Biomedical subjects

R Rossaint

Publications and source records attributed to R Rossaint.

At least 37 records · Page 2Linked to original sources

PubMed2005

[Hotline 2: heating capabilities of a coaxial fluid warming system at low and moderate flow rates].

OBJECTIVE: The aim of this study was to compare the effects of two coaxial fluid warming systems with their heating capabilities. METHODS: The heating capabilities of two coaxial fluid warming systems and their capabilities to warm fluids at 20 +/- 0.5 degrees C (20 degrees C room temperature) was measured: 1) Hotline 1 Fluid Warmer, 2) Hotline(R) 1 Fluid Warmer. Final temperatures were measured at different infusion rates (10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 200, 400, 800, 1000 ml/h and at maximal flow rates (Vmax)), at the distal end of the disposable tubing. Statistical analysis was performed using a computer based program (NCSS). Differences between the groups were analysed using the Two-Way-ANOVA. Significance was defined at a p < 0.05. RESULTS: At flow rates between 10 - 1000 ml/h, infusion temperatures of > 36 degrees C were attained by both devices in a reliable manner. Compared to Hotline 1, Hotline 2 attained higher final temperatures of between 1.2 - 3.8 % (p < 0.01). Hotline 1 was measured to have higher Vmax (+ 3.6 %) compared to Hotline 2 (p < 0.01). However, the mean final temperature at Vmax of Hotline 2 was increased by 6.5 % (p < 0.01). The time needed to warm target temperature to 40 - 41 degrees C took between 9 to 12 minutes (flow rate 10 ml/h and Vmax respectively) when using Hotline 1 and 3 to 4 minutes when using Hotline 2. CONCLUSION: Compared to its predecessor, the Hotline 2 performance is a valuable improvement with respect to heating capacity and clinical handling.

Hypothermia↗

PubMed2005

[Characteristics of repeated emergency physician use].

OBJECTIVE: Repeated use of emergency physicians might result in excessive costs and has discouraging effects on emergency department staff. To our knowledge, no data are available on the characteristic of repeated use of emergency physicians (EP) in the German emergency medical services. Accordingly, this retrospective survey focused on emergency cases on-the-scene, which necessitated EP intervention. METHODS: Following data from the local EMS computerised database (Medlinq, EASY, Hamburg, Germany) were retrospectively analysed for the period from January to December of 2002: total number of EP interventions, person who engaged the emergency call, number of repeat EP-users with two to three calls, number of frequent EP-users with more than three calls, their sex, age, NACA. Probably inappropriate repeat users were defined as patients with no apparent underlying distress on-the-scene, lack of preclinical findings which could explain the symptoms initially mentioned, and refuse of hospital referral by the patient. The rate of repeated inappropriate EP use was defined as the ratio of the number of repeated inappropriate use over the total number of EP-engagements in the year 2002. RESULTS: 6064 EP interventions were analysed. The rate of the repeated use was 15.5 % (939/6064) including 3.6 % (218/6064) frequent users. The main medical causes (80 %) of repeated EP use were cardiovascular, neurological, respiratory, and psychiatric. The rate of repeated inappropriate EP use was 0.2 % (11/6064). CONCLUSION: The rate of repeated inappropriate EP use in this middle sized town was low. More than four fifths of all repeated calls were for cardiovascular, respiratory, neurological, and psychiatric distress.

Adult↗

PubMed2005

Xenon anaesthesia may preserve cardiovascular function in patients with heart failure.

BACKGROUND: The hypothesis that xenon anaesthesia provided haemodynamic stability was tested in patients with heart failure in a prospective, randomized, single-blind design. METHODS: Twenty-six patients scheduled for implantation of a cardioverter-defibrillator (ICD) received xenon 60-65% in oxygen (xenon group, n = 12) or propofol 3 mg/kg/h (propofol group, n = 14), both combined with remifentanil 0.2 microg/kg/min. After induction of anaesthesia with etomidate and remifentanil, heart rate (HR), mean arterial pressure (MAP) and left ventricular ejection fraction (LVEF) were recorded. After 60 min of propofol or xenon anaesthesia, the same parameters were recorded. RESULTS: While HR decreased in both groups, MAP was unchanged with xenon (73 vs. 76 mmHg) and decreased with propofol (from 78 to 64 mmHg, P < 0.02). LVEF was stable in both groups [32% vs. 37%, xenon (NS), and 30% vs. 34%, propofol (NS)]. Preload, as measured by end-diastolic volume (EDV), did not change (66 vs. 63 ml with xenon; 79 vs. 81 ml with propofol, both NS). Afterload, as determined by end-systolic pressure-volume product (ESPV), decreased with propofol (6760 vs. 4920 ml mmHg) but not with xenon (4060 vs. 3780 ml mmHg, P < 0.01 between groups). CONCLUSION: With propofol, MAP is reduced and LVEF is not increased in spite of reduced afterload. In contrast, MAP and LVEF are maintained with xenon.

Aged↗

PubMed2005

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↗

PubMed2005

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↗

PubMed2005

Effects of a single dose of ketamine on duodenal motility activity in pigs.

