Pneumothorax is defined as the presence of air in the pleural space, and can be acquired (iatrogenic and traumatic) or spontaneous, depending on its etiology. These categories are, in turn, divided into primary (no obvious cause), secondary (underlying pleuropulmonary disease as an obvious cause), and catamenial (associated with the menstrual cycle).

It is difficult to determine the real extent of the incidence of primary spontaneous pneumothorax, although figures in the literature suggest that the incidence is 16.7/100,000 per year in men and 5.8/100,000 per year in women, according to Gupta et al.,1 or 7.4–18/100,000 per year (adjusted for age) in men and 1.2–6/100,000 per year (adjusted for age) in women, according to Noppen and De Keukeleire.2

The initial treatment of the first episode of primary spontaneous pneumothorax ranges from observation3,4 to surgery.5,6 However, in cases of large pneumothorax or unstable patients, the clinical practice guidelines recommend active ambulatory treatment.7 Needle aspiration and the use of external devices such as minichest tubes or Heimlich valves offer greater advantages in terms of avoiding admissions without increasing recurrence.7–10. In spite of this, other guidelines do not include this approach as the first line of treatment,11 and in other studies needle aspiration is presented as a therapeutic strategy with low adherence.12,13

Our aim in this study was to demonstrate the advantages of digital needle aspiration (by reducing the human factor of aspiration) versus standard manual aspiration in order to improve acceptance and increase the uptake of this strategy.

Over a period of 38 months (November 16, 2011 to January 7, 2015), 72 patients with a first episode of primary spontaneous pneumothorax were initially included as potential candidates for randomization. After the exclusion criteria were checked, 5 were excluded and the remaining 67 were included in the study. Of these, 36 were assigned to the control group and 31 to the intervention group. Fig. 1 shows how patients included in the study were recruited and randomized.

Fig. 1.

Recruitment and randomization process.

(0.31MB).

No patients were lost to follow-up. Seven months after study inclusion was complete, all patients were contacted to verify their status, so the follow-up range is between 7 and 45 months.

The characteristics presented by patients in both groups (Table 1) were analyzed first, and it was determined that they do not differ in age, sex, pneumothorax side, body mass index (BMI), smoking habit, or pack-year index, as expected in an RCT. These data revealed that the typical patient in our study was a young male, smoker or former smoker, with a right pneumothorax. Indeed, this pattern coincides with the typical patient with spontaneous idiopathic pneumothorax.

Secondly, the main study variables were analyzed (Table 2). Resolution with ambulatory management was observed in 58% of the patients, distributed equally among both groups. Neither the recurrence rate, readmission rate, nor days of admission show statistically significant differences between the groups. Need for surgery was indicated according to the criteria normally used in the hospital for primary spontaneous pneumothorax (recurrence, prolonged air leak > 5 days, at-risk professions). Of the 18 patients who underwent surgery, 12 were for ipsilateral recurrence and 6 for prolonged air leak. Surgical procedures included bullectomy with abrasion on 14 occasions and bullectomy with pleurectomy on 4 occasions. Postoperative recurrence rate was 5.5% (1 case).

Fig. 2 describes the management of randomized study patients.

Fig. 2.

Management of randomized patients.

(0.24MB).

An analysis of recurrences during follow-up was also performed using the Kaplan-Meier test. Fig. 3 shows that the patterns of both graphs are similar throughout the follow-up period.

Fig. 3.

Kaplan-Meier analysis of recurrences during follow-up.

(0.06MB).

The absolute risk of success or resolution of the episode without admission in the digital aspiration group in our study was 58%. With our sample size, this means that with a 95% confidence interval the success of this technique can be estimated at between 34% and 91%.

The study was not designed as a non-inferiority study, but had we performed such an analysis we would have had to establish a minimum value in order to consider the technique successful. We could assume success to mean that in one-third of patients with primary spontaneous pneumothorax the condition is resolved without admission, as occurred in our retrospective cohort study. Based on this assumption, taking the lowest value of the confidence interval for digital aspiration (34%) we would be above the minimum value, so in a no-difference study, digital aspiration would be at least as effective as manual aspiration.

An anonymous satisfaction survey was conducted among emergency department staff who performed the needle aspiration. Twenty professionals answered the question of how many aspirations they performed each year and whether they felt more comfortable with the manual or digital aspiration. A total of 80% of professionals preferred the digital method, and all professionals who performed more than 5 aspirations/year (8 emergency doctors) chose this option.

