Injection Mode Research Articles

Clinical observation of regular intermittent epidural injection combined with different puncture points in suppressing breakthrough pain in labour analgesia

The aim of the current study was to evaluate the clinical effects of the regular intermittent epidural injection combined with different puncture points (RIEI-dPP) in suppressing breakthrough pain during a labour analgesia. A total of 90 primipara were randomly divided into three groups (n = 30): Group L2–3 (A), Group L3–4 (B) and Group L4–5 (C). The analgesic pump parameters were set as: impact dose 8 mL, locking time 15 minutes, background dose 0, and the additional impact dose 8 mL after each hour intermittence. The pain’s visual analogue scale (VAS), breakthrough pain, maximum block segment, modified Bromage score, labour duration and the neonatal Apgar score were recorded and compared. Compared with the pre-analgesia time, the VAS scores were found to be significantly decreased in the three groups (p < .05), but there were significant differences among the three groups (p > .05). During analgesia, the maximum block segment in Group C was more significantly reduced than in the other two groups (p > .05), but there was no significant difference in the breakthrough pain among the three groups (p > .05). The comparison of other indexes among the three groups showed there was no significant difference (p > .05). RIEI-dPP at L2–3, L3–4 and L4–5 during labour analgesia can effectively inhibit breakthrough pain.Impact StatementWhat is already known on this subject? According to human anatomical features, the injection speed and capacity are the prerequisite for obtaining the ideal block range. Experiments confirm that a more uniform and wider drug distribution can be achieved by epidural intermittent rapid infusion with higher injection pressure than a continuous infusion with low injection pressure. Compared with the continuous epidural administration mode, the regular intermittent epidural injection mode can better inhibit breakthrough pain with a lower amount of anaesthetic.What the results of this study add? Similar labour analgesic effects can be achieved by regular intermittent epidural injection mode with different puncture points.What the implications are of these findings for clinical practice and/or further research? Compared with a continuous infusion, a regular intermittent epidural injection can achieve a more uniform drug distribution in the epidural space, so the block range can be more extensive, which can not only reduce the amount of anaesthetic but also effectively reduce the incidence of breakthrough pain. However, the selection of an intervertebral puncture site still lacks a uniform standard. The outcomes of this study can directly verify that regular intermittent epidural injection at L2–3, L3–4 and L4–5 can effectively inhibit breakthrough pain and achieve good analgesic effects, so selecting the intervertebral space with clear anatomical structure positioning and easier puncture pathway can benefit a labour analgesia.

Field Effect in PbSnTe:In Films with Low Conductivity in the Mode of Injection from Contacts and Space-Charge Limitation of the Current

At T = 4.2 K, a strong change (up to 4 times) in the space-charge-limited current (SCLC) is observed for the first time at samples based on semi-insulating PbSnTe:In films grown by molecular-beam epitaxy on BaF2(111) substrates. The obtained results agree with experiments on the effect of treatment of the surface of PbSnTe:In films on the space-charge-limited current with a variation in the current to 103 times or more. At a qualitative level, the model is considered which assumes the substantial contribution of localized surface states to space charge formed in the mode of space-charge-limited current due to the injection of charge carriers from contacts.

Numerical simulation of pulsed gas-to-liquid injection modes using open source CFD software package OpenFoam

The paper is devoted to numerical simulation of the regimes of pulse outflow of various gases (air and argon) into a vertical pipe, filled with a liquid of different density (water and Rose alloy), implemented in the OpenFoam package. This problem has a wide range of technical applications, ranging from the simulation of emergency modes of liquid-metal nuclear reactor operation to the depressurization of underwater gas pipelines, the operation of ship equipment systems, etc. The satisfactory agreement of the results of numerical simulation with experimental data has been obtained.

