**4. Algorithms in the preoperative functional assessment**

The use of algorithms in the evaluation of lung function in patients scheduled for thoracic surgery has as the main objective the step standardization of a series of diagnostic tests. These procedures avoid unnecessary costs, save time and allow you to gain experience in a more regulated way. This rationalization process contributes to improved patients care and decreased postoperative morbidity and mortality (Juliá Serdá et al., 2010).

Although several algorithms have been proposed to assess respiratory function in patients undergoing thoracic surgery, there are few validations of them. In addition, they depend on the patients population being served and the technical possibilities of each hospital or center where they are performed (Juliá Serdá et al., 2010).

One of the most widely accepted algorithms was proposed by Bolliger et al. and performed in 80 patients scheduled for resection of lung parenchyma (Bolliger et al. 1995a). This algorithm was validated later by Wyser et al. in 137 patients (figure 1), demonstrating a low postoperative complication rate (11%) and mortality (1.5%) (Wyser et al., 1999).

Fig. 4. Algorithm for assessment of cardiopulmonary reserve before lung resection in lung cancer patients. FEV1: Forced expiratory volume in 1 s. DLCO: Diffusion capacity of the lung for carbon monoxide. ppo: postoperative. VO2: Oxygen uptake. (Brunelli et al., 2009)

Perioperative Pulmonary Functional Assessment 385

Before the surgery, the preoperative VO2 is inversely proportional to the probability of the presence of complications after lung resection (Wu et al., 2002), which, in turn, is associated with postoperative loss of lung function (Nagamatsu et al., 2007). In addition, pulmonary rehabilitation improves VO2 before the surgery in patients with COPD with low VO2 (less than 15 mL/kg/min), which reduces late complications without affecting the operability or

Preoperative training programs lead to a reduction of hospital stay and of complications in patients with COPD and lung cancer (Sekine et al., 2005). However, improved accessibility to intervention has been observed only in patients with "quasi normal" lung function (Lovin et al., 2006). Pulmonary rehabilitation in inpatients has shown benefits in exercise capacity

Therefore, in the light of the data presented, it seems logical that pulmonary rehabilitation may decrease the complication rate in candidates for lung resection, which is why future

The diagnosis of COPD is often established during the preoperative functional assessment in patients scheduled for lung resection after the diagnosis of lung cancer. These patients, with a high percentage of respiratory complications, may be excluded from surgery if we

The main guidelines for the management of COPD patients who are to undergo lung resection indicate that it is necessary that the patient quit smoking, do exercises in pulmonary rehabilitation and optimize proper treatment to improve lung function and reduce postoperative complications (Brunelli et al., 2009). However, the treatments indicated for patients with COPD and lung cancer do not differ from those which are recommended to patients who have only COPD, in which a short-term therapeutic effect is not expected. In the scientific literature we have found only few studies that evaluate the short and long term effect of initiation of therapy in patients with COPD and lung cancer. Several of them value the effect of tiotropium on lung function, establishing its improvement up to 226ml in FEV1 (Kobayashi et al., 2009), but without any effect on post sugery complications (Ueda et al. 2010). In a recent study, the treatment with formoterol and budesonide added to tiotropium improved the FEV1 in 310ml and decreased the number of postoperative pulmonary complications (Bölükbas et al., 2011). One of the keys to these results is the improvement in lung function that occurs when adding corticosteroids to long-acting bronchodilators. Another key is the improvement in FEV1 due to these drugs, since its value, both pre-and postoperative, is associated with mortality and morbidity after the surgery. Therefore, an elevation of FEV1 can increase the number of candidates for surgical resection, thus optimizing the treatment of cancer and improve the prognosis of these

A lot of scientific literature dedicated to pre-operative evaluation before surgical treatment of lung diseases has been published. The search for the ideal preoperative test to predict major perioperative risk of patients began with the use of spirometry in 1955. Since then, scientific evidence allowing the stratification of perioperative risk based in different preoperative pulmonary function tests, estimations of postoperative lung function,

researches on the content and duration of rehabilitation programs are priorities.

fail to achieve, with proper treatment, a sufficient pulmonary function value.

the prognosis (Bobbio et al., 2008).

and lung volumes (Cesario et al., 2007).

**5.3 Pharmacologic therapy** 

patients.

**6. Conclusion** 

Taking into account these issues the ERS / ESTS Task Force has recently published its algorithm based fundamentally on the performance of exercise tests when preoperative FEV1 or DLCO is less than 80%. If in the exercise test VO2 peak is less than 35% or 10 mL/kg/min, it should not be recommendable to perform pneumonectomy or lobectomy, but if it is higher than 75% or 20 mL/kg/min, any resection (including pneumonectomy) would be indicated. If the VO2 peak is between these cutoff values, it would be advisable to calculate ppo-FEV1 and ppo-DLCO. If these are greater than 30%, lung resection would be indicated according to the calculated extension, and if, at least, one of these parameters is less than 30% it would be necessary to calculate the ppo-VO2 peak. After its calculation and if it is greater than 35% or 10 mL/kg/min, resection would be indicated depending on the calculated extension, and if its value is less than this cutoff, neither pneumonectomy nor lobectomy would be recommended. Finally, if it is impossible to perform cardiopulmonary exercise test and calculate the VO2 peak, it is recommendable to carry out the stair climbing test, but if the reached altitude is less than 22 meters, its calculation would be advisable (Brunelli et al., 2009 ) (figure 4).

One limitation in this type of algorithms, focusing on the completion of cardiopulmonary exercise testing, is that some candidates for lung resection are unable to execute any kind of exercise test due to the burden of concomitant comorbidities. These patients have demonstrated increased mortality after lung resection (Brunelli et al., 2005) and, after careful selection based on cardiopulmonary parameters they should be considered as high-risk patients and candidates to be perioperatively monitored.
