Utilidad de la proteína C-reactiva para determinar la gravedad de infección por SARS-CoV-2 en Perú

Introducción: En los últimos años se han estudiado diversos biomarcadores para determinar los casos graves de COVID-19. La proteína C-reactiva (PCR) ha mostrado alta sensibilidad en la identificación de pacientes con enfermedad grave y utilidad comparable a la tomografía. Objetivo: Determinar la utilidad de la PCR para predecir gravedad de la infección por SARS-CoV-2 en pacientes hospitalizados en el Centro Médico Naval del Perú durante el periodo enero-septiembre del año 2021. Métodos: Se empleó un diseño de tipo cuantitativo, observacional, analítico, retrospectivo, y de tipo prueba diagnóstica. Se calculó un tamaño muestral de 503 pacientes, quienes fueron divididos en dos grupos de acuerdo a su gravedad. Resultados: Se determinó un punto de corte óptimo de 10,92 mg/L de los valores de PCR para el diagnóstico de enfermedad grave por COVID-19. Se calculó un área bajo la curva (AUC) de 0,762 y se obtuvieron valores de sensibilidad, especificidad, valores predictores positivo, negativo y precisión diagnóstica de 78,88%, 66,4%; 41,42%; 87,01%; y 67,27%, respectivamente. El normograma de Fagan mostró una probabilidad posprueba de 41%. En el modelo ajustado fueron significativas la PCR (ORa = 4,853; IC95% 2,987-7,886; p = 0,001), además de la ferritina (ORa = 1,001; IC 95%: 1,001-1,002; p = 0,001) e hipotiroidismo (OR ajustado = 4,899; IC 95%: 1,272-18,872; p = 0,021). Conclusiones: El presente estudio mostró la asociación entre la PCR y la gravedad de infección por SARS-CoV-2 en un modelo ajustado, mostrando su potencial utilidad y contribuyendo a determinar el punto de corte de la PCR en población peruana y su comparación a nivel internacional.

Background: Recently, many biomarkers have been studied to determine severe cases of COVID-19. C-reactive protein (CRP) has shown high sensitivity in identifying patients with severe disease and utility comparable to computed tomography. Aim: To determine the usefulness of CRP to predict the severity of SARS-CoV-2 infection in patients hospitalized at the Naval Medical Center of Peru during the period January-September in the year 2021. Methods: A quantitative, observational, analytical, retrospective, and diagnostic test type design was used. A sample size of 503 patients was calculated, which were divided into two groups according to their severity. Results: An optimal cut-off point of 10.92 mg/L for CRP levels was determined for the diagnosis of severe COVID-19. An area under the curve (AUC) of 0.762 was calculated and sensitivity, specificity, positive and negative predictive values and diagnostic accuracy values of 78.88%, 66.4%; 41.42%; 87.01%; and 67.27%; respectively. Fagan's normogram showed a post-test probability of 41%. In the adjusted model, CRP (aOR = 4.853; 95% CI 2.987-7.886; p = 0.001), ferritin (aOR = 1.001; 95% CI: 1.001-1.002; p = 0.001) and hypothyroidism (adjusted OR = 4899; 95% CI: 1272-18872; p = 0.021) showed significance. Conclusions: The present study showed an association between CRP and the severity of SARS-CoV-2 infection in an adjusted model, showing its potential utility and contributing to determine the cut-off point of CRP in the Peruvian population and its international comparison.

Inappropriate screening of obstructive coronary artery disease during pre-anesthesia assessment of candidates for non-cardiac surgery

