Coasting: worth the effort?

A new anesthesia machine incorporates a "coasting mode", but the extent to which a coasting technique can maintain anesthesia at the end of a procedure under optimal conditions (closed circuit anesthesia) remains unknown. Sixty-nine patients undergoing peripheral or abdominal surgery were assigned to 1 of 9 groups, depending on when desflurane coasting (in O2/air) was started (after 4, 9, 16, 25, 36, 49, 64, 81, or 100 min). The end-expired desflurane concentration was maintained at 4.5% in O2/air prior to coasting with a conventional anesthesia machine. After initiating coasting (using a closed-circuit technique), we examined when the end-expired desflurane concentration reached 70, 60, 50, and 40% of its value during maintenance (= 30, 40, 50 and 60% decrement times, respectively). Decrement times increased with increasing duration of anesthesia, and varied widely. After 64 min of maintenance anesthesia, the end-expired desflurane concentration remained at or above 70, 60, 50, and 40% of its maintenance value during 10.3 +/- 2.3, 16.0 +/- 3.5, 25.0 +/- 5.9, and 45.4 +/- 19.3 min, respectively (average +/- standard deviation). Coasting can briefly maintain anesthesia towards the end of a procedure. While savings with an automated coasting mode are likely to be modest per patient, they may become substantial when multiplied by the number of procedures per day per operating room with no increase in the clinical workload of the anesthesia provider.

Evidence of thromboembolism prophylaxis in bariatric surgery-results of a quality assurance trial in bariatric surgery in Germany from 2005 to 2007 and review of the literature.

BACKGROUND: Since January 1st, 2005, the current situation for bariatric surgery has been examined by means of a voluntary quality assurance study in Germany with a multicenter design in which 38 hospitals and surgical departments participated. The data are registered in cooperation with the Institute of Quality Assurance in Surgery at the Otto-von-Guericke University of Magdeburg (Germany). METHODS: Data describing peri-interventional characteristics were prospectively documented in an internet online data registry. All primary bariatric procedures performed since January 1st, 2005, were registered. In addition, reoperations in patients who had previously undergone primary surgical intervention were included. As a representative excerpt from the overall prospective multicenter observational study on obesity surgery, data on the type, regimen, and time course of deep venous thrombosis (DVT) prophylaxis were documented. From the number and spectrum of complications, the incidences of clinically manifest DVT or pulmonary embolism (PE) were derived during the in-hospital course and follow-up in conjunction with the type of surgical procedure and body mass index (BMI). RESULTS: Overall, 3,122 bariatric procedures were performed at 38 German hospitals between January 2005 and December 2007. These procedures were subdivided into 2,869 primary operations and 253 revisions (sex ratio, male to female = 25.6:74.4%). The average BMI of all patients was 48.5 kg/m(2) in 2005, 48.4 kg/m(2) in 2006, and 48.0 kg/m(2) in 2007. In 2005 and 2006, gastric banding (GB) was the most commonly performed operation, followed by Roux-en-Y gastric bypass (RYGBP). In 2007, RYGBP was carried out in 42.1% of all bariatric procedures. Interestingly, the incidence of deep venous thrombosis (DVT) was only 0.06%, whereas PE occurred in 0.06% of patients only after hospital discharge. The DVT prophylaxis protocol used has been changed for the last 2 years: the majority of patients with a BMI above 50 kg/m(2) received low-molecular-weight heparin twice a day. CONCLUSION: In Germany, a trend from GB to sleeve gastrectomy (SG) and malabsorptive approach has been evaluated. This trend is associated with differences of the DVT prophylaxis regimen in the profile of bariatric surgical patients depending on BMI and the type of bariatric procedure. Despite the low incidence of DVT and pulmonary embolism (PE) detected, there is a lack of evidence on a reasonable regimen for sufficient DVT prophylaxis in bariatric surgery; instead, there are only recommendations from the guidelines and statements of a specific medical society. Therefore, prospective studies are necessary to determine the optimal DVT prophylaxis for bariatric surgical patients as well as obese patients undergoing surgery.

