Characteristics of patients who had a stroke not initially identified during emergency prehospital assessment: a systematic review

Background

Around 25% of patients who had a stroke do not present with typical ‘face, arm, speech’ symptoms at onset, and are challenging for emergency medical services (EMS) to identify. The aim of this systematic review was to identify the characteristics of acute stroke presentations associated with inaccurate EMS identification (false negatives).

Method

We performed a systematic search of MEDLINE, EMBASE, CINAHL and PubMed from 1995 to August 2020 using key terms: stroke, EMS, paramedics, identification and assessment. Studies included: patients who had a stroke or patient records; ≥18 years; any stroke type; prehospital assessment undertaken by health professionals including paramedics or technicians; data reported on prehospital diagnostic accuracy and/or presenting symptoms. Data were extracted and study quality assessed by two researchers using the Quality Assessment of Diagnostic Accuracy Studies V.2 tool.

Results

Of 845 studies initially identified, 21 observational studies met the inclusion criteria. Of the 6934 stroke and Transient Ischaemic Attack patients included, there were 1774 (26%) false negative patients (range from 4 (2%) to 247 (52%)). Commonly documented symptoms in false negative cases were speech problems (n=107; 13%–28%), nausea/vomiting (n=94; 8%–38%), dizziness (n=86; 23%–27%), changes in mental status (n=51; 8%–25%) and visual disturbance/impairment (n=43; 13%–28%).

Conclusion

Speech problems and posterior circulation symptoms were the most commonly documented symptoms among stroke presentations that were not correctly identified by EMS (false negatives). However, the addition of further symptoms to stroke screening tools requires valuation of subsequent sensitivity and specificity, training needs and possible overuse of high priority resources.

Prehospital Transdermal Glyceryl Trinitrate for Ultra-Acute Intracerebral Hemorrhage: Data From the RIGHT-2 Trial

Supplemental Digital Content is available in the text.

Pilot trials suggest that glyceryl trinitrate (GTN; nitroglycerin) may improve outcome when administered early after stroke onset.

Management of acute ischaemic stroke in the acute medical unit

Ischaemic stroke is a major cause of death and disability which costs the NHS £2.8 billion/year. Acute stroke care is developing rapidly in line with an increasing evidence base. Intravenous thrombolysis is now recommended by NICE. For this guidance to be effectively implemented stroke must be viewed as a medical emergency by both the public and professionals. Emergency medical services must work in partnership with stroke services to establish systems and protocols which offer high quality acute stroke care. This provides challenges, both in systems design and delivery of clinical care.

Advanced nursing practice: an introduction to physical assessment

Changing philosophies of clinical management and moves to reduce junior doctors' hours have led to increasing pressure upon nurses to take on the responsibility for assessing and initiating the management of acutely ill patients. Although nurses have been educated to assess, plan, and deliver care in a format known as the nursing process, this does not fully equip them for the demands of their rapidly developing roles. With increased responsibility comes the risk of increased stress and legal accountability, particularly where inadequate support is provided. In an effort to address this matter, this article briefly considers the theory of gaining clinical expertise, and describes a framework to facilitate physical assessment.

Biomechanical examination of a commonly used measure of spasticity

BACKGROUND

An increase in the prevalence of neurological disability puts pressure on service providers to restrict costs associated with rehabilitation. Spasticity is an important neurological impairment for which many novel and expensive treatment options now exist. The antispastic effects of these techniques remain unexplored due to a paucity of valid outcome measures.

AIM

To develop a biomechanical measure of resistance to passive movement, which could be used in routine clinical practice, and to examine the validity of the modified Ashworth scale.

STUDY DESIGN

Repeated measure cross-section study on 16 subjects who had a unilateral stroke one-week previously and had no elbow contractures.

