Implementation of point-of-care ultrasonography in an infectious disease ward

INTRODUCTION

Point-of-care ultrasonography (POCUS) has emerged as an essential supplement to physical examination in many specialties. In contrast, its use by infectious diseases (ID) specialists remains anecdotal. Here, we report on the acquisition of an ultrasonography device in a French ID ward, and we describe its everyday use.

METHODS

A preliminary audit was conducted to evaluate the potential impact of the acquisition of an ultrasonography device. A second audit was performed during the first year following the acquisition of the device to quantify its everyday use. We also evaluated the impact of POCUS implementation on medical imaging requests by comparing the number of intra-hospital transports before and after the acquisition.

RESULTS

According to the first audit, 81 of the 199 (41%) imaging examinations that were prescribed during a two-month period could have been replaced by POCUS. During the first year following the acquisition of the ultrasonography device, POCUS was performed 240 times by 31 different operators. The operators were a senior physician, an intern, and a medical student in 94 (39%), 135 (57%), and 11 (5%) cases, respectively. The organs most frequently explored were the genito-urinary tract (n=74), the joints (n=35), and the lungs/pleura (n=35). Acquisition of the device was followed by a significant decrease in the number of transports to the ultrasonography room, whereas the total number of transports to the medical imaging ward did not change.

CONCLUSION

Opportunities to use POCUS in the ID ward are numerous. POCUS training should be part of the ID specialist's curriculum.

Validation of the Oral Survey-B System for Electronic Data Capture in National Oral Health Surveys

The aims of the present study were to incorporate and to validate the electronic capture of participant-related outcomes into the Oral Survey-B System, which was originally developed for the electronic capture of clinical data. The validation process compared the performances of electronic and handwritten data captures. The hypothesis of noninferiority would be established if participants performed electronic data capture of the questionnaire survey with an effectiveness of at least 95% of that of handwritten data capture. In this multicenter, randomized, one-period crossover study design, participants (n = 261) were allocated to start with either electronic or handwritten data capture. The incorporation of the electronic self-completed questionnaire into the Oral Survey-B System was successful. The validation of the electronic questionnaire was performed by participants aged from 18 to 75 years. The interrater reliability of participants performing electronic and handwritten data capture of nonclinical assessments per questionnaire and per entry showed a kappa value of 0.72 (95% CI: 0.53-0.94). The noninferiority of electronic data capture in relation to that of the handwritten data capture and transfer was shown (p < 0.0001; 95% CI: 1.47-2.99). In conclusion, the electronic capture of participant-related outcomes with the Oral Survey-B System, originally designed for capture of clinical data, was validated. The electronic data capture was accurate and limited the number of errors. The participants were able to perform electronic data capture effectively, supporting its implementation in further National Oral Health Surveys. With the consideration of participant preference and time savings, this could lead to the implementation of electronic data capture worldwide in National Oral Health Surveys.

Resistance of the Burkholderia cepacia complex to fosmidomycin and fosmidomycin derivatives

The Burkholderia cepacia complex (BCC) is a group of 17 closely related opportunistic pathogens that are able to infect the respiratory tract of cystic fibrosis patients. BCC bacteria are intrinsically resistant to many antibiotics and are therefore difficult to eradicate. Fosmidomycin could be a new therapeutic agent to treat BCC infections as it inhibits 1-deoxy-d-xylulose-5-phosphate reductoisomerase (Dxr), a key enzyme in the non-mevalonate pathway essential in BCC bacteria for isoprenoid synthesis. In this study, the antimicrobial activity of fosmidomycin and eight fosmidomycin derivatives towards 40 BCC strains was investigated. All BCC strains were resistant to fosmidomycin, although addition of glucose-6-phosphate reduced the minimum inhibitory concentration values of FR900098, the fosmidomycin acetyl derivative, from 512 mg/L to 64 mg/L for Burkholderia multivorans and B. cepacia. This enhanced activity was linked to increased expression of the genes involved in glycerol-3-phosphate transport, which appears to be the only route for fosmidomycin import in BCC bacteria. Furthermore, upregulation of a fosmidomycin resistance gene (fsr) encoding an efflux pump was observed during fosmidomycin and FR900098 treatment. These results strongly suggest that the observed resistance in BCC bacteria is due to insufficient uptake accompanied by fosmidomycin and FR900098 efflux.

