Print version ISSN 0034-7094
Rev. Bras. Anestesiol. vol.51 no.4 Campinas 2001
Pneumocephalus after epidural anesthesia. Case report*
Pneumoencéfalo após anestesia peridural. Relato de caso
Pneumoencéfalo después de anestesia peridural. Relato de caso
Angélica de Fátima de Assunção Braga, TSA, M.D.I; Franklin Sarmento da Silva Braga, M.D.I; Glória Maria Braga Potério, TSA, M.D.I; Eugesse Cremonesi, TSA, M.D.II; Luiz Humberto David, M.D.III; Rogério Schimidtt, M.D.IV
IProf. (a) Dr. (a) do Departamento
de Anestesiologia da FCM/UNICAMP
IIAssessora Científica do Departamento de Anestesiologia da FCM/UNICAMP
IIIAnestesiologista do Centro de Atenção Integral a Saúde da Mulher (CAISM), UNICAMP
IVAnestesiologista do HC/UNICAMP
BACKGROUND AND OBJECTIVES: Epidural block
is the technique of choice to relieve labor pain. In spite of the advantages,
it is not free from complications, such as pneumocephalus. This report aimed
at presenting a case of iatrogenic pneumocephalus, diagnosed after epidural
block with accidental dural puncture.
CASE REPORT: A 16-year old patient, physical status ASA I, without anesthetic history was submitted to continuous epidural block for labor analgesia. After several puncture attempts at L3-L4 interspace, there was an accidental dural puncture. A new epidural puncture at L2-L3 was attempted without success. Another puncture in L3-L4 was attempted and after epidural space identification through the technique of loss of resistance to air, local anesthetics and fentanyl were injected followed by catheter introduction. Twenty minutes after blockade fetal distress was observed and cesarean section was indicated with an additional dose of local anesthetic administered through the catheter. Patient remained hemodynamically stable and conscious during surgery with a slow motor block recovery (14 h). There were two postoperative seizures with an interval of 12 h between them, which reverted spontaneously. Neurological evaluation was normal and CT scan revealed an image with air density compatible with pneumocephalus. Patient was discharged 3 days later without sequelae.
CONCLUSIONS: This case confirms the possibility of iatrogenic pneumocephalus during epidural block using the loss of resistance to air technique to identify the epidural space. In the presence of signs and symptoms of meningeal irritation, CT is the diagnostic tool recommended for the differential diagnosis of pneumocephalus and other causes.
Key words: ANESTHETIC TECHNIQUES, Regional: epidural; COMPLICATIONS, Neurologic: pneumocephalus; SURGERY, Obstetric
JUSTIFICATIVA E OBJETIVOS: O bloqueio
peridural constitui técnica utilizada para alívio da dor durante o
trabalho de parto. Apesar das vantagens, não é isenta de complicações,
como, por exemplo, o pneumoencéfalo. O objetivo deste relato é apresentar
um caso de pneumoencéfalo iatrogênico, diagnosticado após bloqueio
peridural, com punção acidental de duramáter.
RELATO DO CASO: Paciente de 16 anos, estado físico ASA I, sem antecedentes anestésicos, submetida a bloqueio peridural contínuo para analgesia de parto. Após várias tentativas de punções no espaço L3-L4, ocorreu punção acidental de duramáter. Optou-se por nova punção peridural em L2-L3, sem sucesso. Foi tentada outra punção em L3-L4, e após identificação do espaço peridural empregando-se a técnica da perda da resistência com ar, injetou-se o anestésico local e fentanil, seguido de passagem do cateter. Após 20 minutos da instalação do bloqueio, ocorreu sofrimento fetal, com indicação de cesariana, sendo administrada dose complementar de anestésico local pelo cateter. A paciente permaneceu hemodinamicamente estável e consciente durante a cirurgia, com lenta recuperação do bloqueio motor (14 h). No pós-operatório, apresentou dois episódios de crise convulsiva, com intervalo de 12 horas entre eles, que reverteram espontaneamente. A avaliação neurológica era normal e a tomografia computadorizada revelou imagem com densidade de ar compatível com pneumoencéfalo. A paciente teve alta três dias após, sem seqüelas.
CONCLUSÕES: O caso confirma a possibilidade de se causar pneumoencéfalo iatrogênico durante a realização de bloqueio peridural, empregando-se a técnica da perda de resistência ao ar para a identificação do espaço peridural. Na presença de sinais e sintomas de irritação meníngea, a tomografia computadorizada é o meio diagnóstico recomendado para o diagnóstico diferencial entre pneumoencéfalo e as demais causas.
