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Jean-Philippe Derenne

Publications and source records attributed to Jean-Philippe Derenne.

At least 19 recordsLinked to original sources
PubMed2006

Inspiratory resistances facilitate the diaphragm response to transcranial stimulation in humans.

BACKGROUND: Breathing in humans is dually controlled for metabolic (brainstem commands) and behavioral purposes (suprapontine commands) with reciprocal modulation through spinal integration. Whereas the ventilatory response to chemical stimuli arises from the brainstem, the compensation of mechanical loads in awake humans is thought to involve suprapontine mechanisms. The aim of this study was to test this hypothesis by examining the effects of inspiratory resistive loading on the response of the diaphragm to transcranial magnetic stimulation. RESULTS: Six healthy volunteers breathed room air without load (R0) and then against inspiratory resistances (5 and 20 cmH2O/L/s, R5 and R20). Ventilatory variables were recorded. Transcranial magnetic stimulation (TMS) was performed during early inspiration (I) or late expiration (E), giving rise to motor evoked potentials (MEPs) in the diaphragm (Di) and abductor pollicis brevis (APB). Breathing frequency significantly decreased during R20 without any other change. Resistive breathing had no effect on the amplitude of Di MEPs, but shortened their latency (R20: -0.903 ms, p = 0.03) when TMS was superimposed on inspiration. There was no change in APB MEPs. CONCLUSION: Inspiratory resistive breathing facilitates the diaphragm response to TMS while it does not increase the automatic drive to breathe. We interpret these findings as a neurophysiological substratum of the suprapontine nature of inspiratory load compensation in awake humans.

Airway Resistance↗
PubMed2006

Dyspnea as a noxious sensation: inspiratory threshold loading may trigger diffuse noxious inhibitory controls in humans.

Dyspnea, a leading respiratory symptom, shares many clinical, physiological, and psychological features with pain. Both activate similar brain areas. The neural mechanisms of dyspnea are less well described than those of pain. The present research tested the hypothesis of common pathways between the two sensations. Six healthy men (age 30-40 yr) were studied. The spinal nociceptive flexion reflex (RIII) was first established in response to electrical sural stimulation. Dyspnea was then induced through inspiratory threshold loading, forcing the subjects to develop 70% of their maximal inspiratory pressure to inhale. This led to progressive inhibition of the RIII reflex that reached 50 +/- 12% during the fifth minute of loading (P < 0.001), was correlated to the intensity of the self-evaluated respiratory discomfort, and had recovered 5 min after removal of the load. The myotatic H-reflex was not inhibited by inspiratory loading, arguing against postsynaptic alpha motoneuron inhibition. Dyspnea, like pain, thus induced counterirritation, possibly indicating a C-fiber stimulation and activation of diffuse noxious inhibitory descending controls known to project onto spinal dorsal horn wide dynamic range neurons. This confirms the noxious nature of certain types of breathlessness, thus opening new physiological and perhaps therapeutic perspectives.

Adult↗
PubMed2006

Responses of the diaphragm to transcranial magnetic stimulation during wake and sleep in humans.

UNLABELLED: The human ventilation depends on bulbospinal and corticospinal commands. This study assessed their interactions in five healthy volunteers (two men, age 25-35) through the description of diaphragm and abductor pollicis brevis (APB) motor potentials (DiMEPs, abpMEPs) evoked by transcranial magnetic stimulation (TMS) during relaxed expiration and tidal inspiration and during wake and sleep. NREM decreased corticospinal excitability and REM further did so, for both the diaphragm and the APB. During wake, inspiration shortened supine DiMEPs latencies (expiration 18.56+/-1.90ms; inspiration 17.37+/-1.48ms, P<0.001). This persisted during sleep in an augmented manner (expiration: 21.05+/-1.39ms; inspiration 18.69+/-1.17ms, P=0.002). Inspiration had no effect on apbMEPs during wake and sleep. IN CONCLUSION: (1) the tidal bulbospinal input to phrenic motoneurones is sufficient to modulate the throughput of the corticospinal pathway to these neurones; (2) this modulation is best seen after the sleep related removal of corticospinal and/or afferent inputs.

