Preclinical studies of non-stick thin film metallic glass-coated syringe needles.

Our objective in this study was to determine the biocompatibility and hemocompatibility of thin film metallic glass (TFMG) and its potential use in hypodermic needles for intramuscular or intravenous injection. Mouse and rabbit models were employed under approval from the Institutional Animal Care and Use Committee (n = 5/group, two groups in total for both animal models). Platelet-rich plasma (PRP) was collected from the whole blood of rabbits (ear vein) without anti-coagulant for use in in vitro coagulation tests. Histological analysis and optical microscopy were used to assess the endothelial structure of the inner lining of veins after being punctured with needles and detained for 3 days. Histological analysis of ear vein sections revealed that the extent of endothelial damage after puncturing with a TFMG-coated needle was 33% less than that produced by bare needles. Our results confirm that the deposition of a thin TFMG layer (e.g., Zr53Cu33Al9Ta5) on the surface of hypodermic needle can have remarkably clinical benefits, including anti-adhesion, reduced invasion, and minimal endothelial damage. Our results also confirm the good biocompatibility and hemocompatibility of the TFMG coatings.

Técnica de inyección intravenosa push-aspire-push para la administración no dolorosa de medicación. Estudio piloto sobre su efectividad / Push-aspire-push intravenous injection technique for non-paining medication administration. Pilot study on its effectiveness

Una de las funciones de quienes nos dedicamos a la anestesia es tratar el dolor en los pacientes. En consecuencia, hay que evitar que la administración de medicación en la inducción anestésica lo provoque. De los distintos modos de administrar medicación intravenosa, en este estudio sólo haremos referencia a la administración mediante jeringa. A partir de la técnica Push-Stop-Push y con una determinada velocidad de administración, se ha diseñado una nueva técnica de administración intravenosa a la que se ha llamado «Push-Aspire-Push». Esta técnica consiste en inyectar un cierto volumen de medicamento, aspirar y volver a inyectar otro volumen; todo ello en un tiempo determinado. Al administrar la medicación de esta manera, se consigue que esté más tiempo en contacto con la pared vascular de la zona de punción, en la medida en que se crean turbulencias en el lecho. De este modo, la medicación analgésica y/o anestésica local podrá hacer más efecto en la zona de inserción del catéter. Se ha podido verificar que con la técnica Push-Aspire-Push ha desaparecido, independientemente del calibre de catéter o zona de punción, el dolor en los pacientes estudiados, sin que haya aumentado el tiempo de inducción anestésica ni se hayan utilizado técnicas molestas

One of the functions of those who dedicate ourselves to anesthesia is to treat pain in patients. Therefore, it is necessary to avoid that the administration of medication in anesthetic induction causes it. Of the different ways of administering an intravenous medication, we are only going to refer to administration by syringe. Based on the Push-Stop-Push technique and with a certain administration speed, a new intravenous administration technique has been designed which has been called «Push-Aspire-Push». This technique consists of injecting a certain volume of medication, aspirating and re-injecting another volume; all this in a certain time. By administering the medication in this way, we achieve that it is in longer contact with the vascular wall of the puncture area, as certain turbulences are created in the bed. In this way, the analgesic and / or local anesthetic medication may have more effect in the catheter insertion area. It has been verified that, with the Push-Aspire-Push technique, pain has disappeared, regardless of the catheter size or puncture site, in the patients studied, without increasing the anesthetic induction time or using annoying techniques

Is it safe to inject contrast through the side arm of an introducer sheath? An in vitro study.

