Anesthésie locorégionale chez le patient obèse

Objective

To detail specificity of regional anaesthesia techniques in the obese patient.

Data sources

Articles were selected from Medline database using the combination of the following keywords: obesity, peripheral nerve block, spinal anaesthesia, epidural, morbidity, mortality.

Study selection

Most recent original articles or review have mainly been selected. Some case reports that highlighted specific points were added.

Data extraction

Articles were analyzed for advantages and drawbacks, and risks of different techniques in obese patient.

Data synthesis

Techniques avoiding obese patient's mobilization are recommended. The use of skin landmarks may be challenging for both central and peripheral blocks. Ultrasound techniques should improve block performance, even though deep fat layers seem limit sound diffusion. Success rate and incidence of complications are usually increased after regional anaesthesia technique in obese patient. The reduction of intrathecal local anesthetic dose remains controversial in this population.

Conclusion

Regional anaesthesia techniques could represent an alternative to general anaesthesia (less cardiorespiratory complications). However, many specific considerations have to be taken into account.     

Hypernatrémie chez le patient cérébrolésé : utile ou dangereux ?

Hypernatremia is defined by a serum sodium concentration of more than 145 mmol/L and reflects a disturbance of the regulation between water and sodium. The high incidence of hypernatremia in patients with severe brain injury is due various causes including poor thirst, diabetes insipidus, iatrogenic sodium administration, and primary hyperaldosteronism. Hypernatremia in the intensive care unit is independently associated with increased mortality and complications rates. Because of the rapid brain adaptation to extracellular hypertonicity, sustained hypernatremia exposes the patient to an exacerbation of brain edema during attempt to normalize natremia. Like serum glucose, serum sodium concentration must be tightly monitored in the intensive care unit.     

Pronostic des nouveau-nés de mère prééclamptique

Preeclampsia (PE) is associated with 3 main risks for the fetus: perinatal death, intrauterine growth restriction (IUGR), preterm birth. Perinatal mortality is increased in infants with IUGR or asphyxia. Conversely, mortality and morbidity associated with preterm birth are not altered by PE without IUGR or asphyxia. Very preterm infant with IUGR are exposed to high risk of prolonged respiratory insufficiency. Neurological complications of prematurity are not more frequent in infants born to mothers with PE. Nevertheless birth asphyxia, (i.e. placental abruption) is associated with impaired neurological out-come especially in infants with neonatal encephalopathy. Long term outcome of infants born to mothers with PE is strongly correlated to gestational age. IUGR increases the risk of hypertension and metabolic syndrome in adulthood. Acute fatty liver of pregnancy can by caused by a fetal fatty-acid oxidation disorder.     

Consentement éclairé en anesthésie pédiatrique pour les soins courants et pour la recherche

This short review is aimed at describing the particularities of consent in paediatric patients. For routine procedures, the consent of one of the parents is required whereas both parents should sign the consent for research protocols. In case of difficulties such as Jehovah witnesses or parental opposite opinions, doctors should ask the question to the judge in charge of protection of children. Consent or at least assent of minors enrolled in research protocols should be obtained provided their maturity is sufficient to understand correctly the purpose of clinical research.     

Phénotypage métabolique par résonance magnétique nucléaire pour l’évaluation périopératoire et en réanimation

Metabolic phenotyping consists in the identification of subtle and coordinated metabolic variations associated with various pathophysiological stimuli. Different analytical methods, such as nuclear magnetic resonance, allow the simultaneous quantification of a large number of metabolites. Statistical analyses of these spectra thus lead to the discrimination between samples and the identification of a metabolic phenotype corresponding to the effect under study. This approach allows the extraction of candidate biomarkers and the recovery of perturbed metabolic networks, driving to the generation of biochemical hypotheses (pathophysiological mechanisms, diagnostic tests, therapeutic targets…). Metabolic phenotyping could be useful in anaesthesiology and intensive care medicine for the evaluation, monitoring or diagnosis of life-threatening situations, to optimise patient managements. This review introduces the physical and statistical fundamentals of NMR-based metabolic phenotyping, describes the work already achieved by this approach in anaesthesiology and intensive care medicine. Finally, potential areas of interest are discussed for the perioperative and intensive management of patients, from newborns to adults.     

Risque allergique en anesthésie pédiatrique

Objectives

To propose the different modalities of management of the allergic risk occurring during paediatric anaesthesia.

Study design

Literature analysis.

Methods

Literature research using the Medline^® database and MeSH format according to keywords, including publications in French and English since 1982.

