Clare M. Laroche

Comparison of shuttle walk with measured peak oxygen consumption in patients with operable lung cancer

Background: The relationship between the shuttle walk test and peak oxygen consumption in patients with lung cancer has not previously been reported. A study was undertaken to examine this relationship in patients referred for lung cancer surgery to test the hypothesis that the shuttle walk test would be useful in this clinical setting. Methods: 125 consecutive patients with potentially operable lung cancer were prospectively recruited. Each performed same day shuttle walking and treadmill walking tests. Results: Shuttle walk distances ranged from 104 m to 1020 m and peak oxygen consumption ranged from 9 to 35 ml/kg/min. The shuttle walk distance significantly correlated with peak oxygen consumption (r = 0.67, p<0.001). All 55 patients who achieved more than 400 m on the shuttle test had a peak oxygen consumption of at least 15 ml/kg/min. Seventy of 125 patients failed to achieve 400 m on the shuttle walk test; in 22 of these the peak oxygen consumption was less than 15 ml/kg/min. Nine of 17 patients who achieved less than 250 m had a peak oxygen consumption of more than 15 ml/kg/min. Conclusion: The shuttle walk is a useful exercise test to assess potentially operable lung cancer patients with borderline lung function. However, it tends to underestimate exercise capacity at the lower range compared with peak oxygen consumption. Our data suggest that patients achieving 400 m on the shuttle walk test do not require formal measurement of oxygen consumption. In patients failing to achieve this distance we recommend assessment of peak oxygen consumption, particularly in those unable to walk 250 m, because a considerable proportion would still qualify for surgery as they had an acceptable peak oxygen consumption.

Cardiopulmonary exercise tests and lung cancer surgical outcome

STUDY OBJECTIVES Surgical resection remains the treatment of choice for anatomically resectable non-small cell lung cancer. However, the presence of associated comorbid conditions increases the risk of death and surgical complications. Several studies have evaluated the usefulness of preoperative exercise testing for predicting postoperative morbidity and mortality. The aim of this study was to establish whether exercise testing could predict poor surgical outcome in lung cancer surgery and whether the absolute value or percentage of predicted value is the better predictor of the surgical outcome. DESIGN The study was designed as a prospective study. PATIENTS AND SETTING One hundred thirty patients with potentially operable lung cancer at Papworth Hospital over 2 years were recruited; of these, 101 underwent curative surgery. INTERVENTIONS Spirometry and cardiopulmonary exercise tests were performed for every patient (n = 99), except for two patients with back problems. We also recorded the outcome of surgery, in particular, complications and mortality. MEASUREMENTS AND RESULTS Mean maximum oxygen transport at peak exercise (Vo(2)peak) was 18.3 mL/kg/min (SD, 4.7 mL/kg/min), and mean percentage of predicted Vo(2)peak value was 84.4% (SD, 30%). Poor surgical outcome was significantly related to Vo(2)peak percentage of predicted (p < 0.01) but not to the actual oxygen uptake value. CONCLUSIONS The use of the percentage of predicted Vo(2)peak value would be a better indicator of surgical outcome, since it predicts the surgical outcome better, and corrects for normal physiologic ranges. The threshold of Vo(2)peak for surgical intervention could be set between 50% and 60% of predicted without excess surgical mortality.

Effect of lung cancer surgery on quality of life

Background: Health related quality of life (HRQOL) after surgery is important, although very limited data are available on the QOL after lung cancer surgery. Methods: The effect of surgery on HRQOL was assessed in a prospective study of 110 patients undergoing potentially curative lung cancer surgery at Papworth Hospital, 30% of whom had borderline lung function as judged by forced expiratory volume in 1 second. All patients completed the EORTC QLQ-C30 and LC13 lung cancer module before surgery and again at 1, 3 and 6 months postoperatively. Results: On average, patients had high levels of functioning and low levels of symptoms. Global QOL had deteriorated significantly 1 month after surgery (p = 0.001) but had returned to preoperative levels by 3 months (p = 0.93). Symptoms had worsened significantly at 1 month after surgery but had returned to baseline levels by 6 months. Low values on the preoperative HRQOL scales were not significantly associated with poor surgical outcome. However, patients with low preoperative HRQOL functioning scales and high preoperative symptom scores were more likely to have poor postoperative (6 months) QOL. The only lung function measurement to show a marginally statistically significant association with quality of life at 6 months after surgery was percentage predicted carbon monoxide transfer factor (Tlco). Conclusion: Although surgery had short term negative effects on quality of life, by 6 months HRQOL had returned to preoperative values. Patients with low HRQOL functioning scales, high preoperative symptom scores, and preoperative percentage predicted Tlco may be associated with worse postoperative HRQOL.