Adult↗
PubMed2006

Reduced breathing variability as a predictor of unsuccessful patient separation from mechanical ventilation.

OBJECTIVES: To compare descriptors of the breath-to-breath respiratory variability during a 60-min spontaneous breathing trial in patients successfully and unsuccessfully separated from the ventilator and the endotracheal tube and to assess the usefulness of these predictors in discriminating these two categories of patients. DESIGN: Prospective observational study. SETTING: Four general intensive care units in university hospitals. PATIENTS: A total of 51 consecutive patients mechanically ventilated for >24 hrs. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Tidal volume, respiratory period, inspiratory time, expiratory time, mean inspiratory flow (tidal volume/inspiratory time), and duty cycle (inspiratory time/respiratory period) were obtained from the flow signal. Breath-by-breath variability was expressed in terms of their coefficients of variation (CV), the number of breaths among which a significant correlation was found (lag), and the autocorrelation coefficient between one breath and the following one. Five patients were excluded because of nonstationarity of the data, leaving 46 cases for analysis. Between-group comparison was conducted with the Mann-Whitney test, and a nonparametric classification and regression tree was used to identify variables discriminating "success" (n = 32) and "failure" patients (n = 14). All coefficients of variation were significantly higher in success patients, who also exhibited significantly less respiratory autocorrelation (shorter "short memory"). The classification and regression tree analysis allocated all success patients to a group defined by a coefficient of variation of tidal volume/inspiratory time of > or =19% and a coefficient of variation of inspiratory time/respiratory period of > or =10% that did not contain any failure patient. All failure patients belonged to a group with coefficient of variation of tidal volume/inspiratory time of <19%, a lag tidal volume of > or =11, and that contained no success patient. CONCLUSIONS: In intensive care unit patients undergoing a spontaneous breathing trial, breathing variability is greater in patients successfully separated from the ventilator and the endotracheal tube. Variability indices are sufficient to separate success from failure cases.

Acidosis, Respiratory↗
PubMed2005

Stages 1-2 non-rapid eye movement sleep behavior disorder associated with dementia: a new parasomnia?

A 55-year-old woman with a progressive dementia and frontal syndrome was hospitalized because she was agitated every night after falling asleep (spoke, laughed, cried, tapped, kicked, walked, and fell down). She slept 5.5 hours during video polysomnography, but the theta rhythm electroencephalograph recording typical of sleep stages 1 to 2 and the spindles and K-complexes typical of sleep stage 2 contrasted with continuous muscular twitching, prominent rapid eye movements, vocalizations, and continuous, complex, purposeful movements typical of rapid eye movement (REM) sleep behavior disorder. This newly described stages 1--2 non-REM sleep behavior disorder suggests that central motor pattern generators were disinhibited during non-REM sleep.

Dementia↗
PubMed2005

Diaphragmatic dysfunction in patients with idiopathic inflammatory myopathies.

Polymyositis, dermatopolymyositis, and inclusion body myositis imply chronic inflammation of skeletal muscles. Pulmonary complications include aspiration pneumonia, interstitial pneumonitis, or respiratory muscle myositis. This study aims at better describing their impact on respiratory muscle. Twenty-three consecutive patients (12 PM, 5 DM, 6 IBM) were studied (static inspiratory and expiratory pressures; diaphragm function in terms of the mouth and transdiaphragmatic pressure responses to bilateral phrenic stimulation). Pulmonary parenchymatous abnormalities were mild (6 cases) or absent. The mouth pressure produced by phrenic stimulation was 6.83+/-3.01 cm H2O, with 18 patients (78%) diagnosed with diaphragm weakness (<10 cm H2O) and lower values in DM (4.35+/-1.48 cm H2O) than in IBM and in PM (P<0.05). Diaphragm weakness is frequent and probably overlooked in inflammatory myopathies. Further studies are needed to delineate the clinical relevance of these results.

Aged↗
PubMed2005

Patients aged 90 years or older in the intensive care unit.

