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Biomedical subjects

I Curelaru

Publications and source records attributed to I Curelaru.

At least 37 records · Page 2Linked to original sources
PubMed1990

Disturbances of blood-flow velocity in the dorsal veins of the hand after vein cannulation and cannula fixation in the anaesthetised patient.

Modifications of the mean blood-flow velocity in the dorsal veins of the hand were assessed semi-quantitatively with continuous wave (CW) Doppler equipment in 32 anaesthetised patients (17 men and 15 women), 23-78 (median = 56) years of age, before and after venous catheterisation with cannula fixation to the skin. Cannulation of the vein caused a 48% reduction in the mean blood-flow velocity and made it impossible to detect any flow with the equipment used in 22% of the patients. A 10% further reduction in the mean blood-flow velocity and in the number of subjects with undetectable blood flow was observed after fixation of the cannulae. Age, small vein diameter, and hyperventilation (end-tidal carbon dioxide less than or equal to 3.5 volume % appeared to be significant factors reducing blood-flow velocities in the cannulated veins. It is concluded that venous catheterisation and fixation of the cannula induce a significant reduction in the blood-flow velocity.

Adult↗
PubMed1989

Thoracic epidural anaesthesia in patients with unstable angina pectoris.

The effect of high thoracic epidural anaesthesia with intermittent epidural bolus injections of bupivacaine (2.5 or 5 mg ml-1) was studied in 28 patients with unstable angina pectoris. The majority of the patients had a history of previous acute myocardial infarction(s) and/or angina pectoris and severe coronary artery disease. All patients were treated with nitroglycerin infusion for greater than 24 h and were included in the study if they had chest pain, not caused by acute myocardial infarction, at bed rest or recurrent anginal pain at rest greater than 2 days after infarction. 4.4 +/- 0.3 ml of bupivacaine induced a blockade of the upper seven sympathetic segments (Th1-7) for 98 +/- 9 min. Heart rate decreased significantly from 70 +/- 3 to 64 +/- 3 beats min-1 while blood pressure was unaffected by thoracic epidural anaesthesia. In 27 patients (96%) the anaesthesia induced complete analgesia. Nitroglycerin infusion was discontinued definitely within 3 h in 26 patients (93%) and pain was thereafter controlled by means of thoracic epidural anaesthesia as the sole treatment in 23 patients (82%) and as the major treatment in 25 patients (89%). Twenty-one patients (75%) were fully mobilized and stabilized. Treatment with thoracic epidural anaesthesia lasted for 6.0 +/- 1.1 days. The number of daily epidural injections decreased significantly with time from 2.7 +/- 0.3 the first day to 0.9 +/- 0.3 the fourth day (P less than 0.01, n = 19). Two patients developed acute myocardial infarction during the anaesthesia treatment period, and one of these patients died.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

Cannula thrombophlebitis: a study in volunteers comparing polytetrafluoroethylene, polyurethane, and polyamide-ether-elastomer cannulae.

Cannulae made of polytetrafluoroethylene (PTFE: n = 11), thermoplastic polyether-urethane (TPEU: n = 11), and a new test material, polyamide-ether-elastomer (XLON: n = 10) were inserted into the veins of the dorsum of the hand in 32 healthy volunteers (10 women and 22 men), 21-50 years old. The cannulae were intended to be left in place for 5 days. No infusion was given and the dressings were not exchanged. The resulting thrombophlebitis, defined as two or more of the symptoms pain, redness, oedema and hardness, was estimated on a scale which took into account the incidence, location, intensity, and duration of the symptoms. Except for one volunteer in the XLON group, all the volunteers developed thrombophlebitis, generally observed on the third day of cannulation, and being more frequent and intense over the cannulae (P less than 0.001) and at the tip (P less than 0.01) than at the insertion sites. Pain and oedema were, on the whole, the most frequent and severe symptoms during the period of indwelling. After withdrawal, hardness was the most intense, and together with pain, the most long-lasting (up to 10 days) symptom. The differences between the materials in thrombophlebitis incidence and intensity were statistically significant only when each symptom was analysed separately. Thus, the PTFE cannulae caused more pain and hardness (probably because of greater platelet adhesion and a relatively greater stiffness), while the TPEU and XLON cannulae produced more periphlebitis (redness and oedema), probably because of potentially irritant and antigenic substances leaking from them (polyurethane oligomers and polyamide/polyethyleneglycol oligomers).

Adult↗
PubMed1986

Estimation of central venous pressure by measurement of proximal axillary venous pressure using a "half-way" catheter.

