Spontaneous pneumothorax: marker gas technique for predicting outcome of manual aspiration

Expert Review on Spontaneous Pneumothorax: Advances, Controversies, and New Directions

For decades, there has been scanty evidence, most of which is of poor quality, to guide clinicians in the assessment and management of pneumothorax. A recent surge in pneumothorax research has begun to address controversies surrounding the topic and change the face of pneumothorax management. In this article, we review controversies concerning the etiology, pathogenesis, and classification of pneumothorax, and discuss recent advances in its management, including conservative and ambulatory management. We review the evidence base for the challenges of managing pneumothorax, including persistent air leak, and suggest new directions for future research that can help provide patient-centered, evidence-based management for this challenging cohort of patients.

Outpatient management of primary spontaneous pneumothorax

The outpatient management of primary spontaneous pneumothorax (PSP) is still debated. The risk of a tension pneumothorax is used to justify active treatment like chest-tube drainage, although outpatient management can reduce both the time in hospital and the cost of treatment. It is also likely to be the patient's choice. This report is a reappraisal of the situations for which outpatient management, by monitoring alone, or using minimally invasive techniques, can be considered.

Simple aspiration versus chest-tube insertion in the management of primary spontaneous pneumothorax: a systematic review

BACKGROUND

The initial treatment of a primary spontaneous pneumothorax (PSP) is controversial. Guidelines of the British Thoracic Society recommend simple aspiration for all PSP requiring intervention. The placement of chest tubes is only advocated for patients who fail simple aspiration. However, the American College of Chest Physicians Delphi Consensus Statement found simple aspiration to be rarely appropriate in the management of PSP.

AIMS

To compare simple aspiration with chest-tube drainage in the initial management of PSP.

METHODS

Meta-analysis of randomized controlled trials (RCTs).

OUTCOME MEASURES

Reductions in duration of hospital stay, recurrence rate and pain or dyspnoea score were classified as benefits, whereas reductions in successful events were classified as risks.

DATA COLLECTION AND ANALYSIS

For dichotomous data, the relative risk (RR) and 95% confidence intervals were calculated. For continuous data, weighted mean differences (WMD) were used.

RESULTS

Three RCTs were identified with a combined total of 194 patients. Simple aspiration was associated with shorter hospitalization (WMD -1.30 days [-2.20 to -0.39]). The results for success rate could not be combined because of differences in outcome definitions. However, a pooled result for "success at 1 week or more" showed no significant difference between either intervention (RR 0.86 [0.67, 1.11]). Results of recurrence at 1 year were also not significantly different (RR 0.73 [0.39-1.38]). Different reporting systems for pain scores meant that data could not be pooled. Only one trial reported dyspnoea scores.

CONCLUSION

RCT evidence in this field is limited, and the total sample size is too small to make any firm conclusion. On the basis of current available evidence, simple aspiration is advantageous in the initial management of PSP because of shorter hospitalization. There is no significant difference in recurrence at 1 year using either modality, and the efficacy data are inconclusive.

Manual aspiration versus chest tube drainage in first episodes of primary spontaneous pneumothorax: a multicenter, prospective, randomized pilot study

Although there is no agreement on the optimal treatment of patients presenting with a first episode of primary spontaneous pneumothorax, the majority of physicians prefer chest tube drainage for air evacuation. Manual aspiration of air has been proposed by some, but lack of sound comparative data and safety data has limited its use. In this first randomized, prospective, multicenter pilot study, 60 patients with a first episode of primary spontaneous pneumothorax were randomly allocated to manual aspiration (n = 27) or chest tube drainage (n = 33). Immediate success was obtained in 16 out of 27 (59.3%) in the manual aspiration group, and in 21 out of 33 (63.6%) in the chest tube drainage group (p = 0.9). One-week success rates were 25 out of 27 (93%) in the intention-to-treat manual aspiration group and 28 out of 33 (85%) in the chest tube drainage group (p = 0.4). Fourteen of 27 manual aspiration patients (52%) were hospitalized, versus 100% of the chest tube drainage patients (p < 0.0001). Recurrence rates with at least 1-year follow-up were 7 out of 26 (26%) in the manual aspiration group, and 9 out of 33 (27.3%) in the chest tube drainage group (p = 0.9). There were no complications associated with manual aspiration. Although statistical power is insufficient to formally confirm therapeutic equality, this pilot study suggests that in first episodes of primary spontaneous pneumothorax, manual aspiration seems equally effective as chest tube drainage and is safe, well tolerated, and feasible as an outpatient procedure in the majority of patients.

