T. P. Weber

Limited upper thoracic epidural block and splanchnic perfusion in dogs.

UNLABELLED Epidural blockade leads to a sympathetic block in affected segments and an increase of sympathetic out-flow from various unblocked segments. A limited upper thoracic epidural block (LUTEB) is used during coronary artery surgery affecting the cardiac sympathetic fibers cephalad to the fifth thoracic segment. This block does not extend to the sympathetic fibers innervating the gastrointestinal organs. A LUTEB may lead to an increase of sympathetic activity in the unaffected splanchnic sympathetic segments and the decrease in splanchnic blood flow may contribute to gastrointestinal ischemia after cardiac surgery. We tested the hypothesis that a LUTEB decreases splanchnic perfusion in anesthetized dogs. Thirteen dogs were chronically instrumented with aortic and left atrial catheters, which were used for pressure measurement, as well as injection and withdrawal of reference samples. Thoracic epidural catheters were placed under general anesthesia the day before the experiment. Splanchnic blood flow was determined by using colored microspheres. Induction of a LUTEB did not change general hemodynamics in awake dogs. Propofol anesthesia induced an increase in heart rate that was abolished after LUTEB. LUTEB also decreased mean arterial pressure during propofol anesthesia. We conclude that thoracic epidural anesthesia had no effect on splanchnic blood flow. In propofol anesthetized animals, liver blood flow was increased compared with awake animals; however, it did not change after induction of LUTEB. IMPLICATIONS A sympathetic block in certain segments leads to increased sympathetic output in unblocked segments. For an upper thoracic epidural block, this might lead to impaired splanchnic perfusion. In awake and propofol-anesthetized, chronically instrumented dogs, however, a limited upper thoracic epidural blockade had no compromising effect on gastrointestinal perfusion.

[Chest compression quality : Can feedback technology help?].

BACKGROUND The outcome of cardiopulmonary resuscitation (CPR) depends on the quality of chest compressions. Current European Resuscitation Council (ERC) guidelines promote the development of feedback systems. However, no studies presenting satisfactory results of feedback use have been published. METHODS A total of 60 patients with cardiac arrest (> or =18 years of age) received resuscitation attempts using an automated external defibrillator (AED) with real-time feedback by the ambulance service of the City of Münster. The frequency of chest compressions, no-flow time (NFT) and depth of chest compressions were analyzed for the first three cycles of CPR and compared to the ERC guidelines 2005. RESULTS Chest compression frequency did not differ significantly from the ideal as set out in the guidelines. Analysis of NFTs showed significantly longer NFT for the first cycle but NFT for the second and third cycles did not differ significantly from the ideal. The target depth of 4-5 cm was achieved in 80% of all chest compressions in the first 3 cycles. CONCLUSION With the AED real-time feedback technology used in this study standardized performance of chest compressions could be maintained in a professional ambulance service. Implementation of a feedback system requires training of ambulance staff.

Beeinflussen soziodemografische Faktoren Notarzteinsätze

BACKGROUND Demographic development and changes in healthcare utilization have led to a rising number of calls for emergency services. In Germany life-threatening situations are responded by physician-staffed ambulances in a 2-tier system whereas paramedic-staffed ambulances are dispatched in non-life-threatening emergencies. A nationwide protocol guides dispatchers in triage decisions. In the years 1999 to 2009 a continuous rise in the number of calls for a physician-staffed ambulance in Münster was recorded. The degree of healthcare utilization according to socioeconomic status and age structure was retrospectively examined. METHODS For the year 2006 all emergency calls in the City of Münster responded to by physician-staffed ambulances were analyzed. Each call was assigned to 1 of the 45 urban districts. The local incidence of emergency calls (calls/100 residents/year) was determined and compared to the socioeconomic status which was defined as the percentage of welfare and unemployment benefit recipients per district. Patient condition was assessed by the Munich National Advisory Committee for Aeronautics (M-NACA) score. This scoring system allows calls to be allocated to either life-threatening conditions or non-life-threatening conditions by objective vital parameters. The age structure of the emergency callers was also examined. RESULTS Urban districts with a low socioeconomic status showed a higher incidence of emergency calls requiring physician-staffed ambulance responses than districts with a high socioeconomic status. Measured by the M-NACA scoring system, the fraction of life-threatening emergencies among all calls proved to be equal to districts with a high socioeconomic status. A correlation between elderly patients and increasing numbers of life-threatening emergencies was found. CONCLUSIONS A low socioeconomic status of an urban district will result in more ambulance responses. However, the proportion of life-threatening emergencies is equal to districts with a high socioeconomic status. Thus, the greater need for physician-staffed ambulance responses matches clinical needs and legitimates current resource use in a 2-tier ambulance system. Indications for the abuse of physician-staffed ambulances were not found. Considering an aging population the number of emergency calls will rise in the future.

