mercredi 5 février 2020 

14h10 - 15h10


 
Forum 3

Pédiatrie I

MODÉRATEUR(S) :  Philippe JOUVET (Montréal, CANADA ), Fabrice MICHEL (Marseille)  
  

Assessment of diaphragmatic function in mechanically ventilated children using the neuromuscular efficiency index

Orateur(s) :   Benjamin CRULLI (Montréal, CANADA) 

Auteur(s) :  Guillaume EMERIAUD (Montreal, CANADA)  

14h10 - 14h18
Durée de la présentation : 5 min
Durée de la discussion : 3 min


Abstract : 
Assessment of diaphragmatic function in mechanically ventilated children using the neuromuscular efficiency index

Introduction / Rationale :
Ventilator induced diaphragmatic dysfunction is highly prevalent in adult critical care and associated with worse outcomes. Specificities in pediatric respiratory physiology suggest that critically ill children may be at high risk of developing this complication, but no study has described the evolution of diaphragmatic function in critically ill children undergoing mechanical ventilation. This study aims to validate a method to quantify diaphragmatic function in mechanically ventilated children.

Méthodes / Patients and Methods :
In this prospective single-center observational study, 10 children between 1 week and 18 years old intubated for elective ENT surgery and without pre-existing neuromuscular disease or recent muscle paralysis were recruited. Immediately after intubation, diaphragmatic function was evaluated using brief airway occlusion maneuvers during which airway pressure at the endotracheal tube (Paw) and electrical activity of the diaphragm (EAdi) were simultaneously measured for 5 consecutive spontaneous breaths, while the endotracheal tube was occluded with a specific valve. Occlusion maneuvers were repeated 3 times. In order to account for central respiratory drive and sedation use, we recorded the neuromechanical efficiency ratio (NME, Paw/EAdi), in addition to the maximal inspiratory force (MIF). In order to determine the optimal measure of NME during an occlusion, the variability over the three occlusion maneuvers of different variables (first breath, last breath, breath with maximal Paw deflection, breath with maximal NME value, and median NME value) was assessed using coefficients of variation and repeatability coefficients.

Résultats / Results :
Patients had a median age of 4.9 years (interquartile range 3.9-5.5), a median weight of 18 kg (14-23), and 5 were male (50%). The median evolution of Paw, EAdi, and NME ratio over the 5 occluded breaths are represented on Figure 1. NME values corresponding to the last breath and the breath with maximal Paw deflection were the least variable, with median coefficient of variation of 23% and 23% and repeatability coefficients of 3.44 and 3.44, respectively.

Discussion / Discussion :


Conclusion / Conclusion :
Brief airway occlusions can be used to assess diaphragmatic function in intubated children through both MIF and NME ratio, and the latter should ideally be computed on the last breath or the breath with the largest pressure deflection to improve repeatability and decrease variation.
 

Efficacy and safety of dexmedetomidine as sole sedation for children undergoing MRI in comparison to general anesthesia: a single-center retrospective study (DEX-IRM).

Orateur(s) :   Hélène LEPELTIER (Caen) 

Auteur(s) :  Arnaud LEPETIT (Caen)   Maxime GAUBERTI (Caen)   Clément ESCALARD (Caen)   Anne LESAGE (Caen)   David BROSSIER (Caen)   Isabelle GOYER (Caen)  

14h18 - 14h26
Durée de la présentation : 5 min
Durée de la discussion : 3 min


Abstract : 
Efficacy and safety of dexmedetomidine as sole sedation for children undergoing MRI in comparison to general anesthesia: a single-center retrospective study (DEX-IRM).

Introduction / Rationale :
MRI requires prolonged motion-free periods. This may be difficult to obtain in the pediatric patient population. This need for prolonged immobility justifies the use of general anesthesia or procedural sedation in children. Recently, national drug safety agencies have warned physicians about the risk of neurotoxicity of conventional anesthetic agents targeting GABAergic and glutamatergic neurotransmission pathways in children. Dexmedetomidine, a sedative agent with works as an α2 pre-synaptic receptor agonist, does not act on these usual pathways. This molecule has raised great interest in the procedural sedation of children, especially since it preserves respiratory drive. The objective of this study was to evaluate the efficacy and safety of dexmedetomidine sedation in pediatric MRI compared to conventional general halogenated anesthesia.

