Evaluation of a novel in-line point-of-care blood gas analyser.

Point-of-care testing is becoming increasingly relevant to the practice of anaesthesia and critical care medicine, especially in terms of minimisation of sample volumes and decreased time to decision making. We performed a prospective observational study to evaluate a novel, in-line blood gas analysis device against a conventional benchtop model, and assessed it while placing the enrolled patients under extreme physiological conditions, specifically deep hypothermic circulatory arrest. Eight patients were studied, and had between seven and 11 samples analysed for seven variables (pH, pCO2 , pO2 , HCO3 (-) , base excess [BE], K(+) and haematocrit [Hct]), using the device during the process of cooling to 20 °C on cardiopulmonary bypass, and subsequent rewarming to normothermia. After Passing-Bablok analysis, the variables were evaluated for bias, limits of agreement and percentage error at above and below 30 °C. Of the measured variables, only pH (percentage error 2.4%) and potassium (19.8%) demonstrated acceptable (< 30%) percentage error over the full range of temperatures measured. Carbon dioxide, when stratified by temperature, was acceptable (< 30 °C percentage error 24.6%, > 30 °C percentage error 9.9%), but the overall percentage error of the dataset (45.8%) was excessively high. Bicarbonate and haematocrit both had an acceptable percentage error above 30 °C (25.2% and 18.5%, respectively), but similar to carbon dioxide, percentage error for the full range of temperatures exceeded 30%. These data differ from previous work examining this device, and highlights the difference between derived measures using different apparatuses when exposed to extreme physiological conditions.

Asymmetry of voice onset time-processing in adult developmental dyslexics.

OBJECTIVE: The human auditory cortex codes speech temporally according to sequential acoustico-phonetic cues like the voice onset time (VOT). This coding is predominantly left-lateralized in normal readers. We examined VOT-processing asymmetries in adults with a history of developmental dyslexia (DD-history+). METHODS: Auditory-evoked potentials (AEPs) to voiced (/ba/) and voiceless (/pa/) speech stimuli were recorded from 10 DD-history+ adults and 8 controls. Source modelling of the "release component" (RC: approximately 240 ms; time-locked to voiced consonantal release and considered reflective of VOT-processing) was conducted to explore VOT asymmetries. RESULTS: Controls demonstrated L>R RC source probe amplitude asymmetry in the auditory cortex. DD-history+ subjects with little persistent reading deficit (n=5) demonstrated normal temporal coding but rightward asymmetry. DD-history+ subjects with severe persistent deficits (n=5) exhibited numerous supplemental AEP components (notably left hemispheric) and inconsistent asymmetry (leftward or alternating). CONCLUSIONS: These preliminary findings suggest that DD-history+ adults process auditory speech cues differently than adults without previous DD. The nature of this processing may relate to the severity of persistent reading deficits. SIGNIFICANCE: Previous dyslexics with little persistent deficit can exhibit atypical functional asymmetry with normal auditory temporal coding. Source modelling represents an effective, non-invasive means of exploring processing asymmetries in clinical populations.

Is biolectrical impedance analysis a tool at bedside, during heat waves to assist geriatricians with discriminative diagnosis of hypertonic dehydration?

OBJECTIVES: To assess BIA data given by Analycor 3 and some bio-impedance equations to assist geriatricians with discriminative diagnosis of hypertonic dehydration, during heat waves. DESIGN: Prospective study: a dehydrated patients group has been compared with a randomised control group. SETTING: The study was carried out in a French geriatric department, in the Emile Roux geriatric hospital. PARTICIPANTS: 36: six men and twelve women in each group. MEASUREMENTS: The most valuable clinical indicators of dehydration severity were recorded and scored. BIA measurements were performed with an Analycor 3 analyzer; TBW was calculated from impedances at 50 and 100 kHz, ECW from impedance at 5 kHz; Calculations were made also with formula described in the literature, validated in healthy or in institutionalised elderly subjects. RESULTS: TBW and ECW values were always lower in dehydrated group than in control group, but without significance, whatever the applied formula; however ICW values calculated with "manufacturers equations" significantly decreased in dehydrated group. Data given by the analyzer used in this study, as well as BIA age specific equations discriminated the severely hypertonic dehydrated patients sub-group, but not the mildly hypertonic dehydrated patients sub-group. CONCLUSION: The BIA data given by the analyzer used in this study assist geriatricians at bedside with discriminative diagnosis of hypertonic dehydration, especially in severe hypertonic dehydration, but data given by the analyzer used in this study, as well as age specific equations are sometimes in poor agreement with clinical and biological parameters usually selected to assess dehydration, in mildly dehydrated patients.

