Lésions ischémiques secondaires : comment les prévenir ?

In addition to the initial lesions related to the brain injury, the final outcome depends also largely on the secondary ischaemic lesions. These lesions result from hypoperfusion whatever the mechanisms. It is then essential to detect early the conditions at risk of ischaemia, to be treated aggressively since the initial care. The multimodal monitoring is the only way to diagnose these conditions, to provide information about the mechanisms, and then to better adapt the treatment. Such an early detection helps to limit the consequences of the initial trauma, and may improve outcome.     

Anesthésiques locaux : qu'apportent les formes lévogyres ?

The use of levobupivacaine and of ropivacaine may increase the safety of regional anaesthesia. These pure enantiomers have similar pharmacokinetic properties as those of the racemic mixtures. However, they are less cardiotoxic than the racemic mixtures, especially at the high heart rate usually encountered in infants. We may then recommend the use of these agents in the paediatric patients.     

Quelle bithérapie antihypertensive optimale pour les patients néphrologiques ?

In this editorial review on the optimal antihypertensive treatment for chronic kidney disease (CKD) patients, we start with the controversy triggered by Casas et al., for proposing a bitherapy optimal not only for nephroprotection, but also for global cardiovascular protection. The incidence of cardiovascular complications are indeed much greater than the occurrence of end stage renal disease (ESRD) in these patients, so that their prevention has at least the same priority. We explain the huge amount of discordant papers, on the basis of methodology deficiencies in the studies aiming at evidencing the truth of 2 antinomic concepts underlying this controversy: 1) "The correction by antihypertensive drugs of the cardiovascular risk excess in hypertensive patients is exclusively related to their blood pressure lowering effect, the optimal blood pressure (BP) level being defined by epidemiologists at 115/75 mmHg"; 2) "Independently of BP lowering effect, antihypertensive drugs may have intrinsic, protective or deleterious, renal and cardiovascular effects which may be variable according to the target organ". We think that truth is conciliating and that both mechanisms should not be exclusive. However more rigorous studies are still needed to evidence it. Meanwhile we propose the optimal therapy by hypokaliemic diuretics (thiazides+/-loop diuretics according to glomerular filtration decline)+inhibitors of the angiotensin AT1-receptor (ACE inhibitors or AT1RB), in preference to the association of dihydropyridines with diuretics. This recommendation is strong however, only for CKD patients with macroproteinuria. The priority that we give to diuretic therapy is based on the evidence that this class confers good prevention against both heart failure and strokes, which is not the case for all AT1-inhibitors and dihydropyridines. Furthermore the diuretics are the drugs with the longest antihypertensive effect (many weeks) and their efficiency in CKD patients is proportional to the sodium depletion they initially induce and therefore to the dose (specially of the loop diuretics). Indeed volemia control is an incontrovertible factor for optimal BP control in renal insufficiency. As regards the use of betablockers, they should no more be considered as first drug for hypertension because they have the strongest diabetogenic effect. They should be used selectively for their specific cardiologic indications such as angina, heart failure, arythmia and as substitute for ACEI or AT1RB when general anesthesia is considered. Regarding the choice between ACEI and AT(1)RB, on the basis of indirect comparisons, we think that the latter may grant a comparable cardiac protection while giving a better cerebral protection. We shall have to wait the results of ONTARGET study to have or not the evidence for this preference. Finally, we want to stress the necessity to individualize the treatment by taking into account coexistence of cardiovascular complications and of other diseases, as well as the tolerance of the treatment (which may be influenced by seasons, in particular the canicula one), and the cost of the drugs.     

Induction au masque facial avec le sévoflurane chez l'enfant : le point sur les nouvelles modalités

The delay for loss of consciousness can be shortened by using high concentration sevoflurane > 6% and by adding N2O during inhalation induction with sevoflurane in paediatrics. Mean time for tracheal tube insertion is lower than 5 min in the majority of studies. This shorter delay is not associated with any significant increase in clinical side effects. However, recent studies have demonstrated the epileptogenic effect of high effect site sevoflurane concentration (occurrence of spike wave on the EEG). Inhalation induction with high alveolar sevoflurane concentration is questionable mainly when it is associated with hyperventilation. Positive pressure ventilation or pressure support ventilation make it possible to maintain normocapnia and to monitor FeSevo. Adding a narcotic decreases the target cerebral concentration required to perform tracheal intubation and consequently the risk of spike wave occurrence.     

