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Biomedical subjects

R Kuhlen

Publications and source records attributed to R Kuhlen.

At least 19 recordsLinked to original sources

[Abdominal compartment syndrome: significance, diagnosis and treatment].

A pathological increase of intraabdominal pressure (IAP) is frequently observed in severely ill patients suffering from surgical diseases. This may lead to the abdominal compartment syndrome (ACS) which is characterized by an IAP >20 mmHg (>2.67 kPa) and failure of one or more organ systems. The mortality of ACS exceeds 60%. Knowledge concerning the sequelae of ACS is abundant, however, measurement of IAP is not routinely performed even if patients present with corresponding risk factors. This is probably due to a variable incidence of ACS and scepticism regarding the results of bladder pressure measurement. However, measurement of IAP can now be performed semi-automatically, continuously and in a standardized fashion. The therapy of ACS, i.e. decompression laparotomy and laparostomy, is undisputed. Since a heterogeneous group of patients can be affected, monitoring of IAP is indicated in patients needing intensive care. A consistent registration of IAP will improve knowledge and guidelines regarding the therapy of a pathologically increased IAP. Nevertheless, patients in whom ACS is suspected should be decompressed as soon as possible.

Abdomen↗

Role of extracorporeal lung assist in the treatment of acute respiratory failure.

For patients with most severe acute respiratory distress syndrome (ARDS) conservative treatment with lung protective ventilation is often not sufficient to prevent life-threatening hypoxemia and additional strategies are necessary. Extracorporeal lung assist (ECLA) or extracorporeal membrane oxygenation (ECMO) using capillary membrane oxygenators can provide sufficient gas exchange and lung rest. In 2 randomized trials mortality was unchanged for ECMO. Today an technically enhanced ECMO is used for most severe ARDS using clinical algorithm and different case studies demonstrated a survival rate about 56%. Today miniaturized ECMO with optimized blood pumps and oxygenators are available and could enhance safety and clinical management. Another approach is an arterio-venous pumpless interventional lung assist (ILA) with a low resistance oxygenator. Advantages seem a simplified clinical management and less blood trauma. At present new devices are developed for chronic respiratory failure or bridge to lung transplant. Oxygenators with even less flow resistance could be implanted paracorporeal using the right ventricle as driving force. An intravascular oxygenator has been developed using the combination of a miniaturized blood pump and an oxygenator for implantation in the vena cava. Well designed clinical trials are necessary to demonstrate a clinical benefit for these experimental devices.

Acute Disease↗

Life-threatening postoperative blood loss in a Jehovah's Witness, treated with high-dose erythropoietin.

Six hours after an uncomplicated extended resection of ovarian cancer, postoperative arterial bleeding led to life-threatening blood loss in a 44-yr-old Jehovah's Witness who refused blood transfusion. Haemoglobin (Hb) decreased from 2.5 g dl(-1) directly after the emergency laparotomy, followed by a 10 h immeasurable period (below detectable minimum value of the analyser), to a measurable minimum of 1.5 g dl(-1) after 20 h. Haematopoiesis was induced by high-dose i.v. erythropoietin therapy (600 IU kg(-1)) and continued on days 3, 6, 8, 10 and 13. Iron, folic acid and vitamins were given as supplements. The patient needed ventilatory assistance for 18 days and some inotropic support. Complications included increases in pancreatic enzymes and liver enzymes, jaundice and skin necrosis at the fingertips and toes. Myopathy led to transient tetraparesis. Haemoglobin rose from 1.5 to 3.4 g dl(-1) (day 10) and the patient was discharged from the intensive care unit with haemoglobin 6.5 g dl(-1) on day 24. She made a full recovery and is still free of cancer in remission.

Adult↗

Successful use of recombinant factor VIIa in a patient with intractable bleeding during extracorporeal membrane oxygenation.

Bleeding is still the most common complication during extracorporeal membrane oxygenation (ECMO) for temporary cardio-circulatory support. We present a case of a young man suffering from intractable hemorrhage during ECMO support, who was pre-treated with glycoprotein IIb/IIIa receptor antagonist Tirofiban due to a suspicion of myocardial ischemia. After failure of conventional hemostatic means, hemostasis was achieved by the donation of recombinant Factor VIIa (rFVIIa). Aspects of bleeding control during extracorporeal circulatory support, the use of Tirofiban and rFVIIa are discussed.

Adolescent↗

Effect of hirudin versus heparin on hemocompatibility of blood contacting biomaterials: an in vitro study.