Desflurane consumption with the Zeus during automated closed circuit versus low flow anesthesia.

INTRODUCTION: During automated closed-circuit anesthesia (CCA), the Zeus (Dräger, Lübeck, Germany) uses a high initial fresh gas flow (FGF) to rapidly attain the desired agent and carrier gas concentrations, resulting in a desflurane consumption well above patient uptake. Because both FGF and carrier gas composition can affect consumption, we determined the Zeus' agent consumption with automated CCA and with automated low flow anesthesia (LFA) (= maintenance FGF of 0.7 L min(-1)) with 3 different carrier gases. METHODS: After IRB approval, 65 ASA PS I or II patients undergoing general surgery received desflurane in either O2, O2/air, or O2/N2O, with the Zeus to maintain the end-expired concentration (FA) at 6, 6, and 4% and the F1O2 at 1.0, 0.6, and 0.4, respectively. In addition, patients were assigned to either automated CCA (O2 n = 11; O2/air n = 11; O2/N2O n = 11) or automated LFA (selected FGF 0.7 L min(-1)) (O2 n = 12; O2/air n = 11; O2/N2O n = 9). Demographics and desflurane consumption at 2, 4, 6, 8, 10, 20, 30, 40 and 50 min were compared. RESULTS: With the same carrier gas, desflurane consumption was lower with the CCA mode than with LFA mode after 4 min in the O2 groups, 6 min in the O2/air groups, and 30 min in the O2/N2O groups. Within each mode, desflurane consumption in the O2 and O2/air groups was identical at all times. Despite the use of a lower FA in the N2O groups, initial desflurane consumption was higher than in the O2 and O2/air groups, but it was lower later (> or = 15 min) only with LFA. DISCUSSION: After 50 min, desflurane consumption with automated CCA is lower than with automated LFA. However, initial agent consumption is complex, and N2O in particular may increase initial desflurane consumption (though ultimately resulting in lower desflurane usage because of its MAC sparing effect) because initial FGF is increased to rapidly reach the target concentrations. Differences in desflurane consumption only become apparent after FGF has stabilized to the target FGF.

Results of sleeve gastrectomy-data from a nationwide survey on bariatric surgery in Germany.

BACKGROUND: Beginning January 1, 2005, the status and outcomes of bariatric surgery were examined in Germany. Data are registered in cooperation with the An-Institute of quality assurance in surgery at the Otto-von-Guericke-University Magdeburg. The objective of this study was to examine the morbidity and mortality rates secondary to sleeve gastrectomy (SG) in Germany since 2006. METHODS: Data collection occurred prospectively in an online data bank. All primary bariatric procedures performed were recorded as were all re-operations in patients that had already undergone a primary operation. Specific data compiled on the sleeve gastrectomy procedure were evaluated with a focus on operative details and complication rates. RESULTS: The total study cohort contains 3,122 patients. From January 2006 to December 2007, 144 sleeve gastrectomy procedures were performed in the 17 hospitals participating in the study. The mean body mass index (BMI) of all patients was 48.8 kg/m(2). The BMI of patients undergoing SG was 54.5 kg/m(2). In total, 73.8% of the patients were female and 26.2% of the patients were male. There were no significant differences between patients undergoing SG. The general complication rate after SG was 14.1%, and the surgical complication rate was 9.4%. The postoperative mortality rate was 1.4%. CONCLUSIONS: The complication rate during the first 2 years after SG in Germany is similar to that published in the literature. In order to improve the quality of bariatric surgery, an evaluation of data from a German multicenter trial is necessary to evaluate the position of SG in the bariatric algorithm.

A nationwide survey on bariatric surgery in Germany--results 2005-2007.

