Default network connectivity reflects the level of consciousness in non-communicative brain-damaged patients.
Vanhaudenhuyse, Audrey ; Noirhomme, Quentin ; Tshibanda, Luaba et al
in Brain : A Journal of Neurology (2010), 133(Pt 1), 161-71
The 'default network' is defined as a set of areas, encompassing posterior-cingulate/precuneus, anterior cingulate/mesiofrontal cortex and temporo-parietal junctions, that show more activity at rest than ... [more ▼]
The 'default network' is defined as a set of areas, encompassing posterior-cingulate/precuneus, anterior cingulate/mesiofrontal cortex and temporo-parietal junctions, that show more activity at rest than during attention-demanding tasks. Recent studies have shown that it is possible to reliably identify this network in the absence of any task, by resting state functional magnetic resonance imaging connectivity analyses in healthy volunteers. However, the functional significance of these spontaneous brain activity fluctuations remains unclear. The aim of this study was to test if the integrity of this resting-state connectivity pattern in the default network would differ in different pathological alterations of consciousness. Fourteen non-communicative brain-damaged patients and 14 healthy controls participated in the study. Connectivity was investigated using probabilistic independent component analysis, and an automated template-matching component selection approach. Connectivity in all default network areas was found to be negatively correlated with the degree of clinical consciousness impairment, ranging from healthy controls and locked-in syndrome to minimally conscious, vegetative then coma patients. Furthermore, precuneus connectivity was found to be significantly stronger in minimally conscious patients as compared with unconscious patients. Locked-in syndrome patient's default network connectivity was not significantly different from controls. Our results show that default network connectivity is decreased in severely brain-damaged patients, in proportion to their degree of consciousness impairment. Future prospective studies in a larger patient population are needed in order to evaluate the prognostic value of the presented methodology. [less ▲]Detailed reference viewed: 95 (22 ULg)
Sevrage tabagique en préopératoire: une période propice pour lutter contre l'inertie et le défaut d'observance
; ; Clerdain, Anne-Michèle et al
in Revue Médicale de Liège (2010), 65(5-6), 332-337Detailed reference viewed: 29 (5 ULg)
Faut-il prescrire systématiquement un bilan d'hémostase avant la réalisation d'une péridurale analgésique pour le travail en obstétrique?
; Dewandre, Pierre-Yves ; Brichant, Jean-François
in Revue Médicale de Liège (2010), 65(1), 35-39Detailed reference viewed: 56 (8 ULg)
Breakdown of within- and between-network resting state functional magnetic resonance imaging connectivity during propofol-induced loss of consciousness.
Boveroux, Pierre ; Vanhaudenhuyse, Audrey ; Bruno, Marie-Aurélie et al
in Anesthesiology (2010), 113(5), 1038-53
BACKGROUND: Mechanisms of anesthesia-induced loss of consciousness remain poorly understood. Resting-state functional magnetic resonance imaging allows investigating whole-brain connectivity changes ... [more ▼]
BACKGROUND: Mechanisms of anesthesia-induced loss of consciousness remain poorly understood. Resting-state functional magnetic resonance imaging allows investigating whole-brain connectivity changes during pharmacological modulation of the level of consciousness. METHODS: Low-frequency spontaneous blood oxygen level-dependent fluctuations were measured in 19 healthy volunteers during wakefulness, mild sedation, deep sedation with clinical unconsciousness, and subsequent recovery of consciousness. RESULTS: Propofol-induced decrease in consciousness linearly correlates with decreased corticocortical and thalamocortical connectivity in frontoparietal networks (i.e., default- and executive-control networks). Furthermore, during propofol-induced unconsciousness, a negative correlation was identified between thalamic and cortical activity in these networks. Finally, negative correlations between default network and lateral frontoparietal cortices activity, present during wakefulness, decreased proportionally to propofol-induced loss of consciousness. In contrast, connectivity was globally preserved in low-level sensory cortices, (i.e., in auditory and visual networks across sedation stages). This was paired with preserved thalamocortical connectivity in these networks. Rather, waning of consciousness was associated with a loss of cross-modal interactions between visual and auditory networks. CONCLUSIONS: Our results shed light on the functional significance of spontaneous brain activity fluctuations observed in functional magnetic resonance imaging. They suggest that propofol-induced unconsciousness could be linked to a breakdown of cerebral temporal architecture that modifies both within- and between-network connectivity and thus prevents communication between low-level sensory and higher-order frontoparietal cortices, thought to be necessary for perception of external stimuli. They emphasize the importance of thalamocortical connectivity in higher-order cognitive brain networks in the genesis of conscious perception. [less ▲]Detailed reference viewed: 192 (12 ULg)
Side effects of the addition of clonidine 75 microg or sufentanil 5 microg to 0.2% ropivacaine for labour epidural analgesia.
