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Print version ISSN 0034-7094
Rev. Bras. Anestesiol. vol.56 no.6 Campinas Nov./Dec. 2006
Neurological complications and damage of regional block in children under general anesthesia. A real problem or sporadic cases?*
Complicaciones y secuelas neurológicas de la anestesia regional realizada en niños bajo anestesia general. ¿Un problema real o casos esporádicos?
Verônica Vieira da Costa, TSAI; Mônica Rossi RodriguesI; Maria do Carmo Barretto de Carvalho FernandesII; Renato Ângelo Saraiva, TSAIII
do Hospital SARAH
IIEnfermeira do Hospital SARAH
IIICoordenador de Anestesiologia da Rede SARAH de Hospitais
METHODS: A prospective analysis of children who underwent orthopedic and reconstructive plastic surgeries under regional block associated with general anesthesia was undertaken. Anesthesia was induced and maintained by the intravenous or inhalational route. Regional block was done after general anesthesia and immediate complications, number of punctures, mean term complications, and the presence of neurological damage were evaluated.
RESULTS: Four hundred and forty-nine children, boys and girls, with a mean age of 6,7 years, were evaluated over a 13-month period. The majority of the patients underwent general anesthesia associated with epidural lumbar or caudal block. The prevalence of immediate complications was 3.6% and bleeding at the time of the puncture was the most frequent complication. The prevalence of average term complications was 1.1%, and hyposthesia was the most frequent complication. There was no long-term neurological damage.
CONCLUSIONS: The results of this study are similar to those found by other authors regarding the low prevalence of complications of regional block in children under general anesthesia, without the occurrence of permanent neurological damage. This can be attributed to the use of adequate material and the experience of the anesthesia team.
MÉTODO: En un análisis prospectivo se estudiaron niños sometidos a intervenciones quirúrgicas ortopédica y plástica reparadora bajo anestesia regional asociada a la anestesia general. La inducción y el mantenimiento de la anestesia fueron por vía venosa o por inhalación. Después de la anestesia general se realizaba anestesia regional y se evaluaba la existencia de complicaciones inmediatas, el número de punciones realizadas, complicaciones de medio plazo y la presencia de secuelas neurológicas.
RESULTADOS: En un período de 13 meses se estudiaron 499 niños de los dos sexos, con edad promedio entre 6 y 7 años. La mayoría de los pacientes se sometió a la anestesia general asociada a la peridural lumbar o caudal. La prevalencia de complicación inmediata fue de un 3,6%, siendo la más frecuente el sangramiento al momento de la punción. La prevalencia de complicaciones en medio plazo fue de un 1,1%, siendo la más frecuente la hipoestesia y no hubo secuela neurológica a largo plazo.
CONCLUSIONES: Los resultados del presente estudio están a tono con los de otros autores con relación a la baja prevalencia de complicaciones de la anestesia regional en niños bajo anestesia general, sin dejar secuelas neurológicas. Eso puede ser atribuido al uso de material adecuado y a la experiencia del equipo de anestesia.
Combining regional block with general anesthesia has benefits and limitations. Regional block reduces the dose of general anesthetics, produces excellent postoperative analgesia, and decreases the response to stress in children and teenagers 1. Despite the benefits, it has been questioned whether regional block in children, which is usually done under general anesthesia, is really safe 2. There is the potential risk of temporary or permanent neurological damage when the patient cannot complaint of paresthesia or pain while the blockade is being performed, which is a warning sign that the needle or catheter is close to the nerve fibers of the peripheral nerves and spinal cord 3,4.
In children, regional block before anesthetic induction is difficult to do, since this patient population does not allow it to be done when they are awake. At the department where this study was conducted, regional block is always done after general anesthesia in children because we believe that the efficacy of the regional block decreases the dose of the general anesthetic, making it easier to control postoperative pain in different types of surgical procedures.
The objective of this study was to evaluate the prevalence of neurological complications and injuries of regional block in children under general anesthesia.
