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  • 1
    Electronic Resource
    Electronic Resource
    Do cardiac output and serum lactate levels indicate blood transfusion requirements in anemia of prematurity? (1996)
    Springer
    Intensive care medicine 22 (1996), S. 472-476 
    Details
    ISSN: 1432-1238
    Keywords: Anemia ; Preterm infants ; Serum lactate ; Cardiac output ; Oxygen saturation ; Blood transfusion ; Oxygen delivery
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Background Whether and when to transfuse in anemia of prematurity is highly controversial. Some authors suggest transfusions simply if the hemoglobin (Hb) level is below a defined normal range. Others propose the use of clinical or laboratory parameters in anemic patients to decide whether to transfuse or not. Hypothesis A decreasing amount of circulating Hb should cause a compensatory increase in cardiac output (CO) and an increase in arterial serum lactate. Materials and methods In 56 anemic preterm infants (not in respiratory or hemodynamic failure) we analyzed CO after the first week of life using a Doppler sonographic method. At the same time serum lactate levels. Hb levels and oxygen saturation were registered. Nineteen of these patients were given transfusion when they demonstrated clinical signs of anemia by tachycardia 〉180/min, tachypnea, retractions, apneas and centralization (group 2). The remaining 37 patients were not transfused (group 1). Serum lactate, CO, heart rate (HR), oxygen delivery, respiratory rate, capillary refill and Hb were analyzed in both groups and in group 2 before and 12–24 h after transfusion. Data between groups 1 and 2 and in group 2 before and after transfusion were compared. Results In the 56 patients studied no linear correlation between Hb and CO or between Hb and serum lactate was found. Nor could any correlation be demonstrated between the other variables studied Examining the subgroups separately a negative linear correlation was demonstrated between serum lactate and oxygen delivery in group 2. No other significant correlations were detected. However, when the pre- and post-transfusion data were compared in group 2 (increase of Hb from 9.45 (SD 3.44) to 12.5 (SD 3.8) g/100 ml), the CO decreased from 281. 3 (SD 162.6) to 224 (SD 95.7) ml/kg per min (p〈0.01) and serum lactate decreased significantly from 3.23 mmol/l (SD 2.07) before to 1.71 (SD 0.83) after transfusion. Oxygen delivery was 35.8 (±0.19) ml/kg per min group 1, 27.8 (±0.05) pre- and 43.4 (±0.07) post-transfusion in group 2 (p〈0.01). Conclusions CO measurements and serum lactate levels add little information to the decision-making process for blood transfusions, as neither CO nor serum lactate levels correlate with Hb levels in an otherwise asymptomatic population of preterm infants. In infants where the indication for blood transfusion is made based on traditionally accepted clinical criteria, serum lactate is an additional laboratory indicator of impaired oxygenation, as it correlates significantly with oxygen delivery. A significantly lower oxygen delivery in patients in whom blood transfusion is indicated and an increase in oxygen induced by transfusion demonstrate the value of these criteria in identifying preterm infants who benefit from transfusion.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01712170
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  • 2
    Electronic Resource
    Electronic Resource
    Viscoelasticity of the alar and transverse ligaments (1992)
    Springer
    European spine journal 1 (1992), S. 178-184 
    Details
    ISSN: 1432-0932
    Keywords: Rachis cervical supérieur ; Ligament alaire ; Ligament transverse ; Anatomie ; Biomécanique ; Upper cervical spine ; Alar ligament ; Transverse ligament ; Anatomy ; Biomechanics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Summary The occipito-atlanto-axial joint is the most complex one of the human spine. Traumatic or inflammatory lesions in this region may lead to instability and neurological symptoms of clinical importance. This study reports the results of anatomical and biomechanical examination of 13 human upper cervical spine specimens and focuses on the viscoelastic behavior of the alar and transverse ligaments. Non-destructive tensile testing was performed on a uniaxial testing machine with 25 alar and 11 transverse ligaments at three different load rates of 0.1 mm/s, 1.0 mm/s, and 10.0 mm/s. The ligaments were further tested for relaxation over 300 s. Each ligament exhibited an initial neutral zone in which no tensile force could be measured during cyclic testing. This neutral zone was more significant in the alar ligaments than in the transverse ligaments with respect to the measured in situ length of the ligaments (11.2 vs 18.1 mm on average). Increasing axial deformation led to increased load in all ligaments. Hysteresis, i.e., the energy loss exhibited by viscoelastic material subjected to loading and unloading cycles, increased with higher displacement rates and higher tensile forces. In neutral position the alar ligaments were lax in all specimens. During axial rotation both alars tightened. Ligamentous resistance increased as the end of the range of motion (ROM) was approchaed during rotation. The neutral zone explains the laxity of the ligaments in midposition and allows mobility of the upper cervical spine with minimum expenditure of muscular energy. The ligaments become stiffer under higher loads and therefore contribute to a limitation of the ROM in the occipitio-atlanto-axial joint.
