A Case Report of Cardiac Arrest After Intravenous Administration of Sulfur Hexafluoride (Lumason®) Ultrasound Enhancing Agent

Ultrasound enhancing agents (UEAs) are medications that enable clear visualization of ultrasound images. While large studies have demonstrated the safety of these agents, case reports of life-threatening reactions temporally associated with their use have been published and reported to the Food and Drug Administration. Current literature describes the most serious adverse reactions due to UEAs to be allergic in nature; however, embolic phenomena may play a role as well. Here, we report a case of unexplained cardiac arrest following the administration of sulfur hexafluoride (Lumason®) in an adult inpatient undergoing echocardiography where resuscitative efforts were ultimately unsuccessful, and review possible mechanisms of cardiac arrest based on prior published literature.

Safety findings after intravenous administration of sulfur hexafluoride microbubbles to 463,434 examinations at 24 centers

OBJECTIVES

We aimed to evaluate the safety of the ultrasound contrast agent sulfur hexafluoride microbubbles in a large group of patients referred for routine contrast-enhanced ultrasound (CEUS).

METHODS

A retrospective assessment was made of all patients that received sulfur hexafluoride microbubbles intravenously for CEUS at 24 centers between January 2006 and April 2019. Patient demographic details, examination type, and the dose of sulfur hexafluoride microbubbles administered were recorded with specific adverse events (AEs) documentation tools at each center. All AEs were recorded as serious or non-serious. Non-serious AEs were classified by intensity as mild, moderate, or severe according to ACR criteria. The frequencies of AEs across patient subgroups were compared using the chi-square test.

RESULTS

A total of 463,434 examinations were evaluated. Overall, 157 AEs (153 [0.033%] non-serious; 4 [0.001%] serious) were reported after sulfur hexafluoride microbubbles administration, giving an AE frequency of 0.034% (157/463,434). Among the non-serious AEs, 66 (0.014%) were mild, 70 (0.015%) moderate, and 17 (0.004%) severe in intensity. The liver was the most common examination site, presenting an AE frequency of 0.026%. The highest AE frequency (0.092%) was for patients undergoing CEUS for vascular disease. There were no significant gender differences in either the total number or the severity of non-serious AEs (chi-square = 2.497, p = 0.287). The onset of AEs occurred within 30 min of sulfur hexafluoride microbubbles administration in 91% of cases.

CONCLUSION

The frequency of AEs to sulfur hexafluoride microbubbles is very low and severe reactions are rare, confirming that sulfur hexafluoride microbubbles are appropriate for routine CEUS applications.

KEY POINT

• The frequency of AEs to sulfur hexafluoride microbubbles is very low and severe reactions are rare.

Safety Analysis of Adverse Events of Ultrasound Contrast Agent Lumason/SonoVue in 49,100 Patients

This study assessed the incidence of mild, moderate and severe adverse events (AEs) and examined their association with age, sex, body region examined, time to event and duration of the AE(s) in a large cohort of patients who underwent contrast-enhanced ultrasound (CEUS) with Lumason/SonoVue. In this retrospective observational study, 49,100 patients who underwent CEUS were analyzed. Forty-three (0.088%) patients experienced AEs, with 23 (0.047%) patients experiencing mild AEs, 13 (0.026%) experiencing moderate AEs and 7 (0.014%) experiencing severe AEs. No fatal event occurred. There was no age- or sex-related difference in the incidence of the AE(s) (p = 0.158 and p = 0.474). Inpatients (0.17%) more often experienced AEs than outpatients (0.06%, p = 0.003). The mean time to event for mild and moderate AEs was 14.50 ± 6.96 and 15.75 ± 10.40 min, respectively, whereas that for severe AEs was 1.89 ± 1.21 min after the injection. The remission time for mild and moderate AEs was approximately 30-40 min, and all patients with severe AEs recovered within 12 h. Twenty-one (48.8%) patients received medical treatment. In summary, Lumason/SonoVue has a good safety profile with a low incidence of AEs, most of which are mild with a short time to event and duration.

Safety and parents´ acceptance of ultrasound contrast agents in children and adolescents - contrast enhanced voiding urosonography and contrast enhanced ultrasound

AIMS

To evaluate the safety of the contrast enhanced voiding urosonography (ceVUS) and contrast enhanced ultrasound (CEUS) in children and adolescence and to receive data about parents' acceptance of intravesical and intravenous application of sulfur hexafluoride.

MATERIAL AND METHODS

In this prospective, single centre study conducted over a 1 year study period, parents of 56 children (f/m=32/24; mean age 3.1 years; range 3 weeks - 15.9 years) with ceVUS and of 30 children (f/m=15/15; mean age 10.5 years; range 2 months - 17.7 years) with CEUS agreed to be included. A standardized telephone survey about the acceptance of the parents during and after the procedure as well as the adverse events (AE) were conducted within three days of the examination.

RESULTS

The parents would agree with the use of both ceVUS and CEUS as a diagnostic tool again in 96% (54/56) or 100% (30/30) of the cases, respectively and 92.9% (52/56) would prefer ceVUS to voiding cystourethrography (VCUG). In addition, 83.3% (25/30) would prefer CEUS to CT and 73.3% (22/30) would prefer CEUS to MRI. AE were reported in 3.6% after ceVUS (2/56; skin rash, mild fever) and in 3.3% after CEUS (1/30; vomiting). AE were subacute and self‑limited.

CONCLUSIONS

The vast majority of parents prefer ceVUS and CEUS to VCUG, CT or MRI because of the safety profile of the contrast agent and diagnostic accuracy.

