Postoperative decrease in plasma sodium concentration after infusion of hypotonic intravenous solutions in neonatal surgery.

BACKGROUND: Hypotonic i.v. solutions can cause hyponatraemia in the context of paediatric surgery. However, this has not been demonstrated in neonatal surgery. The goal of this study was to define the relationship between infused perioperative free water and plasma sodium in neonates. METHODS: Newborns up to 7 days old undergoing abdominal or thoracic surgery were included in this prospective, observational study. Collected data included type and duration of surgery, calculated i.v. free water intake, and pre- and postoperative plasma sodium. Statistical analyses were performed using the Pearson correlation, Mann-Whitney test, and receiver operating characteristic analysis with a 1000 time bootstrap procedure. RESULTS: Thirty-four subjects were included. Postoperative hyponatraemia occurred in four subjects (11.9%). The difference between preoperative and postoperative plasma sodium measurements (ΔNaP) correlated with calculated free water intake during surgery (r=0.37, P=0.03), but not with preoperative free water intake. Calculated operative free water intake exceeding 6.5 ml kg(-1) h(-1) was associated with ΔNaP≥4 mM with a sensitivity and specificity [median (95% confidence interval)] of 0.7 (0.9-1) and 0.5 (0.3-0.7), respectively. CONCLUSIONS: Hypotonic solutions and i.v. free water intake of more than 6.5 ml kg(-1) h(-1) are associated with reductions in postoperative plasma sodium measurements ≥4 mM. In the context of neonatal surgery, close monitoring of plasma sodium is mandatory. Routine use of hypotonic i.v. solutions during neonatal surgery should be questioned as they are likely to reduce plasma sodium.

Renal transplantation in children: critical analysis of age related surgical complications.

To determine age-related risk factors of urological and vascular complications. We performed a retrospective analysis of the data of 202 renal transplantations in 193 children between 1989 and 2007 at a single institution. Out of 193 grafts (combined renal and liver grafts were excluded), we observed urological complications in 42 cases (21.7%) leading to graft loss in one case and vascular complications in 27 cases (13.9%) leading to graft loss in seven. The urological complications were VUR (n=25, 12.4%), ureteral stricture (n=10, 5%), anastomotic leak (n=4, 2%), ureteral necrosis (n=2, 1%), and incrustative pyelitis (n=1, 0.5%). Vascular complications were arterial stricture (n=14, 7.2%), arterial thrombosis (n=4, 2%), venous thrombosis (n=2, 1%), and others (n=7). Donors aged less than six yr were a risk factor of vascular complications leading to graft loss (p=0.0001), whereas patients with PUV had more urological complications (p=0.001). Overall patient and graft survival is 93.1% and 84% at five yr, respectively. Surgical complications remain a major cause of graft loss (12%) and morbidity in children's kidney transplantation (38.9%). Young age of donors is the major risk factor of early graft loss as a result of vascular complication. However, donor selection based on age is limited by the shortage of organs.

Pharmacological prevention of sevoflurane- and desflurane-related emergence agitation in children: a meta-analysis of published studies.

BACKGROUND: Emergence agitation (EA) in children is increased after sevoflurane anaesthesia. The efficacy of prophylactic treatment is controversial. The aim of this study was to provide a meta-analysis of the studies of the pharmacological prevention of EA in children. METHODS: A comprehensive literature search was conducted to identify clinical trials that focused on the prevention of EA in children anaesthetized with sevoflurane, desflurane, or both. The data from each trial were combined using the Mantel-Haenszel model to calculate the pooled odds ratio (OR) and 95% confidence interval. I(2) statistics were used to assess statistics heterogeneity and the funnel plot and the Begg-Mazumdar test to assess bias. RESULTS: Thirty-seven articles were found which included a total of 1695 patients in the intervention groups and 1477 in the control ones. Midazolam and 5HT(3) inhibitors were not found to have a protective effect against EA [OR=0.88 (0.44, 1.76); OR=0.39 (0.12, 1.31), respectively], whereas propofol [OR=0.21 (0.16, 0.28)], ketamine [OR=0.28 (0.13, 0.60)], alpha(2)-adrenoceptors [OR=0.23 (0.17, 0.33)], fentanyl [OR=0.31 (0.18, 0.56)], and peroperative analgesia [OR=0.15 (0.07, 0.34)] were all found to have a preventive effect. Subgroup analysis according to the peroperative analgesia given does not affect the results. CONCLUSIONS: This meta-analysis found that propofol, ketamine, fentanyl, and preoperative analgesia had a prophylactic effect in preventing EA. The analgesic properties of these drugs do not seem to have a role in this effect.

