Cardiopulmonary function after lobectomy or pneumonectomy for pulmonary neoplasm

Intraoperative Variables Enhance the Predictive Performance of Myocardial Injury in Patients with High Cardiovascular Risk After Thoracic Surgery When Added to Baseline Prediction Model

Purpose

Myocardial injury after non-cardiac surgery is closely related to major adverse cardiac and cerebrovascular event and is difficult to identify. This study aims to investigate how to predict the myocardial injury of thoracic surgery and whether intraoperative variables contribute to the prediction of myocardial injury.

Methods

The prospective study included adult patients with high cardiovascular risk who underwent elective thoracic surgery from May 2022 to October 2022. Multivariate logistic regression was used to establish a model with baseline variables and a model with baseline and intraoperative variables. We compare the predictive performance of two models for postoperative myocardial injury.

Results

In general, 31.5% (94 of 298) occurred myocardial injury. Age ≥65 years old, obesity, smoking, preoperative hsTnT, and one-lung ventilation time were independent predictors of myocardial injury. Compared with baseline model, the intraoperative variables improved model fit, modestly improved the reclassification (continuous net reclassification improvement 0.409, 95% CI, 0.169 to 0.648, P<0.001, improved integrated discrimination 0.036, 95% CI, 0.011 to 0.062, P<0.01) of myocardial injury cases, and achieved higher net benefit in decision curve analysis.

Conclusion

The risk stratification and anesthesia management of high-risk patients are essential. The addition of intraoperative variables to the baseline predictive model improved the performance of the overall model of myocardial injury and helped anesthesiologists screen out the patients at the greatest risk for myocardial injury and adjust anesthesia strategies.

Effects and tolerability of exercise therapy modality on cardiorespiratory fitness in lung cancer: a randomized controlled trial

BACKGROUND

Poor cardiorespiratory fitness (CRF) is a cardinal feature of post-treatment primary lung cancer. The most effective exercise therapy regimen to improve CRF has not been determined.

METHODS

In this parallel-group factorial randomized controlled trial, lung cancer survivors with poor CRF (below age-sex sedentary values) were randomly allocated to receive 48 consecutive supervised sessions thrice weekly of (i) aerobic training (AT)-cycle ergometry at 55% to >95% of peak oxygen consumption (VO₂ peak); (ii) resistance training (RT)-lower and upper extremity exercises at 50-85% of maximal strength; (iii) combination training (CT)-AT plus RT; or (iv) stretching attention control (AC) for 16 weeks. The primary endpoint was change in CRF (VO₂ peak, mL O₂ ·kg^-1 ·min^-1 ). Secondary endpoints were body composition, muscle strength, patient-reported outcomes, tolerability (relative dose intensity of exercise), and safety. Analysis of covariance determined change in primary and secondary endpoints from baseline to post-intervention (Week 17) with adjustment for baseline values of the endpoint and other relevant clinical covariates.

RESULTS

Ninety patients (65 ± 9 years; 66% female) were randomized (AT, n = 24; RT, n = 23; CT, n = 20; and AC, n = 23) of the planned n = 160. No serious adverse events were observed. For the overall cohort, the lost-to-follow-up rate was 10%. Mean attendance was ≥75% in all groups. In intention-to-treat analysis, VO₂ peak increased 1.1 mL O₂ ·kg^-1 ·min^-1 [95% confidence interval (CI): 0.0, 2.2, P = 0.04] and 1.4 mL O₂ ·kg^-1 ·min^-1 (95% CI: 0.2, 2.5, P = 0.02) in AT and CT, respectively, compared with AC. There was no difference in VO₂ peak change between RT and AC (-0.1 mL O₂ ·kg^-1 ·min^-1 , 95% CI: -1.2, 1.0, P = 0.88). Favourable improvements in maximal strength and body composition were observed in RT and CT groups compared with AT and AC groups (Ps < 0.05). No between-group changes were observed for any patient-reported outcomes. Relative dose intensity of exercise was lower in RT and CT compared with AT (Ps < 0.05).