Type III Kounis syndrome after administration of an echocardiography contrast agent

A dobutamine stress echocardiogram was performed in a 72-year-old woman to assess an intermediate lesion in the left anterior descending artery. After administration of the echocardiography contrast agent, she presented with an anaphylactic reaction and in that context a subacute thrombosis of a drug-eluting stent implanted 15 days before. This is a case of the so-called type III Kounis syndrome.

The role of multiparametric ultrasound in the diagnosis of paediatric scrotal pathology

Multiparametric ultrasound (MPUS), combining conventional techniques (greyscale and colour Doppler ultrasound), ultrasound strain elastography, and contrast-enhanced ultrasound (CEUS), has been successfully used in the assessment of adult scrotal pathology. Contrast-enhanced ultrasound can confidently establish testicular tissue vascularity even in the small-volume paediatric testis. Elastography provides further assessment of tissue stiffness, potentially adding useful diagnostic information. In children, ultrasonography is particularly advantageous, being safe, radiation-free and negating the need for sedation or general anaesthesia during the imaging evaluation. In this review article, we aim to familiarise readers with the MPUS scanning protocol used for paediatric scrotal examination and provide an overview of scrotal MPUS features, with particular focus to clinical indications where MPUS may be advantageous over conventional ultrasonography.

Adverse reactions after the use of SonoVue contrast agent: Characteristics and nursing care experience

The aim of this study was to analyze the clinical manifestations of adverse reactions after the use of SonoVue contrast agent from a large retrospective database, and to evaluate the nursing care strategies and the efficacy of standardized procedure for adverse reactions of SonoVue (SPARS).From January 1, 2012 to December 30, 2018, 34,478 cases of contrast-enhanced ultrasonography were performed in our center. The clinical manifestations of adverse reactions after the use of SonoVue contrast agent were identified and analyzed. The nursing care strategies were evaluated and the outcomes of patients with moderate and severe adverse reactions before and after the application of SPARS were compared.Of the 34,478 cases, 40 cases (0.12%) of adverse reactions after the use of SonoVue were identified. Adverse reactions included anaphylatic shock, skin allergies, nausea or vomiting, dizziness or headache, numbness, chest distress, back pain, and local reactions of the injection site. Most of the adverse reactions were mild and self-limited. Only 3 cases of anaphylatic shock and 2 cases of severe rash underwent further treatments. The 3 patients who were managed by SPARS recovered quicker and spent less comparing with the other 2 patients who were not.SonoVue was a safe contrast agent, with few and mostly mild adverse reactions. SPARS may be an efficient way in tackling moderate to severe adverse reactions, although of which the incidence was rare.

Safety of Sulfur Hexafluoride Microbubbles in Sonography of Abdominal and Superficial Organs: Retrospective Analysis of 30,222 Cases

OBJECTIVES

The purpose of this study was to investigate the safety of the sulfur hexafluoride microbubble contrast agent SonoVue (Bracco SpA, Milan, Italy) and to implement precautions with the intent of further improving the safety of this contrast agent.

METHODS

A total of 30,222 patients undergoing contrast-enhanced sonography of abdominal and superficial organs in our hospital from January 2005 to December 2014 were retrospectively investigated. SonoVue was used as the ultrasound contrast agent. The symptoms and treatments of adverse reactions occurring during the contrast-enhanced sonographic examinations were reviewed and analyzed.

RESULTS

No patient died as a result of any adverse reaction. Six patients (0.020%) had adverse reactions of varying degrees, including 2 patients (0.007%) who had signs of early anaphylactic shock (chest tightness, palpitations, sweating, and rapid and weak pulse, followed by cyanosis, a disappearing pulse, and a drop in blood pressure) that improved after active rescue. The remaining 4 patients developed the following: redness and a rash on the arm above the injection site, nasal bleeding and nausea, nausea and vomiting, and back pain with numbness of the lips and limbs. Symptoms in these 4 patients self-resolved after a period of rest.

CONCLUSIONS

Contrast-enhanced sonography with sulfur hexafluoride microbubbles had good clinical safety, but rare adverse reactions were observed. A comprehensive emergency plan and rescue measures for adverse reactions should be prepared and made available to minimize the occurrence of negative clinical outcomes.

Safety of intravenous application of second-generation ultrasound contrast agent in children: prospective analysis

The goal of the work described here was to assess the safety profile of intravenous second-generation ultrasound contrast agents (UCAs) containing sulfur hexafluoride in pediatric contrast-enhanced ultrasound. Between 2010 and 2013, a total of 167 examinations were performed in 137 children referred by the Oncology Department. Approval by an Independent Ethical Review Board on Scientific Research for the intravenous use of an UCA containing sulfur hexafluoride in children with oncologic diseases was obtained. Consent for UCA administration was acquired from the parents or legal guardians. Severe anaphylactic reaction was observed in 0.6% (n = 1). No other adverse events during or after intravenous administration of contrast were observed in the examined group (no changes in heart rate and rhythm, blood pressure, oxygen saturation or respiratory rate). There were no reports of subjective flushing, nausea, transient headaches or altered taste. Although second-generation ultrasound contrast agents are considered potentially safe, all investigators should be prepared for the development of adverse reactions and have provisions in place for all pediatric intravenous contrast-enhanced ultrasound examinations. More multicenter studies are essential to determination of an accurate UCA safety profile.

