Treatment of primary spontaneous pneumothorax in adults

INTRODUCTION — Gas in the pleural space is termed pneumothorax. Pneumothorax can be a life-threatening condition that needs prompt attention. The management strategies of primary spontaneous pneumothorax (PSP; presents in the absence of an external factor/underlying cause) and secondary spontaneous pneumothorax (SSP; presents as a complication of underlying lung disease) (table 1) differ in their management strategies.

The management of PSP is discussed in this topic review. The etiology and diagnosis of pneumothorax and the management of SSP are discussed separately. (See "Pneumothorax in adults: Epidemiology and etiology" and "Clinical presentation and diagnosis of pneumothorax" and "Treatment of secondary spontaneous pneumothorax in adults".)

INITIAL EVALUATION AND MANAGEMENT

General principles — Following the radiographic identification of PSP, clinicians should quickly estimate the stability of the patient and the symptom burden so that appropriate therapy can be initiated. The principle focus of PSP management is to relieve symptoms and stop the air leak rather than rapidly expanding the lung to achieve radiographic resolution (ie, "treating the chest radiograph"), which does not necessarily stop the air leak. The assessment of size, while reasonable, is now less important in determining a treatment strategy. Size assessment is discussed separately. (See "Clinical presentation and diagnosis of pneumothorax", section on 'Pneumothorax size'.)

The approach to managing PSP varies widely among institutions and across continents. Our approach expands upon that outlined in several published clinical consensus statements and guidelines from the American College of Chest Physicians (ACCP; 2001), the British Thoracic Society (BTS; 2023), the European Respiratory Society (2015), and the Japanese Association for Chest Surgery (2014) [1-4]. Our approach is one that prioritizes patient safety and symptom control, preferably with minimal intervention, to avoid associated pain and risks.

Symptom control — All patients with PSP should receive resuscitation with a focus on airway stabilization (if needed), supplemental oxygen to treat hypoxemia (if present), and the provision of adequate analgesia (if indicated). PSP is rarely life-threatening, and the associated breathlessness is typically mild, often only affecting severe exertion; some patients may also experience pain. The clinical features of pneumothorax are described separately. (See "Clinical presentation and diagnosis of pneumothorax", section on 'Clinical presentation'.)

Subsequent management is directed at deciding whether air needs to be removed from the pleural space and, if so, by what means. Treatment selection is determined by patient stability and symptom burden, the details of which are discussed below. (See 'Assessment of symptom burden and stability' below and 'Stable patients' below and 'Unstable patients' below.)

Assessment of symptom burden and stability — We assess all patients with PSP for symptom burden and for stability since these features determine whether air needs to be drained from the pleural space.

●Symptom burden – In patients with PSP, dyspnea is often mild and may only be experienced during ambulation. Pain may also be present, and the burden substantially relieved with analgesia. We typically ask if the symptoms occur at rest or during exertion, how they impact activities of daily living, and whether they are perceived as mild or significant. However, assessing symptom burden is challenging since it is perceived differently by each patient and symptoms exist on a spectrum (rather than on a binary scale). (See "Clinical presentation and diagnosis of pneumothorax", section on 'Clinical manifestations'.)

●Stability – The definition of stability suggested by the ACCP [1] includes patients with all of the following (table 2):

•Respiratory rate <24 breaths per minute

•Heart rate <120 and >60 beats per minute

•Normal blood pressure (not defined)

•Room air oxygen saturation >90 percent

•Ability to speak in complete sentences

Ability to walk freely around the emergency department was an additional criterion in a large clinical trial [5], which we also find useful.

All other patients are considered unstable. (See 'Unstable patients' below.)

Tension pneumothorax is rare in patients with PSP (due to the absence of underlying lung disease or precipitating causes, such as mechanical ventilation) [6,7]. It must also be emphasized that mediastinal shift does not necessarily mean 'tension' pneumothorax since tension physiology is associated with hemodynamic instability. Details of the radiographic appearance of and needle decompression for tension pneumothorax are discussed separately. (See "Clinical presentation and diagnosis of pneumothorax", section on 'Pneumothorax appearance and types' and "Initial evaluation and management of blunt thoracic trauma in adults", section on 'Pneumothorax' and "Initial evaluation and management of penetrating thoracic trauma in adults", section on 'Role of needle/finger chest decompression' and "Approach to shock in the adult trauma patient", section on 'Tension pneumothorax'.)

STABLE PATIENTS — All clinically stable patients (table 2) (see 'Assessment of symptom burden and stability' above) with a PSP should be treated with adequate analgesia and reassurance and reassessed for symptoms. Initial management depends upon pneumothorax-related symptoms (after adequate analgesia). Additional factors include the presence of bilateral pneumothorax, concurrent pleural effusion that may need to be drained, presence of complex loculations, and patient preference.

Minimal symptoms — Clinically stable patients (table 2) (see 'Assessment of symptom burden and stability' above) with PSP who have minimal symptoms (eg, pain, dyspnea) should be treated with observation with or without supplemental oxygen and be discharged, if feasible. The rationale for this approach is based on data from one randomized trial that suggests most patients in this category improve with this strategy and can avoid an invasive procedure for the removal of air [5]. The data to support this approach of observation with or without oxygen are discussed below. (See 'Observation with or without oxygen' below.)

Observation with or without oxygen — Our approach is the following:

●Observation strategy – Observation with or without supplemental oxygen should last about four to six hours, after which, a chest radiograph should be performed.

