Exercise oximetry versus spirometry in the assessment of risk prior to lung resection

Significance of preoperative exercise oxygen desaturation in lung cancer with interstitial lung disease

OBJECTIVES

Evaluating the diffusing capacity for carbon monoxide (DLco) is crucial for patients with lung cancer and interstitial lung disease. However, the clinical significance of assessing exercise oxygen desaturation (EOD) remains unclear.

METHODS

We retrospectively analysed 186 consecutive patients with interstitial lung disease who underwent lobectomy for non-small-cell lung cancer. EOD was assessed using the two-flight test (TFT), with TFT positivity defined as ≥5% SpO2 reduction. We investigated the impact of EOD and predicted postoperative (ppo)%DLco on postoperative complications and prognosis.

RESULTS

A total of 106 (57%) patients were identified as TFT-positive, and 58 (31%) patients had ppo% DLco < 30%. Pulmonary complications were significantly more prevalent in TFT-positive patients than in TFT-negative patients (52% vs 19%, P < 0.001), and multivariable analysis revealed that TFT-positivity was an independent risk factor (odds ratio 3.46, 95% confidence interval 1.70-7.07, P < 0.001), whereas ppo%DLco was not (P = 0.09). In terms of long-term outcomes, both TFT positivity and ppo%DLco < 30% independently predicted overall survival. We divided the patients into 4 groups based on TFT positivity and ppo%DLco status. TFT-positive patients with ppo%DLco < 30% exhibited the significantly lowest 5-year overall survival among the 4 groups: ppo%DLco ≥ 30% and TFT-negative, 54.2%; ppo%DLco < 30% and TFT-negative, 68.8%; ppo%DLco ≥ 30% and TFT-positive, 38.1%; and ppo%DLco < 30% and TFT-positive, 16.7% (P = 0.001).

CONCLUSIONS

Incorporating EOD evaluation was useful for predicting postoperative complications and survival outcomes in patients with lung cancer and interstitial lung disease.

Assessment and Rehabilitation of the Compromised Patient Prior to Thoracotomy

Patients for whom pulmonary resection is anticipated often have compromised pulmonary function and decreased exercise tolerance. To avoid major morbidity and reduce mortality, identification of the high-risk patient becomes extremely important. The means of identification include rather simple testing modalities as well as those that are more complex, which report specific physiologic data. This article develops a schematic for a logical progression through the assessment of prethoracotomy patients in order that those facing a significant surgical risk might undergo pulmonary rehabilitation to improve exercise performance followed by reassessment prior to surgery.

High Risk for Thoracotomy but not Thoracoscopic Lobectomy

BACKGROUND

Pulmonary lobectomy is the standard of care for resection of non-small cell lung cancer (NSCLC). Patients with compromised lung function who are considered high risk may be denied surgical treatment; thus, proper identification of those truly at high risk is critical. Video-assisted thoracic surgery (VATS) may reduce the operative risk. This study reviews our institutional experience of pulmonary lobectomy by open thoracotomy or VATS techniques in patients deemed to be high risk.

METHODS

A retrospective review of an institutional database was performed for all patients undergoing lobectomy from 2002 to 2010. Patients were grouped into high-risk (HR) and standard-risk (SR) cohorts according to the American College of Surgeons Oncology Group Z4099/Radiation Therapy Oncology Group 1021 criteria.

RESULTS

From 2002 to 2010, 72 HR and 536 SR patients underwent lobectomy. Mean age was 73 years for HR and 66 years for SR (p < 0.0001). Rates of overall (p < 0.0001) and pulmonary complications (p < 0.0001) were significantly higher in the HR group. However, when HR patients were resected by VATS, there was no significant difference in overall (p = 0.1299) or pulmonary complications (p = 0.2292) compared with the SR VATS group. Moreover, overall survival was significantly lower for HR patients who had an open operation compared with VATS lobectomy or SR open (p = 0.0028).