PURPOSE: Occasionally, a patient requiring computed tomography (CT) with poor venous access or in an unstable condition may have a sheath as their only form of IV access. Many institutions prohibit contrast power injection through the side ports, for concern for rupture. We hypothesize that under conditions encountered in CT scanning, the side arm of the sheath introducer is safe for power injection of contrast material. METHODS: In this in vitro study, we injected contrast at different flow rates varying from 2 to 8 ml/s, through the side port of the sheath. Time-pressure graphs were obtained for each injection from the injector display. The assembly was observed for any signs of leakage or material failure. RESULTS: There was not a single event of leak, rupture, or displacement. Maximum pressures were within the range of conventional contrast administrations. CONCLUSION: This study suggests that iodinated contrast can safely be injected through the side port of a venous sheath.

Reducing the incidence of venous air embolism in contrast-enhanced CT angiography using preflushing of the power injector.

AIM: To evaluate whether preflushing before connecting a power injector to a patient's catheter reduces the incidence of venous air embolism (VAE) in contrast-enhanced computed tomography (CT) angiography (CTA). MATERIALS AND METHODS: With the approval from the local ethics committee, consecutive patients were divided randomly into a control group and a preflushing group and underwent CTA from June to November 2017. The control group underwent the conventional injection procedure. In the preflushing group, the injector tubes were flushed at high speed (10 ml/s) with saline before being connected to the patients' indwelling catheters. The locations, number, and sizes of VAE were analysed. The difference in the incidence of VAE between the two groups was compared. RESULTS: A total of 4,900 adults (control/preflushing, 2,190/2,710) were included and 228 (4.65%) patients were found to have 318 VAEs (285 bubbles and 33 gas-liquid plane VAEs). The incidence of VAE in the preflushing group (3.21%) was lower than that in the control group (6.44%); a similar trend was observed for multiple VAEs (p<0.05). VAEs occurred in the following locations from high to low frequency: right atrium>pulmonary artery trunk>superior vena cava>right ventricle>left brachial vein>right brachial vein. There was no significant difference in the location, shape, or diameters (p=0.19) of VAEs between the two groups. CONCLUSIONS: The proposed preflushing procedure is simple yet effective in reducing the incidence of VAE by 50.16% in patients with CTA, thus improving safety during power injection.

Association of the incidence of venous air embolism on coronary computed tomography angiography with the intravenous access route preparation process.

Venous air embolism (VAE) can be observed in the right heart system on contrast-enhanced computed tomography (CT), following injection of contrast media with a power injector system. Although most VAEs are mostly asymptomatic, they may result in paradoxical air embolism (PAE).To evaluate whether the incidence of VAE on coronary CT angiography is associated with the process of preparation of the intravenous access route.We retrospectively evaluated 692 coronary CT examinations at 3 institutions. Trained CT nurses placed an intravenous cannula in the forearm. Tubes connected to the cannula were prepared in the following ways: A, using an interposed three-way cock and a 20-mL syringe filled with normal saline to collect air contamination in the tube; B, through direct connection to the power injector system without the interposed 3-way cock; and C, using an interposed three-way cock and a 100-mL normal saline drip infusion bottle system to keep the tube patent. The incidence and location of VAE and preparation of intravenous injection were assessed.The overall incidence of VAE was 55.3% (383/692), most frequently observed in the right atrium (81.5%, 312/383). Its incidence varied significantly across the 3 techniques (A: 21.6% (35/162), B: 63.2% (237/375) and C: 71.6% (111/155); P < .001). No patient demonstrated any symptom associated with VAE.Using a 3-way cock with syringe demonstrated the lowest incidence of VAE on coronary CT angiography. It is thus recommended to reduce potential complication risks related to intravenous contrast media injection.

Heparin vs. Normal Saline Locking for Prevention of Catheter Occlusion.

Editor's note: This is a summary of a nursing care-related systematic review from the Cochrane Library. For more information, see http://nursingcare.cochrane.org.

Piston-Based vs Peristaltic Pump-Based CT Injector Systems.