Contrast-enhanced ultrasound for evaluation of high-intensity focused ultrasound treatment of benign uterine diseases: retrospective analysis of contrast safety

As a noninvasive treatment technique, ultrasound-guided high-intensity focused ultrasound (HIFU) has been considered as a routine treatment for uterine fibroids and adenomyosis in China. Contrast-enhanced ultrasound (CEUS) has been proposed as another option to assess the treatment efficacy during HIFU treatment. The aim of this investigation is to evaluate the adverse effects of HIFU ablation for benign uterine diseases in a group of patients studied with ultrasound contrast agent (UCA), in comparison with a group of patients not exposed to UCA. From November 2010 to December 2013, 2604 patients with benign uterine diseases were treated with HIFU. Among them, 1300 patients were exposed to an UCA, whereas 1304 patients were not.During HIFU procedure, the incidences of leg pain, sacral/buttock pain, groin pain, treatment area pain, and the discomfort "hot" sensation on skin were higher in the patients who were exposed to SonoVue (Bracco, Milan, Italy) than those who were not (20.5% vs 11.7%, 52.5% vs 42.3%, 6.5% vs 4.5%, 68.9% vs 55.4%, and 48.1% vs 42.9%, respectively). Among the postoperative adverse effects, the incidence of lower abdominal pain was significantly higher in patients who were exposed to an UCA than those who were not (51.2% vs 39.9%, P < 0.05). Two patients who were exposed to an UCA had acute renal function failure.In conclusion, UCA may increase the incidences of some common HIFU-related adverse effects during HIFU treatment for benign uterine diseases, but most of which were acceptable and self-limited. After HIFU treatment, renal function should be monitored in patients with a history of hypertension or taking nonsteroidal anti-inflammatory drugs.

Efficacy and safety of recombinant tissue plasminogen activator and gas versus bevacizumab and gas for subretinal haemorrhage

PURPOSE

To report the 12 months efficacy of initial intravitreal bevacizumab or intravitreal recombinant tissue plasminogen activator (rtPA) combined with expansile gas in patients with subretinal haemorrhage caused by neovascular age-related macular degeneration (AMD).

METHODS

Forty-five eyes of 45 patients with subretinal haemorrhage (1-5 disc diameters) involving the fovea secondary to neovascular AMD were evaluated retrospectively consecutively. Thirty-two eyes underwent treatment with rtPA (50 μg/0.05 ml) combined with intravitreal sulphur hexafluoride (SF6). The other 13 eyes were treated with bevacizumab (1.25 mg/0.05 ml) and SF6. Thereafter, all patients received Vascular Endothelial Growth Factor (anti-VEGF) treatment according to modified PrONTO criteria. Main outcome was change of best-corrected visual acuity (VA) at 12 months as determined by Early Treatment Diabetic Retinopathy (ETDRS).

RESULTS

There was more improvement in patients initially treated with rtPA and gas (14 letters; bevacizumab and gas eight letters) and not suffering from adverse events. The incidence of vitreous haemorrhages was significantly higher in the rtPA group (nine of 32 versus one of 13, p < 0.01). In both groups, an average of 3.5 anti-VEGF injections were performed per patient during 12 months (no difference between both groups).

CONCLUSION

Both initial treatment regimen lead to improved functional results after 1 year. However, patients, not suffering from adverse events, who underwent initial treatment with rtPA and gas showed better results. To maintain VA, controlling neovascular AMD by anti-VEGF treatment regime after initial treatment with rtPA+gas is important for all cases.

Automated three-dimensional coded contrast imaging hysterosalpingo-contrast sonography: feasibility in office tubal patency testing

OBJECTIVE

To evaluate the feasibility of transvaginal hysterosalpingo-contrast sonography (HyCoSy) with new automated three-dimensional coded contrast imaging (3D-CCI) software in the evaluation of tubal patency and visualization of tubal course.

METHODS

Patients undergoing HyCoSy with automated 3D-CCI software were evaluated prospectively. First, to evaluate the feasibility of 3D visualization of tubal course, we performed consecutive volume acquisitions while injecting SonoVue contrast agent. We then performed conventional two-dimensional (2D) real-time HyCoSy to confirm tubal patency status by detection of saline and air bubbles moving through the Fallopian tubes and around the ovaries. We also evaluated visualization with CCI of the contrast agent around the ovaries, side effects and pain during and after the procedure, by visual analog scale (VAS) (ranging from 0 to 10, with 0 corresponding to no pain and 10 corresponding to maximum pain).

RESULTS

A total of 126 patients (252 tubes) underwent 3D-CCI HyCoSy followed by 2D real-time HyCoSy. According to the final 2D real-time evaluation, bilateral tubal patency was observed in 111 patients, bilateral tubal occlusion in four patients and unilateral tubal patency in 11 patients. The concordance rate for tubal patency status between the first 3D volume acquisition and the final 2D real-time evaluation was 84% and that between the second 3D volume acquisition and the final 2D real-time evaluation was 97%. A pain score >5 on VAS was recorded in 58% of patients during the procedure, but a pain score ≤ 5 was recorded in 85.7% of patients immediately after the procedure.

CONCLUSIONS

HyCoSy with automated 3D-CCI technology retains the advantages of conventional 2D HyCoSy while overcoming the disadvantages. 2D HyCoSy is highly observer-dependent and is only accurate in the hands of experienced investigators; by obtaining a volume of the uterus and tubes, automated 3D volume acquisition permits visualization of the tubes in the coronal view and of the tubal course in 3D space, and should allow less experienced operators to evaluate tubal patency status relatively easily.

Guidelines and good clinical practice recommendations for contrast enhanced ultrasound (CEUS) in the liver--update 2012: a WFUMB-EFSUMB initiative in cooperation with representatives of AFSUMB, AIUM, ASUM, FLAUS and ICUS

Initially, a set of guidelines for the use of ultrasound contrast agents was published in 2004 dealing only with liver applications. A second edition of the guidelines in 2008 reflected changes in the available contrast agents and updated the guidelines for the liver, as well as implementing some non-liver applications. Time has moved on, and the need for international guidelines on the use of CEUS in the liver has become apparent. The present document describes the third iteration of recommendations for the hepatic use of contrast enhanced ultrasound (CEUS) using contrast specific imaging techniques. This joint WFUMB-EFSUMB initiative has implicated experts from major leading ultrasound societies worldwide. These liver CEUS guidelines are simultaneously published in the official journals of both organizing federations (i.e., Ultrasound in Medicine and Biology for WFUMB and Ultraschall in der Medizin/European Journal of Ultrasound for EFSUMB). These guidelines and recommendations provide general advice on the use of all currently clinically available ultrasound contrast agents (UCA). They are intended to create standard protocols for the use and administration of UCA in liver applications on an international basis and improve the management of patients worldwide.