Méthodes / Patients and Methods :
This was a retrospective monocentric cohort study performed in the University Hospital of Caen. This study included all patients under 18 years of age who received sedation for MRI between August 1st, 2018 and March 31st, 2019. Patients were retrospectively divided into 2 groups according to the performed sedation modality (DEX and GA).

Résultats / Results :
78 patients were included (26 in the DEX group and 52 in the AG group). Dexmedetomidine sedation was significantly associated with a decrease in the use of invasive ventilation (p<0.001) with no difference in image quality. The failure rate of sedation was 42% in the DEX group vs. 0% in the AG group (p<0.001). None of the patients had any significant adverse reactions to dexmedetomidine.

Discussion / Discussion :


Conclusion / Conclusion :
Dexmedetomidine seems suitable for procedural sedation during MRI in children. It provides an alternative to halogenated general anaesthesia with the aim of limiting children's exposure to conventional anaesthetic agents and the use of invasive ventilation.
 

Incidence of withdrawal syndrome after sedation/analgesia in a surgical pediatric intensive care units using the Withdrawal Assessment Tool-1 (WAT-1) score

Orateur(s) :   Pauline PONSIN (Paris) 

Auteur(s) :  Guillaume GESLAIN (Paris)   Chloé TRIDON (Paris)   Charline RIAUD (Paris)   Nicolas ROBIN (Paris)   Alina LAZARESCU (Paris)   Gilles ORLIAGUET (Paris)  

14h26 - 14h34
Durée de la présentation : 5 min
Durée de la discussion : 3 min


Abstract : 
Incidence of withdrawal syndrome after sedation/analgesia in a surgical pediatric intensive care units using the Withdrawal Assessment Tool-1 (WAT-1) score

Introduction / Rationale :
Withdrawal syndrome (WS) is a known side effect of prolonged sedation/analgesia in pediatric intensive care units (PICU). Epidemiology is poorly understood due to the rare use of validated diagnostic tools. The main objective of the study was to determine, by systematically calculating the WAT-1 score, the incidence of WS in our surgical PICU. The secondary objective was to analyze the risk factors, consequences and management modalities of WS.

Méthodes / Patients and Methods :
Following Institutional Review Board approval, we conducted a prospective monocentric study between July 2018 and January 2019. All consecutive mechanically ventilated children admitted in our surgical PICU with sedation/analgesia by continuous intra-venous (IV) benzodiazepines (BZD) and/or opioids for at least 48 hours were included. As soon as sedation was decreased and during 72 hours following their total discontinuation, WAT-1 score was assessed twice a day. WS was defined by a WAT-1 score >3. The search for risk factors and consequences associated with WS was performed by univariate analysis (Mann-Whitney and Chi2 test). Ethical standards were satisfied and the lack of opposition from patients and their parents was systematically checked.

Résultats / Results :
The incidence of WS was 50% among the 46 patients of our cohort including 54% of children admitted postoperatively and 35% after severe traumatic brain injury (TBI). Significant results are reported in Table 1. Our results show that even for sedation time less than 5 days, children could develop WS (11/23 patients). On the other hand, age, severity (PELOD 2 score), number of previous surgeries and severe TBI were not associated with WS. Our study also demonstrated that cessation of sedation and prevention of WS was not uniform in our unit.

Discussion / Discussion :


Conclusion / Conclusion :
The high incidence of withdrawal syndrome in our study, even in children sedated for less than 5 days, and its consequences require thinking about prevention. We suggest a systematic monitoring of the occurrence of this adverse event using a validated score, from 3 days of continuous IV sedation/analgesia.
 

