[Conversional and endoscopic procedures following bariatric surgery]. / Konversionseingriffe und endoskopische Revisionsverfahren nach erfolgter bariatrischer Chirurgie.

The Roux-en-Y gastric bypass (RYGB) is the therapy of choice in bariatric surgery. Sleeve gastrectomy and gastric banding are showing higher rates of treatment failure, reducing obesity-associated morbidity and body weight insufficiently. Moreover, gastroesophageal reflux disease (GERD) can occur refractory to medication. Therefore, a laparoscopic conversion to RYGB can be reasonable as long as specific conditions are fulfilled.Endoscopic procedures are currently being applied to revise bariatric procedures. Therapy failure following RYGB occurs in up to 20 % of cases. Transoral outlet reduction is the minimally invasive method of choice to reduce gastrojejunal anastomosis of the alimentary limb. The diameter of a gastric sleeve can be unwantedly enlarged as well; that can be reduced by placement of a longitudinal full-thickness suture.Severe hypoglycemic episodes can be present in patients following RYGB. Hypoglycemic episodes have to be diagnosed first and can be treated conventionally. Alternatively, a laparoscopic approach according to Branco-Zorron can be used for non-responders. Hypoglycemic episodes can thus be prevented and body weight reduction can be assured.Conversional and endoscopic procedures can be used in patients with treatment failure following bariatric surgery. Note that non-invasive approaches should have been applied intensively before a revisional procedure is performed.

Effects of animal positioning on catecholamine and vasopressin levels in pigs undergoing laparoscopy.

BACKGROUND: The aim of this study was to determine the influence of different therapeutic interventions and positions on catecholamine and vasopressin levels in the pneumoperitoneum (PN) in a porcine model. METHODS: In 43 pigs, a 14-mm-Hg PN was established and plasma concentrations of epinephrine, norepinephrine and vasopressin were measured in head-up, supine and head-down positions. Additionally, the effects of the following changes were studied: (1) increase in intrathoracic blood volume (ITBV) by means of hydroxyethyl starch infusion; (2) vasodilatation induced by sodium nitroprusside, or (3) selective sympathicolysis induced by esmolol. Again, catecholamines (ELISA) and vasopressin (RIA) were determined. RESULTS: After PN, epinephrine levels did not significantly increase in the head-up position (p = 0.075) and remained also unchanged in the supine or head-down position. Plasma norepinephrine statistically significantly decreased in the head-up position (p = 0.046). Vasopressin concentrations remained unaltered. After increased ITBV, neither catecholamine nor vasopressin concentrations changed in any body position. Application of sodium nitroprusside or esmolol caused no changes. CONCLUSION: Changes in endogenous catecholamine levels safely prevent cardiocirculatory instability in small pigs. Volume substitution might reduce endocrine responses to PN in the head-up position.

"Fast-track" rehabilitation for elective colonic surgery in Germany--prospective observational data from a multi-centre quality assurance programme.

BACKGROUND: The results of "Fast-track" colonic surgery in an unselected population outside of specialised units has been unknown yet. MATERIALS AND METHODS: Data from 24 German hospitals performing "Fast-track" rehabilitation as the standard peri-operative care for patients undergoing elective colonic resection were collected in a prospective multi-centre study conducted between April 2005 and September 2006 to evaluate local and general morbidity. RESULTS: One thousand and forty-seven patients undergoing elective "fast-track" colonic resection were included. Compliance to essential parts of "fast-track" rehabilitation was high (epidural analgesia 86,6%, early oral feeding and mobilisation on the day of surgery 85.5 and 85.4%). Surgical morbidity was observed in 148 patients (14.1%) and general morbidity in 95 patients (9.1%), while mortality was 0.8%. Predefined discharge criteria were met within 5 (1-83) days after surgery, but because of economical restraints in the German DRG system, patients were discharged only after 8 (3-83) days. Re-admission rate was 3.9%. CONCLUSION: "Fast-track" rehabilitation for elective colonic resection was safe and feasible in German hospitals of all sizes and yielded a low general morbidity and re-admission rate. Post-operative recovery was enhanced, but discharge from hospital was delayed because of economical reasons.

"Fast-track" rehabilitation after colonic surgery in elderly patients--is it feasible?