CONCLUSIONS

In the context of a smaller than planned sample size, AT and CT significantly improved VO₂ peak in lung cancer survivors; however, the tolerability-to-benefit ratio was superior for AT and hence may be the preferred modality to target impaired CRF in post-treatment lung cancer survivors.

Case Studies in Physiology: Cardiopulmonary exercise testing and inspiratory muscle training in a 59-year-old, four years after an extra-pleural pneumonectomy

This case report characterizes the physiological responses to incremental cycling and determines the effects of 12 weeks of inspiratory muscle training (IMT) on respiratory muscle strength, exercise capacity and dyspnea in a physically active 59-year-old female, four years after a left-sided extra-pleural pneumonectomy (EPP). On separate days, a symptom limited incremental exercise test and a constant work rate (CWR) test at 75% of peak work rate (WR) were completed, followed by 12 weeks of IMT and another CWR test. IMT consisted of two sessions of 30 repetitions twice daily for 5 days per week. Physiological and perceptual variables were measured throughout each exercise test. The participant had a total lung capacity that was 43% predicted post-EPP. A rapid and shallow breathing pattern was adopted throughout exercise, and the ratio of minute ventilation to carbon dioxide output was elevated for a given work rate. Oxygen uptake was 74%predicted and WR was 88%predicted. Following IMT, maximal inspiratory pressure improved by 36% (-27.1 cmH₂O) and endurance time by 31s, with no observable changes in any submaximal or peak cardiorespiratory variables during exercise. The intensity and unpleasantness of dyspnea increased by 2 and 3 Borg 0-10 units, respectively, at the highest equivalent submaximal exercise time achieved on both tests. Despite having undergone a significant reduction in lung volume post-EPP, the participant achieved a relatively normal peak incremental WR, which may reflect a high level of physical conditioning. This case report also demonstrates that IMT can effectively increase respiratory muscle strength several years following EPP.

Impact of diffusing lung capacity before and after neoadjuvant concurrent chemoradiation on postoperative pulmonary complications among patients with stage IIIA/N2 non-small-cell lung cancer

BACKGROUND AND OBJECTIVE

This study aims to evaluate the impact of diffusing capacity of the lung for carbon monoxide (DLco) before and after neoadjuvant concurrent chemoradiotherapy (CCRT) on postoperative pulmonary complication (PPC) among stage IIIA/N2 non-small-cell lung cancer (NSCLC) patients.

METHODS

We retrospectively studied 324 patients with stage IIIA/N2 NSCLC between 2009 and 2016. Patients were classified into 4 groups according to DLco before and after neoadjuvant CCRT; normal-to-normal (NN), normal-to-low (NL), low-to-low (LL), and low-to-very low (LVL). Low DLco and very low DLco were defined as DLco < 80% predicted and DLco < 60% predicted, respectively.

RESULTS

On average, DLco was decreased by 12.3% (±10.5) after CCRT. In multivariable-adjusted analyses, the incidence rate ratio (IRR) for any PPC comparing patients with low DLco to those with normal DLco before CCRT was 2.14 (95% confidence interval (CI) = 1.36-3.36). Moreover, the IRR for any PPC was 3.78 (95% CI = 1.68-8.49) in LVL group compared to NN group. The significant change of DLco after neoadjuvant CCRT had an additional impact on PPC, particularly after bilobectomy or pneumonectomy with low baseline DLco.

CONCLUSIONS

The DLco before CCRT was significantly associated with risk of PPC, and repeated test of DLco after CCRT would be helpful for risk assessment, particularly in patients with low DLco before neoadjuvant CCRT.

Changes in Simple Spirometric Parameters After Lobectomy for Bronchial Carcinoma

Introduction: The purpose of this study was to describe the postoperative changes in lung function after pure open lobectomy for lung carcinoma.

Methods: 30 patients (mean age 64 ± 7 years old, 16 men and 14 women) underwent a left or right lobectomy. They underwent spirometric pulmonary tests preoperatively, and at 1 and 6 months after the operation.