Dewandre, Pierre-Yves ; ; Bonhomme, Vincent et al
in International Journal of Obstetric Anesthesia (2010), 19(2), 149-54
BACKGROUND: Sufentanil 5 microg and clonidine 75 microg produce a similar reduction in minimum local anaesthetic concentration of ropivacaine. The aim of the present study was to compare the side effects ... [more ▼]
BACKGROUND: Sufentanil 5 microg and clonidine 75 microg produce a similar reduction in minimum local anaesthetic concentration of ropivacaine. The aim of the present study was to compare the side effects of two equianalgesic solutions by combining 0.2% ropivacaine with either sufentanil 5 microg or clonidine 75 microg for labour epidural analgesia. METHODS: In a prospective double-blind study, 60 women at 5 cm cervical dilatation were randomly allocated to receive 0.2% ropivacaine with either sufentanil 5 microg or clonidine 75 microg to initiate labour analgesia. The analgesic efficacy and side effects of the two mixtures were compared. RESULTS: Onset, duration and quality of analgesia and subsequent ropivacaine consumption were similar in the two groups. Hypotension was significantly more frequent and severe with clonidine than with sufentanil (systolic blood pressure <100 mmHg: 17/26 vs. 6/24, P <0.05; systolic blood pressure <90 mmHg: 5/26 vs. 0/24, P <0.05) resulting in more frequent ephedrine administration (11/26 vs. 2/24, P <0.05) and larger fluid requirements (1696 +/- 583 mL vs. 1264 +/- 407 mL, P < 0.05). Conversely, pruritus was more frequent with sufentanil than with clonidine (6/26 vs. 1/24, P <0.05). CONCLUSIONS: Hypotension occurs more frequently when clonidine is added to epidural ropivacaine instead of an equianalgesic dose of sufentanil. Therefore, clonidine cannot be recommended for routine administration for labour epidural analgesia. [less ▲]Detailed reference viewed: 64 (0 ULg)
Anesthésie locorégionale et anti-agrégants plaquettaires: le jeu en vaut-il la chandelle?
Senard, Marc ; Roediger, Laurence ; Hubert, Marie-Bernard et al
in Praticien en Anesthésie Réanimation (Le) (2010), 14Detailed reference viewed: 60 (12 ULg)
Management of severe preeclampsia
Brichant, Géraldine ; Dewandre, Pierre-Yves ; Foidart, Jean-Michel et al
in Acta Clinica Belgica (2010), 65(3), 163-169
Features of severe preeclampsia include severe proteinuric hypertension and symptoms of central nervous system dysfunction, hepatocellular injury, thrombocytopenia, oliguria, pulmonary oedema ... [more ▼]
Features of severe preeclampsia include severe proteinuric hypertension and symptoms of central nervous system dysfunction, hepatocellular injury, thrombocytopenia, oliguria, pulmonary oedema, cerebrovascular accident and severe intrauterine growth restriction. Women with severe preeclampsia must be hospitalized to confirm the diagnosis, to assess the severity of the disease, to monitor the progression of the disease and to try to stabilize the disease. Severe preeclampsia may be managed expectantly, in selected cases. The objective of expectant management in these patients is to improve neonatal outcome. Expectant management is based on antihypertensive treatment and prevention of end organ dysfunction. Antihypertensive treatment improves maternal outcome but has the potential to be deleterious for the foetus. Plasma volume expansion has been suggested for severe preeclampsia but trials failed to show any benefit. Magnesium sulfate is the anticonvulsivant of choice to treat or prevent eclampsia when indicated. Antenatal corticosteroids are recommended in severely preeclamptic women with 26-34 weeks gestation. Timing of delivery is based upon gestational age, severity of preeclampsia, maternal and foetal risks. [less ▲]Detailed reference viewed: 98 (21 ULg)
Manifestations hemodynamiques et respiratoires de la preeclampsie.