OUTCOME MEASURES

Simultaneous measurement of resistance to passive movement using a custom built measuring device and the modified Ashworth scale. Passive range of movement and velocity were also measured. The "catch", a phenomenon associated with the modified Ashworth scale, was identified by the assessor using a horizontal visual analogue scale and biomechanically quantified using the residual calculated from a linear regression technique.

RESULTS

Half the study population had a modified Ashworth score greater than zero. The association between the two measures was poor (kappa=0.366). The speed and range of passive movement were greater in subjects with modified Ashworth score "0" (P<0.05). Resistance to passive movement was higher in the impaired arm (P<0.05) and tended to decrease with repeated measures and increasing speeds.

CONCLUSIONS

A device to measure resistance to passive movement at the elbow was developed. The modified Ashworth scale may not provide a valid measure of spasticity but a measure of resistance to passive movement in an acute stroke population.

RELEVANCE

Spasticity is an important neurological impairment for which many novel and expensive treatment options are being made available. There is a paucity of clinically usable outcomes to measure spasticity. A device to measure resistance to passive movement at the elbow, which was more reliable than the modified Ashworth scale was developed. This device may provide a much needed objective clinical measure to evaluate the efficacy of antispasticity treatment.

Glenohumeral subluxation, scapula resting position, and scapula rotation after stroke: a noninvasive evaluation

OBJECTIVES

To determine whether scapular downward tilt (ScDT) and dynamic scapular lateral rotation (ScLR) in subjects with and without stroke is associated with subluxation, and to prove the reliability of a Scapula Locator System in an elderly population.

DESIGN

Repeated measures of ScLR by 2 observers.

SETTING

Outpatient rehabilitation department of a district general hospital.

PARTICIPANTS

To test device reliability, 5 healthy men (mean age +/- standard deviation, 72 +/- 5 yr). To test scapula position, 30 stroke patients (19 men, 11 women; mean age, 73 +/- 6 yr) and 15 healthy controls (12 men, 3 women; mean age, 62 +/- 6 yr).

INTERVENTIONS

The control subjects' ScDT was compared with stroke subjects' ScDT after stratification according to 3 patterns of ScLR symmetry and the presence of palpable glenohumeral subluxation.

MAIN OUTCOME MEASURES

For device reliability, 3-way analysis of variance. For scapula position, triangulated location by Scapula Locator System of acromion, inferior angle, and root of the scapular spine; then measurement of scapula motion to determine symmetry, lag, or lead.

RESULTS

The inter- and intraobserver reliability of the Scapula Locator System device was high (1% of variance each). Normal ScDT was positive (left side: 10.94 degrees +/- 2.62 degrees; right side: 9.69 degrees +/- 4.36 degrees ), indicating a downward-facing glenoid fossa. This finding was unchanged by stroke (10.46 degrees +/- 2.42 degrees ). All controls and 16 stroke subjects had symmetry between shoulders for ScLR rate and ScDT. Two other patterns (p <.01) of ScLR were found after stroke: 8 subjects had a slower rate of affected arm ScLR (lag) with a correspondingly greater ScDT on the affected side (2.61 degrees +/- 6.7 degrees ); 6 subjects had a faster rate of affected arm ScLR (lead) but with an upward-facing glenoid fossa on the affected side (ScDT: -11.84 degrees +/- 8.48 degrees ). No significant inter- or intrasubject difference in ScDT existed in the 6 cases of glenohumeral subluxation.

CONCLUSIONS

The scapula normally tilts downward with or without stroke. The effect of stroke is similar on tonic (ScDT) and phasic (ScLR) control of scapula position. Subluxation is not linked with a particular scapular resting position after stroke.

Electrical stimulation for preventing and treating post-stroke shoulder pain: a systematic Cochrane review

BACKGROUND

Shoulder pain after stroke is common and disabling. The optimal management is uncertain, but electrical stimulation (ES) is often used to treat and prevent pain.

OBJECTIVES

The objective of this review was to determine the efficacy of any form of surface ES in the prevention and/or treatment of pain around the shoulder at any time after stroke.

