Paravertebral blocks reduce the risk of postoperative urinary retention in inguinal hernia repair.

PURPOSE: Inguinal hernia repair and general anesthesia (GA) are known risk factors for urinary retention. Paravertebral blocks (PVBs) have been utilized to facilitate enhanced recovery after surgery. We evaluate the benefit of incorporating PVBs into our anesthetic technique in a large cohort of ambulatory patients undergoing inguinal hernia repair. METHODS: Records of 619 adults scheduled for ambulatory inguinal hernia repair between 2010 and 2015 were reviewed and categorized based on anesthetic and surgical approach [GA and open (GAO), GA and laparoscopic (GAL), PVB and open (PVBO), and GA/PVB and open (GA/PVBO)]. Patients were excluded for missing data, self-catheterization, chronic opioid tolerance, and additional surgical procedures coinciding with hernia repair. Risk factors associated with the primary outcome of urinary retention were examined using logistic regression. RESULTS: PVBO (n = 136) had significantly lower odds than GAO of experiencing urinary retention (odds ratio 0.16; 95% CI 0.05-0.51); overall (P < .01), with 4.4% (n = 6) of the patients in the PVBO group having urinary retention versus 22.6% (n = 7) with GAO. Expressed as intravenous morphine equivalences, the PVBO group had the lowest median opioid use (5 mg), followed by GA, PVB, and open (7.5 mg); GAO 25 mg; and GAL 25 mg. Also, 30% (n = 41) of the PVBO group required no opioid analgesia in the postanesthesia care unit. CONCLUSIONS: PVBs as the primary anesthetic or an adjunct to GA is the preferred anesthetic technique for open inguinal hernia repair as it facilitates enhanced recovery after surgery by decreasing risk of urinary retention, opioid requirements, and length of stay.

The synthetic pentasaccharide fondaparinux reduces coagulation, inflammation and neutrophil accumulation in kidney ischemia-reperfusion injury.

Ischemia-reperfusion (I/R) injury is associated with activation of coagulation and inflammation. Interestingly, various anticoagulants have been shown to reduce both coagulation and inflammation in animal models of kidney I/R injury. Fondaparinux is a synthetic pentasaccharide that selectively inhibits factor Xa (FXa) in the coagulation cascade. The aim of this study was to investigate the effect of fondaparinux in a lethal murine model of kidney I/R injury. A murine model of kidney I/R was established. In this model, we measured activation of the coagulation cascade and induction of inflammation. Administration of fondaparinux to I/R-injured mice reduced fibrin deposition in the kidney, reduced serum creatinine levels and increased survival from 0 to 44% compared with saline-treated control mice. Fondaparinux also reduced interleukin-6 and macrophage inflammatory protein-2 expression and decreased neutrophil accumulation in the injured kidneys. Finally, we showed that fondaparinux reduced thioglycollate-induced recruitment of neutrophils into the peritoneum and inhibited the binding of U937 cells to P-selectin in vitro. Our data suggest that fondaparinux reduces kidney I/R injury primarily by inhibiting the recruitment of neutrophils.

Hirudin elimination by hemofiltration: a comparative in vitro study of different membranes.

BACKGROUND: Recombinant hirudin (r-hirudin) is a highly specific and selective thrombin inhibitor. Since 1997, it has been approved for the treatment of heparin-induced thrombocytopenia (HIT type II). Renal function impairment drastically prolongs the elimination half-life time. In cases of bleeding or overdosage, there is currently no antidote available. Hemofiltration has been reported to be useful in r-hirudin elimination. In this study, we determined sieving coefficients (SCs) and drug clearances for two different hemofilters currently used in clinical medicine and intensive care. METHODS: We developed an in vitro postdilution hemofiltration model using 500 ml heparinized (2 IU unfractionated heparin/ml) fresh human blood and bicarbonate substitution fluid. The investigated membranes were high-flux polysulfone F50 (1.0 m2, Fresenius) and AN69 Nephral 200 (1.05 m2, Hospal Cobe). After equilibration, a bolus of Lepirudin was injected into the postfilter port to achieve a r-hirudin blood level of approximately 15 microg/ml. Serial blood and ultrafiltrate samples were taken for the determination of hirudin levels (chromogenic assay) and control parameters. SC and clearances were calculated according to standard formulae. RESULTS: The observed SCs and clearances differed significantly between F50 and Nephral 200 (0.60+/-0.17 and 21.0+/-5.9 ml/min, respectively, vs. 0.44+/-0.09 and 15.5+/-3.0 ml/min, respectively; P = 0.001). The determination of prothrombin fragments showed no coagulation activation during the experiments. The hematocrit values remained stable. CONCLUSIONS: Our data show that r-hirudin can be eliminated by hemofiltration. The elimination obviously depends on the membrane material with high-flux polysulfone being more effective than AN69. These findings may be important in cases of overdosage and for r-hirudin dosage guidelines in continuous hemofiltration.

