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See detailComparison of the Surgical Pleth Index (TM) with haemodynamic variables to assess nociception-anti-nociception balance during general anaesthesia
Bonhomme, Vincent ULg; Uutela, K.; Hans, Grégory ULg et al

in British Journal of Anaesthesia (2011), 106(1), 101-11

BACKGROUND: The Surgical Pleth Index (SPI) is proposed as a means to assess the balance between noxious stimulation and the anti-nociceptive effects of anaesthesia. In this study, we compared SPI, mean ... [more ▼]

BACKGROUND: The Surgical Pleth Index (SPI) is proposed as a means to assess the balance between noxious stimulation and the anti-nociceptive effects of anaesthesia. In this study, we compared SPI, mean arterial pressure (MAP), and heart rate (HR) as a means of assessing this balance. METHODS: We studied a standard stimulus [head-holder insertion (HHI)] and varying remifentanil concentrations (CeREMI) in a group of patients undergoing neurosurgery. Patients receiving target-controlled infusions were randomly assigned to one of the three CeREMI (2, 4, or 6 ng m(1)), whereas propofol target was fixed at 3 microg ml(1). Steady state for both targets was achieved before HHI. Intravascular volume status (IVS) was evaluated using respiratory variations in arterial pressure. Prediction probability (Pk) and ordinal regression were used to assess SPI, MAP, and HR performance at indicating CeREMI, and the influence of IVS and chronic treatment for high arterial pressure, as possible confounding factors. RESULTS: The maximum SPI, MAP, or HR observed after HHI correctly indicated CeREMI in one of the two patients [accurate prediction rate (APR)=0.5]. When IVS and chronic treatment for high arterial pressure were taken into account, the APR was 0.6 for each individual variable and 0.8 when all of them predicted the same CeREMI. That increase in APR paralleled an increase in Pk from 0.63 to 0.89. CONCLUSIONS: SPI, HR, and MAP are of comparable value at gauging noxious stimulation-CeREMI balance. Their interpretation is improved by taking account of IVS, treatment for chronic high arterial pressure, and concordance between their predictions. [less ▲]

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See detailLinking sleep and general anesthesia mechanisms: this is no walkover
BONHOMME, Vincent ULg; BOVEROUX, Pierre ULg; Vanhaudenhuyse, Audrey ULg et al

in Acta Anaesthesiologica Belgica (2011), 62(3), 161-171

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See detailInfluence of anesthesia on cerebral blood flow, cerebral metabolic rate, and brain functional connectivity.
BONHOMME, Vincent ULg; BOVEROUX, Pierre ULg; HANS, Pol ULg et al

in Current Opinion in Anaesthesiology (2011), 24(5), 474-9

PURPOSE OF REVIEW: To describe recent studies exploring brain function under the influence of hypnotic anesthetic agents, and their implications on the understanding of consciousness physiology and ... [more ▼]

PURPOSE OF REVIEW: To describe recent studies exploring brain function under the influence of hypnotic anesthetic agents, and their implications on the understanding of consciousness physiology and anesthesia-induced alteration of consciousness. RECENT FINDINGS: Cerebral cortex is the primary target of the hypnotic effect of anesthetic agents, and higher-order association areas are more sensitive to this effect than lower-order processing regions. Increasing concentration of anesthetic agents progressively attenuates connectivity in the consciousness networks, while connectivity in lower-order sensory and motor networks is preserved. Alteration of thalamic sub-cortical regulation could compromise the cortical integration of information despite preserved thalamic activation by external stimuli. At concentrations producing unresponsiveness, the activity of consciousness networks becomes anticorrelated with thalamic activity, while connectivity in lower-order sensory networks persists, although with cross-modal interaction alterations. SUMMARY: Accumulating evidence suggests that hypnotic anesthetic agents disrupt large-scale cerebral connectivity. This would result in an inability of the brain to generate and integrate information, while external sensory information is still processed at a lower order of complexity. [less ▲]

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See detailUnexpected entropy response to saline spraying at the end of posterior fossa surgery: a few cases report.
Clanet, Matthieu; BONHOMME, Vincent ULg; Lhoest, L. et al

in Acta anaesthesiologica Belgica (2011), 62(2), 87-90

The Spectral Entropy proposed to monitor the depth of anesthesia includes the State Entropy (SE) computed from the EEG (0.8-32 Hz frequency band), and the Response Entropy (RE) computed from EEG and ... [more ▼]