Results: The average preoperative forced expiratory volume in 1 second (FEV1) was 2.55±0.62lt and the mean postoperative FEV1 at 1 and 6 months was 1.97 ± 0.59 L and 2.15±0.66 L respectively. The percentage losses for FEV1 were 22.7% and 15.4% after 1 and 6 months respectively. An average percentage increase of 9.4% for FEV1 was estimated at the time of 6 months in comparison with this of 1 month after the operation. The average preoperative forced vital capacity (FVC) was 3.17 ± 0.81 L and the mean postoperative FVC at 1 and 6 months after the operation was 2.50 ± 0.63 L and 2.72 ± 0.67 L respectively. The percentage losses for FVC were 21.1% and 14.2% after 1 and 6 months respectively. An average percentage increase of 8.7% was observed at the time period of 6 months in comparison with this of 1 month after the operation.

Conclusion: Although, we observed a significant decrease in FEV1 and FVC after the operation, all patients were in excellent clinical status. FEV1 and FVC of 6 months were increased in comparison with the respective values of 1 month after the operation, but did not reach the preoperative values in any patient.

Cardiac Function and Position More Than 5 Years After Pneumonectomy

BACKGROUND

Pneumonectomy not only reduces the pulmonary vascular bed but also changes the position of the heart and large vessels, which may affect the function of the heart. We investigated long-term effects of pneumonectomy on right ventricular (RV) and left ventricular (LV) function and whether this function is influenced by the side of pneumonectomy or the migration of the heart to its new position.

METHODS

In 15 patients who underwent pneumonectomy and survived for more than 5 years, we evaluated by dynamic magnetic resonance imaging the function of the RV and LV and the position of the heart within the thorax.

RESULTS

Long-term effect of pneumonectomy on the position of the heart is characterized by a lateral shift after right-sided pneumonectomy and rotation of the heart after left-sided pneumonectomy. Postoperatively, heart rate was high (p = 0.006) and stroke volume was low (p = 0.001), compared with the reference values, indicating impaired cardiac function. Patients after right-sided pneumonectomy had an abnormal low RV end-diastolic volume of 99 +/- 29 mL together with a normal LV function. No signs of RV hypertrophy were found. In left-sided pneumonectomy patients, RV volumes were normal whereas LV ejection fraction was abnormally low.

CONCLUSIONS

The long-term effects of pneumonectomy on the position of the heart are characterized by a lateral shift in patients after right-sided pneumonectomy and rotation of the heart in patients after left-sided pneumonectomy. Overall, cardiac function in long-term survivors after pneumonectomy is compromised, and might be explained by the altered position of the heart.

Reconstruction of the Pulmonary Artery

Sleeve resection and prosthetic reconstruction of the pulmonary artery have progressively gained acceptance as an alternative to pneumonectomy in lung cancer surgery. Previous concern was mainly related to technical difficulties, intraoperative and postoperative complications, lack of long-term survival, and impact on cardiopulmonary function. For this reason it was not until very recently that lobectomy associated with resection and reconstruction of the pulmonary artery, associated or not to a sleeve resection of the bronchus, has been demonstrated to be an advantageous alternative. The concern about an increased complication rate has been proven to be excessive; in fact, pulmonary artery reconstruction can be performed safely and effectively with the correct indications and technique. We hereby report our experience, along with a review of the indications, the surgical technique, and outcome of pulmonary artery reconstruction.

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.

