Small Diameter Needles Research Articles

Needles used for spinal anesthesia

Since the discovery of spinal anesthesia in 1885 by J Leonard Corning, spinal needles have been modified to simplify their use and minimize complications. Needle design variables, such as diameter, tip design and orifice location, have been altered to enable rapid flow of cerebral spinal fluid (CSF) and injected medications, yet simultaneously limit dural trauma and loss of CSF. CSF loss can result in a severe postdural puncture headache (PDPH). Blunt pencil-point tip needles have been observed to cause a lower incidence of PDPH than similar sized sharp, cutting tip needles. Smaller diameter needles are also associated with a lower incidence of PDPH. A recent alteration in spinal needles is not to the needle per se, but rather the microcatheters placed through them; currently used in Europe, such catheters are again being evaluated in the USA. Further advancements in spinal needles will most likely involve some of the design elements previously altered, as well as new features not yet recognized as important at this time.

Apical Pressures Developed by Needles for Canal Irrigation

Drying instrumented canals with pressurized air may result in patient morbidity or even fatality. Low pressure and side vent needles have been suggested to lessen the danger. This study observed apical pressures from different needles inserted deeply into small round and ovoid canals as instrumentation progressed. Low-pressure (5 psi) air was injected through the needles, and apical pressures were recorded after each instrument. Pressures varied greatly within each test group. Generalities that can be drawn are that binding the needle within the canal gives higher pressures than with the needle slightly short of binding and that pressures were higher with apexes instrumented to size 30 and higher. With the needle tightly bound, neither needle size, needle design, nor canal shape resulted in statistically significant mean pressure differences. With the needle slightly withdrawn, larger bore needles gave higher pressures than small diameter needles. Caution is advised with the clinical use of pressurized air in the drying of root canals.

Post-dural puncture related complications after diagnostic lumbar puncture, myelography and spinal anaesthesia.

This study was conducted to investigate complications after dural puncture. A 15 months' prospective observation study of routine clinical practice with dural puncture at a university hospital was conducted. Quincke spinal needles 0.90 to 1.0 mm O.D. (20-19 g) were used for diagnostic lumbar puncture, 0.70 mm O.D. (22 g) for myelography and 0.40 to 0.50 mm O.D. (27-25 g) for spinal anaesthesia. A questionnaire about post-puncture discomfort was given to the patients, to be returned after 1 week. Of 679 questionnaires 537 (79.1%) were returned. Discomfort was experienced by 53.8% of the patients, most often after diagnostic lumbar puncture and myelography. The difference in incidence of headache after diagnostic lumbar puncture and myelography compared with spinal anaesthesia were 27.9% (95% CI: 18.6 to 37.2) and 18.3% (95% CI: 9.1 to 27.5). Small diameter and atraumatic spinal needles will reduce patients' discomfort after dural puncture.

Sampling Arterial Blood With a Fine Needle

Radial arterial puncture for obtaining blood samples is a painful procedure that justifies the use of prior local anesthesia in the puncture area to significantly reduce pain. 1 Giner J. Casan P. Belda J. et al. Pain during arterial puncture. Chest. 1996; 110: 1443-1445 Abstract Full Text Full Text PDF PubMed Scopus (89) Google Scholar Providing local anesthesia, however, supposes piercing twice, once for anesthetic infiltration and once again for arterial puncture. Some authors 2 Sabin S. Taylor J.R. Kaplan A.I. Clinical experience using a small-gauge needle for arterial puncture. Chest. 1976; 69: 437-439 Crossref PubMed Scopus (11) Google Scholar have suggested that performing the puncture with a smaller diameter needle would reduce pain, making anesthesia unnecessary and at the same time shortening the procedure.

Towards reducing the trauma of direct intracompartmental pressure measurement for children: an in vitro assessment of small-diameter needles

Towards reducing the trauma of direct intracompartmental pressure measurement for children: an in vitro assessment of small-diameter needles

Towards reducing the trauma of direct intracompartmental pressure measurement for children: an in vitro assessment of small-diameter needles

Direct intracompartmental pressure (ICP) measurement in children is an important investigation, the use of which may be inhibited by the invasive nature of the procedure and the large 18-gauge (G) needles that have hitherto been recommended. These large needles contribute to patient, parental, and physician anxiety. This study compares ICP measurements using needles of different lengths and port configuration, ranging from 18 to 25 G, against the "gold standard" 18 G, long, double-ported needle. All except the 18 G long, single-ported needle had limits of agreement within 3 mm Hg of the gold-standard needle. The results indicate that needle manometry can confidently be performed using small needles, and that the addition of a side-port is unnecessary in needles of small volume.