Management of spontaneous pneumothorax: are British Thoracic Society guidelines being followed?

In 1993, the British Thoracic Society (BTS) issued guidelines for the management of spontaneous pneumothorax. The aim of this study was to determine the level of adherence to and awareness of these guidelines at a London teaching hospital. A retrospective case note audit of 59 episodes of acute spontaneous pneumothorax was performed. In patients undergoing intervention, the initial procedure was simple aspiration in 32 (73%) and chest tube insertion in 12 (27%) cases, contrasting with the BTS recommendation that aspiration should be attempted first in all such patients. Simple aspiration was successful on 34% of occasions. Successful aspiration was associated with a significantly shorter hospital stay (median 3, range 1-11 days) than either failed aspiration (7, 3-66 days; p=0.003) or chest tube insertion without aspiration (9, 3-16 days; p=0.005). Other areas where practice differed from the BTS guidelines were clamping of chest tubes and use of a pursestring suture for wound closure. A follow up questionnaire survey suggested a lack of familiarity with the guidelines. These findings indicate that current management of spontaneous pneumothorax deviates from the BTS guidelines in a number of potentially important respects. Attention should be directed to improving awareness of and access to clinical guidelines.

Bedside tracer gas technique accurately predicts outcome in aspiration of spontaneous pneumothorax

BACKGROUND

There is no technique in general use that reliably predicts the outcome of manual aspiration of spontaneous pneumothorax. We have hypothesised that the absence of a pleural leak at the time of aspiration will identify a group of patients in whom immediate discharge is unlikely to be complicated by early lung re-collapse and have tested this hypothesis by using a simple bedside tracer gas technique.

METHODS

Eighty four episodes of primary spontaneous pneumothorax and 35 episodes of secondary spontaneous pneumothorax were studied prospectively. Patients breathed air containing a tracer (propellant gas from a pressurised metered dose inhaler) while the pneumothorax was aspirated percutaneously. Tracer gas in the aspirate was detected at the bedside using a portable flame ioniser and episodes were categorised as tracer gas positive (>1 part per million of tracer gas) or negative. The presence of tracer gas was taken to imply a persistent pleural leak. Failure of manual aspiration and the need for a further intervention was based on chest radiographic appearances showing either failure of the lung to re-expand or re-collapse following initial re-expansion.

RESULTS

A negative tracer gas test alone implied that manual aspiration would be successful in the treatment of 93% of episodes of primary spontaneous pneumothorax (p<0.001) and in 86% of episodes of secondary spontaneous pneumothorax (p=0.01). A positive test implied that manual aspiration would either fail to re-expand the lung or that early re-collapse would occur despite initial re-expansion in 66% of episodes of primary spontaneous pneumothorax and 71% of episodes of secondary spontaneous pneumothorax. Lung re-inflation on the chest radiograph taken immediately after aspiration was a poor predictor of successful aspiration, with lung re-collapse occurring in 34% of episodes by the following day such that a further intervention was required.

CONCLUSIONS

National guidelines currently recommend immediate discharge of patients with primary spontaneous pneumothorax based primarily on the outcome of the post-aspiration chest radiograph which we have shown to be a poor predictor of early lung re-collapse. Using a simple bedside test in combination with the post-aspiration chest radiograph, we can predict with high accuracy the success of aspiration in achieving sustained lung re-inflation, thereby identifying patients with primary spontaneous pneumothorax who can be safely and immediately discharged home and those who should be observed overnight because of a significant risk of re-collapse, with an estimated re-admission rate of 1%.

Bedside tracer gas technique accurately predicts outcome in aspiration of spontaneous pneumothorax

BACKGROUND

There is no technique in general use that reliably predicts the outcome of manual aspiration of spontaneous pneumothorax. We have hypothesised that the absence of a pleural leak at the time of aspiration will identify a group of patients in whom immediate discharge is unlikely to be complicated by early lung re-collapse and have tested this hypothesis by using a simple bedside tracer gas technique.