Unitermos: CIRURGIA, Obstétrica; COMPLICAÇÕES, Neurológica: pneumoencéfalo; TÉCNICAS ANESTÉSICAS, Regional: peridural
JUSTIFICATIVA Y OBJETIVOS: El bloqueo
peridural constituye técnica utilizada para alivio del dolor durante el
trabajo de parto. A pesar de las ventajas, no es ilesa de complicaciones, como,
por ejemplo, el pneumoencéfalo. El objetivo de este relato es presentar
un caso de pneumoencéfalo iatrogénico, diagnosticado después
bloqueo peridural, con punción accidental de la duramadre.
RELATO DO CASO: Paciente de 16 años, estado físico ASA I, sin antecedentes anestésicos, sometida a bloqueo peridural continuo para analgesia de parto. Después de varias tentativas de punciones en el espacio L3-L4, ocurrió punción accidental de la duramadre. Se optó por nueva punción peridural en L2-L3, sin suceso. Fue tentada otra punción en L3-L4, y después identificación del espacio peridural usándose la técnica de la pérdida de resistencia con aire, se inyectó el anestésico local y fentanil, seguido de pasaje del catéter. Después de 20 minutos de la instalación del bloqueo, ocurrió sufrimiento fetal, con indicación de cesárea, siendo administrada dosis complementar de anestésico local por el catéter. La paciente permaneció hemodinámicamente estable y conciente durante la cirugía, con lenta recuperación del bloqueo motor (14 h). En el pós-operatorio, presentó dos episodios de crisis convulsiva, con intervalo de 12 horas entre ellos, que revertieron espontáneamente. La evaluación neurológica era normal y la topografía computadorizada reveló imagen con densidad de aire compatible con pneumoencéfalo. La paciente tuvo alta tres días después, sin consecuencias.
CONCLUSIONES: El caso confirma la posibilidad de causar pneumoencéfalo iatrogénico durante la realización del bloqueo peridural, utilizándose la técnica de la pierda de resistencia al aire para la identificación del espacio peridural. En presencia de señales y síntomas de irritación meníngea, la topografía computadorizada es el medio diagnóstico recomendado para el diagnóstico diferencial entre pneumoencéfalo y las demás causas.
Epidural block is a widely used technique for pain relief during labor. In spite of its numerous advantages it is not free from complications, such as hypotension, local anesthetics toxicity, total spinal anesthesia, accidental dural and blood vessels puncture, lumbar pain, subdural blockade and neurological complications 1-3. Since its description in 1885 4, several methods were proposed to identify the epidural space, the most popular of which being the loss of resistance to air technique described by Forestier & Sicard 5. Inadvertent air injection in the spinal space during such procedure although rare, should not be overlooked 6.
This report aimed at presenting a case of iatrogenic pneumocephalus diagnosed after epidural block with accidental dural puncture.
Female patient, 16 years old, 56 kg, 154 cm, gestation 1 to 0, with 40 weeks of gestational age, without anesthetic history, physical status ASA I submitted to continuous epidural block for labor analgesia. Monitoring was performed with cardioscope (DII), noninvasive blood pressure and pulse oximetry. Venoclysis was installed in an upper limb with an 18 G catheter for hydration and drug administration. Antisepsis and skin and ligaments infiltration with 1% lidocaine without vasoconstrictor were performed with the patient in the sitting position. After several puncture attempts at L3-L4 interspace with a disposable 16 G Tuohy needle there has been an accidental dural puncture confirmed by CSF leakage. We decided for a new epidural puncture at L2-L3 without success.
Another approach was attempted at L3-L4 and, after epidural space identification through the loss of resistance to air technique (with 3 to 4 ml of air in a10 ml glass syringe), 0.25% bupivacaine with epinephrine 1:200.000 (20 mg) associated to fentanyl (100 µg) were injected followed by a cephalic catheter insertion. In spite of all puncture difficulties, patient did not refer any discomfort. Twenty minutes after blockade there was a decrease in fetal heart rate with the indication for a Cesarean section and additional 0.5% bupivacaine (50 mg) with epinephrine 1:200.000 were administered through the catheter. Surgery went on without intercurrences and patient remained hemodynamically stable without respiratory or consciousness changes during the whole procedure. The female neonate weighed 2970 g with an Apgar score of 7 and 10 at the first and fifth minutes, respectively. At the end of the surgery, patient was sent to the PACU where she remained for 14 hours due to the slow motor block regression. Patient had two postoperative tonicoclonic seizures with a 12-hour interval between them, which reverted spontaneously. Neurological evaluation was normal. Cranial CT revealed a circular image with air density in the left frontal region (axial and coronal images), which was compatible with pneumo- cephalus (Figure 1 and Figure 2). Patient was discharged 3 days later without sequelae.
