Time-weighted vs. conventional quantification of 24-h average systolic and diastolic ambulatory blood pressures.

BACKGROUND: Conventional calculation of mean 24-h ambulatory blood pressure (BP), SBP and DBP based on the average of all BP readings disregards the fact that a larger number of measurements is usually scheduled during the daytime than at night, an imbalance possibly leading to an overestimation of 24-h average BP. The aim of our study was to quantify this possible bias and to explore its determinants. METHODS: Four hundred and fifty untreated individuals were subdivided into three groups (150 individuals each) with three different ambulatory blood pressure measurement schedules for day/night: group I, four (day)/two (night) readings/h; group II, four (day)/three (night) readings/h; and group III, with BP readings every 30 min throughout 24 h. Hourly and 24-h averages were computed. The conventional 24-h averages of all SBP and DBP values were compared with the averages of hourly SBP and DBP mean values (time-weighted quantification). The difference between 24-h conventional and 24-h time-weighted BP was computed in each group and related to the degree of nocturnal BP dip and to the ratio between the number of readings of day and night. RESULT: In the three groups, 24-h conventional and 24-h time-weighted BP values were highly correlated (r > 0.99), 24-h conventional SBP and DBP being significantly higher (P < 0.01) than the corresponding 24-h time-weighted values in groups I and II but not in group III (Bland-Altman analysis). The bias magnitude was related to the day/night ratio in number of readings and to nocturnal BP dip in groups I and II (P < 0.01) but not in group III. CONCLUSION: The higher number of readings/h during daytime leads to an overestimation of conventional 24-h average BP, particularly in individuals with preserved nocturnal BP dipping. This can be avoided either by scheduling the same number of readings/h throughout 24 h or by performing a time-weighted quantification of 24-h BP. The clinical implications of these different approaches deserve further investigation.

Embolismo por polimetil-metacrilato posterior a inyección subcutánea en región glútea: a propósito de un caso / Polymethyl-methacrylate embolism after subcutaneous injection in gluteal region: report of a case

El polimetil-metacrilato es un polímero de alta resistencia al impacto, ampliamente utilizado en diferentes campos de la medicina, sin embargo, aún no está clara su indicación como relleno glúteo. A pesar de su aparente inocuidad, se han presentado complicaciones durante su uso como granulomas y nódulos palpables. Se han reportado casos de embolismo pulmonar por polimetil-metacrilato posterior a vertebroplastias. Sin embargo, no se encontró reporte bibliográfico de casos de embolismo pulmonar con su uso en procedimientos estéticos. Presentamos caso de paciente femenino de 31 años de edad, quien 4 horas luego de la inyección de 500 cm3 de polimetil-metacrilato en cada región glútea, presenta disnea en reposo de aparición súbita con tos seca y palpitaciones, disminución de agudeza visual y petequias generalizadas. Se diagnostica probable embolismo pulmonar por polimetil-metacrilato y retinopatía de Purtscher. Existe similitud clínica e imaginología del caso en estudio con embolismo por silicone, y las imágenes del fondo de ojo semejan la obstrucción de pequeñas arteriolas retinianas compatibles con este diagnóstico. Se sugieren nuevas investigaciones en el uso de polimetil-metacrilato como procedimiento estético en pro de la seguridad y en beneficio de los pacientes

Polymethyl-methacrylate is a high impact resistant polymer, widely used in different medicine fields, however its indication in buttock implants is still not clear. Even though its apparent innocuity, it has presented complications like granulomas and palpable nodules. There have been reported cases of pulmonary embolism caused by polimetil-metacrilato secondary to vertebroplasties. However, there have been no bibliographic cases of pulmonary embolism due to its use in aesthetic procedures. We present a case of a woman patient of 31 years old, who 4 hours after 500 cc injection of polymethyl- Methacrylate in each buttock, presents rest dyspnea with abrupt dry cough and palpitations, reduction in visual acuity and generalized petechiae. It is diagnosed probable pulmonary embolism by polimetil-metacrilato and Purtscher retinopathy. There is a clinical and imaginological similitude between this case and silicone embolism and the images of fondoscopy are similar to those of small retinian arteriole obstruction compatible with the diagnosis. Thereby, it is suggested new investigations in the use of polymethyl-methacrylate as esthetic procedure in favor of the patient’s security and benefit