Heart Research, Murdoch Children's Research Institute, Parkville, VIC, Australia.
Department of Cardiology, Royal Children's Hospital, Parkville, VIC, Australia.
Hypertens Res. 2021 Aug;44(8):1009-1016. doi: 10.1038/s41440-021-00657-7. Epub 2021 Apr 9.
Controversy surrounds whether to define resting diastolic blood pressure (DBP) as the onset of the fourth or fifth Korotkoff phase (K4, sound muffling, or K5, sound disappearance) in children and adolescents. Although undetectable in some children (due to sounds continuing to zero cuff pressure), K5 is currently recommended for consistency with adult practice and because K4 can be difficult to discern or undetectable. However, to our knowledge, no studies have specifically assessed the reliability of measuring DBP with K4 and K5 in children and adolescents under exercise conditions. We therefore measured DBP before and immediately after a Bruce protocol stress test in 90 children and adolescents aged 12.3 ± 3.5 years (mean ± SD) in a cardiology clinic setting. When detected, K4 and K5 were 63.5 ± 9.2 and 60.2 ± 12.6 mmHg, respectively, at rest and 59.2 ± 14.6 mmHg (p = 0.028 vs rest) and 52.9 ± 18.3 mmHg (p < 0.001), respectively, immediately post-exercise. K4 and K5 were not detected in 41% and 4% of participants at rest or in 29% and 37% post-exercise, respectively, while K5 resulted in unrealistic DBP values (<30 mmHg) in an additional 11%. Better exercise performance was associated with a more frequent absence of K5 post-exercise, and after excluding participants performing at <10th percentile for age, post-exercise K4 was absent in 23%, and plausible K5 values were not obtained in 59% (p < 0.001). Although neither K4 nor K5 alone were reliable measures of DBP immediately post-exercise, a novel hybrid approach using K4, if detected, or K5, if not, produced reasonable DBP measurements in 97% of participants.
在儿童和青少年中，关于将第四或第五个柯氏音（K4，声音变调，或 K5，声音消失）阶段定义为静息舒张压（DBP）起始的问题存在争议。尽管在一些儿童中无法检测到（由于声音持续到零袖带压力），但目前推荐使用 K5 以保持与成人实践的一致性，并且因为 K4 可能难以辨别或无法检测到。然而，据我们所知，没有研究专门评估在运动条件下使用 K4 和 K5 测量儿童和青少年 DBP 的可靠性。因此，我们在心脏病学诊所环境中测量了 90 名年龄为 12.3 ± 3.5 岁（平均值 ± 标准差）的儿童和青少年在布鲁斯方案压力测试前后的 DBP。当检测到 K4 和 K5 时，在休息时分别为 63.5 ± 9.2 和 60.2 ± 12.6mmHg，而在运动后即刻分别为 59.2 ± 14.6mmHg（p=0.028 与休息时相比）和 52.9 ± 18.3mmHg（p<0.001）。在休息时，41%和 4%的参与者未检测到 K4 和 K5，而在运动后，分别有 29%和 37%的参与者未检测到 K4 和 K5，而 K5 导致另外 11%的不切实际的 DBP 值（<30mmHg）。更好的运动表现与运动后更频繁地没有 K5 相关，在排除了年龄低于第 10 百分位数的参与者后，运动后 K4 缺失率为 23%，而无法获得合理的 K5 值的比例为 59%（p<0.001）。尽管单独使用 K4 或 K5 都不能可靠地测量运动后即刻的 DBP，但使用如果检测到 K4，或者如果没有检测到 K4，则使用 K5 的新型混合方法，可使 97%的参与者获得合理的 DBP 测量值。