[New aspects in sonography of the liver]

Ultrasound-based technologies are competing more and more success-fully against computerized tomography and magnetic resonance based imaging procedures. This thanks to technological improvements as well as accumulating evidence, stemming from properly conducted controlled clinical studies. The reduced cost and radiation safety issues are additional arguments in its favor. This article reviews new developments in ultrasound medicine as applied to the liver. Emphasis lies on new data related to contrast-ultrasound (Sulphur Hexafluoride SonoVue®) which allows a dynamic analysis of liver perfusion and hence improved characterization of focal liver lesions, such as metastases of extrahepatic tumors, regenerative nodules in patients with liver cirrhosis, focal nodular hyperplasia, hepatocellular carcinoma, liver hemangioma, liver adenoma and or focal hypo-respectively hypersteatosis. This article also deals with important new techniques, which allow assessment of liver stiffness such as transient elastography (Fibroscan), ARFI (Acoustic Radiation Force Impulse) or real-time-tissue elastography. These new techniques will help us to assess and quantify the levels of liver steatosis with more precision and permit accurate follow-up measurements.

Intravenous application of second-generation ultrasound contrast agents in children: a review of the literature

CEUS examinations using second-generation ultrasound contrast agents (UCA) are conducted in children, despite not being registered for individuals less than 18 years of age. We searched the Medline® database through Pubmed® and Scopus database, in order to find articles in which UCA were administered intravenously in patients under the age of 18. We analyzed in detail 9 papers (7 case reports, 2 original research studies), describing the examinations with intravenous administration of the UCA in children, and 23 original papers, in which the study group included at least one individual under the age of 18. Neither of the analyzed studies included any reports of adverse effects after UCA administration.

Echocardiography: fatal reactions to contrast agents

Before performing an investigative procedure, it is important to first determine whether the results will influence therapeutic management of the patient concerned.

In situ kidney insonation with microbubble contrast agents does not cause renal tissue damage in a porcine model

OBJECTIVE

Knowledge and quantification of the microcirculation are very important for estimating the status of an organ. Real-time contrast-enhanced sonography assesses microvascular tissue perfusion. This technique has been proposed as innocuous; however, data from experimental animals (rats) have shown renal interstitial microhemorrhage after the procedure. Therefore, we developed a porcine model to explore potential renal damage that in situ exposure might cause.

METHODS

Kidneys from 8 anesthetized pigs were surgically exposed. An ultrasound contrast agent (sulfur hexafluoride) was infused through the femoral vein in a continuous perfusion. Destructive ultrasonic flashes were applied with a high mechanical index over only 1 kidney (the contralateral kidney was used as a control). Blinded histologic and laboratory analyses were performed to reveal any lesions.

RESULTS

Histologic analysis of the kidney samples showed no evidence of renal damage. Biochemical parameters that could represent renal tissue damage and hemoglobin levels did not change after the microbubble-ultrasound interaction.

CONCLUSIONS

The ultrasound contrast agent-ultrasound interaction in anesthetized pig kidneys under the output level for the imaging visualization and microbubble destruction used did not cause tissue damage. Our results suggest that this procedure could be used in humans for regular analysis of the kidney microcirculation with minimal risk of tissue damage.

[Survey of the use of long-lasting expanding gases in ophthalmology in Japan]

PURPOSE

To survey the use of long-lasting expanding gases in ophthalmology in Japan.

SUBJECTS AND METHODS

A questionnaire was sent to 1,236 teaching hospitals approved by the Japanese Ophthalmological Society requesting information regarding indications, methods, efficacy and complications related to the use of long-lasting expanding gases administered from January through December 2005.

RESULTS

Four-hundred and fifty-nine hospitals responded to the survey (response rate 37.1%). A total of 174,221 ophthalmic surgeries were performed during the survey period, with long-lasting expanding gases used in 19,816 of cases (11.4%). The surgical procedure was vitrectomy in 89.6% of cases in which gas was administered. The most frequent indication for gas use was rhegmatogenous retinal detachment, for which SF6 was the preferred gas. Industrial use gas was utilized in 76.1% of cases, while 22.4% of cases received medical use gas. Increase in intraocular pressure was the most common complication of intraocular gas tamponade (3121 cases, 15.7%), followed by cataract formation. Ninety-eight percent of ophthalmologists responding supported the use of long-lasting expanding gases with vitrectomy, 85% with scleral buckling procedures, and 84% with surgery to remove subretinal hemorrhage. The consensus was that substantial deterioration of surgical results would occur if long-lasting expanding gases could not be used.

CONCLUSIONS

Long-lasting expanding gases are being widely administered in ophthalmology in Japan, and appear to have good efficacy for a variety of indications. Several complications related to the use of these gases were reported, however the rates of complications were low.

