Treatment of debilitated and pre-septic or septic patients with pleural empyema is still a challenge. Even in the case of successful empyema management, patients with multimorbidity, malignancy, and/or immunosuppression have a worse short-term prognosis (mortality up to 15 %, Table
5) and long-term prognosis with a median survival of 22.8 to 67 months [
7,
8] than patients without such additional complications.
Table 5
Overview; outcomes of OWT therapy in debilitated patients
Maruyama et al. 2001 | 53 | Heterogeneous | 15 % (8/53) | 83 % (44/53) | 11 % (5/44) | Mean 128.0+/−32.1 days |
Thourani et al. 2003 | 78 | Heterogeneous | 5 % (4/78) | definitive OWT | definitive OWT | definitive OWT |
Massera et al. 2009 | 19 | Heterogeneous | 6 % (1/17) | 59 % (10/17) | 10 % (1/10) | Median 5 (3-9 months) |
Reyes et al. 2010 | 78 | Heterogeneous | 6 % (5/78) | 22 % (17/78) | 6 % (1/17) | Median 454 (90–1068 days) |
Our study showed that intrathoracic VAC technique offers a safe treatment option for pleural empyema with good short-term and long-term outcomes, particularly in debilitated patients.
Short-term outcome
Minimally invasive treatment with Mini-VAC and Mini-VAC-Instill significantly reduces the duration of vacuum treatment in comparison to OWT-VAC. The length of stay in hospital could also be reduced by the Mini-VAC(−Instill) procedure, although − in almost all minimally invasive treated patients (22/23) − final chest wall closure was conducted during the same hospital stay, which additionally extended LOS. In addition, a previous study of our group showed the efficacy of wound flushing in combination with vacuum in invasive aggressive empyema thoracis – i.e. highly aggressive bacteria or reduced immunity of patients [
9].
So, the last treatment period (2013 to 2014) showed that both treatment duration and LOS could be significantly reduced by Mini-VAC-Instill therapy in comparison to the OWT-VAC and Mini-VAC technique.
To date, only few authors have achieved similar LOS for thoracic empyema [
10,
11]. Schneiter at al. reported a mean hospitalization of 18 days for early and late postpneumectomy empyema with repeated open surgical debridements and antimicrobial therapy [
10]. The thorax was definitively closed in 71 of 75 (94.6 %) patients. Thourani et al. treated 78 empyema patients with definitive OWT (modified Eloesser flap) and reported a mean LOS of 16 days [
11]. But the modified Eloesser flap procedure was intended as a permanent one-stage procedure. So, in the study by Thourani et al., treatment duration was equivalent to LOS.
In our opinion, the dressings should be routinely changed every three to four days, in the operating room, to allow precise and continued monitoring of infection. In the presence of residual lung tissue we often use the thoracoscope for better visualisation of poorly visible areas.
This means that repeat debridement treatment can be performed as required to keep the wound bed clean for optimal healing.
We treated two patients with definitve BPF and in all the installation of vacuum was possible. In one patient with a one mm fistula, the BPF was sufficiently closed after VAC therapy. The other BPF, with a diameter of eight millimetres, could not be closed by VAC, which was not a problem in the VAC treatment. Future studies should investigate the diameter of BPF that can be closed by negative pressure in VAC therapy.
The largest literature series of OWT patients with heterogeneous causes of empyema (excluding postpneumectomy empyema) showed 30-day mortality rates between 5 and 15 % (Table
5). The OWT procedure may result in a good prognosis in medical unstable and debilitated patients. The most common causes of death after OWT are sepsis and multiorgan failure [
7,
8,
11‐
13]. In our study, we lost only 2 patients due to cardiac and multiorgan failure, which resulted in a 30-day mortality rate of 4.6 % (2 of 43). Therefore, VAC treatment, particularly of the minimally invasive type, offers the same survival prognosis than classical OWT treatment but a higher rate of chest wall closures.
The most important advantage of Mini-VAC and Mini-VAC-Instill therapy is probably immediate chest wall closure after VAC treatment. We preferred conducting chest wall closure during the same hospital stay to avoid later complications including hospitalization and to improve quality of life. In the Mini-VAC group, all thoracic windows were closed, and only one definitive fenestration was left in the Mini-VAC-Instill group. Indispensable requirements for chest wall closure were good macroscopic aspects and negative microbiological cultures. In the study by Palmen et al. [
14], 50 % of patients died of OWT-related complications (bleeding and recurrent infections) during follow-up.
Although empyema thoracis recurred once in the Mini-VAC-Instill group, there were no pitfalls on this case.
A recent Cox proportional hazard model showed a significant association of the closure of OWTs (HR 0.31, 95 % CI 0.10–0.88;
p = 0.03) with overall survival [
7]. In our study, successful chest wall closure was not significantly associated with survival (HR 0.81, 95 % CI 0.29–2.31;
p = 0.695).
Long-term outcome
The 4-year survival rate of all patients was 50 %, and no case of death was related to intrapleural vacuum therapy. We found no prognostic factor for death or survival, and even malignancy had a
p-value of 0.091 (Table
4).
Reyes et al. achieved survival rates of 74 and 60 % at 12 months and 60 months [
13], when treating 78 debilitated patients with empyema with OWT. In the study by Hato et al., the 60-month survival rate of OWT patients was 34.7 % (12 of 35), whereas the median survival period was 22.8 months. According to the univariate analyses, variables significantly associated with increased overall survival included closure of the OWT (
p = 0.03) and absence of diabetes mellitus (
p = 0.04) [
7]. The long-term survival of this vulnerable patient population is mainly determined by secondary diseases rather than by the type of treatment. Taking this fact into consideration, the primary goal should be prompt empyema therapy to enable treatment of the underlying disease.
No patient developed systemic symptoms due to the instillation of the 0.02 % polyhexanide solution. We have not seen a negative effect of VAC-(Instill) on the pleura carcinosis. Nevertheless, the use of VAC-Instill therapy can trigger clinically significant complications and there are also some contraindications [
9], including: coagulopathy, larger bronchial stump insufficiency, ongoing pain and contact allergy or anaphylactic reactions. Because of this, cautious monitoring of the VAC system must be exercised in the hospital. Therefore, outpatient management for Mini-VAC-Instill is not recommended.
Although the cost of materials in the Mini VAC (−Instill) groups was considerably higher than in the OWT-VAC group, in the final effect, on grounds of the shorter LOS, the treatment costs were lower in the minimally invasive groups.