Functional evaluation before lung resection

Advances in operative technique and perioperative care have reduced surgical morbidity and mortality considerably after pulmonary resections. Various single and combined parameters of functional operability have been proposed to assess the surgical risk. Patients with normal or only slightly impaired pulmonary function (FEV1 and DLCO > or = 80% predicted) and no cardiovascular risk factors can undergo pulmonary resections up to a pneumonectomy without further investigation. For others, exercise testing, pulmonary split-function studies, or a combination of these methods are recommended. Cardiopulmonary exercise testing, most frequently performed as a symptom-limited test with the measurement of VO2max, assesses the pulmonary and cardiovascular reserves. A VO2max of less than 10 mL/kg/minute generally is considered prohibitive for any resection, a value of greater than 20 mL/kg/minute or greater than 75% predicted normal, safe for major resections. Split-function studies are radionuclide-based estimations of the ppo values of various parameters. The currently used ppo parameters are FEV1-ppo, DLCO-ppo, and VO2max-ppo. Suggested cutoff values for safe resection are: FEV1-ppo and DLCO-ppo 40% or greater than predicted, and V(r)O2max-ppo 35% or greater than predicted, combined with an absolute value of greater than or equal to 10 mL/kg/minute. The lowest acceptable ppo values remain to be confirmed by additional prospective studies. Resections involving not more than one lobe usually lead to an early functional deficit followed by recovery. The permanent loss in pulmonary function is small (approximately 10%) and exercise capacity is reduced only slightly or not at all. Pneumonectomy leads to an early permanent loss of about 33% in pulmonary function and approximately 20% in exercise capacity. Pulmonary function tests alone therefore overestimate the functional loss after lung resection.

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).

Pathophysiology of Postpneumonectomy Pulmonary Edema

Pulmonary edema is a rare, potentially fatal complica tion associated with major resection of the lung, usually pneumonectomy. Although pulmonary edema in this setting can often be attributed to a variety of causes such as cardiac failure, bacterial pneumonia, and fluid overload, the specific syndrome of postpneumonec tomy pulmonary edema (PPE) occurs in the absence of these factors. PPE remains a diagnosis of exclusion, and its pathophysiology is poorly understood. Overzealous perioperative fluid administration has traditionally been implicated in clinical cases of postpneumonectomy pulmonary edema, but there is a body of evidence suggesting several other potential mechanisms. These include increases in cardiac output secondary to cat echolamine release, interruption of mediastinal lym phatic drainage, endothelial injury secondary to release of humoral factors or stretching of intercellular junc tions, hyperinflation, and other unknown factors.

Lung function 4 years after lung volume reduction surgery for emphysema

STUDY OBJECTIVES

Current data for patients > 2 years after lung volume reduction surgery (LVRS) for emphysema is limited. This prospective study evaluates pre-LVRS baseline data and provides long-term results in 26 patients.

INTERVENTION

Bilateral targeted upper lobe stapled LVRS using video thoracoscopy was performed in 26 symptomatic patients (18 men) aged 67 +/- 6 years (mean +/- SD) with severe and heterogenous distribution of emphysema on lung CT. Lung function studies were measured before and up to 4 years after LVRS unless death intervened.

RESULTS

No patients were lost to follow-up. Baseline FEV(1) was 0.7 +/- 0.2 L, 29 +/- 10% predicted; FVC, 2.1 +/- 0.6 L, 58 +/- 14% predicted (mean +/- SD); maximum oxygen consumption, 5.7 +/- 3.8 mL/min/kg (normal, > 18 mL/min/kg); dyspneic class > or = 3 (able to walk < or = 100 yards) and oxygen dependence part- or full-time in 18 patients. Following LVRS, mortality due to respiratory failure at 1, 2, 3, and 4 years was 4%, 19%, 31%, and 46%, respectively. At 1, 2, 3, and 4 years after LVRS, an increase above baseline for FEV(1) > 200 mL and/or FVC > 400 mL was noted in 73%, 46%, 35%, and 27% of patients, respectively; a decrease in dyspnea grade > or = 1 in 88%, 69%, 46%, and 27% of patients, respectively; and elimination of oxygen dependence in 78%, 50%, 33%, and 22% of patients, respectively. The mechanism for expiratory airflow improvement was accounted for by the increase in both lung elastic recoil and small airway intraluminal caliber and reduction in hyperinflation. Only FVC and vital capacity (VC) of all preoperative lung function studies could identify the 9 patients with significant physiologic improvement at > 3 years after LVRS, respectively, from 10 patients who responded < or = 2 years and died within 4 years (p < 0.01).

CONCLUSIONS

Bilateral LVRS provides clinical and physiologic improvement for > 3 years in 9 of 26 patients with emphysema primarily due to both increased lung elastic recoil and small airway caliber and decreased hyperinflation. The 9 patients had VC and FVC greater at baseline (p < 0.01) when compared to 10 short-term responders who died < 4 years after LVRS.