BACKGROUND: Age is an important prognostic factor in patients admitted to intensive care units (ICUs), but it is not as important as illness severity. However, age seems to remain an important independent triage criterion for ICU admission, and 90 years of age seems to represent a psychological barrier for many ICU physicians. The aim of this preliminary study is to compare the management and outcome of patients aged 90 years or older admitted to a respiratory ICU with those of patients aged 70 years or younger. METHODS: In our matched case-control study over a 6-year period, 36 patients aged 90 years or older (case patients) were selected and matched according to sex with 72 controls chosen in the 20- to 69-year age range. The Simplified Acute Physiology Score (SAPS) II was then computed without using age as a variable. RESULTS: Pre-existing comorbidities were significantly less frequent in cases than in controls (5.1% vs 30.5%, p <.01). Compared to controls, cases were more frequently admitted for cardiac failure (22% vs 7%, p <.05) and less frequently for neurological diseases (0% vs 11%, p <.05). The use of advanced life-support measures in the ICU such as mechanical ventilation, central venous or arterial catheterization, and vasoactive and/or inotropic drugs was not significantly different between case patients and controls. This was also the case for ICU mortality and for the mean duration of ICU and hospital stay. Although there was a trend toward a higher hospital mortality among case patients than among controls, it did not reach statistical significance (47% vs 27%, p =.07). CONCLUSION: Our results reinforce the idea that age alone is not a relevant criterion for ICU admission.

Age Factors↗
PubMed2005

Effect of genetically caused excess of brain gamma-hydroxybutyric acid and GABA on sleep.

BACKGROUND: Exogenous gamma-hydroxybutyrate (GHB) increases slow-wave sleep and reduces daytime sleepiness and cataplexy in patients with primary narcolepsy. OBJECTIVE: To examine nighttime sleep and daytime sleepiness in a 13-year-old girl homozygous for succinic semialdehyde dehydrogenase (SSADH) deficiency, a rare recessive metabolic disorder that disrupts the normal degradation of 4-aminobutyric acid (GABA), and leads to an accumulation of GHB and GABA within the brain. METHODS: Sleep interview, nighttime polysomnography, Multiple Sleep Latency Tests, and continuous 24-hour in-lab recordings in the patient; overnight polysomnography in her recessive mother and in a 13-year-old female control. RESULTS: During quiet wakefulness, background electroencephalographic activity was slow and composed of 7-Hz activity. Sleep stage 3/4 was slightly increased (28.1% of total sleep period, norms 15%-28%), and the daytime mean sleep latency was short in the patient (3 minutes 42 seconds, norms > 8 minutes). Stage 2 spindles were infrequent in the child (0.18/minute, norms: 1.2-9.2/minute) and her mother (0.65/minute) but normal (4.6/minute) in the control. At the beginning of the second night, a tonic-clonic seizure occurred, followed by a dramatic increase in stage 3/4 sleep, that lasted 46.3 % of the total sleep period, double the normal value. The mother showed a reduced total sleep time and rapid eye movement sleep percentage. DISCUSSION: This suggests that a chronic excess of GABA and GHB induces subtle sleep abnormalities, whereas increased slow-wave sleep evoked by a sudden event (here an epileptic seizure) may be caused by a supplementary increase in GABA and GHB.

Adolescent↗
PubMed2005

Sequential administration of docetaxel followed by cisplatin-vindesine: a pilot study in patients with locally advanced or metastatic non-small cell lung cancer (NSCLC).

In this phase II study, the feasibility and efficacy of sequential chemotherapy were tested with agents shown to be active as monotherapy. Patients with chemotherapy-naive, locally advanced or metastatic non-small cell lung cancer were selected for the study. Treatment involved four cycles of docetaxel (100 mg/m(2) on day 1, every 3 weeks) (sequence A), followed by four cycles of cisplatin-vindesine (cisplatin 120 mg/m(2) on day 1 and vindesine 3 mg/m(2) on days 1, 8, 15, and 22, every 4 weeks) (sequence B). Responding patients received 3 cycles of docetaxel 100 mg/m(2) (day 1, every 3 weeks) as consolidation (sequence C). Thirty-two patients entered the study with thirty being evaluable for efficacy. Four patients showed a partial response and one patient a complete response, resulting in an objective response rate of 16.7 %. The median survival time (intent-to-treat) was 11 months (95 %CI = 8.0-15.4 months) with an estimated 1-year survival rate of 47%. The median time to progression was 17.6 weeks in the evaluable population. Main grade 4 toxicity was neutropenia (21.8 % and 68.2 % of patients in sequence A and B, respectively) while grade 3 peripheral neuropathy was documented in five patients during sequence B. There were no treatment-related deaths. Sequential chemotherapy may show promise for the treatment of advanced non-small cell lung cancer. Given the feasibility of this pilot study, sequential chemotherapy concept should be investigated with newer cisplatin-based regimens using this approach in larger prospective studies.