Results

The overall incidence for anaphylactic reactions was estimated at one in 7741 anaesthetic procedures during paediatric anaesthesia. Latex anaphylaxis was mostly involved with an incidence at one in 10,159 anesthetic procedures. The risk factors of latex sensitization are known. Primary latex prophylaxis is efficient in patients at risk of latex sensitization. In contrast to adults, neuromuscular blocking agents (NMBAs) are rarely involved in children, with an incidence at 1 in 81,275 anaesthetic procedures. The Ring and Messmer clinical scale allows quantifying the severity and helps managing the care of immediate hypersensitivity reactions. Clinical symptoms associate cardiovascular, respiratory and cutaneous-mucous signs according to different severity grades. Epinephrine associated to fluid loading, remains the first-line agent in case of severe reactions. The allergological assessment is key to the management of these reactions and is required in order to identify the mechanism of the reaction and the culprit drug or substance involved.

Conclusions

Allergic reactions to NMBAs occurring during paediatric anaesthesia are rare whereas those with latex are more frequent. Therefore, the reduction of the allergic risk during paediatric anaesthesia essentially requires a latex-free environment.     

Gestion des voies aériennes supérieures en fin d’accouchement : enquête de pratique

Objective

To describe the airway management during general anaesthesia performed at the end of labour.

Study design

Observational retrospective study in a French university obstetrical unit.

Patients and methods

All parturients who underwent general anaesthesia for manual removal of the placenta or instrumental delivery were included. Demographic data, anaesthesia management, indication and duration of anaesthesia were recorded. Incidents as vomiting, a drop in oxygen saturation of five points or more, aspiration and difficult endotracheal intubation were investigated.

Results

Among 111 parturients with inclusion criteria, the rate of tracheal intubation was 5%. The duration of anaesthesia ranged from five to 60 minutes (mean duration: 16 min). No incident was recorded within the methodological limits of this retrospective study.

Conclusion

There is a major discrepancy between guidelines and clinical practice in our unit concerning systematic tracheal intubation during general anaesthesia performed at the end of labour. A national survey is in process to confirm these results.     

Pour ou contre les halogénés en neuroanesthésie pour chirurgie intracrânienne

Isoflurane, desflurane and sevoflurane all preserve cerebrovascular carbone dioxide (CO₂) reactivity. They are all concentration-dependant cerebral vasodilatators and decrease cerebral metabolism. Sevoflurane induces the smallest cerebral vasodilatation and preserve cerebral autoregulation up to 1.5 CAM, compared to isoflurane and desflurane which impair it upon 1 CAM. Propofol has been compared to inhaled agents. Propofol preserve cerebrovascular CO₂ reactivity, blood flow-metabolism coupling, cerebral autoregulation and has no vasodilatation effect. None of the three inhaled agents induce any clinical relevant increase of intracranial pressure (ICP), but studies were conducted in patients without any intracranial hypertension (ICHT). However, compared to propofol, ICP and brain swelling were higher with inhaled agents, more with isoflurane compared to sevoflurane. Finally, neuroprotective properties have been described in experimental model for all the inhaled agents but clinical proofs are still lacking. In conclusion, for intracranial surgery without any ICHT inhaled agents can be used as a maintenance anesthetic with a preference for sevoflurane. In case of ICHT or a risk of ICHT during the surgery, propofol is preferred for it slightest effect on ICP and cerebral hemodynamic.     

Hématome rétroplacentaire

Retroplacental haematoma (RPH) is a complication affecting 0.25 to 0.4% of all pregnancies and 4% of severe PEs. It is of acute onset, usually unpredictable and its symptoms are not specific: Isolated metrorrhagia, foetal distress, uterine hypertonicity. Clinical, biological and sonographic features suggesting a RPH can be early or late. Haemoconcentration and the forming of notches on Doppler examination of the uterus can appear weeks before the event, whereas raised D-Dimers and foetal tachycardia are identified within days of the event. Although Caesarian section reduces the perinatal death rate by 20 to 50% in a setting of RPH with a live foetus, vaginal delivery is indicated in cases of RPH with fetal demise, following the control of haemorrhagic shock, clotting disorders and uterine hypotonicity.     

Évaluation des régulateurs de débit passifs utilisés pour la perfusion intraveineuse

Objective

The aim of our study is to evaluate seven flow rate regulators (FRR) to assess the reliability of these devices compared to standard perfuser with roller clamp.

Study design

Each FRR was tested with 5% dextrose and 0.9% sodium chloride combined with three different theoretical flow rates (30, 80 and 250 ml/h). Accuracy was compared with the theoretical value. Repeatability of flow rate was assessed thanks to variance break-up.

Results

Each FFR exhibits at least one combination “flow rate–solution” significantly different of the theoretical flow rate. Exadrop^® was the least successful of the FFR according to the accuracy. This FFR had for each combination a flow rate different of the theoretical (mean error: −24.0 ml/h). Tutodrop^® was the most successful of the FFR according to the accuracy with five combinations comparable to the theoretical value (mean error: −1.2 ml/h). The standard perfuser with roller clamp, used without FRR, reported two combinations comparable to the theoretical value and showed lowest rates for repeatability.

Conclusion

Our study exhibits the poor performances of the FRR studied: according to expected flow regulation, the reported results demonstrate the lack of accuracy. Their only one value added compare to the roller clamp is to improve the repeatability of the flow rate.