After approval by the Ethics Committee of the hospital and verbal consent by the parents or guardians, a prospective study was done including every child, under 16 years old, undergoing orthopedic and reparatory plastic surgeries under regional block associated with general anesthesia from August 01, 2004 to August 31, 2005. In every case the anesthesiologist recorded the type of regional block associated with the general anesthesia, the used material, number of attempts, type, dose, volume, and concentration of local anesthetic, other drugs administered, and complications during the block, as well as those observed during the anesthetic-surgical procedure (immediate complications). Patients were evaluated 24 hours after the anesthesia (average term complications), and about 30 days after the surgery (long term complications) patients' charts were examined for reports of late injuries or complications. This research was done after the patient returned to the outpatient clinic. Descriptive or exploratory statistical analysis of the data was performed.
Four hundred and forty-nine patients, with a mean age of 6,7 ± 5.2 years (between 6 months and 16 years), were studied over a 13-month period. Forty-three percent of those (192) were girls and 57% (257) boys. Sixty-three per cent (284 patients) were classified as physical status ASA I, 36.3 % (163) ASA II, and 0.4% (2) ASA III (Table I).
Most patients (89%) underwent lumbar or caudal epidural block associated with general anesthesia, and in only 9% (42 patients) the continuous method was used (Figure 1).
Inhalational general anesthesia was used in 93.3% of the cases (419), balanced general anesthesia in 6.2% (28), and total intravenous anesthesia in 0.4% of the cases (2).
Bupivacaine with vasoconstrictor was the local anesthetic used in 80% of the cases (Table II).
In 81% of the patients (365) regional block was done with a single puncture, i.e., it was successful in the first attempt (Figure 2).
There were no complications during the epidural block and the surgical procedure in 95.1% of the patients (427). Six patients (1.3%) presented complications, such as block failure and technical difficulty for its administration. The remaining 16 cases (3.6%) presented immediate complications, of which bleeding (1.6%) and accidental puncture of the dura mater (0.9%) were the most frequent.
Twenty-four hours after the surgery (mean term complications), 1.1% of the patients (5) presented complications, such as hypoesthesia in 0.7% of the cases (3), urinary retention in 0.2% of the patients (1), and headache in 0.2% of the cases (1).
Most patients were discharged from the hospital 48 hours after the surgery, and no one returned to the hospital with complaints regarding the anesthetic-surgical procedure.
About 30 days after the surgery, patients returned to the outpatient clinic for follow-up. At that time, patients' charts were reviewed for reports of complications or damage (late complications). There were no cases of late neurological complication or damage.
Regional block in pediatrics is the accepted standard practice, being adopted in several departments, being increasingly indicated and used, especially in the last two decades 1.
The benefits for the patients during both the intraoperative and the postoperative periods are unquestionable, and include decreased dose of general anesthetics (intravenous and inhalational), decreased response to surgical stress, improved hemodynamic stability, fast awakening, excellent postoperative analgesia without the risk of respiratory depression, reduction in the need for postoperative controlled ventilation in certain surgeries, faster recovery of gastrointestinal function, and reduced length of stay in the ICU 5-7.
Several prospective and retrospective studies have demonstrated that the complications associated with regional block in children are rare, most of the time are not severe, and are easy to solve 8,9.
In general, anesthesiologists who work with children agree that regional blocks in those patients are safer and better tolerated when preceded by general anesthesia or sedation 2,4.
Reports of neurological deficits after complications of regional block in children under general anesthesia raised doubts and fueled the debate about what would be the best approach in this population 4,10,11.
The causes of neurological damage secondary to regional block include needle trauma, epidural hematoma, fluid collections, epidural abscess, and the administration of neurotoxic substances 12-14.
The main risk factors for neurological lesion are paresthesia during positioning of the needle or catheter, pain during the injection, preexisting neurological disease, and technical difficulties at the time of the block 3,4.
The lack of contradicting data and the clinical experience suggest that most blocks of small and large peripheral nerves and plexus, with the possible exception of the interscalene brachial plexus blockade, can be safely done under sedation or after superficial general anesthesia with spontaneous ventilation. Nerve stimulators help localizing peripheral nerves and increase the success rates, but there is no evidence that they reduce the potential for nervous lesion in the awaken or anesthetized patient 11.