BACKGROUND: Most studies on bariatric surgery outcomes are performed as clinical trials or reflect the clinical experience in single centers. The status of bariatric surgery in Germany has been examined since January 1st, 2005 with the cooperation of clinics and hospitals at the Institute of Quality Assurance in Surgery at the Otto-von-Guericke University of Magdeburg (Germany). METHODS: In this prospective multicenter observational study, the data obtained for all primary bariatric procedures, including all repeated operations, performed on consecutive patients with morbid obesity at participating hospitals from 2005 to 2007 were prospectively collected using an Internet online data registry. In particular, perioperative characteristics, such as the spectrum of diagnostic measurements, type of surgical procedures, and short- and long-term outcomes, were investigated. RESULTS: During the study period, 629 surgical procedures were performed at 21 hospitals in 2005, 828 procedures at 32 hospitals in 2006, and 1,666 procedures at 35 hospitals in 2007. In 2005 and 2006, gastric banding was the most frequently performed operation, followed by the Roux-en-Y gastric bypass (RYGBP). In 2007, a RYGBP was carried out in 42.1% of all bariatric procedures. Among all patients, 74.4% were female. The mean body mass index (BMI) was 48.5 kg/m(2) in 2005, 48.4 kg/m(2) in 2006, and 48.0 kg/m(2) in 2007. Follow-up data after 12 months were available for 63.8% of the patients in 2005 and 2006; these data showed greater reduction of BMI after malabsorptive rather than restrictive bariatric procedures. The mortality was 0.1% (30 days) and 0.16% (overall). CONCLUSION: As indicated by the worldwide trend, there is an ongoing change from restrictive bariatric procedures to malabsorptive procedures and sleeve gastrectomy. Although the BMIs of German patients undergoing bariatric surgery appear to be substantially higher than those of patients from most other countries, there were no differences in intraoperative and short-term complications or in overall outcomes during follow-up when compared with published studies.

Pulmonary gas exchange is well preserved during robot assisted surgery in steep Trendelenburg position.

INTRODUCTION: During robot assisted hysterectomies and prostatectomies, surgical exposure demands the application of a CO2 pneumoperitoneum with a very steep Trendelenburg position (40 degrees). The extent to which oxygenation and ventilation might be compromised intra-operatively remains poorly documented. METHODS: Dead-space ventilation and venous admixture were determined in 18 patients undergoing robot assisted hysterectomy (n = 6) or prostatectomy (n = 12). Anesthesia was maintained with desflurane in O2 or O2/air, with the inspired O2 fraction left at the discretion of the attending anesthesiologist. Controlled mechanical ventilation was used, but 15 min after assuming the Trendelenburg position and up until resuming the supine position pressure controlled ventilation was used. Dead-space ventilation and venous admixture were determined using Bohr's formula and Nunn's iso-shunt diagram, respectively, at the following 7 stages of the procedure: 15 min after induction; 5 min after applying the CO2 pneumoperitoneum (intra-abdominal pressure 12 mm Hg) but while still supine; 5, 60, and 120 min after assuming the Trendelenburg positioning; and 5 and 15 min after reassuming the supine position. RESULTS: Venous admixture did not change. Dead-space ventilation increased after Trendelenburg positioning, and returned to baseline values after resuming the supine position. However, individual patterns varied widely. DISCUSSION: The lung has a remarkable yet incompletely understood capacity to withstand the effects of a CO2 pneumoperitoneum and steep Trendelenburg position during general anesthesia. While individual responses vary and should be monitored, effects on dead-space ventilation and venous admixture are small and should not be an obstacle to provide optimal surgical exposure during robot assisted prostatectomy or hysterectomy.

[Quality assurance in bariatric surgery in Germany--results of the German multicentre trial 2005 and 2006]. / Studie zur Qualitätskontrolle der operativen Therapie der Adipositas--Ergebnisse der Jahre 2005 und 2006.

BACKGROUND: Since January 1st 2005, the situation of bariatric surgery in Germany has been examined. The data are registered in cooperation with the Institute of Quality Assurance in Surgery at the Otto-von-Guericke-University Magdeburg. METHODS: The data registration took place prospectively in an internet online data base. All primary bariatric procedures performed since January 1st 2005 were detected as well as re-operations in patients who had been operated before. RESULTS: 629 patients underwent bariatric surgery in 21 hospitals in 2005 and 828 patients were operated in 32 hospitals in 2006. The mostly performed operation was gastric banding with 46.8 %, followed by Roux-Y gastric bypass with 38.5 %. 74.4 % of the patients were female. The medium BMI of all patients was 48.5 kg/m2 in 2005 and 48.4 kg/m2 in 2006. Follow-up data were available for 71.2 % of the patients operated in 2005. These data show a higher reduction of BMI after malabsorptive than after restrictive bariatric procedures. CONCLUSION: A trend from restrictive bariatric procedures to a malabsorptive approach could be observed. In Germany the BMI of patients undergoing bariatric surgery is higher than in most countries world-wide. No differences could be detected in intraoperative and short-term complications as well in the complication rate in the first year of follow-up in comparison with the literature.