PURPOSE: To compare the fluid delivery performance of 2 different technologies for administration of iodinated contrast media in computed tomography (CT). METHODS: The maximum achievable flow rate and the steady-state flow rate variance of a piston-based contrast media injector system (Stellant MP, MEDRAD) was compared with peristaltic pump-based injector systems (CT motion, Ulrich Medical; CT Exprès, Bracco). The contrast media iopromide (Ultravist) and iopamidol (Isovue) were used at 2 concentrations each (300 and 370 mg I/mL) and 3 catheter sizes (18, 20, and 22 G) to test the injector performance. RESULTS: Average maximum achievable flow rates for room temperature iopromide (370 mg I/mL) using a 20 G catheter were 7.6, 7.1, and 4.8 mL per second for the Stellant MP injector, CT motion injector, and CT Exprès injector, respectively. The Stellant MP injector achieved significantly higher flow rates compared to the CT Exprès injector for all catheter sizes tested (P<.001). Higher flow rates also were observed for the Stellant MP injector compared to the CT motion injector, with 20 G and 22 G catheters (P<.001). The Stellant MP injector featured a constant steady-state flow rate (variance<0.04 mL/s), whereas the other systems injected in a pulsatile fashion, with significantly greater variance (P<.001). DISCUSSION: To the authors' knowledge, this is the first reported laboratory study providing preliminary evidence of differences between the fluid delivery performance of CT injection systems. Additional investigations using a dedicated flow phantom simulating human physiological flow parameters should be conducted, and depending on the results, a clinical study could assess the effect on image quality. CONCLUSION: The piston-based injector demonstrated higher maximum achievable flow rates and more consistent steady-state flow when compared to peristaltic pump-based injectors.

The mask or the needle? Which induction should we go for?

PURPOSE OF REVIEW: This review summarizes the current evidence available to guide anaesthetists along the decision-making process between inhalational and intravenous anaesthesia when caring for paediatric patients. RECENT FINDINGS: A recent large randomized controlled trial in children with risk factors demonstrated a significant benefit of intravenous induction over inhalational induction with regards to respiratory adverse events. This difference is particularly pronounced in those with respiratory symptoms. SUMMARY: For children scheduled for elective surgery, intravenous induction has significant advantages with regards to reduced respiratory adverse events and for less postoperative behavioural disturbances, it may be associated with more anxiety at the time of induction. The anaesthetist in charge of the patient needs to weigh up the balance between the clinical risk of respiratory adverse events, the 'veins on offer', the level of anxiety and previous experiences of the child and his/her parents.

A Comparison of Error Rates Between Intravenous Push Methods: A Prospective, Multisite, Observational Study.

OBJECTIVES: Current literature estimates the error rate associated with the preparation and administration of all intravenous (IV) medications to be 9.4% to 97.7% worldwide. This study aims to compare the number of observed medication preparation and administration errors between the only commercially available ready-to-administer product (Simplist) and IV push traditional practice, including a cartridge-based syringe system (Carpuject) and vials and syringes. METHODS: A prospective, multisite, observational study was conducted in 3 health systems in various states within the United States between December 2015 and March 2016 to observe IV push medication preparation and administration. Researchers observed a ready-to-administer product and IV push traditional practice using a validated observational method and a modified data collection sheet. All observations were reconciled to the original medication order to determine if any errors occurred. RESULTS: Researchers collected 329 observations (ready to administer = 102; traditional practice = 227) and observed 260 errors (ready to administer = 25; traditional practice = 235). The overall observed error rate for ready-to-administer products was 2.5%, and the observed error rate for IV push traditional practice was 10.4%. CONCLUSIONS: The ready-to-administer group demonstrated a statistically significant lower observed error rate, suggesting that use of this product is associated with fewer observed preparation and administration errors in the clinical setting. Future studies should be completed to determine the potential for patient harm associated with these errors and improve clinical practice because it relates to the safe administration of IV push medications.

[The Efficacy of Near-Infrared Devices in Facilitating Peripheral Intravenous Access in Children: A Systematic Review and Subgroup Meta-Analysis].