Voiding urosonography with ultrasound contrast agents for the diagnosis of vesicoureteric reflux in children. I. Procedure

Voiding urosonography (VUS) encompasses examination of the urinary tract with intravesical administration of US contrast agent (UCA) for diagnosis of vesicoureteric reflux (VUR). The real breakthrough for US examination of VUR came with the availability of stabilized UCAs in the mid-1990s. This article presents a comprehensive review of various procedural aspects of VUS. Different US modalities are available for detecting the echogenic microbubbles: fundamental mode, colour Doppler US, harmonic imaging and dedicated contrast imaging with multiple display options. The reflux is graded (1 to 5) in a similar manner to the system used in voiding cystourethrography (VCUG). The most commonly used UCA for VUS, Levovist, is galactose-based and contains air-filled microbubbles. The recommended concentration is 300 mg/ml at a dose of 5-10%, or less than 5%, of the bladder filling volume when using fundamental or harmonic imaging modes, respectively. There are preliminary reports of VUS using a second-generation UCA, SonoVue. Here the UCA volume is less than 1% of the bladder filling volume. There is no specific contraindication to intravesical administration of UCA. The safety profile of intravesical Levovist is very high with no reports of side effects over a decade of use in VUS.

Characterization and detection of hepatocellular carcinoma (HCC): comparison of the ultrasound contrast agents SonoVue (BR 1) and Levovist (SH U 508A)--comparison of SonoVue and Levovist in HCC

PURPOSE

SonoVue and Levovist (SH U 508A) are both ultrasound contrast agents, which are helpful in characterization and detection of malignant liver lesions. This study was performed to compare both contrast agents according to the capability to diagnose hepatocellular carcinoma (HCC).

MATERIALS AND METHODS

In a prospective study, 65 patients with histologically proven hepatocellular carcinoma (HCC) were examined with both, Levovist and SonoVue. In all patients HCC lesions had been detected by B-mode sonography before the study start. After injection of 2.4 ml SonoVue i. v., the liver was examined continuously for up to three minutes using "low MI"-pulse inversion sonography. For the Levovist-examinations 2.5 g Levovist were injected i. v. After a delay of at least 2.5 minutes without scanning, the liver was examined with three different scans using "high-MI"-pulse-inversion sonography.

RESULTS

The examination was technically sufficient in 98% after SonoVue-injection and in 92% after Levovist-injection (n. s.). Comparison of the results was performed for the 60/65 patients (61 lesions), in which both methods were technically sufficient. After SonoVue-injection contrast-enhancement in the arterial phase was found in 79% (48/61) of the lesions. Demarcation of the HCC-lesion in the late phase was found in 89% of the SonoVue-examinations and in 98% of the Levovist-examinations (p < 0.05). Early SonoVue-enhancement and/or demarcation in SonoVue late-phase was found in 93% of the HCC-lesions (n. s. compared to Levovist-late phase).

CONCLUSION

Levovist-late phase has a higher sensitivity in predicting lesion dignity of HCC-lesions compared to SonoVue-late phase, but not compared to combination of SonoVue-early phase and late phase.

[Complications of internal tamponade with gas or silicone]

This article presents the vitreous substitutes used in vitreoretinal surgery, emphasizing the complications of intraocular tamponade: refractive considerations, common toxicity of gases and silicone oil, specific toxicity of silicone oil, intraocular pressure abnormalities and lenticular complications.

Effects of simultaneous application of ultrasound and microbubbles on intracerebral hemorrhage in an animal model

Microbubble-enhanced sonothrombolysis (MEST) may be an alternative therapeutic option in ischemic stroke. Clinical study of the efficacy of MEST as an adjunct stroke therapy, before imaging with CT or MRI, requires experimental data on the safety of this approach in the presence of hemorrhagic stroke. We, therefore, investigated the effect of diagnostic transcranial ultrasound combined with microbubbles (US + MB) in an experimental animal model of intracerebral hemorrhage (ICH). ICH was induced in anesthetized rats by intracerebral collagenase injection. Transcranial ultrasound (2 MHz, mechanical index 1.3, 1051 kPa) was applied 3 h after ICH induction to rat brains for 30 min during a continuous IV infusion of sulfur hexafluoride microbubbles (SonoVue). The size of cerebral hemorrhage, the extent of brain edema, and the amount of apoptosis were compared with those from control rats with ICH but without US + MB. Results showed no significant effect of US + MB on hemorrhage size (control 23.3 +/- 10.7 mm(3), US + MB 20.3 +/- 5.8 mm(3)), on the extent of brain edema (control 3.3 +/- 2.0%, US +MB 3.5 +/- 1.9%), or on the rate of apoptosis (control 5.2 +/- 1.5%, US + MB 5.2 +/- 1.0%). We conclude that diagnostic ultrasound in combination with microbubbles does not cause additional damage to the rat brain during ICH in our experimental set-up. This finding provides support for the use of MEST as an early stroke therapy.

Sequential Descemet's membrane detachments and intraocular lens haze secondary to SF6 or C3F8

PURPOSE

To report an unusual complication of treatment in the case of a Descemet's membrane detachment.

METHODS

Observational case report.

RESULTS

A 79-year-old woman presented for elective cataract surgery. Ocular risk factors identified preoperatively included moderately shallow anterior chambers bilaterally, previously treated with bilateral YAG peripheral iridotomies. After a clear corneal section during phacoemulsification, large Descemet's tears on introducing the micro finger and phaco probe were noticed. Conversion to an extracapsular technique was necessary because of poor view. Similar peroperative Descemet's detachments were noticed in the contralateral eye during phacoemulsification by a senior surgeon a year later. Postoperatively, the Descemet's detachments were managed by intracameral SF6 and later C3F8 gas. A few weeks later, a fine haze was noticed under the anterior surface of the intraocular lens (IOL). Corneal edema persisted and corneal decompensation ensued. Both eyes needed penetrating keratoplasties. The right eye needed an IOL exchange due to IOL haze.

CONCLUSIONS

In this case the SF6 or C3F8 gas may have produced the unexpected effect of an anterior IOL haze. The mechanism of this phenomenon is unknown. To the knowledge of the authors, this effect has not been observed previously with SF6 or C3F8 gas. This haze was visually significant and required an IOL exchange. To the knowledge of the authors this is the first report of this nature. The authors advise caution when using intracameral SF6 or C3F8 gas for repair of Descemet's membrane detachment with this type of IOL.