•If the radiograph demonstrates no progression or an improvement in pneumothorax size, reliable patients with ready access to emergency medical services can be discharged home (off oxygen) with instructions to return if symptoms worsen.

•If the radiograph demonstrates worsening of the pneumothorax, the patient should have a catheter or chest tube thoracostomy and be admitted. As an alternative, an ambulatory one-way valve device (eg, Heimlich valve) may be selected in some patients. (See 'Catheter or chest tube thoracostomy' below.)

Regardless of the patient's disposition, a repeat chest radiograph is typically performed 12 to 48 hours later:

•If the pneumothorax is resolved, patients should be followed up in an outpatient setting within two to four weeks with a repeat chest radiograph and be given instructions to be evaluated in an acute care setting should symptoms recur. (See 'Outpatient follow-up and management' below.)

•If the radiograph demonstrates worsening of the pneumothorax, the patient should have a catheter or chest tube thoracostomy, which requires admission. (See 'Catheter or chest tube thoracostomy' below.)

●Role of oxygen – Limited data support the role of oxygen unless it is required for hypoxemia, which is rare in PSP, and if present, should prompt the clinician to look for an underlying lung disorder. Although frequently administered, we believe that it is unlikely that supplementary oxygen provides clinically relevant benefits if the underlying air leak is still active. High flow oxygen via nasal cannulae (HFNC) should not be used since a small amount of positive pressure is delivered to the upper airway and could theoretically worsen the pneumothorax. For similar reasons, noninvasive positive pressure should also be avoided. (See "Heated and humidified high-flow nasal oxygen in adults: Practical considerations and potential applications" and "Noninvasive ventilation in adults with acute respiratory failure: Benefits and contraindications".)

We are not proponents of administering oxygen solely as a potential therapy to improve the resorption of air from the pleural space. Although commonly administered, only data from animal models report an increased rate of resorption of air from the pleural space when humidified 100 percent oxygen is administered compared with room air [8-10].

●Efficacy – The rationale for observation alone is based upon data suggesting that this conservative strategy benefits most PSP patients, even those with a large pneumothorax, provided they have mild symptoms and fulfill stability criteria (table 2) (see 'Assessment of symptom burden and stability' above) [4,5]:

•In a major trial, 316 patients (14 to 50 years) with large PSP (ie, over 32 percent (figure 1)) who had mild symptoms and fulfilled the safety criteria of stability (table 2) (see 'Assessment of symptom burden and stability' above) were randomized to receive either conservative therapy (ie, observation for first four hours) or an intervention (ie, chest tube attached to a water seal for first hour, followed by clamping for four hours if there was no air leak), after which, a chest radiograph was obtained [5].

-In the conservative group, after four hours, patients underwent an intervention if they had oxygen requirements, severe symptoms not improving with analgesia, symptoms preventing mobilization, evidence of hemodynamic instability, a preference for an intervention, or worsening pneumothorax on chest imaging. Stable patients without enlargement on the chest radiograph who did not receive oxygen and could ambulate comfortably were discharged with follow up instructions.

-In the interventional group, if after four hours the pneumothorax had resolved, patients were discharged; if the pneumothorax had not resolved, patients were admitted for further drainage.

By eight weeks, there was a similar proportion of patients in each group who had successful radiographic re-expansion (>95 percent in each group risk difference -4.1 percentage points). The time to symptom resolution was also similar. In addition, patients in the conservative group had fewer recurrences during the first 12 months (8.8 versus 16.8 percent), fewer days in the hospital, fewer days off work, less need for surgery, and had fewer adverse events (8 versus 26 percent). Importantly, 85 percent of the patients in the conservative group were successfully managed without intervention.

•In a meta-analysis of four studies that included the trial above [5] and three observational studies, observation alone was associated with a shorter length of hospital stay, a lower risk of recurrence (11 versus 18 percent) and readmission, and fewer complications when compared with chest tube drainage [4].

Significant symptoms (dyspnea)

Choosing an option — Options for clinically stable patients with a PSP who have significant dyspnea after adequate analgesia include aspiration or catheter or chest tube thoracostomy with or without an ambulatory device. For most patients, aspiration via a catheter is traditionally performed (provided that expertise is available), although approaches that incorporate ambulatory devices are gaining acceptance. The rationale for this approach is based upon meta-analyses of small randomized trials that report similar recurrence rates at one year and shorter hospital stays with aspiration compared with catheter or chest tube thoracostomy [11] and a large randomized trial that reported that aspiration was better tolerated with fewer adverse events compared with catheter/tube drainage [12]. These trials are discussed in detail below. (See 'Aspiration' below.)

In practice, choosing between aspiration and catheter or chest tube thoracostomy with or without an ambulatory device is often dependent upon availability of local expertise, severity of the presentation, and patient preference. For example, aspiration is less painful than catheter or chest tube insertion. However, the initial failure rate is higher with aspiration (on average one-third of patients), thereby necessitating a second procedure. Some clinicians choose catheter or chest tube thoracostomy when expertise in aspiration is not available or for patients with bilateral or very large pneumothoraces (eg, complete collapse, mediastinal shift), concurrent hemothorax or pleural effusion necessitating drainage, or complex loculated pneumothorax (unusual in PSP).

Although a conservative approach such as observation has been shown to be equivalent to aspiration or catheter/tube drainage in patients with large PSP [5], patients with significant dyspnea generally do not meet the stability criteria necessary for observation. Data to support observation in stable patients with mild symptoms are discussed above. (See 'Observation with or without oxygen' above.)