Automatic Real-time Classification of the Validity of Intracranial Pressure Signals Recorded by Ventricular Drain Using a Machine Learning Method

Orateur(s) :   Sally AL OMAR (Montréal, CANADA) 

Auteur(s) :  Floriane CANNET (Marseille)   Gabriel MASSON (Lille)   Philippe JOUVET (Montreal, CANADA)   Guillaume EMERIAUD (Montreal, CANADA)  

14h34 - 14h42
Durée de la présentation : 5 min
Durée de la discussion : 3 min


Abstract : 
Automatic Real-time Classification of the Validity of Intracranial Pressure Signals Recorded by Ventricular Drain Using a Machine Learning Method

Introduction / Rationale :
Severe traumatic brain injury (TBI) is a major healthcare problem. Amplitude and duration of intracranial hypertension is highly associated with patient outcome. The intracranial pressure (ICP) is therefore one key parameter to monitor in the acute phase. When ICP is monitored with an external ventricular drain, the pressure recorded by the monitor does not always correspond to the real ICP, depending on the status (open/closed) of the 3-way tap. Misleading values could therefore be sent to the patient medical record. Our hypothesis is that a machine-learning algorithm will be able to identify automatically and in real time the reliable and non-reliable values of the ICP signal.

Méthodes / Patients and Methods :
We retrospectively studied pediatric patients having an external ventricular drain between July 2018 and July 2019, in a single pediatric intensive care unit. The ICP signals were extracted from a high-frequency database (128 Hz) and pre-processed adequately. To train the algorithms, an annotated database was manually created with two classes: reliable ICP vs. non-reliable ICP (drain system opened to allow cerebrospinal fluid removal). Eleven signal characteristics were compared between the two classes (Mann-Whitney test), and significantly differing variables were tested in the algorithms. We compared the performance of two machine-learning algorithms: the K-Nearest Neighbors (KNN) and the Support Vector Machine (SVM). Using 10-fold cross-validation method, 75% of the data was used to train the algorithms and 25% was used for testing. The best classifier was further validated by simulating a real-time ICP analysis, using a 15s sliding-window approach with 50% overlap. The study was approved by the local research ethics committee.

Résultats / Results :
Sixteen patients were included in the study. The training database created from 14 patients, contained 320 segments (of 15s duration) per class and per patient. Eight signal variables were identified and kept to define the segments. The KNN algorithm, with k=3, led to the best performance, with a mean of 98% (mean±std: 98% ± 0.29%). The KNN was then visually validated on ICP signals from the remaining two patients (Figure). By simulating a real-time ICP extraction, our algorithm was able to efficiently identify the reliable ICP segments, and to display a mean value only for valid segments.

Discussion / Discussion :


Conclusion / Conclusion :
The proposed machine learning algorithm can help identifying the validity of ICP values recorded using a ventricular drain in real time. After external validation, this algorithm could be implemented in future clinical decision support system to optimize the care of TBI patients.
 

Epidemiology and prognosis of acute encephalitis in pediatric intensive care unit

Orateur(s) :   Hélène LIENARD (Paris) 

Auteur(s) :  Jérôme NAUDIN (Paris)   Florence RENALDO (Paris)   Fleur LE BOURGEOIS (Paris)   Anna DEHO (Paris)   Maryline CHOMTON (Paris)   Géraldine PONCELET (Paris)   Guillaume GESLAIN (Paris)   Stéphane DAUGER (Paris)   Michaël LEVY (Paris)  

14h42 - 14h50
Durée de la présentation : 5 min
Durée de la discussion : 3 min


Abstract : 
Epidemiology and prognosis of acute encephalitis in pediatric intensive care unit

Introduction / Rationale :
Acute encephalitis is a rare but potentially severe disease leading to an admission in Pediatric Intensive Care Units (PICU) in 18 to 40% of pediatric patients. However, there are few epidemiological data on these severe forms and little is now about their outcome. The main objective of this study was to describe the etiologies of acute encephalitis in PICU as well as their presentations. Secondary objectives included an evaluation of the outcome (mortality and sequalae) as well as related risk factors of poor outcome.

