Postoperative residual pleural spaces: characteristics and natural history

Long-term outcomes and risk factors of residual thoracic spaces after pleurectomy/decortication for mesothelioma

OBJECTIVES

The residual thoracic spaces (RTS) after pleurectomy/decortication (P/D) remain unexplored to date. Hence, this study aims to examine the details and risk factors of RTS during the 3 post-P/D months.

METHODS

We retrospectively examined patients who underwent neoadjuvant chemotherapy, followed by P/D for malignant pleural mesothelioma from September 2012 to December 2020. The RTS group included cases of residual thoracic cavity unaccompanied by pleural effusion on 3 postoperative months computed tomography. We determined risk factors for RTS using univariable and multivariable analyses.

RESULTS

Of 170 patients examined, 58 (34.1%) were in the RTS group and 112 (65.9%) in the non-RTS group. In the RTS group, 43 patients recovered from RTS during the follow-up period; 4 patients developed chronic fistular empyema, while 2 required fenestration and 2 were thoracoscopic debridement. Besides, 11 patients exhibited RTS continuously. The univariable analysis revealed that compared with the non-RTS group, the RTS group reported a significantly longer postoperative air leak (>7 days; P < 0.01) and right P/D (P = 0.04). The multivariable analysis demonstrated that longer postoperative air leak (>7 days) remained a risk factor for RTS (odds ratio 2.5, 95% confidence interval: 1.3-4.9, P < 0.01).

CONCLUSIONS

RTS was a postoperative event that frequently observed in patients undergoing P/D. Overall, the current study findings suggest longer postoperative air leak (>7 days) as a significant risk factor for RTS.

The “Balloon-Like” Sign: Differential Diagnosis between Postoperative Air Leak and Residual Pleural Space: Radiological Findings and Clinical Implications of the Young–Laplace Equation

Simple Summary

Postoperative residual pleural space and postoperative air leaks after lung resection are two different clinical entities requiring completely different approaches. Residual postoperative pleural space is a part of the pleural cavity that is not fully reoccupied by the remaining lung after pulmonary resection. No treatment is needed in the asymptomatic residual pleural space without any persistent air leak, and chest drain removal can be safely planned. On the contrary, an active and prolonged air leak after lung resection is an absolute contraindication to chest drain removal that may culminate in hypertensive pneumothorax, subcutaneous emphysema, and severe respiratory symptoms. In order to further contribute to an appropriate differential diagnosis between these two settings, we propose a radiological sign that is observed only in the case of residual plural space. In this case, in fact, the lung takes the form of a round balloon due to the hyperinflation condition, which is governed by the Young–Laplace equation describing the capillary pressure difference sustained across the interface between two static fluids, such as water and air, due to the phenomenon of wall tension.

Abstract

In this paper, we propose a radiological sign for an appropriate differential diagnosis between postoperative pleural space and active air leak after lung resection. In the case of residual pleural space without any active air leak, the lung takes the form of a round balloon due to the hyperinflation condition, which is governed by the Young–Laplace equation describing the capillary pressure difference sustained across the interface between two static fluids, such as water and air, due to the phenomenon of wall tension. The two principal mechanisms by which a lung forms a spherical image are shear-controlled detachment induced by shear stress on the membrane surface, and spontaneous detachment induced by a gradient in Young–Laplace pressure. On the contrary, the lung maintains its tapered shape in the case of an active air leak because the continuous air refill does not allow a complete parenchyma re-expansion.

OUP accepted manuscript

Prolonged chest tube drainage is one of the most common postoperative complications of pulmonary resections; it is related to complications such as residual pleural spaces or continuous alveolar air leaks. We retrospectively evaluated the efficacy of artificial intraoperative pneumoperitoneum in the treatment of such complications after lung resections. The presence of a residual space associated with prolonged air leaks can be difficult to treat, exposes the patient to a high risk of infection, prolongs hospitalization, and in some cases mandates reoperation. Between October 2016 and March 2020, four patients underwent pneumoperitoneum. The obliteration of the pleural cavity and the absence of air leaks were observed in 3 patients; only 1 patient was discharged with a Heimlich valve. Artificial intraoperative pneumoperitoneum is a safe and simple procedure. It decreases the duration of chest drainage and of the hospital stay; however, further studies are needed to corroborate our data. The learning curve for this technique may be relatively short.