Premedication with clonidine is superior to benzodiazepines. A meta analysis of published studies.

BACKGROUND: Premedication is considered important in pediatric anesthesia. Benzodiazepines are the most commonly used premedication agents. Clonidine, an alpha2 adrenoceptor agonist, is gaining popularity among anesthesiologists. The goal of the present study was to perform a meta-analysis of studies comparing premedication with clonidine to Benzodiazepines. METHODS: A comprehensive literature search was conducted to identify clinical trials focusing on the comparison of clonidine and Benzodiazepines for premedication in children. Six reviewers independently assessed each study to meet the inclusion criteria and extracted data. Original data from each trial were combined to calculate the pooled odds ratio (OR) or the mean differences (MD), 95% confidence intervals [95% CI] and statistical heterogeneity were accessed. RESULTS: Ten publications fulfilling the inclusion criteria were found. Premedication with clonidine, in comparison with midazolam, exhibited a superior effect on sedation at induction (OR=0.49 [0.27, 0.89]), decreased the incidence of emergence agitation (OR=0.25 [0.11, 0.58]) and produced a more effective early post-operative analgesia (OR=0.33 [0.21, 0.58]). Compared with diazepam, clonidine was superior in preventing post-operative nausea and vomiting (PONV). DISCUSSION: Premedication with clonidine is superior to midazolam in producing sedation, decreasing post-operative pain and emergence agitation. However, the superiority of clonidine for PONV prevention remains unclear while other factors such as nausea prevention might interfere with this result.

Recent advances in the diagnosis of malignant hyperthermia susceptibility: how confident can we be of genetic testing?

Malignant hyperthermia (MH) is a condition that manifests in susceptible individuals only on exposure to certain anaesthetic agents. Although genetically heterogeneous, mutations in the RYR1 gene (19q13.1) are associated with the majority of reported MH cases. Guidelines for the genetic diagnosis for MH susceptibility have recently been introduced by the European MH Group (EMHG). These are designed to supplement the muscle biopsy testing procedure, the in vitro contracture test (IVCT), which has been the only means of patient screening for the last 30 years and which remains the method for definitive diagnosis in suspected probands. Discordance observed in some families between IVCT phenotype and susceptibility locus genotype could limit the confidence in genetic diagnosis. We have therefore assessed the prevalence of 15 RYR1 mutations currently used in the genetic diagnosis of MH in a sample of over 500 unrelated European MH susceptible individuals and have recorded the frequency of RYR1 genotype/IVCT phenotype discordance. RYR1 mutations were detected in up to approximately 30% of families investigated. Phenotype/genotype discordance in a single individual was observed in 10 out of 196 mutation-positive families. In five families a mutation-positive/IVCT-negative individual was observed, and in the other five families a mutation-negative/IVCT-positive individual was observed. These data represent the most comprehensive assessment of RYR1 mutation prevalence and genotype/phenotype correlation analysis and highlight the possible limitations of MH screening methods. The implications for genetic diagnosis are discussed.

Malignant hyperthermia and central core disease: analysis of two families with heterogeneous clinical expression.

We report two families both presenting with malignant hyperthermia susceptibility and "core" or "core-like" changes in the muscle tissue. Combined analysis of the malignant hyperthermia phenotype and the histochemical findings demonstrates the complexity of their association and highly suggests genetic heterogeneity of malignant hyperthermia and central core diseases.

Different effects of halothane on diaphragm and hindlimb muscle in rats.

