Michael Felfernig

Ketamine is a strong acting analgesic drug, used mainly in trauma and emergency medicine settings, as well as for minor procedures. Its pharmacological properties make it a useful drug for military anaesthesia. Ketamine acts by blocking activation of the spinal and supraspinal NMDA-type glutamate and opioid receptors. It produces dissociative anaesthesia, which means that patients might remain conscious, though insensitive to pain and amnesic (anterograde), Dysphoria and hallucinations are the main side effects in the early recovery period. We studied the incidence of post operative nausea and vomiting, vigilance disturbances and haemodynamic instability during combined ketamine and propofol anaesthesia.No patient suffered from postoperative nausea and vomiting. No haemodynamic instabilily could be observed in any of the patients. Tie interesting point is that though there were no unpleasant emergence phenomenons, no patient reached the preoperative state of vigilance within two hou...

... Physiologyc basis of a bedside screening test. JAMA 1966: 196: 754-756. 15. Tapson VF,Witty LA. Massive pulmonary embolism. Diag-nostic and therapeutic strategies. Clin Chest Med 1995: 16 16. Sdunid C, Zietlow S, Wagner TO, Laas J, Borst HG. ...

In dieser Kasuistik wird die Hämostase eines Patienten während orthotoper Lebertransplantation (OLT) und einer intraoperativen Blutungskomplikation mit Massivtransfusion beschrieben. Design: Das Gerinnungsmonitoring bestand aus der bettseitigen Thromboelastographie, der Messung der Thrombozytenfunktion in vitro mittels Thrombostat und der Bestimmung der Routinetests der plasmatischen Gerinnung sowie der retro-spektiven Analyse der Einzelgerinnungsfaktoren. Ergebnisse: Die Veränderungen der Hämostase während OLT waren bis zur Reperfusion des Spenderorgans typisch für diese Operation. Aufgrund einer Lumeninkongruenz im Bereich der Anastomose der Vena cava mit massiver chirurgischer Blutung mußte das Transplantat zur plastischen Rekonstruktion neuerlich ausgeklemmt und mit University-of-Wisconsin-Lösung gespült werden. Nach der zweiten, technisch komplikationslosen Reperfusion verschlechterte sich der Gerinnungsstatus drastisch. Vor allem eine Störung der Thrombozytenfunktion und eine ...

This prospective randomized study investigated the influence of normotensive and hypotensive general anesthesia on platelet aggregability, intraoperative blood loss and parameters of plasmatic coagulation during extensive orthognathic surgery. A total of 30 patients were randomly allocated for either normotensive anesthesia maintained by continuous infusion of propofol and remifentanil (NORMO, n=10) or hypotensive anesthesia, whereby hypotension was induced by increasing the infusion rate of remifentanil (HYPO-R, n=10) or by administration of nitroglycerin (HYPO-N, n=10). Whole blood platelet aggregability was significantly reduced during hypotension compared to normotensive anesthesia (P<.01, HYPO-N and HYPO-R vs. NORMO). Mean arterial blood pressure during hypotension correlated well with adenosinediphosphate- (R=.712, P<.001) and collagen-induced platelet aggregability (R=.685, P<.001). Within hypotensive study groups, postoperative fibrinogen levels were significantly different, whereas intraoperative platelet aggregability, postoperative platelet count, prothrombin time, activated partial thromboplastin time and antithrombin levels were not different. Normotensive anesthesia, however, caused significant decreases in platelet count (-29%), prothrombin time (-24%), fibrinogen (-41%) and antithrombin (-28%) and a significant prolongation in activated partial thromboplastin time (+21%) and thrombin time (+18%). There was a trend to reduced intraoperative blood loss in hypotensive study groups; however, differences were not significant. In conclusion, induced hypotension--independent of substances used for induction of hypotension--reduces intraoperative platelet aggregability, subsequently protecting the coagulation system against subclinical consumption coagulopathy. Induced hypotension-caused platelet dysfunction does not lead to an increased intraoperative blood loss, but quite on the contrary shows a trend to reduced intraoperative blood loss, possibly by preventing platelet-induced subclinical consumption coagulopathy.