In order to investigate the effects of a single dose of ketamine on duodenal motility, the present study focused on the electric impedance technique. Five pigs (32 to 40 kg, CVC group) were instrumented with a central venous catheter 1 d before measurements. The next day, general anesthesia was started and maintained via central venous catheter by propofol and fentanyl. In contrast, the pigs of the KETA group (n = 5) received ketamine intramuscularly prior to the induction of anesthesia by the injection of propofol-fentanyl via an ear vein. An intraluminal impedance catheter was manually introduced into the proximal duodenum. Measurements were recorded for 4 h. The KETA group showed a median duration of phase II that was shortened by 35%, while phase I was prolonged by 73% (P < 0.05). In conclusion, when gastrointestinal motility has to be investigated, the effects of a single dose of ketamine, even for premedication, should be taken into consideration.

Anesthetics, Dissociative↗

PubMed2005

Effects of propofol and fentanyl on duodenal motility activity in pigs.

To investigate the effects of propofol and fentanyl on the postprandial duodenal motility the intraluminal impedance technique was used. Six pigs were instrumented with a central venous catheter, a percutaneous enterogastrostomy (PEG), and an impedance catheter, which was introduced via the PEG into the duodenum through endoscopy. Over the following 3 d, duodenal motility was measured for 8-hour periods. Measurements were taken on each subject under 3 different sets of conditions: in the conscious unrestrained pig, during propofol sedation, and during sedation with propofol-fentanyl. Both, after morning feeding and during gastric nutrition via the PEG, duodenal feeding patterns and duodenal phase II of the migrating motor cycle were shortened during propofol and propofol-fentanyl sedation. In contrast, the duration of phase I was prolonged by propofol and propofol-fentanyl. In conclusion, either propofol or propofolfentanyl sedation shortens duodenal feeding patterns, as well as phase II of the migrating motor cycle.

Animals↗

PubMed2004

Randomized controlled trial of the haemodynamic and recovery effects of xenon or propofol anaesthesia.

BACKGROUND: There is limited clinical experience with xenon in a large number of patients. We present intra- and postoperative haemodynamic and recovery data comparing xenon and total intravenous anaesthesia with propofol. METHODS: A total of 160 patients aged 18-60 years (ASA I and II) undergoing elective surgery took part in this prospective non-blinded randomized controlled trial. After local ethics committee approval and written informed consent, patients were allocated randomly to either the xenon or the propofol group. Anaesthesia was induced with propofol and remifentanil and was maintained with xenon at 60% (minimal alveolar concentration 0.95) or with propofol 0.1-0.12 mg kg(-1) min(-1). Remifentanil was titrated to clinical need in both groups. RESULTS: The two study groups were comparable with respect to age, weight, height, gender and ASA classification. Baseline in heart rate and systolic arterial pressure (SAP) were comparable in both groups. Following induction, SAP initially decreased but returned to baseline values over 15 min in the xenon group and differed significantly from the propofol group. Heart rate decreased significantly only in the xenon group and remained at stable values. Occurrence and duration of hypertension, hypotension and bradycardia showed no significant difference between groups. Patient recovery time in the post-anaesthetic care unit and recovery from anaesthesia was similar in the two groups. CONCLUSIONS: After induction the xenon/opioid regimen maintains systolic blood pressure at baseline levels and a low heart rate. No differences between groups were found in haemodynamic stability during anaesthesia. Recovery from xenon anaesthesia was similar to that observed in the propofol group.

Adolescent↗

PubMed2004

Effects of xenon anaesthesia on intestinal oxygenation in acutely instrumented pigs.

BACKGROUND: Xenon is a narcotic gas that might be able to replace volatile anaesthetics or nitrous oxide due to its favourable pharmacological properties, such as providing haemodynamic stability. Intestinal oxygenation is affected by most volatile anaesthetics as a result of cardiodepressive effects. Reducing oxygenation of the gut might be a factor leading to perioperative organ dysfunction. This animal study was designed to assess the effects of xenon on intestinal oxygenation. METHODS: After ethical approval, 24 anaesthetized, acutely instrumented pigs were randomly assigned to three groups: nine animals received xenon anaesthesia with inspiratory concentrations of 0, 20, 50 and 65% in addition to their basic i.v. anaesthesia, nine animals served as a study control group, and five animals were used to assess model stability. Measurement of systemic and regional haemodynamic and oxygenation parameters was made 30 min after changing the xenon concentration. RESULTS: Xenon elicited dose-dependent systemic haemodynamic changes: heart rate and cardiac output decreased by 30%, while mean arterial pressure was stable. Superior mesenteric artery blood flow was lower in the xenon group. Vascular resistance of the superior mesenteric artery increased. The small intestinal oxygen supply decreased with increasing xenon concentration; the mucosal tissue oxygen partial pressure decreased but did not reach hypoxic (<5 mm Hg) values. Serosal tissue oxygen partial pressure was maintained. CONCLUSIONS: Xenon, in addition to basic i.v. anaesthesia, elicited a decrease in cardiac output and maintained mean arterial pressure. Intestinal oxygenation was maintained, although regional macrohaemodynamic perfusion decreased. Xenon does not impair intestinal oxygenation under physiological conditions.