Brichant, Jean-François ; Brichant, Géraldine ; Dewandre, Pierre-Yves et al
in Annales Françaises d'Anesthésie et de Réanimation (2010), 29
The hemodynamic and cardiovascular changes seen during PE vary according to the natural history of the disease, its severity and eventual therapeutic measures taken. In the early stages of pregnancy ... [more ▼]
The hemodynamic and cardiovascular changes seen during PE vary according to the natural history of the disease, its severity and eventual therapeutic measures taken. In the early stages of pregnancy, patients who will eventually develop PE, present with a blood pressure which even though within normal limits, is higher than in other women. Similarly, their cardiac output is higher with a normal or decreased peripheral vascular resistance. As soon as the clinical signs of the disease appear, the hemodynamic picture usually shifts toward that of a high peripheral resistance with low cardiac output. Sometimes however, a clinically hyperkinetic circulation may be demonstrated. In PE patients, cardiac preload pressures are usually normal even though the circulatory volumes are lower by 600 to 800ml when compared to those found in normal pregnancy. The cardiac function is however usually preserved during PE. PE induces an exaggerated capillary permeability. This results in the worsening of the airway edema which may render the intubation very difficult. The increased capillary permeability contributes, among other factors, to the heightened risk of acute pulmonary edema. It is not justified to administer an anti-hypertensive treatment to PE women presenting with only moderate hypertension. An anti-hypertensive treatment must only be initiated whenever the hypertension is severe (i.e. SBP>/=160mmHg and/or DBP>/=110mmHg) in order to reduce the risk of maternal complications. In the absence of objective comparative data assessing anti-hypertensive agents for the PE patient, the choice of therapy relies predominantly on the practitioners' own experience. Systematic circulatory volume expansion has not been proven to improve the maternal nor the neonatal prognosis. Such treatment is to be reserved solely for situations in which correcting a hypo-volemia is absolutely necessary. The treatment of acute pulmonary edema in a PE patient is symptomatic and includes the administration of vasodilating agents and of diuretics. A benefit in setting-up an invasive monitoring of the pulmonary artery occlusive pressure has not been demonstrated. The sonographic surveillance of the hemodynamic state can however be useful in these circumstances. [less ▲]Detailed reference viewed: 46 (7 ULg)
Effect of an intravenous infusion of lidocaine on cisatracurium-induced neuromuscular block duration: a randomized-controlled trial.
Hans, Grégory ; Defresne, Aline ; et al
in Acta Anaesthesiologica Scandinavica (2010), 54(10), 1192-6
BACKGROUND: Intravenous lidocaine can be used intraoperatively for its analgesic and antihyperalgesic properties but local anaesthetics may also prolong the duration of action of neuromuscular blocking ... [more ▼]
BACKGROUND: Intravenous lidocaine can be used intraoperatively for its analgesic and antihyperalgesic properties but local anaesthetics may also prolong the duration of action of neuromuscular blocking agents. We hypothesized that intravenous lidocaine would prolong the time to recovery of neuromuscular function after cisatracurium. METHODS: Forty-two patients were enrolled in this randomized, double-blind, placebo-controlled study. Before induction, patients were administered either a 1.5 mg/kg bolus of intravenous lidocaine followed by a 2 mg/kg/h infusion or an equal volume of saline. Anaesthesia was induced and maintained using propofol and remifentanil infusions. After loss of consciousness, a 0.15 mg/kg bolus of cisatracurium was administered. No additional cisatracurium injection was allowed. Neuromuscular function was assessed every 20 s using kinemyography. The primary endpoint was the time to spontaneous recovery of a train-of-four (TOF) ratio >/= 0.9. RESULTS: The time to spontaneous recovery of a TOF ratio >/= 0.9 was 94 +/- 15 min in the control group and 98 +/- 16 min in the lidocaine group (P=0.27). CONCLUSIONS: No significant prolongation of spontaneous recovery of a TOF ratio >/= 0.9 after cisatracurium was found in patients receiving intravenous lidocaine. [less ▲]Detailed reference viewed: 59 (3 ULg)
Neurokinin-1 receptor antagonists in the prevention of postoperative nausea and vomiting
; ; Brichant, Jean-François
in British Journal of Anaesthesia (2009), 103(1), 7-13Detailed reference viewed: 10 (1 ULg)
Traitement de la prééclampsie sévère: jusqu'où, et pour quels risques/bénéfices?