CONCLUSIONS

VATS lobectomy offers patients who are considered to be at increased risk for open lobectomy a feasible procedure, with no difference in overall survival compared with SR patients, and decreased morbidity compared with open lobectomy. VATS lobectomy should be considered for patients who historically may not have been considered for surgical resection.

Physiologic assessment before video thoracoscopic resection for lung cancer in patients with abnormal pulmonary function

BACKGROUND

Impaired respiratory function may prevent curative surgery for patients with non-small cell lung cancer (NSCLC). Video-assisted thoracoscopic surgery (VATS) reduces postoperative morbility-mortality and could change preoperative assessment practices and therapeutic decisions. We evaluated the relation between preoperative pulmonary function tests and the occurrence of postoperative complications after VATS pulmonary resection in patients with abnormal pulmonary function.

METHODS

We included 106 consecutive patients with ≤80% predicted value of presurgical expiratory volume in one second (FEV1) and/or diffusing capacity of carbon monoxide (DLCO) and who underwent VATS pulmonary resection for NSCLC from a prospective surgical database.

RESULTS

Patients (64±9.5 years) had lobectomy (n=91), segmentectomy (n=7), bilobectomy (n=4), or pneumonectomy (n=4). FEV1 and DLCO preoperative averages were 68%±21% and 60%±18%. Operative mortality was 1.89%. Only FEV1 was predictive of postoperative complications [odds ratio (OR), 0.96; 95% confidence interval (CI), 0.926-0.991, P=0.016], but there was no determinable threshold. Twenty-five patients underwent incremental exercise testing. Desaturations during exercise (OR, 0.462; 95% CI, 0.191-0.878, P=0.039) and heart rate (HR) response (OR, 0.953; 95% CI, 0.895-0.993, P=0.05) were associated with postoperative complications.

CONCLUSIONS

FEV1 but not DLCO was a significant predictor of pulmonary complications after VATS pulmonary resection despite a low rate of severe morbidity. Incremental exercise testing seems more discriminating. Further investigation is required in a larger patient population to change current pre-operative threshold in a new era of minimally invasive surgery.

American College of Chest Physicians and Society of Thoracic Surgeons consensus statement for evaluation and management for high-risk patients with stage I non-small cell lung cancer

BACKGROUND

The standard treatment of stage I non-small cell lung cancer (NSCLC) is lobectomy with systematic mediastinal lymph node evaluation. Unfortunately, up to 25% of patients with stage I NSCLC are not candidates for lobectomy because of severe medical comorbidity.

METHODS

A panel of experts was convened through the Thoracic Oncology Network of the American College of Chest Physicians and the Workforce on Evidence-Based Surgery of the Society of Thoracic Surgeons. Following a literature review, the panel developed 13 suggestions for evaluation and treatment through iterative discussion and debate until unanimous agreement was achieved.

RESULTS

Pretreatment evaluation should focus primarily on measures of cardiopulmonary physiology, as respiratory failure represents the greatest interventional risk. Alternative treatment options to lobectomy for high-risk patients include sublobar resection with or without brachytherapy, stereotactic body radiation therapy, and radiofrequency ablation. Each is associated with decreased procedural morbidity and mortality but increased risk for involved lobe and regional recurrence compared with lobectomy, but direct comparisons between modalities are lacking.

CONCLUSIONS

Therapeutic options for the treatment of high-risk patients are evolving quickly. Improved radiographic staging and the diagnosis of smaller and more indolent tumors push the risk-benefit decision toward parenchymal-sparing or nonoperative therapies in high-risk patients. Unbiased assessment of treatment options requires uniform reporting of treatment populations and outcomes in clinical series, which has been lacking to date.