Laboratory Evaluation of Different Modes of Supercritical Carbon Dioxide Miscible Flooding for Carbonate Rocks

Summary Field application of supercritical carbon dioxide (sc-CO2) miscible flooding continues to grow. Optimization of sc-CO2 injection during miscible-flooding modes represents one of the dominant factors affecting its performance in carbonate oil reservoirs. The main objective of this study was to investigate the effect of different modes of sc-CO2 miscible injection on oil recovery and injectivity in carbonate rocks. Several modes of sc-CO2 injection were investigated, including continuous CO2 miscible flooding, water-alternating-gas (WAG), and tapered-WAG injection. Five coreflooding experiments were conducted to evaluate oil recovery for different modes of sc-CO2 injection under reservoir conditions. Composite cores of 25-cm length from a specific, producing carbonate reservoir were used in the study. Both horizontal- and vertical-coreflooding experiments of continuous-sc-CO2-injection mode were performed to compare oil recovery and injectivity during sc-CO2 flooding. Horizontal-coreflooding experiments under WAG mode were performed at pore pressures of 3,200 and 3,800 psi. The experimental results indicate that tertiary oil recovery was influenced significantly by different sc-CO2-injection modes and the direction of displacement. Original oil in cores was recovered at 18.4 and 26.74% for horizontal and vertical experiments of continuous-sc-CO2-injection modes, respectively. In horizontal-WAG experiments with different pore pressures, higher oil recovery was observed at a pore pressure of 3,800 psi compared with 3,200 psi. The marginal increase in incremental oil recovery indicates that pressure increase beyond 3,200 psi will not have a significant effect. The injectivity of different sc-CO2-injection modes is reported in this paper.

Simulation of the penetration range distribution for low energy ions injected into plant seeds

In the present experiment on low-energy ions implanted into seeds, factors such as the unique microstructure of the seeds, the energy and injection mode of the ions, the step diameter and scattering angle of the ions after collision, and the collision energy loss between ions and atomic nuclei or electrons are considered. A modified model for ions implanted into seeds is established. The range distribution is simulated for vanadium, titanium, and iron ions (V+, Ti+, and Fe+) with different energies and injection modes implanted into peanut, cotton, and wheat seeds, using the FORTRAN programming language and Monte-Carlo method; the results are in good agreement with the experimental data. In addition, the model is used to estimate the range distribution for nitrogen, hydrogen, and argon ions (N+, H+, Ar+) implanted into peanut, cotton and wheat seeds.

Insight investigation of miscible SCCO2 Water Alternating Gas (WAG) injection performance in heterogeneous sandstone reservoirs

In this manuscript, we present the results of a systematic approach to investigate the impact of core scale heterogeneity on the efficiency of miscible CO2 water-alternating-gas (WAG) flooding performance. Both vertical (by layering two axially-cut half plugs with differing permeability) and horizontal (stacking two smaller core samples with differing permeability in series) heterogeneities are explored. In the layered or vertically heterogeneous sample, the permeability ratio (PR) defines the ratio between the permeability values of each half plug. Our special sample construction technique using either a thin impermeable Teflon sheet to prevent flow communication or a thin tissue to promote flow communication has enabled us to investigate the effect of crossflow between half plug on the performance of the WAG flood. For the stacked composite or the horizontally heterogeneous core samples, short cylindrical core segments were used each with a different permeability value. We have also investigated the effect of the EOR injection mode (i.e. secondary vs. tertiary) on our results. For this study, core flooding experiments were performed using n-C10, brine and CO2 at a temperature of 343 K and a pressure of 12.4 MPa.The results obtained for homogeneous, layered and composite samples indicate that CO2 WAG flood performs better in all cases and achieves the highest recovery factor (RF) when conducted under the secondary mode (e.g. homogeneous: 93.4%, layered: 74.0%, and composite: 90.9%) compared with the tertiary mode (e.g. homogeneous: 74.2%, layered: 64.1%, and composite: 71.3%). For the layered samples, it was found that the oil recovery decreases noticeably with an increase in the permeability ratio (PR). For instance, RFs of 93.4%, 90.1%, 78.8%, and 74.0% correspond to PRs of 1, 2.5, 5, and 12.5, respectively. In contrast to our previous findings with continuous CO2 flooding which showed that crossflow enhances recovery in layered samples, for this study using WAG, crossflow was found to negatively affect the RF. Such an outcome may be attributed to the conformance control achieved by WAG flooding which would be more pronounced in the case of non-communication layers (i.e. no cross flow). In other words, the higher oil recovery of WAG flooding in a non-communicating system may be due to the dominance of viscous forces and, to a lesser extent, the vanishing effect of gravity forces that tend to reduce sweep efficiency. The effect of composite heterogeneity on the RF was also investigated with the results showing that the permeability sequence along the length of a composite sample has a noticeable but more subtle impact on RF.

