Some open questions in pediatric regional anesthesia.

The aim of the paper is to review the literature concerning 4 unanswered or debatable questions concerning the practice of regional anesthesia in pediatric patients. The published material concerning the 4 selected topics is reviewed, namely importance of ropivacaine, preoperative coagulation screening tests, hemodynamic stability following neuraxial blocks and prevention/treatment of post-dural puncture headache. Of the 4 questions considered in this article, 3 can be reasonably answered in a consensual way. Ropivacaine has limitations for single shot procedures in infants but its advantages for continuous infusions are significant in comparison with those of bupivacaine. Preoperative coagulation screening tests are not necessary, even not useful in children when clinical history is not suggestive of coagulation disorders, with the notable exception of neonates and prematurely born infants less than 45 weeks of post-conceptual age. The long established hemodynamic stability following neuraxial blocks results from well equilibrated compensatory mechanisms which may not be functional in children with preoperative hemodynamic instability or anomalies of the regional blood flow distribution. Finally, even though the post-dural puncture headache is not frequent in children, its management still remains difficult and no definitive recommendation can be currently made in case of inadvertent dural puncture during an attempted epidural anesthesia in children.

Pharmacokinetics and analgesic effect of ropivacaine following ilioinguinal/iliohypogastric nerve block in children.

BACKGROUND: The aim was to investigate the efficacy, tolerance and pharmacokinetics of ropivavcaine when administered for ilioinguinal/iliohypogastric block in children. METHODS: We examined the pharmacokinetics and analgesic efficacy after ilioinguinal/iliohypogastric nerve block with 3 mg.kg-1 ropivacaine 5 mg.ml-1 in 22 children, aged 1-12 years, who were scheduled for inguinal surgery. Sixteen of 22 patients had a postoperative pain score < 4 (Objective Pain Scale). Nine children were given supplementary analgesics during the first six postoperative hours. RESULTS: The peak plasma concentration of total ropivacaine was 1.50 +/- 0.93 mg.l-1 (mean +/- SD) (range 0.64-4.77 mg.l-1) 15-64 min after the injection. The peak plasma concentration of free ropivacaine was 0.05 +/- 0.03 mg.l-1 (0.02-0.14 mg.l-1), which is well below the threshold for toxicity in adults. The terminal half-life was 2.0 +/- 0.7 h. No safety concerns or symptoms suggestive of systemic toxicity were observed. CONCLUSION: A dose of 3 mg.kg-1 of ropivacaine given as a single ilioinguinal/iliohypogastric nerve block in 1-12-year-old children provides satisfactory postoperative pain relief, and is well tolerated.

[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.

Adverse effects of regional anaesthesia in children.

True complications of regional block procedures pertain to the performance of the block technique and the local anaesthetic. Such complications include lesions caused by the device used, and many of these complications can be avoided by using specifically designed devices.Complications related to the local anaesthetic solution mainly consist of local and systemic complications. Local toxicity has mainly been reported in adults following spinal administration of 5% lidocaine (lignocaine), a drug that is not usually used in children. Systemic toxicity consists of CNS and cardiovascular complications, methaemoglobinaemia and allergic reactions. Systemic toxicity has special features in children, especially in those <1 year old. Infants have a much higher free serum concentration of local anaesthetics than older children and adults, and are more prone to the deleterious effects of local anaesthetics. Additionally, as regional blocks are usually performed under general anaesthesia in children, signs of CNS toxicity may be concealed. Because of their higher heart rate, newborns and infants are thought to be more prone to the phasic block produced by tertiary amine agents such as bupivacaine than are adults. Serum concentrations at which bupivacaine (and etidocaine) exert cardiac toxicity seem to be similar to those producing CNS toxicity. As there is an increased threshold for CNS toxicity in infants plus an increased (or equal) sensitivity to bupivacaine cardiotoxicity, cardiac signs may not be preceded by any sign of CNS toxicity. Cardiac complications include: (i) arrhythmias with high degree conduction block, major QRS widening, torsade de pointes, and ventricular tachycardia related to re-entry phenomena; and (ii) major vascular collapse favoured by a concomitant decrease in the myocardial contractile force. Other complications of regional block procedures result from poor selection of agent, and inadequate safety precautions and monitoring of the patient, especially during the postoperative period. There are 2 other groups of disorders often reported as complications of regional anaesthetics: (i) effects that were not anticipated by the anaesthetist because of a lack of knowledge of all the consequences of the technique used; and (ii) complications attributed to a concomitant regional block procedure but with no established, sometimes even improbable, causal link with the regional technique. The overall morbidity of regional anaesthesia in children is low. Sound selection of local anaesthetics, insertion routes and block procedures, together with appropriate and careful monitoring, should prevent any major undesirable effects and enable regional anaesthesia to be a well tolerated and effective tool to overcome pain associated with minimal morbidity.