Ictal asomatognosia with hemiparesis.

A 69-year-old woman presented with an ictal Anton-Babinski syndrome (asomatognosia with hemiparesis). Except for head and eye deviation to the side of the paralyzed limb, epileptic nystagmus, brief episodes of impaired consciousness, and automatisms, clinical symptomatology was identical to Anton-Babinski syndrome of vascular origin. Results of MRI imaging were normal. EEG showed a simple partial nonconvulsive status epilepticus of right parieto-temporal origin. Anton-Babinski syndrome may thus be a functional expression of focal status epilepticus.

Intracerebral evoked potentials in pitch perception reveal a functional asymmetry of the human auditory cortex.

One acoustic feature that plays an important role in pitch perception is frequency. Studies on the processing of frequency in the human and animal brain have shown that the auditory cortex is tonotopically organized: low frequencies are represented laterally whereas high frequencies are represented medially. To date, the study of the functional organization of the human auditory cortex in the processing of frequency has been limited to the use of either scalp-recorded auditory evoked potentials (AEPs), which have relatively poor spatial resolving power, or functional imagery techniques, which have poor temporal resolving power. The present study uses intracerebrally recorded AEPs to explore this topic in the primary and secondary auditory cortices of both hemispheres of the human brain. Recordings were carried out in 45 adult patients with drug-resistant partial seizures. In the right hemisphere, clear spectrally organized tonotopic maps were observed with distinct separations between different frequency-processing regions. AEPs for high frequencies were recorded medially, whereas AEPs for low frequencies were recorded laterally. In the left hemisphere, however, this tonotopic organization was less evident, with different regions involved in the processing of a range of frequencies. The hemisphere-related difference in the processing of tonal frequency is discussed in relation to pitch perception.

[Oral anticoagulation in older patients. Establishment and validation of a new posologic warfarin regimen]. / Anticoagulation orale du sujet âgé. Etablissement et validation d'une grille d'adaptation posologique de la warfarine.

OBJECTIVE: Warfarin is highly effective in preventing thromboembolism and more recent clinical trials have established that adjusted dosing is highly effective in reducing the risk of ischemic stroke in patients with nonvalvular atrial fibrillation. Fear of major hemorrhage frequently dissuades physicians from use of anticoagulants in older people. In addition, the time needed to reach the therapeutic range may be excessively long and delicate in this population. PATIENTS AND METHODS: This study was undertaken in two phases. In the first phase, 20 patients (mean age 84 years) were given 5 mg of warfarin once daily for 3 consecutive days. During the following days, the dose of warfarin was adjusted to reach an International Normalized Ratio (INR) in the therapeutic range (between 2 and 3). The good correlation (r = -0.77, p < 0.01) between the INR on day 4 and the daily maintenance dose was used to establish an algorithm to predict the maintenance dose of warfarin. In the second phase, this algorithm was successfully tested in 94 elderly patients, mean age 84 years (range 74-99). RESULTS: The predicted dose on day 4 was effective in 56% within +/- 0.5 mg and in 92% within +/- 1 mg of the original predicted dose. No hemorrhagic complication occurred during the study. The therapeutic range was reached on day 4 in 63.5% and on day 1 in 91% of the patients. CONCLUSION: We have developed a method of predicting the maintenance dose of warfarin in a very old population based on the INR. This method is safe and easy to use.

[Predictive factors of acquired methicillin-resistant Staphylococcus aureus in a rehabilitation care unit]. / Facteurs prédictifs d'acquisition du Staphylococcus aureus résistant à la méticilline dans un service de soins de suite et de réadaptation.