Reduced serine–16 and threonine–17phospholamban phosphorylation instunning of conscious dogs

AbstractObjectiveCardiac stunning is the consequence of a brief cardiac ischemia. The underlying mechanism is not completely understood.MethodsHere we induced cardiac transient ischemia in conscious instrumented dogs by means of an occluder in the left anterior descending coronary artery (LAD). Contractile performance, monitored by ultrasound crystals, was reduced during and after ischemia in the LAD area. For control in the same animals cardiac performance was measured in the area of left circumflex coronary artery (Ramus circumflexus, RCx). In the RCx area, no decline in contractility was noted. Tissue was obtained from stunned LAD area and from control areas (RCx).ResultsPhospholamban phosphorylation on both serine–16 and threonine–17 was reduced in LAD areas compared to RCx areas. Reduced phosphorylation of PLB is known to inhibit cardiac contractility. While phosphorylation of PLB was reduced, the activity of the appropriate protein phosphatases and protein kinases was not different between tissue obtained from LAD or RCx areas.ConclusionReduced formation of cAMP might underlie the contractile dysfunction in myocardial stunning.

Perivascular axillary brachial plexus block and patient positioning: the influence of a lateral, head-down position

The aim of this study was to examine the effect of a 20° Trendelenburg position on the blockade of nerves that exit the brachial plexus proximally in patients undergoing single‐injection axillary brachial plexus block. After a pilot study of eight cadavers suggested that a head‐down and lateral position would encourage the proximal spread of local anaesthetic, 72 patients undergoing elective surgery were divided into two equal groups: a Supine group and a Modified Position group (lateral position, 20° head‐down tilt). Patients were left in the allocated position for 30 min after an axillary block had been performed with alkalinised mepivacaine 1% 49.5 ml. Sensory and motor blockade evaluation showed that there was a significantly higher proportion of axillary nerve (76% vs. 0%, p < 0.001), thoracodorsal nerve (86% vs. 0%, p < 0.001) and subscapular nerve (89% vs. 0%, p < 0.001) blockade in the Modified Position group. Sensory block of the radial nerve was also improved by the modified position (100% vs. 86%, p < 0.05).

Oberarmkorrekturosteotomie bei einem Patienten mit McCune-Albright-Syndrom unter perivaskulärer axillärer Plexusanästhesie nach Weber

We report on a 20-year-old patient with McCune-Albright syndrome suffering from global respiratory insufficiency who required continuous mask ventilation and where intubation had to be avoided. Perivascular axillary anesthesia according to Weber was performed for a double corrective osteotomy of the humerus. During plexus anesthesia the patient was positioned on the non-anesthesized side in a 15 degrees Trendelenburg position. An extension of analgesia was observed up to the complete upper arm region. Using the modified positioning an extension of brachial plexus anesthesia is possible.ZusammenfassungBei einem 20-jährigen Patienten mit McCune-Albright-Syndrom und respiratorischer Globalinsuffizienz mit Dauermaskenbeatmung musste eine Intubationsnarkose vermieden werden. Zur operativen Korrektur einer schwergradigen Oberarmfehlstellung erfolgte eine perivaskuläre axilläre Plexusanästhesie nach Weber. Mit der Lagerung des Patienten auf die nichtbetroffene Seite und Kopftieflagerung von 15° (modifizierte Lagerungstechnik) konnte eine Ausbreitung der Analgesie bis auf die Oberarmregion erreicht werden.AbstractWe report on a 20-year-old patient with McCune-Albright syndrome suffering from global respiratory insufficiency who required continuous mask ventilation and where intubation had to be avoided. Perivascular axillary anesthesia according to Weber was performed for a double corrective osteotomy of the humerus. During plexus anesthesia the patient was positioned on the non-anesthesized side in a 15° Trendelenburg position. An extension of analgesia was observed up to the complete upper arm region. Using the modified positioning an extension of brachial plexus anesthesia is possible.