Hirudin serves as an alternative anticoagulant for extracorporeal blood circulation. Comparing anticoagulation with hirudin (2.5 or 5.0 microg/mL) and heparin (2.0 or 4.0 IU/mL) human blood was circulated in a modified 'Chandler System' using PVC-tubes for 2 hours at 37 degrees C. Activation of coagulation (thrombin-antithrombin III-complex, prothrombin fragment 1+2 and D-Dimer), platelet (platelet factor 4 - PF4) and complement systems was analyzed. Both heparin concentrations and 5.0 microg/dL hirudin led to as significantly less activated plasmatic coagulation as 2.5 microg/dL hirudin. Decreased levels of PF4 and anaphylatoxin C5a (p<0.05) as well as terminal complement complex demonstrated improved hemocompatibility after anticoagulation with heparin in contrast to hirudin. Because initial coagulation cascade, platelet activation and complement activation is less influenced by hirudin than by heparin, hemocompatibility is more dependent on the characteristics of the biomaterials used. This predestines hirudin as anticoagulant for in vitro studies analyzing hemocompatibility of biomaterials or surface modifications.

Analysis of Variance↗

Cardiopulmonary effects of iloprost in experimental acute lung injury.

Iloprost, a prostacyclin analogue with a prolonged plasma half-life has beneficial effects in chronic pulmonary hypertension, whereas the effects in acute lung injury (ALI) are unknown. The present study was performed to evaluate the cardiopulmonary effects of iloprost in experimental ALI. ALI was induced in 18 pigs by repeated lung lavage. Animals were randomised to controls, i.v. or inhaled iloprost for 15 min. Haemodynamics, gas exchange and ventilation-perfusion distribution were measured at the end of iloprost application and after 1 and 2 h. As a short-term effect, both i.v. and inhaled iloprost significantly decreased pulmonary artery pressure without major effects on gas exchange or systemic haemodynamics. After 1 and 2 h, a reduction of pulmonary hypertension was no longer present. As a long-term effect, inhaled, but not i.v., iloprost decreased pulmonary shunt and significantly improved gas exchange after 1 and 2 h. In conclusion, the single application of iloprost revealed short-term pulmonary vasodilation without other major cardiopulmonary effects. However, inhaled iloprost improved gas exchange due to a decrease of pulmonary shunt as a long-term effect, possibly as a result of a reduction of lung oedema formation.

Acute Disease↗

Artificial lung and extracorporeal gas exchange.

Over the last years, several observational studies have suggested that extracorporeal lung assist (ECLA) may be an important contribution to clinical algorithms for the treatment of most severe acute respiratory distress syndrome (ARDS). Today ECLA is used only as a rescue therapy in life threatening gas exchange disorders if maximal conventional therapy fails to prevent from hypoxemia. With subsequent reduction of complications and improvement of biocompability, extracorporeal membrane oxygentation (ECMO) indications may be extendend to treat patients earlier and not only in rescue situations along the original idea to buy the lung some time to heal by avoiding further ventilator associated lung injury. Veno-venous ECMO therapy at present is an important therapeutic option in severe ARDS with persisiting life threatening gas exchange disorder as a rescue therapy. The development of smaller, less complex and more secure ECMO or pumpless veno-arterial ECLA systems has the potential to perform controlled studies of its use in ARDS and potentially expand indications.

Animals↗

[Extracorporeal membrane oxygenation by acute respiratory distress syndrome].

After various observational studies demonstrated a benefit of extracorporeal membrane oxygenation (ECMO) in the therapy of severe acute respiratory distress syndrome (ARDS), ECMO now represents an important contribution for ARDS therapy using clinical algorithms despite a lack of positive controlled studies. In specialized centers patients with severe ARDS and imminent hypoxia despite intensive conventional therapy, are treated with ECMO using blood pumps and artificial membrane lungs (oxygenators) for extracorporeal lung assist. The development of new surface modifications, optimized oxygenators and miniaturized blood pumps should increase hemocompatibility and lead to simplified treatment as well as less complications. New oxygenators with significantly decreased blood resistance allow the clinical application of pumpless arteriovenous extracorporeal lung assist (ECLA). After these new developments indications for ECMO could be extended from use not only as ultimate ratio but to less severe ARDS to enable lung protective, less invasive mechanical ventilation.

Anticoagulants↗

[Treatment of acute respiratory distress syndrome in a treatment center. Success is dependent on risk factors].