Since epidural or simple caudal epidural blocks are administered below the spinal cone, they cannot cause direct damage to the spinal cord 11.
In the thoracic epidural block, the anatomical peculiarities of the thoracic vertebrae hinder the puncture and, therefore, the spinal cord is more prone to lesions.
The introduction of the epidural catheter at the thoracic and superior lumbar levels in anesthetized patients and under the effects of neuromuscular blockers is unquestionably more dangerous, since the spinal cord can be damaged and the presence of paresthesia cannot be detected 15.
In the case reported by Kasai et al. 14, a 9-year old child undergoing urgent appendectomy developed spinal cord edema from T10 to T12 after epidural block under general anesthesia. There was an accidental perforation of the dura mater in the first attempt to localize the epidural space. It was then decided to attempt a second time in the same space, which this time was uneventful, being administered 5 mL of 0.25% bupivacaine. The postoperative neurological exam demonstrated hypoesthesia in the lumbar segments, from L4 to S1, and in the left lower limb. Neurological symptoms reverted slowly and progressively.
Aldrete 15 reported the case of a 7-year old child scheduled for a Nissen fundoplication. Under general anesthesia and good neuromuscular blockade, an epidural catheter was placed in T8-T9. The epidural puncture was successful after multiple attempts. During the operative period, two injections of local anesthetic, 4 mL 1.5% lidocaine followed, after 45 minutes, by 5 mL 0.25% bupivacaine, resulted in blood hypotension. In the posthanestetic recovery unit, after another dose of 5 mL 0.25% bupivacaine through the catheter, the patient developed hypotension and temporary apnea. Sensitive and motor deficits were detected the following day. The patient developed syringomyelia from T5 to T10, dysesthesia from T6 to T10, decreased strength in the left lower limb, and bladder and intestinal dysfunction.
There are no prospective, randomized studies comparing the relative risks of regional block in conscious and anesthetized patients 16.
Tsui et al. 17 reported one case of spinal cord injury after thoracic epidural block in a conscious, adult patient.
In our department, regional blocks in children are done after induction of general anesthesia. This study demonstrated that there were no severe complications and there were no cases of neurological damage. This corroborates the results of other studies 8,9. Anesthesia was performed by anesthesiologists with more than five years experience and the material used was appropriate for each age Group. In only 3% of the cases more than three attempts were made during the regional block.
When the anesthesiologist decides for a regional block in a child under general anesthesia, who is not able to complaint about pain or paresthesia, other precautions should be taken before and during the block.
Careful preanesthetic assessment should look for information that indicate or exclude the possibility of preexisting neurological or vascular disease. For a safe regional block it is necessary to be careful during the procedure, use material that is adequate for the patient's age, pay attention to the needle and to the fact that any technical difficulty increases the risk of complications. Faced with the suspicion of technical difficulties, one should avoid several attempts, which are potentially traumatic, and look for alternatives. The presence of reflex muscle movements, greater resistance to the introduction of the needle, and, most importantly, any resistance to the injection, indicate the presence of contact with nervous structures. Eventual complications that might evolve to permanent injury should be identified and treated immediately. Residents should be adequately supervised because certain practical nuances might not be noticed in time 11.
Regional block in children is more comfortable for the patient, safer, and offer better technical conditions to the anesthesiologist. This study demonstrated the low prevalence of complications, mild complications, without neurological damage, and one might question if they would have happened whether the patient was anesthetized or conscious 17. Other studies presented similar results 8,9. Nevertheless, the indication of regional block under general anesthesia in children should be judicious, and the procedure should be done based on the conviction that the benefits are greater than the risks 11,18,19.
The authors wish to thank the statistician Érika Carvalho Pires Arci of the Hospital Sarah Brasília Centro Quality Control for her invaluable contribution in the processing of the data and statistical analysis.
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Dra. Verônica Vieira da Costa
SMHS Quadra 501 Conjunto A
70335-901 Brasília, DF
Submitted for publication
10 de março de 2006
Accepted for publication 08 de agosto de 2006
* Received from Hospital SARAH, Brasília, DF