ORIGINAL ARTICLE
European Journal of Cardio-Thoracic Surgery 48 (2015) 893–898
doi:10.1093/ejcts/ezu535 Advance Access publication 20 January 2015
Cite this article as: Lijkendijk M, Licht PB, Neckelmann K. Electronic versus traditional chest tube drainage following lobectomy: a randomized trial. Eur J
Cardiothorac Surg 2015;48:893–8.
Electronic versus traditional chest tube drainage following
lobectomy: a randomized trial†
Marike Lijkendijk*, Peter B. Licht and Kirsten Neckelmann
Department of Cardiothoracic Surgery, Odense University Hospital, Odense, Denmark
* Corresponding author. Department of Cardiothoracic Surgery, Odense University Hospital, 29 Sdr. Boulevard, 5000 Odense, Denmark. Tel: +45-2498-8031;
fax: +45-6591-6935; e-mail: [email protected] (M. Lijkendijk).
Received 14 September 2014; received in revised form 4 December 2014; accepted 5 December 2014
Abstract
OBJECTIVES: Electronic drainage systems have shown superiority compared with traditional (water seal) drainage systems following lung
resections, but the number of studies is limited. As part of a medico-technical evaluation, before change of practice to electronic drainage
systems for routine thoracic surgery, we conducted a randomized controlled trial (RCT) investigating chest tube duration and length of
hospitalization.
METHODS: Patients undergoing lobectomy were included in a prospective open label RCT. A strict algorithm was designed for early chest
tube removal, and this decision was delegated to staff nurses. Data were analysed by Cox proportional hazard regression model adjusting
for lung function, gender, age, BMI, video-assisted thoracic surgery (VATS) or open surgery and presence of incomplete fissure or pleural
adhesions. Time was distinguished as possible (optimal) and actual time for chest tube removal, as well as length of hospitalization.
RESULTS: A total of 105 patients were randomized. We found no significant difference between the electronic group and traditional group
in optimal chest tube duration (HR = 0.83; 95% CI: 0.55–1.25; P = 0.367), actual chest tube duration (HR = 0.84; 95% CI: 0.55–1.26; P = 0.397)
or length of hospital stay (HR = 0.91; 95% CI: 0.59–1.39; P = 0.651). No chest tubes had to be reinserted. Presence of pleural adhesions or
an incomplete fissure was a significant predictor of chest tube duration (HR = 1.72; 95% CI: 1.15–2.77; P = 0.014).
Keywords: Air leak • Chest tube • Electronic pleural drainage system • Pulmonary lobectomy • Fast-track surgery • Postoperative
management
INTRODUCTION
Chest tubes are used to evacuate air and fluids following lung
resections, and can be used to monitor when drainage of the chest
cavity is sufficient. Until recently, this field has been managed from
a traditional paradigm or empirical evidence [1]. A number of
factors influence the duration of treatment with chest tubes, one of
these being the clinical decision per se to remove the chest tube,
which has been shown to have interobserver variability [2].
Electronic drainage systems have shown increased agreement
rate concerning clinical decision making regarding chest tube
removal [2]. Besides adding objectivity to the clinical decision of
chest tube removal, electronic drainage systems have shown superiority to traditional drainage systems in a limited number of studies.
At present, there are five prospective randomized trials comparing
†
Presented at the 28th Annual Meeting of the European Association for CardioThoracic Surgery, Milan, Italy, 11–15 October 2014.
electronic with traditional chest tube drainage [3–7]. In addition,
there are observational studies [8, 9]. Most studies included various
types of lung resections, and used algorithms with external suction
in both groups of varied length and strength [2, 3, 6–11].