The effects of halothane administration on diaphragm and tibialis anterior (TA) muscle were investigated in 30 anesthetized mechanically ventilated rats. Diaphragmatic strength was assessed in 17 rats by measuring the abdominal pressure (Pab) generated during supramaximal stimulation of the intramuscular phrenic nerve endings at frequencies of 0.5, 30, and 100 Hz. Halothane was administered during 30 min at a constant minimum alveolar concentration (MAC): 0.5, 1, and 1.5 MAC in three groups of five rats. For each MAC, Pab was significantly reduced for all frequencies of stimulation except at 100 Hz during 0.5 MAC halothane exposure. The effects of halothane (0.5, 1, and 1.5 MAC) on diaphragmatic neuromuscular transmission were assessed in five other rats by measuring the integrated electrical activity of the diaphragm (Edi) during electrical stimulation of the phrenic nerve. No change in Edi was observed during halothane exposure. In five other rats TA contraction was studied by measuring the strength of isometric contraction of the muscle during electrical stimulation of its nerve supply at different frequencies (0.5, 30, and 100 Hz). Muscle function was unchanged during administration of halothane in a cumulative fashion from 0.5 to 1.5 MAC. These results demonstrate that halothane does not affect hindlimb muscle function, whereas it had a direct negative inotropic effect on rat diaphragmatic muscle.

Thoracic pheochromocytoma revealed by ventricular tachycardia. Clinical case and review of the literature.

A case of thoracic extra-adrenal pheochromocytoma was observed in a 13-year-old girl. The initial clinical symptoms consisted of her being unwell after effort over a period of 3 years. The diagnosis was suggested after a recorded episode of paroxysmal ventricular tachycardia with concomitant hypertension, which reproduced the characteristic symptoms. Biochemical analysis confirmed hypersecretion of catecholamines and morphological examinations showed the presence of an isolated left median thoracic tumor. One year after surgical excision, the patient remained completely asymptomatic, in spite of resuming intense sporting activity. The diagnosis of ectopic pheochromocytoma should be considered as a possible etiology of cardiac rhythm disturbances or hypertension in children. Thorough biochemical and radiological examination including MIBG radioisotope scanning should be carried out systematically before surgical excision; pheochromocytomas in children are frequently extra-adrenal (30%), multifocal (50%) or associated with multiple endocrine neoplasms (NEM).

[Treatment of malignant hyperthermia crisis during anesthesia]. / Traitement de la crise d'hyperthermie maligne de l'anesthésie.

Malignant hyperthermia (MH), triggered by anaesthesia, is a rare and potentially fatal condition. It requires immediate and specific treatment. This review focuses on anticipation and organisation of treatment. Anticipation means that dantrolene should be available, that an anaesthetic machine should be kept free from all vapours of halogenated anaesthetics, and methods of cooling should be planned. A prompt availability in all operating theatres of dantrolene and the required machines is emphasized. Treatment of a MH episode includes stopping the administration of triggering agents, administering dantrolene, correcting metabolic and respiratory acidosis, and cooling. Different aspects of the cardiovascular pharmacology of dantrolene are discussed. Other drugs are seldom required if proper treatment is started soon enough after the crisis. Complications may arise during a fulminant episode. They are difficult to treat, and may lead to sequelae. A rational approach to the treatment of hyperkalaemia, circulatory and renal failure is discussed. After the crisis, dantrolene should be continued for a short time. Finally, the nonspecific signs which can give the earliest diagnosis possible of MH are discussed: an early diagnosis and early treatment with dantrolene are essential in reducing the mortality of malignant hyperthermia.

[Comparison of nalbuphine and pentazocine in the treatment of postoperative pain by self-administration]. / Comparaison de la nalbuphine et de la pentazocine dans le traitement de la douleur postopératoire par auto-administration.

The side-effects of two opioid agonist-antagonists, nalbuphine and pentazocine, were assessed when used for patient-controlled postoperative analgesia. Forty ASA I or II patients scheduled for upper abdominal surgery were randomly allocated to two equal groups. The anaesthetic technique was the same for all the patients: premedication with atropine and diazepam, induction with thiopentone and suxamethonium and maintenance with fentanyl, pancuronium, nitrous oxide and halothane. Patient-controlled computer assisted analgesia (On-Demand Analgesia Computer) was started in the recovery room at least 2 h after the last administration of fentanyl. The parameters used were: a routine hourly dose (the half of that received during the previous hour), with on demand delivery of nalbuphine (15 micrograms.kg-1) or pentazocine (45 micrograms.kg-1) aliquots respectively, with a refractory period between two demands of 4 min and a total hourly maximum dose of 16 mg and 48 mg respectively. The following parameters were measured before the start of self-administration, and every hour afterwards for 24 h: systolic (Pasys) and diastolic blood pressures, heart rate, pressure-rate product (PRP), respiratory rate, end-tidal CO2 and pain (by way of a three point scale). Analgesia was assessed on a four-point scale every 6 h. The total doses of nalbuphine and pentazocine administered were 94 +/- 43 mg and 251 +/- 150 mg respectively. The only parameters significantly different between the two groups were Pasys and PRP, being higher in the pentazocine group. There were no significant differences in the side-effects (drowsiness, nausea, vomiting, headache, amnesia, logorrhoea and urine retention). All patients in both groups were satisfied with this technique.(ABSTRACT TRUNCATED AT 250 WORDS)