Aspiration — Aspiration can be performed using a venous catheter or, more commonly, a catheter from a commercial thoracentesis kit. Using a Seldinger technique, the catheter is typically introduced into the second intercostal space at the midclavicular line. This may need to vary if the lung is tethered on chest radiograph (ie, loculated pneumothorax). Once the catheter is in place, air is manually aspirated usually until resistance is met or when about 2.5 L of air has been removed.

●Once resistance is felt during aspiration and no more air can be aspirated, different approaches may be applied at the discretion of the clinician [13]:

•The stopcock can be closed and the catheter secured to the chest wall. A chest radiograph should be obtained four hours later:

-If the lung is fully expanded and symptoms have improved, the catheter can be removed and the patient discharged with appropriate clinical and radiographic follow up within 24 to 48 hours [14].

-If the lung has not expanded fully or the radiograph demonstrates worsening of the pneumothorax, catheter or chest tube thoracostomy is typically performed. (See 'Catheter or chest tube thoracostomy' below.)

•Alternatively, the catheter can be left in place and attached to a portable one-way valve (picture 1). The patient can then be discharged (provided their symptoms are improved), with clinical and radiographic follow-up within one to two days [1,15,16]. If follow-up imaging demonstrates recurrence, then a catheter or chest tube thoracostomy is typically needed. (See 'Ambulatory pleural drainage with a one-way valve device' below and 'Catheter or chest tube thoracostomy' below.)

●If aspiration fails (eg, no resistance after aspiration of a significant volume of air), it is likely that there is a persistent air leak (PAL). Depending on the circumstances, the aspiration catheter can be left in situ and connected to an underwater seal drainage system or a catheter or chest tube can be placed to provide ongoing drainage, usually as an inpatient. (See 'Catheter or chest tube thoracostomy' below.)

Several studies support aspiration in patients with a PSP rather than catheter or chest tube thoracostomy (small- or large-bore); most are observational or small randomized trials that report efficacy rates ranging from 30 to 80 percent, shorter hospital stays, and fewer complications with aspiration [4,11,12,17-28]. As examples:

●One 2017 meta-analysis of six studies (435 patients) reported that simple aspiration was associated with a shorter hospital stay (mean difference -1.66 days, 95% CI -2.28 to -1.04) and a lower adverse event rate compared with tube thoracostomy without an ambulatory device. Aspiration was associated with lower rates of immediate success (risk ratio [RR] 0.78, 95% CI 0.69-0.89), although the success rates at one year were the same in both interventions (RR 1.07, 95% CI 0.96-1.18) [11]. Most of the included trials were small and did not include the trial in bullet below [12]. A subsequent 2018 network meta-analysis of 29 trials and a 2023 meta-analysis of nine trials reported similar results [4,27].

●A subsequent multicenter study randomized 402 patients with large 'complete' pneumothoraces (ie, lung completely separated from lateral chest wall on radiographs) to either simple aspiration or insertion of 16 or 20 French chest tubes [12]. In the trial, simple aspiration was performed with a catheter that was connected to a suction device at -25 cm H₂O (to avoid variations from manual aspiration) for 30 minutes and could be repeated. Despite an initial lower rate of full radiographic expansion in the aspiration group (71 versus 82 percent), there was a similar one-year recurrence rate in both groups (20 percent [aspiration] versus 27 percent [chest tube]). Consistent with other studies, patients in the aspiration group reported less pain (mean difference: -1.4 on a 10-point scale).

Other options — As an alternative to aspiration in patients with a PSP who have significant symptoms, ambulatory chest tube drainage with a one-way valve or catheter or chest tube thoracostomy are options.

Ambulatory pleural drainage with a one-way valve device — The ambulatory device may be useful for patients who failed conservative management or patients who have a PAL but wish to avoid hospitalization.

A randomized clinical trial tested a device ('Pleural Vent') for ambulatory drainage of PSP. The device consists of a small-bore catheter attached to a one-way valve and is usually placed in the anterior upper chest [17]. In that study, 236 patients were randomly assigned to the ambulatory device for PSP drainage or standard care (aspiration with a 14 to 16 gauge cannula followed by the insertion of a chest tube, if aspiration was ineffective). Included patients were young (16 to 55 years of age; mean 30 years), had symptoms, were clinically stable, and had no evidence of underlying lung disease.

●In the ambulatory arm, patients were observed for one to two hours and if a chest radiograph showed no progression, the patients were discharged, provided they had no oxygen requirements and were clinically stable, mobile, and able to care for themselves.

●All other patients were admitted.

The ambulatory strategy resulted in a lower length of stay (median difference two days, 95% CI 1-3), but patients had a higher rate of adverse events (55 versus 39 percent) that were mostly device- or pneumothorax-related (eg, enlarging pneumothorax, device dislodgement or blockage). Although the ambulatory strategy was associated with a lower rate of recurrence at seven days (7 versus 19 percent), the recurrence rate at 12 months was similar (24 versus 28 percent) as was the surgical referral rate (28 versus 22 percent).

Catheter or tube thoracostomy — Many physicians choose this option likely due to the ease with which the catheters can be placed, their wide availability, the lower immediate failure rate when compared with aspiration, and the ability to use them for continued drainage using a water seal device (requiring hospital admission) or an ambulatory device (allowing select patients to be discharged) [12,17]. These options are discussed separately. (See 'Catheter or chest tube thoracostomy' below and 'Ambulatory pleural drainage with a one-way valve device' above.)