BACKGROUND AND AIMS: The aim of the "fast-track" rehabilitation after elective colonic surgery is to lower the extent of general complications. Elderly patients may especially profit from this multi-modal peri-operative treatment including enforced early mobilisation and oral nutrition. MATERIALS AND METHODS: In this prospective study using a well-defined post-operative multi-modal treatment programme, we examined the feasibility of this so-called fast-track rehabilitation in elderly patients. The programme employed combined thoracic peri-dural analgesia, early enforced mobilisation and rapid oral nutrition. RESULTS: Seventy-four consecutive patients older than 70 years with benign or malignant disease of the large intestine were operated on. All patients were treated peri-operatively using the "fast-track" rehabilitation programme. Of the patients, 84% were able to have liquids orally on the day of surgery and 86% had solid food on the 1st post-operative day. The median time until the first bowel movement was 2 days. Only 12 (16%) patients had a total of 16 local complications, including 2 (3%) patients with anastomotic leakages. Nine patients (12%) had a total of 14 general complications; mortality rate was 1% (n=1). Patients were discharged from the hospital 5 (5th-95th percentile=4-6 days) days after surgery. CONCLUSION: Using the "fast-track" rehabilitation programme on elderly patient is not only feasible but may also lower the number of general complications and the duration of the hospital stay.

[Value of laparoscopic surgery in elective colorectal surgery with "fast-track"-rehabilitation]. / Stellenwert der laparoskopischen Chirurgie im Rahmen der "Fast-track"-Rehabilitation nach elektiven kolorektalen Resektionen.

INTRODUCTION: Laparoscopic (LAP) versus open (CON) colonic resection with traditional perioperative care has some short term benefits postoperatively regarding functional recovery. Whether these benefits may also occur when all patients are treated with multimodal "fast-track"-rehabilitation programs is questionable. METHODS: Patients undergoing elective left sided colonic surgery were prospectively non randomised observed. The "fast-track" program included patient information, thoracic peridural analgesia, forced mobilisation and oral intake, and stress reduction. Endpoints were duration of postoperative ileus and hospital stay, general- and local complication, and pulmonary function. RESULTS: 147 consecutive patients were operated on, 47 open and 100 laparoscopically. The time until oral intake was completed seemed to be shorter in the LAP-group (p=0.07) followed by a shorter hospital stay (p<0.01). The pulmonary function was postoperatively improved in the LAP-group compared to the CON-group (p<0,01). General complications (LAP 9% vs. CON 17%) were non significantly increased in the CON-group. Local complications increased in the CON-group (LAP 13% vs. CON 28%, p<0,05). CONCLUSION: Even with perioperative "fast-track"-rehabilitation programs short term advantages were found in laparoscopic compared with open colonic surgery in a non randomised population. The clinical relevance should be examined in controlled randomised trials.

A compilation of two decades of mutagenicity test results with the Ames Salmonella typhimurium and L5178Y mouse lymphoma cell mutation assays.

As previously reported [Cameron, T. P., Rogers-Back, A. M., Lawlor, T. E., Harbell, J. W., Seifried, H. E., and Dunkel, V. C. (1991) Gentoxicity of multifunctional acrylates in the Salmonella/mammalian-microsome assay and mouse lymphoma TK+/- assay. Environ. Mol. Mutagen. 17, 264-271], the National Cancer Institute (NCI) shares the responsibility of selecting the most significant chemicals for carcinogenicity testing by the National Toxicology Program (NTP) and has used data from Salmonella and mouse lymphoma mutagenicity assays to aid in the selection and prioritization of chemicals to be further evaluated in chronic 2 year rodent studies. In addition, a number of antineoplastic and anti-AIDS drugs in preclinical evaluation were tested for the NCI's Division of Cancer Treatment Toxicology Branch. In the NCI/NTP chemical selection process, it is no longer necessary to test chemicals prior to sending them to the NTP so the NCI program has ceased performing mutagenicity tests. Some of the testing data has been made available in summary form in the Chemical Carcinogenisis Research Information System (CCRIS), which is searchable on the NLM TOXNET system. The limitations in using this source are that only summary results are available and many negative test results are not included. A summary table that presents the results for each compound is provided in the Appendix with raw data provided in the Supporting Information. The Appendix table contains the compound name, CAS number, and a summary of the data from the Ames test and the mouse lymphoma assay.

Systematic evaluation of different approaches for minimizing hemodynamic changes during pneumoperitoneum.