The safety of Sonovue in abdominal applications: retrospective analysis of 23188 investigations

The aim of the present retrospective study was to assess the incidence of adverse events (AE) of a second-generation ultrasound contrast agent in real clinical practice. A total of 28 Italian Centres provided data on the postmarketing use of SonoVue (Bracco Spa, Milan, Italy) in abdominal examination performed between December 2001 and December 2004. A total of 23 188 investigations were reported. No fatal event occurred. AEs were reported in 29 cases, of which only two were graded as serious; the rest, 27, were nonserious (23 mild, three moderate and one severe). The overall reporting rate of serious AE was 0.0086%. Overall, only four AEs required treatment (two serious, two nonserious including one moderate and one severe AEs). In conclusion, the present large-scale retrospective analysis showed that SonoVue has a good safety profile in abdominal applications, with an AE reporting rate lower than or similar to that reported for radiologic and magnetic resonance contrast agents.

Adverse effects associated with SonoVue®use

Conventional ultrasonography (US) has limited accuracy in the detection and characterisation of solid focal liver lesions (FLL). Contrast-enhanced ultrasound (CEUS) significantly improves the diagnostic performance of US in the assessment of FLL. Rare reports of serious adverse events have been reported with CEUS. The rates of adverse reactions reported from the use of ultrasound contrast agents seem comparable to, or lower than, those observed for other imaging modalities that use contrast agents such as computed tomography and magnetic resonance imaging. Improved diagnostic results and diagnostic confidence achieved in conventional CEUS studies of the liver and during the investigational use in the intraoperative CEUS exploration appear to justify the use of this promising modality.

Safety of contrast dobutamine stress echocardiography: A single center experience

BACKGROUND

Contrast is increasingly being used during dobutamine stress echocardiography. However, there are few data regarding the safety of this combination.

METHODS

We retrospectively analyzed 751 consecutive stress echocardiograms, 332 without contrast and 419 with contrast (299 with Sonouve, 120 with Optison). Reported side effects and physiologic data were then compared.

RESULTS

There were no fatalities. The incidence of side effects was similar in the 3 groups. The Optison group had a lower diastolic blood pressure compared with the noncontrast group ( P < .05) at rest, and the Sonovue group had a higher peak heart rate compared with the noncontrast group ( P < .001). Patients receiving Optison had more premature atrial contractions ( P < .05) but there was no difference in the incidence of ventricular tachycardia, supraventricular tachycardia, or vagally mediated episodes.

CONCLUSION

The use of contrast during dobutamine stress echocardiography was not associated with an increased risk of side effects.

[The effect of SonoVue in endocardial border delineation and myocardial perfusion]

OBJECTIVE

To evaluate the enhancement of endocardial border delineation and displaying of myocardial perfusion by the contrast agent SonoVue intravenously.

METHODS

Under mode of fundamental imaging and nonlinear imaging respectively, 90 patients were injected with SonoVue and observed for improvement of endocardial border delineation by two dimension echo. In the meantime, displaying of myocardial perfusion by SonoVue was also investigated under mode of nonlinear imaging. Adverse events were monitored.

RESULTS

(1) SonoVue stained the left heart chambers of the patients right away after the right heart chambers had been stained. Endocardial border delineation of the left heart in 90 patients were all improved by SonoVue. (2) SonoVue can well display myocardial opacification (3) No serious adverse events occurred throughout the study. All nonserious adverse events were minor, mild, and rapidly self-resolving. Total incidence of adverse events was 6.8% and the incidence of adverse events possibly related to SonoVue was 1.1%.

CONCLUSION

SonoVue is a safe transpulmonary agent and can satisfactorily improve the endocardial border delineation and show myocardial perfusion.

[Severe adverse reactions after the use of sulphur hexafluoride (SonoVue) as an ultrasonographic contrast agent]

European Medicines Agency (EMEA) recently took precautionary measures to limit the use of the ultrasonographic contrast agent sulphur hexafluoride (SonoVue) in patients with cardiac disease. Throughout Europe a number of serious allergic reactions with probable secondary cardiovascular problems have been reported. In addition to this, there have been 3 reports of a fatal outcome soon after the administration of SonoVue. For all of these patients there was a risk of serious cardiac complications as a consequence of underlying cardiac problems. In The Netherlands 3 anaphylactic reactions have been reported, two in women aged 59 and 70 years respectively, and one in a man aged 80 years.

[Heterochromia of the Iris after t-PA and Gas Injection of Sulfur Fluoride]

BACKGROUND

Are changes in iris colour and retinal pigment epithelium after t-PA and gas injection and subsequent vitreous haemorrhage caused by blood cells, or is this a toxic effect?

CASE

A 81-year old female presented for vitrectomy with a persistent vitreous haemorrhage two months after t-PA and gas injection because of subretinal macular haemorrhage. Sonographic control revealed attached retina. The examination disclosed a new heterochromia of the iris with a change from blue to green-brown. A discrete anterior chamber flare and blood cells were found. Subsequent vitrectomy revealed a thick, rubber-like haemorrhage in the vitreous with suspect pigmentation. A change in retinal pigmentation was also evident.

CONCLUSION

The cause for the heterochromia and the change in pigmentation of the retinal pigment epithelium remained unclear. It may have been a consequence of the persistent bleeding with iron apposition on the iris. A toxic effect of t-PA has to be discussed which led to the alteration in pigmentation.