UNSTABLE PATIENTS — Patients with PSP who are unstable (table 2) (see 'Assessment of symptom burden and stability' above) should undergo catheter or chest tube thoracostomy. The rationale for this strategy is based upon the assumed high likelihood of clinical worsening and the higher risk of recurrence in these subgroups.

Other indications for a catheter or chest tube thoracostomy are listed below. (See 'Catheter or chest tube thoracostomy' below.)

Catheter or chest tube thoracostomy — In addition to unstable patients (table 2) (see 'Assessment of symptom burden and stability' above), catheter or chest tube thoracostomy is also appropriate in the following:

●Patients with severe dyspnea

●Patients with tension pneumothorax (rare in PSP)

●Patients with bilateral pneumothorax

●Patients with concurrent hemothorax

●Patients with a pleural effusion necessitating drainage

●Patients with complex loculated pneumothorax (unusual in PSP)

●Patients who are clinically stable and fail observation or aspiration or in whom aspiration cannot be performed due to lack of expertise

Specific to patients with PSP, our approach to catheter or chest tube insertion is the following:

●Drainage device type – Choosing between a catheter or chest tube drainage device is often at the discretion of the clinician and available expertise. Catheter thoracostomy refers to the insertion of a catheter (eg, pigtail catheter), usually by Seldinger technique (figure 2), while chest tube thoracostomy refers to the insertion of a large bore chest tube, usually by blunt dissection.

We often choose small-bore catheters, which are increasingly used, because they are easy to place, less painful, and are sufficiently effective in most patients compared with tube thoracostomy. While both can be placed blindly, ultrasound or other imaging modalities (eg, fluoroscopy, computed tomography [CT]) should be used to guide placement when the pneumothorax is small or loculated. However, if the patient has impending respiratory failure or hemodynamic instability due to pneumothorax, tube thoracostomy without image guidance should be performed immediately as a life-saving maneuver.

The technique of insertion for each type of thoracostomy tube is described separately. (See "Thoracostomy tubes and catheters: Placement techniques and complications".)

●Size – No clear data exist to guide size of chest drain for PSP. In most patients with PSP, we use a small-bore catheter (≤14 French) or a chest tube (≤22 French) [16,21,29-31]. In most cases, a small caliber tube or catheter is sufficient for the drainage of air in patients with PSP. It is unusual in this population that an indication for a large-bore chest tube (eg, 22 to 28 French) is present unless the patient is unstable with tension pneumothorax, concomitant drainage of viscous pleural fluid (eg, empyema) or blood is needed, or small-bore catheter drainage is insufficient.

One systematic review that compared small-bore pigtail catheters with large-bore chest tubes in patients with both PSP and secondary spontaneous pneumothorax reported that the success rate was similar in both groups (80 versus 83 percent), but pigtail catheters had a lower complication rate (odds ratio 0.49) and were associated with a shorter drainage duration (mean difference -1.51 days) and hospital stay (mean difference -2.54 days) [32]. (See "Thoracostomy tubes and catheters: Indications and tube selection in adults and children" and "Treatment of secondary spontaneous pneumothorax in adults", section on 'Tube or catheter thoracostomy'.)

●Water seal or suction – For the majority of patients, we do not initially apply suction and the catheter or tube is connected to a water seal device only. We apply suction (either wall suction or an ambulatory suction device) if the lung fails to re-expand within the subsequent 24 to 48 hours, worsens despite drainage, or a prolonged (also known as persistent) air leak (PAL) develops. In some cases, a second drainage device may be needed.

If suction is warranted, we initiate low-level suction (eg, -10 to -20 cm H₂O) and assess patient tolerance before increasing the suction.

There are limited data to support the use of suction or to guide optimal suction strategy. On one hand, lung re-expansion is achieved in 70 percent of patients within 72 hours without suction [16,33]. On the other hand, suction may increase the risk of re-expansion pulmonary edema or lead to a delay in healing by prolonging air flow through the leak.

Further details regarding suctioning are described separately. (See 'Follow-up thoracostomy management (one to five days)' below and "Alveolopleural fistula and prolonged air leak in adults", section on 'Quantifying the air leak' and "Large volume (therapeutic) thoracentesis: Procedure and complications", section on 'Re-expansion pulmonary edema'.)

●Efficacy – Data that compare aspiration with catheter or chest tube thoracostomy are described above. (See 'Aspiration' above.)

Follow-up thoracostomy management (one to five days) — For patients with a PSP in whom a catheter or chest tube has been placed, follow-up over the subsequent one to five days usually involves daily bedside assessment for symptoms (such as presence of an air leak or surgical emphysema) and for complications of the catheter or chest tube (eg, blockage, pain, bleeding). Daily imaging with chest radiography is not always necessary, although frequent imaging is typically performed to assess the degree of lung expansion. Imaging should also be obtained when symptoms worsen to evaluate for worsening pneumothorax on the ipsilateral side or development of a new pneumothorax on the contralateral side as well as for tube thoracostomy position.

Digital devices to quantify the size of the air leak have been described but are not typically routine [34]. Limited data suggest that measuring the leak size with digital manometry to identify those with large leaks predicts treatment failure and a longer hospital stay, although further data are needed to confirm this finding [35].

Further imaging and management strategies depend upon whether the air leak has sealed or is persistent. (See 'Sealed air leak' below and 'Prolonged air leak' below.)

Sealed air leak — Once the air leak has resolved, a chest radiograph should be performed to confirm that the lung has fully expanded.

