Warning: XSLTProcessor::transformToXml() [xsltprocessor.transformtoxml]: I/O warning : failed to load external entity "file:////srv/scielo/www/bases/xml/ms/v22n3/1727-897X-ms-22-03-471.xml" in /srv-new/scielo/www/htdocs/class.XSLTransformerPHP5.php on line 36 Caracterización de apendicitis aguda en pacientes pediátricos. Cienfuegos, 2013-2018