Color-coded duplex sonography study of arteriovenous fistulae and pseudoaneurysms complicating percutaneous renal allograft biopsy.

BACKGROUND: The exact incidence and clinical impact of arteriovenous fistulae (AVF) and pseudoaneurysms as complications emerging from renal allograft biopsy are not well established. We therefore conducted a prospective study using color-coded duplex sonography (CCDS) to determine the frequency, clinical presentation and spontaneous occlusion rate of biopsy-related AVF and pseudoaneurysms in kidney transplant recipients. METHODS: We investigated 72 consecutive patients undergoing renal allograft biopsy using an automated biopsy technique. CCDS was performed before, immediately after and up to more than 6 months after biopsy. The diagnosis of AVF was based on the presence of perivascular vibration artifacts and detection of typical Doppler curves. Pseudoaneurysms were diagnosed based on the presence of"to-and-fro" signals. RESULTS: In 5 patients (6.9%), an AVF was detectable before biopsy. Post-biopsy AVF were found in 12 additional patients (16.7%) with a spontaneous occlusion rate of 50% within 48 hours and 75% after 4 weeks. Three (25%) AVF persisted longer than 1 year. Four patients (5.6%) were found to have pseudoaneurysms. All pseudoaneurysms were located closely to AVF and closed spontaneously. None of the post-biopsy AVF and pseudoaneurysms required specific therapy. In 2 patients (2.8%), allograft biopsy lead to significant hemorrhage independent of AVF or pseudoaneurysms. CONCLUSION: These results indicate that post-biopsy AVF and pseudoaneurysms are a frequent finding after automated renal allograft biopsy. The natural history of these lesions shows a high rate of early occlusion. The present data fail to demonstrate significant clinical impact of AVF and pseudoaneurysms after renal allograft biopsy.

Is there a role for hemoperfusion/hemodialysis as a treatment option in severe tricyclic antidepressant intoxication?

OBJECTIVE: Suicidal self-poisoning with tricyclic antidepressants like doxepin is a major therapeutic problem in emergency medicine with a high fatality rate. Deaths are mainly caused by cardiotoxicity with arrhythmias, intraventricular conduction disturbances and myocardial depression. For treatment, alkalinization and hypertonic saline are recommended. The role of extracorporeal, treatment procedures is not clear. The possible benefit of hemoperfusion/hemodialysis is discussed in a case report with respect to the published literature. CASE REPORT: After ingestion of an amount of at least 5000 mg doxepin a 37-year-old man with endogenous depression developed cardiac arrest. After preclinical resuscitation with prolonged external cardiac massage, he was admitted to the intensive care unit with persistently severe hypotension and wide QRS complexes (230-260 ms). Despite fluid load, alkalinization, hypertonic saline and high-dose vasoactive substances the patient's condition did not improve. Hemoperfusion over hemoresin combined with hemodialysis led to an impressive clinical improvement with shortening of QRS duration (from 230 to 120 ms) and hemodynamic stabilization. The patient fully recovered without neurologic deficits. CONCLUSION: We report a successful treatment with hemoperfusion over hemoresin and hemodialysis in a patient with life-threatening doxepin poisoning intractable with the generally recommended treatment. In such acute TCA intoxication with severe cardiotoxicity, hemoperfusion/hemodialysis should be considered a potential treatment option, as the "toxicokinetics" of drugs may totally differ from their usual pharmacokinetic behaviour. Experimental and clinical studies are needed to clarify the toxicokinetics of TCA in order to improve the therapeutic approach.

[Citrate anticoagulation in acute renal replacement therapy : Method of choice]. / Zitratantikoagulation in der akuten Nierenersatztherapie : Methode der Wahl.

BACKGROUND: Anticoagulation is prerequisite for efficient continuous renal replacement therapy (CRRT). Premature clotting of the extracorporeal system leads to therapy interruptions, is costly, and causes relevant blood losses. REGIONAL ANTICOAGULATION: Regional citrate anticoagulation (RCA) achieves reliable coagulation inhibition and is clearly superior to heparin with regard to filter survival time. Due to its mode of action, a bleeding risk can be excluded. RCA with the commercial machine solutions is safe and has been promoted as the new standard anticoagulant for CRRT. Bioincompatibility reactions like leukocyte degranulation and complement system activation are ameliorated under RCA. DISCUSSION: An assumed survival advantage of RCA could not be confirmed. In case of severe liver insufficiency and lactic acidosis, RCA can lead to metabolic complications. Despite calcium supplementation, the calcium net balance of RCA is often negative. Long treatment durations can therefore cause secondary hyperparathyroidism and in extreme cases osteomalacia. RCA is also a valuable option in intermittent hemodialysis.

[Cholesterol embolism syndrome: a rare, but severe complication in patients with atherosclerosis]. / Cholesterinembolie-Syndrom: eine seltene, aber schwerwiegende Komplikation bei Atherosklerose.

