Attaining proficiency with endobronchial ultrasound-guided transbronchial needle aspiration

Abstract

Objectives: Endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) is becoming the preferred method of mediastinal staging for lung cancer. We investigated the learning curve for EBUS-TBNA using risk-adjusted cumulative sum (Cusum).

Methods: A retrospective study of EBUS-TBNA was performed at a single academic institution for patients with mediastinal or hilar lymphadenopathy in the setting of proven or suspected lung cancer. A sampling pass was defined as a full retraction and repositioning of the aspiration needle. Rapid on-site evaluation was not available. To track proficiency, risk-adjusted Cusum analysis was performed using acceptable and unacceptable failure rates of 10% and 20%, respectively. Failure was defined as false negative or nondiagnostic results.

Results: During the study period, 231 patients underwent EBUS-TBNA. Prevalence of mediastinal or hilar malignancy was 66.7% (154 out of 231). Sensitivity was 92.2% (142 out of 154), and negative predictive value was 87.9% (58 out of 66). Node size was identified as a significant predictor of EBUS-TBNA success by multiple regression. Risk-adjusted Cusum analysis demonstrated that the first and only unacceptable decision interval was crossed at 22 cases. Individual practitioner learning curves were highly variable, and the operator with the highest volume was the most consistently proficient.

Conclusions: In our experience, attainment of an acceptable failure rate for EBUS-TBNA required 22 cases. Node size is a predictor of EBUS-TBNA success. Risk-adjusted Cusum proved a powerful evaluative tool to monitor the training process of this new procedure.

Keywords: 10; 13; 2; CUSUM; EBUS-TBNA; ROSE; cumulative sum; endobronchial ultrasound-guided transbronchial needle aspiration; rapid on-site pathologic evaluation.

Figure 1

Example risk-adjusted cumulative sum (Cusum) graphs. Positive deflections indicate failed attempts, negative deflections indicate successful attempts. Horizontal lines demarcate unacceptable and acceptable thresholds. From left to right, graphs depict a subpar performer, a performer in the process of training, and a learner reverting to inadequacy after a period of proficiency.

Figure 2

Institutional risk-adjusted cumulative sum (Cusum). Left, Unadjusted Cusum shows that an unacceptable threshold (red lines) was crossed at 32 cases (indicated by *), and only acceptable thresholds (gray lines) are crossed in subsequent cases, indicating proficient performance beyond 32 cases. Right, Risk-adjusted Cusum shows an unacceptable threshold crossed at 22 cases (indicated by *) with subsequent proficiency.

Figure 3

Individual risk-adjusted cumulative sum (Cusum) curves. A, Operator 1 demonstrated proficiency throughout the study period. B, Operator 2 crosses an unacceptable threshold at 27 cases, and then maintains proficiency thereafter. C, Operator 3 has yet to be demonstrate proficiency after 22 cases.