Biomedical subjects

B Eberle

Publications and source records attributed to B Eberle.

At least 55 records · Page 3Linked to original sources

PubMed1998

High-dose epsilon-aminocaproic acid versus aprotinin: antifibrinolytic efficacy in first-time coronary operations.

BACKGROUND: The antifibrinolytic efficacy of a high-dose regimen of epsilon-aminocaproic acid (epsilon-ACA) was compared with aprotinin in first-time coronary operations. METHODS: In a prospective, double-blinded, randomized study, 20 patients received high-dose epsilon-ACA (10 g both as a loading and cardiopulmonary bypass priming dose, 2.5 g/h until 4 hours after protamine), and another 20 patients received aprotinin (2 x 10(6) KIU [280 mg] for loading and priming, 0.5 x 10(6) KIU/h [70 mg/h]). Ten untreated patients served as controls. RESULTS: Both agents reduced postoperative levels of thrombin/antithrombin III complexes, D-dimers, fibrin degradation products, free plasma hemoglobin (epsilon-ACA versus aprotinin, p = not significant; p < 0.05 versus controls), and amount of retransfused autologous blood (p < 0.001). Epsilon-ACA increased, aprotinin suppressed antiplasmin-plasmin complex generation (epsilon-ACA versus controls, p < 0.02; epsilon-ACA versus AP, p < 0.0001). For 4 hours after discontinuation, more chest drainage occurred with epsilon-ACA than aprotinin (137 +/- 90 mL versus 62 +/- 29 mL; means +/- standard deviation; p < 0.02). Cumulative 12-hour drainage was similar for aprotinin (391 +/- 220 mL) and epsilon-ACA (582 +/- 274 mL), but higher without inhibitor (1,091 +/- 541 mL; p < 0.001 versus drugs). Postoperatively, aprotinin was associated with the lowest autologous retransfusion incidence and highest hematocrits (p < 0.01 versus epsilon-ACA). Homologous transfusion exposures did not differ. CONCLUSIONS: In first-time coronary operations, higher postoperative hematocrit and less shed blood retransfusion constitute only subtle advantages of aprotinin over high-dose epsilon-ACA.

Aminocaproic Acid↗

PubMed1998

Adaptive lung ventilation (ALV) during anesthesia for pulmonary surgery: automatic response to transitions to and from one-lung ventilation.

UNLABELLED: Adaptive lung ventilation is a novel closed-loop-controlled ventilation system. Based upon instantaneous breath-to-breath analyses, the ALV controller adjusts ventilation patterns automatically to momentary respiratory mechanics. Its goal is to provide a preset alveolar ventilation (V'A) and, at the same time, minimize the work of breathing. Aims of our study were (1) to investigate changes in respiratory mechanics during transition to and from one-lung ventilation (OLV), (2) to describe the automated adaptation of the ventilatory pattern. METHODS: With institutional approval and informed consent, 9 patients (33-72 y, 66-88 kg) underwent ALV during total intravenous anesthesia for pulmonary surgery. The ALV controller uses a pressure controlled ventilation mode. V'A is preset by the anesthesiologist. Flow, pressure, and CO2 are continuously measured at the DLT connector. The signals were read into a IBM compatible PC and processed using a linear one-compartment model of the lung to calculate breath-by-breath resistance (R), compliance (C), respiratory time constant (TC), serial dead space (VdS) and V'A. Based upon the results, the controller optimizes respiratory rate (RR) and tidal volume (VT) such as to achieve the preset V'A with the minimum work of breathing. In addition to V'A, only PEEP and FIO2 settings are at the anesthesiologist's discretion. All patients were ventilated using FIO2 = 1,0 and PEEP = 3 cm H2O. Parameters of respiratory mechanics, ventilation, and ABG were recorded during three 5-min periods: 10 min prior to OLV (1), 20 min after onset of OLV (II), and after chest closure (III). Data analyses used nonparametric comparisons of paired samples (Wilcoxon, Friedman) with Bonferroni's correction. Significance was assumed at p < 0.05. Values are given as medians (range). RESULTS: 20 min after onset of OLV (II), resistance had approximately doubled compared with (1), compliance had decreased from 54 (36-81) to 50 (25-70) ml/cm H2O. TC remained stable at 1.4 (0.8-2.4) vs. 1.2 (0.9)-1.6) s. Institution of OLV was followed by a reproducible response of the ALV controller. The sudden changes in respiratory mechanics caused a transient reduction in VT by 42 (8-59)%, with RR unaffected. In order to reestablish the preset V'A, the controller increased inspiratory pressure in a stepwise fashion from 18 (14-23) to 27 (19-39) cm H2O, thereby increasing VT close to baseline (7.5 (6.6-9.0) ml/kg BW vs. 7.9 (5.4-11.7) ml/kg BW). The controller was, thus, effective in maintaining V'A. The minimum PaO2 during phase II was 101 mmHg. After chest closure, respiratory mechanics had returned to baseline. CONCLUSIONS: Respiratory mechanics during transition to and from OLV are characterized by marked changes in R and C into opposite directions, leaving TC unaffected. The ALV controller manages these transitions successfully, and maintains V'A reliably without intervention by the anesthesiologist. VT during OLV was found to be consistently lower than recommended in the literature.