Preoperative Workup and Postoperative Surveillance for Patients Undergoing Pulmonary Metastasectomy

The workup of patients suspected of having pulmonary metastases is complicated by the fact that a high percentage of pulmonary metastases are 6mm or less at presentation. Helical CT scans and high-resolution CT scans currently miss many of the lesions eventually detected at thoracotomy and many of the lesions detected are benign. The follow-up of patients after pulmonary metastasectomy is a controversial topic because of the lack of evidence-based practice guidelines. Though it is unlikely that current follow-up recommendations will ever be tested in randomized controlled trials, meta-analyses of existing retrospective data could improve the quality of the existing literature.

Preoperative pulmonary evaluation of the thoracic surgical patient

Fig. 2 is an algorithm for the preoperative pulmonary evaluation of the lung resection candidate. Patients should undergo routine spirometry and diffusion capacity testing. If the FEV1 and DLCO are greater than 80% predicted, no further study is needed. When these parameters are less than 80%, some estimation of postoperative function is likely needed, taking into account the proposed resection. Patients with ppoFEV1 or ppoDLCO less than 40% are at increased risk of perioperative complications or death and should undergo formal exercise testing. A VO2max or ppoVO2max less than 10 mL/kg/min is associated with prohibitive risk for anatomic lung resection, and alternative treatment modalities should be considered.

Lung cancer: Preoperative pulmonary evaluation of the lung resection candidate

Lung resection provides the best chance of cure for individuals with early stage non-small cell lung cancer. Naturally, lung resection will lead to a decrease in lung function. The population that develops lung cancer often has concomitant lung disease and a reduced ability to tolerate further losses in lung function. The goal of the preoperative pulmonary assessment of individuals with resectable lung cancer is to identify those individuals whose short- and long-term morbidity and mortality would be unacceptably high if surgical resection were to occur. Pulmonary function measures such as the forced expiratory volume in 1 second and the diffusing capacity for carbon monoxide are useful predictors of postoperative outcome. In situations in which lung function is not normal, the prediction of postoperative lung function from preoperative results and the assessment of exercise capacity can be performed to further clarify risks. Published guidelines help to direct the order of testing, permitting us to offer resection to as many patients as possible.

Preoperative Assessment: An Anesthesiologist's Perspective

Advances in anesthesia and surgery have made it so that almost any patient with a resectable lung malignancy is now an operative candidate given a full understanding of the risks and after appropriate investigation. This situation necessitates a change in the paradigm that anesthesiologists use for preoperative assessment. Understanding and stratifying the perioperative risks allows the anesthesiologist to develop a systematic focused approach to these patients at the time of the initial contact and immediately before induction, which can be used to guide anesthetic management.

Optimization of lung function before pulmonary resection: pulmonologists' perspectives

Many risk factors for morbidity and mortality with lung resection have been identified. Factors such as age, gender, and cancer stage cannot be altered, but lung function can be optimized by treating COPD or asthma with bronchodilators, corticosteroids, or antibiotics (when indicated) and by inspiratory muscle training. Although smoking cessation 2 months in advance of surgery may not be feasible, cessation nevertheless should be encouraged because it may decrease postoperative inflammation and in the long-term may decrease the risk of recurrence. In addition, morbidity and mortality can be minimized by careful patient selection using lung scanning or CT to determine predicted postoperative functions (FEV1% and DLco%) and some form of exercise testing, such as cardiopulmonary exercise testing or simple stair climbing. When the risk of surgery is high, any benefit from possible cure must be weighed against the risk of long-term disability or death. Although much data are available to guide clinicians in these decisions, there still is no one test that provides the answer in individual cases. The art and science of medicine must merge at this point.

Acute and chronic reduction of pulmonary function after lung surgery

Pulmonary function is affected by several variables. The more marginal the patient, the more important the preoperative and perioperative assessment becomes. VATS might be tolerated well with regard to pulmonary function in the early postoperative period. It has allowed thoracic surgeons to expand surgical indications to patients that previously would not have been considered.