●Sealed air leak and lung fully expanded – Once the air leak has sealed and the lung is fully expanded, we clamp the catheter/chest tube for 4 to 12 hours. Clamping the catheter/tube prevents inapparent drainage of small amounts of air through the underwater seal system and thus allows recognition of small leaks that would otherwise be missed. Some experts prefer not to clamp the tube because this might lead to the development of a tension pneumothorax.

Clamping should only be performed in units with sufficient nursing experience and precautions should be followed, for example, to keep the clamp outside the bedclothes and visible, instructing the bedside nurse about releasing it if the patient becomes hemodynamically unstable or significantly symptomatic, and obtaining and examining the chest radiograph after a set period (eg, 4 to 12 hours).

•If the pneumothorax has not recurred, the catheter or chest tube can be removed and the patient discharged. (See "Thoracostomy tubes and catheters: Management and removal", section on 'Removal technique'.)

•If the pneumothorax recurs, then the catheter or chest tube is unclamped and the process is repeated. At this point, options include:

-Continuing with catheter or chest tube drainage to water seal for another 24 to 48 hours. Some experts prefer to avoid suctioning for a few more days, under the premise that suctioning may encourage the flow of air through the defect and, thereby, prevent closure. Data to support the latter strategy are largely derived from postsurgical patients and are described separately. (See "Alveolopleural fistula and prolonged air leak in adults", section on 'General supportive care (drainage of air)' and 'Catheter or chest tube thoracostomy' above.)

-Applying suction under the hypothesis that it can increase pleural apposition, which in turn can facilitate closure of the air leak. Such a hypothesis is not proven, although suction is often administered. Suction strategies are described above. (See 'Catheter or chest tube thoracostomy' above.)

-Placing a second catheter or chest tube (rarely needed in PSP) if it is felt that the catheter/tube is not in a good position for drainage (eg, loculated pneumothorax).

●Sealed air leak and lung not fully expanded – If there is no air leak and the lung has not fully expanded, blockage or malposition of the catheter/chest tube should be considered.

•Under these circumstances the catheter/chest tube should be flushed. If blocked, attempts should be made to clear the blockage; if patent, chest CT may be obtained to examine catheter/tube position.

•Chest CT may also be helpful by suggesting noncompliant lung due to underlying visceral thickening, parenchymal fibrosis, or atelectasis (ie, nonexpendable lung). (See "Diagnosis and management of pleural causes of nonexpandable lung".)

Prolonged air leak — A small proportion of patients with a PSP develop a PAL. An air leak is considered prolonged if it continues for five days or longer, although varying definitions exist in the literature ranging from three to seven days. Our general approach is the following:

●Check leak source – We check that the leak is not coming from the drainage chamber, from the tubing, or from around the catheter/chest tube at the skin entry site. This is classically done by clamping the tube at different locations to isolate the site of the leak or by flushing saline up the tube to look for the source of the leak. If the leak is coming from the system, a new drainage procedure may need to be performed. If the leak is alveolar in origin, then a plan needs to be in place to close the defect.

●Plan for defect closure – If it is determined that the defect is due to PAL, patients generally require defect closure. This approach is based upon the premise that the longer an air leak persists, it is less likely that the leak will close spontaneously and more likely that a definitive intervention (eg, surgical repair of the leak) will be required [4,36].

However, the exact approach to defect closure varies among experts and depends upon factors including the degree of lung expansion, local expertise, and patient values and preferences. We use a multidisciplinary approach that includes an interventional pulmonologist and a thoracic surgeon to facilitate this decision. Notably, the listed procedures in the approach outlined in the bullets below are primarily done to seal the air leak rather than prevent recurrence:

●For patients with PSP and a PAL, surgery is the preferred option, usually video-assisted thoracoscopic surgery (VATS) repair of the defect followed by pleurodesis. This is irrespective of the size of the residual pneumothorax. This preference is based upon the limited likelihood that the leak will resolve spontaneously and that VATS repair is the most effective means to achieve this endpoint. Data that support the efficacy of VATS are discussed below (See 'Video-assisted thoracoscopic surgery' below.)

●When surgery is not feasible/available, alternatives include ambulatory drainage devices, continued catheter or chest tube drainage, chemical pleurodesis, autologous blood patch, and endobronchial valves. Choosing among these is dependent upon local expertise and patient preference.

•Data to support drainage with an ambulatory device are limited. One meta-analysis of four randomized trials reported a reduction in the length of hospital stay following ambulatory management when compared with "standard" care (3.5 days shorter), but no difference in recurrence, rate of hospital readmission, need for pleural procedures, or complications [4]. Choosing among available ambulatory devices is outlined in the table (table 3) and is discussed separately. (See "Pneumothorax: Definitive management and prevention of recurrence", section on 'Definitive measures' and "Alveolopleural fistula and prolonged air leak in adults", section on 'Nonsurgical pleural procedures'.)

•Pleurodesis provides a rapid and definitive resolution for those who fail conservative therapy or continued catheter or chest tube drainage. Chemical pleurodesis may be the only option for those who are not surgical candidates. (See "Pneumothorax: Definitive management and prevention of recurrence", section on 'Pleurodesis' and "Chemical pleurodesis for the prevention of recurrent pleural effusion".)

•Endobronchial valves are not generally needed for the treatment of PSP but are more commonly used for the treatment of PALs from other causes, the details of which are discussed separately. (See "Alveolopleural fistula and prolonged air leak in adults", section on 'Bronchoscopic interventions'.)

Video-assisted thoracoscopic surgery — VATS is mostly used to treat PALs and is not a primary or routine therapy for PSP.