Adult↗

PubMed1998

Laryngeal mask airway position and the risk of gastric insufflation.

UNLABELLED: A potential risk of the laryngeal mask airway (LMA) is an incomplete mask seal causing gastric insufflation or oropharyngeal air leakage. The objective of the present study was to assess the incidence of LMA malpositions by fiberoptic laryngoscopy, and to determine their influence on gastric insufflation and oropharyngeal air leakage. One hundred eight patients were studied after the induction of anesthesia, before any surgical manipulations. After clinically satisfactory LMA placement, tidal volumes were increased stepwise until air entered the stomach, airway pressure exceeded 40 cm H2O, or air leakage from the mask seal prevented further increases in tidal volume. LMA position in relation to the laryngeal entrance was verified using a flexible bronchoscope. The overall incidence of LMA malpositions was 40% (43 of 108). Gastric air insufflation occurred in 19% (21 of 108), and in 90% (19 of 21) of these patients, the LMA was malpositioned. Oropharyngeal air leakage occurred in 42%, and was independent of LMA position. We conclude that clinically unrecognized LMA malposition is a significant risk factor for gastric air insufflation. IMPLICATIONS: Routine placement of laryngeal mask airways does not require laryngoscopy. In our study, fiberoptic verification of mask position revealed suboptimal placement in 40% of cases. Such malpositioning considerably increased the risk of gastric air insufflation.

Adult↗

PubMed1998

[A new method for imaging ventilation-distribution with 3Helium in magnetic resonance tomography].

BACKGROUND: Conventional 1H-MRI of the lung is restricted by susceptibility effects and low proton density: Recently, imaging of lung ventilation in MRI has become feasible using hyperpolarised inert gases with a spin of I = 1/2, such as 3He and 129Xe, as inhalative "contrast agents". New technical developments, preclinical and clinical application of this method are described. MATERIALS AND METHODS: With optical laser pumping high polarisation rates can be achieved, resulting in a high signal-to-noise ratio (S/N). A dedicated application system allows accurate administration of 3He boli at different time points during inspiration. Thus, dynamic ventilation imaging becomes possible. Prerequisites for this method include a dedicated coil as well as a spectroscopy option at the MRI system. Fast sequences and low flip angles are employed to comply with the relaxation of hyperpolarise 3He in vivo. RESULTS: Overall homogeneous signal intensity (SI) represents physiological conditions. Obstructive lung disease is associated with generalised or localised signal inhomogeneity. Different time constants of specific lung regions are probably responsible for this kind of inhomogeneous inspiratory distribution of ventilation. Tumours show a clear ventilation deficit, correlating with non-ventilated lung areas. CONCLUSION: 3He MRI is a promising new modality for the evaluation of ventilation distribution under different pathological conditions. This may include obstructive lung disease and assessment of ventilation distribution before and after thoracic surgery. Furthermore, evaluation of patients with acute lung failure and validation of ventilator settings in anaesthesia may be performed.