Pressothérapie préventive précoce pour les greffes extensives au niveau facial chez l'enfant,retour aux méthodes classiques ? Une étude rétrospective sur huit cas

INTRODUCTION: One of the common techniques in the treatment of giant facial naevi is the excision covered by a skin graft. It's functional and esthetic results are not always excellent. Physiotherapy including immediate postsurgical preventive pressure therapy could ameliorate these results and shorten the period of scarring. PURPOSE: Evaluation of scarring results with early pressure therapy in skin grafts of congenital facial naevi. PATIENTS AND METHODS: Retrospective study on 8 children being 1 to 9 years old and presenting congenital facial naevi. All of them were treated by excision followed by full thickness skin grafting. The associated physiotherapy was realized by a transparent rigid or elastic mask. The pressure was started after skin graft uncovering between 7 and 20 days. The period for this treatment was depending on the maturing of the scar. Evaluation was established by 3 examinators on: time till scar maturing, trame quality and esthetic quality. RESULTS: The period till definitive scar maturing was showed to be between 8 and 14 month; trame quality was mostly evaluated as excellent, the esthetic result oscillated between good and medium. CONCLUSION: Physiotherapy seems to be an essential association for the treatment of facial full thickness skin grafts in children. Early pressure therapy could better the functional and esthetic result and accelerate scar maturing. Simple skin grafting could become the first treating option in this indication. Future prospective studies are expected to confirm these results.     

Médiatisation et « greffe de visage » ou « à qui appartient la greffe de visage » ?

Mediatisation of a scientific event could be neither controlled, nor verifiable. The experience which has been lived through the first worldwide allotransplantation of composite tissues of the face confirms that the actors of a surgical innovation are not the owners. Because there is neither confidentiality nor possible patent. Curiously the scientific world, providing with a sharing ethic, which rightly privileges the free spreading of knowledge in the way that most people could benefit of it. Obviously it is made without denied controversy, for truth as purpose. This scientific word that way joins the media one, with a specific ethic of the duty of information, but also interested in mercantile preoccupations quick to cultivate controversy not to enlighten this truth but to better sell pictures or papers. Than the author should only sustain this instrumentation which could certainly flatter him, and from which he could used, but in reality that paralysed him a little to go on in serenity with his shadow worker way.     

Anesthésiques généraux en pédiatrie : risque ou bénéfice ?

The practice of paediatric anaesthesia has changed during the last 25 years, with a noticeable reduction of mortality and serious morbidity. This improvement results in part from the use of new anaesthetic agents which large therapeutic interval regarding cardiovascular effects. Parallel to this advance and following experimental or clinical studies in neurosciences, some new concerns have emerged regarding short and long time consequences of anaesthesia. Indeed, postoperative hyperalgesia due to opioids, emergence agitation and postoperative maladaptive behavioural changes are widely described in children, in the same way the potential epileptogenic effect of sevoflurane is demonstrated. Thus the hypothetical cerebral toxicity leads us to reconsider our practice. Basically, monitoring of cerebral cortical effects of hypnotics is now possible from automated devices based on EEG, allowing us to control the administration of hypnotic agents. The therapeutic interval of these agents, previously determined between movement at incision and deleterious cardiovascular effect, may be revisited with a cerebral approach, with the risk of memorisation for the lower limit and the risk of cerebral over dosage for the upper limit. Lastly, further experimental and clinical studies are required to analyse the effects of the anaesthetic agents on the brain of the neonate, and the interest of the cerebral monitoring in this population.     

Néfopam en perfusion continue et effets secondaires indésirables : quelle imputabilité ?

