Effects of inoculum source, pH, redox potential and headspace di-hydrogen on rumen in vitro fermentation yields.

This in vitro study aimed at understanding how abiotic, that is chemical and electrochemical potentials, and biotic factors combine to impact the outputs of rumen volatile fatty acid (VFA). Using a 48-run design optimized by means of an exchange algorithm, the curvilinear effects of pH, Eh and partial pressure of dihydrogen (H2) on fermentation yields were investigated in 6-h batch cultures of mixed rumen microbes, fed on glucose so as to bypass the enzymatic hydrolysis and conversion steps preceding the glycolytic pathway. The role played by rumen microbiota in the expression of these effects was explored by testing three inocula grown on feeds supplying a microflora adapted to fibre, slowly degradable or readily degradable starch as the dominant dietary polysaccharide. Data were fitted to 2nd-order polynomial models. In fibre-adapted cultures, the yields of major VFA were mainly influenced by pH and H2 partial pressure, in opposite ways. In wheat grain-adapted cultures, the VFA yields underwent the opposite influences of pH, in a curvilinear way for propionate, and Eh since acetate production yield was not significantly modified by any factor. In maize grain-adapted cultures, acetate production yield was not modified by any factor but H2 in a quadratic way when the production yields of higher VFA underwent opposite influences of pH and Eh. In conclusion, the effects of environmental factors were dependent on the nature of the inoculum, a major source of variation, and more particularly on its adaptation to high- or low-fibre diets. These effects were loosely interrelated, the pH being the most active factor before the Eh and H2 partial pressure.

Arterial oxygen tension increase 2-3 h after hyperbaric oxygen therapy: a prospective observational study.

BACKGROUND: Inhalation of hyperbaric oxygen (HBO) has been reported to decrease arterial oxygen tension (PaO(2)) in the early period after exposure. The current investigation aimed at evaluating whether and to what extent arterial blood gases were affected in mechanically ventilated intensive care patients within 6 h after HBO treatment. METHODS: Arterial blood gases were measured in 11 ventilated subjects [nine males, two females, synchronized intermittent mandatory ventilation (SIMV) mode] undergoing HBO therapy for necrotizing soft tissue infection (seven patients), burn injury (two patients), crush injury (one patient) and major abdominal surgery (one patient). Blood gases were obtained with the patients in the supine position under continuous analgesia and sedation before the hyperbaric session (baseline), during isopression, after decompression, after each transport, and 1, 2, 3 and 6 h after exposure. Heart rates and blood pressures were recorded. Intensive care unit (ICU) ventilator settings remained unchanged. Transport and chamber ventilator settings were adjusted to baseline with maintenance of tidal volumes and positive end-expiratory pressure (PEEP) levels. The hyperbaric protocol consisted of 222.9 kPa (2.2 absolute atmospheres) and a 50-min isopression phase. The paired Wilcoxon's test was used. RESULTS: Major findings (median values, 25%/75% quartiles) as per cent change of baseline: PaO(2) values decreased by 19.7% (7.0/31.7, P < 0.01) after 1 h and were elevated over baseline by 9.3% (1.5/13.7, P < 0.05) after 3 h. SaO(2), alveolar-arterial oxygen tension difference and PaO(2)/FiO(2) ratio behaved concomitantly. Acid-base status and carbon dioxide tension were unaffected. CONCLUSION: Arterial oxygen tension declines transiently after HBO and subsequently improves over baseline in intensive care patients on volume-controlled mechanical ventilation. The effectiveness of other ventilation modes or a standardized recruitment manoeuvre has yet to be evaluated.

Stenting of the superficial femoral artery after suboptimal balloon angioplasty: one-year results.