BACKGROUND: Capnoperitoneum (CP) compromises hemodynamic function during laparoscopy. Three therapeutic concepts were evaluated with an aim to minimize the hemodynamic reaction to CP: First, a controlled increase of intrathoracic blood volume (ITBV) by intravenous fluids; second, partially reduced sympathetic activity by the beta1-blocker esmolol; and third, a decrease in mean arterial pressure (MAP) by the vasodilator sodium nitroprusside. METHODS: For this study, 43 pigs were assigned to treatment with fluid and sodium nitroprusside (group A) or with esmolol (group B). In both groups, the pigs were assigned to head-up, head-down, or supine position, resulting in three different subgroups. Invasive hemodynamic monitoring was established including left heart catheter and cardiac oxygen lung water determination (COLD) measurements. Measurements were documented before CP with the animals in supine position, after induction of a 14-mmHg CP with the animals in each body position, after a 10% reduction in MAP by vasodilation, and after an increase in ITBV of about 30% by infusion of 6% hydroxyethylstarch solution. RESULTS: Increasing ITBV improved hemodynamic function in all body positions during CP. Esmolol reduced cardiac output and myocardial contractility. Sodium nitroprusside did not improve hemodynamic function in any body position. CONCLUSIONS: Optimizing volume load is effective for minimizing hemodynamic changes during CP in the head-up and in head-down positions. In general, beta(1)-blockers cannot be recommended because they might additionally compromise myocardial contractility and suppress compensatory reaction of the sympathetic nerve system. Vasodilation has not improved hemodynamic parameters during CP.

Fibrinolytic capacity in peritoneal fluid after laparoscopic and conventional colorectal resection: data from a randomized controlled trial.

BACKGROUND: A reduced peritoneal fibrinolytic capacity after surgery is currently accepted to be the main cause for postoperative adhesions. The aim of this prospective randomized trial was to determine the fibrinolytic activity in peritoneal fluid after laparoscopic as compared to conventional colorectal resection. METHODS: A randomized controlled trial in parallel with the multicenter trial Lapkon II was conducted. Peritoneal fluid was sampled via drain at 2, 8, and 24 h after elective laparoscopic (n=14; LAP) and conventional (n=16; CON) colorectal resections. Activities and concentrations of tissue plasminogen activator (t-PA), plasminogen activator inhibitor type-1 (PAI-1) and t-PA/PAI complex were determined in all specimen by ELISA kits. RESULTS: There was no difference in age, sex or body mass index between both groups. Postoperatively, t-PA activity decreased in both groups and was lower 2 h after closing the abdomen in the laparoscopic group (p<0.05). PAI-1 activity and concentration increased in both groups. Difference between the groups was measured for PAI-1 concentration after 24 h (p<0.05). There were no differences between the groups regarding t-PA concentrations, PAI-1 activity and t-PA/PAI complex. CONCLUSIONS: After closing the abdominal cavity, postoperative changes in fibrinolytic capacity of peritoneal fluid can be determined in samples collected by a drain. However, there were no major differences in the postoperative course of fibrinolytic capacity in peritoneal fluid after laparoscopic and conventional colorectal resections.

[Problem-based learning for surgery. Increased motivation with less teaching personnel?]. / Problemorientiertes Lernen in der Chirurgie. Erhöhte Lernmotivation bei geringerem Personalaufwand?

BACKGROUND: Traditional teacher-centred education strategies often do not meet the needs and student abilities of adult learning. The introduction of small learning groups requires considerable increases in staff. Problem-based learning could increase the motivation to acquire knowledge but without being as staff-intensive. METHODS: Medical students (n=98) in their fourth clinical semester were randomly assigned to either a structured course (SC) or problem-based learning (PBL) for surgery. Their motivation and acceptance of the courses were recorded at the end of term in anonymous questionnaires using Likert scales, with scores ranging from 1 (very good) to 6 (unsatisfactory). RESULTS: Both course structure and the teachers received much better ratings from the PBL students (P<0.01 each). The motivation of students to deal with surgical problems beyond the course material was significantly higher after PBL, with 1.8 (0.7), than after the structured course with 3.1 (1.2) (P<0.01). The overall rating was substantially worse for the structured course, with 3.1 (1.2) than for PBL at 1.4 (0.6) (P<0.01). CONCLUSIONS: Problem-based learning in the surgical curriculum increases student acceptance and motivation with little demand on staff. It should be increasingly implemented.