Contrast Media↗

PubMed1997

[Automated anesthesia record systems].

The introduction of electronic anaesthesia documentation systems was attempted as early as in 1979, although their efficient application has become reality only in the past few years. The advantages of the electronic protocol are apparent: Continuous high quality documentation, comparability of data due to the availability of a data bank, reduction in the workload of the anaesthetist and availability of additional data. Disadvantages of the electronic protocol have also been discussed in the literature. By going through the process of entering data on the course of the anaesthetic procedure on the protocol sheet, the information is mentally absorbed and evaluated by the anaesthetist. This information may, however, be lost when the data are recorded fully automatically-without active involvement on the part of the anaesthetist. Recent publications state that by using intelligent alarms and/or integrated displays manual record keeping is no longer necessary for anaesthesia vigilance. The technical design of automated anaesthesia records depends on an integration of network technology into the hospital. It will be appropriate to connect the systems to the internet, but safety requirements have to be followed strictly. Concerning the database, client server architecture as well as language standards like SQL should be used. Object oriented databases will be available in the near future. Another future goal of automated anaesthesia record systems will be using knowledge based technologies within these systems. Drug interactions, disease related anaesthetic techniques and other information sources can be integrated. At this time, almost none of the commercially available systems has matured to a point where their purchase can be recommended without reservation. There is still a lack of standards for the subsequent exchange of data and a solution to a number of ergonomic problems still remains to be found. Nevertheless, electronic anaesthesia protocols will be required in the near future. The advantages of accurate documentation and quality control in the presence of careful planning outweight cost considerations by far.

Anesthesia↗

PubMed1997

[Early results of pulmonary thromboendarterectomy in chronic thromboembolic pulmonary hypertension].

Pulmonary thromboendarterectomy (PTE) is a potentially curative procedure in chronic thromboembolic pulmonary hypertension. From June, 1989, to December, 1994, we performed PTE in 109 consecutive patients. Multiple changes in surgical approach and postoperative management have been implemented since January, 1995. We report the early results of 32 thromboendarterectomies performed from January, 1995, to January, 1997. Thirty-two patients (16 females, 16 males; mean age 55 years) were operated using cardiopulmonary bypass, deep hypothermia and circulatory arrest. Preoperative NYHA functional class was III in 21 and IV in 11 patients. Pulmonary vascular resistance (PVR) and mean pulmonary artery pressure (mPAP) were elevated to 967 +/- 238 dynes.s.cm-5 and 51 +/- 11 mm Hg respectively. The perioperative mortality rate was 9.3% (3 of 32). Twenty-nine survivors were weaned from mechanical ventilation and extubated after a mean of 35 hours (12 to 190 hours). PVR was reduced to 301 +/- 151 dynes.s.cm-5 (p < 0.001) and mPAP was reduced to 28 +/- 10 mm Hg (p < 0.001). Pulmonary thromboendarterectomy is an effective surgical procedure for chronic thromboembolic pulmonary hypertension. By means of modifications in surgical approach and postoperative management, early results can be improved and perioperative mortality can be decreased to less than 10%.

Chronic Disease↗

PubMed1997

High dose naloxone does not improve cerebral or myocardial blood flow during cardiopulmonary resuscitation in pigs.

In a prospective, randomized, placebo-controlled, double-blind trial we tested the hypothesis that naloxone given during cardiopulmonary resuscitation (CPR) enhances cerebral and myocardial blood flow. Twenty-one anesthetized, normoventilated pigs were instrumented for measurements of right atrial and aortic pressures, and regional organ blood flow (radiolabeled microspheres). After 5 min of untreated fibrillatory arrest, CPR was commenced using a pneumatic chest compressor/ventilator. With onset of CPR, an i.v. bolus of 40 micrograms/kg b.w. of epinephrine was given, followed by an infusion of 0.4 micrograms/kg per min. After 5 min of CPR, either naloxone, 10 mg/kg b.w. (group N, n = 11) or normal saline (group S, n = 10) was given i.v. Prior to, and after 1, 15, and 30 min of CPR, hemodynamic and blood flow measurements were obtained. After 30 min of CPR, mean arterial pressure was significantly higher in group N (26 +/- 5 vs. 13 +/- 3 mmHg, P < 0.05). Groups did not differ with respect to myocardial perfusion pressure or arterial blood gases at any time during the observation period. Regional brain and heart blood flows were not different between N and S at any point of measurement. We conclude that high-dose naloxone does not augment cerebral or myocardial blood flow during prolonged closed-chest CPR.

