Discussion
This is the first study to our knowledge that specifically explores the effect of different pleural procedures on PROMs, including outcomes of importance to patients. As the treatment intent in many such procedures is symptom amelioration, provision of validated data on the symptom effect of such interventions is required to provide rational care for patients. Our findings identified a correlation between fluid removal and improvement in patients’ dyspnoea and a novel predictor of symptomatic response (septation score).
The results demonstrate a number of key findings that should be useful in the future management of patients with pleural effusion due to undergo intervention. The majority of patients (108/126, 85.7%) experience symptom benefit from drainage and reported improvement in terms of breathlessness (on the Likert scale). However, even where specialist clinicians have selected patients for procedures thought to be of potential benefit, 14.3% of patients undergoing therapeutic aspiration did not experience a worthwhile change in breathlessness. These are important data when consenting patients for such procedures and may justify conducting a therapeutic aspiration in all patients prior to offering definitive treatment. Pleural procedures are associated with potential significant harm, and being able to predict which patients will not gain symptom relief would be of great value.17
Of those with a poor symptomatic response, 71% had either trapped lung or <550 mL of fluid drained due to cough or chest tightness as a result of fluid removal. For the remaining 29%, we assume these patients had other, parallel reasons for breathlessness, with fluid being a minor contributor to symptoms. However, the average fluid drained in patients with a lack of meaningful symptomatic response was 836 mL, enforcing the idea that volume of drainage alone and therefore size of effusion may not always be related to symptom benefit.
Our results provide potentially important information on a novel predictor of symptomatic response that is available prior to drainage. The septation score at preprocedure US was inversely associated with symptomatic benefit from drainage. Although this effect may be assumed to be related to the amount of fluid drained (as more septated effusions may lead to less drainage of fluid), multivariate analysis suggests that the septation score is independently predictive of symptom change when accounting for volume of fluid. The mechanism of this effect is not completely clear, and we speculate that the septations correlate with reduced fluid drainage, but may also act as a marker for another intrathoracic process (such as visceral pleural thickening or more advanced disease), which may be the reason behind poorer symptomatic response. If replicated in future studies, this may be an important factor available prior to any drainage procedure that allows prediction of poor symptomatic response.
Most clinicians would consent patients undergoing pleural procedures for the procedure being painful, but precise data on the pain associated with such procedures have not until now been available. The pain data in this study are highly informative in this regard, but also demonstrate some surprising results. Medical thoracoscopy without poudrage, for example, was not significantly different in terms of pain to standard ICD insertion. This lack of difference may reflect the use of increased doses of anaesthetic and sedation in thoracoscopy patients, but does provide reassurance for patients. Talc poudrage has here been associated with a doubling in pain levels (11.5 vs 26.8 mm) and this again provides important information in obtaining patient consent and the provision of adequate analgesia post procedure. In our centre, intravenous opiates were not given to the patients prior to thoracoscopy and baseline pain levels prior to the procedure were not assessed in our study.
One particularly interesting finding which should influence current practice is the relative pain experienced in those undergoing diagnostic aspiration. Pain experienced was no different comparing diagnostic aspiration using a 21G needle (outer diameter 0.82 mm) and therapeutic aspiration using 6F catheters (outer diameter 3 mm) despite the use of similar doses of local anaesthetic in our practice. This suggests that local anaesthesia should be used even in diagnostic procedures in all cases.
There are limitations to this work. Patients were assessed from one hospital which is a tertiary referral centre for pleural disease. This study only assessed symptom change at 1 hour post procedure for day-case procedures, and 24 hours for inpatients, and potentially longer-term studies are required to follow-up this work. Potentially, an amnesic effect from slight sedation could affect patients’ responses but the exact extent of the effect is difficult to assess. Lastly, there is a potentially significant number of confounding factors that contribute to PROMs which are difficult to assess in our data set (eg, prior drainages, different diagnosis). A larger multicentre, multinational study is needed to confirm our results in the future.
This study is the first to prospectively address PROMs in pleural interventions in real-life practice. The outcomes defined in our data set have the potential to be employed in everyday clinical practice and may form the basis of a clinically useful tool in the future to appraise the effect, compare the efficiency and identify the importance of pleural interventions to the patients.