Comparison of cardiac output measured by oesophageal Doppler ultrasonography or pulse pressure contour wave analysis.

BACKGROUND: Maintaining adequate organ perfusion during high-risk surgery requires continuous monitoring of cardiac output to optimise haemodynamics. Oesophageal Doppler Cardiac Output monitoring (DCO) is commonly used in this context, but has some limitations. Recently, the cardiac output estimated by pulse pressure analysis- (PPCO) was developed. This study evaluated the agreement of cardiac output variations estimated with 9 non-commercial algorithms of PPCO compared with those obtained with DCO. METHODS: High-risk patients undergoing neurosurgery were monitored with invasive blood pressure and DCO. For each patient, 9 PPCO algorithms and DCO were recorded before and at the peak effect for every haemodynamic challenge. RESULTS: Sixty-two subjects were enrolled; 284 events were recorded, including 134 volume expansions and 150 vasopressor boluses. Among the 9 algorithms tested, the Liljestrand-Zander model led to the smallest bias (0.03 litre min(-1) [-1.31, +1.38] (0.21 litre min(-1) [-1.13; 1.54] after volume expansion and -0.13 litre min(-1) [-1.41, 1.15] after vasopressor use). The corresponding percentage of the concordance was 91% (86% after volume expansion and 94% after vasopressor use). The other algorithms, especially those using the Winkessel concept and the area under the pressure wave, were profoundly affected by the vasopressor. CONCLUSIONS: Among the 9 PPCO algorithms examined, the Liljestrand-Zander model demonstrated the least bias and best limits of agreement, especially after vasopressor use. Using this particular algorithm in association with DCO calibration could represent a valuable option for continuous cardiac output monitoring of high risk patients. CLINICAL TRIAL REGISTRATION: Comité d'éthique de la Société de Réanimation de Langue Française No. 11-356.

Sound and light from fractures in scintillators.

Prompted by intriguing events observed in certain particle-physics searches for rare events, we study light and acoustic emission simultaneously in some inorganic scintillators subject to mechanical stress. We observe mechanoluminescence in Bi4Ge3O12, CdWO4, and ZnWO4, in various mechanical configurations at room temperature and ambient pressure. We analyze the temporal and amplitude correlations between the light emission and the acoustic emission during fracture. A novel application of the precise energy calibration of Bi4Ge3O12 provided by radioactive sources allows us to deduce that the fraction of elastic energy converted to light is at least 3×10(-5).

Event-related auditory evoked potentials and amyotrophic lateral sclerosis.

OBJECTIVE: To study event-related potentials and particularly the P300 wave in a group of patients with amyotrophic lateral sclerosis (ALS), as changes in the P300 wave have been observed in many cases of brain damage-inducing cognitive impairment. DESIGN: Case series. SETTING: University hospital. PATIENTS: Twenty patients with ALS were compared with 20 healthy control subjects, with no significant age range and no significant difference in their education level. MAIN OUTCOME MEASURES: Amplitudes and latencies of long-latency auditory evoked potentials for the N100, P200, N200, and P300 waves were measured in the "odd-ball paradigm." Mental status was assessed by the Similarities subtest of the Wechsler Adult Intelligence Scale and by the Rapid Evaluation of Cognitive Function that allows for a mini-neuropsychological testing. The degree of disability was scored on the ALS Severity Scale, which rates bulbar and spinal functions. RESULTS: The latencies of the N100 and P200 waves did not appear to differ between normal and affected subjects; in contrast, the N200 and P300 latencies were significantly longer in the group with ALS. Sixty percent of the patients had a P300 latency more than 2 SDs above the theoretical norm that was established by the linear curve for control subjects. The N100, P200, N200, and P300 amplitudes showed no significant difference between the control subjects and the group of patients with ALS. There was no significant correlation between the N200 and P300 latencies and the disease duration or between the N200 and P300 latencies and the degree of motor impairment. The scores from the Rapid Evaluation of Cognitive Function were significantly lower in the group of patients with ALS than in the group of control subjects. CONCLUSIONS: A subtle cortical cognitive dysfunction is frequently observed in patients with ALS. These findings point also in the same direction as did previous neuropsychological, histological, and positron emission tomographic studies of ALS. Limb motor deficits and speech difficulties make it difficult to study the time course of changes in intellectual function in patients with ALS by using psychometric methods; thus, in the future, cognitive evoked potentials should constitute a fruitful method of testing cognitive function in patients with ALS to follow up their development over time.

[Anosognosic graphomimia: an uncommon variety of hypergraphia in right sylvian infarction]. / Graphomimie anosognosique: variété particulière d'hypergraphie au cours d'un infarctus sylvien droit.

Following a massive infarction in the territory of the right sylvian artery, a right-handed patient with a left hemiplegia and anosognosia, developed a peculiar hypergraphia. It consisted of an inappropriate and permanent writing behaviour, disappearing only during sleep. Space-constructional components of writing were severely disturbed. Graphemes were poorly formed. The graphic disturbances were different from hypergraphia previously described in stroke patients who produced linguistically correct but semantically loose writing. They were also different from graphomania reported in a case of fronto-callosal glioma. Our case of anosognosic hypergraphia suggests a sudden loss of inhibition of writing activity of the left hemisphere. The term graphomimia is proposed to distinguish this writing behaviour from the cases of hypergraphia previously reported and from graphomania.

[Cerebral infarction, cardiac myxoma and lentiginosis]. / Infarctus cérébral, myxome cardiaque et lentiginose.

Occlusion of the middle cerebral artery in a 16-year old woman revealed a left atrial myxoma associated with a mucocutaneous lentiginosis. Two-dimensional transthoracic or transesophageal echocardiography should be performed in all patients with stroke and lentiginosis to look for cardiac myxoma. After treatment of the cardiac tumor, echocardiography should be repeated at regular intervals to detect a recurrence of the myxoma. As this cardio-cutaneous syndrome is a familial disorder with autosomal dominant inheritance, examination of all family members by echocardiography is recommended.