Adult↗
PubMed2005

REM sleep behavior disorder and REM sleep without atonia in patients with progressive supranuclear palsy.

STUDY OBJECTIVE: To compare sleep characteristics, rapid eye movement (REM) sleep without atonia, and REM sleep behavior disorder (RBD) in patients with progressive supranuclear palsy (tauopathy), patients with Parkinson's disease (a synucleinopathy), and control subjects. DESIGN: Sleep interview, overnight polysomnography, and Multiple Sleep Latency Tests. PATIENTS: Forty-five age- and sex-matched patients with probable progressive supranuclear palsy, (n=15, aged 68 +/- 8 years, 7 men), patients with Parkinson disease (n=15), and control subjects (n=15). SETTINGS: Tertiary-care academic hospital. INTERVENTION: N/A. RESULTS: Compared to the 2 other groups, patients with progressive supranuclear palsy had a longer duration of wakefulness after sleep onset and twice as much sleep fragmentation and percentage of stage 1 sleep but had similar apnea-hypopnea indexes, periodic leg movements indexes, and mean daytime sleep latencies. REM sleep percentage was as low in patients with progressive supranuclear palsy (8% +/- 6% of total sleep time) as in patients with Parkinson disease (10% +/- 4%), versus 20% +/- 6% in controls (analysis of variance, P < .0001). Interestingly, patients with progressive supranuclear palsy had percentages of REM sleep without atonia (chin muscle activity: 33% +/- 36% of REM sleep) similar to those of patients with Parkinson disease (28% +/- 35%) and dramatically higher than those of controls (0.5% +/- 1%, analysis of variance, P = .008). Four (27%) patients with progressive supranuclear palsy had more than 50% REM sleep without atonia (as did a similar number of patients with Parkinson disease), and 2 of them (13%, vs 20% of patients with Parkinson disease) had clinical RBD. The four patients with progressive supranuclear palsy with excessive daytime sleepiness slept longer at night than the 11 patients with progressive supranuclear palsy who were alert (442 +/- 14 minutes vs 312 +/- 74 minutes, student t tests, P = .004), suggesting a primary nonnarcoleptic hypersomnia. CONCLUSION: REM sleep without atonia and RBD were as frequent in patients with progressive supranuclear palsy as in patients with Parkinson disease. It suggests that the downstream cause of parkinsonism, rather than its primary neuropathology (synucleinopathy vs tauopathy), is a key factor for REM sleep behavior disorder.

Aged↗
PubMed2004

[Diagnosis and management of exacerbations and acute respiratory failure in patients with chronic obstructive pulmonary disease].

Acute episode of chronic obstructive pulmonary disease occurs in almost all patients, during which cough, expectoration and dyspnea increase. When the underlying disease is not severe and the acute episode not life-threatening, the term "exacerbation" is appropriate, and the patients can be managed at home. When the underlying disease is advanced and the acute episode possibly life-threatening, the terms of "acute respiratory failure" or "decompensation" can be used. These patients are most often admitted to the hospital, and at times to the intensive care unit. Bronchodilators and respiratory physiotherapy form the basis of the management of acute episodes of COPD. In severe cases, oxygen must be administered, and the decision of an hospitalisation considered. Antibiotics and corticosteroids shoud not be prescribed in a systematic manner. In the most severe cases, non-invasive ventilation must be accessible. The prevention of acute episodes of COPD is best achieved through tobacco cessation and influenza vaccine. Finally, an acute episode may be an opportunity to make a diagnosis of COPD if this has not been done before.

Acute Disease↗
PubMed2004

Upper airway afferents are sufficient to evoke the early components of respiratory-related cortical potentials in humans.

