Risk-adjusted observed minus expected cumulative sum (RA O-E CUSUM) chart for visualisation and monitoring of surgical outcomes

Figures

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  Figure 1. Example of a risk-adjusted observed minus expected (O-E) chart in thyroid surgery. The chart displays the occurrence of recurrent laryngeal nerve palsy after thyroidectomy for a single surgeon. The curve moves upward if the number of operations with recurrent laryngeal nerve palsy increases above that predicted by the risk model and moves downward if the number decreases. Data originated from a previous study: Duclos, A., Lifante, J.-C., Ducarroz, S., Soardo, P., Colin, C. and Peix, J.- L. (2011), Influence of Intraoperative Neuromonitoring on Surgeons’ Technique During Thyroidectomy. World J Surg, 35: 773-778 2014.https://doi.org/10.1007/soo268-011-0963-4.

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  Figure 2. Example of a risk-adjusted cumulative sum (CUSUM) chart in thyroid surgery. The chart displays the occurrence of recurrent laryngeal nerve palsy after thyroidectomy for a single surgeon. The upper curve detects signals of deterioration in surgical performance, while the lower curve detects signals of improvement. When a curve crosses over its control limit, a signal is detected (shown with circles), indicating a statistically significant change in surgical performance. The graph is subsequently reset to allow further monitoring. In this example, deteriorations were detected at procedures 57 and 192. Data originated from a previous study: Duclos, A., Lifante, J.-C., Ducarroz, S., Soardo, P., Colin, C. and Peix, J.- L. (2011), Influence of Intraoperative Neuromonitoring on Surgeons’ Technique During Thyroidectomy. World J Surg, 35: 773-778 2014. https://doi.org/10.1007/s00268-011-0963-4.

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  Figure 3. Risk-adjusted (A) O-E, (B) CUSUM and (C) O-E CUSUM charts for a single digestive surgeon (n=145 procedures performed between 1 November 2020 and 31 December 2021). The outcome was a composite morbidity–mortality measure of major adverse events occurring either during or in the 30 days following the surgery. (A) In the risk-adjusted O-E chart, the curve first moves downward since the number of major adverse events decreases below that predicted by the risk model, then slowly moves upward while the number of major adverse events increases, and finally moves downward again, with a final difference between observed and expected events of −2.5, that is, 2.5 events potentially avoided during the whole 14-month period. (B) In the risk-adjusted CUSUM chart, the coloured areas mark the sequences of deterioration and improvement, including all procedures between the signal and the last zero value of the subscore. The upper curve detects signals of deterioration in surgical performance at procedures 52 and 90, while the lower curve detects signals of improvement at procedures 33, 101 and 128. (C) In the risk-adjusted O-E CUSUM chart, sequences of deterioration and improvement are reported…