Primary breakup dynamics and spray characteristics of a rotary atomizer with radial-axial discharge channels

An experimental investigation of primary breakup dynamics and spray characteristics of a rotary atomizer with high aspect ratio radial-axial discharge channel is described. A high-resolution shadow imaging technique with pulsed backlight illumination was used for spray visualization. For the rotary atomizer with high aspect ratio discharge channel and radial-axial orientation, visualization showed the occurrence of Centripetal–Coriolis-induced stream-mode injection for all operating conditions. In this mode of injection, a crescent liquid film forms in the channel exit and issues from the orifice as a liquid column or a thin liquid sheet depending on atomizer operating conditions. It was found that the liquid Weber number value determines the state of the injected liquid stream (column or sheet) during the breakup process. The breakup process was studied with the variation of rotational speed and liquid volume flow rate. A morphological classification of the different modes of breakup is obtained from the flow visualizations. Four breakup modes have been observed for the present range of test parameters. These include Rayleigh, bag, stretched ligament, and shear breakup modes. These modes are separated by transitional regimes. The results suggest qualitative similarities between the primary breakup of the present rotary atomizer with a non-turbulent liquid jet and a fan like liquid sheet under a gas cross flow. The maximum liquid stream penetration height was measured for some operating conditions. It is concluded that this parameter is depend on the momentum flux ratio and liquid Weber number. To further evaluate features of the spray, the droplet size measurements have been conducted using the PDIA technique. The results indicate that there is a relatively strong correlation between the SMD values and liquid Weber number, while a properly non-dimensionalized droplet size is well correlated with the momentum flux ratio and Rossby number.

Induced breeding of endangered spiny eel (Mastacembelus armatus) using PG extract

Mastacembelus armatus is an important freshwater spiny eel of Bangladesh. The experiment was initiated to establish an induced breeding technique of the species with two induced breeding trials. In trial I, four different doses viz. 20, 40, 60 and 80mg PGkg-1 body weight of the fish were used to standardize the PG dose to ovulate the female M. armatus, and in trial II, the best dose identified in trial I was injected to fish once (whole dose) or twice with divided dose of PG at the rate of 30% and 70% at 6h interval to observe the effect of the mode of hormonal injection. Among the four doses applied in trial I, best result was obtained from 40mg PGkg-1 body weight in respect of ovulation rate (100%) of females and fertilization (93.00±2.00%) and hatching rates (58.30±3.50%) of eggs. In trial II, the females treated once (with the whole dose) or twice with divided dose of PG equally responded and no significant difference (p&gt;0.05) was observed between the modes of hormone injection in respect of ovulation rate of females and fertilization and hatching rates of eggs. As M. armatus is considered as endangered fish, this induced breeding technique will help to conserve the fish as well as to produce seed in commercial hatcheries.&#x0D; Progressive Agriculture 29 (3): 267-275, 2018

From Coreflooding and Scaled Physical Model Experiments to Field-Scale Enhanced Oil Recovery Evaluations: Comprehensive Review of the Gas-Assisted Gravity Drainage Process

The gas-assisted gravity drainage (GAGD) process has been suggested to improve oil recovery in both secondary and tertiary stages through immiscible and miscible injection modes. In contrast to con...