SEARCH STRATEGY

We searched the Cochrane Stroke Review Group trials register and undertook further searches of Medline, Embase and CINAHL. Contact was established with equipment manufacturers and centres that have published on the topic of ES.

SELECTION CRITERIA

We considered all randomized trials that assessed any surface ES technique (functional electrical stimulation (FES), transcutaneous electrical nerve stimulation (TENS) or other), applied at any time since stroke for the purpose of prevention or treatment of shoulder pain.

DATA COLLECTION AND ANALYSIS

Two reviewers independently selected trials for inclusion, assessed trial quality and extracted the data.

MAIN RESULTS

Four trials (a total of 170 subjects) fitted the inclusion criteria. Study design and ES technique varied considerably, often precluding the combination of studies. Population numbers were small. There was no significant change in pain incidence (odds ratio (OR) 0.64; 95% CI 0.19-2.14) or change in pain intensity (standardized mean difference (SMD) 0.13; 95% CI -1.0-1.25) after ES treatment compared with control. There was a significant treatment effect in favour of ES for improvement in pain-free range of passive humeral lateral rotation (weighted mean difference (WMD) 9.17; 95% CI 1.43-16.91). In these studies ES reduced the severity of glenohumeral subluxation (SMD -1.13; 95% CI -1.66 to -0.60), but there was no significant effect on upper limb motor recovery (SMD 0.24; 95% CI -0.14-0.62) or upper limb spasticity (WMD 0.05; 95% CI -0.28-0.37). There did not appear to be any negative effects of electrical stimulation at the shoulder.

REVIEWERS' CONCLUSIONS

The evidence from randomized controlled trials so far does not confirm or refute that ES around the shoulder after stroke influences reports of pain, but there do appear to be benefits for passive humeral lateral rotation. A possible mechanism is through the reduction of glenohumeral subluxation. Further studies are required.

Endograft planning without preoperative arteriography: a clinical feasibility study

PURPOSE

To investigate an alternative method of preprocedural planning for aortic endografting based solely on spiral computed tomography (CT) with 3-dimensional (3D) reconstruction without preoperative arteriography.

METHODS

From August 1997 to April 1998, 25 consecutive patients with abdominal aortic aneurysms (AAA) were evaluated for endovascular repair by spiral CT scans (2-mm slice thickness) and computerized 3D model construction. No additional imaging for planning was performed. The aortoiliac dimensions, thrombus load, calcification, and vessel tortuosity were measured and evaluated from the 3D model of the aortoiliac segment. These data were used for selecting the patients; the configuration, diameter, and length of the endograft; and the attachment sites for deployment.

RESULTS

Primary procedural success was 92% (23/25). All endografts were deployed as planned, and there were no conversions to open repair. Six patients required adjunctive procedures for delivery system access or for iliac aneurysm exclusion, as predicted by the 3D model. Mean procedural time was 91 minutes (range 24 to 273). Two (8%) type II (side branch) endoleaks both sealed spontaneously within 1 month. No graft-related complications or death occurred, for a 30-day technical success rate of 100%.

CONCLUSIONS

This computerized 3D model provided accurate data for preoperative evaluation of the aortoiliac segment for endovascular AAA repair. Satisfactory technical outcomes for aortic endografts can be achieved without the use of preprocedural invasive imaging.

Electrical stimulation for preventing and treating post-stroke shoulder pain

BACKGROUND

Shoulder pain after stroke is common and disabling. The optimal management is uncertain, but electrical stimulation (ES) is often used to treat and prevent pain.

OBJECTIVES

The objective of this review was to determine the efficacy of any form of surface ES in the prevention and / or treatment of pain around the shoulder at any time after stroke.

SEARCH STRATEGY

We searched the Cochrane Stroke Review Group trials register and undertook further searches of MEDLINE, EMBASE and CINAHL. Contact was established with equipment manufacturers and centres that have published on the topic of ES.