Data describing outcomes from VATS in PSP are limited [4,27]. As an example, a 2023 meta-analysis of seven studies (two randomized trials and five observation series) reported that in patients with a first episode of PSP, VATS was associated with reduced recurrence and shorter length of hospital stay when compared with chest tube thoracostomy [4]. However, pneumonia and air leaks also appeared to be greater following VATS. In contrast, a network meta-analysis of 29 studies reported that in patients with a first episode of PSP, recurrence rates were similar when VATS, tube thoracostomy, and aspiration were compared [27].

RECURRENCE

Management — For patients with previous PSP who recur with an ipsilateral or contralateral pneumothorax, the acute management should be similar to that of the first episode. However, a definitive procedure to prevent recurrence (eg, surgical pleurodesis) should be considered during the same admission or very soon after discharge.

The rationale for this approach is based upon the high risk of recurrence and, additionally, in the case of contralateral pneumothorax, the risk of bilateral pneumothorax. (See 'Catheter or chest tube thoracostomy' above and "Treatment of secondary spontaneous pneumothorax in adults" and "Pneumothorax: Definitive management and prevention of recurrence".)

Indications for definitive procedure after first event — Unlike those with secondary spontaneous pneumothorax, most patients after a first episode of PSP do not need to undergo a definitive procedure (eg, pleurodesis with blebectomy) because the likelihood of recurrence is considered low and prolonged (persistent) air leaks (PALs) are unusual. (See "Pneumothorax: Definitive management and prevention of recurrence", section on 'Primary spontaneous pneumothorax'.)

Although practice varies widely, there is general consensus among experts that a small population of patients with a first episode of PSP can be selected to undergo a definitive procedure including the following (algorithm 1):

●Patients with a PAL (see 'Prolonged air leak' above)

●Patients with a high-risk occupation (eg, airline pilot, deep sea diver) or hobby (eg, SCUBA diving)

●Patients with contralateral, bilateral, or life-threatening PSP

Other less well-established indications include the following:

●Patients undergoing thoracoscopy for an alternate indication (eg, hemothorax, lung biopsy)

●Patients with a significant number of cysts or blebs on imaging (although the exact number is not defined)

●Patients with significant symptoms or hemodynamic consequences during their first PSP

The rationale for a definitive procedure in these patients is based upon the assumption (not supported by evidence) that, among patients with PSP, the risk of recurrence and risk of harm from recurrence is greatest in these subgroups (see "Pneumothorax: Definitive management and prevention of recurrence", section on 'Incidence of recurrence'). Data to support these indications, however, are sparse. In one small study of 214 patients with PSP (>2 cm from the pleural line to the chest wall), at one year, chemical pleurodesis with minocycline was more effective at preventing recurrence than no pleurodesis (29 versus 50 percent) [37]. Future studies should focus on defining which patients with PSP are at the highest risk of recurrence so that a targeted preventive intervention may be performed selectively.

Other reasons to opt for a definitive procedure include the following:

●Patients with a strong desire to avoid recurrence. Some patients have a strong desire to avoid recurrence while others are procedure averse.

●Patients with a first PSP who have another indication for thoracoscopy. For example, some patients who require a diagnostic lung biopsy (eg, if catamenial pneumothorax is suspected) or patients with hemopneumothorax who need a thoracoscopy to remove frank blood from the pleural space (ie, to avoid future trapped lung). In these circumstances, some surgeons choose to perform a definitive procedure (eg, abrasion and/or blebectomy) at the time of surgery because the additional risk is considered relatively low.

Further discussion regarding recurrence rates and the type of definitive procedures available to prevent recurrence is provided separately. (See "Pneumothorax: Definitive management and prevention of recurrence".)

OUTPATIENT FOLLOW-UP AND MANAGEMENT — Following resolution of a pneumothorax, whether spontaneously, with a thoracostomy or with an ambulatory device, or after a definitive procedure, patients should be clinically and radiologically evaluated in about two to four weeks as outpatients. In the intervening period, they are instructed to return to the hospital if they develop symptoms of chest pain or dyspnea since recurrence is greatest during the first month after presentation.

During that evaluation, we suggest the following:

●Radiologic evaluation – We obtain chest radiography to ensure continued full expansion of the lung. We do not generally perform chest CT unless the pneumothorax was loculated or complex or we suspect an underlying lung disorder.

●Clinical evaluation – We clinically assess patients for chest pain or dyspnea that would suggest possible recurrence or postpleurodesis pain.

We also assess patients with PSP for any potential diagnoses missed during the initial evaluation. If a previously unidentified underlying lung process is discovered, then patients should be treated as if they have secondary spontaneous pneumothorax (SSP; ie, pneumothorax due to underlying lung disease) and electively undergo a definitive procedure, should they be agreeable to it.

Patients with SSP should be evaluated for control of their underlying lung disease.

Further details regarding postdiagnosis evaluation for patients with PSP and treatment of SSP are provided separately. (See "Clinical presentation and diagnosis of pneumothorax", section on 'Postdiagnosis evaluation' and "Treatment of secondary spontaneous pneumothorax in adults".)

●Smoking – We advise patients to stop smoking cigarettes as well as other tobacco products, marijuana, and illicit drugs. Although poorly studied, the strong association between smoking and pneumothorax suggests that smoking cessation may help prevent recurrence [38]. In addition, smoking has been shown in one retrospective study to predict a higher recurrence rate in those who undergo pleurodesis [39]. (See "Overview of smoking cessation management in adults".)