AIM: The aim of this study was to analyze the intermediate results of selective stenting of superficial femoral artery (SFA) lesions after a suboptimal balloon angioplasty result. METHODS: We analyzed 70 consecutive patients with claudication or critical limb ischemia due to peripheral arterial occlusive disease who underwent stent implantation of the SFA after unsuccessful balloon-angioplasty. All patients were followed-up immediately after the procedure and 3, 6 and 12 months thereafter. Restenosis was defined as an increase of peak systolic velocity-index >2 as determined by duplex sonography. RESULTS: Primary patency rates at 3, 6 and 12 months were 83.4%, 66.2% and 59%, respectively. Successful reinterventions were performed for 17 reobstructions, resulting in a secondary patency rate at 3, 6 and 12 months of 91%, 89.3%, and 83.8%, respectively. At 12 months 68.6% of the patients were asymptomatic, 21.6% complained of mild (Fontaine class II a), 5.9% of severe (Fontaine class II b) claudication and 2.9% were in critical limb ischemia. CONCLUSIONS: Our data indicate that selective stenting of the SFA after suboptimal balloon angioplasty results in intermediate patency rates similar to that reported for primarily successful PTA, thereby supporting the widely accepted policy of selective stenting as a rescue procedure after unsuccessful balloon angioplasty.

Hemodynamic and oxygenation profiles in the early period after hyperbaric oxygen therapy: an observational study of intensive-care patients.

BACKGROUND: We studied whether hemodynamic and oxygenation profiles are altered in critically ill patients after exposure to hyperbaric oxygen (HBO). METHODS: Ten intensive-care patients (two females, eight males) undergoing HBO treatment after major abdominal surgery, after burn injury and after CO poisoning were included. All subjects were put on mechanical ventilation and received continuous sedation, and had HBO treatment at 2.2 absolute atmospheres for 50 min. DESIGN: Observational prospective study, and repeated measure design. RESULTS: Hemodynamic and oxygen transport patterns were determined before (C0), 1 h (C1) and 2 h (C2) after HBO therapy with continuous cardiac output dual oximetry pulmonary arterial catheter, a central venous and radial arterial line. Data were analyzed with non-parametric repeated measure analysis. Key results are expressed as a percentage of baseline (C0 values correspond to 100%) at C1 and C2 (median values, lower and upper limit of confidence interval): cardiac index [C1: 105% (98-135), C2: 99% (91-117), P = 0.19], systemic (P = 0.62) and pulmonary vascular (P = 0.76) resistance indices were unchanged, but pulmonary venous admixture (Qs/Qt) increased [C1: 173% (112-298), C2: 140% (92-241), P = 0.00002)] and arterial oxygen tension decreased [C1: 76% (67-94), C2: 82% (72-112), P = 0.010]. CONCLUSION: The hemodynamic profile remained unaffected. The increase in Qs/Qt and the decrease in PaO2 may be attributed to the inhalation of HBO, and both are reversible.

Differential lung ventilation and emergency hyperbaric oxygenation for repair of a tracheal tear.

PURPOSE: To report the anaesthetic management of a case of tracheal rupture, using different types of ventilation and additional hyperbaric oxygenation (HBO). CLINICAL FEATURES: An 8 cm postintubation tracheal tear was repaired in a 66-yr-old woman with acute myocardial reinfarction, mediastinal and subcutaneous emphysema, cardiac failure and unrecognized lymphoma. Intraoperative monitoring included dual oximetry: arterial (SaO2) and mixed venous saturations (SvO2). Maintenance of free surgical access and a series of life-threatening events like dislocation of the jet catheter required many ventilation modes. An episode of supraventricular tachycardia was interrupted by cardioversion. Differential lung ventilation with a combination of conventional and high-frequency jet ventilation (HFJV) modes preserved oxygenation (PO2 139.2 mm Hg, PCO2 42.4 mm Hg, FiO2 1.0) until acute tube obstruction and decrease of saturation values (SaO2 58%, SvO2 45%) required emergency HBO: immediate cardiac and respiratory stabilization was provided by double-lung HFJV and apneic oxygenation under hyperbaric conditions at 2.5 atmospheres absolute for 35 min (SaO2 100%). The patient recovered from surgery but died of non-Hodgkin lymphoma. CONCLUSION: The combination of different ventilation modes including HFJV and the additional use of HBO resulted in sufficient oxygenation during tracheal repair.

Operations on patients deemed "unfit for operation and anaesthesia": what are the consequences?