BACKGROUND: Peripheral intravenous access is a common and invasive procedure that is performed in pediatric clinical settings. Children often have difficult intravenous-access problems that may not only increase staff stress but also affect the timeliness of immediate treatments. PURPOSE: To determine the efficacy of near-infrared devices in facilitating peripheral intravenous access in children, using a systematic review and meta-analysis. METHODS: Six databases, namely the Index to Taiwan Periodical Literature System, Airiti Library, CINAHL, Cochrane Library, PubMed/MEDLINE, and ProQuest were searched for related articles that were published between the earliest year available and February 2017. The search was limited to studies on populations of children that used either a randomized controlled trial or controlled clinical trial approach and used the key words "near-infrared devices" AND "peripheral intravenous access." The 12 articles that met these criteria were included in the analysis. The Cochrane Collaboration bias assessment tool was used to assess the methodological quality. In addition, RevMan 5.3.5 software was used to conduct the meta-analysis. RESULTS: The near-infrared devices did not significantly improve the first-attempt success rate, number of attempts, or the procedural time of peripheral intravenous access in children. However, the subgroup analysis of difficult intravenous-access factors revealed a significant improvement in the first-attempt success rate of children with difficult intravenous access scores (OR = 1.83, p = .03). CONCLUSIONS / IMPLICATIONS FOR PRACTICE: Near-infrared devices may improve the first-attempt success rate in children with difficult intravenous access by allowing healthcare professionals to visualize the peripheral veins. Therefore, we suggest that the difficult intravenous-access score be used as a screening tool to suggest when to apply near-infrared devices to children with difficult peripheral intravenous access in order to maximize efficacy of treatment.

Selection of peripheral intravenous catheters with 24-gauge side-holes versus those with 22-gauge end-hole for MDCT: A prospective randomized study.

PURPOSE: To compare the 24-gauge side-holes catheter and conventional 22-gauge end-hole catheter in terms of safety, injection pressure, and contrast enhancement on multi-detector computed tomography (MDCT). MATERIALS & METHODS: In a randomized single-center study, 180 patients were randomized to either the 24-gauge side-holes catheter or the 22-gauge end-hole catheter groups. The primary endpoint was safety during intravenous administration of contrast material for MDCT, using a non-inferiority analysis (lower limit 95% CI greater than -10% non-inferiority margin for the group difference). The secondary endpoints were injection pressure and contrast enhancement. RESULTS: A total of 174 patients were analyzed for safety during intravenous contrast material administration for MDCT. The overall extravasation rate was 1.1% (2/174 patients); 1 (1.2%) minor episode occurred in the 24-gauge side-holes catheter group and 1 (1.1%) in the 22-gauge end-hole catheter group (difference: 0.1%, 95% CI: -3.17% to 3.28%, non-inferiority P=1). The mean maximum pressure was higher with the 24-gauge side-holes catheter than with the 22-gauge end-hole catheter (8.16±0.95kg/cm2 vs. 4.79±0.63kg/cm2, P<0.001). The mean contrast enhancement of the abdominal aorta, celiac artery, superior mesenteric artery, and pancreatic parenchyma in the two groups were not significantly different. CONCLUSION: In conclusion, our study showed that the 24-gauge side-holes catheter is safe and suitable for delivering iodine with a concentration of 300mg/mL at a flow-rate of 3mL/s, and it may contribute to the care of some patients, such as patients who have fragile and small veins. (Trial registration: UMIN000023727).

Comparison of Mechanical Versus Hand Administration of IV Contrast Agents for Pediatric Pulmonary CT Angiography.