There are already in the literature reports of complications during air injection in the epidural space, including: nervous roots and spinal cord compression, retroperitoneal gas collection, subcutaneous emphysema, airway embolism, incomplete analgesia, paresthesia and pneumocephalus 7. Pneumocephalus is a relatively frequent complication in neurosurgery and/or neuroradiology 8,9, and may be also caused by trauma and infection 10.11. Although relatively rare, it may occur during epidural puncture.
Epidural space may be identified by the sudden loss of resistance to air or saline injection or by the detection of a negative pressure when the epidural space is reached 12,13. Syringe content - air or saline - for epidural space identification is being currently discussed. Fluids, which are not compressible, allow for the transition from the high resistance of extradural tissues to the low resistance of the epidural space to be immediately and convincingly identified, but when excessively used may dilute local anesthetics solution and result in an inadequate blockade 14. Air, for being compressible, makes more difficult the epidural space identification with the possibility of false-positive results 16. However, in experienced hands, glass syringes minimize such disadvantage and make the technique widely used by many centers 16. Another disadvantage of air as compared to saline was reported by Valentine et al. 17 and corresponds to a higher incidence of blockade extension failures represented by the increased number of non blocked segments, probably due to bubble formation and poor local anesthetics contact with nervous roots.
There is no consensus on the best technique and the one with less risk for complications should be preferred. There are no reports on saline-related complications7, while the loss of resistance to air technique has been charged with secondary effects, such as multiradicular syndromes, subcutaneous emphysema, gas embolism and pneumocephalus. Since the latter may evolve without symptoms it is not always diagnosed and may be more frequent than what has been reported 1,6,18-23.
Pneumocephalus may be clinically diagnosed by headache, seizures, consciousness level decrease, disorientation, dysarthria, nausea and vomiting 6,20,21,24. Symptoms intensity and duration depend on intracranial air distribution and are volume-dependent. Symptoms may revert spontaneously or be relieved by the supine position, hydration and drugs such as analgesics and caffeine. Inhalation of 100% oxygen is recommended for allowing the uptake of collected air nitrogen 25,26. Conversely, nitrous oxide inhalation increases gaseous volume thus worsening the situation and its use should be avoided when air is used to identify the epidural space 27,28.
In our case, patient did not refer headache. Such complaint, rare after epidural block with the loss of resistance to air technique, is frequent after dural puncture and pneumocephalus 7 and is attributed to intracranial meningeal irritation after air injection in the intrathecal or subdural space with a consequent cephalic dispersion 1. Aida et al. 29 have shown that the incidence of headache is significantly higher with air as compared to saline and that the latter should be preferred after accidental dural puncture 30.
Epidural space air pain is more intense than that resulting from its intrathecal injection. This is due to unique epidural space characteristics, such as low pressure and decreased capacitance, which allow the air to more rapidly spread in the cephalic direction even with the patient in the lateral position 31. Avellanal et al. 20 have described a pneumocephalus after spinal anesthesia without air injection, probably caused by the entrance of a small amount of air through the needle when the mandrel was removed.
Saberski et al. 7 have identified 13 pneumocephalus, 12 of which radiologically diagnosed as a technical complication of the loss of resistance to air technique, with air volumes varying from 2 to 20 ml.
We believe that, in our case, dural puncture during blockade attempt, the use of loss of resistance to air for epidural space identification and, as a consequence, a higher gas volume than what is normally used, allowed for the air entrance in the subdural and intrathecal space thus causing a pneumo- cephalus. Such complication could be avoided if in punctures following dural puncture we had used saline.
This case confirms the possibility of iatrogenic pneumo- cephalus during epidural block with the loss of resistance to air technique for epidural space identification. Faced to signs and symptoms of menyngeal irritation, CT is the diagnostic tool recommended for the differential diagnosis of pneumo- cephalus and other causes.
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Submitted for publication November 16, 2000 * Received
from Departamento de Anestesiologia da Faculdade de Ciências Médicas
da Universidade de Campinas (FCM/UNICAMP)
Accepted for publication December 28, 2000
Submitted for publication November 16, 2000
* Received from Departamento de Anestesiologia da Faculdade de Ciências Médicas da Universidade de Campinas (FCM/UNICAMP)