Preoperative evaluation in elective surgeries has been associated with successful surgical treatment. However, there is no solid scientific evidence that screening for coronary artery disease (CAD) reduces surgical risk. The aims of this study were to describe the frequency of inappropriate investigation of obstructive CAD induced by pre-anesthetic assessment in individuals without cardiovascular symptoms (candidates for low- to intermediate-risk surgeries) and to evaluate predictors of this conduct. We performed a retrospective evaluation of medical records of anesthesiology services from patients undergoing pre-anesthesia assessment between May 2015 and May 2016, including those with functional capacity ≥4 metabolic equivalents without a diagnosis of heart disease. A total of 778 medical records (47±16 years of age, 62.6% female) were studied. A private hospital performed 50.1% of the surgeries and 60.4% were of intermediate risk. Only 2.7% (95%CI: 1.7-4.1%) were screened for CAD, and 91% of these requests were mediated by cardiology consultations performed during pre-anesthetic testing visits. Factors associated with screening for CAD were hypertension, diabetes, moderate systemic disease (ASA III), cardiac consultation, previous diagnosis of CAD, and admission to a private hospital. Independent predictors were private hospitals (OR: 3.9; 95%CI: 1.3-11.0), ASA III (OR: 5.3; 95%CI: 1.7-16.2), and hypertension (OR: 3.8; 95%CI: 1.5-9.8). The frequency of inappropriate requests for CAD screening in asymptomatic individuals without untreated systemic diseases was low in pre-anesthetic visits. Although infrequent, screening for CAD is more common in the private setting, in patients with poorer health status, and is usually prescribed during cardiology consultation.

Carcinoma de uraco, una neoplasia maligna poco frecuente / Urachal carcinoma, a rare malignant neoplasm / Carcinoma de úraco, uma neoplasia maligna pouco frequente

El carcinoma de uraco es una neoplasia maligna poco frecuente de predominio masculino entre la quinta a sexta década de la vida. Se localizan típicamente en la cúpula de la vejiga, con patrón histopatológico predominante de adenocarcinoma en el 90% de los casos. Tiene un curso indolente con manifestaciones clínicas en etapas tardías caracterizadas por hematuria, dolor abdominal, disuria, mucosuria, entre otros. El diagnóstico se basa en el hallazgo de la lesión por métodos endoscópicos e imagenológicos. Dado lo infrecuente de esta patología, se describe el caso de una paciente en su cuarta década de vida con infección de vías urinarias recurrente, en quien se documentó por medio de urografía por tomografía computarizada multicorte (UROTAC) de pólipo vesical resecado por resección transuretral (RTU) con reporte histológico de adenocarcinoma de tipo entérico.

Urachal carcinoma is a rare malignant neoplasm of male predominance between the fifth to sixth decade of life. It is typically located in the dome of the bladder, with a predominant histopathological pattern of adenocarcinoma in 90% of cases. It has an indolent course with clinical manifestations in late stages characterized by hematuria, abdominal pain, dysuria, mucosuria, among others. Diagnosis is based on the finding of the lesion by endoscopic and imaging techniques. Given the infrequent nature of this pathology, we describe the case of a female patient in her fourth decade of life with recurrent urinary tract infection, who was documented by MSCTU of bladder polyp resected by TURP with a histological report of enteric-type adenocarcinoma.

O carcinoma de úraco, é uma neoplasia maligna pouco frequente, predominantemente masculina que se manifesta entre a quinta e a sexta década de vida. Sua localização típica é a cúpula vesical e em 90% dos casos sua histologia corresponde a adenocarcinomas. Apresenta evolução indolente com manifestações clínicas nas etapas tardias caracterizadas por hematúria, dor abdominal, disúria, mucosúria, entre outros. O diagnóstico está baseado no achado da lesão por métodos endoscópicos e de imagens. Considerando a baixa frequência desta patologia, descreve-se o caso de uma paciente de sexo feminino em sua quarta década de vida com infecção recorrente das vias urinarias, na qual foi registrado, através de UROTAC, um pólipo vesical ressecado por RTU com laudo histológico de adenocarcinoma de tipo entérico.

Quality control of the slides by Kato-Katz method for the parasitological diagnosis of schistosomiasis infection by Schistosoma mansoni / Controle de qualidade das lâminas pelo método Kato-Katz para o diagnóstico parasitológico da esquistossomose mansônica

ABSTRACT Introduction: Kato-Katz is a laboratory method recommended by the Brazilian Ministry of Health (BMH) and the World Health Organization (WHO) as the gold standard for the diagnosis of human infection by Schistosoma mansoni. The method has great clinical and epidemiological relevance because it allows the parasite load quantification of the infected patient by calculating the number of eggs per gram (EPG) of feces. This classification may also be used to estimate the intensity of infection in the communities, to measure the impact of disease control measures, as well as to establish quality parameters for reading the slides. Objective: To describe the correct laboratory procedures for the parasitological diagnosis of S. mansoni infection by the Kato-Katz method based on the quality control protocol established by the Laboratory and Reference Service in Schistosomiasis/Centro de Pesquisa Aggeu Magalhães (CPqAM)/Fundação Oswaldo Cruz (Fiocruz)/BMH. Methods: We describe: 1) the technical steps for fecal sample preparation and reading the slides; 2) the technical limitations; 3) the standard operating procedure (SOP) to be adopted by laboratories; 4) the methodology for the internal and external quality control of the reading slides results; and 5) the tolerance limits accepted for such control. Conclusion: This study provides the laboratory which performs the diagnosis of schistosomiasis using the Kato-Katz method with parameters to implement a diagnostic service that can be evaluated internally and externally. The establishment of a quality protocol enables the comparison of data and the identification of failures in the operational procedure, which can be corrected by training personnel and taking actions for the problems identified.

