Infrared thermography for normal endothelial function screening.

BACKGROUND: Endothelial dysfunction (ED) suspicion will allow to prevent accelerated atherosclerosis and premature death. OBJECTIVE: To establish the usefulness of thermography for endothelial function screening in adults with cardiovascular risk factors. MATERIAL AND METHODS: Cross-sectional, analytical diagnostic test. A brachial arterial diameter (BAD) increase < 11% at one-minute post-ischemia meant probable ED and was confirmed if BAD was ≥ 11% post-sublingual nitroglycerin. Thermographic photographs of the palmar region were obtained at one minute. Descriptive statistics, ROC curve, Mann-Whitney's U-test, chi-square test, or Fisher's exact test were used. RESULTS: Thirty-eight subjects with a median age of 50 years, and with 624 thermographic measurements were included. Nine had ED (flow-mediated vasodilation [FMV]: 2.5%). The best cutoff point for normal endothelial function in subjects with cardiovascular risk factors was ≥ 36 °C at one minute of ischemia, with 85% sensitivity, 70% specificity, positive and negative predictive values of 78 and 77%, area under the curve of 0.796, LR+ 2.82, LR- 0.22. CONCLUSION: An infrared thermography-measured temperature in the palmar region greater than or equal to 36 °C after one minute of ischemia is practical, non-invasive, and inexpensive for normal endothelial function screening in adults with cardiovascular risk factors.

ANTECEDENTES: La sospecha de disfunción endotelial (DE) permitirá prevenir la aterosclerosis acelerada y la muerte prematura. OBJETIVO: Establecer la utilidad de la termografía en el cribado de la función endotelial en adultos con factores de riesgo cardiovascular. MATERIAL Y MÉTODOS: Estudio transversal analítico de prueba diagnóstica. El incremento del diámetro de la arteria braquial < 11 % a un minuto posisquemia significó probable DE, confirmada si el diámetro fue ≥ 11 % posnitroglicerina sublingual. Se obtuvieron fotografías termográficas al minuto de la región palmar. Se aplicó estadística descriptiva, curva ROC, pruebas U de Mann-Whitney, chi cuadrada o exacta de Fisher. RESULTADOS: Se incluyeron 38 sujetos, mediana de edad de 50 años, con 624 mediciones termográficas; nueve presentaron DE (vasodilatación mediada por flujo de 2.5 %). El mejor punto de corte para la función endotelial normal en sujetos con factores de riesgo cardiovascular fue ≥ 36 °C al minuto de isquemia, con sensibilidad de 85%, especificidad de 70%, valores predictivos positivo y negativo de 78 y 77%, área bajo la curva de 0.796, razón de verisimilitud positiva de 2.82 y razón de verisimilitud negativa de 0.22. CONCLUSIÓN: La medición de la temperatura en la región palmar mediante termografía infrarroja ≥ 36 °C tras un minuto de isquemia es práctica, no invasiva y económica para el cribado de la función endotelial normal en adultos con factores de riesgo cardiovascular.

Termografía infrarroja en la detección de la función endotelial normal / Infrared thermography for normal endothelial function screening

Resumen Antecedentes: La sospecha de disfunción endotelial (DE) permitirá prevenir la aterosclerosis acelerada y la muerte prematura. Objetivo: Establecer la utilidad de la termografía en el cribado de la función endotelial en adultos con factores de riesgo cardiovascular. Material y métodos: Estudio transversal analítico de prueba diagnóstica. El incremento del diámetro de la arteria braquial < 11 % a un minuto posisquemia significó probable DE, confirmada si el diámetro fue ≥ 11 % posnitroglicerina sublingual. Se obtuvieron fotografías termográficas al minuto de la región palmar. Se aplicó estadística descriptiva, curva ROC, pruebas U de Mann-Whitney, chi cuadrada o exacta de Fisher. Resultados: Se incluyeron 38 sujetos, mediana de edad de 50 años, con 624 mediciones termográficas; nueve presentaron DE (vasodilatación mediada por flujo de 2.5 %). El mejor punto de corte para la función endotelial normal en sujetos con factores de riesgo cardiovascular fue ≥ 36 °C al minuto de isquemia, con sensibilidad de 85%, especificidad de 70%, valores predictivos positivo y negativo de 78 y 77%, área bajo la curva de 0.796, razón de verisimilitud positiva de 2.82 y razón de verisimilitud negativa de 0.22. Conclusión: La medición de la temperatura en la región palmar mediante termografía infrarroja ≥ 36 °C tras un minuto de isquemia es práctica, no invasiva y económica para el cribado de la función endotelial normal en adultos con factores de riesgo cardiovascular.