Management of complex pleural disease in the critically ill patient

Disorders of the pleural space are quite common in the critically ill patient. They are generally associated with the underlying illness. It is sometimes difficult to assess for pleural space disorders in the ICU given the instability of some patients. Although the portable chest X-ray remains the primary modality of diagnosis for pleural disorders in the ICU. It can be nonspecific and may miss subtle findings. Ultrasound has become a useful tool to the bedside clinician to aid in diagnosis and management of pleural disease. The majority of pleural space disorders resolve as the patient’s illness improves. There remain a few pleural processes that need specific therapies. While uncomplicated parapneumonic effusions do not have their own treatments. Those that progress to become a complex infected pleural space can have its individual complexity in therapy. Chest tube drainage remains the cornerstone in therapy. The use of intrapleural fibrinolytics has decreased the need for surgical referral. A large hemothorax or pneumothorax in patients admitted to the ICU represent medical emergencies and require emergent action. In this review we focus on the management of commonly encountered complex pleural space disorders in critically ill patients such as complicated pleural space infections, hemothoraces and pneumothoraces.

Early Induction of Bedside Pneumoperitoneum in the Management of Residual Pleural Space and Air Leaks After Pulmonary Resection

BACKGROUND

The pneumoperitoneum to treat prolonged air leaks or pleural space problems after pulmonary resection has been successfully used for decades. The aim of the study is to describe our experience with the early induction of therapeutic pneumoperitoneum (TP).

METHODS

We reviewed the data of 103 consecutive patients undergoing TP between September 2011 and September 2019. Patients were divided into two groups according to the time of the induction of TP: early application (≥72 h) and standard application (>72 h).

RESULTS

In total, 52 early TP and 51 standard TP were analyzed. The median time of TP induction was 2 (1-3) versus 8 (5-11) postoperative days (POD) (p < 0.001). The time for obliteration of the residual pleural space (7 vs.9 days, p = 0.805) and the time of resolution of the air leaks (14 vs. 16 days, p = 0.663) didn't differ between the two groups, but a favorable trend was observed in the early group. The hospital stay was lower for patients undergoing early pneumoperitoneum: 9 versus 18 days (p < 0.001). The multivariate analysis showed that POD of induction of TP (p < 0.001), time of resolution of the air leak (p < 0.001) and Heimlich valve (p = 0.002) were independent variables associated with the hospital stay.

CONCLUSIONS

The use of TP whenever a space problem or air leaks occur after pulmonary resections is safe and effective. Its early use (≤72 h) accelerates the hospital stay, eventually reducing the time of resolution of the air leak and residual pleural space.

Management of residual pleural space after lung resection: fully controllable paralysis of the diaphragm through continuous phrenic nerve block

Background

Residual pleural space after lung resection associated with air leak is a challenging issue, potentially causing serious complications. We report a new, postoperative technique to reduce the pleural space, inducing a controlled and reversible paralysis of the diaphragm.

Methods

Ten patients were enrolled (7 lobectomies, 2 bilobectomy, 1 wedge resection). Inclusion criteria were: digitally detected air flow >200 mL/min at post-op day 3, presence of empty pleural space at chest x-ray, absence of restrictive lung disease, absence of known arrhythmias. A 22G nerve-block catheter was place under ultrasound guidance in proximity to the phrenic nerve, between the sternocleidomastoid muscle and the anterior scalene muscle at the level of 6^th cervical vertebra. Continuous infusion of ropivacaine 0.2% 3 mL/h was started. Fluoroscopy was used to confirm significant reduction in hemidiaphragm movements. Monitoring of vital signs and intense respiratory physiotherapy were enhanced. The infusion was stopped at air leak cessation and the catheter was removed along with the chest drain.