Acid-Base Equilibrium↗

PubMed1997

Evaluation of gastric intramucosal pH during and after pediatric cardiac surgery.

OBJECTIVES: In adult patients, intramucosal pH (pHi) has been advocated to detect postoperative complications. The purpose of our study was to evaluate this technique in pediatric patients during and after cardiac surgery. METHODS: Thirty-five infants (age: 5 days to 15 years, median 1.8 years; and weight: 3.2-32 kg, median 9.8 kg) were studied. pHi was measured before cardiopulmonary bypass (CPB), after 30 min of CPB, prior to weaning off CPB, at intensive care unit arrival, and 6, 12, 24, 48 and 72 h after surgery. RESULTS: There were no complications related to the tonometer. A pathologically low pHi < 7.32 was found during surgery in less than 17%, at intensive care unit arrival in 83% and after 48 h in 18%. pHi values were lower (P < 0.05) at intensive care unit arrival (7.25 +/- 0.08) and after 6 h (7.28 +/- 0.09) than afterwards. pHi correlated with arterial pH (r = 0.66), central-peripheral temperature difference (r = -0.36), lactate (r = -0.32) and central venous pressure (r = -0.21). Patients after a Fontan procedure had postoperatively a lower pHi than after other operations (P < 0.05). None of the patients died or developed organ failure. Six patients had signs of organ dysfunction. Their pHi (median 7.23, range 7.14-7.28) could not differentiate them from the other patients. CONCLUSIONS: With current equipment, tonometry cannot be recommended for the management of pediatric patients after cardiac surgery. However, as a semi-invasive method tonometry deserves further evaluation.

Adolescent↗

PubMed1997

[Spiral CT and 3-D reconstruction of the tracheobronchial tree for the selection of the proper double-lumen tubes before individual lung ventilation].

PURPOSE: To assess the potential of 3-D spiral CT in the selection of adequate double-lumen tubes (DLT) for one-lung-ventilation. MATERIALS AND METHODS: 3-D spiral CT of eight different DLTs was performed with standardized acquisition parameters: section thickness 4 mm, table speed 6 mm/s, increment 3 mm and standardised thresholds, window settings and magnification zoom. The accuracy was confirmed by measuring 3-D objects on screen and original DLTs by vernier caliper. 3-D spiral CT was performed in 20 patients preoperatively with slice thickness 4-8 mm, pitch 1-1.5, increment 4-8 mm. To select the adequate DLT size the 3-D reconstructions of the patient's tracheobronchial tree and of the DLT were superimposed by templates or computer animation. The accuracy was controlled by endoscopic and clinical measurements. RESULTS: The accuracy of the 3 D spiral CT was nearly 0.1 mm. The superimposition with templates was easy and reliable. The 3-D spiral CT determined DLTs were shown to fit perfectly by clinical and endoscopic measurements in all cases. CONCLUSION: 3-D reconstructions of the tracheobronchial tree obtained from routine preoperative spiral CT scans allow for an easy and accurate individual selection of double-lumen tubes.

Adult↗

PubMed1997

Respiratory mechanics, gastric insufflation pressure, and air leakage of the laryngeal mask airway.