The Spectral Entropy proposed to monitor the depth of anesthesia includes the State Entropy (SE) computed from the EEG (0.8-32 Hz frequency band), and the Response Entropy (RE) computed from EEG and facial muscles activity (0.5-47 Hz frequency band). We report an unexpected Entropy response to saline spraying at the end of posterior fossa surgery. Six patients undergoing scheduled functional surgery of the posterior fossa were included in this report. They were anesthetized with propofol and remifentanil using TCI and received an intubation dose of rocuronium. At the end of surgery, saline spraying, performed for hemostatic purpose and wreckage elimination, resulted in a sustained increase in RE and SE without hemodynamic modification in four patients, while no change was observed in the two other ones. In one of the responding patients, 0.1 mg kg(-1) rocuronium attenuated the Entropy response. In the two non responders, repetition of spraying or rocuronium administration did not change Entropy value. Recovery from anesthesia was comparable in all patients and none of them complained from awareness. We conclude that Entropy can increase during posterior fossa surgery in non-paralyzed patients. This response probably reflects an increase in facial muscle activity rather than a change in depth of anesthesia, as far as it can be attenuated by a small dose of rocuronium. While this hypothesis requires further investigation, these observations suggest that saline spraying may confound interpretation of Entropy during posterior fossa surgery. [less ▲]

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See detailIntravenous lidocaine infusion reduces bispectral index-guided requirements of propofol only during surgical stimulation.
Hans, Grégory ULg; Lauwick, Séverine ULg; Kaba, Abdourahmane ULg et al

in British Journal of Anaesthesia (2010), 105(4), 471-9

BACKGROUND: I.V. lidocaine reduces volatile anaesthetics requirements during surgery. We hypothesized that lidocaine would also reduce propofol requirements during i.v. anaesthesia. METHODS: A randomized ... [more ▼]

BACKGROUND: I.V. lidocaine reduces volatile anaesthetics requirements during surgery. We hypothesized that lidocaine would also reduce propofol requirements during i.v. anaesthesia. METHODS: A randomized controlled study of 40 patients tested the effect of i.v. lidocaine (1.5 mg kg(-1) then 2 mg kg(-1) h(-1)) on propofol requirements. Anaesthesia was maintained with remifentanil and propofol target-controlled infusions (TCI) to keep the bispectral index (BIS) around 50. Effect-site concentrations of propofol and remifentanil and BIS values were recorded before and after skin incision. Data were analysed using anova and mixed effects analysis with NONMEM. Two dose-response studies were then performed with and without surgical stimulation. Propofol TCI titrated to obtain a BIS around 50 was kept constant. Then patients were randomized into four groups: A, saline; B, 0.75 mg kg(-1) bolus then infusion 1 mg kg(-1) h(-1); C, 1.5 mg kg(-1) bolus and infusion 2 mg kg(-1) h(-1); and D, 3 mg kg(-1) bolus and infusion 4 mg kg(-1) h(-1). Lidocaine administration coincided with skin incision. BIS values and haemodynamic variables were recorded. Data were analysed using linear regression and two-way anova. RESULTS: Lidocaine decreased propofol requirements (P<0.05) only during surgery. In the absence of surgical stimulation, lidocaine did not affect BIS nor haemodynamic variables, whereas it reduced BIS increase (P=0.036) and haemodynamic response (P=0.006) secondary to surgery. CONCLUSIONS: The sparing effect of lidocaine on anaesthetic requirements seems to be mediated by an anti-nociceptive action. [less ▲]

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See detailSide effects of the addition of clonidine 75 microg or sufentanil 5 microg to 0.2% ropivacaine for labour epidural analgesia.
Dewandre, Pierre-Yves ULg; Decurninge, Valérie; Bonhomme, Vincent ULg 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 ▲]

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See detailEffect of an intravenous infusion of lidocaine on cisatracurium-induced neuromuscular block duration: a randomized-controlled trial.
Hans, Grégory ULg; Defresne, Aline ULg; Ki, Bertille 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 ▲]