[Pros or cons of accessory anesthetic circuits. I. Arguments for their use]. / Pour ou contre les circuits anesthésiques accessoires. I. Arguments pour leur utilisation.

In addition to the circle breathing system, which represents the main circuit of the anaesthetic machine, the use of an accessory breathing system (ABS), either a partial rebreathing system according to Mapleson's classification, or a system including a non-rebreathing valve, is appropriate for the anaesthetic management of many patients, depending on their physical status, age, indication and duration of surgery. The same safety rules, namely full checking procedure before use of the system and monitoring of inhaled gases and end-tidal CO2 must be applied as for the main circle system. Potential complications resulting from non compliance with these rules cannot be considered valuable reasons for denying the use of breathing systems that have safely been used for decades in millions of patients.

Epidemiology and morbidity of regional anesthesia in children: a one-year prospective survey of the French-Language Society of Pediatric Anesthesiologists.

We report the results of a prospective study on the practice of pediatric regional anesthesia by the French-Language Society of Pediatric Anesthesiologists (ADARPEF) during the period from May 1, 1993 to April 30, 1994. This study was designed to provide data concerning the epidemiology of regional anesthesia and its complications in a totally anonymous way. Data from 85,412 procedures, 61,003 pure general anesthetics and 24,409 anesthetics including a regional block, were prospectively collected. Central blocks (15,013), most of which were caudals, accounted for more than 60% of all regional anesthetics. Peripheral nerve blocks and local anesthesia techniques represented only 38% of regional blocks and Bier block was used only 69 times. Central and peripheral nerve blocks were performed in all pediatric age groups with some intergroup differences. Most blocks were performed under light general anesthesia (89%), confirming the fact that regional anesthetics are used as techniques of analgesia rather than anesthesia. Complications were rate (25 incidents involving 24 patients) and minor, and did not result in any sequelae or medicolegal action. Peripheral nerve blocks and local anesthesia techniques were generally safe. The overall complication rate of regional anesthesia was 0.9 per 1000, but because all complications occurred with central blocks, the complication rate of central blocks is in fact 1.5 per 1000 with significant variations in different age groups. This prospective study, based on a large and representative series of pediatric anesthetics, establishes the safety of regional anesthesia in children of all ages. It provides new insights on the practice of regional blocks and reveals that complications are rare and minor as they occur most often in the operating room and are readily managed by experienced anesthesiologists with resuscitative equipment at hand. The extremely low incidence of complications (zero in this study) after peripheral nerve blocks should encourage pediatric anesthesiologists to use them more often when they are appropriate, in the place of a central block.

[Diprivan and locoregional anesthesia in children over 3 years of age]. / Diprivan et anesthésie locorégionale chez l'enfant de plus trois ans.

Preparation for anaesthesia (at least 1 hour prior to surgery): Topical anaesthesia at venepuncture sites and at the site of the block. Possible premedication (rectal midazolam: 0.3 mg.kg-1). Anaesthetic induction: Insertion of venous cannula; i.v. injection of 3-4 mg.kg-1 propofol, mixed with 0.05% lidocaine; Control of child's ventilation conditions: tolerance of the face mask, Guedel airway, laryngeal mask; tracheal intubation would be easy if necessary and would not require muscle relaxants; In cases where the child is distressed or where venous access cannot be obtained, it is sometimes preferable to resort to inhalational induction with halogenated anaesthetics prior to venepuncture. Initial maintenance anaesthesia (performing the block): Propofol given as a continuous infusion of 13 mg.kg-1.h-1, after a bolus injection of 1.3 mg.kg-1 (alternative solution: maintaining anaesthesia using halogenated agents); Positioning of the patient and performing the block technique with relatively concentrated local anaesthetic solutions (to avoid differential blocks). Maintenance anaesthesia during the procedure: Propofol given as a continuous infusion in reduced doses: 2 to 5 mg.kg-1.h-1; Alternatively: halogenated anaesthesia at low concentrations (equivalent to 0.25 to 0.5 vol % of halothane). Recovery: Particularly rapid and pleasant recovery, with a minimum of side effects; In cases of day-case surgery, patient discharge has virtually never to be postponed.