SELECTION CRITERIA

We considered all randomised trials that assessed any surface ES technique (functional electrical stimulation (FES), transcutaneous electrical nerve stimulation (TENS) or other), applied at any time since stroke for the purpose of prevention or treatment of shoulder pain.

DATA COLLECTION AND ANALYSIS

Two reviewers independently selected trials for inclusion, assessed trial quality and extracted the data.

MAIN RESULTS

Four trials (a total of 170 subjects) fitted the inclusion criteria. Study design and ES technique varied considerably, often precluding the combination of studies. Population numbers were small. There was no significant change in pain incidence (Odds Ratio (OR) 0.64; 95% CI 0.19 to 2.14) or change in pain intensity (Standardised Mean Difference (SMD) 0.13; 95% CI -1.0 to 1.25) after ES treatment compared to control. There was a significant treatment effect in favour of ES for improvement in pain-free range of passive humeral lateral rotation (Weighted Mean Difference (WMD) 9.17; 95% CI 1.43 to 16.91). In these studies ES reduced the severity of glenohumeral subluxation (SMD -1.13; 95% CI -1.66 to -0.60), but there was no significant effect on upper limb motor recovery (SMD 0.24; 95% CI -0.14 to 0.62) or upper limb spasticity (WMD 0.05; 95% CI -0.28 to 0.37). There did not appear to be any negative effects of electrical stimulation at the shoulder.

REVIEWER'S CONCLUSIONS

The evidence from randomised controlled trials so far does not confirm or refute that ES around the shoulder after stroke influences reports of pain, but there do appear to be benefits for passive humeral lateral rotation. A possible mechanism is through the reduction of glenohumeral subluxation. Further studies are required.

Active and passive scapulohumeral movement in healthy persons: a comparison

OBJECTIVES

Clinical studies investigating shoulder complaints have found that active exercises and passive manipulation are not equally effective treatments, perhaps because active and passive movements align the individual shoulder girdle components differently. This study sought to investigate whether a significant difference exists in scapulohumeral rhythm of the healthy shoulder when the humerus is elevated actively or passively.

STUDY DESIGN

Both shoulders of 10 healthy volunteers (9 men; mean age 50 yrs) were studied using an electromagnetic coordinate system to locate the position of the scapula relative to the humerus and trunk. Scapula position in three dimensions was recorded at 10 degrees intervals during active and passive humeral elevation in the coronal plane between 10 degrees and 50 degrees. Each shoulder was measured three times.

RESULTS

Analysis of variance showed that in all three planes of scapula movement (lateral rotation, backward tip, and retraction) the components of variance attributable to the differences in active and passive movement were less than 5%.

CONCLUSIONS

During humeral elevation between 10 degrees and 50 degrees no significant difference exists between active and passive shoulder complex motion in healthy individuals. These findings may help to explain why passive manipulation is an effective treatment for shoulder complaints.

A review of the properties and limitations of the Ashworth and modified Ashworth Scales as measures of spasticity

BACKGROUND

The Ashworth Scale and the modified Ashworth Scale are the primary clinical measures of spast city. A prerequisite for using any scale is a knowledge of its characteristics and limitations, as these will play a part in analysing and interpreting the data. Despite the current emphasis on treating spasticity, clinicians rarely measure it.

OBJECTIVES

To determine the validity and the reliability of the Ashworth and modified Ashworth Scales.

STUDY DESIGN

A theoretical analysis following a structured literature review (key words: Ashworth; Spasticity; Measurement) of 40 papers selected from the BIDS-EMBASE, First Search and Medline databases.

CONCLUSIONS

The application of both scales would suggest that confusion exists on their characteristics and limitations as measures of spasticity. Resistance to passive movement is a complex measure that will be influenced by many factors, only one of which could be spasticity. The Ashworth Scale (AS) can be used as an ordinal level measure of resistance to passive movement, but not spasticity. The modified Ashworth Scale (MAS) will need to be treated as a nominal level measure of resistance to passive movement until the ambiguity between the '1' and '1+' grades is resolved. The reliability of the scales is better in the upper limb. The AS may be more reliable than the MAS. There is a need to standardize methods to apply these scales in clinical practice and research.