Méthodes / Patients and Methods :
A monocentric retrospective study was performed between January 2005 and December 2018 in Robert-Debré University Hospital PICU (Paris). All consecutive children (1 month – 18 years) admitted for acute encephalitis were included and diagnosis was confirmed using the 2013 consensus conference criteria’s. Data regarding clinical, biological and radiological presentations were collected as well as data on the therapeutics used and outcomes at discharge and at the last medical consultation.

Résultats / Results :
106 patients were included with a mean age of 6,2 years (range 0,1 to 17 years old). Infectious causes were identified in 45% (n = 48), autoimmune causes in 8% (n = 8) and acute demyelinating encephalomyelitis in 4% (n=4) of cases. Etiology remained undetermined in 43% of cases (n= 46). The most common pathogens were, in order of frequency, Influenzae virus, Mycoplasma pneumoniae and Epstein-bar virus. The main clinical features were fever (88% n = 93); epileptic seizures (80% n =85) and coma (46% n = 49). Regarding therapeutics, 52 % of patients required mechanical ventilation and 20 % of patients required hemodynamic support. 47% received corticosteroids, 17% intravenous immunoglobulins and 12% plasmatic exchanges. The use of these specific treatments was heterogeneous, especially in infectious and undetermined encephalitis, where respectively 48% and 38% received boluses of corticoids. The mean length of stay in PICU was 10,7 days (range 1 – 155 days). The mortality rate was 10% and the overall rate of sequelae at discharge was 76% and 61% at distance, with 21% considered as severe (GOSE-PED score >5). The use of mechanical ventilation and young age at diagnosis were risk factors associated with poor prognosis at discharge.

Discussion / Discussion :


Conclusion / Conclusion :
The etiology of acute encephalitis remains indeterminate in more than 40% cases with a clear predominance of infectious causes when an etiology is found. This is a severe pathology responsible for significant mortality and morbidity requiring long-term follow-up.
 

Prognostic value of cerebral oxymetry in critically ill children undergoing extracorporeal membrane oxygenation

Orateur(s) :   Meryl VEDRENNE (Paris) 

Auteur(s) :  Raphaël LÉVY (Paris)   Judith CHAREYRE (Paris)   Manoëlle KOSSOROTOFF (Paris)   Sylvain RENOLLEAU (Paris)   Marion GRIMAUD (Paris)  

14h50 - 14h58
Durée de la présentation : 5 min
Durée de la discussion : 3 min


Abstract : 
Prognostic value of cerebral oxymetry in critically ill children undergoing extracorporeal membrane oxygenation

Introduction / Rationale :
Preserving neurological outcome of children under Extracorporeal Membrane Oxygenation (ECMO) remains challenging. Acute Brain Injury (ABI) is a frequent complication of ECMO that could be prevented by continuous neuromonitoring. Cerebral Near InfraRed Spectroscopy (NIRS) is routinely used for detecting cerebral complications of cardiac surgery. In adults and infants under prolonged ECMO, cerebral hypoxia is associated with poor neurological outcome. The aim of this study was to assess the value of an impaired cerebral oxygenation on mortality and occurrence of an ABI in children under ECMO.

Méthodes / Patients and Methods :
Children under 18 years old were included in this observational retrospective monocentric study if they needed veno-venous (V-V) or veno-arterial (V-A) ECMO for respiratory and/or circulatory failure and had concomittant NIRS monitoring. Cerebral desaturation was defined as a rScO2 value under 50% or under 20% from the baseline; cerebral hyperoxia was defined as a rScO2 value above 80%. Proportion of time in cerebral desaturation and hyperoxia were recorded. Neurological lesions were identified on imaging (MRI or scan) by blinded radiologist and classified as major or minor. ABI was defined as any hemorragic or ischemic lesion on cerebral imaging, including brain death.

Résultats / Results :
63 patients were included. ECMO duration was 9 [5; 13] days. The mortality rate was 32 (50,8%), and the proportion of ABI was 34 (54%) including 5 brain deaths, 10 (15,9%) major lesions, and 19 (30,2%) minor lesions. Mean rScO2 was 73±9 % in the right hemisphere, and 75±9% in the left hemisphere. There was no significant difference in cerebral hypoxia between survivors and non survivors, and between patients with and without an ABI. Cerebral hyperoxia was associated with a better survival (p=0,03 in the right hemisphere, and p=0,02 in the left hemisphere). In V-V ECMO and at the right hemisphere, proportion of patients in hyperoxia was higher in survivors (78 [72; 81,8]% versus 58 [56;70]%, p=0,04); proportion of time in hyperoxia was also more important (42 [12; 57] % in survivors versus 4,5 [0; 23,3]% in non survivors, p=0,049).