Preoperative risk assessment for marginal patients requiring pulmonary resection

Surgical resection remains the mainstay of treatment for pulmonary malignancy. The ability of patients to undergo resection is dependent on the anatomic characteristics of the tumor, and the respiratory and cardiovascular status of the patient. There have been recent advances in our understanding of respiratory function in the patient with marginal lung function that have allowed surgical therapy of lung cancer in patients previously deemed inoperable. This review will define the marginal patients who can safely undergo pulmonary resection.

Predicting length of stay out of hospital following lung resection using preoperative health status measures

Studies evaluating predictors of operative outcome for lung resection have focused on physiological measures of cardiorespiratory impairment, but these have proved inadequate. This study evaluated the predictive abilities of six preoperative variables: the global quality of life (QL), social function (SF), and emotional function (EF) scales of the European Organization for the Research and Treatment of Cancer's (EORTC) QLQ-C30 questionnaire, 6-min walk distance (6MWD), forced expiratory volume (FEV1), and diffusion capacity (DLCO). Operative outcome was represented by the surrogate measure length of stay, out of hospital within the first 30 days (LOSOH). A single-centre prospective cohort study evaluating 70 subjects was conducted using multiple regression. LOSOH was bimodally distributed, therefore analysis was undertaken for the entire sample and for two separate groups (A and B). Group B (n = 4) experienced severe complications (LOSOH = 0-5 days) and was too small for statistical analysis. Group A (n = 66) suffered fewer and less severe complications (LOSOH = 14-26 days). For the entire sample, age was the sole predictor of LOSOH (R2 = 0.123, p = 0.003). In Group A, the strongest predictors of LOSOH were global QL score and 6MWD (R2 = 0.224, p < 0.001). LOSOH was inversely correlated with complications. While it remains difficult to predict severe complications in this population, within Group A, health status measures demonstrated a limited ability to predict LOSOH.

Preoperative assessment for pulmonary resection

Because of recent advances in anesthesia and surgery, almost any patient with a resectable lung malignancy is now an operative candidate, given a full understanding of the risks and provided he or she is investigated appropriately. This progress necessitates a change in the paradigm that one uses for preoperative assessment. Understanding and stratifying the perioperative risks allows the anesthesiologist to develop a systematic focused approach to these patients at the time of the initial contact and immediately before induction, which then can be used to guide anesthetic management (Fig. 7).

Utility of standardized exercise oximetry to predict cardiopulmonary morbidity after lung resection

OBJECTIVES

To evaluate if desaturation, measured by finger oximetry on standardized exercise, accurately predicts cardiopulmonary morbidity after pulmonary resection.

METHODS

A prospective observational clinical study was carried out on 81 consecutive lung carcinoma patients scheduled for pulmonary resection from February 1998 to March 1999. Finger oximetry was monitored during an incremental to exhaustion cycle exercise test. The presence or absence of desaturation (cut-off value 90%) during exercise was recorded. Other independent analyzed variables were: age of the patient (over 75th percentile), body-mass index (BMI) (over 75th percentile), presence of major cardiovascular co-morbidity, and calculated postoperative FEV1% (under 25th percentile) according to the number of resected segments (ppoFEV1%). Postoperative cardiopulmonary morbidity was the evaluated dependent outcome. Fisher's exact test and risk calculation on contingency tables were used for statistical analysis.

RESULTS

A lobectomy was performed in 62 cases, a pneumonectomy was performed in 16 cases, and a segmentectomy was performed in three cases. The mean age of the patients was 63.6 years (SD 10.3, range 34-79 years, 75th percentile 72 years), the mean BMI was 25.9 (SD 4.9, range 16.9-38.1, 75th percentile 29.3), and the mean ppoFEV1% was 64.1 (SD 2016.1, range 29.5-98.6, 25th percentile 50.5). In 14 patients exercise desaturation was registered. Postoperative cardiopulmonary morbidity was presented in 32 cases (five deaths). No correlation was found between postoperative morbidity and any of the following variables: age of the patient, BMI, and co-morbidity. On univariate analysis only low ppoFEV1% (P<0.001) was associated with the outcome, so no multivariate analysis has been carried out.