RESUMO Introdução: O Kato-Katz é o método laboratorial adotado pelo Ministério da Saúde (MS) e pela Organização Mundial da Saúde (OMS) como padrão-ouro para o diagnóstico da infecção humana pelo Schistosoma mansoni, sendo uma ferramenta de relevância clínica e epidemiológica, visto que permite classificar a carga parasitária do indivíduo infectado pelo cálculo de ovos por grama de fezes (OPG). Essa classificação pode também ser utilizada para estimar a intensidade da infecção nas comunidades, mensurar o impacto de medidas de controle da doença bem como estabelecer parâmetros de qualidade para a leitura das lâminas. Objetivo: Descrever os procedimentos laboratoriais corretos para o diagnóstico parasitológico da infecção pelo S. mansoni pelo método Kato-Katz a partir do protocolo de controle de qualidade estabelecido pelo Laboratório e pelo Serviço de Referência em Esquistossomose/Centro de Pesquisa Aggeu Magalhães (CPqAM)/Fundação Oswaldo Cruz (Fiocruz)/MS. Método: São descritas: 1) as etapas técnicas para o preparo das amostras de fezes e a leitura das lâminas; 2) as limitações da técnica; 3) o procedimento operacional padrão (POP) a ser adotado pelos laboratórios; 4) a metodologia para o controle de qualidade interno e externo da leitura das lâminas; e 5) os limites de tolerância aceitos para tal controle. Conclusão: Este trabalho instrumentaliza os laboratórios que realizam o diagnóstico da esquistossomose pelo método Kato-Katz com parâmetros para implantar um serviço diagnóstico passível de ser avaliado interna e externamente. O estabelecimento de um protocolo de qualidade viabiliza a comparação de dados e a identificação de falhas no procedimento operacional, que poderão ser corrigidas por meio de capacitação de pessoal e tomada de medidas para os problemas identificados.

Evaluación de los test rápidos en el Hospital General de Bata, Guinea Ecuatorial / Assessment of rapid tests at Bata General Hospital, Equatorial Guinea

En los últimos años, los test rápidos han ganado importancia en el diagnóstico de la infección por VIH y otras infecciones de transmisión sexual. Aunque la sensibilidad de los nuevos test es comparable a la de las técnicas de Ensayo Inmunoenzimatico, la especificidad es algo menor. El propósito del trabajo ha sido examinar el rendimiento de las pruebas diagnósticas "rápidas" utilizadas en el Hospital Regional de Bata, Guinea Ecuatorial, para VIH, hepatitis B, hepatitis C y sífilis y verificar si realmente son las mejores para los diagnósticos de salud o enfermedad de los individuos. Se realizó un estudio con diseño observacional analítico, transversal de pruebas diagnósticas. Se determinó sensibilidad, especificidad, valor predictivo positivo, valor predictivo negativo, y razones de verosimilitud positiva y negativa. Se encontró que de los 356 especímenes estudiados, 193 (54,2%) tuvieron resultado positivo de todas las pruebas en conjunto. La probabilidad de que una prueba diagnostique correctamente a un individuo enfermo fue de 70,6%, con variaciones entre los diferentes diagnósticos., en general se diagnostican mejor los enfermos y no siempre los sanos se pueden descartar como verdaderos negativos. La confirmación del diagnóstico debe ser realizada en conjunto con otras técnicas, poco disponibles en este país.