Discussion / Discussion :


Conclusion / Conclusion :
In our study, cerebral hypoxia was not associated with poor neurological outcome, but cerebral hyperoxia seems to be protective especially in V-V ECMO. This is the first study assessing the value of cerebral oxymetry in all age ranges pediatric ECMO. In this population, multimodal monitoring might be better than NIRS alone to predict neurological impairment. Further prospective studies are needed to assess first the feasibility, then the impact of such a monitoring.
 

Cerebral autoregulation impairment is associated with acute neurological events during pediatric extracorporeal membrane oxygenation

Orateur(s) :   Nicolas JORAM (Nantes) 

Auteur(s) :  Erta BEQIRI (Cambridge)   Stefano PEZZATO (Genoa, ITALIE)   Pierre BOURGOIN (Nantes)   Alexis CHENOUARD (Nantes)   Jean-Michel LIET (Nantes)   Marek CZOSNYKA (Cambridge)   Pierre-Louis LEGER (Paris)   Peter SMIELEWSKI (Cambridge)  

14h58 - 15h06
Durée de la présentation : 5 min
Durée de la discussion : 3 min


Abstract : 
Cerebral autoregulation impairment is associated with acute neurological events during pediatric extracorporeal membrane oxygenation

Introduction / Rationale :
Children supported by extracorporeal membrane oxygenation (ECMO) present a high risk of adverse neurological complications. As some animal studies have shown, cerebral autoregulation (CA) impairment after exposure to ECMO, may be a key factor. Our main objective was to investigate the feasibility of CA continuous monitoring during ECMO treatment. The second objective was to analyze the relationship between CA impairment and neurological outcome.

Méthodes / Patients and Methods :
An observational prospective study including children treated by ECMO in 2 centers was conducted. A correlation coefficient between the variations of regional cerebral oxygen saturation (rScO2) and the variations of mean arterial blood pressure (MAP) was calculated as an index of CA (cerebral oxygenation reactivity index, COx) during ECMO. A COx> 0.3 was considered as indicative for dysautoregulation. COx values were averaged inside 2 mmHg-MAP bins, allowing determining optimal MAP (MAPopt) and lower (LLA) and upper (ULA) limits of autoregulation in 8-hours periods. Neurological outcome was assessed by the onset of an acute neurologic event (ANE) defined by occurrence of hemorrhagic or ischemic stroke and/or clinical or electrical seizure and/or brain death during the ECMO treatment.

Résultats / Results :
Twenty nine patients (31 ECMO runs) treated by veno-arterial (VA, n=23) or veno-venous ECMO (VV, n=6) were included (median age 71 days, weight 4.6 kg). COx was always available in all patients and MAPopt, LLA and ULA in 89.8 % of time. CA variables were similar during VA and VV ECMO runs. Among children who presented ANE (15/29, 51.8%) versus others, the median time spent with a COx > 0.3 was significantly higher (33% (23.5-64.2) vs 20% (16.6-23.7), p<0.001). These patients spent also significantly more time with MAP below LLA (10.4% (6.1-26.8) vs 5.2% (1.8-9.2), p=0.03). After adjustment on the onset of cardiac arrest before or during cannulation and the type of ECMO (VA vs VV), percentage of time spent with a Cox > 0.3 higher than 25% was independently associated with ANE (aOR 8.03, IC 95% 1.02-63.12, p=0.04)

Discussion / Discussion :


Conclusion / Conclusion :
CA assessment seems to be feasible in pediatric ECMO. The impact of the time below autoregulation threshold on neurological outcome is significant. However, the underlying mechanisms of CA impairment during ECMO need to be explored further.