The pressure in the proximal axillary vein (AVP) was compared with central venous pressure (CVP) in eight patients during and after elective abdominal surgery. Both pressures were recorded from soft, elastic, polyurethane catheters inserted in the basilic or cephalic veins ("half-way" catheters), punctured at the fossa cubiti (AVP), and via the right jugular vein (CVP). The AVP and CVP were recorded simultaneously using hydrostatic, conventional disposable venous pressure measurement sets. The measurements were performed during intermittent positive pressure ventilation with positive end-expiratory pressure from 0 to 7.5 cmH2O (0-0.74 kPa), as well as during spontaneous breathing. During both controlled and spontaneous respiration, small mean differences (0.2-1.0 cmH2O) (0.02-0.1 kPa), and a highly significant (P less than 0.001) positive correlation between CVP- and AVP-values were found. An increase of 1 cmH2O (0.10 kPa) in the CVP was associated with an increment of practically identical order (0.99-1.04 cmH2O) (0.10-0.11 kPa) in the AVP. The results suggest that monitoring of the AVP by a basilic "half-way" catheter produces diagnostic information similar to that from the measurement of the CVP from subclavian, external or internal jugular, as well as "long-way" brachial catheter, with no risk of the major mechanical complications which accompany the use of the latter catheters.

Adult↗
PubMed1986

Surface morphology of unused and used Hydromer-coated intravenous catheters.

Hydromer-coated polyurethane (Erythroflex) catheters, unused, or intravenously inserted for 2-20 days, were studied by scanning electron microscopy (SEM). Both unfixed and fixed (2% glutaraldehyde in phosphate buffer), and air-or critical-point dried (CPD) specimens were investigated. The catheter segments were sputter-coated with approx. 20 nm gold and studied at an accelerating voltage of 20 kV. The specimens were examined for surface depositions, thickness and structure of the Hydromer layers, and occurrence of adhering and embedded bacteria. The outer Hydromer layer showed, in the unused specimens, scratches and fissures, as well as adhering foreign bodies. In used specimens, the layer was swollen, with cracks (like "dried earth"), and, occasionally, amorphous substances and coccoid bacteria were seen adhering. Damage to the layer, or even its total disappearance was also noted in some specimens. The inner (luminal) Hydromer layer was, in unused specimens, clean and slightly wavy. In used catheters, it was thicker, possibly swollen, with small, isolated or agglomerated protrusions, like a "lunar landscape". Adhering platelets and amorphous substances were also occasionally seen. The results suggest that the Hydromer is a fragile material in both its dry and wet forms. Thus, the Hydromer-coated catheters should neither be stored in flexible packs, nor inserted by the Seldinger technique. The findings do not support the belief that the Hydromer-coating can prevent either thrombus formation, or intraluminal occlusion of the in-situ catheters.

Catheters, Indwelling↗
PubMed1985

"Half-way" venous catheters. II. Anatomoradiological basis.

In order to develop a "half-way" venous catheter for clinical use, anthropometric (n = 200), radiographic (n = 101), and phlebographic (n = 44) investigations were undertaken to determine the lengths, diameters, and morphology of the basilic and cephalic veins from fossa cubiti to the lateral edge of the first rib. The lengths of basilic and cephalic veins varied from 25 to 45 cm, exceeding 40 cm in approximately 5% of cases. Catheter lengths to be inserted were correlated ("r" = 0.6-0.7) with body heights, accurately estimated by 1/5 of the body height (cm) plus 2 cm for the basilic vein, and 4 cm for the cephalic vein. The cephalic veins have small proximal end diameters (mean = 6 mm), and present terminal arches of 2-3 cm. These are connected by a rich anastomotic network to the superficial cervical veins. The basilico-axillary courses are regular with gradually increasing diameters (mean = 16 mm), but in some observations, with the arms maximally abducted, the axillary veins presented accentuated folds. With these considerations, we recommend the insertion of the "half-way" catheters by basilic approach with the patient's arm in 90 degree abduction. The axillosubclavian length (mean = 18.5 cm) ensures wide limits for accurate placement of the "half-way" catheter tips when a basilic approach is used. Further, their large diameters (16-19 mm) make flotation of the soft catheters probable.

Adolescent↗
PubMed1985

"Half-way" venous catheters. III. Tip displacements with movements of the upper extremity.