We report the case of a 77-year-old man, with nefopam postoperative analgesia, who developed subacute neurological symptoms, whereas he had profound hypoprotidemia and acute renal failure. Chronological, semiological and bibliographical criteria are in favour of causality assessment. The plasma nefopam concentration (135 ng/ml) during the neurological symptoms is another argument.     

L’admission du sujet âgé en réanimation : l’âge influence-t-il l’accès aux soins ?

Objectives

The life expectancy of the population increasing, contrary to the resources of beds in reanimation, the question of the admission of the old subject in reanimation is increasingly frequent. We will be interested in the role of the age in the medical decision-making.

Patients and methods

A questionnaire was sent to the intensivists of the same department, then the troop of the subjects refused within an intensive care of the University Hospital of this same department was studied.

Results

The age arrives in third place among the factors of refusal of admission quoted. It does not seem to be an appalling criterion for access to intensive care, but rather to lead to a thorough evaluation of the patient. This idea is translated in the open questions as in the clinical settings in situation. The age modulates the recourse to the entry in intensive care. It tends to be integrated in a total process of evaluation of a patient, even if the consensus is not total… The analysis of the troop of the refused subjects showed a first reason for refusal which is the lack of place. The age is not quoted.

Conclusion

The age does not seem a determining element. It cannot solve the question which is to know if the admission in reanimation is relevant or not for the patient proposed. More than the admission or not of a possibly old subject in reanimation, the problem lies in the resolution with accuracy of the acute dilemma which is the decision-making to admit or refuse a patient whatever it is for the benefit of the person.     

Qu'apporte le modèle de Stewart à l'interprétation des troubles de l'équilibre acide–base ?

Objectives

To explain the different approaches for interpreting acid-base disorders; to develop the Stewart model which offers some advantages for the pathophysiological understanding and the clinical interpretation of acid-base imbalances.

Data source

Record of french and english references from Medline^® data base. The keywords were: acid-base balance, hyperchloremic acidosis, metabolic acidosis, strong ion difference, strong ion gap.

Data extraction

Data were selected including prospective and retrospective studies, reviews, and case reports.

Data synthesis

Acid-base disorders are commonly analysed by using the traditionnal Henderson-Hasselbalch approach which attributes the variations in plasma pH to the modifications in plasma bicarbonates or PaCO₂. However, this approach seems to be inadequate because bicarbonates and PaCO₂ are completely dependent. Moreover, it does not consider the role of weak acids such as albuminate, in the determination of plasma pH value. According to the Stewart concept, plasma pH results from the degree of plasma water dissociation which is determined by 3 independent variables: 1) strong ion difference (SID) which is the difference between all the strong plasma cations and anions; 2) quantity of plasma weak acids; 3) PaCO₂. Thus, metabolic acid-base disorders are always induced by a variation in SID (decreased in acidosis) or in weak acids (increased in acidosis), whereas respiratory disorders remains the consequence of a change in PaCO₂. These pathophysiological considerations are important to analyse complex acid-base imbalances in critically ill patients. For exemple, due to a decrease in weak acids, hypoalbuminemia increases SID which may counter-balance a decrease in pH and an elevated anion gap. Thus if using only traditionnal tools, hypoalbuminemia may mask a metabolic acidosis, because of a normal pH and a normal anion gap. In this case, the association of metabolic acidosis and alkalosis is only expressed by respectively a decreased SID and a decreased weak acids concentration. This concept allows to establish the relationship between hyperchloremic acidosis and infusion of solutes which contain large concentration of chloride such as NaCl 0.9%. Finally, the Stewart concept permits to understand that sodium bicarbonate as well as sodium lactate induces plasma alkalinization. In fact, sodium remains in plasma, whereas anion (lactate or bicarbonate) are metabolized leading to an increase in plasma SID.

Conclusion

Due to its simplicity, the traditionnal Henderson-Hasselbalch approach of acid-base disorders, remains commonly used. However, it gives an inadequate pathophysiological analysis which may conduct to a false diagnosis, especially with complex acid-base imbalances. Despite its apparent complexity, the Stewart concept permits to understand precisely the mechanisms of acid-base disorders. It has to become the most appropriate approach to analyse complex acid-base abnormalities.