Sleeve resection and prosthetic reconstruction of the pulmonary artery for lung cancer

BACKGROUND

Lobectomy associated with reconstruction of the pulmonary artery (PA) is a technically feasible alternative to pneumonectomy in patients with lung cancer. However, concern about postoperative complications and long-term survival limited its acceptance so far.

METHODS

Between 1989 and 1996, we performed a PA reconstruction in 52 patients (41 men, 11 women; age range 35 to 75 years, mean 60 years) with lung cancer. Eleven patients had induction chemotherapy. We performed 15 PA sleeve resections, 34 PA reconstructions by a pericardial patch, and three PA reconstructions by a pericardial conduit, associated with a bronchial sleeve lobectomy or bilobectomy (33), or with standard lobectomy (19). Immediate and long-term postoperative evaluation included spirometry, echocardiography, perfusion lung scans, computed tomography, and PA angiography. The follow-up ranged between 27 and 96 months and is complete for all patients.

RESULTS

We had one specific postoperative complication (PA thrombosis) and no mortality. Perfusion scans and PA angiography were normal in all but the 1 patient having thrombosis. Mean forced expiratory volume (FEV) in 1 s and forced vital capacity (FVC) were, respectively, 72% and 80% preoperatively, 65% and 76% 1 month after surgery, and then they plateaued at 70% and 78% after 6 months. Echocardiography showed patterns in the normal range and normal estimates of PA pressures in all but 2 patients. Five-year survival was 38.3% for the entire group, 18.6% for stages IIIA and B, and 64.4% for stages I and II.

CONCLUSIONS

Morbidity, mortality, and functional data do not differ from what is currently reported for standard lobectomy. Long-term survival is in line with that reported for standard resection. These data support PA reconstruction as a viable option in the treatment of lung cancer.

Longterm effects of pulmonary resection on cardiopulmonary function

BACKGROUND

Major lung resection decreases ventilatory capacity and reduces exercise tolerance, impairing postoperative quality of life. But we have often seen respiratory symptoms improve during several years of postoperative followup. In the current study, we evaluated postoperative changes in cardiopulmonary function on exertion of patients with lung cancer surviving for more than three years, and the corresponding changes of their respiratory symptoms.

METHODS

The effects of pulmonary resection on cardiopulmonary function were evaluated in eight patients with lung cancer. Pulmonary function tests and hemodynamic study at rest and during exercise were performed before, in the early (4 to 6 months) and late (42 to 48 months) postoperative phases after major lung resection.

RESULTS

None of the eight patients had any remarkable symptoms before lung resection. In the early postoperative study, the general condition of five patients deteriorated compared with their preoperative status. In the late postoperative study, four patients showed an improvement of their daily activities from the early postoperative phase. Pulmonary function in the late postoperative phase did not show major changes except for airway resistance and percentage of carbon monoxide diffusing capacity as compared with the early phase, which showed deterioration as compared with the preoperative period. Cardiac index and stroke volume index were significantly decreased during exercise on maximal effort in the late postoperative phase compared with other phases. These results suggest that the peak blood flow per unit of remaining lung during exercise becomes lower with time after lung resection, indicating deterioration of the condition of the pulmonary vascular bed. The deterioration was also revealed from the pressure-flow curve.

CONCLUSIONS

The condition of the pulmonary vascular bed after major lung resection does not improve, even in the late postoperative phase, although clinical symptoms were sometimes improved compared with the early postoperative period.

Effect of thoracotomy and lung resection on exercise capacity in patients with lung cancer

BACKGROUND

Resection is the treatment of choice for lung cancer, but may cause impaired cardiopulmonary function with an adverse effect on quality of life. Few studies have considered the effects of thoracotomy alone on lung function, and whether the operation itself can impair subsequent exercise capacity.

METHODS

Patients being considered for lung resection (n = 106) underwent full static and dynamic pulmonary function testing which was repeated 3-6 months after surgery (n = 53).