In our institution, we routinely use traditional water seal chest
drainage without external suction to facilitate early mobilization
postoperatively. Until the advancement of an electronic drainage
system that allowed mobilization with the device, it was not possible to apply suction without immobilizing patients to the extent of
the suction tube. So far, studies evaluating suction versus water seal
have not collectively given clear-cut recommendations on how to
manage chest tubes following lung resections [12–15]. With the
advent of the electronic drainage system, we wanted to test this
system versus our routine drainage system, where both study
groups had equal opportunity to mobilize early postoperatively. In
addition, because of ever increasing demands to reduce costs, hospital stay and document quality in patient care, we decided to
conduct a randomized controlled trial as part of a medico-technical
© The Author 2015. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.
THORACIC
CONCLUSIONS: Electronic drainage systems did not reduce chest tube duration or length of hospitalization significantly compared with
traditional water seal drainage when a strict algorithm for chest tube removal was used. This algorithm allowed delegation of chest tube
removal to staff nurses, and in some patients chest tubes could be removed safely on the day of surgery.
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M. Lijkendijk et al. / European Journal of Cardio-Thoracic Surgery
evaluation before adopting electronic drainage systems as a routine
following thoracic surgery.
METHODS
The present study was approved by the Regional Ethics Committee
and the Danish Data Protection Agency. The study was powered to
detect a difference in length of hospitalization of a least 1 day
because a shorter hospital stay would reduce costs. Eligible for
inclusion were all patients admitted for lobectomy by thoracotomy
or video-assisted thoracic surgery (VATS), age older than 18 years
and who were able to read and understand the information regarding the study.
Exclusion criteria were as follows: previous history of pulmonary
or cardiac surgery, expected difficulties with postoperative mobilization, patients not able to co-operate with a lung physiotherapist, participation in concomitant studies or trial in the department,
where a different drainage protocol could influence results,
postoperative mechanical ventilation, the insertion of more than
one chest tube perioperative and finally bilobectomy or middle
lobectomy.
Patients were enrolled into the study by the thoracic surgeons 1
day prior to surgery, when being examined and evaluated for
surgery. Written informed consent was obtained from all patients.
Data collection included the following: age, gender, BMI, forced
expiratory volume in 1 second (FEV1), type of surgery, state of the
inter-lobar fissure, pleural adhesions, postoperative pain score
(VAS) with regard to chest tube removal and air leakage three
times every day until chest tube removal. Study endpoints were as
follows: time of optimal chest tube removal —meaning when it
was possible according to the criteria of removal, time of actual
chest tube removal—meaning when it was actually removed and
length of stay (LOS) in hospital, which was the primary outcome.
Complications such as need for chest tube reinsertion, need of
pleurocentesis within 30 days, development of pleural empyema
within 30 days and any need of antibiotic treatment for postoperative pneumonia were also registered.
A standard chest tube (Ch. 24) was placed routinely at the end of
the lobectomy procedures. Following surgery, while still on the operating table, patients were randomized to receive intervention with
either an electronic drainage system, Thopaz® (Medela AG, Baar,
Switzerland) or a traditional drainage system, Thora-Seal® (Covidien,
Mansfield, MA, USA) (Fig. 1). Randomization was done by use of
sequentially numbered, opaque, sealed envelopes managed by the
research unit of the department. Once the surgeon determined that
there were no intraoperative exclusion criteria present (i.e. need of
two chest tubes or bilobectomy), the sealed envelope was opened
by the research unit, and read to the surgeon at the end of surgery.
Intervention by electronic drainage also included continuous
suction effect of −15 cm H2O whereas traditional drainage by a
single chamber 370 ml water seal used simple gravity without a
possibility of applying external suction. The large water seal is
used routinely in the department to prevent reverse air flow [16].
All the patients subsequently followed our routine postoperative
observation regimen and pain management, and they were mobilized on the same day of surgery. Chest tubes were removed using
the following strict algorithm: In the electronic group, the chest
tube was considered eligible for removal when air leakage had
ceased to ≤20 ml/min for 6 consecutive hours or ≤50 ml/min for 12
consecutive hours without any visible spikes on the digital display
[17], and always in a fully mobilized patient with no or just minor
pain (VAS-level 2–3 on a 10-point scale).