BACKGROUND: The decision "patient unfit for anaesthesia and operation" is likely to cause a delay of the scheduled operation. This retrospective evaluation was done: 1) to determine the correctness of preoperative tentative diagnoses of coexisting diseases making anaesthesia and operation excessively risky in relation to the physician's training status; 2) to examine the question of whether preoperative medical management modified according to the anaesthesiologist's suggestions had a positive impact on the perioperative course. METHODS: The medical records of patients scheduled for elective non-cardiac surgery who were rated "unfit for operation and anaesthesia" were evaluated. The accuracy of the tentative diagnoses was examined for relation to the training status of the anaesthesiologists. The preoperative management was tested for its impact on postoperative outcome. RESULTS: During the observation period 16,122 patients underwent preoperative anaesthesiological assessment; 1021 (6.3%) were initially considered to be unfit for operation and anaesthesia. The records of 807 patients were available for review. The accuracy of the tentative diagnoses was 70%, and was not significantly affected by the training status of the physicians (P = 0.022). Four hundred and seventeen patients were excluded from the second part of the investigation (discharged without operation, underwent operation using local anaesthesia or tentative diagnosis not confirmed). Three hundred and ninety patients were operated under general anaesthesia. Group I (n = 216) was managed according to the anaesthesiologist's suggestions and was found to have a significantly lower complication rate (18.1%) than group II (n = 174) in which the suggestions from the preoperative assessment were ignored (32.2%; P < 0.05). The perioperative mortality rate in group I was 2.3% compared with 5.2% in group II (n.s.; P > 0.05). CONCLUSIONS: We conclude that the anaesthesiology decision "patient unfit for operation and anaesthesia" has a high accuracy, independent of the anaesthesiologist's training status, and that preoperative medical management significantly reduces complications.

B1 bradykinin receptors and carboxypeptidase M are both upregulated in the aorta of pigs after LPS infusion.

Bradykinin receptor subtypes were characterized in aortic cryosections obtained from healthy normal pigs, animals that were given an LPS infusion, and animals that came with a pre-existing infection or inflammation to the laboratory by binding studies and in vitro autoradiography. In control aorta a single class of high affinity B2 binding sites, located within the endothelium, but with no significant binding of B1 ligand were identified. No major changes in the expression of B2 BK receptors were noted in inflammed tissues. In cryosections of inflammed vascular tissue a markedly increased endothelial carboxypeptidase M activity was verified that parallelled an upregulation of B1 receptors in the aortic smooth muscle layer. In crosstalk between endothelial cells and smooth muscle cells B1 receptor mediated functional responses may counteract some of the detrimental effects of inflammation.

Resource utilisation in haemophiliacs treated in Europe: results from the European Study on Socioeconomic Aspects of Haemophilia Care. The European Socioeconomic Study Group.

The objectives of our study was to answer the following questions: (1) What are the socioeconomic costs and benefits of different haemophilia treatment strategies? (2) Which savings can be achieved through a comprehensive care program? (3) How are haemophiliacs integrated into their social life? (4) What are the annual costs of treating haemophilia from a third party payer perspective? In this cross-sectional study, 840 consecutive haemophiliacs attending 16 haemophiliac treatment centres in 10 European countries at were entered in the study. The following six parameters were analysed: sociodemographic patient data, the type of substitution (on demand or prophylaxis), transfusion-transmitted diseases, the functional joint status, quality of life as well as the total costs of therapy. Three kinds of substitution modalities were distinguished: on demand therapy, pure and modified prophylaxis. The average number of medical visits, the average length of hospital stay, regular drug therapy and the average number of days off work per bleeding joint were recorded from the medical charts as a basis for the subsequent assessment of the costs of therapy. The total study sample comprised of 566 patients. Interestingly, statistically more significant (P = 0.0005) patients were unemployed in the on-demand group (14%) than in the prophylaxis group (3.4%). There was a higher ratio of white collar workers in the on-demand group as compared to the prophylaxis group and vice versa for blue collar workers. The distribution of blue collar workers, clerk, self-employed persons, students and housemen were quite comparable between the patients of the on-demand and prophylactic therapeutic regimen. The labor force participation rate was 55.2% in the patients in the on demand and 59.3% in the patients in the modified prophylactic group. The labor force participation rate across all patients was 56%. Patients on demand therapy used on average 38.3 (median: 12.5) units/kg/week as compared to 68.6 (median: 6) units/kg/week in the prophylaxis group. The mean usage across all patients was 46.1 (median 19.7) units/kg/week. There were an average of 7.4 (median: 3) joint bleeds per patient across all patients during the 6-month observation period. In the on-demand group 8.8 (median: 5) joint bleeds were recorded versus 3.1 joint bleeds (median: 0) in the prophylactic group. This difference was statistically different (95% CI of difference: 4.33-7.07). Our data suggest that patients receiving prophylactic clotting factor therapy require less additional health care resources, mainly due to the reduction in the number of joint bleeds.