PROCEED: Prospective Obesity Cohort of Economic Evaluation and Determinants: baseline health and healthcare utilization of the US sample.

AIM: To summarize baseline characteristics, health conditions, resource utilization and resource cost for the US population for the 90-day period preceding enrolment, stratified by body mass index (BMI) and the presence of abdominal obesity (AO). METHODS: PROCEED (Prospective Obesity Cohort of Economic Evaluation and Determinants) is a multinational, prospective cohort of control (BMI 20-24.0 kg/m(2)), overweight (BMI 25-29.9 kg/m(2)) and obese (BMI >or= 30 kg/m(2)) subjects with AO and without AO [non-abdominal obesity (NAO)], defined by waist circumference (WC) >102 and 88 cm for males and females, respectively. Subjects were recruited from an Internet consumer panel. Outcomes were self-reported online. Self-reported anthropometric data were validated. Prevalence of conditions and utilization is presented by BMI class and AO within BMI class. Differences in prevalence and means were evaluated. RESULTS: A total of 1067 overweight [n = 474 (NAO: n = 254 and AO: n = 220)] and obese [n = 493 (NAO: n = 39 and AO: n = 454)] subjects and 100 controls were recruited. Self-reported weight (r = 0.92) and WC (r = 0.87) were correlated with measured assessments. Prevalence of symptoms was significantly higher in groups with higher BMI, as were hypertension (p < 0.0001), diabetes (p < 0.0001) and sleep apnoea (p < 0.0001). Metabolic risk factors increased with the BMI class. Among the overweight class, subjects with AO had significantly more reported respiratory, heart, nervous, skin and reproductive system symptoms. Overweight subjects with AO reported a significantly higher prevalence of diabetes (13%) compared with overweight subjects with NAO (7%, p = 0.04). Mean healthcare cost was significantly higher in the higher BMI classes [control ($456 +/- 937) vs. overweight ($1084 +/- 3531) and obese ($1186 +/- 2808) (p < 0.0001)]. CONCLUSION: An increasing gradient of symptoms, medical conditions, metabolic risk factors and healthcare utilization among those with a greater degree of obesity was observed. The independent effect of AO on health and healthcare utilization deserves further study with a larger sample size.

Experiences of two centers of bariatric surgery in the treatment of intragastrale band migration after gastric banding-the importance of the German multicenter observational study for quality assurance in obesity surgery 2005 and 2006.

BACKGROUND: Adjustable silicone gastric banding (ASGB) is an effective treatment in morbid obesity. Band migration is a long-term complication. Causes, clinical symptoms, timing and incidence are investigated in single centres only. In Germany, since January 1st, 2005, practice in bariatric surgery has been investigated in German prospective multicenter trial for quality assurance in obesity surgery. MATERIALS AND METHODS: All patients underwent ASGB in two centres of bariatric surgery in Germany were prospectively registered using a computer-based data form. Patients with band migration were retrospectively evaluated, in particular, causes and characteristics of its management. The results were correlated with data obtained from the German prospective multicentre trial. RESULTS: In total, 493 patients were enrolled in the study from February 1995 to February 2007. The follow-up rate was 79.9% (mean follow-up time period, 78.7 months; range, 2-148 months). Fifteen patients (3.0%) developed migration. In 14 cases, migration occurred within the range of 30-86 months after implantation. In one case, migration occurred 10 months after repositioning of the band. In the German multicentre trial, 629 patients underwent surgery during 2005 and 827 patients in 2006. In both periods, 74.4% of the patients were female and 25.6% male. The most frequently performed operation was ASGB (46.8%) followed by Roux-en-Y gastric bypass (38.5%). CONCLUSION: Band migration requires band removal. Different symptoms and complications influence the kind of band removal. Multicentre data were evident in the case of high long-term complication rate after ASGB. Data of the German multicentre trial show the trend from restrictive bariatric procedures to malabsorptive approach.