Effect of split injection on particle number (PN) emissions in GDI engine at fast-idle through integrated analysis of optics and mechanics

To reduce toxic engine emissions and meet the strict regulations, split injection has been adopted to optimize engine performance and fast-idle has been selected as the researching condition. Two sets of experiments have been conducted to investigate the effect of split injection on particulate number (PN) emissions at fast-idle. The first set is conducted in a constant volume vessel to get detailed spray characteristics, while the second is conducted in engine bench analyzing the effect of split injection on real engine PN emissions. Establishing direct connection from spray characteristics and real engine PN emissions is the main objective of this paper. Higher ambient temperature can reduce spray angle, while spray tip penetration is insensitive to experimental parameters. Long injection pulse width combined with short height of damper (HOD) will increase the possibility to impingement. Total PN concentration of four injection modes all decreases at first and then increases with increasing coolant temperature, and split injection can obviously reduce total PN to 50% from single injection. With increasing coolant temperature, accumulation mode particles all decrease while nucleation mode particles show different trends under four injection modes. In addition, the last injection within split injection has obvious influence on PN emissions.

Combination of field amplified sample injection and hydrophobic interaction electrokinetic chromatography (FASI-HIEKC) as a signal amplification method for the determination of selected macrocyclic antibiotics

In this study, a field amplified sample injection (FASI) and hydrophobic interaction electrokinetic chromatography (HIEKC) method has been developed for the separation of five macrolide antibiotics: spiramycin, ivermectin, tylosin, josamycin, rapamycin, and one ansamycin drug – rifamycin. By the manipulation of both the sample and separation buffer compositions, their pH values and molarity, a systematic approach has been achieved to maximize analyte differential electrophoretic mobility and signal amplification. The impact of the sample solution composition and the injection mode on the signal amplification effect of the six tested antibiotics was also investigated. Moreover, the influence of the injection of the sample and the water plug on the quantity, symmetry and height of the analyte signal was demonstrated. All the analytes were completely resolved in less than 8 min in an uncoated fused-silica capillary of 75 μm internal diameter (I.D.) x 50 cm length. The electrophoretic separations were performed in a 60% (v/v) acetonitrile and 20 mM phosphate electrolyte system (pH 7.1) with an applied voltage of 25 kV. The established method was validated and confirmed to be applicable for the determination of the active ingredients in a quality control analysis.

Stratification and mixing dynamics of helium in an air filled confined enclosure

Leakage of hydrogen during storage and transportation, coupled with its large flammability range, are vital challenges for its acceptability as a viable alternate fuel carrier. Leaks may happen in storage areas, enclosed/semi-enclosed spaces and transportation lines. In Nuclear Power Plants, hydrogen may get generated from metal-steam reaction during a Loss of Coolant Accident; this released hydrogen may eventually find its way in the closed containment space and pose as a potential hazard, due to possible deflagration or severe detonation. A clear understanding of mixing dynamics and associated transport mechanisms of hydrogen gas in such confined areas, which are already filled with atmospheric air, will lead to efficient mitigation strategies. In this paper, experiments, and supporting numerical calculations, have been conducted to observe the role of various parameters on stratification and mixing dynamics of helium (as a substitute for hydrogen) in a fully closed test section. Injection locations, volumetric Richardson number and amount of helium injected have been varied to see its effects on mixing and flow distribution during injection and post injection phases. The mechanism of mixing in injection phase changes with the location of injection; highest mixing is achieved when helium injection is from bottom of the test section. Also, as we increase the amount of helium in the test section, buoyancy significantly decreases the mixing time in post injection phase, especially in the bottom injection mode. The results clearly discern the interplay of buoyancy, inertia, and diffusional forces in stratification and mixing mechanisms in closed enclosures.