Comparison of two preoperative indices to predict perioperative mortality in non-cardiac thoracic surgery.

OBJECTIVE: The preoperative classifications: physical status of the American Society of Anesthesiologists (ASA-PS) and/or cardiac risk index (CRI) of Goldman are widely used to estimate the perioperative risk in patients undergoing noncardiac throacic surgery. We tried to determine the validity of both methods in predicting the perioperative mortality in 845 consecutive patients scheduled for major elective noncardiac thoracic surgery. METHODS: Preoperatively, each patient was assigned 2 independent estimations of risk according to the ASA-score (ASA grade, I-IV) and CRI score (CRI grade, I-IV), respectively. RESULTS: Twenty-five patients died within 4 weeks after the operation, the others survived the perioperative period. The grading according to ASA as well as to the CRI score showed a direct correlation with the outcome: The higher the preoperative score, the higher was the mortality rate. When various combinations of ASA and CRI were tested, the lowest mortality rate was found in presence of ASA < or = III and CRI = I. Multivariate regression analysis showed that the ASA score had an independent correlation with perioperative mortality, whereas such a relationship was absent for CRI. CONCLUSIONS: The subjective assessment by an experienced anesthesiologist as expressed by the ASA-score is a valid method in the determination of the perioperative risk. CRI does not contribute additional information for the general perioperative risk.

Prehospital point of care testing of blood gases and electrolytes - an evaluation of IRMA.

BACKGROUND: This study evaluated the feasibility of blood gas analysis and electrolyte measurements during emergency transport prior to hospital admission. RESULTS: A portable, battery-powered blood analyzer was used on patients in life threatening conditions to determine pH, pCO2, pO2, sodium, potassium and ionized calcium. Arterial blood was used for blood gas analysis and electrolyte measurements. Venous blood was used for electrolyte measurement alone. During the observation period of 4 months, 32 analyses were attempted on 25 patients. Eleven measurements (34%) could not be performed due to technical failure. Overall, 25 samples taken from 21 patients were evaluated. The emergency physicians (all anesthesiologists) considered the knowledge of blood gases and/or electrolytes to be helpful in 72% of cases. This knowledge led to immediate therapeutic consequences in 52% of all cases. After a short training and familiarization session the handling of the device was found to be problem free. CONCLUSIONS: We concluded that knowledge of the patients' pH, pCO2 and pO2 in life threatening situations yields more objective information about oxygenation, carbon dioxide and acid-base regulation than pulse oximetry and/or capnometry alone. Additionally, it enables physicians to correct severe hypokalemia or hypocalcemia in cases of cardiac failure or malignant arrhythmia.

Autoradiographic visualization of B1 bradykinin receptors in porcine vascular tissues in the presence or absence of inflammation.

B1 bradykinin receptors were visualized by using the B1 bradykinin receptor agonist [3H]des-Arg10-kallidin in receptor autoradiography experiments. Cryosections were prepared from arterial vessels from a healthy control pig, a pig with pre-existing inflammation and an animal with experimental sepsis induced by an infusion of bacterial lipopolysaccharide (LPS). Only diffusely scattered silver grains with no preference for a distinct tissue structure were detected on emulsion-coated coverslips above the cryosections from the healthy control animal. This indicates that under normal circumstances no or only minute amounts of B1 bradykinin receptors are present in these tissues. In contrast, a 3-fold increase in specific B1 bradykinin receptor binding was observed on both the corresponding preparations of the sick piglet and of that with experimentally induced sepsis. A similar enhancement of specific [3H]des-Arg10-kallidin binding occurred in preparations devoid of endothelium. By comparison with the stained cryosection on the slide the silver grains showed a preferential distribution above smooth muscle cells. Taken together our data are consistent with the hypothesis that B1 bradykinin receptors are induced in the muscle layer of large vessels not only after experimentally-induced sepsis but also in pre-existing inflammatory disease.

