Laparoscopic surgery: pitfalls due to anesthesia, positioning, and pneumoperitoneum.

BACKGROUND: Laparoscopic procedures are increasing in number and extensiveness. Many patients undergoing laparoscopic surgery have coexisting disease. Especially in patients with cardiopulmonary comorbidity, pneumoperitoneum and positioning can be deleterious. This article reviews possible pitfalls related to the combination of anesthesia, positioning of the patient, and the influence of pneumoperitoneum in the course of laparoscopic interventions. METHODS: A literature search using Medline's MESH terms was used to identify recent key articles. Cross-references from these articles were used as well. RESULTS: Patient positioning and pneumoperitoneum can induce hemodynamic, pulmonary, renal, splanchnic, and endocrine pathophysiological changes, which will affect the entire perioperative period of patients undergoing laparoscopic procedures. CONCLUSION: Perioperative management for the estimation and reduction of risk of morbidity and mortality due to surgery and anesthesia in laparoscopic procedures must be based on knowledge of the pathophysiological disturbances induced by the combination of general anesthesia, pneumoperitoneum, and positioning of the patient.

Randomized double-blind, placebo controlled safety study of a low molecular weight heparinoid in patients undergoing transurethral resection of the prostate.

In preparation for an efficacy study, the effect of the low molecular weight heparinoid Org 10172 on postoperative blood loss was assessed in a randomized double-blind, placebo controlled study in patients undergoing transurethral resection of the prostate (TURP). Org 10172 and placebo were given twice daily as i.v. injection for three postoperative days starting one hour preoperatively. Three doses of Org 10172 (800, 1600, and 2400 anti-Xa units b.d.) were evaluated against placebo in three consecutive patient blocks respectively. Each block consisted of 20 patients, 15 receiving Org 10172 and 5 patients placebo. The study was discontinued after 9 patients of the third block had completed the protocol because of excessive urinary blood loss. Data analysis showed a dose-dependent increase in postoperative haemoglobin loss, this was not significant for the 800 anti-Xa units b.d. dosage but was significant in those patients treated with 1600 (p less than 0.05) and 2400 anti-Xa units b.d. (p less than 0.01). It was concluded that the heparinoid Org 10172 caused a dose dependent increase in urinary blood loss following TURP.

The effectiveness of a low molecular weight heparinoid in chronic intermittent haemodialysis.

A new low molecular weight heparinoid, Org 10172 was compared to heparin in a randomized single blind cross-over study in 55 patients with end-stage renal failure undergoing chronic intermittent haemodialysis. The heparinoid administered as a single pre-dialysis i.v. injection of 34.4 anti-Xa units/kg body weight was compared to standard heparin (loading dose 2,500 IU + continuous infusion of 1,800 IU/hr). Mean anti-Xa plasma levels reached were 0.55 and 0.94 anti-Xa units/ml midway dialysis respectively. All 110 dialysis procedures were successfully performed without clotting or bleeding complications. Analysis of the number of clotted hollow-fibres within the dialysers showed a slight statistically calculated advantage in favour of heparin. Clinically no difference was detected. In conclusion, the heparinoid seems to be a good alternative means of anticoagulation in haemodialysis. As it is administered as a single i.v. predialysis injection it will simplify the dialysis procedure.

The effect of different anaesthetic techniques on the incidence of thrombosis following total hip replacement.

We performed a retrospective analysis on the influence of three types of anaesthesia on the incidence of deep vein thrombosis (DVT) following total hip replacement (THR) in consecutive patients randomized to either the low molecular weight heparinoid Org 10172 (97 patients), or placebo (99 patients). Ninety patients were operated under epidural anaesthesia, 77 patients under psoas compartment block with additional inhalation anaesthesia, and 29 patients under general anaesthesia. DVT assessment was performed by bilateral venography between days 8 and 12 postoperatively. The overall incidence of DVT in the 196 patients was 37% in the epidural anaesthesia group, 35% in the psoas compartment block group, and 36% in the general anaesthesia group. Although the incidence of DVT in patients randomized to placebo was similar in the two anaesthesia groups (53%), there was an important reduction of the occurrence of proximal DVT by the heparinoid in the psoas compartment block group (from 20 to 0%), compared to the epidural anaesthesia group (from 27 to 18%) (p less than 0.0061). Significantly more minor wound hematomas occurred in the psoas compartment block group as compared to the epidural anaesthesia group (p less than 0.05). Synergism of thrombin generation inhibition by the heparinoid and inhibition of platelet aggregation at the damaged vessel wall, by high local concentrations of bupivacaine in the psoas compartment block technique, is proposed as a possible mechanism behind this observation.

