Importancia de la medición de la Viscosidad sanguínea: retos y limitaciones

La sangre es una mezcla de componentes que tiene su propia identidad. Una de las propiedades físicas que adquiere es su viscosidad, la cual es la resistencia que ofrece para desplazarse. A diferencia de sus componentes (como glucosa, hemoglobina, colesterol, etc.), la sangre no posee un nivel único de viscosidad, sino que esta es variable debido a diversos factores. Exponemos algunos principios físicos que nos permitirán entender mejor esta dinámica de la viscosidad sanguínea, y su posible aplicación en algunos fenómenos hemodinámicos, así como la complejidad de su medición en la práctica clínica habitual.

Blood is a mixture of components that has its own identity. One of the physical properties that it acquires is its viscosity, which is the resistance it offers to move. Unlike its components (such as glucose, hemoglobin, cholesterol, etc.), blood does not have a single level of viscosity, but it is variable due to various factors. We present some physical principles that will allow us to better understand these dynamics of blood viscosity, and its possible application in some hemodynamic phenomena, as well as the complexity of its measurement in routine clinical practice.

Blood Viscosity in COVID-19 Patients With Sudden Deafness.

BACKGROUND: Changes in blood viscoelastic properties have been proposed previosuly as etiopathogenesis for severe complications in COVID-19 and some cases of Sudden Deafness (SD). This is an attempt to verify if SD cases in patients admitted for SARS-Cov-2 infection can be correlated. PATIENTS AND METHODS: A prospective follow-up was carried out with COVID-19 patients, monitoring their blood viscosity (BV) at high shear rate (300 s-1) and inquiring them periodically for eventual hearing loss. This measurement was extended to cases bearing of SD in 2019 and 2020 without infection and a control group of healthy normoacoustic subjects. RESULTS: The normality range was 4,16 ± 0,62 cps. 330 cases admitted for COVID-19 were evaluated from February 24th, 2020 to March 24th, 2021, 85 of them attended in ICU. After anamnesis and Audiometric Tone Thresholds developed as soon as possible, 9 SD were detected, all belonging to ICU group. The mean BV was 4,38 ± 0,43 cps in the ward group, 4,53 ± 0,39 cps in the ICU patients without SD, and 4,85 ± 0,52 cps in the cases with SD, with statistically significant differences. Highest BV elevations in the SD cases were detected between days 6 and 10 of hospital admission. In 2019 four cases consulted with SD, and another two did it in 2020 without a diagnosis of COVID-19, with normal BV values. CONCLUSIONS: During SARS-Cov-2 infection, patients may show high BV and SS, although an inpatients control group and a larger sample volume are necessary to confirm the predisposition to hyperviscosity. The incidence of hearing damage is considerable if its possible appearance is taken into account, within the limitations of critical patients with COVID-19.

Viscosidad sanguínea en pacientes COVID-19 con sordera súbita / Blood viscosity in COVID-19 patients with sudden deafness

Antecedentes: La alteración en las propiedades viscoelásticas de la sangre ha sido anteriormente propuesta como etiopatogenia de complicaciones severas por COVID-19 y algunos casos de sordera súbita (SS). Pretendemos verificar si la aparición de casos de SS en pacientes ingresados por infección por SARS-CoV-2 puede correlacionarse de este modo. Pacientes y métodos: Estudio longitudinal prospectivo de pacientes ingresados en nuestro Centro por COVID-19, efectuando monitorización de la viscosidad sanguínea (VS) a alta velocidad de cizallamiento (300 seg-1) y un requerimiento periódico personal sobre hipoacusia. Esta determinación se extendió a casos atendidos por SS sin infección en 2019 y 2020 y un grupo control de sujetos sanos normoacúsicos. Resultados: El rango de normalidad se situó en 4,16±0,62 cps. Entre el 24 de febrero de 2020 y el 24 de marzo de 2021 se evaluaron 330 casos ingresados por COVID-19, 85 asistidos en la Unidad de Cuidados Intensivos (UCI). Fueron identificadas tras anamnesis y Audiometría Tonal Liminar (ATL) todo lo inmediata que el status clínico lo permitió hasta nueve casos con SS, todos pertenecientes al grupo de UCI. La VS media fue 4,38±0,43 cps en el grupo de sala, 4,53±0,39 cps en los pacientes en UCI sin SS, y 4,85±0,52 cps en los casos con SS, con diferencias estadísticamente significativas. Las mayores elevaciones de la VS en los casos con SS se detectaron entre los días seis y 10 del ingreso hospitalario. En 2019 consultaron cuatro casos y otros 2 en 2020 sin diagnóstico de COVID-19, con valores normales de VS. Conclusiones: Durante la infección por SARS-CoV-2 los pacientes pueden presentar elevación en la VS y SS, si bien se hacen necesarios un grupo control hospitalario y un volumen muestral mayor para confirmar la predisposición a la hiperviscosidad. La incidencia del daño auditivo resulta considerable si se tiene en cuenta su posible aparición en pacientes críticos con COVID-19. (AU)

