Utilidad de la prueba de reacción en cadena de la polimerasa preoperatoria durante la pandemia por SARS-CoV-2: el desafío de la incidencia cambiante / Utility of preoperative polymerase chain reaction testing during SARS-CoV-2 pandemic: The challenge of evolving incidence

Antecedentes y objetivo: La alta transmisibilidad de la infección por SARS CoV2 ha obligado a los sistemas de salud mundiales a arbitrar medidas para evitar su expansión. En España, el consenso alcanzado entre diferentes sociedades científicas recomienda la realización de la prueba de reacción en cadena de la polimerasa (PCR) como cribado preoperatorio de portadores asintomáticos. Nos propusimos evaluar el rendimiento de la PCR preoperatoria para detectar portadores asintomáticos. Material y métodos: Estudio observacional realizado en un hospital de tercer nivel. Comparamos los resultados de la prueba de PCR en tiempo real (RT-PCR) realizada en una cohorte de pacientes quirúrgicos de nuestra área asistencial con los resultados que hubiéramos esperado asumiendo los datos epidemiológicos publicados por las oficinas gubernamentales. Resultados: No registramos resultados positivos en las 2722 RT-PCR realizadas en nuestra área entre las semanas epidemiológicas 18 a 21, lo que implica una incidencia acumulada de nuevos casos tendente a cero. Asumiendo los datos epidemiológicos publicados, la proyección probabilística de individuos asintomáticos varió de 0.27 * 10e-4 (datos oficiales de nuevos casos diagnosticados por PCR) a 4.69 * 10e-4 si asumimos casos confirmados por IgG en nuestra provincia. Suponiendo una sensibilidad de RT-PCR del 95%, para obtener un resultado positivo, deberíamos realizar 38,461 y 2,028 pruebas respectivamente. Conclusiones: En escenarios de muy baja prevalencia y a pesar de su alta sensibilidad, la detección preoperatoria de portadores asintomáticos mediante de RT-PCR es de una efectividad cuestionable. Nuestros hallazgos evidencian la dificultad de establecer modelos predictivos fiables en el contexto de epidemias de evolución rápida, como la pandemia de SARS CoV2.(AU)

Introduction: Due to its high transmissibility, measures aimed at reducing the spread of SARS CoV2 have become mandatory. Different organizations have recommended performing polymerase chain reaction tests (PCR) as part of the preoperative screening of surgical patients. We aimed to determine the performance of PCR testing to detect asymptomatic carriers. Methods: Observational study carried out at a tertiary care center. We compared the results of preoperative real-time reverse-transcription-PCR test (RT-PCR) performed on a cohort of patients pending surgery with the results we would have expected assuming the epidemiological data released by government offices. Results: We registered no positives in the 2,722 preoperative RT-PCR tests performed in our health care area between epidemiological Weeks 18 to 21, meaning a cumulative incidence trending to zero. Assuming public epidemiological data, the probabilistic projection of potential asymptomatic individuals ranged from 0.27*10e -4 (according to official data of new cases diagnosed by PCR) to 4.69*10e -4 if we assumed cases confirmed by IgG test in our province. Assuming a RT-PCR sensitivity of 95%, to obtain a positive result we should perform 38,461 and 2,028 tests respectively. Conclusions: In scenarios of very low prevalence and despite high sensitivity scores, indiscriminate preoperative RT-PCR screening is of a questionable effectiveness for detecting asymptomatic carriers. Our findings evidence the difficulty of establishing reliable predictive models for the episodic and rapidly evolving incidence of infections such as has characterized the SARS CoV2 pandemic.(AU)

Utility of preoperative polymerase chain reaction testing during SARS-CoV-2 pandemic: The challenge of evolving incidence.

INTRODUCTION: Due to its high transmissibility, measures aimed at reducing the spread of SARS CoV2 have become mandatory. Different organizations have recommended performing polymerase chain reaction tests (PCR) as part of the preoperative screening of surgical patients. We aimed to determine the performance of PCR testing to detect asymptomatic carriers. METHODS: Observational study carried out at a tertiary care center. We compared the results of preoperative real-time reverse-transcription-PCR test (RT-PCR) performed on a cohort of patients pending surgery with the results we would have expected assuming the epidemiological data released by government offices. RESULTS: We registered no positives in the 2,722 preoperative RT-PCR tests performed in our health care area between epidemiological Weeks 18 to 21, meaning a cumulative incidence trending to zero. Assuming public epidemiological data, the probabilistic projection of potential asymptomatic individuals ranged from 0.27 × 10e-4 (according to official data of new cases diagnosed by PCR) to 4.69 × 10e-4 if we assumed cases confirmed by IgG test in our province. Assuming a RT-PCR sensitivity of 95%, to obtain a positive result we should perform 38,461 and 2,028 tests respectively. CONCLUSIONS: In scenarios of very low prevalence and despite high sensitivity scores, indiscriminate preoperative RT-PCR screening is of a questionable effectiveness for detecting asymptomatic carriers. Our findings evidence the difficulty of establishing reliable predictive models for the episodic and rapidly evolving incidence of infections such as has characterized the SARS CoV2 pandemic.