Intraoperative pulmonary embolism and intracardiac thrombosis complicating liver transplantation: a systematic review.

BACKGROUND: Pulmonary embolism (PE) and intracardiac thrombosis (ICT) are rare but potentially lethal complications during orthotopic liver transplantation (OLT). METHODS: We aimed to review clinical and pathological correlates of PE and ICT in patients undergoing OLT. A systematic review of the literature was conducted using MEDLINE and ISI Web of Science. RESULTS: Seventy-four cases of intraoperative PE and/or ICT were identified; PE alone in 32 patients (43%) and a combination of PE and ICT in 42 patients (57%). Most frequent clinical symptoms included systemic hypotension and concomitant rising pulmonary artery pressure, often leading to complete circulatory collapse. PE and ICT occurred in every stage of the operation and were reported equally in patients with or without the use of venovenous bypass or antifibrinolytics. A large variety of putative risk factors have been suggested in the literature, including the use of pulmonary artery catheters or certain blood products. Nineteen patients underwent urgent thrombectomy or thrombolysis. Overall mortality was 68% (50/74) and 41 patients (82%) died intraoperatively. CONCLUSION: Mortality was significantly higher in patients with an isolated PE, compared to patients with a combination of PE and ICT (91% and 50%, respectively; P < 0.001). Intraoperative PE and ICT during OLT appear to have multiple etiologies and may occur unexpectedly at any time during the procedure.

The kinase inhibitor imatinib--an immunosuppressive drug?

The phenylaminopyrimidine-derivate Imatinib mesylate has been developed for targeted inhibition of the Abelson kinase (c-ABL), which is constitutively activated when translocated to the genetic locus of the breakpoint cluster region (leading to the BCR/ABL fusion gene), thereby forming the causative pathogenetic event for the development of chronic myeloid leukemia (CML). Of note, due to its physico-chemical properties, kinase specificity of Imatinib is limited. Despite of its well documented clinical efficacy mediated by inhibition of constitutively activated tyrosine kinases such as BCR/ABL in CML, PDGF-RA in HES and mutated c-kit in GIST patients, other tyrosine kinases such as Flt-3, Lck and mitogen-activated kinases (MAPK) are affected as well. Accordingly, it has recently been shown that therapeutic doses of Imatinib also target a variety of immune cells, e.g. by modulating the differentiation of dendritic cells (DC) as well as by impeding proper T-cell and macrophage function. In contrast, combining Imatinib with Interleukin 2 (IL-2) potently activates NK-cells and led to the description of a new subclass of DC, so-called IK-DC. The latter mediate Imatinib/IL-2-induced regression of tumors in pre-clinical animal models via production of high amounts of IFN-gamma and the death receptor ligand TRAIL. Thus, Imatinib exerts potent immuno-modulatory effects in vitro and in vivo, which will be discussed together with their clinical relevance in detail throughout this review.

Large volume N2O uptake alone does not explain the second gas effect of N2O on sevoflurane during constant inspired ventilation.

