 6% (130/0.4) as the only perioperative colloid. The primary endpoint was the ratio of serum cystatin C between the last visit at day 90 and the first preoperative visit. Secondary endpoints were estimated glomerular filtration rate and serum neutrophil gelatinase-associated lipocalin until the third postoperative day and risk, injury, failure, loss, and end-stage renal disease criteria at postoperative days 3 and 90., Results: The median cystatin C ratio was 1.11 (interquartile range, 1.01 to 1.23) in the albumin and 1.08 (interquartile range, 1.00 to 1.20) in the hydroxyethyl starch group (median difference = 0.03; 95% CI, -0.09 to 0.08; P = 0.165). Also, there were no significant differences concerning serum cystatin C concentrations; estimated glomerular filtration rate; risk, injury, failure, loss, and end-stage renal disease criteria; and neutrophil gelatinase-associated lipocalin. Infusion requirements, transfusion rates, and perioperative hemodynamics were similar in both groups., Conclusions: With respect to renal function and kidney injury, this study indicates that albumin 5% and balanced hydroxyethyl starch 6% have comparable safety profiles in noncritically ill patients undergoing major surgery.

Background: This study aims to investigate the effects of a modified, balanced crystalloid including phosphate in a perioperative setting in order to maintain a stable electrolyte and acid-base homeostasis in the patient., Methods/design: This is a single-centre, open-label, randomized controlled trial involving two parallel groups of female patients comparing a perioperative infusion regime with sodium glycerophosphate and Jonosteril® (treatment group) or Jonosteril® (comparator) alone. The primary endpoint is to maintain a stable concentration of weak acids [A - ] according to the Stewart approach of acid-base balance. Secondary endpoints are measurement of serum phosphate levels, other acid-base parameters such as the strong ion difference (SID), the onset and severity of postoperative nausea and vomiting (PONV), electrolyte levels and their excretion in the urine, monitoring of renal function and glycocalyx components, haemodynamics, amounts of catecholamines and other vasopressors used and the safety of the infusion regime., Discussion: Perioperative fluid replacement with the use of currently available crystalloid preparations still fail to maintain a stable acid-base balance and experts agree that common balanced solutions are still not ideal. This study aims to investigate the effectivity and safety of a new crystalloid solution by adding sodium glycerophosphate to a standardized crystalloid preparation in order to maintain a balanced perioperative acid-base homeostasis., Trial Registration: EudraCT number 201002422520 . Registered on 30 November 2010.

Introduction: Isotonic crystalloids play a central role in perioperative fluid management. Isooncotic preparations of colloids (for example, human albumin or hydroxyethyl starch) remain nearly completely intravascular when infused to compensate for acute blood losses. Recent data were interpreted to indicate a comparable intravascular volume effect for crystalloids, challenging the occasionally suggested advantage of using colloids to treat hypovolemia. General physiological knowledge and clinical experience, however, suggest otherwise., Methods: In a prospective study, double-tracer blood volume measurements were performed before and after intended normovolemic hemodilution in ten female adults, simultaneously substituting the three-fold amount of withdrawn blood with Ringer's lactate. Any originated deficits were substituted with half the volume of 20% human albumin, followed by a further assessment of blood volume. To assess significance between the measurements, repeated measures analysis of variance (ANOVA) according to Fisher were performed. If significant results were shown, paired t tests (according to Student) for the singular measurements were taken. P < 0.05 was considered to be significant., Results: A total of 1,097 ± 285 ml of whole blood were withdrawn (641 ± 155 ml/m(2) body surface area) and simultaneously replaced by 3,430 ± 806 ml of Ringer's lactate. All patients showed a significant decrease in blood volume after hemodilution (-459 ± 185 ml; P < 0.05) that did not involve relevant hemodynamical changes, and a significant increase in interstitial water content (+2,157 ± 606 ml; P < 0.05). The volume effect of Ringer's lactate was 17 ± 10%. The infusion of 245 ± 64 ml of 20% human albumin in this situation restored blood volume back to baseline values, the volume effect being 184 ± 63%., Conclusions: Substitution of isolated intravascular deficits in cardiopulmonary healthy adults with the three-fold amount of Ringer's lactate impedes maintenance of intravascular normovolemia. The main side effect was an impressive interstitial fluid accumulation, which was partly restored by the intravenous infusion of 20% human albumin. We recommend to substitute the five-fold amount of crystalloids or to use an isooncotic preparation in the face of acute bleeding in patients where edema prevention might be advantageous.

Background: With broad acceptance of Stewart's acid-base model "hyperchloremic acidosis" is regarded as an independent form of metabolic disorder. It is unknown whether hypernatremia plays a corresponding role with respect to the development of alkalosis., Methods: A total of 201 artificially ventilated, critically ill patients were monitored for hypernatremic episodes. Inclusion criterion was a serum sodium concentration above 145 mmol/l., Results: In 20 patients a total of 78 periods of elevated plasma sodium levels lasting at least 24 h were observed. In 86% of these cases sodium and chloride concentrations were simultaneously increased. The development of alkalosis correlated with the strong ion difference (r=0.80, p<0.01) but not with the serum sodium concentration (r=-0.031, p=0.78). In cases without accompanying hyperchloremia (13%) metabolic alkalosis regularly occurred and a correlation between serum sodium concentration and base excess could be verified (r=0.66, p=0.03). Alkalosis occurred in 84.8% of cases where the strong on difference exceeded 39 mmol/l., Conclusion: From the available data hypernatremic alkalosis could not be defined as an independent metabolic disorder. In would seem more appropriate to use the term "strong ion alkalosis" in this context.

Regional anaesthesia has gained increasing importance during the last decades. Successful regional anaesthesia for shoulder surgery requires a detailed knowledge of the relevant anatomy. Interscalene nerve blocks are most frequently used to anaesthetize the shoulder and among them the techniques according to Winnie, Meier, Pippa and Borgeat are the most popular. The techniques described by Meier and Borgeat are characterized by low complication rates. They are efficient for the majority of surgical procedures and therefore offer an interesting supplementation or an alternative to general anaesthesia. When carried out as a catheter-technique they provide a high quality postoperative pain therapy.