UNLABELLED: Controlling the diffusion of multiresistant bacteria is a priority in the campaign against nosocomial infections. Geriatric units seem to be reservoirs of methicillin-resistant Staphylococcus aureus (MRSA). OBJECTIVE: The first objective of this study was to determine if some characteristics identified on admission in a rehabilitation care unit could influence the colonization by the bacterium, and to define the rate of importation and acquired-infections. The second objective was to evaluate the preventive effects of enhanced cleaning with hydro-alcoholic solution, in comparison with our previous study made five years before. METHOD: One hundred and eighty-eight patients (mean age, 83.75 ± 7.35 years) were included. RESULTS: The rates of importation and colonization were respectively of 22.4% and 25.5%. The predictive factors of acquisition were dependence, malnutrition, presence of urinary catheter, and chronic wounds. The comparison with data collected five years earlier showed a reduction of colonization rates from 44 to 25%. COMMENTS: Our study highlights the important role of hand contamination in colonization of the MRSA especially for dependent patients, and shows the importance of hand-hygiene compliance, as well as maintaining autonomy among old patients. The use of hydro-alcoholic solution in association with the reinforcement of hospital hygiene measures led to the decrease of acquired-infection rate.

Auditory evoked potential patterns to voiced and voiceless speech sounds in adult developmental dyslexics with persistent deficits.

Auditory evoked potentials (AEPs) were recorded from eight developmental dyslexic adults with persistent reading, spelling and phonological deficits, and 10 non-dyslexic controls to voiced (/ba/) and voiceless (/pa/) consonant-vowel syllables. Consistent with previous data, non-dyslexics coded these stimuli differentially according to the temporal cues that form the basis of the voiced/voiceless contrast: AEPs had time-locked components with latencies that were determined by the temporal structure of the stimuli. Dyslexics were characterized by one of two electrophysiological patterns: AEP pattern I dyslexics demonstrated a differential coding of stimuli on the basis of some temporal cues, but with an atypically large number of components and a considerable delay in AEP termination time; AEP pattern II dyslexics demonstrated no clear differential coding of stimuli on the basis of temporal cues. These data reveal the presence of anomalies in cortical auditory processing which could underlie persistent perceptual and linguistic impairments in some developmental dyslexics. Furthermore, scalp AEP distribution maps showing the difference observed between /ba/ and /pa/ activity over time suggest that the regions implicated in the processing of crucial time-related acoustic cues were not systematically lateralized to the left hemisphere like they were for non-dyslexics. These findings may be conducive to a better understanding and treatment of perceptual dysfunctions in developmental language disorders.

[Resistance to linezolid in Staphylococcus aureus before its release]. / Résistance au linézolide de Staphylococcus aureus avant inscription au livret du médicament.

UNLABELLED: Resistance to antibiotics is a global problem in geriatric centres. OBJECTIVE: The aim of this study was to determine the frequency of the resistance to linezolid in Staphylococcus aureus strains before its release in a geriatric centre. METHOD: From 03-01-01 to 03-04-30 linezolid was included in the panel of antibiotics tested in S. aureus strains. The susceptibilities were estimated by the disk diffusion test in routine clinical microbiology practice. RESULTS: A total of 213 strains of S. aureus was analysed. All of them were susceptible to the following antibiotics: linezolid, cotrimoxazol, fosfomycin, and glycopeptides. The meticillin-resistant S. aureus (MRSA) represented 67.1% (60.3-73.3) strains. The resistance to pefloxacin, tobramycin and erythromycin concerned 92.3% (86.3-95.9), 73.4% (65.3-80.3) and 31.5% (24.1-39.8) of MRSA strains respectively. The MRSA strains were less resistant to the following antimicrobial drugs: gentamicin 7.0% (3.6-12.8), fusidic acid 2.1% (0.5-6.5) and rifampicin 1.4% (0.2-5.5). The resistance concerning at the same time gentamicin, pefloxacin and fucidic acid represented 2.1% (0.5-6.5) of SARM strains, rifampicin was not interested. CONCLUSION: Linezolid was effective in vitro in S. aureus strains regardless their susceptibilities in meticillin. According to its effectiveness in vivo, linezolid may be of use for the treatment of infections due to MRSA. However, there has been two reports of resistance of MRSA in clinical infections. The use of linezolid has to follow the instructions and it should be carefully monitored.