Repeated inspiratory occlusions in humans elicit respiratory-related cortical potentials, the respiratory counterpart of somatosensory-evoked potentials. These potentials comprise early components (stimulus detection) and late components (cognitive processing). They are considered as the summation of several afferent activities from various part of the respiratory system. This study assesses the role of the upper airway as a determinant of the early and late components of the potentials, taking advantage of the presence of a tracheotomy in patients totally or partially deafferented. Eight patients who could breathe either through the mouth or through a tracheotomy orifice (whole upper airway bypassed) were studied (4 quadriplegic patients with phrenic pacing, 4 patients with various sources of inspiratory pump dysfunction). Respiratory-related evoked potentials were recorded in CZ-C3 and CZ-C4. They were consistently present after mouth occlusions, with a first positive P1 and a first negative N1 components of normal latencies (P1: 40.4 +/- 6.1 ms in CZ-C3 and 47.6 +/- 7.6 ms in CZ-C4; N1: 84.4 +/- 27.1 ms in CZ-C3 and 90.2 +/- 17.4 ms in CZ-C4) and amplitudes. Tracheal occlusions did not evoke any cortical activity. Therefore, in patients with inspiratory pump dysfunction, the activation of upper airway afferents is sufficient to produce the early components of the respiratory-related evoked cortical potentials. Per contra, in this setting, pulmonary afferents do not suffice to evoke these components.

Adult↗
PubMed2003

Expiratory-synchronized sleep in a quadriplegic patient using inspiratory neck muscles to breathe.

In a patient with C3 quadriplegia causing complete diaphragm paralysis who developed inspiratory neck muscles (INM) hypertrophy to sustain ventilation, spontaneous breathing deeply altered sleep architecture, relegating sleep to the expiratory phase of the ventilatory cycle. A polysomnographic recording performed during mechanical ventilation (without INM activity), showed that sleep was abnormal but unaffected by the respiratory cycle. During spontaneous breathing, the polygraphic recordings showed expiratory microsleep episodes, with inspiratory arousals synchronous to bursts of INM activity. This case report illustrates the powerful adaptability of the respiratory and sleep control systems to maintain each vital function.

Adult↗
PubMed2003

Intracortical inhibition and facilitation of the response of the diaphragm to transcranial magnetic stimulation.

Respiratory muscles respond to a subcortical automatic command and to a neocortical voluntary command. In diseases such as stroke or motor neurone disease, an abnormal diaphragmatic response to single transcranial magnetic stimuli can identify a central source for respiratory disorders, but this is not likely to be the case in disorders affecting intracortical inhibitory and facilitatory mechanisms. This study describes the response of the diaphragm to paired transcranial magnetic stimulation. Thirteen normal subjects were studied (age range, 22 to 43 years; 7 men; phrenic conduction, <6.8 msec; latency of diaphragmatic motor evoked potential, <20.5 msec). Motor evoked potentials in response to paired stimulation were obtained in eight subjects only, with the motor threshold in the remaining five subjects too high to absorb the loss of power inherent in the double-stimulation montage. Interstimulus intervals less than 5 msec resulted in a statistically significant inhibition (p < 0.01 for interstimulus intervals of 1 and 3 ms), whereas intervals longer than 6 msec were facilitatory (maximal, 15 msec). The diaphragmatic pattern matched that of the biceps brachii. The authors conclude that it is possible to study intracortical inhibition and facilitation of diaphragmatic control, although not in all subjects. Technical improvement should alleviate current limitations and make paired transcranial magnetic stimulation a tool to study respiratory muscle abnormalities in settings in which intracortical interactions are important, such as movement disorders.

Action Potentials↗
PubMed2003

Simplified method to measure respiratory-related changes in arterial pulse pressure in patients receiving mechanical ventilation.