["Fast-track" colonic surgery-first experience with a clinical procedure for accelerating postoperative recovery]. / "Fast-track-Kolonchirurgie"Erste Erfahrungen mit einem "clinical pathway" zur Beschleunigung der postoperativen Rekonvaleszenz.

OBJECT: The aim of multimodal perioperative treatment concepts is to lower the extent of general complications after elective colonic resection and "traditional" perioperative therapy and to allow hospital discharge only a few days following the operation. MATERIALS AND METHODS: In this prospective study, we examined a new perioperative treatment plan for accelerating postoperative recovery and evaluated the results. This so-called "fast-track" program employs combined thoracal peridural analgesia, forced mobilization, and rapid renourishment within the clinic. RESULTS: Sixty-four consecutive patients with benign or malignant disease of the large intestine aged an average of 66 years (range 54-71) were operated on. Thirty received conventional resection and 34 were operated on laparoscopically and treated perioperatively using the fast-track program. The hospital diet was given in all cases on the 1st postoperative day, and the first bowel movement occurred on the 2nd day (range 2-3). The patients could be released on the 4th postresection day (range 4-5). General and local postoperative complications were observed in five patients each (8%), including two cases of anastomotic insufficiency. CONCLUSION: In colonic surgery, the "fast-track" method accelerated convalescence, lowered the number of general complications, and reduced the duration of hospital stay. Therefore, evaluation of "fast-track" concepts is warranted in other types of elective abdominal surgery.

'Fast-track' multimodal rehabilitation program improves outcome after laparoscopic sigmoidectomy: a controlled prospective evaluation.

BACKGROUND: Laparoscopic colorectal resection improves patient outcome by reducing pain, postoperative pulmonary dysfunction, gastrointestinal paralysis, and fatigue. A multimodal rehabilitation program ("fast-track") with epidural analgesia, early oral feeding, and enforced mobilization may further improve the excellent results of laparoscopic colorectal resection, enabling early ambulation of these patients. METHODS: Fifty two consecutive patients underwent laparoscopic sigmoidectomy with standardized regular perioperative treatment (standard) or multimodal rehabilitation program ("fast-track"). Outcome measures included pulmonary function, duration of postoperative ileus, pain perception, fatigue, morbidity, and mortality. RESULTS: Twenty nine standard-care patients (19 men and 10 women) and 23 fast-track patients (15 men and eight women) were evaluated. Demographic and operative data were similar for the two groups. On the 1st postoperative day, pulmonary function was improved (p = 0.01) in fast-track patients. Oral feeding was achieved earlier (p < 0.01) and defecation occurred earlier (p < 0.01) in the fast-track group. Visual analogue scale scores for pain were similar for the two groups (p > 0.05), but fatigue was increased in the standard-care group on the 1st (p = 0.06) and 2nd (p < 0.05) postoperative days. Morbidity was not different for the two groups. Fast-track patients were discharged on day 4 (range, 3-6) and standard-care patients on day 7 (range, 4-14) (p < 0.001). CONCLUSION: Multimodal rehabilitation can improve further on the excellent results of laparoscopic sigmoidectomy and decrease the postoperative hospital stay.

Prospective randomized trial to determine the influence of laparoscopic and conventional colorectal resection on intravasal fibrinolytic capacity.