A potential risk of the laryngeal mask airway (LMA) is incomplete mask seal, which causes air leakage or insufflation of air into the stomach. The objective of the present study was to assess respiratory mechanics, quantify air leakage, and measure gastric air insufflation in patients ventilated via the LMA. Thirty patients were studied after induction of anesthesia but prior to any surgical manipulations. After the insertion of the LMA, patients were ventilated with increasing tidal volumes until one of the three following end points were reached: 1) gastric air insufflation, 2) airway pressure > 40 cm H2O, or 3) limitation of further increase in tidal volume by air leakage. The following variables were determined:inspired volume (VI), expired volume (VE), maximum inspiratory pressure (Pmax), airway pressure at gastric inflation (Pinfl), respiratory time constant (RC), compliance (C), resistance (R), and leakage fraction (FL). Respiratory mechanics were in the physiological range. Gastric insufflation occurred in 27% of the patients at inspiratory pressures between 19 and 33 cm H2O. Air leakage of more than 10% was evident at inspiratory pressures between 25 and 34 cm H2O. The end point of 40 cm H2O airway pressure was reached in only three patients. We conclude that the LMA is not better in preventing airway pressure transmission to the esophagus than a conventional face mask. However, a high FL is associated with reduced gastric air insufflation.

Adolescent↗

PubMed1997

[Surgical aspects of pulmonary thrombendarterectomy].

Pulmonary thromboendarterectomy is an accepted operative procedure for treatment of pulmonary hypertension due to chronic embolism. Despite its proven value this procedure has been established at very few centers worldwide. In this paper we report our actual operative concept and operative results. Between 8'89 and 4'96 127 patients were operated with use of extracorporeal circulation, deep hypothermia and circulatory arrest. After analysis of the initial high perioperative mortality (26%, 29/108) our operative and postoperative concept changed since 11'94: 1. central incision of both pulmonary arteries, 2. endarterectomy exclusively during circulatory arrest, 3. prolonged reperfusion to 37 degrees C, 4. pressure controlled ventilation, NO-inhalation, early extubation, and 5. modified vasopressor therapy. Preoperatively 12 of the 19 patients were in NYHA class III and 6 in class IV. Mean pulmonary artery pressure was 52(17) mmHg with a calculated pulmonary resistance of 1013(579) dynes.s.cm-5. Mean circulatory arrest time was 37 min (19-57 min) (bypass time 345 min, (240-430 min)). Perioperatively two patients (11%) died (multiorgan failure; rethrombosis of pulmonary artery/right heart failure), all other patients survived (89%). Perioperative complications included reversible renal failure, delirium and postcardiotomy syndrome (1/2/1). Mean pulmonary resistance was postoperatively significantly reduced (362(124) dynes.s.cm-5) (p < 0.01). Early results of pulmonary thromboendarterectomy can be improved by consequent modifications of the intra- and postoperative concept.

Adolescent↗

PubMed1996

[Anesthesia in endovascular treatment of aortic aneurysm. Results and perioperative risks].

UNLABELLED: Surgical treatment of aortic aneurysms carries significant cardiovascular risks. Transvascular insertion of endoluminal prostheses is a new, minimally invasive treatment for aortic aneurysms. The pathophysiology of this novel procedure, risks and benefits of different anaesthetic techniques, and typical complications need to be defined. METHODS: With their informed, written consent, 19 male patients aged 48-83 years of ASA physical status III and IV with infrarenal (n = 18) or thoracic (n = 1) aortic aneurysms underwent 23 stenting procedures under general endotracheal (n = 9), epidural (n = 8), or local anaesthesia with sedation (n = 6). Intra-anaesthetic haemodynamics, indicators of postoperative (p.o.) oxygenation and systemic inflammatory response, and perioperative complications were analysed retrospectively and compared between anaesthetic regimens. RESULTS: Groups were well matched with regard to morphometry and preoperative risk profiles (Table I). The use of pulmonary artery pressure monitoring, incidence of intraoperative hypotensive episodes, and p.o. intensive care was more frequent with general anaesthesia. Groups did not differ in total duration of anaesthesia care, incidence and duration of intraoperative hypertensive, brady-, or tachycardic periods, incidence of arterial oxygen desaturation, use of vasopressors, colloid volume replacements, or antihypertensives (Table 2). Postoperatively, all groups showed a similar, significant systemic inflammatory response, i.e., rapidly spiking temperature (p.o. evening: mean peak 38.5 +/- 1.0 degrees C). leucocytosis, and rise of acute-phase proteins without bacteraernia (Table 3). During this period, despite supplemental oxygen, pulse oximetry revealed temporary arterial desaturation in 13 of 18 patients (70%) (Table 3). In 3 patients, hyperpyrexia was associated with intermittent tachyarrhythmias (n = 3) and angina pectoris (n = 1). There was no conversion to open aortic surgery, perioperative myocardial infarction, or death. CONCLUSIONS: Regional and local anaesthesia with sedation are feasible alternatives to general endotracheal anaesthesia for minimally invasive treatment of aortic aneurysms by endovascular stenting. However, invasive monitoring and close postoperative monitoring are strongly recommended with either method. Specific perioperative risks in patients with limited cardiovascular or pulmonary reserve are introduced by the abacterial systemic inflammatory response to aortic stent implantation. Hyperpyrexia increases myocardial and whole-body oxygen consumption, and can precipitate tachyarrhythmias. Hyperfibrino-genaemia may increase the risk of postoperative arterial and venous thromboses. Close monitoring of vital parameters and prophylactic measures, including oxygen supplementation, low-dose anticoagulation, antipyretics, and fluid replacement are warranted until this syndrome resolves.