[Pros and cons of adding an accessory breathing system to the main circle circuit. II. Arguments against their use]. / Pour ou contre les circuits anesthésiques accessoires. II. Arguments contre leur utilisation.

When compared to the circle system alternative breathing systems (ABS) are of no benefit. When the only indication of an ABS is emergency oxygen administration it should be connected to the O2 pipeline upstream from the flowmeter bank and the vaporiser. The use of an ABS for anaesthesia maintenance is no longer justified because of the difficulties in monitoring pressure, flow and concentrations of the gas mixture, the cost of gas and vapour administered at a high flow and the resulting pollution. The use of an ABS for very short anaesthetics is only acceptable if the administered gas mixture is monitored.

[Anesthesia for heart catheterization in children. Comparison of 3 techniques]. / Anesthésie pour cathétérisme cardiaque chez l'enfant: comparaison de trois techniques.

A study was carried out to compare the haemodynamic and respiratory effects, as well as the quality of recovery, of anaesthesia with ketamine, sodium gamma-hydroxybutyrate (GOH) and etomidate in children undergoing cardiac catheterization. Thirty children, mean age 48 +/- 35 months, ranked ASA 2 or 3 on account of congenital heart disease, were assigned to one of three groups (n = 10). They were given: in group E1, a 0.3 mg.kg-1 bolus of etomidate, followed by 0.1 mg.kg-1.min-1 for 10 minutes, and 0.026 mg.kg-1.min-1 thereafter; in group G2, a 50 mg.kg-1 bolus of GOH, and in group K3, a 4 mg.kg-1 bolus of ketamine followed by a continuous infusion of 0.083 mg.kg-1.min-1. The patients breathed spontaneously. Monitoring included heart rate, systolic, diastolic and mean blood pressure, pulse oximetry, and capnography. Femoral venous or arterial catheterization was performed after local anaesthesia (with no more than 2 mg.kg-1 of lidocaine). Measurements were performed before induction, and then 1, 10, 30 and 60 minutes afterwards. The quality of anaesthesia was assessed according to Steward's scale. The investigation lasted between 50 and 100 min in all three groups. There were no significant differences in haemodynamic and respiratory parameters during the investigation between the groups. Recovery was shorter and of better quality in group E1. On the opposite, 30 minutes after the end of the catheterization, all the patients in group K3 were stuporous, with 5 of them displaying involuntary movements. The patients of the other two groups reacted correctly to stimuli, but those in group G2 went back to sleep very rapidly. There were no complications.(ABSTRACT TRUNCATED AT 250 WORDS)

[A study of 11 ventilators for anesthesia: laboratory testing]. / Etude de 11 ventilateurs d'anesthésie: banc d'essai.

Eleven anaesthesia ventilators were instrumentally tested under various conditions. They included: Excel and Modulus II Plus (Ohmeda); 710 and Servo anaesthesia circle 985 (Siemens); Jollytronic (Soxil) and Elsa (Engström); SA2 and Cicero (Dräger); ABT 4,300 (Kontron); Monnal A and the prototype Alys (Taema). The test circuit comprised a two compartment model lung, a pneumotachograph, a pressure gauge in the "airway". The volume was calculated as the integral of flow rate. Each machine was calibrated by the firms' technicians. Before each test, the pneumotachograph was calibrated using a 11 air syringe and the pressure gauge with a 5 cm water column. Each machine ventilated the model lung for 30 min before starting the tests. There were five tests: 1) reliability of the machine's spirometer, 2) reliability of the ventilation rate, 3) reliability of pressure measurements, 4) effect of increasing fresh gas flow on spirometry, 5) effect of increasing downstream resistances. In usual simulated ventilatory conditions, all the machines accurately delivered the setted ventilation and spirometric measurements were with minimal error only. Several ventilators (SA2, Excel, 710, Elsa, ABT 4,300) did not succeed in maintaining their performances when compliance was strongly decreased or resistance of the test lung notably increased. Resistance in the circuit during simulated spontaneous ventilation was < 3.6 cmH2O.l-1.s-1. Increasing fresh gas flow raised the minute volume delivered in six ventilators. It is concluded that, during extreme ventilatory conditions, the inspired volume must be adjusted so as to maintain the inspired tidal volume. However, ventilators which increase inspiratory time in response to an increased mechanical load cannot be adjusted by this way.