OBJECTIVE: The purpose of this study was to assess the difference between mechanical versus hand administration of IV contrast agents on the diagnostic quality of pediatric pulmonary CT angiography (CTA). MATERIALS AND METHODS: A retrospective review of the medical records was performed to detect pediatric patients (≤ 18 years) with pulmonary CTA performed between September 2012 and March 2015. Patients were placed into two cohorts on the basis of the method of contrast administration (mechanical vs hand). Additional information obtained included IV size or gauge, IV site, amount and type of contrast agent administered, and rate of administration (mL/s). The quality of the CT images was independently evaluated by two pediatric radiologists using a qualitative 4-point visual assessment scale and quantitatively with attenuation (HU). An ANOVA controlling for age compared the contrast enhancement in the central pulmonary arteries between the cohorts. RESULTS: One hundred forty-eight consecutive pediatric patients (71 boys and 77 girls; mean age, 11.1 years; age range, 8 days-17.9 years) were identified between September 2012 and March 2015. Mechanical administration of contrast material was performed in 117 patients (79.1%; mean age [± SD], 13.7 ± 3.7 years), and hand administration of contrast material was performed in 31 patients (20.9%; mean age, 1.6 ± 1.8 years). After adjusting for age, the degree of enhancement within the pulmonary arteries was not statistically different between the two IV contrast administration methods at the main pulmonary artery (mechanical vs hand administration: mean attenuation, 310 ± 128 vs 338 ± 142 HU, respectively, p = 0.505), right pulmonary artery (305 ± 124 vs 329 ± 146 HU, p = 0.556), and left pulmonary artery (303 ± 125 vs 340 ± 151 HU, p = 0.349). CONCLUSION: It is possible to perform diagnostic-quality pulmonary CTA for the assessment of the central pulmonary arteries with hand administration of IV contrast material in pediatric patients with small-gauge IV catheters.

Physical compatibility of ceftolozane-tazobactam with selected i.v. drugs during simulated Y-site administration.

PURPOSE: Results of a study to examine the physical compatibility of ceftolozane-tazobactam with common i.v. medications during simulated Y-site administration are presented. METHODS: Ceftolozane-tazobactam was reconstituted according to manufacturer recommendations and diluted with 0.9% sodium chloride or 5% dextrose to solutions containing 15 mg (10 mg of ceftolozane and 5 mg of tazobactam)/mL. All other i.v. drugs were prepared according to manufacturer recommendations and diluted with 0.9% sodium chloride or 5% dextrose to standard concentrations used clinically. Y-site administration was simulated by mixing ceftolozane-tazobactam solution with each tested drug solution at a 1:1 ratio. Solutions were inspected for visual, turbidity, and pH changes immediately and 15, 60, and 120 minutes after mixing. Incompatibility was defined as precipitation, color change, a positive Tyndall test, a change in turbidity of ≥0.5 nephelometric turbidity unit, or a change in pH of ≥1 unit during the 120-minute observation period. RESULTS: Of the 95 i.v. drugs tested, ceftolozane-tazobactam was compatible with 86 drugs in both diluents; notably, it was compatible with metronidazole in both solutions. No substantial pH changes were observed in any tested combination. Ceftolozane-tazobactam was incompatible with albumin, amphotericin B, caspofungin, cyclosporine, nicardipine, and phenytoin sodium due to turbidity changes and with propofol due to formation of an oily layer. CONCLUSION: Ceftolozane-tazobactam 15 mg (10 mg of ceftolozane and 5 mg of tazobactam)/mL was physically compatible with 86 of 95 study drugs tested in both 0.9% sodium chloride injection and 5% dextrose injection during simulated Y-site administration.

Physical compatibility of isavuconazonium sulfate with select i.v. drugs during simulated Y-site administration.