Aged↗

PubMed1996

[The effect of preischemic blood sugar concentration on hemodynamics and regional organ blood flow during and following cardiopulmonary resuscitation (CPR) in swine].

UNLABELLED: Blood glucose alterations prior to cerebral ischaemia are associated with poor neurologic outcome, possibly due to extensive lactic acidosis or energy failure. Cerebral effects of hyper- or hypoglycaemia during cardiopulmonary resuscitation (CPR) are less well known. In addition, little information is available concerning cardiac effects of blood glucose alterations. The aim of this study was to evaluate the effects of pre-cardiac-arrest hypo- or hyper-glycaemia compared to normoglycaemia upon haemodynamics, cerebral blood flow (CBF) and metabolism (CMRO2), and regional cardiac blood flow during CPR subsequent to 3 min of cardiac and respiratory arrest and after restoration of spontaneous circulation. METHODS: After approval by the State Animal Investigation Committee, 29 mechanically ventilated, anaesthetised pigs were instrumented for haemodynamic monitoring and blood flow determination by the radiolabeled microsphere technique. The animals were randomly assigned to one of three groups: in group 1 (n = 9) blood glucose was not manipulated; in group II (n = 10) blood glucose was increased by slow infusion of 40% glucose to 319 +/- 13 mg/dl; in group III (n = 10) blood glucose was lowered by careful titration with insulin to 34 +/- 2 mg/dl. After 3 min of untreated ventricular fibrillation and respiratory arrest, CPR (chest compressor/ventilator (Thumper) and epinephrine infusion) was commenced and continued for 8 min. Thereafter, defibrillation was attempted, and if successful, the animals were observed for another 240 min. Cerebral perfusion pressure (CPP), CBF, CMRO2, coronary perfusion pressure (CorPP), and regional cardiac blood flow were determined at control, after 3 min of CPR, and at 10.30, and 240 min post-CPR. RESULTS: In group 1. 4/9 animals (44%) could be successfully resuscitated; in group II 4/10 (40%); and in group III 0/10 (0%). Prior to cardiac arrest, mean arterial pressure, CPP, and CorPP in group III were significantly lower compared to groups I and II. In group I. CPP during CPR was 26 +/- 6 mmHg; CBF 31 +/- 9 ml/ min/100g CMRO2 3.8 +/- 1.2 ml/ min/100 g; CorPP 18 +/- 5 mmHg; and left ventricular (LV) flow 35 +/- 15 ml/min/100 g. In group II; CPP = 21 +/- 5; CBF 21 +/- 7; CMRO2 1.8 +/- 0.8; CorPP 16 +/- 6; and LV flow 22 +/- 9; and in group III: CPP 15 +/- 3; CBF 11 +/- 8; CMRO2 1.5 +/- 1.1; CorPP 4 +/- 2; and LV flow 19 +/- 10. During the 240-min post-resuscitation period, there were no differences in CBF, CMRO2, or LV flow between groups I and II. CONCLUSION: Hypoglycaemia prior to cardiac arrest appears to be predictive for a poor cardiac outcome, whereas hyperglycaemia does not impair resuscitability compared to normoglycaemia. In addition, hyperglycaemia did not affect LV flow, CBF, or CMRO2. However, it has to be kept in mind that haemodynamics and organ blood flow do not permit conclusions with respect to functional neurologic recovery or histopathologic damage to the brain, which is very likely to be associated with hyperglycaemia.