Directions and sizes of displacement of "half-way" catheter tips with movements of the upper extremities were investigated in thoracic radiographs in 21 patients (10 women and 11 men), 28-88 years old. Ten catheters were inserted by basilic, and 11 by cephalic veins punctured at the fossa cubiti. Catheter tip positions were related to the lateral edge of the first rib. The tip position with the patient's arm in 90 degree abduction was considered as the reference point. Displacements caused by maximal flexion of the forearm, maximal adduction of the upper extremity, and maximal elevation of the brachium plus maximal flexion of the forearm were studied. With all movements and venous approaches there were significantly more medial than lateral displacements (P less than 0.001). The medial displacements varied from 0.2-5.0 cm, and the lateral ones from 0.5-1.8 cm. Location of the "half-way" catheter tips in the proximal axillary vein, at the lateral edge of the first rib, is recommended. As found previously, this may be obtained by inserting a catheter length representing 1/5 of the patient's height. Such a location inhibits harbouring of the "half-way" catheter tips in the jugular veins with movement in the upper extremities. Furthermore, estimation of central venous pressures by axillary venous pressures is not affected.

Adult↗
PubMed1985

"Half-way" venous catheters. IV. Clinical experience and thrombogenicity.

"Half-way", Secalon-Seldy, soft venous catheters, 40 cm long, were inserted by basilic (n = 90) and cephalic (n = 31) veins at the fossa cubiti in 121 patients (71 men and 50 women) aged between 19 and 88 years whose heights varied from 152-197 cm. The inserted catheter lengths approximated 1/5 of the patient's height. Sixty-five per cent of 106 radiologically investigated catheter tips were located proximally in the axillary veins, and 34% distally in the subclavian veins. The duration of catheterization varied from 1 to 44 (mean 9 +/- 7) days (means +/- 1 s.d.). Perfect function was recorded in 93 of 121 catheters. No serious, but some minor complications were registered such as temporary interruption of infusion flow with movements of the arm (n = 12), partial or total catheter occlusion (n = 16), leakage of the infusate at the insertion site (n = 1), and pain along the vein during infusion (n = 2). Five patients (4%) developed thrombophlebitis 2-.10 days after insertion. Pull out phlebographies at catheter withdrawal (4-35 days after insertion) were performed in 36 patients. Radiological thrombi were small and similar to those recorded in another 53 phlebographies of "long-way" brachial catheters of similar stiffness. Neither local infection nor episodes of sepsis were registered over a period of 1,081 catheter days. "Half-way" catheters proved able to take over all the functions of both peripheral and central venous catheters, lacking the frequent complications (phlebitis and infection) of the former, and the serious mechanical complications (pneumothorax, vein perforations, and injuries of the ductus thoracicus, nerves, arteries, and heart) of the latter.

Adult↗
PubMed1984

Material thrombogenicity in central venous catheterization III. A comparison between soft polyvinylchloride and soft polyurethane elastomer, long, antebrachial catheters.

Soft venous catheters, 36 made of polyurethane (PU) and 37 made of polyvinylchloride (PVC), were inserted in 73 patients via basilic and cephalic veins punctured at the cubital fossa, and compared regarding their thrombogenicity. The mean duration of catheterization was 12.5 days. Two patients with PU- and six patients with PVC-catheters developed clinical thrombophlebitis 4-36 days after insertion. The radiological thrombi were rather small with both PU- and PVC-catheters in both peripheral and central veins with no significant difference between the catheters. Also, the incidence of thrombosis and the rate of catheter occlusions were similar. The surface topography of the PVC-catheters was relatively smoother, but less uniform than that of the PU-catheters. Platelet adhesion in vitro to the catheter surfaces, expressed as ATP-concentration in relation to catheter area after contact with human blood, was relatively low with both catheters. The results suggest that soft PU- and PVC-catheters have a similar thrombogenicity.

Adolescent↗
PubMed1984

Dynamics of thrombophlebitis in central venous catheterization via basilic and cephalic veins.

The incidence distribution of thrombophlebitis after central catheterization via basilic and cephalic veins was investigated, using 227 catheters made of various plain or heparin-coated materials and with differing stiffness and surface structures. The platelet-adhesion stimulating properties were measured in vitro. Thrombophlebitis showed similar incidence patterns with all catheter types. The maximum incidence of venous reaction was found one to ten days after catheter insertion (central tendency 3-8 days with a peak at 5 days). After ten days the risk of thrombophlebitis fell significantly. The results supported the view that central venous catheters inserted via basilic or cephalic veins should not be withdrawn or exchanged as prophylaxis against thrombophlebitis, at any rate when long-term catheterization is intended. For conclusive comparisons between catheter materials regarding induction of clinically apparent thrombophlebitis, all the patients in the trial should be catheterized for ten days or more, unless symptoms of venous reaction arise earlier.

Adolescent↗
PubMed1983

Stiffness of central venous catheters.