The routine use of fresh frozen plasma in operations with cardiopulmonary bypass is not justified.

BACKGROUND: The negative influence of cardiopulmonary bypass on hemostasis has been documented. Although abnormalities in platelet function are reported as the major cause of postoperative blood loss related to this hemostasis defect, fresh frozen plasma is often used in operations with cardiopulmonary bypass because it is thought to contribute to the reduction of postoperative bleeding complications. This study was designed to evaluate the effect of the administration of fresh frozen plasma after cardiopulmonary bypass on blood loss, transfusion requirements, and a number of coagulation parameters. METHODS: In a prospective, randomized, double-blind clinical trial 50 patients (mean age 63 years; 35 men/15 women) undergoing elective operation with cardiopulmonary bypass were randomly assigned to one of two groups: group I (n = 24) received 3 units of fresh frozen plasma after operation and group II (n = 26) received an equal amount of Gelofusine plasma substitute. At seven points before, during, and after operation hemoglobin concentration, hematocrit level, thrombocyte count, and coagulation parameters were analyzed. Study endpoints were the volume of blood loss and the transfusion requirement. RESULTS: There were no significant differences between the two study groups in blood loss, transfusion requirement, coagulation parameters, or thrombocyte counts. CONCLUSION: The routine use of fresh frozen plasma in operations with cardiopulmonary bypass cannot be recommended.

Anticoagulant effects of a low molecular weight heparinoid (Org 10172) in human volunteers and haemodialysis patients.

Org 10172, a low MW heparinoid derived from animal intestinal mucosal tissue, has a mean molecular weight of 6500 D and a specific activity of 8.0 anti-Xa U/mg. Its elimination half-life after i.v. administration is 18 hours. Six human volunteers received repeated single i.v. injections of 800 and 3200 anti-Xa units of Org 10172, 5000 IU heparin or placebo. Bleeding time, platelet count and plasma beta thromboglobulin were not affected by Org 10172 or heparin. Heparin stimulated ADP-induced platelet aggregation (0.2 uM; p less than 0.05) and inhibited thrombin induced aggregation (0.3 U/ml; p less than 0.05), while the heparinoid lacked these effects. Heparin increased plasma platelet factor 4, whereas Org 10172 had no effect. In contrast to heparin Org 10172 had only a minor effect on the activated partial thromboplastin time and thrombin time, while both compounds induced anti-Xa activity in plasma. In a crossover study in six haemodialysis patients, both heparin and Org 10172 (34.4 and 22.4 anti-Xa units/kg/body weight) successfully prevented clotting of the extracorporeal circuit. Microscopical analysis of the artificial kidney membranes showed that the 34.4 unit Org 10172 dosage was as effective as heparin in preventing fibrin deposition. The haemostatic and coagulation effects were as expected from those observed in the volunteers except that there was a slower elimination of the plasma anti-Xa response. In addition heparin and Org 10172 (34.4 anti-Xa units/kg) inhibited the Xa-induced platelet aggregation (0.5 U/ml; p less than 0.01 and p less than 0.001 respectively).

Results of selective percutaneous controlled radiofrequency lesion for treatment of trigeminal neuralgia in 240 patients.

Trigeminal neuralgia may be treated in several ways. In the present study, the efficacy of a selective percutaneous radiofrequency (RF) neurolysis in the gasserian ganglion was evaluated in 240 patients. The recurrence rate after a single treatment was 28.3% within 2 years. After multiple treatments (n = 68), the recurrence rate had decreased to 8.3% (n = 20). Thus, the overall success rate at the end of the follow-up period was 91.7%. The mean follow-up period was 50 months (range 12-96 months). Except for corneal anesthesia in 3.7% of the patients, no serious complications occurred.

The effect of the administration of recombinant activated factor VII (NovoSeven) on perioperative blood loss in patients undergoing transabdominal retropubic prostatectomy: the PROSE study.

Transabdominal retropubic prostatectomy is associated with significant perioperative blood loss, often requiring blood transfusion. However, the administration of allogeneic blood and blood products may induce serious immunological or infectious complications. Several studies show that recombinant activated factor VII (rFVIIa; NovoSeven, Novo Nordisk A/S, Bagsvaerd, Denmark) induces short-term local hemostasis. This ongoing study will evaluate the safety and efficacy of rFVIIa on blood loss in patients with normal coagulation undergoing retropubic prostatectomy. Thirty-six patients will be randomized to three different dose levels and receive either rFVIIa as a single intravenous bolus dose or saline. Perioperative blood loss will be assessed from blood-volume suction containers and drains. Blood sample analysis, physical examination and electrocardiography will be performed postoperatively. Eighteen patients have enrolled in the study. Blood loss was 630-4455 ml (mean = 1698 ml), while the number of red cell transfusions varied between 0 and 4 units (mean = 0.9 units). None of the patients developed venous thromboembolism. An independent committee performed an interim analysis after patient 12 and identified a positive trend between treatment groups (not statistically significant). Although a single bolus injection of rFVIIa appears to decrease perioperative blood loss safely and effectively, definite conclusions must await study completion.