To investigate anticoagulation with prostacyclin (prostaglandin I2 [PGI2]) and/or heparin during continuous venovenous hemofiltration, and the role of in vitro tests of primary hemostasis in controlling anticoagulation. Prospective, randomized, controlled trial. Intensive care unit. Forty-six consecutive, critically ill, mechanically ventilated patients with postoperative acute renal failure. Anticoagulation of the patient's blood was accomplished using heparin (6.0 +/- 0.3 IU/kg/hr for group 1), PGI2 (7.7 +/- 0.7 ng/kg/min for group 2), or both PGI2 and heparin (6.4 +/- 0.3 ng/kg/min, 5.0 +/- 0.4 IU/kg/hr, respectively, for group 3), administered into the extracorporeal line before the hemofilter during continuous venovenous hemofiltration. After Ethics Committee approval and informed consent were obtained, tests of primary and secondary hemostasis, plasma concentrations of 6-ketoprostaglandin F1 alpha (by radioimmunoassay), and hemodynamic measurements were performed before hemofiltration and 24 hrs after hemofiltration. In groups 1 and 3, hemodynamic parameters remained stable, whereas in group 2 (the PGI2 group), there were significant reductions in systemic and pulmonary vascular resistances and mean arterial pressure. Platelet function was unchanged in group 1, and was inhibited in groups 2 and 3. Corresponding with the prolongation of in vitro bleeding time, the 6-ketoprostaglandin F1 alpha concentration was increased, indicating an effective inhibition of platelet aggregation within the hemofilter. Platelet counts remained stable in all patients. Plasma coagulation tests were stable in groups 2 and 3, and were prolonged in group 1. In all patients, no major bleeding complications were observed and there was no clinically important bleeding. Mean hemofilter duration lasted longest in group 3. Blood urea nitrogen and circulating creatinine concentrations decreased significantly in groups 2 and 3 within the study period. Patients receiving both PGI2 and heparin showed better hemodynamic profiles and enhanced hemofilter duration compared with the other groups and no bleeding complications were observed. Therefore, we recommend anticoagulation with PGI2 and heparin during continuous venovenous hemofiltration with close monitoring of platelet function, coagulation profile, and overall hemodynamics.

Hemodialysis activates both platelets and leukocytes, which play a role in the development of multiple organ dysfunctions in critically ill patients. Prostacyclin inhibits both cell types. To examine the hypothesis that prostacyclin prevents cellular activation during clinical hemofiltration, we investigated the expression of activation markers on platelets and leukocytes using whole blood flow cytometry. Prospective, randomized, double-blind, controlled trial. Intensive care unit. A total of 24 consecutive, critically ill, mechanically ventilated patients with acute renal failure secondary to sepsis or major surgery. For anticoagulation during hemofiltration, patients received either unfractionated heparin or unfractionated heparin and prostacyclin (5 ng x kg(-1) x min(-1)). Anticoagulants were administered into the extracorporeal circuit before the hemofilter. Blood samples were obtained from an arterial catheter before hemofiltration and from the inlet and outlet lines of the extracorporeal circuit at 1 and 24 hrs during hemofiltration. Expression of GP IIb-IIIa and P-selectin on adenosine diphosphate-activated platelets and platelet-leukocyte aggregation were significantly lower after the passage of blood through the hemofilter in patients receiving an extracorporeal infusion of prostacyclin plus heparin when compared with control patients receiving heparin only. There were no statistically significant differences in the expression of CD11b on leukocytes between the two groups. These findings suggest that prostacyclin reversibly inhibits platelet function by diminishing the expression of platelet fibrinogen receptors and P-selectin and reduces heterotypic platelet-leukocyte aggregation during clinical hemofiltration. However, prostacyclin fails to inhibit leukocyte activation at clinically relevant doses.