Catheter stiffness has been suggested to be a principal factor in the thrombogenesis encountered after central venous cannulation. However, no data have been published to date about the stiffness of central venous catheters. A method for measuring catheter stiffness has been developed. The force needed to deflect a catheter tip 1.2 mm from a fastening point was measured with the help of a cantilever beam (Grass Model DA-7). Six different sections of each catheter were measured, and the final results expressed as an average of these. Twenty-seven central venous catheters made of silicone elastomer, polyurethane, polyvinylchloride, polyethylene and teflon were tested. The bending stiffness, EI (E = elastic modulus of the material, I = moment of inertia of catheter (a geometrical property)) was below 16 X 10(-6) Nm2 for all catheters made of silicone elastomer, polyvinylchloride and polyurethane. Polyethylene catheters were stiffer, but could be made softer by reduction of their diameters. Teflon catheters were up to 10 times stiffer than the catheters in the soft group. Heparinization and radioopacity of catheters do not significantly alter their bending stiffness. In a concomitant study the results indicate that there is a significantly lower incidence of thrombus formation in catheters with a bending stiffness below 16 X 10(-6) Nm2.

Catheterization↗
PubMed1983

Material thrombogenicity in central venous catheterization II. A comparison between plain silicone elastomer, and plain polyethylene, long, antebrachial catheters.

Central venous catheters of two types were inserted through basilic or cephalic veins punctured at the fossa cubiti in 61 patients: 39 soft silicone elastomer (S.E.) and 22 stiffer polyethylene (P.E.) catheters were compared regarding their thrombogenicity. Mean duration of catheterization was 6.5 days. Radiological thrombi in the peripheral and central veins visualized by phlebography were significantly smaller, and the incidence of the mural thrombi in the central veins significantly lower with the S.E. than with the P.E.-catheters, but the use of S.E.-catheters did not reduce the incidence of clinical thrombophlebitis in arm veins: 14 cases in the group with S.E. and four in that with P.E.-catheters. In both groups, the maximum incidence of clinical thrombophlebitis occurred 4-8 days after catheterization. Later, there seems to be a low risk for the appearance of clinical thrombophlebitis with both catheters. Neither the surface topography of the catheter materials, nor the platelet adhesion on their surfaces in contact with human blood in vitro offered conclusive arguments for interpretation of their thrombogenicity in vivo. Catheter stiffness seems to play an important role in inducing mural thrombus formation in central venous cannulation in man.

Adolescent↗
PubMed1982

Material thrombogenicity in central venous catheterization. I. A comparison between uncoated and heparin-coated, long antebrachial, polyethylene catheters.

In order to evaluate a new method of heparinization, uncoated (22) and heparin-coated (27) central venous polyethylene catheters were inserted in 49 patients via basilic and cephalic veins punctured at the fossa cubiti. The means duration of catheterization was 5.7 (1-11) days. One-third of the patients with heparin-coated catheters, and one sixth with uncoated catheters developed clinical thrombophlebitis, with a maximum incidence between 4 and 8 days after catheterization. A higher risk of developing thrombophlebitis in the first 4 days after catheterization was found in the patients with heparin-coated polyethylene catheters. After 8 days of catheterization, it seems that there is a lower risk of new cases of thrombophlebitis appearing both in patients with uncoated and those with heparin-coated polyethylene catheters. Radiological thrombosis, regardless of duration of catheterization and heparin-coating, was demonstrated in all 22 patients investigated by "pull-out" phlebography. The heparin-coating did not decrease the rate of thrombotic complications. Location of the catheter tip in subclavian veins was associated with a significantly higher incidence of large, parietal thrombi and catheter occlusion than when the tip was situated in anonymous veins, the superior vena cava, or the right atrium. Cannulation by heparin-coated, polyethylene tubing did not reduce the rate of catheter occlusion.

Adolescent↗
PubMed1981

Local discomfort and thrombophlebitis following intravenous injection of diazepam. A comparison between a glycoferol-water solution and a lipid emulsion.

Diazepam is frequently used for pre- and peroperative sedation. However, at i.v. injection local pain and thrombophlebitis are not uncommon, probably due to tissue irritancy of the various organic solvents necessary to keep diazepam in aqueous solution. In this study the incidence of local adverse effects following i.v. injection of Diazemuls, a new lipid emulsion formulation, was compared with that of Apozepam, a glycoferol-water solution. We found that the latter preparation caused local pain and thrombophlebitis as often as reported with propyleneglycol-phenylcarbinol-ethanol preparations (Stesolid, Valium) and in a statistically higher incidence that the lipid emulsion form, which therefore seems more suitable for intravenous use.

Adult↗