Cholesterol embolization is a serious complication of atherosclerosis. Mainly, vascular manipulations during endovascular procedures or vascular surgery can release cholesterol crystals from atheromatous plaques. About 20 % are spontaneous emboli without precipitating event. The cholesterol crystals are distributed by the blood stream, occlude small arteries and induce inflammation. Typically, 2 to 6 weeks after a vascular procedure renal failure and characteristic cutaneous signs develop. Livedo reticularis and blue toes, although classic symptoms, are not pathognomonic and may be even absent. Vasculitis is an important differential diagnosis. Diagnosis can only be proven by skin, muscle or kidney biopsy. Alternatively, fundoscopy can show retinal cholesterol emboli. Therapy is mostly limited to symptomatic measures. Corticosteroids have no proven efficacy and may be harmful. Statins should be given to all patients due to their plaque stabilizing and anti-inflammatory properties. Randomized clinical trials are lacking in this field. Prognosis is limited. About 30-55 % patients with renal involvement need renal replacement therapy. Mortality is high with 15-30 % of patients dying during the first year.

Role of contact system activation in hemodialyzer-induced thrombogenicity.

BACKGROUND: The contact system is generally believed to be the main trigger of the coagulation cascade during extracorporeal circulation. However, the extent of contact activation, its role for intradialytic thrombin generation as well as the influence of different dialyzer membranes have not been well established. METHODS: In a novel full-scale ex vivo recirculation dialysis model, we investigated the thrombogenicity of three widely used hemodialyzers (Cuprophan Renak RA15-U, Polysulfone F6HPS and AN69XT Nephral 200). The activation of the contact system was evaluated using a newly developed ELISA for factor XIIa-C1-inhibitor complexes. Additionally, we determined free FXIIa (ELISA), thrombin-antithrombin (TAT) complexes, platelet factor 4 (PF4), complement activation (C5a), granulocyte elastase and blood cell counts. The findings in blood from normal volunteers were compared with factor XII-deficient blood. RESULTS: With normal blood AN69 exhibited the highest thrombogenicity in comparison to Cuprophan and Polysulfone, as assessed by TAT generation and platelet consumption. AN69 caused a rapid increase of the FXIIa-C1-inhibitor complexes and of free FXIIa. Despite significant TAT generation with Cuprophan and Polysulfone free FXIIa remained unchanged and the FXIIa-C1-inhibitor complexes stayed below the detection limit. With factor XII-deficient blood Polysulfone exhibited the same TAT generation, whereas the thrombogenicity of AN69 was greatly reduced. CONCLUSIONS: Our data challenge the common assumption that activation of the contact system with generation of FXIIa is the main trigger for coagulation and thrombus formation in hemodialysis. Only the negatively charged AN69 membrane with enhanced thrombogenicity strongly induced contact activation.

Glutardialdehyde induced fluorescence technique (GIFT): a new method for the imaging of platelet adhesion on biomaterials.

One of the major limitations of biomaterials used in medicine is the adhesion and subsequent activation of platelets upon contact with blood. The development of new or modified materials necessitates adequate methods for the detection and quantification of platelet/material interactions. These interactions are commonly investigated by means of scanning electron microscopy (SEM), radioisotope and immunological techniques, or by quantification of released platelet contents. Given the lack of a simple, rapid, and inexpensive assay, we developed a novel method for the accurate assessment of platelet adhesion after contact with foreign surfaces, which enables quantitative measurements as well as imaging of the platelet shape change, and which omits conventional or immunological staining and time-consuming preparative steps. The glutardialdehyde induced fluorescence technique (GIFT) uses the epifluorescence of glutardialdehyde-fixed platelets detected by fluorescence microscopy and is suitable for opaque and transparent materials. Combined with computer-aided image analysis, numbers of adherent platelets, platelet-covered surface, and average platelet spread area can be determined as markers of surface thrombogenicity. To validate the technique, four materials of different thrombogenicity [polypropylene (PP), poly(D,L-lactide) (PDLLA), 2-hydroxyethyl-methacrylate-grafted PDLLA (PDLLA-HEMA), and heparin-coupled PDLLA-HEMA] were investigated by GIFT and SEM. We found concordant results with SEM and GIFT with the following ranking of thrombogenicity: PP > PDLLA > PDLLA-HEMA > or = PDLLA-HEMA-heparin. GIFT significantly discriminated between the investigated materials. The surface modifications led to improved thromboresistance with reduced platelet adhesion and shape change. The main advantages of GIFT as compared with SEM are: no vacuum-drying or dehydration, less time-consuming procedure, fixation and fluorescence "staining" in one step, and suitability for computer-aided image analysis allowing quantitative assessment of platelet adhesion as well as imaging of the platelet shape change with high-contrast images. In conclusion, GIFT is a valid, rapid, and simple method for the quantitative determination of platelet/material interactions intended for the evaluation of thrombogenicity of biomaterials surfaces.