Studies are regularly published on the initial treatment of primary spontaneous pneumothorax, indicating its importance. Treatments for a first episode range from simple observation, ambulatory management with needle aspiration or Heimlich valves, to hospital management with chest drains and surgical intervention.3–11

In most published papers, observation is reserved for stable patients with pneumothorax involving a lung collapse of less than 20%. However, some studies question whether pneumothorax size should be the criterion for deciding whether patients with pneumothorax should be observed or treated.4

If active treatment has been decided, it seems clear that there is no difference in recurrences or readmissions between placing a chest tube and admitting a patient and performing ambulatory needle aspiration, while the use of needle aspiration could prevent two-thirds of admissions, as demonstrated by two systematic reviews.10–15 Another clinical trial with 56 randomized patients subsequently showed very similar results, confirming that needle aspiration does not increase recurrence rates.16 Unlike other clinical trials, this study recruited patients with traumatic pneumothorax, and this variable was an independent factor for good prognosis at resolution. Female gender was also seen to be an independent factor, with women showing better resolution data than men.

Even with all the scientific tests available, needle aspiration is rarely undertaken as the first step in the management of pneumothorax in many countries,12,13 and few emergency departments perform it in Spain. The low reliance on evidence in this setting may be a criticism of the small number of patients enrolled in clinical trials. In fact, the systematic review only retrieved 331 patients from 4 clinical trials.10 However other trials have continued to corroborate these results,16 and the lack of evidence supporting an approach other than ambulatory management leads us to think that other factors prevent the implementation of a needle aspiration strategy in hospitals.

The lack of strict protocols means that needle aspiration is less used. A retrospective cohort study conducted by our group found that hospital admissions could have been avoided in twice as many patients if needle aspiration had been part of routine clinical practice.17 The human factor was also identified as one of the possible reasons for this reduced uptake, along with the absence of protocols.

In contrast, in the same hospital with the same emergency department staff, after the AMVADI study has been designed, the decrease in admissions as a result of needle aspiration was the same as that reported in other published papers. In this study, 58% of patients who underwent needle aspiration (manual or digital) were managed in an ambulatory setting without admission.

The clinical trial failed to demonstrate that eliminating the human factor from aspiration and performing it with a digital device further reduces admissions. If we were to apply a non-inferiority principle, the digital system would have been shown to be not inferior to the manual intervention, with a 95% confidence interval of 31%–91%. In our study both options reduced admissions by 58%, in line with published literature.10–15 Pneumothorax recurrence data after 7–45 months’ follow-up show reasonable figures ranging from 19% in the digital aspiration group to 22% in the manual aspiration group.

The limitations of these data must be taken into account: for example, a larger sample size might provide smaller confidence intervals and even reach statistical significance in some of the results. The fact that this is a practical study performed in a single center could make it difficult to extrapolate results to clinical practice. However, in centers where manual needle aspiration is already performed, transition to a digital system should not be a problem if nurses were given a short training course (15−20 min clinical session). The different aspiration techniques of the 2 methods makes it difficult to select the same volume/time criteria for both. However, manual aspiration of up to 3500 cc is the standard volume used in different RCTs17 and wall suction in pneumothorax was performed at ↓10 cmH2O for 30 min maximum. We also believe that the different protocols do not alter the outcome, as patients with intact pleura are resolved with both protocols, and if the pleura is not intact, the problem will not be resolved with either protocol.

The digital system is increasingly used as a support technique in thoracic surgery departments. It has proven to be beneficial and convenient for both patients and caregivers. In 1 paper, 15 staff members of the thoracic surgery department in a hospital in Birmingham were asked for feedback on the convenience of using the digital system in patients with diverse surgical conditions; 67% rated it as very good or excellent.18 Similarly, a survey conducted in the emergency department found that 80% of respondents prefer to use the digital system in routine practice. Among the group of respondents, all physicians performing needle aspiration procedures more than 5 times a year prefer the digital system. Other studies confirm that these systems are useful in the management of pneumothorax in different phases.19 Based on these results, we believe that digital aspiration may facilitate the applicability of this strategy.

Cost-effectiveness studies show that the implementation of this strategy is of the utmost importance. In a study of 60 consecutive patients with pneumothorax, 48 were aspirated with a pigtail drain, resulting in an estimated reduction in hospitalization costs of 114,000 euros.20 The economic impact of needle aspiration in England has been analyzed, and estimates show that not performing aspiration in 10% of patients costs the English national health system more than £438,412 per year. The authors also found that application of the ACCP protocol (drainage and admission without needle aspiration) in England would entail an additional annual cost of £3.9 million.21

In conclusion, we believe that digital aspiration systems can be an effective alternative and that this approach increases user satisfaction. This could facilitate the expansion and wider implementation of the technique.

The authors state that they have no conflict of interests.