BACKGROUND: Although the pneumoperitoneum decreases venous reflux from the lower extremities, the rate of thromboembolic complcations seems to be lower after laparoscopic than after conventional procedures. Therefore, it has been assumed that laparoscopic surgery better preserves the intravasal fibrinolytic capacity. The aim of this study was to determine the influence of the operative technique on intravasal fibrinolytic capacity in colorectal resection. METHODS: Randomized controlled trial conducted in parallel with the multicenter trial LAPKON II comparing the long-term effects of elective laparoscopic (group I) and conventional (group II) resections for colorectal cancer. Blood samples were taken from 30 patients preoperatively, at the beginning and end of surgery as well as 2, 8, and 24 hr postoperatively. Activities and concentrations of tissue plasminogen activator (tPA), plasminogen activator inhibitor type 1 (PAI-1), tPA/PAI complex, fibrinogen, and D-dimers were determined in all specimen with ELISA tests. Area under the curve values (AUC) were calculated for all parameters. RESULTS: Patient characteristics and indication for surgery were not different between both groups. Preoperative values of fibrinolytic parameters were similar in both groups. Postoperatively, tPA activity decreased significantly in both groups, but AUC values for tPA and PAI-1 activity (p = 0.23; p = 0.68); concentration of tPA, PAI-1, and tPA/PAI complex (p = 0.52; p = 0.78; p = 0.95); and concentration of fibrinogen and D-dimers (p = 0.67; p = 0.71) did not differ between the groups. CONCLUSIONS: An intravasal fibrinolytic "shutdown" occurs not only after conventional but also after laparoscopic colorectal resection. Both operative techniques had similar effects on postoperative intravasal fibrinolytic capacity. Therefore, the lower incidence of thromboembolic complications after laparoscopic colorectal resections does not seem to be caused by a lesser depression of the intravasal fibrinolytic capacity.

Effect of laparoscopic and conventional colorectal resection on peritoneal fibrinolytic capacity: a prospective randomized clinical trial.

BACKGROUND AND AIMS: Reduced fibrinolytic activity of the peritoneum seems to be the main cause of postoperative adhesions. This prospective randomized trial compared the peritoneal fibrinolytic activity between laparoscopic and conventional colorectal resection. METHODS: Parietal peritoneal biopsy specimens were taken in standardized elective laparoscopic ( n=14) and conventional ( n=16) colorectal resections at the beginning and at the end of surgery. Activities and concentrations of tissue-plasminogen activator (tPA), plasminogen activator (PAI) type 1, and tPA/PAI complex were determined by ELISA kits. RESULTS: There was no difference in age, sex, or body mass index between the two groups. Perioperative tPA activity decreased in both groups without differences between the groups. Concentrations and activities of tPA, PAI-1, and tPA/PAI complex did not differ between the groups at any time. CONCLUSION: Peritoneal concentrations and activities of tPA, PAI-1, and tPA/PAI complex are similar during laparoscopic and conventional colorectal resections. A capnoperitoneum of 12 mmHg over 3 h did not affect the peritoneal fibrinolytic activity

Perspectives in sequential pneumatic compression of the lower extremities (SCD) for laparoscopic surgery.

During most cases of laparoscopic surgery, a pneumoperitoneum of 12-14 mm Hg CO2 is established. Although not always detected in healthy patients, a pneumoperitoneum will cause clinically relevant pathophysiological changes. Among other side effects, a pneumoperitoneum will alter the venous blood return from the lower extremities and depress cardiac function. Results from experimental and clinical studies concerning the influence of a pneumoperitoneum on venous blood return and cardiac function are reviewed and a simple model of cardiac function impairment during laparoscopic surgery with a pneumoperitoneum is presented. Sequential pneumatic compression of the lower extremities is effective in reducing venous stasis during and after conventional surgery. Several clinical trials determined the hemodynamic effect of intraoperative SCD (sequential compression device) during laparoscopic surgery. In the following text the results of these studies are summarized and possible implications for the clinical use of SCD in laparoscopic surgery are discussed. Although potential benefits of SCD-therapy have been shown only in studies of low methodological quality, intraoperative SCD-therapy is recommended during prolonged laparoscopic surgery.

Influence of the sampling technique on the measurement of peritoneal fibrinolytic activity.

OBJECTIVE: To establish the influence of the peritoneal sampling technique on the measurement of fibrinolytic capacity. DESIGN: Clinical study. SETTING: University hospital, Germany. SUBJECTS: 40 peritoneal biopsy specimens were taken from 10 patients who were having elective colorectal resections. INTERVENTIONS: Peritoneal biopsy specimens were taken either with a biopsy punch (n = 20) or manually with forceps and scissors (n = 20). MAIN OUTCOME MEASURES: Extent of agreement in fibrinolytic activities between specimens taken with biopsy punch and manually. Major endpoint-peritoneal tissue plasminogen activator (t-PA) activity. Minor endpoints-peritoneal tissue plasminogen activator concentration, and concentration and activity of plasminogen activator inhibitior type 1 (PAT-1). RESULTS: Intra-assay agreement and the extent of agreement between the groups were evaluated by the method of Bland and Altman. Correlation of repeated measurements of t-PA and PAI-1 concentrations and activities from the same sample using the same ELISA kit was high (r = 0.93-0.99, p < 0.01). t-PA activities and concentrations between the groups correlated poorly (r= 0.60 and 0.66, p < 0.01) while no correlation at all was seen for PAI-1 concentration and activity between the groups (r = 0.6 and 0.1, p = 0.2 and 0.9). The mean differences between the groups ranged from -27% to -4.8%. CONCLUSION: The sampling technique considerably affects the measurement of peritoneal fibrinolytic activity.