Can stroke patients use visual analogue scales?

BACKGROUND AND PURPOSE

Visual analogue scales (VAS) have been used for the subjective measurement of mood, pain, and health status after stroke. In this study we investigated how stroke-related impairments could alter the ability of subjects to answer accurately.

METHODS

Consent was obtained from 96 subjects with a clinical stroke (mean age, 72.5 years; 50 men) and 48 control subjects without cerebrovascular disease (mean age, 71.5 years; 29 men). Patients with reduced conscious level or severe dysphasia were excluded. Subjects were asked to rate the tightness that they could feel on the (unaffected) upper arm after 3 low-pressure inflations with a standard sphygmomanometer cuff, which followed a predetermined sequence (20 mm Hg, 40 mm Hg, 0 mm Hg). Immediately after each change, they rated the perceived tightness on 5 scales presented in a random order: 4-point rating scale (none, mild, moderate, severe), 0 to 10 numerical rating scale, mechanical VAS, horizontal VAS, and vertical VAS. Standard tests recorded deficits in language, cognition, and visuospatial awareness.

RESULTS

Inability to complete scales with the correct pattern was associated with any stroke (P<0.001). There was a significant association between success using scales and milder clinical stroke subtype (P<0.01). Within the stroke group, logistic regression analysis identified significant associations (P<0.05) between impairments (cognitive and visuospatial) and inability to complete individual scales correctly.

CONCLUSIONS

Many patients after a stroke are unable to successfully complete self-report measurement scales, including VAS.

Experiences of volunteer patients during undergraduate examinations: printed information can lead to greater satisfaction

BACKGROUND

Whilst most patients are happy to participate in medical examinations, previous studies have shown that some are dissatisfied with the information that they receive beforehand.

OBJECTIVES

To demonstrate that patient satisfaction can be improved by the provision of written information.

METHODS

Thirty-seven patients attending the final MBBS examination were sent written information about what to expect. The patients' experiences were assessed by means of an anonymous postal questionnaire 1 week after the examination. Their satisfaction with the level of information received beforehand was compared with that of an historical cohort who had received no written information.

RESULTS

The patients had few complaints about their experience of participating in examinations and many enjoyed it. Only 5% of patients registered dissatisfaction with the level of information that was provided, compared with 18% in the previous study (P = 0.077).

CONCLUSIONS

Written information led to a (near significant) improvement in patients satisfaction when compared to a previous cohort. We recommend that all patients attending for medical examinations should be provided with written information.

Associated injuries in patients with blunt chest trauma: detection by abdominal roentgenograms after aortography

To determine the value of abdominal roentgenograms after aortography for detecting additional organ injuries, we retrospectively evaluated the abdominal and pelvic roentgenograms after aortography of 170 trauma patients who underwent arch aortography to detect aortic rupture. In 160 (94%) of 170 patients, the results of arch studies were normal. Ten (6%) of 170 patients had aortic rupture (8 patients) or rupture of a major vessel (2 patients). Thirty-one (18%) of 170 patients had associated injuries demonstrated by the roentgenograms taken after aortography, including pelvic or femoral fractures (13%), pelvic hematomas (5.8%), renal injuries (1.1%), and bladder ruptures (2.9%). We conclude that abdominal and pelvic pain roentgenograms should be part of a routine arch aortography performed for blunt chest trauma to detect additional organ injuries that frequently accompany injuries from motor vehicle crashes.