In recent years rapid tests have been gaining importance in the diagnosis of HIV infection and other sexually transmitted infections. Although sensitivity of the newer tests is comparable to Immuno-enzymatic assay, the specificity is lower. The purpose of this study is to examine the performance of the rapid tests used in Bata Regional Hospital, Equatorial Guinea for HIV, B and C Hepatitis, and Syphilis assessing if they are really useful and the best for detecting diseases or health conditions of the individuals. An observational, analytic, and cross sectional study was performed including the diagnostic tests and sensitivity, specificity, positive and negative predictive values, so as the positive and negative probability ratios, with 95 % confidence intervals and calculated for every test respectively. Agreement was proved using Cohen Kappa test at 95 % of confidence level. From de 356 specimens, 193 (54.2 %) showed positive results for the entire set of tests. The probability of that, a rapid test correctly diagnose a person suffering from a disease was 70.6 %, showing variations among the different tests. The rapid test diagnoses better the sick person, but the healthy ones not always can be ruled out. The confirmation of the diagnosis must be carried out using other techniques, rarely available in this country.

Motives for requesting an electrocardiogram in primary health care / Motivos para requisitar um eletrocardiograma nos Cuidados de Saúde Primários

The management of requests for diagnostic exams presents its own inherent characteristics in primary health care and reflects the specific nature of the physician-patient relationship. The scope of the study was to identify the reasons for requesting an electrocardiogram (ECG) in primary health care. A cross-sectional study was conducted in an urban region in Portugal, establishing the motives to ask for an ECG consecutively over two years, starting on 01/03/2007 using data retrieved from structured forms filled out by the physician at the moment of requesting the exam. A total of 870 ECGs of 817 patients were included. Symptoms manifested during the patient visit justified 48.5% of the ECGs, and follow-up of cardiovascular risk factors motivated 25.2%. A global health examination accounted for 22.8% of the requests. Multivariate analysis showed that the presence of symptoms (p < 0.001), presence of any cardiovascular risk factor (p = 0.002), hypertension (p < 0.001), diabetes (p = 0.002), and urgency (p < 0.001) were the main factors associated with the requests. The requests for electrocardiograms are predominantly for clinical reasons as a result of patients symptoms. The integration of expectations and beliefs of the patients is present in the decision-making process.

Introdução: A gestão do pedido de testes de diagnóstico apresenta características próprias nos Cuidados de Saúde Primários em função da natureza específica da relação médico-doente. Objetivo: Identificar os motivos para requisitar um eletrocardiograma (ECG) na prática de Cuidados de Saúde Primários. Métodos: Realizou-se um estudo observacional transversal dos motivos para o pedido de um ECG numa região urbana de Portugal, utilizando um formulário preenchido pelo médico no momento da requisição, por um período de 2 anos desde 1/03/2007. Resultados: Foram incluídos 870 ECG de 817 doentes. A presença de sintomas na consulta justificou 48.5%, e o seguimento de fatores de risco cardiovasculares representou 25.2%. O exame global de saúde representou 22.8% dos pedidos. A análise multivariada mostrou que a existência de sintomas (p < 0.001), a presença de qualquer fator de risco cardiovascular (p = 0.002), a hipertensão arterial (p < 0.001), a diabetes mellitus (p = 0.002), e o pedido de urgência na execução (p < 0.001) foram os principais fatores associados aos pedidos. Conclusão: Os ECG são requisitados sobretudo em resposta a questões de natureza clínica perante sintomas que os doentes apresentam. A integração das expectativas e crenças dos doentes está presente no processo de decisão médica. .

Exámenes prequirúrgicos innecesarios y su costo en un hospital de Lambayeque / Unnecessary preoperative test and the cost in a hospital of Lambayeque