Cardiopulmonary changes during laparoscopy and vessel injury: comparison of CO2 and helium in an animal model.

BACKGROUND: Injury of venous vessels during elevated intraperitoneal pressure is thought to cause possible fatal gas embolism, and helium may be dangerous because of its low solubility. METHODS: Twenty pigs underwent laparoscopy with either CO2 (n=10) or helium (n=10) with a pressure of 15 mm Hg and standardized laceration (1 cm) of the vena cava inferior. After 30 s, the vena cava was clamped, closed endoscopically by a running suture and unclamped again. During the procedure changes of cardiac output (CO), heart rate (HR), mean arterial pressure (MAP), central venous pressure (CVP), pulmonary artery pressure (PAP), pulmonary artery wedge pressure (PAWP), end tidal CO2 pressure (PETCO2), and arterial blood gas analyses (pH, pO2 and pCO2) were investigated. RESULTS: No animal died during the experimental course (mean blood loss during laceration: CO2, 157+/-50 ml; helium, 173+/-83 ml). MAP and CO values showed a decrease after laceration of the vena cava in both groups that had already been completely compensated for before suturing. PETCO2 increased significantly after CO2 insufflation (P<0.01), while helium showed no effect. Laceration of the vena cava caused no significant changes in PETCO2 values in either group. Significant acidosis and an increase of pCO2 were only found in the CO2 group. CONCLUSIONS: The incidence of gas embolism during laparoscopy and accidental vessel injury seems to be very low. With the exception of acidosis and an increase of PETCO2 in the CO2 group, there were no differences in cardiopulmonary function between insufflation of CO2 and helium.

[Tolerance of early oral feeding after operations of the lower gastrointestinal tract]. / Verträglichkeit eines frühen oralen Kostaufbaus nach Operationen am unteren Gastrointestinaltrakt.

INTRODUCTION: Oral feeding is usually offered following surgery of the lower gastrointestinal tract when clinical signs of normal intestinal motility are present. However, some studies have shown that early oral feeding is well tolerated with low morbidity. METHODS: A prospective cohort study was performed to evaluate whether early oral feeding according to a standardized schedule is tolerated under normal clinical circumstances. One hundred consecutive patients following small- or large-bowel resection with anastomosis were offered fluids on post-operative day 1, soup on post-operative day 2, mashed food on post-operative day 3 and a regular diet on post-operative day 4. Parenteral nutrition was only given if necessary. Tolerance of oral feeding and the amount of food were checked twice a day. End points of the study were nausea (VAS score 1-100), vomiting (> 200 ml), reinsertion of a nasogastric tube, level of food intake, parenteral nutrition (ml), appetite and well-being. RESULTS: Loop ileostomies were done in 21 patients, colonic resections above the sigmoid in 32, and sigmoid and rectal resections in 47. The average age was 63 +/- 13 years. The frequency of nausea was less than 30% and of vomiting less than 10%. Only in two cases was a nasogastric tube inserted. Forty-three percent of all patients tolerated feeding very well according to the schedule. On post-operative day 3 more than 60% tolerated oral intake, on post-operative day 4, 74% and on post-operative day 5, 88%. Only 22% of the patients needed parenteral fluids on post-operative day 4. The first bowel movement was noted after 2.8 +/- 1.1 days. Surgical complications were documented in 18 patients and general complications in 6 patients. CONCLUSION: Most patients tolerated early oral feeding very well according to the schedule with low morbidity. Therefore, early feeding is now a substantial component of the postoperative treatment following small- or large-bowel resections.

Influence of nitrous oxide anesthesia on venous gas embolism with carbon dioxide and helium during pneumoperitoneum.