RESULTS

Thoracotomy alone (n = 13) produced a reduction in forced expiratory volume in one second (FEV1; mean (SE) 2.10 (0.16) versus 1.87 (0.15) l; p<0.05). Wedge resection (n = 13) produced a non-significant reduction in total lung capacity (TLC) only. Lobectomy (n = 14) reduced forced vital capacity (FVC), TLC, and carbon monoxide transfer factor but exercise capacity was unchanged. Only pneumonectomy (n = 13) reduced exercise capacity by 28% (PVO2 23.9 (1.5) versus 17.2 (1.7) ml/min/kg; difference (95% CI) 6.72 (3.15 to 10.28); p<0.01) and three patients changed from a cardiac limitation to exercise before pneumonectomy to pulmonary limitation afterwards.

CONCLUSIONS

Neither thoracotomy alone nor limited lung resection has a significant effect on exercise capacity. Only pneumonectomy is associated with impaired exercise performance, and then perhaps not as much as might be expected.

Post-pneumonectomy pulmonary edema: is anesthesia to blame?

Post-pneumonectomy pulmonary edema is a major cause of early mortality following lung resection surgery. It is not clear whether this complication is caused by excessive perioperative intravenous fluid as was previously thought. The recent demonstration of increased pulmonary capillary permeability of the lung following a pneumonectomy suggests measures to try and decrease the incidence of this highly lethal syndrome. These measures include the judicious use of intravenous crystalloids, avoidance of lung hyperinflation and efforts to minimize the pulmonary artery pressure.

Recovery and limitation of exercise capacity after lung resection for lung cancer

OBJECTIVE

To assess the effects of pulmonary resection for lung cancer on postoperative recovery and limitation of exercise capacity.

METHODS

Eighty-two patients (20 pneumonectomies, 62 lobectomies) underwent spirometric pulmonary tests and exercise capacity tests preoperatively, and at 3 months and more than 6 months after the operation.

RESULTS

In the lobectomy group, FEV1 vital capacity (VC), and maximum oxygen consumption (VO2max) decreased significantly 3 months after the operation and improved after more than 6 months, but did not reach the preoperative values. In the pneumonectomy group, FEV1 VC, and VO2max decreased 3 months after the surgery and the values did not recover thereafter. In comparison with preoperative values, the functional percentage losses after more than 6 months for lobectomies and pneumonectomies were 11.2% and 36.1% for FEV1, 11.6% and 40.1% for VC, and 13.3% and 28.1% for VO2max, respectively. Postoperatively, maximal minute ventilation (VEmax), the maximal heart rate percentage, and maximal O2 pulse during the exercise test significantly decreased in both the lobectomy and pneumonectomy groups. Nevertheless, VEmax and O2 pulse improved more than 6 months after lobectomy compared with the value at 3 months, but not after pneumonectomy. Breathing reserve did not differ before and after surgery in the lobectomy group, although it decreased significantly after surgery in the pneumonectomy group. Subjectively, postoperative exercise after lobectomy was limited by leg discomfort (64% at more than 6 months after surgery); after pneumonectomy, exercise was limited by dyspnea (60%).

CONCLUSIONS

These results suggest that there are differences between lobectomy and pneumonectomy for lung cancer in terms of recovery and limitation of exercise capacity.

Cardiopulmonary function at rest and during exercise after resection for bronchial carcinoma

BACKGROUND

Measurements of postoperative spirometric values after pneumonectomy and lobectomy vary considerably, and few researchers have studied the changes in exercise capacity during maximal work after lung resection. The purpose of this study was to describe the postoperative alterations in cardiopulmonary function.

METHODS

Ninety-seven consecutive patients with lung malignancy were prospectively examined with maximal exercise test, spirometry, and arterial gas tensions. Fifty-seven patients were reinvestigated 6 months postoperatively.