In the traditional group, the chest tube was considered eligible
for removal when no air bubble was visible in the water seal
during coughing on a fully mobilized patient with no or just minor
pain (VAS-level 2–3 on a 10-point scale).
In both groups, the earliest time allowed for removal was 6 h
postoperatively, and for this it was also required that fluid production was serous with a total volume of <200 ml on the day of
surgery or <400 ml on the following day, as this is our routine
management.
Figure 1: The two drainage systems used. The Thopaz system by Medela to the left and the Thora-Seal system by Covidien to the right.
M. Lijkendijk et al. / European Journal of Cardio-Thoracic Surgery
variables were also used to compare the two groups. IBM’s SPSS
21.0 was used to perform statistical analysis. Nomenclature used
in this paper is in accordance with the consensus definitions [1].
RESULTS
A total of 338 lobectomies were performed between January 2012
and August 2013. Of these, 86 patients participated in other research studies, and were consequently excluded. Another 147
were either not assessed for inclusion because of oversight or did
not meet the inclusion criteria. No patient that was asked to participate refused, and this left 105 patients for randomization. A
flow diagram of the study is illustrated in Fig. 2. Baseline variables
were similar between the two groups with no significant differences as given in Table 1.
We found no significant difference between the electronic group
and traditional group in optimal chest tube duration on intentionto-treat basis (HR = 0.83; 95% CI: 0.55–1.25; P = 0.367) (Fig. 3), actual
chest tube duration (HR = 0.84; 95% CI: 0.55–1.26; P = 0.397) (Fig. 4)
or length of hospital stay (HR = 0.91; 95% CI: 0.59–1.39; P = 0.651)
THORACIC
The study was open labelled as blinding was impossible with
two different drainage systems (Fig. 1). Once the chest tubes were
removed, surgeons and staff nurses were typically unaware of
which chest tube drainage system had been used. This information was not blinded, but our staff would have to actively seek this
information going back in the electronic medical charts.
Chest tubes were observed at least once in every work shift by
the staff nurses (three shifts of 8 h each per 24 h), and the decision
of chest tube removal was delegated to the clinical staff nurse
in charge of the patient. Chest X-rays were routinely obtained
2 hours after removal of the chest tube and again 10–14 days
following surgery in our outpatient clinic.
Statistical analysis consisted of Cox proportional hazard regression analysis adjusting for FEV1 (categorized as <70, 70–90, >90%),
gender, age (categorized as <60, 60–70, >70 years), BMI (categorized as <25, 25–30, >30), surgical approach (VATS or open surgery)
and presence of pleural adhesions and/or incomplete inter-lobar
fissures. Time was distinguished as possible (optimal) and actual
time for chest tube removal, as well as length of hospitalization.
Statistical significance was determined as P < 0.05. A χ 2 test,
Shapiro–Wilks test for normality and Student’s t-test for baseline
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Figure 2: Flow diagram of the trial according to CONSORT [18].
M. Lijkendijk et al. / European Journal of Cardio-Thoracic Surgery
896
Table 1: Comparison of preoperative and operative
factors in the study groups
Variables
Electronic
(n = 55)
Traditional
(n = 50)
P-value
Agea
Gender (male/female)
FEV1%
BMI
Surgery (n = VATS/thoracotomy)
Incomplete fissure or
adhesions (%)
Lobes removed
LUL
LLL
RUL
RLL
69.5 (48–87)
21/34
82.8 (16.4)
26.0 (4.1)
25/30
58
67 (46–85)
18/32
84.4 (16.9)
24.8 (5.1)
16/34
54
0.099
0.815
0.629
0.228
0.158
0.850
20
11
11
13
19
8
12
11
0.925
LUL: left upper lobe; LLL: left lower lobe; RUL: right upper lobe; RLL:
right lower lobe.
a
Age shown as median and range. Other continuous variables
expressed as mean with standard deviation in parenthesis. P-values
from Student’s t-test on continuous variables or χ 2 on categorical
variables.