Results

No peri- and post-procedural complications occurred. In all patients, we observed an immediate reduction of the empty pleural space and resolution of the air leak within few days (3±1.16 days). After suspension of local anaesthetic, complete restoration of the hemidiaphragm function has been documented.

Conclusions

This is an effective and minimally invasive method to reduce the residual pleural space after lung resections. Narrowing of the pleural space facilitates the contact between the lung and the chest wall promoting the resolution of the air leak. Diaphragm paralysis is controlled and temporary with no residual disabilities.

Pathophysiological mechanism of post-lobectomy air leaks

Background

Air leak post-lobectomy continues to remain a significant clinical problem, with upper lobectomy associated with higher air leak rates. This paper investigated the pathophysiological role of pleural stress in the development of post-lobectomy air leak.

Methods

Preoperative characteristics and postoperative data from 367 consecutive video assisted thoracic surgery (VATS) lobectomy resections from one centre were collected prospectively between January 2014 and March 2017. Computer modelling of a lung model using finite element analysis (FEA) was used to calculate pleural stress in differing areas of the lung.

Results

Air leak following upper lobectomy was significantly higher than after middle or lower lobectomy (6.3% versus 2.5%, P=0.044), resulting in a significant six-day increase in mean hospital stay, P=0.004. The computer simulation model of the lung showed that an apical bullet shape was subject to eightyfold higher stress than the base of the lung model.

Conclusions

After upper lobectomy, the bullet shape of the apex of the exposed lower lobe was associated with high pleural stress, and a reduction in mechanical support by the chest wall to the visceral pleura due to initial post-op lack of chest wall confluence. It is suggested that such higher stress in the lower lobe apex explains the higher parenchymal air leak post-upper lobectomy. The pleural stress model also accounts for the higher incidence of right-sided prolonged air leak post-resection.

[Is daily chest X-ray necessary after lung resection? Evidence-based decision making]

OBJECTIVES

The 'gold standard' practice following insertion of a chest tube after lobectomy is daily chest radiography (CXR), but this is not always followed. We compared the outcomes associated with the use of these two methods in our practice.

METHODS

Data from 148 patients who underwent uncomplicated lobectomies with insertion of one chest drain were analysed. In the routine CXR group (R-CXR) (50 patients), an immediate postoperative CXR, daily routine radiography during the drainage period, and one after surgical drain removal were performed. In the symptomatic CXR group (S-CXR) (98 patients), a CXR was performed only for symptomatic patients (fever, hypoxia, subcutaneous emphysema, air leak) and/or a single radiograph was taken after surgical drain removal. The following postoperative data were compared: fever, CXR abnormalities (pneumothorax, fluid, atelectasis, subcutaneous emphysema, haematoma), number of radiographs, drainage time, and new drain insertion.

RESULTS

The mean chest tube duration was 3.7 and 3.8 days in the R-CXR and S-CXR groups, respectively. Abnormal CXRs after surgical drain removal were reported in 50% (25/50) and 46.9% (46/96) (p = 0.724) of patients in the R-CXR and S-CXR groups, respectively, but new drain insertion was only necessary in 3/25 (12%) and 7/46 (15.2%) of these cases. The mean number of CXRs for each patient was 5.0 and 2.3 (p = 0.0001) in the R-CXR and S-CXR groups, respectively.

CONCLUSIONS

If CXRs are limited to symptomatic patients then the number of radiographs can be reduced by around 50%. There were no more postoperative complications or abnormal final CXR findings if the CXR was only ordered for symptomatic patients instead of as 'daily routine' during the postoperative period. Only 12-15% of the CXR abnormalities required surgical intervention.

Portable chest drainage systems and outpatient chest tube management

Ambulatory treatment of pleural problems such as pneumothorax and malignant pleural effusions has been extensively described and is commonly used. On the contrary, outpatient management of chest tubes after lung resection is less frequently performed. Because prolonged air leak after lobectomy is a common problem, early discharge of these patients under pleural drainage can avoid many hospital days without compromising the quality of care. In this article, general rules for outpatient chest tube management are described and available portable devices are reviewed.