External validation of the Ferguson pulmonary risk score for predicting major pulmonary complications after oesophagectomy

OBJECTIVES: Pulmonary complications remain a frequent cause of morbidity in patients undergoing oesophagectomy. Risk screening tools assist in patient stratification. Ferguson proposed a risk score system to predict major pulmonary complications after oesophagectomy. Our objective was to externally validate this risk score system. METHODS: We analysed our institutional database for patients undergoing oesophagectomy for cancer from August 2009 to December 2012. We analysed patients who had complete documentation of variables used in the Ferguson risk score calculation: forced expiratory volume in the 1 s, diffusion capacity of the lung for carbon monoxide, performance status and age. One hundred and thirty-six patients qualified for analysis in the validation study. Outcome variables measured included major pulmonary complications, defined as need for reintubation for respiratory failure and pneumonia. The risk score was then calculated for each individual based on the model. Incidence of major pulmonary events was assessed in the five risk class groupings to assess the discriminative ability of the Ferguson score. RESULTS: Major pulmonary complications occurred in 35% of patients (47/136). Overall mortality was 6% (8/136). Patients were grouped into five risk categories according to their Ferguson pulmonary risk score: 0-2, 8 patients (6%); 3-4, 24 patients (18%); 5-6, 49 patients (36%); 29 patients (21%); 9-14, 26 patients (19%). The incidence of major pulmonary complications in these categories was 0, 17, 20, 41 and 77%, respectively. The accuracy of the risk score system for predicting major pulmonary complications was 76% (P < 0.0001). CONCLUSIONS: This pulmonary risk scoring system is a reliable instrument to be used during the preoperative phase to differentiate patients who may be at higher risk for pulmonary complications after oesophagectomy. These data can assist in patient selection, and in patient education/informed consent and can guide postoperative management.