Role of computed tomographic scanning of the thorax prior to bronchoscopy in the investigation of suspected lung cancer

BACKGROUND Fibreoptic bronchoscopy (FOB) is the usual initial investigation of choice in patients with suspected endobronchial carcinoma, but it is often non-diagnostic. Once a positive diagnosis has been made, many patients undergo staging by computed tomographic (CT) scanning to assess the extent of the disease and its suitability for radical treatment. To determine whether initial CT scanning before FOB is a cost effective way of reducing subsequent unnecessary or unhelpful invasive diagnostic procedures, a study was undertaken in 171 patients with suspected endobronchial carcinoma. METHODS A randomised two group study was performed with all patients undergoing an initial CT staging scan. In group A the CT scans were reviewed before FOB, allowing cancellation or a change to an alternative invasive procedure if considered appropriate. In group B all patients proceeded to FOB with the bronchoscopist blinded to the result of the CT scan until after the procedure. RESULTS In group A six of 90 patients (7%) required no further investigations as the CT scan was either normal, consistent with benign disease, or consistent with widespread metastatic disease. Of the remainder, bronchoscopy was diagnostic in 50 of 68 (73%) in group A compared with 44 of 81 (54%) in group B (p = 0.015). Overall, a positive diagnosis was made after a single invasive investigation in 64 of 84 patients (76%) in group A compared with only 45 of 81 patients (55%) in group B (p = 0.005). Only seven of 90 patients (8%) in group A required more than one invasive investigation compared with 15 of 81 patients (18.5%) in group B. In patients with malignancy, bronchoscopy was more likely to be diagnostic in group A (50 of 56 patients (89%)) than in group B (44 of 62 (71%); p = 0.012), and the diagnosis was more frequently made on the initial invasive investigation (group A, 63 of 70 (90%); group B, 44 of 62 (71%); p = 0.004). Because of the lower number of invasive procedures performed in group A than in group B, the cost of performing CT scans before FOB in all patients in group A would have equated to a projected cost of performing CT scans in 60% of patients after FOB in group B. CONCLUSIONS Performing initial CT thoracic scans before bronchoscopy in patients with suspected endobronchial malignancy is a cost effective way of improving diagnostic yield from invasive diagnostic procedures and occasionally may obviate the need for any further investigation.

Diaphragm strength in patients with recent hemidiaphragm paralysis.

Eleven patients with unilateral diaphragm paralysis of recent onset were studied to investigate the effect of the paralysis on inspiratory muscle function. Nine of the patients had noticed a decrease in exercise tolerance, which was not explained by any other pathological condition. Hemidiaphragm dysfunction was confirmed by the demonstration of a greatly reduced or absent transdiaphragmatic pressure on stimulation of the phrenic nerve in the neck, by means of surface bipolar electrodes (unilateral twitch Pdi), compared with normal values on the contralateral side. Transdiaphragmatic pressure was 44.6% (9.4%) predicted during a maximal sniff and 30.3% (16.8%) predicted during a maximal static inspiration against a closed airway, confirming diaphragm weakness. Maximum static inspiratory mouth pressures were also low (61.7% (12.7%) predicted), consistent with a reduction in inspiratory muscle capacity. Phrenic nerve conduction time was prolonged on the affected side in nine patients, consistent with phrenic nerve dysfunction, whereas on the unaffected side it was normal. It is concluded that recent hemidiaphragm paralysis causes a reduction in transdiaphragmatic pressure that is associated with a reduction in maximum inspiratory mouth pressure. Phrenic nerve stimulation is a useful technique with which to confirm and quantify hemidiaphragm dysfunction. Measurement of phrenic nerve conduction time provides useful information about the underlying pathology.

Ventilation-perfusion scintigraphy to predict postoperative pulmonary function in lung cancer patients undergoing pneumonectomy

OBJECTIVE The American College of Chest Physicians (ACCP) recommends using quantitative perfusion scintigraphy to predict postoperative lung function in lung cancer patients with borderline pulmonary function tests who will undergo pneumonectomy. However, previous scintigraphic data were gathered on small cohorts more than a decade ago, when surgical populations were significantly different with respect to age and sex compared with typical lung cancer patients undergoing pneumonectomy in 2005. We therefore revisited the use of V/Q scintigraphy in pneumonectomy patients in predicting postoperative pulmonary function and the appropriateness of current clinical guidelines. CONCLUSION Contrary to ACCP guidelines, we found that ventilation scintigraphy alone provided the best correlation between the predicted and actual postoperative values and recommend its use to predict postoperative lung function. However, scintigraphic techniques may underestimate postoperative lung function, so caution is required before unnecessarily preventing a patient from undergoing surgery that offers a potential cure.