Figure 4: Cox regression curve showing actual chest tube duration (the time
when the chest tube was actually removed).
Figure 5: Cox regression curve showing length of hospital stay (days from operation to discharge).
Figure 3: Cox regression curve showing optimal chest tube duration (the time
when the algorithm for chest tube removal was fulfilled).
(Fig. 5). The presence of pleural adhesions or an incomplete fissure
was a significant predictor of chest tube duration (HR = 1.72; 95%
CI: 1.12–2.65; P = 0.014), but surgical approach was not (HR = 0.95;
95% CI: 0.61–1.48; P = 0.826).
The protocol was violated in four instances in the electronic
group by switching drainage system. Another patient was an
outlier with a 35-day hospitalization resulting from a complicated
postoperative course following resection of a large completely
necrotic tumour occupying the entire lobe, which was removed in
a contaminated chest cavity. We decided to perform the analysis
per-protocol without the 5 patients mentioned, and found no
significant difference between the electronic group and traditional
group in optimal chest tube duration (HR = 0.80; 95% CI: 0.52–
1.22; P = 0.297), actual chest tube duration (HR = 0.80; 95% CI:
0.52–1.22; P = 0.301) or length of hospital stay (HR = 0.71; 95% CI:
0.46–1.11; P = 0.137). FEV1 (HR = 0.41; 95% CI: 0.20–0.84, P =
0.049) and the presence of pleural adhesions or an incomplete
fissure (HR = 1.60; 95% CI: 1.03–2.46, P = 0.036) were both significant predictors of chest tube duration. Medians and IQR’s for the
groups are given in Table 2.
Removal of six chest tubes was postponed on the basis of fluid
production >400 ml.
Six chest tubes (five in the electronic group and one in the traditional group) were removed safely on the same day of surgery, with
no need for reinsertion of chest tubes. According to our algorithm,
15 chest tubes could have been removed on Day 0. However, most
chest tubes were removed in close proximity to the morning rounds
as shown graphically in Fig. 6. All chest tubes were removed prior to
discharge, and all patients discharged to their homes.
DISCUSSION
This study found no significant difference on the overall chest
tube duration and LOS between the electronic drainage system
and the traditional water seal drainage, and therefore our results
Table 2: Descriptive numeral comparison of endpoints
between the two groups
Endpoints
Intention-to-treat
Optimal chest tube durationa
Chest tube duration
Length of stay
Per-protocol
Optimal chest tube durationa
Chest tube duration
Length of stay
Electronic (n = 55)
27 (18–57)
41 (22–68)
4 (3–6)
Electronic (n = 50)
25 (16–56)
42 (22–68)
4 (3–5)
Traditional (n = 50)
43.5 (21–66)
46.5 (24–70)
5 (3–6)
Traditional (n = 50)
43.5 (21–66)
46.5 (24–70)
5 (3–6)
Results are shown descriptively as median in hours (chest tube
duration) with IQR in parenthesis and median in days (length of stay).
a
The time when the algorithm for chest tube removal was fulfilled.
Figure 6: Illustration of chest tube removal in close proximity to morning
rounds Day 1—19–24 h after surgery, Day 2—43–48 h after surgery and Day 3—
67–72 h after surgery.
differ from the majority of published literature comparing electronic drainage with traditional water seal drainage.