[Anesthesia ventilators]. / Ventilateurs d'anesthésie.

OBJECTIVE: To review anaesthesia ventilators in current use in France by categories of ventilators. DATA SOURCES: References were obtained from computerized bibliographic search. (Medline), recent review articles, the library of the service and personal files. DATA SYNTHESIS: Anaesthesia ventilators can be allocated into three groups, depending on whether they readminister expired gases or not or allow both modalities. Contemporary ventilators provide either constant volume ventilation, or constant pressure ventilation, with or without a pressure plateau. Ventilators readministering expired gases after CO2 absorption, or closed circuit ventilators, are either of a double- or a single-circuit design. Double-circuit ventilators, or pneumatical bag or bellows squeezers, or bag-in-bottle or bellows-in-bottle (or box) ventilators, consist of a primary, or driving circuit (bottle or box) and a secondary or patient circuit (including a bag or a bellows or membrane chambers). Bellows-in-bottle ventilators have either standing bellows ascending at expiration, or hanging bellows, descending at expiration. Ascending bellows require a positive pressure of about 2 cmH2O throughout exhalation to allow the bellows to refill. The expired gas volume is a valuable indicator for leak and disconnection. Descending bellows generate a slight negative pressure during exhalation. In case of leak or disconnection they aspirate ambient air and cannot act therefore as an indicator for integrity of the circuit and the patient connection. Closed circuit ventilators with a single-circuit (patient circuit) include a insufflating device consisting either in a bellows or a cylinder with a piston, operated by a electric or pneumatic motor. As the hanging bellows of the double circuit ventilators, they generate a slight negative pressure during exhalation and aspirate ambient air in case of leak or disconnection. Ventilators not designed for the readministration of expired gases, or open circuit ventilators, are generally stand-alone mechanical ventilators modified to allow the administration of inhalational anaesthetic agents.

[Caffeine skinned fiber tension test: application to the diagnosis of susceptibility to malignant hyperthermia]. / Test à la caféine sur fibres pelées: application au diagnostic de la susceptibilité à l'hyperthermie maligne.

OBJECTIVE: To assess the reactivity of sarcoplasmic reticulum to caffeine, using the skinned muscle fibre tension test and to compare it with the reference in vitro contracture test in the diagnosis of malignant hyperthermia (HM) susceptibility. STUDY DESIGN: Laboratory investigation. MATERIAL: Muscle biopsies from 63 patients, including 29 classified as susceptible to MH (MHS) and 34 classified as non-susceptible (MHN) according to criteria of the European and the North American MH groups. METHOD: The reactivity to caffeine and halothane of skinned muscle fibres was compared, according to the type of fibres, with the data of the in vitro contracture test. The type of fibres (type I: oxidative, slow; type II: glycolytic, fast) were determined with strontium dose-response curves. RESULTS: The reactivity to caffeine was significantly lower in the MHS group, for both type I and type II skinned fibres. However, in comparison with the data of the in vitro contracture tests, using the ROC curve analysis, the best sensitivity-specificity compromise was 90%-71% and 74%-84% for type I and type II skinned fibres respectively. CONCLUSION: The skinned muscle fibre tension test cannot be used instead of the in vitro contracture test for the diagnostic of MHS. However, it may strengthen the data of the latter.

[Registration of peranesthetic cases of malignant hyperthermia in France. An update]. / Recensement des cas français d'hyperthermie maligne peranesthésique. Mise à jour.