Diaphragm weakness in Charcot-Marie-Tooth disease.

Two patients are described with Charcot-Marie-Tooth disease and chronic peripheral neuropathy. Both had dyspnoea, orthopnoea, and evidence of severe diaphragm weakness. Expiratory muscle function was well preserved and abnormalities of gas exchange during sleep were only minor.

Unsuspected myasthenia gravis presenting as respiratory failure.

A patient developed respiratory failure after surgical removal of a recurrent thymoma, which necessitated removal of part of the diaphragm. The respiratory failure was due to previously undiagnosed myasthenia gravis, which had selectively affected the respiratory muscles.

Respiratory muscle weakness in the Lambert-Eaton myasthenic syndrome.

Respiratory muscle function was assessed in six patients with the Lambert-Eaton myasthenic syndrome. Five had histologically proved small cell carcinoma of the lung; the sixth later developed metastases from an unknown primary site. Two patients had ventilatory failure, one without respiratory symptoms; another, who had emphysema, had dyspnoea and orthopnoea. The remaining three patients had no respiratory symptoms. Four patients had limb muscle weakness as judged by the maximal voluntary contraction of the quadriceps muscle (range for all subjects 32-100% predicted). Transdiaphragmatic pressure (Pdi) was measured during a maximal unoccluded sniff (Pdi: sniff), a maximal sustained inspiratory effort against a closed airway (Pdi: Pimax), and phrenic nerve stimulation (Pdi: twitch). Mild to moderate diaphragmatic weakness was present in all six patients in proportion to the degree of leg weakness (Pdi: sniff 30-64% predicted; r = 0.6; Pdi:Pimax 6-69% predicted, r = 0.8); this was associated with very low or absent Pdi:twitch during phrenic nerve stimulation. Four patients had weakness of the expiratory muscles. Improvement in muscle strength was documented in two patients after tumour chemotherapy and specific treatment with 3,4-diaminopyridine and prednisolone; one patient was still alive five years from first diagnosis. It is concluded that the respiratory muscles may be implicated in this condition more often than has previously been recognised. As the lack of mobility may cause respiratory symptoms to be minimised, the presence of respiratory muscle weakness may remain undiagnosed unless formal measurement of respiratory muscle function is made.

P129 Report of a respiratory health check in a self-selected group of male prisoners in Suffolk

Introduction A health bus sponsored by Pfizer Ltd was loaned to Suffolk PCT for a 2-week period in June 2011, for the purpose of health promotion in a range of Suffolk locations. During this period, two prisons were visited, each on one occasion only. At each prison, the Unit Manager allowed prisoners to attend for voluntary health checks. As part of this assessment, members of the Suffolk COPD nursing team carried out a respiratory-focused questionnaire and spirometry on each volunteer. Method Each prisoner was asked a series of specific questions concerning respiratory status, including past and present history of smoking tobacco and other substances, presence of current respiratory symptoms, history of known respiratory conditions and respiratory medications. The questionnaire was administered by a respiratory nurse consultant, while a trained respiratory nurse carried out spirometry. Results 136 prisoners underwent the respiratory health check. Age range was 19–55 years, average 33 years, median 31 years. 90 (66%) were current smokers (13% of whom had started smoking in prison), and a further 35 (26%) were ex-smokers. 85 (79% of current smokers and 40% of ex-smokers) had also smoked cannabis. Conclusions In 2008, smoking rates for England were reported to be around 21% of adults.1 This snapshot sample of two prisons in Suffolk is consistent with a higher prevalence of both current smoking (66%) and past smoking (26%) in prisoners, although the incidence may be artificially raised due to self selection for the health assessments. FEV1/FVC ratio tended to be lower among smokers compared to ex smokers and never smokers. A more comprehensive study of prisoners should be considered, to reduce the burden of smoking related disease within the prison service.Abstract P129 Table 1 Effect of smoking history in incidence of respiratory symptoms Respiratory symptoms Total Shortness of breath on exertion Cough Sputum Smokers 90 34 48 48 Ex-smokers 35 2 2 2Abstract P129 Table 2 Effect of smoking history on spirometry Spirometry FEV1/FVC ratio average FEV1/FVC ratio median Range Smokers 79% 81% 53–86 Ex-smokers 83% 84% 69–100 Non-smokers 90% 89% 86–100