Cytomegalovirus infection in the pregnant women.

Cytomegaloviruses (CMV) commonly infect man but overt disease only occurs in few patients; in the vast majority the infection is subclinical. We report on a HIV-negative pregnant woman. She suffered from a life-threatening ulcerating colitis due to CMV infection for which laparotomy was indicated. The case history is presented and suggestions are given for the surgical treatment of gastrointestinal complications such as haemorrhage, toxic colitis and perforation. Although CMV disease usually occurs in immunocompromised patients such as AIDS patients and transplant recipients, one should always keep the possibility of CMV infection in mind. The gastrointestinal tract is one of the sites of infection where the colon and terminal ileum are most frequently involved in complications such as bleeding and perforation. Gastrointestinal complications of CMV infection, although rare, can be life threatening and often require extensive surgery.

Red blood cell velocity in nailfold capillaries during hyperbaric oxygenation.

Microcirculatory hemodynamics of the skin during hyperbaric oxygenation were assessed by determination of nailfold capillary red blood cell velocity (Vrbc). Under hyperbaric conditions a continuous increase in Vrbc was found. Control values, 0.43 +/- 0.12 mm. sec-1 (mean +/- sem), were significantly (P < 0.05) lower compared with Vrbc at the end of hyperbaric oxygenation (0.62 +/- 0.16 mm.sec-1).

Skeletal muscle PO2 in anaerobic soft tissue infections during hyperbaric oxygen therapy.

In the present study skeletal muscle PO2 measurements were performed in patients with gas gangrene and anaerobic soft tissue infections before, during and after hyperbaric oxygen therapy. Polarographic PO2 needle electrodes appeared to be suitable for application during different ambient pressures. We found that patients with gas gangrene revealed higher skeletal muscle PO2 values than patients with an anaerobic soft tissue infection. This may be explained by a higher metabolic rate within the anaerobically infected soft tissues. The higher PO2 values in gas gangrene may be caused by alpha toxins, affecting cellular and intracellular membranes thus destroying PO2 diffusion barriers.

Veno-venous bypass without systemic heparinization using a centrifugal pump: a blind comparison of a heparin bonded circuit versus a non heparin bonded circuit.

Veno-venous bypass without the use of systemic heparinization has recently become of increasing interest for application during liver transplantation and surgery on the large abdominal veins. However, possible adverse effects on blood components as demonstrated by means of hematologic and hemostatic parameters or on the occurrence of thromboembolic complications are until now not excluded. No consensus has been reached as to the efficacy of heparin coated circuits in those procedures. In the present study veno-venous bypass was performed for four hours in ten dogs using heparin coated and non coated circuits without further heparinization in a randomized blind fashion. No changes or significant intergroup differences were noted in the hematological and coagulation parameters. Macroscopic evaluation of the circuits revealed small strands of fibrin on all connector rims and clots in the center part of the pump head and at the cannula tips. The lungs showed two small emboli in large size pulmonary arteries and also two minor emboli in small size arteries. In four animals the emboli were equally divided between the two groups. As expected regarding the size of the clots no influences could be seen on hemodynamic or respiratory parameters. With Scanning Electronic Microscopy a monolayer of activated thrombocytes was observed on the surface of the bypass circuits in the coated as well as in the uncoated group. This study suggests that a veno-venous bypass without systemic heparinization is possible without serious damage to blood cellular elements or impressive activation of the coagulation system.(ABSTRACT TRUNCATED AT 250 WORDS)

[Excess mortality in critically ill patients after treatment with human albumin]. / Vergrote kans op overlijden van ernstig zieke patiënten na behandeling met humaan albumine?

According to the results of a systematic review of randomized clinical studies administration of human albumin to critically ill patients is associated with excess mortality, compared with withholding albumin or administration of crystalloid fluids. The study appears to be well done. Also, there are various explanatory pathophysiological mechanisms supporting the association. However, a favourable effect of albumin in certain patient groups cannot be excluded. Alternatives to albumin are available in most clinical situations, but unfortunately, they are not completely without drawbacks. The use of albumin has to be limited; it might only be abolished when a better effect of other fluids, such as synthetic solutions, is demonstrated.