BACKGROUND: Gas embolism is a potential hazard during laparoscopic procedures. The aim of this study was to evaluate the effects of nitrous oxide (N(2)O) inhalation in the case of gas embolism with carbon dioxide (CO(2)) and helium during pneumoperitoneum. METHODS: For this study, 20 anesthetized pigs were ventilated with N(2)O (67% inspired) in O(2) (n = 10) or with halothane (0.7-1.5 inspired) in O(2) (n = 10). In each group, CO(2) (n = 5) or helium (n = 5) pneumoperitoneum was established and gas embolism induced at different rates (CO(2) at 0.5, 1, or 2 ml/kg/min; helium at 0.025, 0. 05, or 0.1 ml/kg/min) through the left femoral vein a maximum of 10 min while all hemodynamic parameters were continuously monitored. RESULTS: In the CO(2) group without N(2)O, all the animals tolerated rates of 0.5 and 1 ml/kg/min over the 10 min, whereas only 3 of 4 animals in the CO(2) group with N(2)O tolerated a rate of 0.5 ml/kg/min, and 2 of 4 animals a rate of 1 ml/kg/min. In the helium group without N(2)O, all the animals tolerated gas embolism at all rates, whereas in the helium group with N(2)O, 4 of 5 animals needed to be resuscitated at a rate of 0.1 ml/kg/min and one death occurred. CONCLUSIONS: Inhalation of N(2)O worsens the negative cardiovascular effects of venous CO(2) or helium gas emboli and increases the risk of emboli-induced death when CO(2) or helium are used to establish pneumoperitoneum. The volume of venous venous helium gas emboli causing such effects is substantially smaller than that for venous CO(2) gas emboli.

Randomized controlled trial to examine the influence of thoracic epidural analgesia on postoperative ileus after laparoscopic sigmoid resection.

BACKGROUND: The aim of the study was to evaluate whether perioperative epidural analgesia had any effect on the duration of postoperative ileus after laparoscopic sigmoid resection. METHODS: Twenty patients were randomized to surgery either with (group 1; n = 10) or without (group 2; n = 10) thoracic epidural analgesia. The major endpoint of the study was the time to the first postoperative bowel movement. Secondary endpoints were the interval until oral feeding was tolerated, incidence of postoperative vomiting, postoperative analgesic consumption use of patient-controlled analgesia (PCA) until the fourth day after operation, subjective pain perception and the incidence of epidural-related side-effects. RESULTS: Age, sex and American Society of Anesthesiologists classification were similar in the two groups. The first bowel movement was documented after a median of 54 (95 per cent confidence interval 32-127) h in group 1 and 77 (31-99) h in group 2 (P = 0.8). Oral feeding without additional parenteral therapy was tolerated after 48 (40-64) h in group 1 and after 56 (48-64) h in group 2 (P = 0.6). Postoperative vomiting occurred in two patients from each group. During epidural therapy the use of PCA was lower in group 1 (0.30 (0.19-0.96) mg morphine per kg) than in group 2 (0.56 (0.37-0. 80) mg/kg) (P < 0.05). Postoperative pain perception during rest and while coughing was similar in both groups. Three patients experienced reversible side-effects of epidural therapy (motor deficit, two patients; bladder dysfunction, one). CONCLUSION: Perioperative thoracic epidural analgesia did not have a clinically relevant effect on the duration of postoperative ileus after laparoscopic sigmoid resection.

[Effects of argon gas embolism during pneumoperitoneum]. / Auswirkungen von Argon-Gasembolien während eines Pneumoperitoneums.

In a porcine model, ten animals with a mean body weight of 18.9 (15-24) kg were exposed either to intravenous boli of 10, 20, and 30 ml argon (n = 5) or CO2 gas (n = 5). Gas embolism with argon led to increased pulmonary artery pressure (P > 0.001) and induced a decrease in end tidal CO2 (P < 0.001) and reduced cardiac output (P < 0.001) with a consecutive decrease in mean arterial pressure (P < 0.05). One animal died in cardiac shock after a 20 ml argon gas embolism and another after a 30 ml argon bolus. A third animal recovered after resuscitation with noradrenaline after a 30 ml argon bolus. Animals in the CO2 group receiving 10, 20, or 30 ml bolus neither required resuscitation nor died. Hemodynamic parameters were not affected by a 10 to 30 ml bolus of CO2 gas. Thus, gases with a low solubility in blood like argon should not be used during procedures with an increased risk of gas embolism.