Background: Changes in blood viscoelastic properties have been proposed previosuly as etiopathogenesis for severe complications in COVID-19 and some cases of Sudden Deafness (SD). This is an attempt to verify if SD cases in patients admitted for SARS-CoV-2 infection can be correlated. Patients and methods: A prospective follow-up was carried out with COVID-19 patients, monitoring their blood viscosity (BV) at high shear rate (300 sec-1) and inquiring them periodically for eventual hearing loss. This measurement was extended to cases bearing of SD in 2019 and 2020 without infection and a control group of healthy normoacoustic subjects. Results: The normality range was 4,16±0,62 cps. 330 cases admitted for COVID-19 were evaluated from February 24th, 2020 to March 24th, 2021, 85 of them attended in ICU. After anamnesis and Audiometric Tone Thresholds developed as soon as possible, 9 SD were detected, all belonging to ICU group. The mean BV was 4,38±0,43 cps in the ward group, 4,53±0,39 cps in the ICU patients without SD, and 4,85±0,52 cps in the cases with SD, with statistically significant differences. Highest BV elevations in the SD cases were detected between days 6 and 10 of hospital admission. In 2019 four cases consulted with SD, and another two did it in 2020 without a diagnosis of COVID-19, with normal BV values. Conclusions: During SARS-CoV-2 infection, patients may show high BV and SS, although an inpatients control group and a larger sample volume are necessary to confirm the predisposition to hyperviscosity. The incidence of hearing damage is considerable if its possible appearance is taken into account, within the limitations of critical patients with COVID-19. (AU)

Factores bioquímicos y nutricionales asociados a la viscosidad sanguínea en adultos de la sierra urbana (Imbabura), Ecuador / Biochemical and nutritional factors associated with blood viscosity in adults living in a mountain chain, (Imbabura), Ecuador

La asociación de la viscosidad sanguínea (VS) con la hipertensión y la diabetes mellitus 2, indica que debe ser considerada sobre todo en poblaciones que viven en la sierra donde el hematocrito y la hemoglobina son más elevados. Se evaluó la asociación de la VS con factores de riesgo cardiovascular y de síndrome metabólico (SM) en una población de 237 adultos (20-60 años) de la sierra urbana ecuatoriana. Se calculó el índice de masa corporal (IMC), porcentaje de grasa y agua corporal, se midieron la circunferencia de la cintura (CC) y la presión arterial. Se realizaron determinaciones de parámetros bioquímicos, hematológicos y de VS (mediante fórmula validada). El 14,76% de la población presentó hiperviscosidad (HV). El 42,8% de las personas con HV presentó SM contra 33% en el grupo con normoviscosidad (NV). El ácido úrico (AU) se observó más elevado en los grupos HV y NV con SM. Se encontró una correlación lineal simple de las concentraciones de glucosa (GLU) y de triglicéridos (TRI) con la VS en el grupo HV sin SM. El análisis de regresión lineal múltiple indicó que la GLU, el AU y la presión sistólica son variables que influyen independientemente con el incremento de la VS en el grupo HV sin SM. Las variables GLU y % de agua influyen en el incremento de la VS en el grupo NV sin SM. El incremento de las concentraciones de glucosa y de ácido úrico son los dos factores que mayormente influyen en la VS en esta población.

The association of blood viscosity (BV) with hypertension and diabetes mellitus type 2 indicates that it should be considered, especially in populations living in mountain chains where the hemoglobin and hematocrit values are higher. In fact, this work analyzed the association of BV with nutritional and biochemical risk factors in the development of cardio metabolic diseases in healthy adults (20-60 years old; 46.39% female and 53.61% male) living in the urban Ecuadorian sierra. The body mass index (BMI) was calculated. The body fat percentage, body water percentage, waist circumference (WC) and blood pressure were measured. Determinations of biochemical and hematological parameters were performed using established methodologies and a validated formula was used to determine the BV. Hyperviscosity (HV) was present in 14.76% of the population: 10.46% men, 4.3% women. In this group, 42.8% showed metabolic syndrome (MS) against 33% in the normoviscosity group (NV). Uric acid (UA) was observed statistically higher in HV and NV with MS groups. A simple positive linear correlation was found between glucose (GLU) and triglycerides (TRI) concentrations and BV in HV without MS group. The multiple linear regression analysis indicated that GLU, UA and systolic pressure influence to increase BV in the HV without MS group. Glucose concentration and percentage of water, independently influence the BV in the NV without MS group. The increase in GLU and UA concentrations are the most influencing factors on BV in this population.