●Inquiry into familial history/genetics – For some patients, a spontaneous pneumothorax can be the first indication of a genetic disorder [40]. Birt-Hogg-Dubé syndrome, Marfan syndrome, tuberous sclerosis-related lymphangioleiomyomatosis, and alpha-1 antitrypsin deficiency can all present with pneumothorax. Thus, consideration of family history, suggestive physical findings, and/or chest CT findings may lead to a referral to a geneticist and potential benefits of surveillance for other extrapulmonary complications for the patient and their family members.

●Air travel – An acute pneumothorax is an absolute contraindication for air travel. After therapy, the optimal time for avoiding air travel is unknown but patients are typically advised not to travel by air for at least one to three weeks. However, it likely depends upon the type of treatment the patient received (eg, simple aspiration, tube thoracostomy, chemical or mechanical pleurodesis) and the estimated risk of recurrence. Air travel and pneumothorax is discussed in greater detail separately. (See "Pneumothorax and air travel".)

●Deep sea diving – Patients should be advised to avoid SCUBA diving for life. Experts suggest that diving be permanently avoided unless the patient has undergone bilateral surgical pleurectomy and has normal lung function and CT scan. (See "Pneumothorax and air travel" and "Complications of SCUBA diving".)

●Exercise – Exercise can be gradually reintroduced two weeks after treatment, but introduction of contact sports, heavy weightlifting, or extreme forms of exercise may warrant longer periods of avoidance.

SPECIAL POPULATIONS — Management of special populations of patients with pneumothorax are discussed separately:

●Patients with pneumothorax due to underlying lung disease (ie, secondary spontaneous pneumothorax) (see "Treatment of secondary spontaneous pneumothorax in adults")

●Patients with pneumothorax who are pregnant (see "Treatment of secondary spontaneous pneumothorax in adults", section on 'Pneumothorax and pregnancy')

●Patients with iatrogenic pneumothorax (see "Treatment of secondary spontaneous pneumothorax in adults", section on 'Other pneumothorax types')

●Patients with pneumothorax due to trauma (see "Initial evaluation and management of blunt thoracic trauma in adults", section on 'Pneumothorax')

●Patients with pneumothorax due to miscellaneous causes (eg, exercise, anorexia) (see "Treatment of secondary spontaneous pneumothorax in adults", section on 'Other pneumothorax types')

SOCIETY GUIDELINE LINKS — Links to society and government-sponsored guidelines from selected countries and regions around the world are provided separately. (See "Society guideline links: Pneumothorax".)

INFORMATION FOR PATIENTS — UpToDate offers two types of patient education materials, "The Basics" and "Beyond the Basics." The Basics patient education pieces are written in plain language, at the 5^th to 6^th grade reading level, and they answer the four or five key questions a patient might have about a given condition. These articles are best for patients who want a general overview and who prefer short, easy-to-read materials. Beyond the Basics patient education pieces are longer, more sophisticated, and more detailed. These articles are written at the 10^th to 12^th grade reading level and are best for patients who want in-depth information and are comfortable with some medical jargon.

Here are the patient education articles that are relevant to this topic. We encourage you to print or e-mail these topics to your patients. (You can also locate patient education articles on a variety of subjects by searching on "patient info" and the keyword(s) of interest.)

●Basics topic (see "Patient education: Pneumothorax (collapsed lung) (The Basics)")

SUMMARY AND RECOMMENDATIONS

●Initial evaluation and management – Although approaches to the management of primary spontaneous pneumothorax (PSP) vary widely, ours is one that primarily incorporates patient stability and symptom control. (See 'Initial evaluation and management' above.)

•General assessment – Following resuscitation (if indicated), supplemental oxygen (if indicated), and adequate analgesia, subsequent management is directed at deciding whether air needs to be removed from the pleural space and, if so, by what means. (See 'General principles' above and 'Symptom control' above.)

•Stability assessment – The definition of a stable patient is found in the table (table 2). All other patients are considered unstable. (See 'Assessment of symptom burden and stability' above.)

●Management of a clinically stable patient with PSP and minimal dyspnea – For most patients with PSP who are clinically stable and have minimal dyspnea after adequate analgesia, we recommend conservative management (eg, monitored observation) rather than aspiration or catheter/chest tube insertion (Grade 1B). A small subset does, however, require a drainage intervention (eg, 15 percent).

The rationale for this approach is based upon randomized trial evidence demonstrating that most patients in this category improve with a conservative strategy and can avoid an invasive procedure for the removal of air (up to 85 percent). (See 'Stable patients' above and 'Minimal symptoms' above.)

Follow-up involves the following:

•The patient should be observed, and a repeat chest radiograph obtained four to six hours later. If the radiograph demonstrates improvement or excludes progression of the pneumothorax and the patient has access to emergency medical services, the patient can be discharged home.

•Patients who demonstrate worsening of the pneumothorax on repeat imaging can be managed with a catheter or chest tube thoracostomy, which requires admission. An ambulatory device with a one-way valve is an alternative option (table 3), although the evidence to support it is limited.

●Management of a clinically stable patient with PSP and significant dyspnea – For most patients with PSP who are clinically stable and have moderate or significant dyspnea after adequate analgesia, we suggest a simple aspiration drainage procedure (typically with a catheter) rather than a catheter or chest tube thoracostomy (Grade 2C). The aspiration procedure is described above. (See 'Significant symptoms (dyspnea)' above and 'Aspiration' above.)

The rationale for this approach is based upon data from randomized trials that report similar recurrence rates, shorter hospital stays, better tolerance, and fewer adverse effects with aspiration compared with thoracostomy. However, in practice, choosing between aspiration and catheter or chest tube thoracostomy or an ambulatory drainage device is often dependent upon local expertise, severity of the presentation, and patient preference.