Socioeconomic impact of haemophilia care: results of a pilot study.

Fifty consecutive haemophiliacs were entered into a pilot study of socioeconomic impact of haemophilia treatment. The Short Form 36 was used as an instrument for the assessment of quality of life. Direct and indirect costs were analysed. Incremental cost-effectiveness was expressed as additional costs per joint bleed avoided by prophylactic treatment over on-demand treatment. Thirtynine patients (mean age 35.14 years) were substituting factor VIII according to an on-demand and 11 patients according to a modified prophylactic regimen. There were an average of 9.84 joint bleeds per patient across all patients during the 6-month observation period: on-demand group 10.74 bleeds, prophylactic group 6.64 bleeds. This difference was not statistically different. Significant differences between haemophiliac patients and healthy men were seen in the assessment of their limitations of physical activities, limiting pain and general health. The total cost per patient during the 6 months was DM 24 601 in all patients, DM 17 253 in those on an on-demand base and DM 28 245 in the modified prophylactic group. Patients experienced an average 4.71 days off work: on demand 5.81 days, prophylactic regimen 0 days. The total indirect cost per patient was DM 683; therapy cost per patient was DM 25 284; cost per avoided bleed DM 1680 for on-demand therapy and DM 4228 on prophylaxis. The incremental cost-effectiveness, i.e. the additional costs to avoid one additional joint bleed by prophylactic treatment, was DM 2536. In conclusion, patients receiving prophylactic clotting factor therapy require less additional health care resources, mainly due to the reduction in the number of joint bleeds.

[Socioeconomic studies of hemostaseologic therapy and anticoagulation]. / Sozioökonomische Untersuchungen zur hämostaseologischen Therapie und Antikoagulation.

Since hemostaseologic therapies have a great impact on the budget of public health insurance companies, the therapy of hemophilia, prophylaxis of thrombosis and thrombolysis should be evaluated in a socioeconomic way. The substitution therapy in hemophilia is consuming a great deal of health care resources. The patients require an expensive, chronic therapy which enables them to be integrated in a normal social life. A lot of patients get a prophylaxis against thrombosis. Anticoagulants have to be valued with respect to their cost-effectiveness-relation. If thrombolysis is evaluated economically, one will have to consider carefully the high letality of thrombosis, the savings for the prevention of an operation and the high impact of this therapy on health care bills. The steady increase in health care costs emphasizes the necessity of health economics. Physicians should run socioeconomic evaluations to prove the use of different medicines and therapies and to represent the clinical point of view and the part of the patients.

The performance of optical systems with quasi-monochromatic partially coherent illumination.

The design and the prediction of the imagery of an optical system that is used with partially coherent illumination are complicated by the nonlinearities of this operation. The performance of the optical system is affected by both the nature of the illumination and the characteristics of the object, as well as by the aberrations of the system. A program for computing the energy distribution in the images of a class of standard objects as a function of the illumination and the pupil function of the optical system has been written. The theoretical approach is similar to that described by H. H. Hopkins in 1957.

MTF Maximization at Low Spatial Frequencies.

A merit function suggested by Lenskii has been generalized to make it applicable to optical systems with noncircular and/or partially obscured apertures. An independent derivation makes clear the relation between Lenskii's merit function and one due to Hopkins. A slight modification of the merit function relates it more accurately to the MTF.

Design and specification criteria for optical data processors.

The specification of coherent optical data processor components on the basis of approximate analogs and the inability of the optical designer to relate actual performance requirements to lens ray tracing computations have often resulted in systems that are disappointing in their results. Designing and manufacturing such systems to desired performance standards require a knowledge of both the communications and practical optical engineering aspects of the problem. The manner in which real coherent optical systems can be designed and assessed is illustrated by two examples. Quantitative criteria have been developed that are analogous to, but that differ significantly from, those used for assessing the quality of incoherent optical imaging systems. The usual computational methods available to optical designers are easily adapted to the evaluation of these criteria. The user can apply them to set specifications that are quantitatively related to the level at which his systems will perform.