Previous studies showed significant reduction in both chest
tube duration and LOS in favour of electronic drainage systems
[5, 7, 19], and other studies have shown significant reduction in
chest tube duration and tendencies in shorter hospital stay favouring electronic drainage systems [6, 10]. Studies comparing electronic drainage with traditional drainage showed chest tube
durations of 2.5 days in the electronic group vs 4.4 in the traditional
group [19], 4 vs 4.9 days [5] and 3.1 vs 3.9 days [6]. In our study, the
mean chest tube duration was 1.9 days in the electronic group vs
2.2 in the traditional group. One reason for the shorter chest tube
duration in the traditional group could be our strict algorithm for
removal, as they were observed and evaluated for removal three
times every day just as the electronic group. Otherwise, one could
expect that the traditional chest tubes would be left in the patients
for a longer period of time even though it would be possible from a
clinical point of view to remove them. If previous studies did not
have the same considerations/algorithm for chest tube removal in
the traditional group, this could contribute to explain why they
found a difference between drainage systems. In our study, the
mean LOS was approximately 5 days in both groups, which is compatible with findings in other studies [5, 7].
The finding that incomplete fissures, adhesions and lung function (FEV1) were all significant predictors of chest tube duration
confirms what has already been reported previously [20, 21].
897
When we decided to introduce and test the electronic drainage
system in our department, it was important for us to use a simple algorithm and instructions for chest tube removal, first of all to minimize variation in clinical judgement of chest tube removal, but also
because it would be easy to delegate this decision to our staff nurses
without having to consult the surgeon on duty. Our study confirms
that the decision to remove chest tubes can be successfully delegated to the staff nurse in care of newly operated lung cancer
patients.
Even though the electronic drainage system device was used routinely in our ward before initiation of this trial, our data might still
have been influenced by a learning curve, as we noticed that even
experienced surgeons switched the drainage system within the
electronic group in 4 cases because of uncertainty in the interpretation of the system and the data displayed. These misunderstandings, however, did not influence our results, as the conclusion
remained the same when data were analysed according to the intention-to-treat and per-protocol principles. In addition, one previous study showed an effect of the electronic device despite a
learning curve [19]. We also discovered that many of the chest tubes
were removed in close proximity to morning rounds (Fig. 6), which
could reflect that staff nurses were not comfortable making the decision to remove a chest tube despite our algorithm or that it was
simply daytime when most staff were present.
One of our contraindications for chest tube removal was fluid production of more than 400 ml, which postponed chest tube removal
in 6 patients. The clinical significance of higher serous fluid production was recently studied by Bjerregaard et al. [22] who demonstrated
that even with a serous fluid production of 500 ml, chest tubes could
be removed safely following VATS lobectomies, but this information
was not available to us at the time we designed the protocol.
The present study has limitations. Most apparent is the fact that
the intervention was not blinded to the patients and staff in the
ward. Also, the intervention in the electronic drainage system group
did in fact consist of two simultaneous interventions compared with
the control group with a traditional drainage system, namely that it
was electronic and at the same time applied suction. As emphasized
in the introduction, our routine is to facilitate early mobilization in
all patients, and this would not have been possible if we applied external suction to our traditional drainage system. On the basis of this,
there could be statistical interactions that we cannot account for. It
may also be argued that because of the limited sample size, we may
have overlooked a difference between the two drainage systems,
which was less than 1 day, but the study was powered to detect a
difference in length of hospitalization of a least 1 day because this
was considered to be a clinically relevant difference for the patient
as a shorter hospital stay would reduce costs.
In striving to minimize hospital stay and reduce costs, our experience with a strict algorithm for chest tube removal could be a valuable way forward for others regardless of choice of drainage system.
However, the fact that there was no difference in LOS between the
electronic drainage system used and traditional drainage by water
seal suggests that factors besides chest tube duration need attention
as well to facilitate fast-track thoracic surgery.
In conclusion, this study found no significant difference in chest
tube duration or length of hospitalization, but the electronic
device facilitated delegation of chest tube removal to the staff
nurses, because it could be evaluated objectively, and because
clear algorithms for removal were defined.
Conflict of interest: none declared.
THORACIC
M. Lijkendijk et al. / European Journal of Cardio-Thoracic Surgery
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M. Lijkendijk et al. / European Journal of Cardio-Thoracic Surgery
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APPENDIX. CONFERENCE DISCUSSION
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Dr M. Ibrahim (Rome, Italy): Even though this study arrives after the publication
of a meaningful multicentre international clinical trial evaluating the outcomes
of electronic and traditional chest drainage systems, it seems to bring new
insight into the topic. I have a few questions for you in order to clarify some
aspects.