Endoscopic transaxillary subpectoral breast augmentation

The transaxillary approach to breast augmentation is an established technique that offers the advantage of a remote incision in an aesthetically acceptable area. The main disadvantage to this approach is the lack of visualization of the implant pocket, necessitating blind, blunt dissection of the pectoral muscle origins. Occasionally, this limitation may result in improper implant placement and poor aesthetic results. In order to address this shortcoming, we have explored the use of minimally invasive endoscopic techniques in transaxillary augmentation to allow division of the pectoral muscle origin under direct visualization, effectively lowering the inframammary crease. Initial dissections and instrument development were performed in five unpreserved female cadavers. Subsequently, 103 implants have been placed in 53 patients utilizing the endoscopic transaxillary approach. Follow-up ranges from 2 weeks to 20 months. There have been no hematomas, infections, capsular contractures, or other complications. Aesthetic results have been good, and patient acceptance is high. By providing predictable and reproducible control of the inframammary crease, endoscopic dissection has allowed us to expand our indications for the transaxillary approach to breast augmentation. Surgical technique and brief clinical experience are described.

Liposome encapsulation: a method for enhancing the effectiveness of local antibiotics

BACKGROUND

Treatment of contaminated surgical wounds is often complicated by the failure of local or systemic antibiotic treatment and prophylaxis. Locally administered liposome-encapsulated antimicrobials may offer advantages over free antibiotics, including an increase in efficacy, ease of administration, and safety. The therapeutic advantages, as well as the absorption and distribution of locally administered liposome-encapsulated antibiotics, were compared with those of locally applied unencapsulated antibiotics in a contaminated wound model.

METHODS

Anesthetized rats had a 1 cm incision over the midback that was inoculated with 10(8) colony-forming units Pseudomonas aeruginosa (group 1; n = 102) or left uninfected (group 2; n = 35). Before wound closure, infected animals were treated with a local application of 0.3 ml saline solution (untreated; n = 30), 5.5 mg tobramycin in 0.3 ml saline solution (free tobramycin; n = 30), or 0.3 ml liposome-encapsulated tobramycin (LET; n = 42). Animals were killed 24, 48, and 72 hours after operation; serum and tissue tobramycin concentrations and tissue quantitative cultures were studied. Liposomes were radiolabeled to examine organ distribution.

RESULTS

The data show that LET produced sustained local concentrations of antibiotic compared with free drug; sustained concentration prolonged the antimicrobial effect despite a single dose of antibiotic. LET reduced tissue bacterial counts to a greater extent and for a longer period of time than free tobramycin. The presence of infection further reduced clearance of LET from the infected site.

CONCLUSIONS

The liposomal delivery of local antibiotics in this model of surgical wound infection reduced the number of organisms more effectively than locally applied free drug. Animals treated with LET had consistently less than the 10(5) organisms per gm tissue considered critical for invasive infection, suggesting that liposomal antibiotics may be clinically useful in surgical wound prophylaxis.

Liposome delivery of aminoglycosides in burn wounds

The current study evaluated the pharmacodynamics of topically applied antimicrobials incorporated into radiolabeled liposomes. Radiolabeled 125I-phenyldecanoic acid was used in the formulation of small unilamellar liposomes. Sephadex (cross-linked dextran beads) G-50 columns were run to determine the per cent of radioactivity incorporated into liposomes and persistence of radioactive tag on the liposome after two weeks (greater than 95 per cent) remained incorporated. On the day of the experiment, 31 adult Sprague Dawley rats were subjected to a 10 per cent total body surface area full thickness burn (Walker burn model). All rats were treated with topical application of 0.3 milliliters of tobramycin entrapped in 125I-liposomes, and burn wounds were covered with Opsite (Winfield Laboratories). This formulation resulted in each rat receiving 14 milligrams per kilogram of tobramycin with a specific activity of 10.41 microcuries. Rats were sacrificed at several time periods after burn injury (nine after 24 hours, 12 after 48 hours, 11 after 72 hours). At these time intervals, serum and tissue tobramycin levels were measured, burn dressing, burn tissue and splanchnic organs were harvested and radioactivity was assessed with a gamma scintillation counter to determine tissue concentration of 125I-liposome tobramycin. Concentration of tobramycin in the serum was negligible at 24, 48 and 72 hours postburn, but was significant in the burn tissues at these times. The radioactive recovery data demonstrated that the majority (greater than 90 per cent) of the recovered liposomes remained at the site of application (the burn wound). No splanchnic organs had greater than 2 per cent of the recovered 125I-liposomes at any time period. These data suggest that, in burn wounds, tobramycin incorporated into liposomes remain at the site of initial application, resulting in high local concentrations with little systemic absorption and confirm that liposomes provide an effective vehicle for delivery of antimicrobials at the site of the burn injury.