Anesthetics, Combined↗

PubMed2004

Prediction of fluid responsiveness in patients during cardiac surgery.

BACKGROUND: Left ventricular stroke volume variation (SVV) has been shown to be a predictor of fluid responsiveness in various subsets of patients. However, the accuracy and reliability of SVV are unproven in patients ventilated with low tidal volumes. METHODS: Fourteen patients were studied immediately after coronary artery bypass grafting (CABG). All patients were mechanically ventilated in pressure-controlled mode [tidal volume 7.5 (1.2) ml kg(-1)]. In addition to standard haemodynamic monitoring, SVV was assessed by arterial pulse contour analysis. Left ventricular end-diastolic area index (LVEDAI) was determined by transoesophageal echocardiography. A transpulmonary thermodilution technique was used for measurement of cardiac index (CI), stroke volume index (SVI) and intrathoracic blood volume index (ITBI). All variables were assessed before and after a volume shift induced by tilting the patients from the anti-Trendelenburg (30 degrees head up) to the Trendelenburg position (30 degrees head down). RESULTS: After the change in the Trendelenburg position, SVV decreased significantly, while CI, SVI, ITBI, LVEDAI, central venous pressure (CVP) and pulmonary artery occlusion pressure (PAOP) increased significantly. Changes in SVI were significantly correlated to changes in SVV (r=0.70; P<0.0001) and to changes in LVEDAI, ITBI, CVP and PAOP. Only prechallenge values of SVV were predictive of changes in SVI after change from the anti-Trendelenburg to the Trendelenburg position. CONCLUSIONS: In patients after CABG surgery who were ventilated with low tidal volumes, SVV enabled prediction of fluid responsiveness and assessment of the haemodynamic effects of volume loading.

Aged↗

PubMed2004

Minimum alveolar concentration (MAC) of xenon in intubated swine.

BACKGROUND: The minimum alveolar concentration (MAC) is a traditional index of the hypnotic potency of an inhalational anaesthetic. To investigate the anaesthetic as well as the unwanted effects of xenon (Xe) in a swine model, it is useful to know MAC(Xe). METHODS: The study was performed using ten swine (weight 27.8-35.4 kg) anaesthetized with halothane and Xe 0, 15, 30, 40, 50 and 65% in oxygen. With each Xe concentration, various concentrations of halothane were administered in a step-by-step design. For each combination, a supramaximal pain stimulus (claw clamp) was applied and the appearance of a withdrawal reaction was recorded. The MAC(Xe) with halothane was calculated using a logistic regression model. RESULTS: During stable ventilation, haemodynamics and temperature, MAC(Xe) value was determined as 119 vol. % (95% confidence limits 103-135). CONCLUSION: MAC(Xe) in swine was calculated by extrapolation of a logistic regression model. Its theoretical value is 119 vol. %.

Anesthesia, Closed-Circuit↗

PubMed2004

[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↗

PubMed2004

[Cuff pressure monitoring and regulation in adults].

OBJECTIVES: In adults the use of cuffed endotracheal tubes is the standard technique. Nitrous oxide increases the cuff pressure secondary to diffusion through the cuff membrane. The aim of the study was to verify a newly designed cuff pressure regulating device and comparison of postoperative complications. METHODS: In a prospective, randomized, open trial the cuff pressure and the incidence of postoperative complications (e.g., hoarseness, coughing and pain while swallowing) were measured using the newly designed automatic pressure monitoring and regulating device Cuff Pressure Control (Tracoe) and a conventional handheld manometer. A total of 40 patients were assigned to the automatic group with a goal of 25.5 cmH(2)O and 40 patients to the conventional group where the pressures were kept between 20 cmH(2)0 and 40 cmH(2)0 with intermittent measurements and manual pressure release. RESULTS: The automatic device reliably maintained the pressure at the chosen constant level within +/-2 cmH(2)O. In the control group increases in cuff pressure to 40 cmH(2)O were common. The incidence of postoperative complications in both groups was not significantly different. CONCLUSIONS: In conclusion our data demonstrate that the automatic cuff pressure and regulation device was useful and reliable in an adult population of intubated patients in the studied pressure range.

Adult↗

PubMed2004

[Blood gas analysis].

Blood gas analysis provides valuable information about both the extracellular acid-base status and gas exchange. A blood gas analyzer measures pH, partial pressure of oxygen(pO(2)), partial pressure of carbon dioxide (pCO(2)), O(2) saturation, and hemoglobin concentration. A number of calculated parameters can be derived from these direct measurements such as bicarbonate concentration, base excess, oxygen content, etc. This contribution introduces the basic technical aspects of a blood gas analyzer and then describes some of the parameters that facilitate evaluation of the acid-base status and the oxygenation status of the blood. Finally, proper sampling and handling of blood gas samples is addressed.

Blood Gas Analysis↗

PubMed2004

[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↗

PubMed2004

["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↗

PubMed2004

[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↗

PubMed2004

[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↗