Utility of preoperative polymerase chain reaction testing during SARS-CoV-2 pandemic: The challenge of evolving incidence. / Utilidad de la prueba de reacción en cadena de la polimerasa preoperatoria durante la pandemia por SARS-CoV-2: el desafío de la incidencia cambiante.

INTRODUCTION: Due to its high transmissibility, measures aimed at reducing the spread of SARS CoV2 have become mandatory. Different organizations have recommended performing polymerase chain reaction tests (PCR) as part of the preoperative screening of surgical patients. We aimed to determine the performance of PCR testing to detect asymptomatic carriers. METHODS: Observational study carried out at a tertiary care center. We compared the results of preoperative real-time reverse-transcription-PCR test (RT-PCR) performed on a cohort of patients pending surgery with the results we would have expected assuming the epidemiological data released by government offices. RESULTS: We registered no positives in the 2,722 preoperative RT-PCR tests performed in our health care area between epidemiological Weeks 18 to 21, meaning a cumulative incidence trending to zero. Assuming public epidemiological data, the probabilistic projection of potential asymptomatic individuals ranged from 0.27*10e -4 (according to official data of new cases diagnosed by PCR) to 4.69*10e -4 if we assumed cases confirmed by IgG test in our province. Assuming a RT-PCR sensitivity of 95%, to obtain a positive result we should perform 38,461 and 2,028 tests respectively. CONCLUSIONS: In scenarios of very low prevalence and despite high sensitivity scores, indiscriminate preoperative RT-PCR screening is of a questionable effectiveness for detecting asymptomatic carriers. Our findings evidence the difficulty of establishing reliable predictive models for the episodic and rapidly evolving incidence of infections such as has characterized the SARS CoV2 pandemic.

Effects of treatments for drooling on caries risk in children and adolescents with cerebral palsy.

BACKGROUND: Neuromuscular impairment makes individuals with cerebral palsy (CP) more prone to drooling. Among the treatment options, there are procedures that interfere with saliva production. It is imperative to evaluate the effect of the different modalities since the reduction in salivary flow rate/production may exacerbate the risk of dental caries. MATERIAL AND METHODS: The aim of this study was to compare the effects of different treatments for drooling on caries risk and salivary parameters in children and adolescents with CP. STUDY DESIGN: A total of 142 children and adolescents with CP, aged 6 to 18 years, were assigned to groups based on the different treatments they had received for drooling: G1-anticholinergic drugs (n = 18), G2-botulinum toxin injection (n = 16), G3-salivary glands surgery (n = 16), G4-no treatment (n = 42), and G5-non-drooling subjects (n = 50). All participants were evaluated on the Simplified Oral Hygiene Index, and for the prevalence of dental caries (decayed, missing, and filled teeth index and white spot lesions). Unstimulated whole saliva was collected, and salivary flow rate and osmolality were measured. Chi-square, ANOVA and Poisson regression were calculated. Prevalence ratios and their respective 95 % confidence intervals were obtained. The significance level was fixed at 5%. RESULTS: No differences were found in the decayed, missing, and filled teeth index (p = 0.128) and Simplified Oral Hygiene Index (p = 0.674) among the different groups. G3 presented significantly higher percentages of WSL (p < 0.001), lower values of salivary flow rate (p < 0.001), and higher values of osmolality (p < 0.001). The white spot lesion prevalence ratio was higher only for G3 (Prevalence ratio = 14.36; IC 95% = 4.64-44.40; p < 0.001). CONCLUSIONS: Children and adolescents with CP who had received surgical treatment for drooling exhibited higher number of white spot lesions because of the reduced salivary flow rate and higher salivary osmolality.

Localization of neurons expressing substance P and neurokinin B gene transcripts in the human hypothalamus and basal forebrain.

In situ hybridization histochemistry was used to map the distribution of neurons expressing the substance P (SP) or neurokinin B (NKB) genes in the human hypothalamus and basal forebrain. Hypothalami from five adult males were frozen in isopentane at -30 degrees C and serially sectioned at 20 jm thickness. Every 20th section was hybridized with [35S]-labeled, 48-base synthetic cDNA probes that were complementary to either SP or NKB mRNAs. Slides were dipped into nuclear emulsion for visualization of mRNAs at the single-cell level. The location of labeled neurons (greater than x 5 background) was mapped by using an image-combining computer microscope system. A distinct and complementary distribution pattern of SP and NKB neurons was observed in the human hypothalamus and basal forebrain. NKB was the predominant tachykinin in the rostral hypothalamus, whereas SP mRNA predominated in the posterior hypothalamus. Numerous NKB neurons were identified in the magnocellular basal forebrain, the bed nucleus of stria terminalis, and the anterior hypothalamic area. Scattered NKB neurons were present in the infundibular and paraventricular nuclei, paraolfactory gyrus, posterior hypothalamic area, lateral division of the medial mammillary nucleus, and amygdala. Numerous neurons expressing SP mRNAs were identified in the premammillary, supramammillary, and medial mammillary nuclei; the posterior hypothalamic area; and the corpus striatum. Scattered SP neurons were also observed in the preoptic area; the infundibular, intermediate, dorsomedial, and ventromedial nuclei; the infundibular stalk; the amygdala; the bed nucleus of stria terminalis; and the paraolfactory gyrus. These studies provide the first description of the location of neurons that express tachykinin gene transcripts in the human hypothalamus.