Effect of aspirating needle calibre on outcome of in-vitro fertilization

Thirty patients with intact ovaries undergoing ultrasound-guided transvaginal oocyte retrieval for in-vitro fertilization treatment had their ovaries randomized for follicular aspiration with small and large aspiration needles while under mild sedation. Collections using smaller diameter needles had no significant effect upon the number of oocytes collected per follicle aspirated, or on the subsequent fertilizing capacity of those oocytes. There was significant reduction in pain perceived by the patient when the smaller needle was used during the collection.

A helium gas probe for use in cryosurgery

The design and testing of a prototype cryosurgical probe utilizing helium gas precooled with liquid nitrogen are described. An 8-mm-diameter probe produced an ice ball with a diameter of 28 mm after 10 min freezing using a helium gas flow rate of 42 liter/min. This indicated a surface heat transfer coefficient of 0.34 W/cm 2 °K and temperature of −138 °C at the probe tip. Improved performance figures can be achieved using higher gas pressures and flow rates. A helium gas flow system schematic for use with this new type of cryoprobe is also presented. It is claimed that this system will overcome the problems of developing both multiple-tipped probes and small-diameter needle probes for use in cryoanalgesia.

Experimental study of viscoelastic effectives in a cylinder-plane lubricated contact

This experimental study is related to the flow between a stationary small diameter needle and a moving drum of much larger diameter, seen as a moving plane. Our visualisation experimental set-up adds new results regarding the flow behaviour of a polymer solution. This flow is compared to that of a Newtonian fluid used under the same kinematic conditions. Important differences between Newtonian and polymeric flows concern mainly streamlines, stagnation point positions, and reverse flow. A second experimental set-up enabled us to obtain normal stress profiles along the needle wall and the flow rate through the gap. Reslts related to Newtonian flows are compared to the well-known analytical solutions for a bidimensional laminar flow.

Determination of mitochondrial/cytosolic metabolite gradients in isolated rat liver cells by cell disruption

A new technique is described for determining the distribution of metabolites between the cytosol and mitochondria. Rapid lysis of the cell plasma membrane is obtained by forcing isolated liver cells under high pressure through a small diameter needle. The cells, after disruption by the shearing forces generated during the turbulent flow through the needle, are exposed to mitochondrial anion transport inhibitors to prevent efflux of mitochondrial metabolites. Maximal release of cytosolic metabolites was obtained when release of lactate dehydrogenase was greater than 70%, which corresponded with minimal release of mitochondrial enzymes (5–9%). A measured Reynolds number between 7600 and 8000 was indicative of optimal disruption. Mitochondria in the disrupted cells were still functional, as shown by the ability of ADP to stimulate respiration when glutamate plus malate were provided as substrates. Measurement of the subcellular volumes yielded values of 2.0 and 0.2 ml/g dry wt, respectively, for the cytosol and mitochondria. Calculation of the mitochondrial ΔpH (pH in-pH out) in the isolated liver cell based on 22 individual measurements of mitochondria/cytosol gradients for citrate, isocitrate, α-ketoglutarate, malate, glutamate, and pyruvate yielded a value of 0.41 ±0.03. The excellent relationship of these gradients to a common ΔpH lends credence to the technique. Cytosolic and mitochondrial ATP ADP ratios were similar in liver cells isolated from starved and fed rats. Fed rat liver cells, however, had a higher cytosolic adenine nucleotide content (16.8 μmol/g dry wt) than those from starved rats (14.5 μmol/ g dry wt) whereas the mitochondrial content was the same (16 nmol/mg of mitochondrial protein). Data obtained by the disruption technique are compared with other previously published data obtained using either digitonin treatment of isolated hepatocytes or nonaqueous solvent extraction of lyophilized freeze-clamped perfused livers.

Bile pleuritis: another complication of percutaneous liver biopsy.

There has been a marked decrease in morbidity and mortality from hepatic-needle biopsy in recent years. Despite this, cases are being reported which suggest that almost the entire spectrum of traumatic liver injury may occur because of biopsy. In this patient with obstructive jaundice, bile pleuritis requiring surgical intervention followed liver biopsy. High-risk liver biopsies should be performed by experienced personnel using a small-diameter Menghini needle.

A hydrodynamic curiosity: The salt oscillator

Abstract If a vertically oriented hypodermic syringe with the plunger removed is filled with salt water and partially submerged in a beaker of fresh water, then under the proper conditions, the system develops finite amplitude oscillations. These oscillations appear as a downward jet of salt water, followed by an upward jet of fresh water, and so on for many cycles. The geometry of the syringe determines the period of the oscillations: a long, small diameter needle yields a slow, viscous flow; a short, large diameter needle yields fast inviscid pumping. Theoretically, a time‐dependent Hagen‐Poiseuille pipe flow model describes the oscillations; furthermore, the oscillations can be divided into two modes, depending on whether viscous or non‐linear damping predominates. When viscous damping predominates, the geometry of the syringe determines the period of the oscillations, which are independent of the density difference ?ρ except as the viscosity varies with density. When non‐linear damping predominates, t...