RESULTS

In patients having lobectomy, forced expiratory volume in 1 second decreased 8%, and exercise capacity, expressed by maximal oxygen uptake and maximal work rate, significantly decreased 13%. In patients having pneumonectomy forced expiratory volume in 1 second significantly decreased 23%, but the loss in lung volume was partly compensated as measured by exercise capacity, which decreased only 16%. Generally patients with the smallest preoperative forced vital capacity had the smallest postoperative deterioration expressed in percentages. We found a weak correlation between alterations in maximal oxygen uptake and lung function after resection.

CONCLUSIONS

Lobectomy is associated with only minor deterioration of lung function and exercise capacity. Pneumonectomy causes a decrease in pulmonary volumes to about 75% of the preoperative values, partly compensated in better oxygen uptake, which postoperatively was about 85% of the preoperative values. Alteration in forced expiratory volume in 1 second is a poor predictor of change in exercise capacity after pulmonary resection.

Video-assisted thoracoscopic volume reduction surgery in patients with diffuse pulmonary emphysema: gas exchange and anesthesiological management

Arterial blood gases were studied prospectively using continuous intraarterial blood gas monitoring during thoracoscopic volume reduction surgery (VRS) in 24 patients with advanced diffuse pulmonary emphysema. Additionally, the early postoperative course (48 h) of arterial blood gases was studied retrospectively. Twenty-six operations were performed using a combination of thoracic epidural and general anesthesia with left-sided double-lumen intubation for one-lung ventilation (OLV). Arterial blood gases were determined awake, during two-lung ventilation prior to surgery, during OLV (extreme values), and after tracheal extubation. Additionally, the extremes during the whole procedure were determined: avoiding excessive peak inspiratory pressures (26.4 +/- 7.0 cm H2O), minimum PaO2 was 77 +/- 39 mm Hg (mean +/- SD), maximum PaCO2 65 +/- 14 mm Hg (P < 0.0001 versus preoperative values), and minimum pHa 7.22 +/- 0.08 (P < 0.0001). One tension pneumothorax occurred during OLV. Immediate postoperative extubation was performed in 25 of 26 cases, reintubation was necessary in two cases. One patient with coronary artery disease died 36 h after surgery. Hypercapnia (maximum PaCO2 49 +/- 8 mm Hg, minimum pHa 7.37 +/- 0.04, P < 0.01) was still observed 48 h after surgery. These results demonstrate that adequate oxygenation can be preserved during OLV for VRS, but CO2 elimination is impaired. However, intraoperative hypercapnia and immediate postoperative tracheal extubation are well tolerated.

Optimizing selection of patients for major lung resection

OBJECTIVES

It is not known whether a normal diffusing capacity for carbon monoxide permits safe lung resection in patients with marginal spirometric values, or whether normal spirometric values negate the adverse effects of a low diffusing capacity. The purposes of this study were (1) to determine the best predictors of morbidity and mortality and (2) to assess whether interactions exist between diffusing capacity and spirometry that help estimate outcome after major lung resection.

DESIGN

A retrospective analysis of 376 patients who underwent lung resection was performed. Three hundred three had lung cancer and 73 had other disease. Two hundred eighty-four underwent lobectomy/bilobectomy and 92 had pneumonectomy. We assessed the relationship of 23 preoperative variables to 18 postoperative events classified into categories as pulmonary or cardiac complications, overall morbidity, and operative mortality.

RESULTS

The best single predictor of complications was the percent predicted postoperative diffusing capacity. The incidences of pulmonary and cardiac complications, morbidity, and mortality were inversely related to predicted postoperative diffusing capacity percent (p < 0.004 for each). Multivariate logistic regression analyses identified only predicted postoperative diffusing capacity percent and age as significant independent predictors of pulmonary complications, morbidity, and death, and these with prior myocardial infarction predicted cardiac complications. There were no interactions between percent predicted postoperative forced expiratory volume in 1 second and predicted postoperative diffusing capacity percent in estimating risks of complications.

CONCLUSION

Predicted postoperative diffusing capacity percent is the strongest single predictor of risk of complications and mortality after lung resection. There is little interrelationship of predicted postoperative diffusing capacity percent and predicted postoperative forced expiratory volume in 1 second, indicating that these values should be assessed independently in estimating operative risk.