    Notes: Résumé L'articulation occipito-atlanto-axoïdienne est l'une des plus complexes du rachis humain. Les lésions traumatiques ou inflammatoires de cette région peuvent conduire à l'instabilité et à des troubles neurologiques importants. Cette étude rapporte les résultats d'une étude anatomique et biomécanique de 13 spécimens de rachis cervical supérieur et met l'accent sur le comportement visco-élastique des ligaments alaires et transverse. Des essais de mise en tension ont été réalisés sur 25 ligaments alaires et 11 ligaments transverses, en restant en deçà du point de rupture. Ils ont été effectués sur un appareil monoaxial, selon trois niveaux de charge différents: 0.1 mm/s, 1.0 mm/s et 10.0 mm/s. La détente ligamentaire a été en outre étudiée pendant 300s. Chaque ligament a montré une zone neutre initiale (NZ) dans laquelle aucune force de tension ne pouvait être mesurée au cours du cycle d'essai. Cette zone neutre était plus importante pour les ligaments alaires que pour les ligaments transverses, compte tenu de la longueur ligamentaire mesurée in situ (11.2 contre 18.1 mm en moyenne). L'augmentation de la déformation axiale a conduit à une augmentation des contraintes dans tous les ligaments. L'hystérésis, c'est à dire la perte d'énergie présentée par le matériel visco-élastique soumis à des cycles de mise en charge et décharge, augmentait avec l'amplitude du déplacement et l'intensité des forces de tension. En position neutre, les ligaments alaires étaient détendus sur tous les spécimens. Lors de la rotation axiale, les deux ligaments alaires se sont mis en tension. La résistance du ligament à la rotation s'est trouvée accrue en fin d'amplitude. La zone neutre explique la laxité des ligaments en position intermédiaire et permet la mobilité du rachis cervical supérieur avec un minimum de dépense d'énergie. Les ligaments se tendent sous des charges plus élevées et par conséquent contribuent à la limitation de ROM dans l'articulation occipito-atlanto-axoïdienne.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00301310
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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    Results of lumbosacral distraction spondylodesis for the treatment of spondylolisthesis, failed-back syndrome, and lumbar instability (1992)
    Springer
    European spine journal 1 (1992), S. 117-124 
    Details
    ISSN: 1432-0932
    Keywords: Rachis lombaire ; Arthrodèse lombaire ; Spondylolisthésis ; Echec de la chirurgie lombaire ; Biomécanique ; Lumbar spine ; Spinal fusion ; Spondylolisthesis ; Failed-back syndrome ; Biomechanics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Summary Various methods of lumbosacral fusions for the treatment of degenerative spinal diseases are used clinically. Results vary greatly depending on indication, type of fusion, implants, and method of evaluation. In a retrospective clinical and radiological examination after an average follow-up time of 3.9 years this study reports on the outcome of lumbosacral distraction spondylodesis (LSDS) in a consecutive series of 147 patients being fused for the treatment of spondylolisthesis, failed-back syndrome, or lumbar instability. LSDS consists of a posterolateral fusion together with an autologous corticocancellous H-graft wedged under distraction between the spinous processes of L4 and S1. With 81.0% good and excellent results this noninstrumented fusion technique showed the best outcome in patients with spondylolisthesis, while in cases with a failed-back syndrome or lumbar instability only 62.3% excellent to satisfying outcomes were noted. The rate of pseudarthrosis was 13.6% in the whole patient group; no major complications such as nerve root damage, postoperative neurological deficits, or spinal stenosis were found.
    Notes: Résumé Diverses méthodes de fusion lombo-sacrée sont utilisées dans le traitement des affections dégénératives rachidiennes. Les résultats sont très variables et dépendent de l'indicatio, du type de fusion, des implants et de la méthode d'évaluation. Par une analyse rétrospective clinique et radiologique après un délai postopératoire moyen de 3,9 mois, cette étude rend compte du résultat de la “spondylodèse lombo-sacrée en distraction” (LSDS) dans une série consécutive de 147 patients traités par arthrodèse pour spondylolisthésis, échec de la chirurgie lombaire ou instabilité lombaire. La LSDS consite en une greffe postéro-latérale associée à un greffon autologue cortico-spongieux en H enfoncé sous distraction entre les épineuses de L4 et de S1. Avec 81,0% de bons et excellents résultats, cette technique d'arthrodèse sans ostéosynthèse a montré ses meilleurs résultats dans le traitement des spondylolisthésis, tandis que dans les cas d'échec de la chirurgie lombaire ou d'instabilité lombaire il n'a donné que 62,3% des résultats excellents ou satisfaisants. Le taux de pseudarthroses était de 13,6% pour tout le groupe et l'on n'a pas trouvé de complications majeures comme une atteinte radiculaire, un déficit neurologique post-opératoire ou une sténose lombaire.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00300938
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    Paper (German National Licenses)
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