Anesthesia↗

PubMed1996

[Adaptive lung ventilation (AVL). Evaluation of new closed loop regulated respiration algorithm for operation in the hyperextended lateral position].

The lateral decubitus position is the standard position for nephrectomies. There is a lack of data about the effects of this extreme position upon respiratory mechanics and gas exchange. In 20 patients undergoing surgery in the nephrectomy position, we compared a new closed-loop-controlled ventilation algorithm, adaptive lung ventilation (ALV), which adapts the breathing pattern automatically, to the respiratory mechanics with conventionally controlled mandatory ventilation (CMV). The aims of our study were (1) to describe positioning effects on respiratory mechanics and gas exchange, (2) to compare ventilatory parameters selected by the ALV controller with traditional settings of CMV, and (3) to assess the individual adaptation of the ventilatory parameters by the ALV controller. The respirator used was a modified Amadeus ventilator, which is controlled by an external computer and possesses an integrated lung function analyzer. In a first set of measurements, we compared parameters of respiratory mechanics and gas exchange in the horizontal supine position and 20 min after changing to the nephrectomy position. In a second set of measurements, patients were ventilated with ALV and CMV using a randomized crossover design. The CMV settings were a tidal volume of 10 ml/kg body weight, a respiratory rate of 10 breaths/min, an I:E ratio of 1:1.5, and an end-inspiratory pause of 30% of inspiratory time. With both ventilation modes F1O2 was set to 0.5 and PEEP to 3 cm H2O. During ALV a desired alveolar ventilation of 70 ml/ kg KG.min was preset. All other ventilatory parameters were determined by the ALV controller according to the instantaneously measured respiratory parameters. Positioning induced a reduction of compliance from 61.6 to 47.9 ml/cm H2O; the respiratory time constant shortened from 1.2 to 1.08 s, whereas physiological dead space increased from 158.9 to 207.5 ml. On average, the ventilatory parameters selected by the ALV controller resembled very closely those used with CMV. However, an adaptation to individual respiratory mechanics was clearly evident with ALV. In conclusion, we found that the effects of positioning for nephrectomy are minor and may give rise to problems only in patients with restrictive lung disease. The novel ALV controller automatically selects ventilatory parameters that are clinically sound and are better adapted to the respiratory mechanics of ventilated patients than the standardized settings of CMV are.

Adult↗

PubMed1996

Checking the carotid pulse check: diagnostic accuracy of first responders in patients with and without a pulse.