Abstract Background: Endothelial dysfunction (ED) suspicion will allow to prevent accelerated atherosclerosis and premature death. Objective: To establish the usefulness of thermography for endothelial function screening in adults with cardiovascular risk factors. Material and methods: Cross-sectional, analytical diagnostic test. A brachial arterial diameter (BAD) increase <11 % at one-minute post-ischemia meant probable ED and was confirmed if BAD was ≥ 11 % post-sublingual nitroglycerin. Thermographic photographs of the palmar region were obtained at one minute. Descriptive statistics, ROC curve, Mann-Whitney’s U-test, chi-square test, or Fisher’s exact test were used. Results: Thirty-eight subjects with a median age of 50 years, and with 624 thermographic measurements were included. Nine had ED (flow-mediated vasodilation (FMV): 2.5 %. The best cutoff point for normal endothelial function in subjects with cardiovascular risk factors was ≥ 36 °C at one minute of ischemia, with 85 % sensitivity, 70 % specificity, positive and negative predictive values of 78 and 77 %, area under the curve of 0.796, LR+ 2.82, LR- 0.22. Conclusions: An infrared thermography-measured temperature in the palmar region greater than or equal to 36 °C after one minute of ischemia is practical, non-invasive, and inexpensive for normal endothelial function screening in adults with cardiovascular risk factors.

Early Detection of Vascular Obstruction in Microvascular Flaps Using a Thermographic Camera.

BACKGROUND: In microsurgical reconstruction, vascular obstruction occurs in approximately 20% of patients. Close monitoring is central to their care. Clinical/Doppler detection of vascular obstruction could be enhanced by thermography. METHODS: A diagnostic test design included consecutive cases of hospitalized patients, ≥18 years old, who underwent surgery with free flaps. Two researchers separately evaluated patients with clinical/Doppler methods and thermographic camera hourly for 24 hours, every 2 hours for the next 24 hours, and then every 3 hours until discharge. The gold standard was visualization of thrombus or vascular obstruction during surgical reintervention. Sensitivity, specificity, positive/negative predictive value (PPV/NPV), and a delta temperature receiver operating characteristic (ROC) curve were calculated. RESULTS: A total of 2,364 tests were performed with a thermographic camera in 40 patients (31 females, 9 males) aged 50.12 ± 9.7 years. There were 28 deep inferior epigastric perforator, 5 anterolateral thigh, 3 radial, 2 scapular, 1 fibular, and 1 anteromedial thigh flaps included. Six (15%) had postoperative vascular obstruction (5 venous and 1 arterial). One flap developed partial necrosis and one total necrosis (overall survival 97.5%). ROC curve (area 0.97) showed the best results at ≥ 1.8°C of difference to the surrounding skin. Considering two consecutive positive evaluations, the sensitivity was 93%, specificity 96%, PPV 57%, and NPV 99%. The thermal imaging camera allows to identify the obstruction between 2 and 12 hours before the clinical method. CONCLUSION: Utilizing a thermographic camera can reduce detection time of vascular obstruction by several hours in microvascular free flaps that include the cutaneous island. This method proves useful for early diagnosis of postoperative vascular obstruction.

[Perioperative management protocol of patients undergoing microsurgical flaps in main healthcare centers]. / Protocolo de manejo perioperatorio de procedimientos microquirúrgicos en hospitales de concentración.

Microsurgery is one of the most fertile and innovative area in reconstructive surgery. Today it is considered an indispensable technique in plastic surgery with flaps survival rates over 95% in main healthcare centers. The factors involved in achieving these results are: the improvement of the surgical technique, adequate patient selection and careful perioperative care. Perioperative care starts at the initial assessment of the patient where it's very important to consider the indications and contraindications of these procedures. We use this type of reconstruction when we face complex and extensive defects, they are mostly of the times, difficult or impossible to reconstruct with other techniques. Antibiotic prophylaxis should begin an hour before initial incision. Free flap procedures are classified as maximum risk for venous thromboembolism so it's essential to indicate an appropriate prophylaxis. Normothermia, proper fluid management and judicious use of transfusions and vasopressor are a fundamental part of intraoperative care. Postoperative monitoring of these flaps is essential for early detection of vascular thrombosis in order to save the transferred tissue.

La microcirugía es una de las áreas más fértiles e innovadoras con las que cuenta la cirugía reconstructiva; los factores que han intervenido para lograr estos resultados son: el perfeccionamiento de la técnica quirúrgica, la adecuada selección de los pacientes y los minuciosos cuidados perioperatorios a los que son sometidos estos pacientes. Los cuidados perioperatorios comienzan desde la valoración inicial del paciente donde es muy importante considerar las indicaciones y contraindicaciones de estos procedimientos. Recurrimos a este tipo de reconstrucción cuando nos enfrentamos a defectos complejos y/o extensos, que son difíciles o imposibles de reconstruir con otras técnicas. La profilaxis antibiótica debe comenzar una hora antes de la incisión inicial. Los colgajos libres se clasifican como procedimientos con riesgo máximo para tromboembolismo venoso, por lo que es indispensable indicar una adecuada profilaxis. La normotermia, un adecuado manejo de líquidos, así como un uso juicioso de las transfusiones y de vasopresores son parte fundamental de los cuidados transoperatorios. La monitorización posquirúrgica de estos colgajos es fundamental para detectar tempranamente trombosis vascular y poder salvar el tejido transferido.