Endotracheal intubation has been performed during the administration of propofol anesthesia without neuromuscular blockade. In this study, we determined the propofol dose required for conventional nasotracheal or for fiberoptic nasotracheal intubation of all patients. Thirty-two patients undergoing maxillofacial surgery were randomly assigned to the conventional (n = 16) or to the fiberoptic (n = 16) intubation group. In both groups, anesthesia was induced by using IV fentanyl and IV titrated propofol according to clinical need (spontaneous respiration rate, verbal response). An endotracheal tube was placed nasally in the pharynx and the vocal cords visualized by using a fiberscope inserted via the tube. In the conventional group, the larynx was visualized additionally with a laryngoscope blade (Miller). In both groups propofol was titrated until the vocal cords opened. Patients were tracheally intubated, and the propofol dose was recorded. In all patients, the trachea could be intubated without the use of muscle relaxants. Considerable interindividual differences of dose requirements were observed. The amount of propofol required in the conventional group was significantly (P < 0.0001) larger (median +/- SD: 2.74 +/- 1.59 mg/kg; range 1.95-7.07 mg/kg) than in the fiberoptic group (1.37 +/- 0.59 mg/kg; 0.72-2.86 mg/kg). Hemodynamics remained stable in all patients. Postintubational hoarseness occurred in three patients of each group. Fiberoptic nasal intubation without a muscle relaxant can be facilitated with significantly smaller and more predictable dosages of propofol than conventional nasal endotracheal intubation. The possibility of titrating the propofol dose under assisted ventilation until the vocal cords open during fiberoptic nasotracheal intubation and the better predictability of the required dose favors the fiberoptic approach. In this study, contrary to all preceding studies using predefined doses of propofol and opioids, we determined the minimal required propofol dose in combination with fentanyl for conventional or fiberoptic nasotracheal intubation without muscle relaxants.

Ultrasonographic observation of peripheral nerve blocks enables direct visualization of the spread of local anesthetic around the targeted nerves. Similarly, ultrasonography may be used to determine the site of local anesthetic placement when landmark-based techniques are used. We performed a study to determine the actual location of local anesthetic when ilioinguinal/iliohypogastric nerve blocks are performed using landmark-based techniques in children in an attempt to explain a failed block. After induction of general anesthesia (1 minimum alveolar anesthetic concentration halothane and laryngeal mask airway), 62 children scheduled for inguinal surgery received an ilioinguinal/iliohypogastric nerve block based on standard anatomical landmarks. Ultrasonography was then used to determine the actual location of local anesthetic placement. The anesthesiologist performing the block was blinded to the ultrasonographic investigation. Successful blocks were recorded either when the local anesthetic surrounded the nerves or were based on clinical signs after skin incision. In 14% of the blocks, the local anesthetic was administered correctly around the nerves resulting in successful blocks. In the remaining 86%, the local anesthetic was administered in adjacent anatomical structures (iliac muscle 18%, transverse abdominal muscle 26%, internal oblique abdominal muscle 29%, external oblique abdominal muscle 9%, subcutaneous 2%, and peritoneum 2%), and 45% of these blocks failed. Accurate placement of local anesthetic around the ilioinguinal/iliohypogastric nerves in children is seldom possible when landmark-based techniques are used. In the majority of patients, the local anesthetic was inaccurately placed in adjacent anatomical structures with unpredictable block results.

Background: Hydroxyethyl starches (HES) have been shown to decrease clot strength and to increase coagulation times assessed by thromboelastography (TEG). HES with minimal anticoagulant side‐effects is beneficial for plasma volume expansion in the perioperative setting. A comparison of the in vivo effects of high, middle and low molecular weight HES solutions on TEG variables has not been performed so far.Methods: Blood was obtained before and after intravenous infusion (10 ml kg−1) of either saline, HES 70/0.5/4 (molecular weight in kDa/degree of substitution/C2:C6 ratio), HES 130/0.4/9, HES 200/0.6/9.4, or HES 450/0.7/4.6 in 50 otherwise healthy patients. Thromboelastography was performed in 360 µl of 1% celite activated citrated whole blood after recalcification.Results: HES 450/0.7/4.6 prolonged reaction time indicating impairment of the plasmatic coagulation system. TEG parameters indicative for platelet function, including angle α, maximum amplitude and coagulation time, deter...