First of all, you removed the chest tube when no bubbles were visible in the
analogical drainage and when the air leaks were less than 20 ml/min for 6 consecutive hours or less than 50 ml/min for 12 h in the digital group. There is a
clear discrepancy between the two groups in terms of the air leak management. This could represent an important bias. What is your opinion on this?
Dr Lijkendijk: I agree that it could represent a bias. Maybe if we had looked at
the analogue chest drainage system and allowed tiny bubbles before removing
chest tubes, it could have been fairer to the Thora-Seal chest drainage group.
We know that there is a lot of inter-observer variability when removing chest
tubes postoperatively, and so we needed to have clear criteria as to how we
have to remove the chest tubes. Actually, the Thora-Seal group was managed,
and the analogue chest tube drainage system was managed as we used to do in
our department. We used to remove the chest tubes when there is no air
leakage. So there was nothing different in how we managed these patients and
this drainage type system.
As for the criteria that we used in the digital group, we looked to the literature and found a study by Dr Cerfolio, who used the 20 ml/min criterion when
removing the digital chest tube device. The 50 ml/min is a criterion that was
used in another thoracic centre in Denmark for quite some time successfully.
So these are the reasons why we chose to have this algorithm.
Dr Ibrahim: Secondly, you claim to have planned chest tube removal if the
fluid production was less than 400 cc, but you don’t clarify if you have considered the characteristics of the fluid.
Moreover, the average time of chest tube duration was very short, as you
have shown. For that reason, it could be interesting to know the duration in the
subset of patients who had undergone VATS lobectomy and how it might have
influenced the results. Do you have the hard data about this? Alternatively, are
you planning on obtaining them and using them for further studies?
Dr Lijkendijk: As regards the fluid, how the fluid was?
Dr Ibrahim: Yes.
Dr Lijkendijk: We did observe the patients for signs of ongoing bleeding.
Obviously, we didn’t remove the chest tubes if this was the case.
And as for the data on the VATS subgroup, I do have some data with me concerning the length of hospital stay, but unfortunately, we didn’t extract the data
on chest tube duration yet. It is something that we will use further. The data on
the length of hospital stay in the VATS subgroup is in actual numbers very
similar to the thoracotomy subgroup.
Dr Ibrahim: Okay. And the last question, I seem to have understood that the
digital group received 15 mmHg suction. Otherwise, the analogue group did
not receive suction; is that correct? And I think this aspect could have influenced the results. What do you think?
Dr Lijkendijk: Well, we are not convinced that applying suction would
benefit or facilitate an early chest tube removal. We used suction in the digital
device because it’s recommended by the company, and if we don’t use suction,
it works with a one-way valve only, the Thopaz system.
We believe that essentially, it’s a study comparing two different drainage
systems and way of handling the postoperative chest tube management, and
we choose to focus on the mobilization of the patient and wanted to not put
suction on our traditional device as it would make the patient stay near a
suction line. So this is why we did this.
Dr T. Treasure (London, UK): In electronics, there is a clear distinction
between digital and analogue signals but in your very nice study, you are replacing visual inspection with an electronic device.
Dr Lijkendijk: Yes.
Dr Treasure: It is the detection device which is digital. There is an implied dichotomy, that if it isn’t digital must be analogue, which doesn’t apply to chest
tubes. Do you want to defend the use of the word ‘analogue chest tube’?
Otherwise, I would suggest we don’t perpetuate it because what you are talking
about is visually inspected conventional chest drain.
Dr Lijkendijk: Yes. Well, we could have used conventional chest drainage.
Dr Treasure: As Dr Ibrahim did.
Dr Lijkendijk: Yes, yes, exactly. Well, I don’t have a long explanation of why
we used that word instead of conventional.