Enantioselective analysis of pheniramine in rat using large volume sample stacking or cation-selective exhaustive injection and sweeping coupled with cyclodextrin modified electrokinetic chromatography

For the aim of simultaneously performing the enantioseparation and determination of the trace enantiomers in plasma samples, enantioseparation by HPLC using five kinds of chiral stationary phases were initially investigated. But unfortunately, enantioseparation could not be detected in reversed mobile phase mode with all the five columns. For this reason, two simple, economical and highly efficient online preconcentration methods, large volume sample stacking and sweeping (LVSS-sweeping) and cation-selective exhaustive injection and sweeping (CSEI-sweeping) both followed by the cyclodextrin modified electrokinetic chromatography (CDEKC) were examined in the present work. Parameters affecting the enantioseparation and enhancement efficiency of these two injection modes were monitored in detail, and migration order of the two enantiomers was identified by circular dichroism (CD) and HPLC. Upon optimization, two enantiomers were best separated with the improvement of sensitivity reaching 160-fold and 4000-fold respectively for LVSS-sweeping and CSEI-sweeping comparing with the normal CDEKC separation. Then the optimal condition of CSEI-sweeping-CDEKC was validated and showed high sensitivity (10 ng/mL for lower limit of quantification, LLOQ), satisfactory accuracy (96.8–111.6%) and precision (relative standard deviation, RSD within 9.4%). This demonstrated it to be a suitable strategy for the rapid enantioselective determination and quantitative analysis of pheniramine enantiomers in plasma samples. Therefore, the method was further applied in the enantiomeric analysis of pheniramine in rat pharmacokinetics and plasma protein binding investigations. Stereoselectivity in pharmacokinetics as well as plasma protein binding were observed, suggesting that the stereoselective protein binding might be responsible for the stereoselectivity in pharmacokinetics.

Numerical investigation of dual-fuel injection timing on air-fuel mixing and combustion process in a novel natural gas-diesel rotary engine

This study aimed at further improving the combustion efficiency of the diesel rotary engine (DRE), and in this regard a novel natural gas-diesel rotary engine (NG-DRE) was numerically studied. Based on the experimental validated computational fluid dynamics (CFD) model, a 3D-dynamic numerical study of the NG-DRE was carried out by adopting NG port injection plus diesel direct injection mode. The influence of natural gas injection timing (NGIT) and diesel injection timing (DIT) on air-fuel mixing, combustion and emission characteristics were explored. Simulation results showed that NG-DRE performance was better than DRE. During the entire air-fuel mixing process, NG movement was easily affected by the vorticity density due to its good diffusion characteristics, however its influence on diesel movement was relatively minimal. At assisted ignition timing, NG concentrated at the rear of the combustion chamber, and diesel concentrated at the front and middle of the combustion chamber. Delaying NGIT and DIT, the mixture became more concentrated due to a shorter mixing time. Moreover, the delayed NGIT and DIT resulted in improvement of the pressure and combustion rate, while for a further delayed DIT the pressure was decreased due to the pressure negative work. Considering the engine power and emission performance, for dual-fuel injection schemes, 340°CA BTDC and 70°CA BTDC were the preferred application schemes for NG and diesel respectively. Their peak combustion pressure (Pmax) increased by 16.34% and 27.38% respectively, but due to the richer mixture, soot value increased by 0.023% and 0.054% and CO (carbon monoxide) value also increased by 0.026% and 0.039% respectively.

Efficient Photochemical Vapor Generation of Molybdenum for ICPMS Detection.

Photochemical vapor generation (PVG) of Mo was accomplished using a 19 W high-efficiency flow-through photoreactor operating in a flow injection mode using 30-50% (w/v) formic acid as a reaction medium. The generated volatile product (most probably molybdenum hexacarbonyl) was directed by an argon carrier gas to a plastic gas-liquid separator and introduced into the spray chamber of an inductively coupled plasma mass spectrometer for detection. Particular attention was paid to the determination of overall PVG efficiency relative to that for liquid nebulization. Utilizing a sample flow rate of 1.25 mL min-1, corresponding to an irradiation time of 38 s, PVG efficiencies in the range 46-66% were achieved. The efficiency could be further enhanced by the presence of mg L-1 added Fe3+ ions. A limit of detection of 1.2 ng L-1 and precision of 3% (RSD) at 250 ng L-1 were achieved. Interferences from inorganic anions likely to be encountered during analytical application to real samples (NO3-, Cl-, SO42-, NO2-, and ClO4-) were investigated in detail. The accuracy and applicability of this sensitive methodology was successfully verified by analysis of fresh water Standard Reference Material NIST 1643e, two seawater Certified Reference Materials (NASS-7 and CASS-6), and by analysis of two samples of commercial dietary supplements solubilized in formic acid.

