Geoffrey Roberts, Cheuk-Bong Tang, Mike Harvey, Sritharan Kadirkamanathan, Department of Upper Gastrointestinal Surgery, Broomfield Hospital, Chelmsford CM1 7ET, United Kingdom.
World J Gastrointest Surg. 2012 Oct 27;4(10):234-7. doi: 10.4240/wjgs.v4.i10.234.
To examine the feasibility of prospective, real-time outcome monitoring in a United Kingdom oesophago-gastric cancer surgery unit.
The first 100 hybrid (laparoscopic abdominal phase, open thoracic phase) Ivor-Lewis oesophagectomies performed by a United Kingdom oesophago-gastric cancer surgery unit were assessed retrospectively using cumulative sum (CUSUM) techniques. The monitored outcome was 30-d post-operative mortality, with the accepted mortality risk defined as 5%. A variable life adjusted display (VLAD) was constructed by plotting a graph of cumulative mortality minus cumulative mortality risk on the y axis vs sequential case number on the x axis. This was modified to a zeroed VLAD by preventing the plot from crossing the y = 0 axis - essentially creating two plots, one examining trends where cumulative mortality was higher than mortality risk (i.e., worse than expected outcomes) where y > 0, and vice versa. Alert lines were set at y = ± 2. At any point where a plot breaches an alert line, it is felt that the 30-d post-operative mortality rate has deviated significantly from that expected and an internal review should be performed.
One hundred cases were assessed, with a mean age of 66.4 years, mean T stage of 2.1, and mean N stage of 0.48. Three cases were commenced using a laparoscopic technique and converted to open surgery due to technical factors. Median length of inpatient stay was 15 d. The crude 30 d mortality was 5% and the incidence of clinically significant anastomotic leak was 6%. The VLAD demonstrated a plot of cumulative mortality minus cumulative mortality risk (i.e., 5% per case) which remained in the range -1.4 to +0.5 excess mortalities. With the alert set at two greater or fewer than predicted mortalities, this method does not approach the point of triggering internal review. It is however arguable that a run of performance that is better than expected, causing the plot to be well below y = 0, would mask a subsequent run of poor performance by requiring a rise of greater than two excess mortalities to trigger the alert line. The zeroed VLAD removes this problem by preventing the plot that is examining above expected mortality from passing below y = 0, and vice versa. In this study period, no audit triggers were reached. It is therefore possible to independently assess runs of good, or poor performance and so target internal audit to the appropriate series of cases. It is important to note this technique allows targeted internal review, in response to both above and below average outcomes. This study has demonstrated the feasibility of prospective outcome monitoring using the above techniques, actual real-time implementation has the potential to pick up and reinforce good practices when performance is better than predicted, and provide an early warning system for when performance falls below that predicted. Further development is possible, including more patient specific risk adjustment using the oesophago-gastric surgery physiological and operative severity score for the enumeration of mortality and morbidity score.
CUSUM techniques provide a potential method of prospective, real-time outcome monitoring in oesophageal cancer surgery.
检验英国胃食管交界癌外科手术单位前瞻性实时结果监测的可行性。
采用累积和（CUSUM）技术回顾性评估英国胃食管交界癌外科手术单位完成的前 100 例杂交（腹腔镜腹部阶段、开放胸部阶段）Ivor-Lewis 食管切除术。监测的结果是 30 天术后死亡率，接受的死亡率风险定义为 5%。通过绘制累积死亡率减去累积死亡率风险在 y 轴上减去序贯病例数在 x 轴上的图形来构建可变生命调整显示（VLAD）。通过防止图穿过 y = 0 轴来修改为零 VLAD - 本质上创建了两个图，一个检查累积死亡率高于死亡率风险（即，结果比预期差）的趋势（即，y > 0），反之亦然。在 y = ± 2 处设置警报线。在任何一个图突破警报线的情况下，人们认为 30 天术后死亡率已经显著偏离预期，应进行内部审查。
评估了 100 例病例，平均年龄为 66.4 岁，平均 T 分期为 2.1，平均 N 分期为 0.48。由于技术因素，有 3 例开始采用腹腔镜技术，然后转为开放手术。住院中位数为 15 天。粗死亡率为 5%，临床显著吻合口漏发生率为 6%。VLAD 显示了累积死亡率减去累积死亡率风险（即每例 5%）的图，该图仍在-1.4 至+0.5 个额外死亡率范围内。将警报设置为两个或更少的预测死亡率，这种方法不会接近触发内部审查的点。然而，可以争辩的是，表现优于预期的运行会导致图远低于 y = 0，从而掩盖随后表现不佳的运行，因为需要超过两个额外的死亡率上升才能触发警报线。零 VLAD 通过防止检查预期以上死亡率的图穿过 y = 0 来解决这个问题，反之亦然。在本研究期间，没有达到审核触发点。因此，可以独立评估表现良好或不佳的运行情况，从而将内部审核目标对准适当的病例系列。重要的是要注意，这种技术允许针对平均以上和以下的结果进行有针对性的内部审查。本研究证明了使用上述技术进行前瞻性结果监测的可行性，实际实时实施有可能在表现优于预期时发现并加强良好实践，并在表现低于预期时提供早期预警系统。进一步的发展是可能的，包括使用食管胃生理和手术严重程度评分对患者进行更具体的风险调整，以评估死亡率和发病率评分。
CUSUM 技术为食管癌手术的前瞻性实时结果监测提供了一种潜在方法。