PURPOSE: The physical compatibility of isavuconazonium sulfate with 95 i.v. drugs during simulated Y-site administration was studied. METHODS: Isavuconazonium sulfate for injection and all other drugs were reconstituted according to the manufacturer's recommendation and further diluted with 0.9% sodium chloride injection or 5% dextrose injection to a final concentration (1.5 mg/mL for isavuconazonium sulfate and standard concentrations used clinically for other drugs). A Y site was simulated in glass culture tubes by mixing 5 mL of the tested drug and isavuconazonium sulfate solutions in each diluent. Incompatibility was defined as changes in visual characteristics or increases in turbidity by greater than 0.5 nephelometric turbidity units over the 120-minute experiment. RESULTS: Of the 95 drugs tested, isavuconazonium sulfate was physically compatible with 66 drugs in 0.9% sodium chloride injection and 60 drugs in 5% dextrose injection. Incompatibility was observed with albumin, amphotericin B deoxycholate, amphotericin B lipid complex, amphotericin B liposome, ampicillin-sulbactam, cefazolin, cefepime, ceftaroline fosamil, ceftazidime, ceftriaxone, cefuroxime, colistimethate sodium, cyclosporine, ertapenem, esomeprazole, filgrastim, fosphenytoin, furosemide, heparin, meropenem, methylprednisolone, micafungin, phenytoin, potassium phosphate, propofol, sodium bicarbonate, sodium phosphate, and tedizolid. Azithromycin, bumetanide, penicillin G potassium, and piperacillin-tazobactam were incompatible with isavuconazonium sulfate in 5% dextrose injection only. CONCLUSION: Of the 95 drugs tested, isavuconazonium sulfate 1.5 mg/mL was physically compatible with 66 drugs in 0.9% sodium chloride injection and 60 drugs in 5% dextrose injection. Incompatibility was observed with 18 antimicrobials, including most cephalosporins tested, and 14 other i.v. drugs in at least 1 of the 2 tested diluents.

Complete prevention of blood loss with self-sealing haemostatic needles.

Bleeding is largely unavoidable following syringe needle puncture of biological tissues and, while inconvenient, this typically causes little or no harm in healthy individuals. However, there are certain circumstances where syringe injections can have more significant side effects, such as uncontrolled bleeding in those with haemophilia, coagulopathy, or the transmission of infectious diseases through contaminated blood. Herein, we present a haemostatic hypodermic needle able to prevent bleeding following tissue puncture. The surface of the needle is coated with partially crosslinked catechol-functionalized chitosan that undergoes a solid-to-gel phase transition in situ to seal punctured tissues. Testing the capabilities of these haemostatic needles, we report complete prevention of blood loss following intravenous and intramuscular injections in animal models, and 100% survival in haemophiliac mice following syringe puncture of the jugular vein. Such self-sealing haemostatic needles and adhesive coatings may therefore help to prevent complications associated with bleeding in more clinical settings.

Use of safety-engineered devices by healthcare workers for intravenous and/or phlebotomy procedures in healthcare settings: a systematic review and meta-analysis.

BACKGROUND: The acquisition of needle-stick injuries (NSI) in a healthcare setting poses an occupational hazard of transmitting blood-borne pathogens from patients to healthcare workers (HCWs). The objective of this study was to systematically review the evidence about the efficacy and safety of using safety-engineered intravenous devices and safety-engineered phlebotomy devices by HCWs. METHODS: We included randomized and non-randomized studies comparing safety-engineered devices to conventional/standard devices that lack safety features for delivering intravenous injections and/or for blood-withdrawal procedures (phlebotomy). The outcomes of interest included NSI rates, and blood-borne infections rates among HCWs and patients. We conducted an extensive literature search strategy using the OVID interface in October 2013. We followed the standard methods for study selection and data abstraction. When possible, we conducted meta-analyses using a random-effects model. We used the GRADE methodology to assess the quality of evidence by outcome. RESULTS: We identified twenty-two eligible studies: Twelve assessed safety-engineered devices for intravenous procedures, five for phlebotomy procedures, and five for both. Twenty-one of those studies were observational while one was a randomized trial. All studies assessed the reduction in NSIs among HCWs. For safety-engineered intravenous devices, the pooled relative risk for NSI per HCW was 0.28 [0.13, 0.59] (moderate quality evidence). The pooled relative risk for NSI per device used or procedure performed was 0.34 [0.08,1.49] (low quality evidence). For safety-engineered phlebotomy devices, the pooled relative risk for NSI per HCW was 0.57 [0.38, 0.84] (moderate quality evidence). The pooled relative risk for NSI per device used or procedure performed was 0.53 [0.43,0.65] (moderate quality evidence). We identified no studies assessing the outcome of blood-borne infections among healthcare workers or patients. CONCLUSION: There is moderate-quality evidence that the use of safety-engineered devices in intravenous injections and infusions, and phlebotomy (blood-drawing) procedures reduces NSI rates of HCWs.