Introducción. En la práctica diaria antes de una cirugía suelen solicitarse exámenes preoperatorios sin ninguna utilidad. Sin embargo, las comorbilidades y el examen físico son los determinantes del desenlace en el acto quirúrgico. Objetivos. Determinar la frecuencia de exámenes prequirúrgicos innecesarios y su costo en pacientes con cirugía electiva del Hospital Regional Lambayeque de octubre de 2012 a julio de 2013. Material y método. Estudio descriptivo trasversal; muestreo aleatorio simple. Se compararon los exámenes solicitados con los recomendados por la guía de práctica clínica del National Institute for Health and Care Excellence (NICE) del 2003: Preoperative tests: The Use of routine preoperative tests for elective surgery. Resultados. Se revisaron 96 historias clínicas de pacientes con las siguientes cirugías: 62 colecistectomías (64,5 %), 16 hernioplastias inguinales (16,67 %), 12 facoemulsificaciones (12,5 %), 5 cirugías de fractura expuesta (5,21 %), y 1 hernioplastia abdominal (1,04 %); se hallaron 1 214 exámenes preoperatorios, 839 (69,1 %) fueron innecesarios. Los más frecuentes fueron: riesgo quirúrgico (innecesario en 92,2 %), tiempo de sangría (innecesario en 92 %) y grupo-factor (innecesario en 89,8 %). Los exámenes más costosos fueron el antígeno de superficie para hepatitis B (S/. 1 428) y riesgo quirúrgico (S/. 1 185). El costo total de los exámenes innecesarios fue S/. 8 858 (S/. 10 630 aproximadamente en un año). Conclusión. En el Hospital Regional Lambayeque de octubre de 2012 a julio de 2013, hubo una elevada frecuencia de exámenes prequirúrgicos innecesarios y un alto costo asociado a los mismos. Los más costosos fueron antígeno de superficie para hepatitis B y el riesgo quirúrgico.

Introduction. In daily practice, before surgery, preoperative tests often ordered without any utility. Comorbidities and physical examination, ancillary tests, are the determinants of outcome patient during surgery. Objectives. To determine the frequency of unnecessary preoperative test and cost in patients with elective surgery in the Hospital Regional Lambayeque from October 2012 to July 2013. Material and method. It’s a transversal descriptive study; simple random sampling. Requested tests were compared with those recommended by the clinical practice guideline of the National Institute for Health and Care Excellence (NICE) 2003: Preoperative tests: The use of preoperative routine tests for elective surgery. Results. The clinical histories of 96 patients were reviewed and show the next results: 62 cholecystectomies (64,5 %), inguinal hernia repair 16 (16,67 %), 12 phacoemulsification (12,5 %), 5 surgeries open fracture (5,21 %) and one abdominal hernia repair (1,04 %). Were found 1 214 preoperative test, 839 (69,1 %) were unnecessary, being the most common surgical risk (in 92,2 % of patients was unnecessary), bleeding time (92 %) and group and factor (unnecessary in 89,8 %). The test costliest was serological test for hepatitis B (S/. 1 428) and surgical risk (S/. 1 185). The total cost of unnecessary preoperative tests from October 2012 to July 2013 was S/. 8858 (S/. 10 630 about 1 year). Conclusion. In Hospital Regional Lambayeque from October 2012 to July 2013, there was a high frequency of unnecessary preoperative tests in elective surgeries and high costs associated with them. The tests that contributed more to the total cost were surface antigen for hepatitis B and surgical risk.

Radiografia de tórax de rotina em terapia intensiva: impacto na tomada de decisão / Routine chest radiography in intensive care: impact on decision-making

OBJETIVO: Verificar a prevalência de alterações clínicas nas radiografias de tórax e sua relação com a tomada de decisões em terapia intensiva. MÉTODOS: Coorte prospectiva, que envolveu pacientes internados não consecutivamente na unidade de terapia intensiva do Hospital Universitário Professor Polydoro Ernani de São Thiago, da Universidade Federal de Santa Catarina. Entre os meses de fevereiro e maio de 2011, foram avaliados diariamente os exames de imagem solicitados na unidade de terapia intensiva, sendo divididos conforme a razão de internação, o tipo de exame solicitado, o segmento anatômico estudado e a finalidade da solicitação. Posteriormente, segundo interpretação do médico intensivista, os exames foram divididos segundo alteração detectada e mudança em conduta médica. A análise estatística foi feita segundo o teste do qui-quadrado. RESULTADOS: Foram envolvidos 106 pacientes pela amostragem. Foram avaliados 447 exames de imagem, sendo 425 radiografias de tórax em incidência anteroposterior. Obteve-se média de 4,01 radiografias por paciente internado. Dentre as radiografias solicitadas, 79,3% foram interpretadas como normais. Das radiografias alteradas, 35,2% não suscitaram alteração em conduta. CONCLUSÃO: A maioria das radiografias solicitadas e realizadas na unidade de terapia intensiva não apresentou alterações clínicas estatisticamente relevantes, e as que demonstraram alterações não necessariamente propiciaram mudança em conduta.

