CPR scoring explained

We know good CPR gives higher survival rates, and the idea about scoring is to reflect how good the performance really is对病人。

以前，CPR反馈已得到严格批准/未批准的结果。在过去的十年中，Laerdal和我们的合作伙伴创建了一种算法，提供了更详细和颗粒状的CPR分数。让我们以一个例子说明：

Example:认识朱莉（Julie

朱莉（Julie）是英国医院的急诊护士。她身体健康，能够在每种压缩中提供超过50mm的固体深度 - 全部完全释放，绝对没有中断。她是我们见过的最好的CPR表演者之一。尽管如此，在会议结束后，二进制心肺复苏式反馈说她已经失败了。为什么？

The rate of her compressions were a consistent 122 compressions per minute. Clinically superb, but just a tiny bit outside of the magic 100-120-limit in the guidelines. Was it fair to tell her she failed? No. If your life was on the line, you’d want Julie to perform CPR on you.

We saw these results all the time when using the old, binary scoring, and this is one of the reasons we made a new algorithm for scoring CPR.

而其他的提供者CPR得分只使用比娜ry numbers, Laerdal uses a non-binary approach to present a more realistic and lifesaving performance review. The simple reason is that while both 49 mm and 25 mm compression depth is outside of the guideline threshold, 49 is undoubtedly, and by far, a much more desired performance.

• Binary scoring:Simply passed or failed. In the introductory example, Learner 1 had 94% of the compression in the correct range of 50-60 mm. The remaining compressions were outside the guidelines. There is no distinction between for example 25 mm and 49 mm. They are both "inadequate".
• Non-binary numbers:偏差越大，得分降低越大。换句话说，49毫米压缩深度的得分比25 mm好得多。

图1.非二进制评分。
学习者1和2在指南阈值的内部和外部具有相等数量的压缩。但是，学习者2获得更高的分数，因为阈值以外的压缩更接近指南。The same principle is used on all other CPR skills. (figure not to scale, for illustrative purposes only)

构成QCPR分数的算法是由Laerdal Medical与AHA ECC小组委员会成员的密切合作以及2013年188体育直播比分AHA关于CPR质量共识声明的合着者的合作。基于这些专家成员的输入，我们为CPR性能的每个子技能创建了数学模型，例如压缩深度，倾斜，通风量等。

Each compression and ventilation are tracked and scored individually and summed up in the overall score. Even though numbers like average rate can be interesting, averages are not used to calculate the overall score. Similarly, the binary numbers do not affect the score calculation directly.

Subtractive scoring model
的scoring algorithm use a subtractive scoring model where we start off on a perfect score and, if the learners do something wrong, the score is reduced. If you are within the guidelines you will always get a 100% score. If you deviate, the score is reduced.

Plotted along an S-curve, we can see that small deviations give small reductions in the overall score, while large deviations result in large reductions in CPR scores:

Fig.2 : Compression rate on the x-axis, and score on the y-axis.
我们看到，CPR分数在指南阈值的两侧都很快恶化。（仅出于说明目的而不缩放）

A popular feature of our QCPR manikins is the QCPR race where up to six learners can participate in a race to see which one performs the best CPR.

Sometimes we see that while one participant achieves the best score on binary sub-metrics (like adequate depth percentage), another participant will be crowned the winner of the race. The binary sub-metrics (like percentage of adequate depth) will not always help explain the CPR score.

Example 1 - high score with low binary metrics:

Two learner perform 100 compressions. Learner 2 gets a better overall score than learner 1, even though learner 1 had better compression depth if you only look at the binary metrics.

The reason is that learner 2 was靠近在10个不完全“足够”的压缩期间的指南中，学习者1距离不够“足够”的8个压缩过程中的准则很远。

Example 2 - Ventilations over the limit:

在另一个示例中，两个学习者都提供通风过多的空气，并错过了通风子？

假设学习者2给出了610毫升的空气（在临床上还可以），学习者1提供了2000毫升空气，这确实可以损害临床结果。用二进制术语，这些结果是相同的，只是“不够”。但是，从临床角度来看，也以得分术语截然不同。学习者2更接近准则，并获得更高的分数。

有时 - 尤其是对于“仅压缩”会话 - 即使压缩率，深度和释放都是完美的（请参见下图），总分出乎意料地低。

这些课程中许多会议的得分降低来自胸部压缩部分。如果您的压缩被中断，则分数会减少 - 更长的中断会减少得分。

Also worth noting, if you are running a ”Compression only” sessions, the expected chest compression fraction is 100%, as you have no good reasons to stop the compressions. So, if there are interruptions, the score is reduced rather strictly.

Illustration, Compression only session: Rate, depth, and release are all perfect. However, the total score is unexpectedly low. The culprit is the chest compression fraction parameter.

评分的参数数量取决于您使用的MANIKIN或模拟器以及使用的软件或应用程序。

10 parameters used to calculate QCPR score:

• 压缩深度
• Compression rate
• 释放不完整
• 手位置
• Compression per cycle
• 胸部压缩部分（也称为流量分数）
• Ventilation volume
• 通风率
• 前吹气的数量
• Inspiration time in pre-ventilations