Lateral asymmetries in attentional priming during a semantic and a visuospatial task

This study tests the hypothesis that lateral cueing of attention activates the contralateral hemisphere and also that performance on a semantic and a visuospatial task will differentially be affected depending on the visual field (right or left) to which attention was drawn. In an experimental setting, 68 subjects performed both a semantic and a visuospatial discriminating task, whereby visual priming signals unbeknownst were presented to either the left or the right visual field. For the semantic task (which is believed to engage primarily the left hemisphere) priming signals enhanced performance more when they were presented to the right visual field. For the visuospatial task, no difference was found between priming signals presented in either visual field. While there may be several alternative explanations for the observed difference in the effects of the priming signals presented to different visual fields, the importance of separating the components inherent in the tasks is stressed. While the process of decision-making may involve different relative activation of the two hemispheres, depending on whether the stimuli are semantic or visuospatial in nature, performance on the task also involves manual coordination which will depend especially on motor activation in the left hemisphere.

Relationship between attentional orientation and associative learning

This study presents experimental evidence for a relationship between attentional orientation and associative learning. Learning to establish contingencies between warning signals and subsequent task stimuli is a phenomenon which we know from previous studies to be more associated with the left hemisphere. We investigated how hemispheric priming, i.e., activating one hemisphere by directing attention towards the contralateral hemispace, affected both the rate and the extent of associative and nonassociative learning. When attention was directed towards the right while perceiving a discrimination task stimulus, the rate of learning through contingency formation was increased since the relative activation of the left hemisphere was increased. Such a relationship was not found for relative activation of the right hemisphere following leftward orientation of attention.

A comparison of left ventricular performance indices measured by transesophageal echocardiography with automated border detection

BACKGROUND

Automated border detection (ABD) allows semiautomated measurement of left ventricular (LV) areas. They can be combined with left ventricular pressure signals to generate pressure-area loops and pressure-dimension indices of contractility. This study compared conventional indices of ventricular performance (fractional area change [FAC] and circumferential fiber shortening [Vcfc]) with pressure-dimension indices of contractility. A secondary aim was to compare the effects of volatile anesthetics on the indices.

METHODS

Using transesophageal echocardiography with automated border detection, FAC and Vcfc were obtained in 23 patients after cardiopulmonary bypass. Left ventricular pressures were obtained with a left ventricular catheter. Preload reduction by inferior vena caval occlusion was used to obtain end-systolic elastance (Ees), preload recruitable stroke force (PRSF), and dP/dtmax x EDA(-1) (EDA = end-diastolic area). In 11 patients, the measurements were repeated at 1 end-tidal minimum alveolar concentration of halothane or isoflurane. The results are expressed as mean +/- SD.

RESULTS

After cardiopulmonary bypass, FAC was 31.1+/-7.9%, Vcfc was 0.6+/-0.2 circ x s(-1), Ees was 25.8+/-11.6 mmHg x cm(-2), PRSF was 60.8+/-26.6 mmHg, and dP/dtmax x EDA(-1) was 245+/-123.4 mmHg x s(-1) x cm(-2). At 1 minimum alveolar concentration of a volatile anesthetic agent, FAC, Vcfc, and dP/dtmax x EDA(-1) remained unchanged. Significant decreases in Ees (19%) and PRSF (28%) were observed.

CONCLUSIONS

The association between pressure-dimension indices and Vcfc or FAC was weak or nonexistent. A reduction in myocardial contractility induced by the administration of volatile anesthetic agents was detected by Ees and PRSF, but not by FAC, Vcfc, or dP/dtmax x EDA(-1). After myocardial revascularization, Ees and PRSF appear more sensitive than FAC or Vcfc for measuring changes in contractility.