OBJECTIVE: This study determined the prevalence of clinical abnormalities in chest radiographs and its relationship with decision-making in intensive care. METHODS: This prospective cohort study involved nonconsecutive patients who were admitted to the intensive care unit at the Hospital Universitário Professor Polydoro Ernani de São Thiago of the Universidade Federal de Santa Catarina. Imaging tests in the intensive care unit (ICU) were assessed daily between February and May 2011 and divided according to the reason for hospitalization, the type of test requested, anatomical segment under assessment and the purpose of the request. The imaging tests were interpreted by intensivists and subsequently divided according to the detected abnormalities and changes in medical care. The chi-squared test was used for statistical analysis. RESULTS: The study sample included 106 patients. A total of 447 imaging tests were assessed, 425 of which were anteroposterior chest radiographs. An average of 4.01 radiographs per patient was obtained. Among the requested radiographs, 79.3% were normal, and 35.2% of abnormal radiographs did not prompt changes in medical care. CONCLUSION: Most of the radiographs performed in the intensive care unit exhibited no statistically significant clinical alterations, and the radiographs that revealed abnormalities did not necessarily lead to changes in medical care.

Utilidad y costo-efectividad de los exámenes preoperatorios en cirugía otorrinolaringológica / Usefulness and cost-efectiveness of preoperative test in otolaryngological surgery

Introducción: La práctica de realizar exámenes preoperatorios, aunque muy difundida, carece de utilidad demostrada o de argumentos científicos que la sustenten. Más aún sus costos, pueden ser muy elevados. Objetivo: Determinar la utilidad y costo-efectividad de los exámenes preoperatorios en otorrinolaringología. Metodología: Estudio retrospectivo de una muestra de 160 fichas clínicas de pacientes ASA I (2 a 40 años, sanos) operados en el Hospital San Juan de Dios en el año 2006. Resultados: Ningún examen preoperatorio permitió prever una complicación perioperatoria. Dentro de los pacientes con exámenes normales se registraron 4 complicaciones. Se necesitaron 70 exámenes (con un costo de $703.500 pesos chilenos o USD $1,256) para detectar una patología. La detección de anormalidades, obligó al mayor uso de recursos mediante intervención clínica (repetición de exámenes o interconsultas), se asoció a un aumento del número de consultas médicas realizadas (4,4 vs 2,53 p =0,0002) y un aumento de los días de hospitalización (2,5 vs 1,77 p =0,025), sin reportar ningún beneficio. Cuarenta a cincuenta por ciento de las solicitudes de nasofaringolaringoscopías, audiometrías e impedanciometrías no mostraron justificación clínica. Se repitieron 20,1 por ciento de los exámenes preoperatorios, principalmente debido a su caducidad (45,1 por ciento). El costo oportunidad asociado a exámenes preoperatorios fue en promedio $28.608 por paciente, lo que anualmente equivale (como referente) al 27 por ciento> del costo de todas las amigdalectomías realizadas en este centro cada año. Discusión: El uso rutinario de exámenes preoperatorios parece ser una práctica costosa y sin utilidad.

Introduction: Although most surgeons order pre-operative laboratory tests, this practice is not based upon any evidence. Furthermore, they impose a potentially important monetary cost on the patient. Aim: To determine the usefulness and cost-effectiveness of preoperative tests in otolaryngology. Material and method: Retrospective study. A sample of 160 medical records of ASA I patients (2 to 40 years of age, without other known pathologies) that underwent surgery at the San Juan de Dios Hospital during 2006 was reviewed. Results: None of the tests ordered predicted any of the perisurgical complications found. Among patients with normal results, 4 had complications. It took 70 tests (at a cost of $ 703,500 Chilean pesos or U$D 1256) to detect a relevant pathology. Detection of abnormalities in test results forced significant more clinical interventions, and was associated with an increased number of medical consults (4.4 vs 2.53 p = 0.0002) and a prolonged hospital stay (2.5 vs 1.77 p = 0025). 20.1 percent of the test were repeated tests, mainly because they had passed the valid date(45.1 percent). The opportunity-cost associated with preoperative examinations averaged $ 28,608 per patient, which (as a reference) is equivalent annually to 27 percent of the cost of all tonsillectomies performed at this center each year. Conclusion: Routine pre-operative testing seems to be an expensive and useless practice.