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Biomedical subjects

L Doni

Publications and source records attributed to L Doni.

13 recordsLinked to original sources

Postspinal headache in Taylor's approach: a comparison between 21- and 25-gauge needles in orthopaedic patients.

A randomized study was carried out on 160 patients aged 30-60 years with the aim of finding a method of preventing postdural puncture headache (PDPH). In Taylor's lumbosacral approach to the subarachnoid space, two different needle sizes were used (21-gauge versus 25-gauge) for injecting the anaesthetic solution. Our results show an overall incidence of PDPH in nearly 8% of patients, with no significant difference related to the size of the needle employed. Patients with PDPH showed mild symptoms which disappeared in a short time and none needed epidural blood patching. The possibility of using larger needles, facilitating the execution of the block without increasing PDPH incidence, renders this technique particularly attractive in patients where the midline approach is not feasible, or when pencil-point needles are not available.

Adult

The orthogonal two-needle technique: a new axillary approach to the brachial plexus.

Ninety-eight patients scheduled for elbow, forearm, wrist or hand surgery were allocated randomly to one of two different techniques of brachial plexus block, both using the axillary approach. The blocks were all performed at the level of the insertion of the lateral margin of the pectoralis major muscle on the humerus. The same mixture and volume of anaesthetic solution (30 mL of a mixture of equal parts of 0.5% bupivacaine with adrenaline 1:200 000 and 2% lignocaine) was injected through two needles positioned above and below the axillary artery, in the fascial compartments containing the median and ulnar nerves, respectively. Confirmation of correct needle placement was obtained by elicitation of paraesthesias. In one group of patients (n = 40) the needles were inserted parallel to the axillary artery pathway and the anaesthetic solution was injected toward the apex of the axilla. In a second group (n = 58) the needles were inserted orthogonally with respect to the neurovascular bundle pathway, aimed towards the posterior fascial compartment containing the radial nerve. Using the second technique, all the terminal branches of the brachial plexus were more frequently involved in the block, including the distribution of the musculocutaneous nerve. It seems likely that the inclination of the needles causes a preferential spread of the anaesthetic solution which follows the direction of the needle shaft.

Adolescent

[Fibromyalgia and trigger points].

Trigger points in chronic pain and myofascial syndromes are often localized at a distance from the painful area. Infiltration of trigger points with Bupivacaine 0.5% greatly reduces pain and can eliminate it with no need of any other analgesic therapy.

Adolescent

How many interscalenic blocks are there? A comparison between the lateral and posterior approach.

This study compares the areas of analgesia obtained with the lateral and posterior approaches to the interscalene space after injection of equal volumes of anaesthetic solution (40 ml of a mixture of 0.5% bupivacaine with adrenaline 1:200,000 and 2% lignocaine in equal parts). There was a significant difference in the distribution of the areas of analgesia between the two approaches. With the posterior approach, the region supplied by the radial, medial and ulnar nerves and the post-axial border of the upper limb were more frequently involved, whilst with the lateral approach the area of analgesia was usually confined to the regions supplied by the most caudal roots of the cervical plexus and the upper trunk of the brachial plexus (pre-axial border of the upper limb). On these grounds it appears that two different types of interscalene block are possible.

Adolescent

Defibrotide in extracorporeal circulation on healthy rabbits.

Defibrotide, a partially depolymerized DNA fraction obtained from mammalian lung, was found to have significant antithrombotic and fibrinolytic activities. On the basis of this evidence defibrotide could be of clinical value during hemoperfusive treatment. The present study was designed to evaluate the biological tolerance of this technique in a model of extracorporeal circulation, using an original Silastic apparatus, with defibrotide (0.83 mg/kg-1/min-1 after a 50 mg/kg-1 bolus injection) and heparin (0.66 IU/kg-1/min-1 after a 400 IU/kg-1 bolus injection) in ten rabbits (Group 1) and heparin only in ten others (Group 2, control group). In this study defibrotide produced a significantly lower pressure inside the circuit compared to the control group and gave a protective effect against those pathological changes which appeared during extracorporeal circulation and that may be considered omens of a state of shock. However the use of defibrotide in addition to heparin seemed to have a poor effect on platelet and leukocyte count alterations during application of this technique.

Animals

Pressure-induced metabolic activation of platelets demonstrated in vitro by determination of malondialdehyde formation.

Platelet rich plasma (PRP) exposed in vitro to 200 mm Hg above atmospheric pressure showed a significant increase in malondialdehyde (MDA) formation compared to PRP at atmospheric pressure. This difference is also evident when platelets are incubated with arachidonic acid. The increase of MDA demonstrates that the increased beta-thromboglobulin and platelet factor 4 in plasma and the shape changes of platelets after pressure stimulation in vitro that were described in a previous paper result from the release reaction. Pressure-induced effects in vivo are discussed.

Blood Platelets

Influence of platelet activation of erythrocyte deformability.

Erythrocyte deformability was demonstrated to be influenced by platelet activation. Deformability of erythrocytes suspended in autologous platelet poor plasma (PPP), obtained from platelet rich plasma (PRP), was significantly reduced when PRP had previously been incubated with a platelet activating substance (arachidonic acid, adrenaline or ADP). The possibility of a direct influence of the activating substance on erythrocyte deformability was examined and malondialdehyde formation was determined as an indicator of platelet activation. Erythrocyte deformability was not impaired when endoperoxide formation in platelets was blocked by an inhibitor of cyclooxigenase (acetylsalicylic acid). Plasma viscosity was not influenced by platelet activation as demonstrated by filtration and viscosimetry. Recent studies showed that prostacyclin (PGI2) increases erythrocyte deformability (1). The antagonistic action between prostacyclin released by vessel walls and products of platelet metabolism being well known, we discuss possible mechanisms of this effect and pathophysiological relevance of our results.

Aspirin

[How many interscalene blocks are there? Reflections on 109 cases studied with various techniques].

The effects of interscalene block were studied on 109 patients undergoing upper extremity elective orthopaedic surgery. Blocks were performed in a non-randomized manner with three different techniques, the site where anaesthetic solution was injected being the main distinguishing mark. The anaesthetic solution was injected into the interscalenic compartment both in the case of patients where classic technique had been carried out and in the group where the nerve stimulator had been used. In the "double needle" technique group, on the contrary, the anaesthetic solution was injected close to the vertebral column. The spread of analgesia involves the caudal portion of the cervical plexus and the cranial portion of the brachial plexus, but with the cervical plexus is almost certain to be involved, the brachial is not. Block outcome was related to the surgical procedure (surgery or orthopaedic manipulation), the site of surgery, paraesthesia elicitation, prolonged surgery and height, weight, age and sex of patients. Results also different according to the technique used. When the anaesthetic solution was injected close to the vertebral column analgesic cover was more widespread and lesser amounts of anaesthetic needed. When the block was performed within the interscalenic compartment, the analgesic cover was usually restricted to the area supplied by the primary superior trunk of the brachial plexus. The different results were explained by the presence of fibrous sheaths within the interscalenic compartment limiting spread of the anaesthetic, which are absent close to the vertebral column. Therefore two types of interscalene block were postulated: an intrascalene or troncular block within the interscalenic compartment and a radicular or paravertebral block close the vertebral column.

Adolescent