An algorithm for real-time, continuous evaluation of left ventricular mechanics by single-beat estimation of arterial and ventricular elastance

We describe a computer algorithm that allows continuous, real-time evaluation of ventricular elastance (Ees), arterial elastance (Ea), and their coupling ratio in a clinical setting. In the conventional pressure-volume analysis of left ventricular (LV) contractility, invasive methods of volume determination and a significant, rapid preload reduction are required to generate Ees. With the help of automated border detection by transesophageal echocardiography, and a technique of estimating peak LV isovolumic pressure, Ea and Ees were determined from a single cardiac beat without the need for preload reduction. A comparison of results obtained by a conventional approach and the new algorithm technique, showed good correlation for Ea (r = 0.86, p < 0.001) and Ees (r = 0.74, p = 0.001). Bias analysis showed a bias (d) of 1.47 mmHg/cm2 for Ea with a standard deviation (SD) of 7.03 mmHg/cm2, and upper (d+2SD) and lower(d-2SD) limits of agreement of 15.24 mmHg/cm2 and -12.31 mmHg/cm2, respectively. Bias analysis showed a bias of -1.42 mmHg/cm2 for Ees with a SD of 4.88 mmHg/cm2, and limits of agreement of 8.15 mmHg/cm2 and -10.98 mmHg/cm2. The algorithm's stability to artifacts was also analyzed by comparing magnitudes of residuals of Ea and Ees from source signals with and without noise. With Ea differing by an average of 1.036 mmHg/cm2 and Ees differing by an average of 0.836 mmHg/cm2, the algorithm was found to be stable to artifacts in the source signals.

Left ventricular systolic and diastolic function in septic shock

OBJECTIVE

The identification of myocardial dysfunction in septic shock has not yet been fully elucidated. We therefore studied patients with persistently vasopressor-dependent septic shock, both with invasive haemodynamic monitoring and transoesophageal two-dimensional and Doppler echocardiography (TEE).

DESIGN

Prospective study.

SETTING

General ICU in University Hospital.

PATIENTS AND METHODS

All patients were monitored with arterial and pulmonary artery catheters. Haemodynamics were obtained concomitantly with TEE measurements. TEE was performed at three levels: a) a midpapillary short axis view of the left ventricle (LV) in order to measure end-systolic and end-diastolic areas; b) at the level of both the mitral valve for early (E) and late (A) filling parameters and c) the level of the right upper pulmonary vein for systolic (S) and diastolic (D) filling characteristics. Each parameter was characterised by maximal flow velocity and time velocity integral.

RESULTS

Although the measurements of cardiac index demonstrated a wide range, three subsets of patients were identified post hoc after analysis on the basis of different Doppler patterns: first, patients with a LV without regional wall motion abnormalities and both E/A and S/D greater than 1 (group 1); second, patients with a comparable haemodynamic condition, apparently normal LV systolic function but with altered Doppler patterns: S/D less than 1 in conjunction with E/A more than 1 (group 2); finally, patients with compromised global LV systolic function, E/A less than 1 and S/D less than (group 3).

CONCLUSIONS

Notwithstanding the known various interfering factors which limit the broad applicability of TEE to determine LV function in septic shock, our data suggest that cardiac dysfunction in septic shock shows a continuum from isolated diastolic dysfunction to both diastolic and systolic ventricular failure. These data strengthen the need of including the evaluation of pulmonary venous Doppler parameters in each investigation in order to obtain supplementary information to interpret diastolic function of the LV in septic shock patients.

Cholinesterase reactivation in organophosphorus poisoned patients depends on the plasma concentrations of the oxime pralidoxime methylsulphate and of the organophosphate

We measured in nine patients, poisoned by organophosphorus agents (ethyl parathion, ethyl and methyl parathion, dimethoate, or bromophos), erythrocyte and serum cholinesterase activities, and plasma concentrations of the organophosphorus agent. These patients were treated with pralidoxime methylsulphate (Contrathion), administered as a bolus injection of 4.42 mg.kg-1 followed by a continuous infusion of 2.14 mg.kg-1/h, a dose regimen calculated to obtain the presumed "therapeutic" plasma level of 4 mg.l-1, or by a multiple of this infusion rate. Oxime plasma concentrations were also measured. The organophosphorus agent was still detectable in some patients after several days or weeks. In the patients with ethyl and methyl several days or weeks. In the patients with ethyl and methyl parathion poisoning, enzyme reactivation could be obtained in some at oxime concentrations as low as 2.88 mg.l-1; in others, however, oxime concentrations as high as 14.6 mg.l-1 remained without effect. The therapeutic effect of the oxime seemed to depend on the plasma concentrations of ethyl and methyl parathion, enzyme reactivation being absent as long as these concentrations remained above 30 micrograms.l-1. The bromophos poisoning was rather mild, cholinesterases were moderately inhibited and increased under oxime therapy. The omethoate inhibited enzyme could not be reactivated.