METHODS

Eighty four episodes of primary spontaneous pneumothorax and 35 episodes of secondary spontaneous pneumothorax were studied prospectively. Patients breathed air containing a tracer (propellant gas from a pressurised metered dose inhaler) while the pneumothorax was aspirated percutaneously. Tracer gas in the aspirate was detected at the bedside using a portable flame ioniser and episodes were categorised as tracer gas positive (>1 part per million of tracer gas) or negative. The presence of tracer gas was taken to imply a persistent pleural leak. Failure of manual aspiration and the need for a further intervention was based on chest radiographic appearances showing either failure of the lung to re-expand or re-collapse following initial re-expansion.

RESULTS

A negative tracer gas test alone implied that manual aspiration would be successful in the treatment of 93% of episodes of primary spontaneous pneumothorax (p<0.001) and in 86% of episodes of secondary spontaneous pneumothorax (p=0.01). A positive test implied that manual aspiration would either fail to re-expand the lung or that early re-collapse would occur despite initial re-expansion in 66% of episodes of primary spontaneous pneumothorax and 71% of episodes of secondary spontaneous pneumothorax. Lung re-inflation on the chest radiograph taken immediately after aspiration was a poor predictor of successful aspiration, with lung re-collapse occurring in 34% of episodes by the following day such that a further intervention was required.

CONCLUSIONS

National guidelines currently recommend immediate discharge of patients with primary spontaneous pneumothorax based primarily on the outcome of the post-aspiration chest radiograph which we have shown to be a poor predictor of early lung re-collapse. Using a simple bedside test in combination with the post-aspiration chest radiograph, we can predict with high accuracy the success of aspiration in achieving sustained lung re-inflation, thereby identifying patients with primary spontaneous pneumothorax who can be safely and immediately discharged home and those who should be observed overnight because of a significant risk of re-collapse, with an estimated re-admission rate of 1%.

Spontaneous pneumothorax. Comparison of thoracic drainage vs immediate or delayed needle aspiration

In the first part of this study, 61 patients admitted for the first episode or the first recurrence of a spontaneous pneumothorax (SP) were randomly treated with thoracic drainage (TD; 28 patients) or with simple needle aspiration (NA; 33 patients). Success rate of therapy was significantly higher with TD than with NA (93%, CI 84 to 100 vs 67%, CI 51 to 83; p = 0.01). Hospital stay was similar between the two groups (7 +/- 4.6 vs 7 +/- 5.6 days), mainly because NA was delayed by 72 h in 26 patients. Recurrence rates at 3 months were 29% (CI 11 to 47%) after TD, and 14% (CI 0 to 29%) after NA (p > 0.20, NS). In the second part of the study, an additional population of 35 patients was treated by immediate NA, with a success rate of 68.5% (CI 53.5 to 83.5%), and a recurrence rate at 3 months of 30% (CI 10 to 50%). Taken together, our results indicate that NA may be proposed as a first-line treatment of SP, with a successful result in two thirds of patients and recurrence in one fifth of patients. In patients who do not heal with NA, a combined risk of TD failure and short-term recurrence of 50% may be an incentive for undelayed surgical procedures.

Evaluation of conventional chest tube therapy for iatrogenic pneumothorax

STUDY OBJECTIVE

To assess conventional, large chest tube therapy in iatrogenic pneumothorax and to determine the optimal moment when to use more invasive procedures.

DESIGN

Retrospective chart review.

SETTING

Medical intensive care unit of a university hospital.

PATIENTS

Forty-seven patients with needle-induced iatrogenic pneumothorax. Twenty-four patients had an underlying pleural or pulmonary disorder.

INTERVENTIONS

After insertion of a 20- to 24-French plastic chest tube connected to an underwater seal, suction was maintained until gas egress stopped or up to 10 days in patients with a persisting gas leak.

RESULTS

In 96 percent, a definite occlusion of the pneumothorax was achieved. In all patients without an underlying lung disorder, gas egress stopped definitely after 72 h. In the presence of an underlying lung disorder, 92 percent of the pneumothoraces were healed after 10 days of continuous suction therapy. At 72 h, only 71 percent of the latter group were healed (p < 0.05 vs patients without lung disease). No major complication of chest tube therapy occurred.

CONCLUSION

Conventional chest tube therapy is a safe and effective treatment for iatrogenic pneumothorax. In patients with an underlying lung disease, gas egress may last for up to 10 days. In these patients, the earlier use of a more invasive approach may be justified if the air leak persists.