BACKGROUND: The second gas effect (SGE) is considered to be significant only during periods of large volume N(2)O uptake (VN(2)O); however, the SGE of small VN(2)O has not been studied. We hypothesized that the SGE of N(2)O on sevoflurane would become less pronounced when sevoflurane administration is started 60 min after the start of N(2)O administration when VN(2)O has decreased to approximately 125 ml min(-1), and that the kinetics of sevoflurane under these circumstances would become indistinguishable from those when sevoflurane is administered in O(2). METHODS: Seventy-two physical status ASA I-II patients were randomly assigned to one of six groups (n=12 each). In the first four groups, sevoflurane (1.8% vaporizer setting) administration was started 0, 2, 5 and 60 min after starting 2 litre min(-1) O(2) and 4 litre min(-1) N(2)O, respectively. In the last two groups, sevoflurane (1.8 or 3.6% vaporizer setting) was administered in 6 litre min(-1) O(2). The ratios of the alveolar fraction of sevoflurane (Fa) over the inspired fraction (Fi), or Fa/Fi, were compared between the groups. RESULTS: Sevoflurane Fa/Fi was larger in the N(2)O groups than in the O(2) groups, and it was identical in all four N(2)O groups. CONCLUSIONS: We confirmed the existence of a SGE of N(2)O. Surprisingly, when using an Fa of 65% N(2)O, the magnitude of the SGE was the same with large or small VN(2)O. The classical model and the graphical representation of the SGE alone should not be used to explain the magnitude of the SGE. We speculate that changes in ventilation/perfusion inhomogeneity in the lungs during general anaesthesia result in a SGE at levels of VN(2)O previously considered by most to be too small to exert a SGE.

The RANKL/OPG system is activated in inflammatory bowel disease and relates to the state of bone loss.

BACKGROUND AND AIMS: A substantial proportion of patients with inflammatory bowel disease (IBD) develops osteopenia and osteoporosis in the course of disease. Recent data from a mouse model of colitis suggest that the receptor activator of nuclear factor kappa B (RANKL)/osteoprotegerin (OPG) system may be responsible for bone loss. METHODS: We investigated the activation state of the RANKL/OPG system and its association with bone loss in human IBD. Plasma levels of OPG and RANKL were correlated with bone mineral density and current IBD therapy. Colonic secretion of OPG and RANKL and cell types responsible for such secretion were determined. RESULTS: OPG plasma levels were elevated 2.4-fold in Crohn's disease (CD) and 1.9-fold in ulcerative colitis (UC) whereas soluble RANKL (sRANKL) levels were not significantly different in IBD patients compared with healthy controls. High levels of OPG were released from colonic explant cultures (CEC) derived from inflamed IBD specimens, and colonic macrophages and dendritic cells costained for OPG. sRANKL levels from CEC were low both in IBD patients and healthy controls. Interestingly, increased expression of RANKL was mainly confined to cells in the lamina muscularis. A significant negative correlation was found between OPG plasma levels and femoral neck/lumbar spine bone mineral density. CONCLUSIONS: We have demonstrated that IBD is associated with alterations in the RANKL/OPG system. Applying results from a murine model of colitis associated bone loss, the constellation of OPG and sRANKL regulation observed in our study raises the possibility that RANKL/OPG may contribute to the development of bone loss in IBD.

Do psychosocial variables predict weight loss or mental health after obesity surgery? A systematic review.

OBJECTIVE: The objective of this study was to present a systematic review of psychological and psychosocial predictors of weight loss and mental health after bariatric surgery. This systematic review included all controlled and noncontrolled trials of the last 2 decades with either a retrospective or prospective design and a follow-up period of at least 1 year. RESEARCH METHODS AND PROCEDURES: The relevant literature was identified by a search of computerized databases. All articles published in English and German between 1980 and 2002 were reviewed. RESULTS: Using the above inclusion/exclusion criteria, 29 articles were identified focusing on psychosocial predictors of weight loss and mental health after obesity surgery. DISCUSSION: Personality traits have no predictive value for the postoperative course of weight or mental state. Apart from serious psychiatric disorders including personality disorders, psychiatric comorbidity seems to be of more predictive value for mental and physical well-being as two essential aspects of quality of life than for weight loss postsurgery. However, depressive and anxiety symptoms as correlates of psychological stress with regard to obesity seem to be positive predictors of weight loss postsurgery. The severity of the symptoms or the disorder is more relevant for the outcome of obesity surgery than the specificity of the symptoms. It is also not solely the consumption of distinct "forbidden" foods, such as sweets or soft drinks, but rather a general hypercaloric eating behavior, either as an expression of the patient's inadequate compliance or a dysregulation in energy balance, which is associated with a poor weight loss postsurgery.