Beeinflussen soziodemografische Faktoren Notarzteinsätze?@@@Do sociodemographic factors influence emergency medical missions?: Analyse in der Stadt Münster@@@Analysis in the City of Münster

BACKGROUND Demographic development and changes in healthcare utilization have led to a rising number of calls for emergency services. In Germany life-threatening situations are responded by physician-staffed ambulances in a 2-tier system whereas paramedic-staffed ambulances are dispatched in non-life-threatening emergencies. A nationwide protocol guides dispatchers in triage decisions. In the years 1999 to 2009 a continuous rise in the number of calls for a physician-staffed ambulance in Münster was recorded. The degree of healthcare utilization according to socioeconomic status and age structure was retrospectively examined. METHODS For the year 2006 all emergency calls in the City of Münster responded to by physician-staffed ambulances were analyzed. Each call was assigned to 1 of the 45 urban districts. The local incidence of emergency calls (calls/100 residents/year) was determined and compared to the socioeconomic status which was defined as the percentage of welfare and unemployment benefit recipients per district. Patient condition was assessed by the Munich National Advisory Committee for Aeronautics (M-NACA) score. This scoring system allows calls to be allocated to either life-threatening conditions or non-life-threatening conditions by objective vital parameters. The age structure of the emergency callers was also examined. RESULTS Urban districts with a low socioeconomic status showed a higher incidence of emergency calls requiring physician-staffed ambulance responses than districts with a high socioeconomic status. Measured by the M-NACA scoring system, the fraction of life-threatening emergencies among all calls proved to be equal to districts with a high socioeconomic status. A correlation between elderly patients and increasing numbers of life-threatening emergencies was found. CONCLUSIONS A low socioeconomic status of an urban district will result in more ambulance responses. However, the proportion of life-threatening emergencies is equal to districts with a high socioeconomic status. Thus, the greater need for physician-staffed ambulance responses matches clinical needs and legitimates current resource use in a 2-tier ambulance system. Indications for the abuse of physician-staffed ambulances were not found. Considering an aging population the number of emergency calls will rise in the future.

Axillary plexus block according to Weber is more effective than Büttnerʼs method in supine position: A-435

Department of Anesthesiology and Intensive Care Medicine, University of Münster, Munster, Germany Background and Goal of Study: Using the axillary brachial plexus block (AP) according to Weber with lateral positioning combined with 20° Trendelenburg positioning it is possible to reach more proximal nerves (1) than with Büttner’s method in supine position (2). It is not clear whether the two methods are equally efficient. Therefore, in this prospective, randomized, single-blind study we compared the sensory and motoric quality, spread and time to obtain a complete block, tourniquet, frequency of supplemented nerve blocks and the need for general anaesthesia. Materials and Methods: After a positive vote of the local Ethics Committee 108 patients undergoing hand surgery were separated into 2 groups: B (Büttner) and W (Weber). The block was performed (using a nerve stimulator) with 45 mL mepivacaine 1% (MEPI1%) and NaHCO3 (1:10). The musculocutaneous nerve was separately blocked with 5 mL MEPI1%. Only in group W patients were positioned onto the anaesthetized side for 30 minutes according to Weber. Incomplete blocks were supplemented 30 min after the initial block. Results: A greater success rate of a complete sensory block was found in group W (88,9%* vs. 71,3%). Incomplete blocks were more successfully supplemented in group W (8,3%* vs. 19,4%). The need for general anaesthesia was lower in group W (2,8%* vs. 9,3%). Only in group W a complete sensory block of axillary nerve (NA) occurred (65,7%** vs. 0,0) and 21,3% vs. 13,9% of incomplete sensory block was found. Motor blocks of the NA (74,1%** vs. 0,0), of the thoracodorsal nerve (NT) in (64,8%** vs. 0,0), and the subscapular nerve (NS) (74,1%** vs. 0,0), occurred only in group W. Statistics: Chi-quadrat-test corrected by Yates (p 0.05; sign. *, p 0.001; sign. **). Conclusion: The axillary brachial plexus block according to Weber with positioning onto the anaesthetized side reduces the need for supplemented nerve blocks and the need for general anaesthesia, when compared to the method in supine position according to Büttner. References: 1 Orlowski O. Reg Anesth Pain Med 2004; Vol. 29: No. 5: Suppl. 2: 14. 2 Büttner J. Reg Anaesth 1988 Jan; 11: 7–11.