Study on the Limit and Time of Separated Layer Injection of Polymer Flooding in Second-class Oil Layers

Separated Layer Injection is widely used as an effective means of development in oilfields and the limit and time of Separated Layer Injection has a great influence on the development effect. According to the achievement of the fine reservoir description of research area, theory model is established. According to the oil displacement plan and development status of Second-class Oil Layers, the polymer flooding parameters are designed. Theory models with different permeability differential are designed, with the range of 1-6. Each model is simulated in different injection mode and separated injection timing. From the variation of water cut, remaining oil distribution and increment value of recovery rate, simulation results show that separated layer injection of polymer flooding should be applied when permeability differential reached 2. The best time of separated layer injection is related to the intensity of injection of high permeability reservoirs and low permeability reservoir. When the high permeability and low permeability oil layers have the same injection strength, Separated layer injection should be applied earlier. In the process of polymer flooding, water injection rate should not be excessively restricted on control layer injection, and it should be ensured in order to maximize the use of thick layer potential.

Investigation of Injection- and Radiation-Thermal Processes in Thin Gate Dielectric Films of MIS Structures

In order to modify the gate dielectric of MIS structures we suggest to implement the injection-thermal treatment which consists in the high-field injection of electrons of set density into the thin dielectric film and the subsequent annealing of the structure. We investigate an influence of modes of the injection-thermal treatment onto the modification of MIS structures. We demonstrate that the processes of MIS structure modification taking place at the injection-thermal treatment in many respects are identical to the processes taking place at the radiation-thermal treatment. We study an influence of modes of the high-field electron injection into the gate dielectric of MIS structure onto densities of charge defects and the injection hardness of samples. Besides, we research an influence of doping of the silicone dioxide film by phosphorus onto the same characteristics.

The influence of fuel ignition quality and first injection proportion on gasoline compression ignition (GCI) combustion in a small-bore engine

The present study shows the distinctive role of first injection proportion and fuel ignition quality in controlling the first-injection mixture homogeneity and the second-injection charge premixing, respectively, in a single-cylinder automotive-size gasoline compression ignition (GCI) engine running on a double injection mode. The engine was operated at 2000 rpm and the indicated mean effective pressure (IMEP) of about 940 kPa. From many previous studies on homogeneous charge compression ignition (HCCI) engines, it is well known that the increased mixture homogeneity can reduce engine-out emissions of particulates and nitrogen oxides (NOx) while increased unburnt hydrocarbon (uHC) and carbon monoxide (CO) emissions become an issue. Also, many diesel combustion studies showed that the increased charge premixing causes the higher initial rate of heat release and thereby increasing engine efficiency at the expense of NOx emissions. In partially premixed charge GCI combustion engines implementing a near-BDC first injection and a near-TDC second injection, however, it is unclear how the overall mixture homogeneity and premixedness impact engine efficiency and engine-out emissions. In this study, both the first injection proportion and fuel ignition quality were varied considering their expected influence on premixed charge preparation. Specifically, conventional gasoline fuels with 91, 95, and 98 research octane number (RON) were tested for GCI combustion for various first injection proportions of 20–50%. For fixed combustion phasing conditions realised by the variations of the second injection timing, the results show that the increased first injection proportion causes a more stretched profile of the apparent heat release rate (aHRR) with a lower peak value due to the increased mixture homogeneity of the first-injection charge. This leads to increased engine efficiency as the heat release occurs for a longer period of time while the more homogeneous mixture causes reduced NOx emissions and combustion-induced noise. The increased mixture homogeneity, however, leads to increased uHC and CO emissions. In comparison, the decreased fuel ignition quality (or increased RON) at fixed mixture homogeneity of the first-injection charge results in higher aHRR and thereby increasing the engine efficiency, which is due to the increased charge premixedness of the second-injection fuel. Consequently, the NOx emissions and combustion-induced noise increase while the uHC/CO/smoke emissions become lower. Due to these compounding effects of first-injection mixture homogeneity and second-injection charge premixedness, it was found that the optimised GCI engine efficiency and emissions, for selected operating conditions and given engine geometry, are achieved at 40% first injection proportion and 95 RON fuel.