Topical liposomal delivery of antibiotics in soft tissue infection

A new drug delivery system (lipid microcarriers) was studied in an experimental model of infected soft tissue wounds. Superficial, nonlethal infection was produced in the adult rat by injecting 1 ml containing 10(8) colony-forming units (CFU) of Pseudomonas aeruginosa under the superficial fascia of the paraspinus muscle of a 2-cm2 excised wound. All wounds were dressed with N-Terface, a nonadherent wound material, and covered with Kontor sponge, an open-cell polyurethane sponge containing either normal saline (group I), free tobramycin (groups III and V), liposome-entrapped tobramycin (groups II and IV), silver sulfadiazene (group VI), or liposome-entrapped silver sulfadiazene (group VII). At 24, 48, and 72 hr postinjection, animals were sacrificed and colony-forming units of P. aeruginosa per gram of muscle tissue were determined. Group I had significantly higher colony-forming units of P. aeruginosa per gram than groups II and III at 48 and 72 hr and than groups IV and V at all times. One single dose of liposome-encapsulated silver sulfadiazine significantly decreased bacterial counts compared to untreated controls and, to a similar extent, compared to multiple applications of free drug. Colony-forming units in all treatment groups (II and III, IV and V, VI and VII) were similar at all time periods within equivalent dosages. The ability of one application of liposomal-entrapped antibiotics to result in a therapeutic effect that requires multiple applications of topically applied free antibiotics offers potential clinical advantages.

Enhanced effectiveness of intraperitoneal antibiotics administered via liposomal carrier

The local application of antibiotics to treat intraperitoneal contamination has been used with variable results. Liposomes are not rapidly absorbed from the peritoneal cavity, offering a potential delivery system for intraperitoneal antibiotics. The effects of liposome-incorporated antibiotic administration in a fecal peritonitis model were compared with the effects of conventional intraperitoneal and intramuscular antibiotics. Rats were divided into four groups: untreated, intramuscular cefoxitin, intraperitoneal cefoxitin, and intraperitoneal liposome-incorporated cefoxitin. Quantitative blood cultures were drawn at 4 and 24 hours. Liposome delivery of cefoxitin significantly reduced mortality and bacteremia at 4 and 24 hours compared with control subjects and conventional antibiotic groups. Peritoneal abscess formation tended to decrease in the liposome antibiotic group (mean +/- SEM, 6.86 +/- 0.79) compared with the group receiving free intraperitoneal administration of antibiotics (10.33 +/- 1.63). We conclude that liposomal delivery significantly enhances the effectiveness of cefoxitin in this model of peritonitis.

Ultrasound detection of differences in density. Explanation of the ureteric jet phenomenon and implications for new ultrasound applications

Flow of urine from the ureter into the bladder can be encountered during routine sonographic examination of the pelvis. The findings include a stream of hyperechogenic foci spurting into the bladder in real time with the production of a frequency shift during Doppler examination. We have demonstrated that visualization of this phenomenon, at least in part, reflects differences in density and associated compressibility changes between urine in the bladder and in the ureter, and need not be dependent upon flow velocity or other previously hypothesized parameters. The clinical utility of these reproducible and measurable phenomena is explored.