CONCLUSIONS

We have shown that desaturation during standardized exercise in this series adds no relevant information to predict postoperative cardiorespiratory morbidity after lung resection.

Surgical treatment for chronic pleural empyema

Various surgical procedures have been developed in an attempt to alleviate the significant problems caused by chronic pleural empyema. The present study evaluates our 11-year experience of employing a number of therapeutic approaches for chronic empyema. Between 1987 and 1997, 45 consecutive patients underwent treatment for chronic empyema at our hospitals. They comprised 21 patients (47%) presenting with post-tuberculosis, 11 (24%) receiving cancer therapy including pulmonary resection, and 13 (29%) with postpneumonic empyema. Omentopexy, lung resection, and thoracoscopic surgery were performed in 10 (22%), 5 (11%), and 4 (9%) patients, respectively. Poor results of treatment were observed in two of the patients with post-tuberculous empyema, and three of the patients treated for cancer died of recurrence. The other 40 patients remain symptom-free. An improvement in quality of postoperative life was revealed by the exercise test rather than by static spirometry. Optimal therapy for chronic empyema requires selection of the most appropriate first and staged procedures for each patient. Moreover, lung resection should be minimal. In a critical state, open thoracostomy must be performed as the first procedure, while omentopexy or thoracoplasty should be restricted to selected cases. Dead space and minor air leakage may safely be left behind. A video-assisted procedure can be selected for postpneumonia empyema.

Predictive respiratory complication quotient predicts pulmonary complications in thoracic surgical patients

BACKGROUND

This study was designed to develop an accurate preoperative index of prediction of outcome and hospital charges after lung resection with standard available pulmonary tests in a tertiary cancer center.

METHODS

Sixty-one consecutive patients undergoing pulmonary resections were evaluated. All patients underwent spirometry, carbon monoxide diffusion capacity, split lung function testing, and room air blood gas analysis at rest and after a 2-minute step climb. The thoracic prospective data base and patient charts were reviewed for length of hospitalization, postoperative length of stay, and complications requiring therapy. Logistic regression analysis of the preoperative data, operation and postoperative outcome was used to develop a new postoperative predictive index: the predictive respiratory complication quotient (PRQ). We describe the design of the equation for the probability of serious pulmonary complications, hospital stay, and hospital charges based on PRQ.

RESULTS

Ten of 12 patients with a PRQ less than 2,200 suffered serious pulmonary complications of pneumonia, respiratory insufficiency, hypoxemia, and death. Forty-nine patients with a PRQ more than 2,200 did not experience any pulmonary complications. Postoperative length of stay and hospital charges correlated with the PRQ.

CONCLUSIONS

A construct such as the PRQ may provide a better prediction of outcome than its individual parts. We identified an important underlying relationship between intensive care unit stay, hospital stay and charges, and our index. A PRQ of less than 2,200 was associated with an increased risk of pulmonary complications and mortality.

The surgical treatment of pulmonary metastases

The surgical management of pulmonary metastases remains controversial, as no randomized trials have compared surgical excision with nonoperative treatment (to our knowledge). A Medline-generated review of the literature was undertaken to determine the factors influencing survival following metastasectomy in published trials. In the absence of randomized comparative trials, data must remain inferential and circumstantial. However, the literature does support the anecdotal observation that patients with metastatic disease can achieve long-term survival following surgical excision, irrespective of the source of the primary neoplasm, if there is no demonstrable extrathoracic disease and complete excision of the pulmonary disease is possible. Other factors noted as influencing survival appear to be anecdotal and variable from report to report. Pulmonary metastasectomy should be considered in patients with sufficient pulmonary reserve when the lung is the only site of metastatic disease and the lesions can be totally excised. An algorithm is proposed for a logical approach to the problem.