Oberarmkorrekturosteotomie bei einem Patienten mit McCune-Albright-Syndrom unter perivaskulärer axillärer Plexusanästhesie nach Weber@@@Corrective osteotomy of the humerus using perivascular axillary anesthesia according to Weber in a patient suffering from McCune-Albright syndrome

We report on a 20-year-old patient with McCune-Albright syndrome suffering from global respiratory insufficiency who required continuous mask ventilation and where intubation had to be avoided. Perivascular axillary anesthesia according to Weber was performed for a double corrective osteotomy of the humerus. During plexus anesthesia the patient was positioned on the non-anesthesized side in a 15 degrees Trendelenburg position. An extension of analgesia was observed up to the complete upper arm region. Using the modified positioning an extension of brachial plexus anesthesia is possible.ZusammenfassungBei einem 20-jährigen Patienten mit McCune-Albright-Syndrom und respiratorischer Globalinsuffizienz mit Dauermaskenbeatmung musste eine Intubationsnarkose vermieden werden. Zur operativen Korrektur einer schwergradigen Oberarmfehlstellung erfolgte eine perivaskuläre axilläre Plexusanästhesie nach Weber. Mit der Lagerung des Patienten auf die nichtbetroffene Seite und Kopftieflagerung von 15° (modifizierte Lagerungstechnik) konnte eine Ausbreitung der Analgesie bis auf die Oberarmregion erreicht werden.AbstractWe report on a 20-year-old patient with McCune-Albright syndrome suffering from global respiratory insufficiency who required continuous mask ventilation and where intubation had to be avoided. Perivascular axillary anesthesia according to Weber was performed for a double corrective osteotomy of the humerus. During plexus anesthesia the patient was positioned on the non-anesthesized side in a 15° Trendelenburg position. An extension of analgesia was observed up to the complete upper arm region. Using the modified positioning an extension of brachial plexus anesthesia is possible.

Recovery from myocardial stunning is faster with desflurane compared to propofol in chronically instrumented dogs

Volatile anesthetics exert a protective role in myocardial ischemia. An increase in sympathetic tone might exert deleterious effects on the ischemic myocardium. The use of the volatile anesthetic desflurane in myocardial ischemia is controversial because of its sympathetic activation. We compared propofol and desflurane on myocardial stunning in chronically instrumented dogs. Mongrel dogs (n = 8) were chronically instrumented for measurement of heart rate, left atrial, aortic, and left ventricular pressure, rate of rise of left ventricular pressure, and myocardial wall-thickening fraction (WTF). An occluder around the left anterior descending artery (LAD) allowed the induction of reversible LAD-ischemia. Two experiments were performed in a cross-over fashion on separate days: 1) Induction of 10 min of LAD-ischemia during desflurane anesthesia and 2) Induction of 10 min of LAD-ischemia during propofol anesthesia. Both anesthetics were discontinued immediately after completion of ischemia. WTF was measured at predetermined time points until complete recovery from ischemic dysfunction occurred. Both anesthetics caused a significant decrease of WTF in the LAD-perfused myocardium. LAD-ischemia led to a further significant decrease of LAD-WTF in both groups. During the first 3 h of reperfusion, WTF was significantly larger in the desflurane group. Mean arterial pressure and heart rate were greater during ischemia and the first 10 min of reperfusion in the desflurane group compared with the propofol group. Recovery from myocardial stunning in dogs was faster when desflurane was used at the time of ischemia as compared with propofol anesthesia. The mechanism for this difference is unclear, but sympathetic activation by desflurane was not a limiting factor for ischemic tolerance in chronically instrumented dogs.