SUBJECT: Mortality rates remain high for the acute respiratory distress syndrome (ARDS) despite standardised treatment algorithms. Little is known about prognostic factors and exclusion criteria for advanced treatment including extracorporeal membrane oxygenation (ECMO). METHODS: In an observational study design a cohort of 93 patients with severe ARDS admitted to a referral centre were analysed according to ventilatory and vital parameters. RESULTS: Overall survival rate was 70% and in patients who received ECMO treatment it was 67%. In patients exhibiting relevant co-morbidity the odds ratio for fatal outcome increased to 4.7 (95% CI: 3.3-24.9), and patients with multiple organ failure had a 7.5-fold increase (95% CI: 2.3-25.2) for risk of death. Survivors demonstrated a more pronounced improvement in oxygenation ( p<0.05) and CO(2) removal ( p<0.05) than non-survivors. CONCLUSIONS: Advanced treatment of ARDS including ECMO represents a therapeutic option if none of the currently considered contraindications are present. An improvement in gas exchange parameters, but not a defined value per se may be useful as a prognostic factor for favourable outcome.

Adult↗

[Aerosolized and intravenous prostacyclin during one-lung ventilation. Hemodynamic and pulmonary effects].

BACKGROUND: One-lung ventilation is frequently used in thoracic surgery. However, hypoxic pulmonary vasoconstriction of the atelectatic lung may produce pulmonary hypertension. The objective of the present study was to compare the acute effects of intravenous versus aerosolized prostacyclin (PGI(2)) on pulmonary and systemic circulation. METHODS: PGI(2) was administered in 11 anesthetized and unilaterally ventilated pigs by infusion (5, 10, and 20 ng/kg body weight/min) and by inhalation (4, 8, and 16 ng/kg body weight/min) in a cross-over design. RESULTS: Infusion of PGI(2) reduced both pulmonary (PVR) and systemic vascular resistance (SVR). Due to a concomitant increase in cardiac index (CI) mean arterial (MAP) and pulmonary artery pressures (MPAP) did not change significantly. In contrast, aerosolized PGI(2) produced a significant decrease in PVR (-21.4 to -32.8%) and MPAP (-12.0 to -17.8%) without affecting SVR, MAP, and CI. Arterial oxygenation tension (p(a)O(2)) was not affected. CONCLUSION: During one-lung ventilation only aerosolized prostacyclin produced a selective pulmonary vasodilation.

Administration, Inhalation↗

["Meet the AIX-PERTs." Emergency medical care at the beginning of the medical reform curriculum in Aachen].

BACKGROUND: Extensive knowledge and skills in the basics of emergency medical care are of paramount importance for every physician and should therefore be an integral part of medical education. METHODS: Regulations for medical licensure in Germany were revised by the administrative authorities in 2002 and as a consequence the Medical Faculty of the University of Aachen (Germany) decided to start the Medical Reform Curriculum Aachen. A multidisciplinary, problem-oriented and organ-related approach to medical education replaces the classical discrimination between basic and clinical sciences. RESULTS: With AIX-PERT (AIX-la-Chapelle Program for Emergency medical care and Resuscitation Training), a program consisting of problem-based learning sessions was developed for introduction to the first year students. Defined teaching objectives in emergency medicine are now incorporated in undergraduate medical education. CONCLUSION: The extremely positive evaluation of the new approach encouraged us to promote AIX-PERT further. In the future the effects of success of this approach will be assessed by longitudinal studies of skills and knowledge during the continuing curriculum.

Cardiopulmonary Resuscitation↗

[Requirements for the use of automated external defibrillators in German hospitals].

With an incidence of 130,000 per year, sudden cardiac death is one of the most frequent causes of death in Germany. Each day 350 patients die from cardiac arrest. Survival depends essentially on the time delay before professional help arrives and sufficient resuscitation measures have been started. At present, survival of sudden cardiac death is reported to be in the range of 5-8%. In preclinical conditions, many studies have already shown a successful use of automated external defibrillators (AED) by first responders even if they are lay persons. Even in large hospitals with maximum care facilities, delays before beginning resuscitation measures can occur which results in a dramatic reduction of the survival rate. Therefore, it seems reasonable to use AED in large hospitals. For implementation, training programmes and a nationally standardized documentation of resuscitation events should be promoted.

Cardiopulmonary Resuscitation↗

[Venous thromboembolism prophylaxis].

Venous thromboembolism is a common and frequent complication of hospitalized patients. Some venous thromboembolisms may be subclinical, while others present as symptomatic deep vein thrombosis and/or pulmonary embolism. Venous thromboembolism and pulmonary embolism contribute significantly to inhospital morbidity and mortality. The risk of venous thromboembolism is aggravated by dispositional and/or expositional risk factors. In patients at intermediate or high risk of venous thromboembolism, additional pharmacological thromboembolism prophylaxis becomes mandatory.

Anesthesia↗