Future trends in preoperative evaluation

Performance of wider parenchymal lung resection than preoperatively planned in patients with low preoperative lung function performance undergoing video-assisted thoracic surgery major lung resection

OBJECTIVES

Pulmonary assessment before major lung resections is used to determine patient's operability. In marginal cases, extensive pulmonary assessment is additionally important under the fear of a more radical parenchymal removal. This study investigates the outcome of wider lung parenchymal resections in patients with low lung functional status undergoing video-assisted thoracic surgery (VATS) major lung resection.

METHODS

The medical records of patients who underwent VATS major lung resection for cancer, over a period of 5 years (August 2009-August 2014), were retrospectively reviewed. Patients with postoperative forced expiratory volume in first second (ppoFEV1) or postoperative diffusional capacity for carbon monoxide (ppoDLCO) <40% who underwent wider lung resection than preoperatively planned (Group A) were compared with patients with ppoFEV1 or ppoDLCO <40% who underwent the planned operation (Group B) and patients with ppoFEV1 and ppoDLCO >40% who underwent wider resection than preoperatively planned (Group C). Data analysed included demographics, past medical history, the surgery planned and performed, the reason for higher parenchymal resection, the clinical and pathological stage, the length of stay (LOS), the morbidity, the 30-day mortality and the survival.

RESULTS

Overall, 73 patients were analysed (15 patients in Group A, 50 patients in Group B and 8 patients in Group C). The mean age was 68.5 years and 31.5% were males. The wider lung resection regarded 7 patients who underwent bilobectomy instead of lobectomy and 16 patients who underwent pneumonectomy instead of lobectomy. The main reason for higher resection was the wider invasion of the mass (21 patients). The age, gender and body mass index between three groups were similar, whereas ppoFEV1 and ppoDLCO were different (P < 0.001 and P < 0.001 respectively). Conversions, pulmonary morbidity and the 30-day mortality between groups were similar (P = 0.67, P = 0.88 and P = 0.33, respectively). LOS between groups was not different (P = 0.46). Survival rate between groups was also similar (log-rank, P = 0.79).

CONCLUSIONS

Wider lung parenchymal resection than preoperatively anticipated may be performed, even in patients with low lung functional status, without increased adverse outcome when compared with patients with good lung function. This finding indicates that the preoperative risk stratification based on lung function tests is questionable.

A new method to predict values for postoperative lung function and surgical risk of lung resection by quantitative breath sound measurements

OBJECTIVES

We evaluated quantitative acoustic measurements, as a simpler alternative to perfusion scintigraphy, for estimation of predicted postoperative (ppo) lung function after resection surgery in our patient population.

METHODS

Patients with lung cancer, considered as candidates for lung resection, were enrolled in the study. All patients underwent lung function testing and quantitative breath sound testing by vibration response imaging (VRI) on the same day. A subset of patients also had perfusion testing. Forced expiratory volume in 1 second (FEV(1)) and diffusing capacity of the lung for carbon monoxide (DLCO) predictions derived from VRI testing were compared with perfusion values and actual FEV(1) values at 1 month postoperatively.

RESULTS

Fifty-three subjects (40 males; age 66±8 y) participated. There was high correlation between both methods for the calculation of ppoFEV(1)% (R=0.94; n=39) and ppoFEV (L) (R=0.90; n=39). PpoFEV(1) were 58±18% versus 56±20% and 1.69±0.49 L versus 1.62±0.52 L, based on perfusion and VRI methods, respectively. In 92% (36/39) of calculations, the difference between the 2 methods was <10%. High correlations also existed between VRI and perfusion for the calculation of ppoDLCO% (R=0.95; n=37) and ppoDLCO mL/min/mm Hg (R=0.90; n=37). VRI predictions showed good correlation for the 34 patients with actual postoperative lung function (R=0.88 and R=0.80 for FEV(1)% and FEV(1)L, respectively). Accuracy of the VRI to predict surgical risk (<40% cutoff threshold for ppo values) compared with actual postoperative values was 85% (29/34).

CONCLUSIONS

Predictions of postoperative lung function using VRI agree well with radionuclide techniques and actual measured postoperative values. VRI may provide a noninvasive, simpler alternative for estimation of ppo values, particularly when perfusion testing is not readily available.

Value of the average basal daily walked distance measured using a pedometer to predict maximum oxygen consumption per minute in patients undergoing lung resection

OBJECTIVES

Maximum oxygen consumption per min (VO(₂max)) is currently considered the most accurate test for the preoperative risk assessment in patients scheduled for pulmonary resection. Due to its high-technology requirements and cost, VO(₂max) is performed less frequently than is desired. The objective of this investigation is to determine if the measurement of the basal daily ambulatory activity of the patients, with a pedometer, can be used to predict VO(₂max) values.

METHODS

This is a prospective study on 38 patients referred for scheduled lobectomy or pneumonectomy. Daily basal preoperative activity of the patients was measured 3 weeks before surgery by means of an OMROM HJ-72OIT-E2 pedometer. Before surgery, VO(₂max) (dependent variable) was calculated using a Master Screen CPX module of Jaeger-Vyasis-Healthcare. The following independent variables were studied: age, sex, preoperative forced expiratory volume in 1s percentage (FEV1%) and carbon monoxide diffusing capacity percentage (DLCO%), mean number of steps per day (aerobic and non-aerobic), mean daily time of aerobic activity (in min) and mean daily walked distance (in km). Two linear regression models with bootstrap robust estimation of the standard error of the coefficients were adjusted and the estimated values of VO(₂max) were kept as a new variable for comparison. To avoid collinearity problems, only one of the pedometer records entered the regression model.

RESULTS

Data of the series (mean ± SD): age 62.8 ± 10.14 years; FEV1% 90.1 ± 21.8; DLCO% 82.8 ± 20.1. After collinearity analysis, mean daily walked distance was chosen as the most representative variable. In the first regression model, 'Distance' (p = 0.000) was highly correlated to the dependent variable (adjusted R²: 0.812). The second model improved the predictive value of the first one adding DLCO% to the model. In this model, DLCO% (p = 0.000) and 'Distance' (p = 0.002) were correlated to the dependent variable. The adjusted R² of the second lineal model was 0.935.

CONCLUSION

These preliminary data show that a combination of the measured daily ambulatory activity using a pedometer, especially the mean daily walked distance in km, and the DLCO% of the patient could predict the VO(₂max) value. Larger data series are needed for conclusive results.