Management of glaucoma after retinal detachment surgery

Secondary glaucoma may complicate retinal detachment surgery. Intraocular pressure (IOP) elevation has been described after scleral buckling procedures and vitrectomy with intravitreal injection of gas or silicone oil. Angle-closure glaucoma after scleral buckling develops because of congestion and anterior rotation of the ciliary body. Medical therapy and laser iridoplasty are usually successful in controlling IOP, but the presence of conjunctival scarring and recession and retinal hardware after scleral buckling procedures can make surgical management challenging. Intravitreal injection of expansile gases like sulfur hexafluoride (SF6) and perfluoropropene (C3F8) may produce secondary angle-closure glaucoma with or without pupillary block. Aspiration of a portion of the intraocular gas may be needed, especially if IOP is elevated to a level that may compromise ocular perfusion. Glaucoma also can develop after intravitreal injection of silicone oil secondary to pupillary block, inflammation, synechial angle closure, rubeosis iridis, or migration of emulsified or nonemulsified silicone oil into the anterior chamber. A prophylactic inferior iridectomy at the time of surgery serves to prevent pupillary block. Patients with medically uncontrolled glaucoma after silicone oil injection may require oil removal with or without concurrent glaucoma surgery.

Fixed dilated pupil (Urrets-Zavalia syndrome) after air/gas injection after deep lamellar keratoplasty for keratoconus

PURPOSE

To describe three cases of fixed dilated pupil and presumed iris ischemia (Urrets-Zavalia syndrome) after anterior chamber air/gas injection after deep lamellar keratoplasty for keratoconus.

METHODS

Interventional case series. Three eyes of three patients with keratoconus underwent deep lamellar keratoplasty and intraoperative or postoperative injection of air/gas in the anterior chamber to appose the host-donor lamellar graft interface.

RESULTS

Urrets-Zavalia syndrome was diagnosed on clinical grounds in three cases and was associated with the Descemet membrane microperforation intraoperatively and introduction of air/gas into the anterior chamber intraoperatively or postoperatively.

CONCLUSION

A fixed dilated pupil is an uncommon complication of penetrating keratoplasty for keratoconus that can also develop after deep lamellar keratoplasty. Leaving an air or gas bubble in the anterior chamber of a phakic eye after deep lamellar keratoplasty is a risk factor and should therefore be avoided.

Halogenated compounds and climate change: future emission levels and reduction costs

OBJECTIVES

This work assesses the contribution to climate change resulting from emissions of the group of halogenated greenhouse gases.

METHODS

A bottom-up emission model covering 22 technological sectors in four major regions is described. Emission estimates for 1996 and projection for 2010 and 2020 are presented. The costs for deep cuts into projected emission levels are calculated.

RESULTS

The substances covered by this study have contributed emissions of 1100 +/- 800 MT CO2 equivalents per year in 1996. In terms of their relative contribution to emissions of CO2 equivalents, this corresponds to 3 +/- 2% of global emissions of all anthropogenic greenhouse gases. The wide range of uncertainty is due to the poorly quantified net global warming potential of the ozone depleting substances, which have an indirect cooling effect on climate through the destruction of stratospheric ozone. For annual emissions of HFCs, PFCs and SF6 (which are regulated under the Kyoto Protocol and for which global warming potentials are well defined), the relative contribution is projected to increase to 2% (600 MT CO2 eq.) of global greenhouse gas emissions by 2010. This trend is expected to continue, emissions are projected to grow to a contribution of roughly 3% (870 MT CO2 eq.) in 2020 compared to 0.9% (300 MT CO2 eq.) in 1996. For HFCs, PFCs and SF6, this study identifies global emission reduction potentials of 260 MT CO2 eq. per year in 2010 and 640 MT CO2 eq. per year in 2020 at below US$ 50 per ton. These values correspond to roughly 40% and 75% of projected emissions in 2010 and 2020, respectively.

Clinical safety of SonoVue, a new contrast agent for ultrasound imaging, in healthy volunteers and in patients with chronic obstructive pulmonary disease

RATIONALE AND OBJECTIVES

To evaluate the safety profile of SonoVue, a new echo-contrast agent based on stabilized sulfur hexafluoride (SF6) microbubbles, in healthy volunteers and in patients with chronic obstructive pulmonary disease (COPD).

METHODS

Safety and tolerability of SonoVue were evaluated in 66 healthy volunteers during two placebo-controlled phase I studies (a single intravenous ascending-dose study in 36 volunteers given SonoVue doses of 0.003 to 0.12 mL/kg and a multiple-dose study in 30 subjects given cumulative doses of 0.15 to 0.6 mL/kg) and in 12 patients with COPD of various degrees of clinical severity, who were given SonoVue at a dosage of 4 mL (corresponding to 0.057 mL/kg in a 70-kg patient). Adverse events were monitored up to 48 to 72 hours after administration. All volunteers underwent extensive safety assessments (monitoring of vital signs, electrocardiogram, blood oxygen saturation, laboratory assessments, and Mini-Mental test) up to 24 to 72 hours after administration. In addition, patients with COPD underwent specific lung function tests, such as forced expiratory volume, forced vital capacity, and forced midexpiratory flow.

RESULTS

No serious adverse events occurred throughout the study. All nonserious adverse events were minor, mild, and rapidly self-resolving. No difference in the incidence of adverse events was observed among the various dosages of SonoVue and between SonoVue and placebo. There were no clinically significant changes in any of the safety assessments. No statistically significant differences between SonoVue and placebo were observed in mean forced expiratory volume, forced vital capacity, or forced midexpiratory flow levels. No substantial changes from baseline in blood oxygen saturation were observed for either study agent at any postinjection time point.

CONCLUSIONS

SonoVue showed a good safety profile both in healthy subjects and in patients with COPD.

Hemostatic effects of SF6 after diabetic vitrectomy for vitreous hemorrhage

PURPOSE

To investigate the hemostatic effects of SF6 gas in preventing postoperative vitreous hemorrhage in diabetic vitrectomy.

