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Abstract: Background: Plasma hyaluronan binds to fibrinogen, affecting intravascular fibrin polymerization and fibrin clot formation. It has been hypothesized that alterations in fibrin clot formation influence the risk of thromboembolism in those undergoing surgery. The aim of this study is to quantify the intravascular components, especially plasma hyaluronan levels, in laparoscopic and conventional colorectal resections that contribute to thromboembolism formation. Methods: Prospective cohort analysis of consecutive patients which were participating in the prospective randomized multi-center trial Lapkon II comparing the long-term effects of laparoscopic and conventional resection for colon cancer. Plasma samples were obtained from 15 patients at the beginning and the end of laparoscopic or conventional colorectal resections. Concentrations and activities of tissue plasminogen activator(t-PA), plasminogen activator inhibitor type 1(PAI-1), t-PA/PAI complex, fibrinogen, d-dimers and hyaluronan were determined by using commercial enzyme-linked immunosorbent assay (ELISA) kits. Results: No differences in age, sex and type of resection between the laparoscopic and conventional-surgery groups were observed. Laparoscopic procedures lasted longer (p < 0.05). Concentration and activities of t-PA, PAI-1, t-PA/PAI complex, fibrinogen and d-dimers did not vary between the two groups. Plasma hyaluronan decreased from 28.6 to 17.9 IU/ml (p < 0.05) during laparoscopic compared to conventional procedures. Plasma hyaluronan levels were significantly different at the end of operation between the two groups (p < 0.05) . Conclusions: Plasma hyaluronan levels were decreased in patients undergoing laparoscopic colorectal resections, compared to those undergoing conventional procedures. Therefore, interactions between plasma hyaluronan and fibrinogen may be lower, with a sequential decrease in fibrin polymerization, and a possibly reduced risk of deep venous thrombosis.

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 β1-blocker esmolol; and third, a decrease in mean arterial pressure (MAP) by the vasodilator sodium nitroprusside.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.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.Optimizing volume load is effective for minimizing hemodynamic changes during CP in the head-up and in head-down positions. In general, β1-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.

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.

Background: The pneumoperitoneum is the crucial element in laparoscopic surgery. Different clinical problems are associated with this procedure, which has led to various modifications of the technique. The aim of this guideline is to define the scientifically proven standards of the pneumoperitoneum. Methods: Based on systematic literature searches (Medline, Embase, and Cochrane), an expert panel consensually formulated clinical recommendations, which were graded according to the strength of available literature evidence. Recommendations: Preoperatively, all patients should be assessed for the presence of cardiac, pulmonary, hepatic, renal, or vascular comorbidity. Presupposing appropriate perioperative measures and surgical technique, there is no reason to contraindicate pneumoperitoneum in patients with peritonitis or intraabdominal malignancy. During laparoscopy, monitoring of end tidal CO2 concentration is mandatory. The available data on closed- (Veress needle) and open-access techniques do not allow us to principally favor the use of either technique. Using 2 to 5-mm instead of 5 to 10-mm trocars improves cosmetic result and postoperative pain marginally. It is recommended to use the lowest intraabdominal pressure allowing adequate exposure of the operative field, rather than using a routine pressure. In patients with limited cardiac, pulmonary, or renal function, abdominal wall lifting combined with low-pressure pneumoperitoneum might be an alternative. Abdominal wall lifting devices have no clinically relevant advantages compared to low-pressure (5–7 mmHg) pneumoperitoneum. In patients with cardiopulmonary diseases, intra- and postoperative arterial blood gas monitoring is recommended. The clinical benefits of warmed, humidified insufflation gas are minor and contradictory. Intraoperative sequential intermittent pneumatic compression of the lower extremities is recommended for all prolonged laparoscopic procedures. For the prevention of postoperative pain a wide range of treatment options exists. Although all these options seem to reduce pain, the data currently do not justify a general recommendation.

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 CO2gas (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 CO2group 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 CO2gas. Thus, gases with a low solubility in blood like argon should not be used during procedures with an increased risk of gas embolism. In einer experimentellen Studie wurde bei 10 Schweinen mit einem mittleren Körpergewicht von 18,9 (15–24) kg eine intravenöse CO2- oder Argon-Embolie mit 10, 20 und 30 ml Gas durchgeführt. Das invasive Monitoring zeigte bei der Gasembolie mit Argon im Gegensatz zur Gasembolie mit CO2einen stärkeren Anstieg des pulmonal arteriellen Drucks (p< 0,001), einen stärkeren Abfall des endexspiratorischen CO2(p< 0,01), des Herzminutenvolumens (p< 0,01) und des mittleren arteriellen Drucks (p< 0,01). In der Argon-Gruppe (n= 5) starben zwei Tiere nach 20 bzw. 30 ml Bolusgabe. Ein weiteres Tier konnte nach Gabe von 30 ml Bolus erfolgreich reanimiert werden. In der CO2-Gruppe (n= 5) starb weder eines der Tiere noch war eine Reanimation erforderlich. Wenig lösliche Gase wie Argon sollten in Situationen mit erhöhtem Risiko einer Gasembolie nicht angewendet werden.

Summary: Whether a prophylactic drain is useful after elective colorectal resections is questionable. The purpose of this prospective study was to evaluate the role of postoperative drainage following elective colorectal resections. Hundred consecutive laparoscopic and open elective resections for colorectal cancer were prospectively recorded. Seventy-four resections were accomplished conventionally, 22 laparoscopically and 4 laparoscopically assisted. The day of removal of the drainage was at the discretion of the surgeon. In 28 patients, drainage was removed after 1 day, in 34 patients after 2 days, in 20 patients after 3, and in 18 patients after 4 or more days. The preoperative risk (ASA class), age, body mass index (BMI), tumor stage, tumor location, intraoperative blood loss, and operative time were not significantly different in relation to duration of drainage. The postoperative surgical complications included 4 anastomotic leakages, 1 bleeding requiring reoperation and 5 wound infections. The drainage was neither able to diagnose bleeding nor to prevent reoperation in patients with anastomotic leaks. A prophylactic drain after colorectal resections is only recommended in selected cases.

Summary.: To evaluate whether laparoscopic appendectomy shortens the convalescence and the postoperative period until return to work when compared to conventional appendectomy, a prospective randomized trial was performed. The major endpoint of the study was the time until return to work; minor endpoints were postoperative pain, fatigue, operative time and postoperative morbidity. In all, 54 patients with a mean age of 29.5 ± 10.1 years were randomized to open (n = 28) or laparoscopic appendectomy (n = 26). Age, sex, body mass index (BMI), American Society of Anesthesiology (ASA) rating, job status as well as histologic degree of inflammation of the appendix were comparable in the two groups. Operative time was 59.2 ± 15.8 min for laparoscopic and 59.8 ± 24.4 min for conventional appendectomy (P = 0.9). Some 16 laparoscopic appendectomies (62 %) were performed by board-certified surgeons, while 23 conventional appendectomies (82 %) were performed by residents (P = 0.003). Postoperative morbidity was comparable between the two groups. After laparoscopic appendectomy, pain was rated significantly lower on the first, second and fourth postoperative day when compared to the conventional group. There were no difference in postoperative fatigue between the groups. Time to return to work was 17.0 ± 6.2 days in the laparoscopic group and 18.2 ± 6.0 days in the conventional group (p = 0.5). Laparoscopic appendectomy has no advantages in terms of convalescence and time to return to work when compared to open appendectomy and should therefore be limited to selected cases.