Predicting Postoperative Outcome

Pulmonary complications are the main source of postop erative morbidity and mortality, with respiratory failure and pneumonia resulting in 50% of postoperative deaths after lung surgery. Despite the high incidence of postop erative complications, pulmonary resection remains the only effective treatment for lung cancer. Substantial resources are ascribed for the perioperative care of these high-risk patients. Clinical experience would dic tate that predicting outcome could be of immense value in allocating resources. This review will consider the predictive value of preoperative testing, including spi rometry, split lung function, blood gas analysis, carbon monoxide diffusion capacity, pulmonary vascular resis tance, and exercise testing, as well as recent efforts to develop a combined cardiopulmonary index.

Standardized exercise oximetry predicts postpneumonectomy outcome

BACKGROUND

We have developed a safe, simple, and easily performed standardized exercise oximetry outpatient test to assess patients undergoing lung resections. We studied its ability to predict outcome after pneumonectomy in 46 consecutive patients over a 5-year period.

METHODS

Room air oximetry is initially performed at rest. The patient then begins to exercise on a stair-stepper apparatus (Stamina Stepper), which provides uniform resistance to stepping. Oxygen saturation values are noted at 10, 20, and 30 steps, equivalent to climbing three flights of stairs. Group 1 consisted of the patients who either had a resting saturation less than 90%, or desaturation greater than or equal to 4% during exercise. Group 2 consisted of all patients who had a preoperative forced expiratory volume in 1 second of 60% or less. Group 3 consisted of all patients who had a predicted postoperative forced expiratory volume in 1 second of 40% or less. Group 4 consisted of patients who had a predicted postoperative diffusing capacity of 40% or less.

RESULTS

There were four deaths (8.6%), 12 patients (26%) remained in the intensive care unit 4 or more days, and 11 patients (23%) suffered major morbidity. Desaturation during exercise (group 1) significantly predicted longer intensive care unit stay (p = 0.0002) and incidence of major morbidity (p < 0.0001). Groups 2, 3, and 4 were not significantly predictive of either longer intensive care unit stay or major morbidity.

CONCLUSIONS

Standardized exercise oximetry performed in the outpatient facility is highly predictive of major morbidity and prolonged intensive care unit stay after pneumonectomy.

Early and late morbidity in patients undergoing pulmonary resection with low diffusion capacity

BACKGROUND

We sought to determine whether low diffusion capacity of the lung to carbon monoxide (DLCO) is a predictor of high postoperative mortality and morbidity after major pulmonary resection and whether major pulmonary resection in patients with low DLCO results in substantial long-term morbidity.

METHODS

Sixty-two major pulmonary resections were performed in 61 patients with low DLCO (DLCO < or = 60% predicted for pneumonectomy or bilobectomy; < or = 50% predicted for lobectomy). Contemporaneously, 262 other patients underwent 263 major pulmonary resections (group II). Long-term morbidity was assessed in subsets of patients with low (n = 24) and high (n = 22; DLCO > 60% predicted) DLCO.

RESULTS

The hospital mortality rates were equivalent (4.8% low DLCO versus 4.9% group II), whereas respiratory complications were more frequent in patients with low DLCO (18% versus 9.5%; p = 0.05). In the subgroup analyses, patients with low DLCO had more hospitalizations for respiratory compromise and worse median dyspnea scores. Analysis of patients with substantial dyspnea revealed an association with extended pulmonary resection and postoperative radiation therapy in patients with low DLCO.

CONCLUSIONS

Patients with low DLCO underwent major pulmonary resection with a low mortality rate and an acceptable, but increased, respiratory complication rate. Long-term respiratory morbidity was increased in patients with low DLCO; however, the extent of pulmonary resection and the use of postoperative radiation therapy may have contributed to the development of dyspnea in these patients.