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See detailLes thrombopénies induites par l'héparine (TIH)
Baccus, Christine ULg; Hans, Pol ULg; Brichant, Jean-François ULg

in Revue Médicale de Liège (2009), 64(9), 450-456

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See detailManagement of the unstable cervical spine: elective versus emergent cases.
Bonhomme, Vincent ULg; Hans, Pol ULg

in Current Opinion in Anaesthesiology (2009), 22(5), 579-85

PURPOSE OF REVIEW: The present review focuses on similarities and discrepancies in the management of emergent and elective unstable cervical spine (C-spine) patients. RECENT FINDINGS: During mobilization ... [more ▼]

PURPOSE OF REVIEW: The present review focuses on similarities and discrepancies in the management of emergent and elective unstable cervical spine (C-spine) patients. RECENT FINDINGS: During mobilization, lifting is superior to rolling in limiting spine movements. Before prone position surgery, the transfer of the patient on a rotating table is preferable to rolling. In trauma patients, helical computed tomography (CT) with sagittal reconstruction is the first choice for clearing the C-spine. In those patients, airway compromise may be related to hidden cervical edema or hematoma. Several devices can be of help in performing safe tracheal intubation in patients with limited neck movements, but awake fiberoptic intubation remains the safest procedure. The muscle relaxant antagonist sugammadex can improve safety for rapid sequence induction. It can rapidly reverse profound steroid-based neuromuscular blockade and allows avoidance of succinylcholine in this indication. Propofol anesthesia better prevents coughing upon emergence than inhaled anesthesia. Neuroprotection in cord-damaged patients is disappointing, and the controversy on the efficacy of high-dose methylprednisolone is not closed. Nevertheless, maintenance of homeostasis remains the cornerstone of neuroprotection. SUMMARY: Subtle details differentiate the management of emergent and elective unstable C-spine patients. In both situations, the presence or the absence of a neurological insult governs the therapeutic strategy. [less ▲]

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See detailPerioperative management of a child with von Willebrand disease undergoing surgical repair of craniosynostosis: looking at unusual targets.
Maquoi, Isabelle ULg; Bonhomme, Vincent ULg; Born, Jacques Daniel et al

in Anesthesia and Analgesia (2009), 109(3), 720-4

We report the successful management of a craniosynostosis repair in a child with severe Type I von Willebrand disease diagnosed during the preoperative assessment and treated by coagulation factor VIII ... [more ▼]

We report the successful management of a craniosynostosis repair in a child with severe Type I von Willebrand disease diagnosed during the preoperative assessment and treated by coagulation factor VIII and ristocetin cofactor. Collaboration among the anesthesiologist, the neurosurgeon, the clinical pathologist, and the pediatric hematologist is important for successful management. [less ▲]

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See detailAcid-base status and hemodynamic stability during propofol and sevoflurane-based anesthesia in patients undergoing uncomplicated intracranial surgery.
Bonhomme, Vincent ULg; Demoitie, Jeannick ULg; Schaub, Isabelle ULg et al

in Journal of Neurosurgical Anesthesiology (2009), 21(2), 112-9

Propofol anesthesia may induce metabolic disturbances and sevoflurane anesthesia arterial hypotension. This study compares both techniques regarding acid-base and hemodynamic status during intracranial ... [more ▼]

Propofol anesthesia may induce metabolic disturbances and sevoflurane anesthesia arterial hypotension. This study compares both techniques regarding acid-base and hemodynamic status during intracranial surgery. Sixty-one patients were randomized into 2 groups according to anesthesia maintenance, a propofol group (n=30), and a sevoflurane group (n=31). The anesthesia protocol including rocuronium and remifentanil infusion was otherwise similar in both groups. Arterial blood samples were drawn every 2 hours during the procedure and upon arrival in the intensive care unit to assess acid-base status. The number of hypotensive and hypertensive events served to assess hemodynamic stability. Metabolic acidosis was more frequent during propofol than sevoflurane anesthesia (7 out of 29 and 1 out of 31, P=0.02). Its severity was linearly correlated with lactate concentration (R=0.32), total dose of propofol (R=0.2), and length of procedure (R=0.28). Hyperlactacidemia was also observed during sevoflurane anesthesia, but without acidosis. Hypertension occurred more frequently during propofol than sevoflurane anesthesia (13 out of 30 vs. 1 out of 31, P<0.001), particularly in patients with a past medical history of hypertension. Higher remifentanil infusion rates reduced the risk of hypertension. Conversely, sevoflurane anesthesia favored arterial hypotension (22 out of 31 vs. 12 out of 30, P=0.015). Preoperative morning administration of antihypertensive medications to patients with a history of arterial hypertension was associated with a low probability of hypertensive events, at the cost of more frequent hypotension. In conclusion, propofol anesthesia for intracranial surgery is more frequently associated with lactic acidosis and hypertension; sevoflurane anesthesia may favor arterial hypotension. [less ▲]