STUDY OBJECTIVES: Measuring respiratory-related changes in arterial pulse pressure is useful to guide fluid expansion in hemodynamically compromised patients. In the absence of automation, this can be uneasy in clinical practice. The objective of this study was to test an alternative approach (expiratory pause) that should be easier to apply. DESIGN: Prospective observational study comparing two measurement methods of a biological variable. PATIENTS: Seventeen patients receiving mechanical ventilation without spontaneous respiratory activity, with an arterial indwelling catheter, exhibiting respiratory-related fluctuations in arterial pressure. SETTING: Ten-bed respiratory ICU in a 2,000-bed university hospital. INTERVENTION: Analysis of clinically gathered data without specific experimental intervention. MEASUREMENTS: Determinations of the change in arterial pulse pressure observed during ventilatory cycling (Delta Pp,dyn) ["dynamic"] and change in arterial pulse pressure observed during expiratory pauses (Delta Pp,stat) ["static"] were performed to assess respiratory mechanics, and comparison of the two sets of data (correlation, Bland and Altman, Passing and Bablok regression). RESULTS: Delta Pp,dyn and Delta Pp,stat were strongly correlated (R = 0.964; 95% confidence interval, 0.917 to 0.987; p < 0.0001), with a good level of agreement (mean difference, 0.016; lower limit of agreement, - 0.087; upper limit, 0.120) and no systematic difference. CONCLUSION: Measuring respiratory-related Delta Pp,stat provides data that seem interchangeable with Delta Pp,dyn, providing an easy means to routinely obtain this information.

Adult↗
PubMed2002

Comparison of bedside measurement of cardiac output with the thermodilution method and the Fick method in mechanically ventilated patients.

INTRODUCTION: Bedside cardiac output determination is a common preoccupation in the critically ill. All available methods have drawbacks. We wished to re-examine the agreement between cardiac output determined using the thermodilution method (QTTHERM) and cardiac output determined using the metabolic (Fick) method (QTFICK) in patients with extremely severe states, all the more so in the context of changing practices in the management of patients. Indeed, the interchangeability of the methods is a clinically relevant question; for instance, in view of the debate about the risk-benefit balance of right heart catheterization. PATIENTS AND METHODS: Eighteen mechanically ventilated passive patients with a right heart catheter in place were studied (six women, 12 men; age, 39-84 years; simplified acute physiology scoreII, 39-111). QTTHERM was obtained using a standard procedure. QTFICK was measured from oxygen consumption, carbon dioxide production, and arterial and mixed venous oxygen contents. Forty-nine steady-state pairs of measurements were performed. The data were normalized for repeated measurements, and were tested for correlation and agreement. RESULTS: The QTFICK value was 5.2 +/- 2.0 l/min whereas that of QTTHERM was 5.8 +/- 1.9 l/min (R = 0.840, P < 0.0001; mean difference, -0.7 l/min; lower limit of agreement, -2.8 l/min; upper limit of agreement, 1.5 l/min). The agreement was excellent between the two techniques at QTTHERM values <5 l/min but became too loose for clinical interchangeability above this value. Tricuspid regurgitation did not influence the results. DISCUSSION AND CONCLUSIONS: No gold standard is established to measure cardiac output in critically ill patients. The thermodilution method has known limitations that can lead to inaccuracies. The metabolic method also has potential pitfalls in this context, particularly if there is increased oxygen consumption within the lungs. The concordance between the two methods for low cardiac output values suggests that they can both be relied upon for clinical decision making in this context. Conversely, a high cardiac output value is more difficult to rely on in absolute terms.

Adult↗
PubMed2002

Validation of surface recordings of the diaphragm response to transcranial magnetic stimulation in humans.

The integrity of the central efferent motor pathways to the diaphragm can be assessed by using transcranial magnetic stimulation to measure the latency of the corresponding motor evoked potentials with surface electrodes. Because transcranial magnetic stimulation does not activate the diaphragm alone, signal contamination is a potential problem. To evaluate this issue, surface diaphragmatic motor-evoked potential latencies were compared with latencies recorded from diaphragm needle in 9 healthy volunteers. Surface latencies of muscles likely to contaminate the diaphragm signals (serratus anterior, pectoralis major, and tranversus abdominis) were also recorded. The latencies in response to nonfocal transcranial stimulation from surface electrodes were not significantly different from the needle ones (17 +/- 1.3 vs. 17.2 +/- 1.1 ms, respectively) but were significantly different from the latencies of the other muscles. In two cases, signal contamination appeared likely (serratus anterior in 1 case, abdominal muscles in 1 case). It is possible to reliably measure the latency of the diaphragm response to transcranial magnetic stimulation with adequately positioned surface electrodes.

Adult↗