Use of intra-osseous access in adults: a systematic review.

BACKGROUND: Indications for intra-osseous (IO) infusion are increasing in adults requiring administration of fluids and medications during initial resuscitation. However, this route is rarely used nowadays due to a lack of knowledge and training. We reviewed the current evidence for its use in adults requiring resuscitative procedures, the contraindications of the technique, and modalities for catheter implementation and skill acquisition. METHODS: A PubMed search for all articles published up to December 2015 was performed by using the terms "Intra-osseous" AND "Adult". Additional articles were included by using the "related citations" feature of PubMed or checking references of selected articles. Editorials, comments and case reports were excluded. Abstracts of all the articles that the search yielded were independently screened for eligibility by two authors and included in the analysis after mutual consensus. In total, 84 full-text articles were reviewed and 49 of these were useful for answering the following question "when, how, and for which population should an IO infusion be used in adults" were selected to prepare independent drafts. Once this step had been completed, all authors met, reviewed the drafts together, resolved disagreements by consensus with all the authors, and decided on the final version. RESULTS: IO infusion should be implemented in all critical situations when peripheral venous access is not easily obtainable. Contraindications are few and complications are uncommon, most of the time bound to prolonged use. The IO infusion allows for blood sampling and administration of virtually all types of fluids and medications including vasopressors, with a bioavailability close to the intravenous route. Unfortunately, IO infusion remains underused in adults even though learning the technique is rapid and easy. CONCLUSIONS: Indications for IO infusion use in adults requiring urgent parenteral access and having difficult intravenous access are increasing. Physicians working in emergency departments or intensive care units should learn the procedures for catheter insertion and maintenance, the contraindications of the technique, and the possibilities this access offers.

Bolus versus continuous infusion of microbubble contrast agent for liver ultrasound by using an automatic power injector in humans: A pilot study.

PURPOSE: To evaluate the feasibility of using continuous infusion, in comparison with bolus injection, of a sulfur hexafluoride-microbubble contrast agent to prolong the duration of hepatic parenchymal enhancement in humans during sonographic examination. METHODS: This pilot study was approved by our institution's ethics committee. Ten patients (5 men and 5 women; mean age ± SD, 65 ± 10 years) each received two injections: a bolus injection (2 ml/s) and then continuous infusion (0.5 ml/min) of the contrast agent by using an automatic injector. Acquired cine clips were transferred to a personal computer, and the video intensity was quantified by dedicated software. RESULTS: From the time of the first microbubble visualization in the scanning plane, maximal enhancement was reached in 6.3 ± 0.94 seconds after bolus injection and in 13.9 ± 1.44 seconds during continuous infusion (p = 0.002, Wilcoxon's test for paired data). Compared with bolus injection, continuous infusion prolonged the duration of contrast enhancement (4.3 minutes ± 42 seconds versus 7.3 minutes ± 40 seconds; p = 0.002), although no statistically significant difference in maximal enhancement was observed (45 ± 18% for bolus injection and 39 ± 6% for continuous infusion; p = 0.62). CONCLUSIONS: Continuous infusion of sulfur hexafluoride-filled microbubbles via an automatic power injector prolongs hepatic contrast enhancement without significantly modifying the maximal enhancement over that at baseline. These data, coming from a pilot study, can be used to design a larger study with adequate statistical power.