The superiority of exercise testing over spirometry in the evaluation of postoperative lung function for patients with pulmonary disease

Thoracic surgeons have often been embarrassed by the discrepancy between an improvement in symptoms and the unchanged or even worse results of spirometry in postoperative patients with either bullae or inflammatory lung disease. Forty-four patients with lung diseases, who underwent a total of 47 operations, were categorized as follows: 12 cases of empyema, 16 cases of giant bulla (undergoing surgery a total of 19 times), 4 cases of bronchiectasis, and 12 cases of other miscellaneous diseases. All patients were tested preoperatively and again 4-6 months after surgery on both the spirometer and treadmill exercise tests. The forced vital capacity (FVC) and forced expiratory volume (FEV1.0) results were as follows: the empyema group 1.82 +/- 0.52 liters preoperatively to 1.93 +/- 0.69 liters postoperatively and 1.47 +/- 0.44 liters to 1.56 +/- 0.53 liters, respectively; and the giant bulla group, 3.49 +/- 0.96 liters to 3.35 +/- 0.77 liters and 2.35 +/- 0.96 liters to 2.48 +/- 0.69 liters, respectively. However, the exercise time was prolonged in the empyema group from 6.00 +/- 3.77 min to 8.33 +/- 3.80 min (P < 0.01) and in the giant bulla group from 11.83 +/- 3.71 min to 12.92 +/- 2.84 min (P < 0.05). It was thus concluded that exercise testing should be chosen for the postoperative evaluation of patients with inflammatory pulmonary disease and giant bullae, especially if any discrepancies are seen between spirometry and performance status, because on the basis of our results, it appears that the benefits obtained by surgery are best measured by the dynamic values of exercise testing and not by the static values of spirometry at rest.

Cardiopulmonary function after pulmonary lobectomy in patients with lung cancer

The effects of pulmonary lobectomy on cardiopulmonary function were investigated in 9 patients with lung cancer. Hemodynamic studies at rest and during exercise were performed before and 4 to 6 months after the operation. Differences in hemodynamics between before and after operation were observed with respect to heart rate, pulmonary arterial pressure, pulmonary vascular resistance index, and stroke volume index. Heart rate, pulmonary arterial pressure, and pulmonary vascular resistance index were significantly increased after operation, whereas stroke volume index was significantly decreased. It is thought that cardiac index was preserved by the increase in heart rate despite a decrease in stroke volume index associated with the decreased pulmonary vascular bed after the operation. When driving pressure and cardiac index were studied after operation, the pressure at rest and during exercise was higher, and the pressure-flow curve increased more steeply, as compared with the preoperative values. These results suggest a significant deterioration in cardiopulmonary function after lobectomy. As the patient characteristics were heterogeneous (five lobectomies and four bilobectomies), and their findings are limited, additional studies may be necessary in the future.

Postpneumonectomy pulmonary edema. A retrospective analysis of associated variables

STUDY OBJECTIVE

Evaluate the correlation between intravenous fluid administration and postpneumonectomy pulmonary edema.

DESIGN

Retrospective chart review.

SETTING

Large multispecialty group practice hospital.

PATIENTS

Adults who had a pneumonectomy performed between 1977 and 1988.

MEASUREMENTS AND RESULTS

Patients were identified who had postpneumonectomy pulmonary edema (PPE). Fluid administration and fluid balance information was found in records and compared with age- and sex-matched control patients who did not develop PPE. The side of pneumonectomy was noted for patients in each group. Autopsy findings were recorded for patients who died. Twenty-one patients met PPE criteria. No significant difference was found between groups for fluid administration or fluid balance. Patients who had right pneumonectomy had a significantly higher incidence of PPE. Patients with PPE had a 100 percent mortality rate and histologic evidence of the adult respiratory distress syndrome (ARDS) at autopsy.

CONCLUSIONS

PPE is caused by noncardiogenic pulmonary edema rather than excess intravenous fluid administration. There is a greater incidence of the syndrome with right pneumonectomy for unknown reasons. The mortality rate is high despite interventions for ARDS.