METHODS

A prospective, randomized study of 33 diabetic eyes with vitreous hemorrhage, treated by vitrectomy. In 17 of our cases SF6 20% was injected into the eye at the end of the operation, while in 16 cases BSS remained in the vitreous cavity.

RESULTS

The incidence of vitreous hemorrhage recurrence was 17.6% for the SF6 group and 12.5% for the BSS group (statistically not significant). Progression of lens opacities was observed in 23.5% of the SF6 group, and in 18.8% of the BSS group (statistically not significant, with a higher incidence in the SF6 group).

CONCLUSIONS

SF6 gas did not show hemostatic effects in the cases studied. Furthermore, it may have contributed to cataract progression. Therefore we suggest that the use of SF6 is not recommended as a treatment modality in preventing new vitreous hemorrhage after diabetic vitrectomy.

Vitreous hemorrhage after intravitreal tissue plasminogen activator (t-PA) and pneumatic displacement of submacular hemorrhage

PURPOSE

To report the immediate complication of dense vitreous hemorrhage after intravitreal injection of tissue plasminogen activator and gas for treatment of two cases of sudden submacular hemorrhage associated with retinal arterial macroaneurysm.

METHODS

Case reports.

RESULTS

Two patients, a 67-year-old woman and a 92-year-old man, presented with sudden vision loss related to submacular hemorrhage from a retinal macroaneurysm. Tissue plasminogen activator at a dose of 50 microg to 75 microg and a sulfur hexafluoride (SF(6)) gas bubble were injected intravitreally under local anesthesia. Dense vitreous hemorrhage was noted on the first postoperative day in both cases, which subsequently required pars plana vitrectomy removal.

CONCLUSION

Sudden severe vitreous hemorrhage may be an immediate complication after intravitreal injection of tissue plasminogen activator and gas for treatment of submacular hemorrhage associated with retinal arterial macroaneurysm.

Intraocular gas tamponades

Intraocular gas tamponades are an important part of vitreoretinal surgery and have become a standard of care. The use of intraocular gas began in 1911. Modem use of intraocular gases as a surgical adjunct is continuously broadening. Today, sulfur hexafluoride and perfluoropropane are increasingly being used as intraocular gas tamponades for a wide range of complicated vitreoretinal diseases. This article reviews the types and function of commonly used gases, their indications and efficacy in certain types of vitreoretinal diseases, and their complications.

Sulfur hexafluoride (SF6): global environmental effects and toxic byproduct formation

This work provides information concerning possible global environmental implications and personnel safety aspects that should be considered during the commercial uses of sulfur hexafluoride (SF6). SF6 is an anthropogenically produced compound, mainly used as a gaseous dielectric in gas insulated switchgear power installations. It is a potent greenhouse gas with a high global warming potential, and its concentration in the earth atmosphere is rapidly increasing. During its working cycle, SF6 decomposes under electrical stress, forming toxic byproducts that are a health threat for working personnel in the event of exposure. Several precautions are recommended to avoid personnel exposure to toxic byproducts: oxyfluoride levels or other byproduct concentrations in the operating gas matrix should be traced to predetermine the overall gas toxicity; contaminants should be systematically considered during maintenance, chamber evacuation and system opening process; small SF6 quantities leaking into air or stagnated pollutant concentrations in the operating field should be analyzed and compared to the threshold limit values and permissible exposure levels. New system design rules (i.e., hermetically sealed gas compartments, gas recycling or disposal in the field area) and different handling policies--both during maintenance and final disposal--now should be considered globally to provide for environmental and personnel safety.

Complex retinal detachment treated with silicone oil or sulfur hexafluoride gas: a randomized clinical trial

BACKGROUND AND OBJECTIVE

To determine if either silicone oil or sulfur hexafluoride gas (SF6) is superior to the other in the treatment of complex retinal detachment after previously failed vitreous surgery.

PATIENTS AND METHODS

In this randomized clinical trial, 18 patients received treatment with silicone oil and 16 patients received SF6. The primary outcome was defined as successful anatomic attachment of the retina. Secondary outcomes included the time to retinal detachment, visual acuity, anatomic macular attachment, and any complications of surgery.

RESULTS

The odds of successful reattachment with silicone oil were 50% greater than they were with SF6, but this difference was not statistically significant. There were no differences between the two groups in any of the secondary outcomes.

CONCLUSIONS

This study did not have enough statistical power to detect a small but clinically important difference between the two treatment groups. Physicians must use their clinical judgment to select a vitreal substitute for complex retinal detachment when clinical trials are inconclusive. Data pooling is one method of overcoming the limitation of clinical trials with small sample sizes.

Risk factors for elevated intraocular pressure after the use of intraocular gases in vitreoretinal surgery

BACKGROUND AND OBJECTIVE

The authors studied the contribution of multiple factors, including gas type and concentration, to postoperative intraocular pressure (IOP) elevation following vitreoretinal surgery with intraocular gas.

PATIENTS AND METHODS

One hundred seventy-one eyes of 134 patients were retrospectively investigated after vitreoretinal surgery using air, sulfur hexafluoride (SF6) (10%-30%), or perfluoropropane (C3F8) (5%-35%).

RESULTS

IOPs greater than 25 mm Hg occurred in 74 of 171 eyes (43%). Elevated IOP was associated with increasing patient age (P < .001), expansile gas concentrations (P < .001), use of C3F8 (P = .01), and circumferential scleral buckles (P = .04). Most IOP elevations (65 eyes, 88%) occurred within 24 hours and responded to aqueous suppression within 24 to 72 hours.

CONCLUSIONS

Transient IOP elevation is common following vitreoretinal surgery. Although it is responsive to treatment, it may pose a risk to some eyes. Prophylactic treatment should be considered in high-risk eyes.