PETIT, Philippe ; ; CHANTRAINE, Frédéric et al
in Revue Médicale de Liège (2009), 64(12), 620-625Detailed reference viewed: 123 (11 ULg)
Pain and non-pain processing during hypnosis: a thulium-YAG event-related fMRI study.
Vanhaudenhuyse, Audrey ; Boly, Mélanie ; Balteau, Evelyne et al
in NeuroImage (2009), 47(3), 1047-54
The neural mechanisms underlying the antinociceptive effects of hypnosis still remain unclear. Using a parametric single-trial thulium-YAG laser fMRI paradigm, we assessed changes in brain activation and ... [more ▼]
The neural mechanisms underlying the antinociceptive effects of hypnosis still remain unclear. Using a parametric single-trial thulium-YAG laser fMRI paradigm, we assessed changes in brain activation and connectivity related to the hypnotic state as compared to normal wakefulness in 13 healthy volunteers. Behaviorally, a difference in subjective ratings was found between normal wakefulness and hypnotic state for both non-painful and painful intensity-matched stimuli applied to the left hand. In normal wakefulness, non-painful range stimuli activated brainstem, contralateral primary somatosensory (S1) and bilateral insular cortices. Painful stimuli activated additional areas encompassing thalamus, bilateral striatum, anterior cingulate (ACC), premotor and dorsolateral prefrontal cortices. In hypnosis, intensity-matched stimuli in both the non-painful and painful range failed to elicit any cerebral activation. The interaction analysis identified that contralateral thalamus, bilateral striatum and ACC activated more in normal wakefulness compared to hypnosis during painful versus non-painful stimulation. Finally, we demonstrated hypnosis-related increases in functional connectivity between S1 and distant anterior insular and prefrontal cortices, possibly reflecting top-down modulation. [less ▲]Detailed reference viewed: 131 (29 ULg)
Analgésie après chirurgie orthopédique du membre inférieur: intérêt de l'anesthésie locorégionale périphérique
Godfroid, Nathalie ; Lecoq, Jean-Pierre ; Remy, Bernadette et al
in Revue Médicale de Liège (2009), 64(12), 639-644Detailed reference viewed: 114 (13 ULg)
Mécanismes de l'anesthésie générale: apport de l'imagerie fonctionnelle
Boveroux, Pierre ; Bonhomme, Vincent ; Kirsch, Murielle et al
in Revue Médicale de Liège (2009), 64(Synthèse 2009), 36-41Detailed reference viewed: 110 (22 ULg)
Manifestations hémodynamiques et respiratoires de la prééclampsie
Brichant, Jean-François ; Brichant, Géraldine ; Dewandre, Pierre-Yves et al
in Pottecher, Thierry; Luton, Dominique (Eds.) Prise en charge multidisciplinaire de la prééclampsie (2009)Detailed reference viewed: 39 (7 ULg)
Pulmonary embolism in a trauma patient with liver and orthopedic injuries
Legrain, Caroline ; Hans, Grégory ; Defresne, Aline et al
in Acta Anaesthesiologica Belgica (2009), 60(4), 259-262Detailed reference viewed: 88 (3 ULg)
Prise en charge multidisciplinaire de la prééclampsie. Recommandations formalisées d'experts communes
Brichant, Jean-François ; ; et al
in Annales Françaises d'Anesthésie et de Réanimation (2009), 28(3), 275-281Detailed reference viewed: 91 (13 ULg)
Postoperative respiratory problems in morbidly obese patients.
Hans, Grégory ; Lauwick, Séverine ; Kaba, Abdourahmane et al
in Acta Anaesthesiologica Belgica (2009), 60(3), 169-75
Morbid obesity results in a restrictive pulmonary syndrome including decreased functional residual capacity. General anaesthesia further decreases functional residual capacity, and consequently alters gas ... [more ▼]
Morbid obesity results in a restrictive pulmonary syndrome including decreased functional residual capacity. General anaesthesia further decreases functional residual capacity, and consequently alters gas exchanges more profoundly in morbidly obese patients than in nonobese patients. Moreover, these changes persist longer during the postoperative period, rendering obese subjects vulnerable to postoperative respiratory complications. In this review, we present postoperative measures improving respiratory function of these patients. Whether these measures affect outcome remains however unknown. Patients suffering from obstructive sleep apnoea syndrome deserve special considerations that are briefly described. Finally, the algorithm of the postoperative respiratory management of morbid obese patients used in our institution is provided. [less ▲]Detailed reference viewed: 70 (3 ULg)