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See detailAwake craniotomy
Bonhomme, Vincent ULg; Franssen, Colette ULg; Hans, Pol ULg

in European Journal of Anaesthesiology (2009), 26(11), 906-912

Awake craniotomy has become an increasingly frequent procedure. In this paper, the principles of its anaesthetic management are reviewed. The means allowing achievement of anaesthetic objectives are ... [more ▼]

Awake craniotomy has become an increasingly frequent procedure. In this paper, the principles of its anaesthetic management are reviewed. The means allowing achievement of anaesthetic objectives are described, with emphasis on points that determine success of the procedure. A careful and adequate selection and preparation of patients are mandatory, and the intervening team must be a skilled team. Choosing an awake technique or general anaesthesia depends on several factors, including the risk of obstructive apnoea, seizures, nausea and vomiting, patient's ability to cooperate, and localization of lesions. The main challenge of intraoperative anaesthetic management relies on the ability of rapidly adjusting the level of sedation and analgesia according to the sequence of surgical events, while ensuring haemodynamic stability, adequate ventilation, and minimal interference with eventual eletrophysiological recordings. Throughout the procedure, complications must be anticipated and managed according to predefined guidelines. More prospective randomized clinical trials are still needed to improve safety and efficacy of awake craniotomies, as well as to validate this technique in comparison with more conventional anaesthetic management. [less ▲]

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See detailThe Effect of Clonidine Infusion on Distribution of Regional Cerebral Blood Flow in Volunteers
Bonhomme, Vincent ULg; Maquet, Pierre ULg; Phillips, Christophe ULg et al

in Anesthesia and Analgesia (2008), 106(3), 899-909

BACKGROUND: Through their action on the locus coeruleus, alpha2-adrenoceptor agonists induce rapidly reversible sedation while partially preserving cognitive brain functions. Our goal in this ... [more ▼]

BACKGROUND: Through their action on the locus coeruleus, alpha2-adrenoceptor agonists induce rapidly reversible sedation while partially preserving cognitive brain functions. Our goal in this observational study was to map brain regions whose activity is modified by clonidine infusion so as to better understand its loci of action, especially in relation to sedation. METHODS: Six ASA I-II right-handed volunteers were recruited. Electroencephalogram (EEG) was monitored continuously. After a baseline H2(15)O activation scan, clonidine infusion was started at a rate ranging from 6 to 10 microg x kg(-1) x h(-1). A sequence of 11 similar scans was then performed at 8 min intervals. Plasma clonidine concentration was measured. Using statistical parametric mapping, we sought linear correlations between normalized regional cerebral blood flow (rCBF), an indicator of regional brain activity, and plasma clonidine concentration or spindle EEG activity. RESULTS: Clonidine induced clinical sedation and EEG patterns (spindles) comparable to early stage nonrapid eye movement sleep. A significant negative linear correlation between clonidine concentration and rCBF or spindle activity was observed in the thalamus, prefrontal, orbital and parietal association cortex, posterior cingulate cortex, and precuneus. CONCLUSIONS: The EEG patterns and decreases in rCBF of specific brain regions observed during clonidine-induced sedation are similar to those of early stage nonrapid eye movement sleep. Patterns of deactivated brain regions are also comparable to those observed during general anesthesia or vegetative state, reinforcing the hypothesis that alterations in the activity of a common network occur during these modified conscious states. [less ▲]

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See detailDelta down compared with delta pulse as an indicator of volaemia during intracranial surgery
Deflandre, Eric; Bonhomme, Vincent ULg; Hans, Pol ULg

in British Journal of Anaesthesia (2008), 100(2), 245-250

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See detailIncreased analgesic requirements associated with induced labour are related to dystocia
Sougné, Christelle; Dewandre, Pierre-Yves ULg; Hans, Pol ULg et al

in Acta Anaesthesiologica Belgica (2008), 59(3), 229

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