Patients in whom aspiration fails or is not feasible (eg, expertise is lacking) require definitive drainage with catheter or chest tube thoracostomy. The advantage of catheter or chest tube thoracostomy is that they are widely available, have lower immediate failure rates when compared with aspiration, and can be used for continued drainage using a water seal device (requiring hospital admission) or an ambulatory device (allowing select patients to be discharged). (See 'Significant symptoms (dyspnea)' above and 'Catheter or chest tube thoracostomy' above.)

●Management of unstable patients – Patients who do not meet stability criteria (table 2) and patients with severe dyspnea, tension pneumothorax, bilateral pneumothorax, concurrent hemothorax, a pleural effusion necessitating drainage, or complex loculated pneumothorax (unusual in PSP) require an intervention. For most patients, we suggest a definitive drainage procedure (eg, catheter or chest tube thoracostomy) rather than a simple aspiration procedure (Grade 2C). If tension is present and chest tube insertion is delayed, immediate needle decompression should be performed. Management of tension pneumothorax is discussed separately. (See 'Unstable patients' above and "Initial evaluation and management of blunt thoracic trauma in adults", section on 'Pneumothorax' and "Approach to shock in the adult trauma patient", section on 'Tension pneumothorax'.)

The rationale for this strategy is based upon the assumed high likelihood of clinical worsening and the higher risk of recurrence in these patients.

•Drainage tube management – For patients in whom a catheter or chest tube thoracostomy is indicated, a small-bore catheter (≤14 French) or tube (≤22 French) is generally used without suction. Large-bore tubes (24 to 28 French) are reserved for when patients are unstable, have concomitant empyema or hemothorax, or have failed small-bore drainage.

•Follow-up – Most pneumothoraces resolve with these initial thoracostomy management strategies. (See 'Follow-up thoracostomy management (one to five days)' above.)

-Sealed air leak – For those in whom the air leak has sealed and the lung is fully expanded, the catheter/chest tube can be removed and the patients can be discharged. (See 'Sealed air leak' above and "Thoracostomy tubes and catheters: Management and removal", section on 'Removal'.)

-Persistent air leak (PAL) – In patients with PSP who have a persistent air leak (PAL; eg, beyond five to seven days), we suggest video-assisted thoracoscopic surgery (VATS) repair of the defect rather than continued drainage (Grade 2C). This approach is based upon the limited likelihood that the leak will resolve spontaneously and that VATS repair is the most effective means to achieve this defect closure. When surgery is not feasible/available, alternative options include ambulatory drainage devices, continued catheter or chest tube drainage, chemical pleurodesis, autologous blood patch, and endobronchial valve placement. Choosing among these is dependent upon expertise and patient preference. (See 'Prolonged air leak' above and 'Video-assisted thoracoscopic surgery' above.)

●Recurrence prevention – Intervening to prevent recurrence depends upon whether it is a first or recurrent event, the expected risk of recurrence after each event, and patient values and preferences (algorithm 1). Our approach is the following:

•First occurrence, high risk for recurrence – For patients with PSP who have the following risk factors, we suggest a definitive preventative procedure (Grade 2C):

-PALs not responsive to therapy

-A high-risk occupation or hobby (eg, airline pilot, deep sea diver)

-Contralateral, bilateral, or life-threatening PSP

-A high burden of cysts

-Another indication for thoracoscopy (eg, hemothorax, lung biopsy)

-Significant symptoms or hemodynamic consequences during their first PSP

The rationale for this approach is that these patients likely have a higher than usual risk of recurrence after the first event. The definitive procedure is typically VATS resection of blebs with pleurodesis, although the optimal procedure is controversial.

•First occurrence, low risk for recurrence – Most patients with a first episode of PSP who lack the risk factors on the bulleted list above do not require a definitive procedure to prevent recurrence because the recurrence rate is low and PALs are unusual in this population. The incidence of recurrence is discussed separately. (See 'Indications for definitive procedure after first event' above and "Pneumothorax: Definitive management and prevention of recurrence", section on 'Primary spontaneous pneumothorax'.)

•Recurrent pneumothorax – Patients with recurrent PSP (ipsilateral or contralateral) are managed with the same strategy as the first event. However, in these cases, we suggest a definitive intervention to prevent recurrence (Grade 2C) since the risk of recurrence is high. Intervention is typically performed before or after discharge since recurrence is highest in the first 30 days after the initial presentation. (See 'Recurrence' above and "Pneumothorax: Definitive management and prevention of recurrence", section on 'Incidence of recurrence'.)

●Outpatient follow-up – Following treatment, patients should be evaluated in about two to four weeks as an outpatient.

•Chest radiography is performed to ensure continued full expansion of the lung.

•Patients should be reassessed for any potential diagnoses missed during the initial evaluation (which may involve CT of the chest) and, if an etiology is discovered, treated as if they had secondary pneumothorax.

•Patients should be advised to stop smoking cigarettes (as well as other tobacco products, marijuana, and illicit drugs) and to avoid air travel and exercise for a limited period. SCUBA diving should be avoided for life. (See 'Outpatient follow-up and management' above and "Pneumothorax and air travel" and "Evaluation of adults wishing to SCUBA dive", section on 'Absolute and relative contraindications'.)

ACKNOWLEDGMENT — The UpToDate editorial staff acknowledges Richard W Light, MD, now deceased, who contributed to earlier versions of this topic review.