International guidelines for cardiopulmonary resuscitation (CPR) in adults advocate that cardiac arrest be recognized within 5-10 s, by the absence of a pulse in the carotid arteries. However, validation of first responders' assessment of the carotid pulse has begun only recently. We aimed (1) to develop a methodology to study diagnostic accuracy in detecting the presence or absence of the carotid pulse in unresponsive patients, and (2) to evaluate diagnostic accuracy and time required by first responders to assess the carotid pulse. In 16 patients undergoing coronary artery bypass grafting, four groups of first responders (EMT-1: 107 laypersons with basic life support (BLS) training; EMT-2: 16 emergency medical technicians (EMTs) in training; PM-1: 74 paramedics in training; PM-2: 9 certified paramedics) performed, single-blinded and randomly allocated, carotid pulse assessment either during spontaneous circulation, or during non-pulsatile cardiopulmonary bypass. Time to diagnosis of carotid pulse status, concurrent haemodynamics and diagnostic accuracy were recorded. In 10% (6/59), an absent carotid pulse was not recognized as pulselessness. In 45% (66/147), a pulse was not identified despite a carotid pulse with a systolic pressure > or = 80 mmHg. Thus, although sensitivity of all participants for central pulselessness approached 90%, specificity was only 55%. Both sensitivity and, to a lesser degree, specificity improved with increasing training; blood pressure or heart rate had no significant effect. The median diagnostic delay was 24 s (minimum 3 s). When no carotid pulse was found, delays were significantly longer (30 s: minimum 13 s), than when a carotid pulse was identified (15 s; minimum 3 s) (P < 0.0001). Of all participants, only 15% (31/206) produced correct diagnoses within 10 s. Only 1/59 (2%) identified pulselessness correctly within 10 s. Our cardiopulmonary bypass model of carotid pulse assessment proved to be feasible and realistic. We conclude that recognition of pulselessness by rescuers with basic CPR training is time-consuming and inaccurate. Both intensive retraining of professional rescuers and reconsideration of guidelines about carotid pulse assessment are warranted.

Adult↗

PubMed1996

[Intravascular therapy of aortic aneurysms: initial clinical results].

PURPOSE: A clinical study aiming at examining the implantation technique and the clinical results of a new vascular prosthesis in endovascular therapy of aneurysms of the aorta. MATERIAL AND METHODS: In 21 patients (20 men of 55 to 87 years of age, average age 70 years) with aneurysms of the infrarenal abdominal aorta (AAA n = 19) and the thoracic aorta (n = 2), a self-expanding nitinol stent with outer Dacron sheath (tubular prosthesis n = 4; bifurcation prosthesis n = 17) was implanted by means of an F-18 introductory set after surgical opening of the inguinal artery. RESULTS: By means of the 4 tubular prostheses and 13 of the 17 bifurcation prostheses the aneurysm was bypassed completely. In 4 cases residual perfusion through leaks (n = 3) or collateral blood supply (n = 1) was seen. In 6 patients 7 complications occurred which did not require to be operated on. No patient died in consequence of the surgical intervention or during the hospital stay. Follow-ups up to 8 months after surgery did not reveal any late complications to date. CONCLUSIONS: Endovascular implantation of vascular prostheses is a promising new method for interdisciplinary treatment of aneurysms of the aorta.

Aged↗

PubMed1995

Does standardized mega-code training improve the quality of pre-hospital advanced cardiac life support (ACLS)?

The aim of our prospective study was to evaluate the effects of a standardized mega-code and arrhythmia training upon process elements of quality of pre-hospital advanced cardiac life support provided by a physician-staffed mobile intensive care unit. In 145 cases of adult cardiac arrest due to cardiac aetiology, time intervals from arrival of the mobile intensive care unit at the patient's side until first ECG diagnosis, first defibrillation, endotracheal intubation, and first epinephrine administration were measured with on-line tape recording, prior to, and following a standardized 8-h arrhythmia and mega-code training. Following the training, patients with asystole or pulseless electrical activity were intubated 1.1 min earlier (P = 0.03), and received epinephrine 1.3 min earlier (P = 0.01) than prior to the training. There were no significant differences in time intervals concerning management of ventricular fibrillation or tachycardia. Neither admission nor discharge rates differed significantly before and after the training. Thus, practical training including rhythm analysis and mega-code session improved the performance of our mobile intensive care unit in cases of asystole and pulseless electrical activity, and, hence, process elements of quality.

Aged↗

PubMed1995

Improved procedure for the purification of selenoprotein Ph from human plasma.

Selenoprotein Ph, the human analogue of selenoprotein P from rat plasma, was purified from human plasma using Heparin Sepharose chromatography, PEG precipitation, DEAE ion exchange chromatography. RP chromatography, SDS-PAGE and electroelution. SDS-PAGE of the purified protein revealed one broad-selenium containing protein band from 56 to 67 kDa with a selenium maximum at 62 kDa. Using a 7.5% T gel this band was separated into two distinct selenium-containing bands with molecular weights of 61 and 64 kDa.

Blood Proteins↗