Sixty-two suspected crises of anaesthetic malignant hyperthermia (MH) were collected between 1969 and 1988 by a retrospective inquiry which lasted four years. 33 patients (53%) died whilst 29 survived. 20 cases were confirmed to be MH, either directly or indirectly by way of muscle biopsy and halothane and caffeine contracture tests carried out according to the European MH group protocol by two laboratories. This group included 11 of the deaths, one family member of whom, at least, is sensitive (MHS), 7 MHS survivors and 2 survivors too young to undergo muscle biopsy but belonging to MHS families. 21 cases were highly suspect of MH: 15 of the deaths which occurred in a typical way, and 6 patients of three different families who have suffered from anaesthetic deaths which, clinically, suggested MH. Another 15 were possible MH cases, all survivors, including one case of Steinert's disease and a brother of a case of central core disease. 2 cases were still being debated, because they had equivocal results for the caffeine test (MHEc); the last 4 had negative muscle biopsies and were excluded. 33 close relatives of the MH patients were diagnosed as MHS. 44 others were found to be free from the genetic predisposition. It was strongly recommended to yet 11 others that they carry the MHS card because they were MHEc. The clinical, surgical and anesthetic pictures were always as described in the literature. The anaesthetic protocols included inhalational agents in 90% of cases; these were combined with suxamethonium in 55% of cases. Dantrolene was only used in 32% of cases, and then at inadequate doses and very often too late; this probably explains the large number of treatment failures. The number of severe forms of MH was also very high in this series (70%). The need to increase the means of prevention and screening for MH in France is stressed.

[Ventilators for anesthesia. Models available in France. Criteria for choice]. / Appareils d'anesthésie. Modèles disponibles en France. Critères de choix.

This update article discusses the criteria for the choice of an anaesthetic machine and provides a short analysis of the main components of the models commercialized in France in 1994. The following items are considered: the design of the machine, the fresh gas delivery system, the anaesthesia breathing system(s), the ventilator and the waste gas scavenging system, the monitors associated with the machine and other criteria such as facility of learning to run the machine and of its daily use, ease of "in-house" maintenance and quality of after-sales service, cost of the machine and of its use (driving gas, disposable equipment).

[Accessory anesthetic breathing systems: verification before use]. / Circuits anesthésiques accessoires: vérification avant utilisation.

Accessory or ancillary anaesthesia breathing systems can be defined as all those connected to the fresh gas outlet of the anaesthetic apparatus and used instead of the circle system associated with the ventilator, which is the main circuit. They include: the Mapleson systems, the systems with a nonrebreathing valve and the disposable systems with a carbon dioxide absorber. They can be a cause of major accidents when not checked before and monitored during use. This technical note describes techniques of preanaesthetic checking and monitoring during anaesthesia.

[Pharyngolaryngeal fibroscopy under general anesthesia in children. Technique and indications in sleep apnea and hypopnea]. / Pharyngo-laryngo-fibroscopie sous anesthésie générale chez l'enfant. Technique et indications dans les apnées/hypopnées du sommeil.

The frequency of obstructive sleep apnea syndromes in children is not negligible. The diagnosis is based on the parents' answers and on sleep recordings. Radiographs sometimes help defining the site of obstruction. However, except when there is a considerable, clinically obvious tonsillar hypertrophy (which is fortunately the most frequent case), the exact location of the obstruction may be difficult to assess. In fact, it is far less obvious and more often multiple than in adults, especially in cases of craniofacial malformation. A pharyngolaryngeal exploration technique with a flexible endoscope under general anesthesia (GA) has been developed in our department. With natural ventilation, when a GA is induced with halothane through a mask, muscular relaxation similar to that of natural sleep is obtained. A thin flexible endoscope is then inserted through the mask to observe the obstructive structures at the nasal, rhino/oropharyngeal or pharyngolaryngeal levels. During the past two years, 17 children were examined with this technique, which allows an extremely accurate diagnosis of the site of the obstruction. Four children had a craniofacial malformation. The examination evidenced 9 cases of adenotonsillar hypertrophy, 4 cases of dynamic laryngeal obstruction, 3 cases of basilingual obstruction and one case of circular collapse of the oropharynx. The evolution under treatment confirm the merits of this endoscopic examination technique for the etiological diagnosis of respiratory obstruction.