High-speed silicon modulators for the 2 μm wavelength band

The 2 μm wavelength band has become a promising candidate to be the next communication window. We demonstrate high-speed modulators based on a 220 nm silicon-on-insulator platform working at a wavelength of 1950 nm, using the free carrier plasma dispersion effect in silicon. A Mach–Zehnder interferometer modulator and a microring modulator have been characterized. At 1950 nm, the carrier-depletion modulator operates at a data rate of 20 Gbit/s with an extinction ratio of 5.8 dB and insertion loss of 13 dB. The modulation efficiency (V π ·L π ) is 2.68 V·cm at 4 V reverse bias. The device operation is broadband, and we also characterize its performance at 1550 nm. At 1550 nm, an open eye is obtained at 30 Gbit/s. The difference in bandwidth is caused by the bandwidth limit of the 2 μm measurement setup. We also show a ring modulator paired with a low power integrated driver working in hybrid carrier depletion and injection mode at a data rate of 3 Gbit/s with power consumption of 2.38 pJ/bit in the 2 μm wavelength range. This work is a proof of principle demonstration and paves a route toward a full silicon-based transceiver in the 2 μm window.

EXTERNAL ILIAC ARTERY LIGATION AND LOCAL DEBRIDEMENT. A SAFE TREATMENT OPTION FOR INFECTED FEMORAL ARTERY PSEUDOANEURYSM IN INTRAVENOUS DRUG ABUSERS

Introduction: “Mycotic aneurysms are defined as a localized, irreversible dilationof an artery due to destruction of the vessel wall by infection.” Intravenous (IV) drug abuse isan increasing social and health problem. Repeated punctures under septic conditions alongwith needle sharing habits among IV drug abusers result in various vascular complications.In addition, patients who present with these complications frequently have viral infections,which are hazardous to healthcare workers. Objectives: With these existing controversies ofoptimal surgical management of infected femoral artery pseudo aneurysm, we reviewed oursurgical technique used for their treatment and their clinical outcome, in a population of IVdrug abusers of Rahim Yar Khan. Study Design: Retrospective, descriptive study. Setting:Sheikh Zayed Medical College/ Hospital Rahim Yar Khan. Period: 2 years from 1-1-2015 to 31-12-2016. Material & Methods: Total 10 patients were included in this study. All patients weremanaged and operated in emergency ward. In all the patients we performed first external iliacligation and then excision of the sac and debridement of the wound. The protocol of this studyhas been approved by the ethical committee of the hospital. Results: In this 2 years study,10 patients were managed. Mean age was 22.5 years and age range from 18-28 years. Allpatients were young males and belong to low socioeconomic status. The duration of IV drugabuse was 2-3 years. A self-injection was the commonest mode of injection. All the infectedfemoral pseudo aneurysms were on the right side. 5 patients were hepatitis C virus (HCV) +veand 4 patients were hepatitis B surface antigen (HbsAg) positive. Only one patient was humanimmunodeficiency virus (HIV) positive. Five patients presented with oozing pulsating mass and5 patients with infected pulsatile mass. Right leg was survived in all the patients. There was noamputation. Conclusion: Ligation of the external iliac artery first then excision and debridementof the infected femoral artery pseudo aneurysms seems to be a safe procedure in IV drugabusers with low morbidity and no mortality. There was no amputation of the limb.